FIBROUS STRUCTURES WITH IMPROVED SURFACE PROPERTIES AND COLD WATER SOLUBILITY

Abstract

Fibrous structures having improved surface smoothness, good wet feel, and are cold water soluble.

Claims

1. A fibrous structure comprising a first web material and a surface comprising a surface material different from the first web material, wherein the surface material comprises a blended PVOH fiber composition comprising: a blend of a first PVOH having a level of hydrolysis between about 70% to about 90% and a second PVOH having a level of hydrolysis between about 92% to about 99%; wherein the amount of the first PVOH is between about 35% to 75% and the amount of the second PVOH is between about 25% to about 65%, based on the weight of the blended PVOH fiber composition; wherein the blended PVOH fiber composition has a crystallinity of less than 40% and a level of hydrolysis of at least 90%; and wherein the blended PVOH fiber composition is cold water soluble.

2. The fibrous structure according to claim 1 having a TS7 value of less than 7.9.

3. The fibrous structure according to claim 1 having a Finished Product Wet Tack Area of less than 9,500 mg/cm.

4. The fibrous structure according to claim 1 having a Finished Product Wet Tack Area of less than 8,600 mg/cm.

5. The fibrous structure according to claim 1 wherein the first web material comprises a plurality of fibrous elements.

6. The fibrous structure according to claim 5 wherein at least one of the fibrous elements comprises a fiber.

7. The fibrous structure according to claim 6 wherein the fiber comprises a pulp fiber.

8. The fibrous structure according to claim 6 wherein the fiber comprises a non-naturally occurring fiber.

9. The fibrous structure according to claim 5 wherein at least one of the fibrous elements comprises a filament.

10. The fibrous structure according to claim 1 wherein the first web material comprises a wet laid fibrous structure ply.

11. The fibrous structure according to claim 1 wherein the surface of the fibrous structure further comprises at least a portion of the first web material.

12. The fibrous structure according to claim 1 wherein the surface material is associated with the first web material.

13. The fibrous structure according to claim 12 wherein the surface material is associated with the first web material through one or more bond sites.

14. The fibrous structure according to claim 1 wherein the surface material comprises a second web material.

15. The fibrous structure according to claim 14 wherein the second web material comprises a plurality of fibrous elements.

16. The fibrous structure according to claim 15 wherein at least one of the fibrous elements comprises a fiber.

17. The fibrous structure according to claim 16 wherein the fiber comprises a non-naturally occurring fiber.

18. The fibrous structure according to claim 17 wherein the non-naturally occurring fiber comprises a polysaccharide.

19. The fibrous structure according to claim 18 wherein the polysaccharide is selected from the group consisting of: cellulose, cellulose derivatives, starch, starch derivatives, hemicelluloses, hemicelluloses derivatives, and mixtures thereof.

20. The fibrous structure according to claim 15 wherein at least one of the fibrous elements comprises a filament.

21. The fibrous structure according to claim 20 wherein the filament comprises polyvinyl alcohol.

22. The fibrous structure according to claim 20 wherein the filament comprises a polysaccharide.

23. A blended PVOH fiber composition comprising: a blend of a first PVOH having a level of hydrolysis between about 70% to about 90% and a second PVOH having a level of hydrolysis between about 92% to about 99%; wherein the amount of the first PVOH is between about 35% to 75% and the amount of the second PVOH is between about 25% to about 65%, based on the weight of the blended PVOH fiber composition; wherein the blended PVOH fiber composition has a crystallinity of less than 40% and a level of hydrolysis of at least 90%; and wherein the blended PVOH fiber composition is cold water soluble.

24. The blended PVOH composition according to claim 23, wherein the hydrolysis level of the first PVOH is between about 80% to about 90% and the amount of the first PVOH is from about 45% to about 65%.

25. The blended PVOH composition according to claim 23, wherein the hydrolysis level of the second PVOH is between about 92% to about 97% and the amount of the second PVOH is from about 35% to about 60%.

26. A method of producing a blended PVOH fiber composition comprising: providing a first PVOH having a level of hydrolysis between about 70% to about 90%; providing a second PVOH having a level of hydrolysis between about 92% to about 99%; blending the first and second PVOH to produce a PVOH fiber composition; wherein the amount of the first PVOH is between about 35% to 75% and the amount of the second PVOH is between about 25% to about 65%, based on the weight of the blended PVOH fiber composition.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic representation of an example of a fibrous structure according to the present invention.

[0009] FIG. 2 is a cross-sectional view of FIG. 1 taken along line 2-2.

[0010] FIG. 3 is a schematic cross-sectional representation of an example of a multi-ply fibrous structure according to the present invention.

[0011] FIG. 4 is a schematic cross-sectional representation of another example of a fibrous structure according to the present invention.

[0012] FIG. 5 is a schematic representation of a process for making a fibrous structure according to the present invention.

[0013] FIG. 6 is a schematic partial top view representation of a surface material source used in the process shown in FIG. 5.

[0014] FIG. 7 is a schematic representation of another fibrous structure according to the present invention.

[0015] FIG. 8A is a schematic representation of an example of a patterned molding member according to the present invention.

[0016] FIG. 8B is a further schematic representation of a portion of the molding member of FIG. 8A.

[0017] FIG. 8C is a cross-sectional view of FIG. 8B taken along line 8C-8C.

[0018] FIG. 9A is a schematic representation of an example of a first web material according to the present invention made using the molding member of FIG. 8A.

[0019] FIG. 9B is a cross-sectional view of FIG. 9A taken along line 9B-9B.

[0020] FIG. 10 is a schematic representation of an example of a through-air-drying papermaking process for making a first web material according to the present invention.

[0021] FIG. 11A is a schematic representation of a Glide on Skin Test Method set-up.

[0022] FIG. 11B is a schematic top view representation of FIG. 11A.

[0023] FIG. 11C is a schematic representation of a Probe used in FIG. 11A.

[0024] FIG. 11D are different views of the sled used in FIG. 11A.

[0025] FIG. 12 is a graph comparing the percent crystallinity in view of the hydrolysis levels of pure PVOH vs. blended PVOH.

[0026] FIG. 13 is a graph summarizing PVOH blend composition properties.

DETAILED DESCRIPTION OF THE INVENTION

[0027] The Present Invention includes a polyvinyl alcohol (PVOH) nonwoven fibrous structure surface material formed from PVOH fibrous elements that does not rapidly dissolve during consumer use but is cold water soluble, such that it is compatible with a down the drain application. In embodiments PVOH fibrous elements comprise a mix of two PVOH components having different degrees of hydrolysis, for example a blend comprising a high hydrolyzed PVOH (>90%) with a medium hydrolyzed PVOH (75 to 90%), Particularly, an 88% hydrolyzed PVOH is mixed with a 98% hydrolyzed PVOH at an inclusion level between 26 and 90 wt % of the 88% hydrolyzed grade. By mixing a lower crystalline content PVOH with a higher crystalline content PVOH, surprisingly the resulting spun fibrous element does not have a % crystallinity in-between the two pure materials but is actually much lower, very close to or even lower than the pure lower crystalline content PVOH.

[0028] Furthermore, a web composed of the blended fiber composition is substantially cold water soluble just like a web spun from a pure medium hydrolyzed PVOH. This surprising behavior is due to the individual components being very miscible. Portions of polymer chains with acetate groups are well dispersed and mixed with portions of chains with hydroxyl groups which prevents the hydroxyl groups from hydrogen bonding. If the degree of hydrolysis between the two components is too different, the polymers won't mix sufficiently, the hydroxyl groups will form hydrogen bonds, and the crystallinity of the blend will not be suppressed. For example, blending two PVOH grades of 74% and 98% hydrolysis results in phase separation and higher percent crystallinity in the fibrous element. The lower crystalline fibrous element made from two miscible PVOHs of different degrees of hydrolysis are both cold water soluble due to the low crystallinity and have a relatively low wet tack due to the presence of the highly hydrolyzed PVOH. Providing a nonwoven layer of the blended PVOH melt blown fibrous elements onto a wet laid cellulosic structure creates a tissue with the desired combination of a plush surface (Emtec), slow dissolution, and compatibility with wastewater treatment facilities.

[0029] Without being limited to theory it is also believed other factors such as miscibility, phase separation, and polymer branching are important in determining the fibrous element properties of the Present Invention. For example, miscibility is a property allowing the spinning of small diameter fibrous elements having a diameter less than 5 microns. Phase separated domains, regions of high crystallinity, and/or inhomogeneities can serve as defects in the melt resulting in fiber breakage in the spin line prior to full attenuation. Branching in polymers is known to disrupt crystallinity. A fibrous layer spun from a branched highly hydrolysis PVOH may exhibit the desired combination of low crystallinity, cold-water solubility, and low wet tack.

[0030] Addition of water-soluble plasticizers such as glycerol, sorbitol, mannitol, etc. are known to disrupt PVOH crystallinity if included at high enough levels. PVOH formulations used in single unit dose films often use a plasticizer to decrease crystallinity and increase cold water dissolution rate of the pads. A concern in using plasticizers in the Present Invention is that PVOH fibers with a high degree of plasticizer may become sticky during use or under high humidity conditions-high wet tack. In embodiments low levels of plasticizer may be added to the PVOH blends without negatively impacting high wet tack under humid conditions.

Definitions

[0031] Fibrous element as used herein means an elongate particulate having a length greatly exceeding its average diameter, i.e. a length to average diameter ratio of at least about 10. A fibrous element may be a filament or a fiber. In embodiments, the fibrous element is a single fibrous element rather than a yarn comprising a plurality of fibrous elements.

[0032] The fibrous elements of the present invention may be spun from polymer melt compositions via suitable spinning operations, such as meltblowing and/or spunbonding and/or they may be obtained from natural sources such as vegetative sources, for example trees.

[0033] The fibrous elements of the present invention may be monocomponent and/or multicomponent. For example, the fibrous elements may comprise bicomponent fibers and/or filaments. The bicomponent fibers and/or filaments may be in any form, such as side-by-side, core and sheath, islands-in-the-sea and the like.

[0034] Filament as used herein means an elongate particulate as described above that exhibits a length of greater than or equal to 5.08 cm (2 in.) and/or greater than or equal to 7.62 cm (3 in.) and/or greater than or equal to 10.16 cm (4 in.) and/or greater than or equal to 15.24 cm (6 in.).

[0035] Filaments are typically considered continuous or substantially continuous in nature. Filaments are relatively longer than fibers. Non-limiting examples of filaments include meltblown and/or spunbond filaments. Non-limiting examples of polymers that can be spun into filaments include natural polymers, such as starch, starch derivatives, cellulose, such as rayon and/or lyocell, and cellulose derivatives, hemicellulose, hemicellulose derivatives, and synthetic polymers including, but not limited to polyvinyl alcohol filaments and/or polyvinyl alcohol derivative filaments, and thermoplastic polymer filaments, such as polyesters, nylons, polyolefins such as polypropylene filaments, polyethylene filaments, and biodegradable or compostable thermoplastic fibers such as polylactic acid filaments, polyhydroxyalkanoate filaments, polyesteramide filaments, and polycaprolactone filaments. The filaments may be monocomponent or multicomponent, such as bicomponent filaments.

[0036] Fiber as used herein means an elongate particulate as described above that exhibits a length of less than 5.08 cm (2 in.) and/or less than 3.81 cm (1.5 in.) and/or less than 2.54 cm (1 in.). Fibers are typically considered discontinuous in nature. Non-limiting examples of fibers include pulp fibers, such as wood pulp fibers, and synthetic staple fibers such as polypropylene, polyethylene, polyester, copolymers thereof, rayon, lyocell, glass fibers and polyvinyl alcohol fibers.

[0037] Staple fibers may be produced by spinning a filament tow and then cutting the tow into segments of less than 5.08 cm (2 in.) and/or less than 3.81 cm (1.5 in.) and/or less than 2.54 cm (1 in.) thus producing fibers; namely, staple fibers.

[0038] In embodiments of the present invention, a fiber may be a naturally occurring fiber, which means it is obtained from a naturally occurring source, such as a vegetative source, for example a tree and/or plant, such as trichomes. Such fibers are typically used in papermaking and are oftentimes referred to as papermaking fibers. Papermaking fibers useful in the present invention include cellulosic fibers commonly known as wood pulp fibers. Applicable wood pulps include chemical pulps, such as Kraft, sulfite, and sulfate pulps, as well as mechanical pulps including, for example, groundwood, thermomechanical pulp and chemically modified thermomechanical pulp. Chemical pulps, however, may be preferred since they impart a superior tactile sense of softness to fibrous structures made therefrom. Pulps derived from both deciduous trees (hereinafter, also referred to as hardwood) and coniferous trees (hereinafter, also referred to as softwood) may be utilized. The hardwood and softwood fibers can be blended, or alternatively, can be deposited in layers to provide a stratified web. Also applicable to the present invention are fibers derived from recycled paper, which may contain any or all of the above categories of fibers as well as other non-fibrous polymers such as fillers, softening agents, wet and dry strength agents, and adhesives used to facilitate the original papermaking.

[0039] In embodiments, the wood pulp fibers are selected from the group consisting of hardwood pulp fibers, softwood pulp fibers, and mixtures thereof. The hardwood pulp fibers may be selected from the group consisting of: tropical hardwood pulp fibers, northern hardwood pulp fibers, and mixtures thereof. The tropical hardwood pulp fibers may be selected from the group consisting of: eucalyptus fibers, acacia fibers, and mixtures thereof. The northern hardwood pulp fibers may be selected from the group consisting of: cedar fibers, maple fibers, and mixtures thereof. In addition to the various wood pulp fibers, other cellulosic fibers such as cotton linters, rayon, lyocell, trichomes, seed hairs, and bagasse fibers can be used in this invention. Other sources of cellulose in the form of fibers or capable of being spun into fibers include grasses and grain sources.

[0040] Trichome or trichome fiber as used herein means an epidermal attachment of a varying shape, structure and/or function of a non-seed portion of a plant. In embodiments, a trichome is an outgrowth of the epidermis of a non-seed portion of a plant. The outgrowth may extend from an epidermal cell. In one embodiment, the outgrowth is a trichome fiber. The outgrowth may be a hairlike or bristlelike outgrowth from the epidermis of a plant.

[0041] Trichome fibers are different from seed hair fibers in that they are not attached to seed portions of a plant. For example, trichome fibers, unlike seed hair fibers, are not attached to a seed or a seed pod epidermis. Cotton, kapok, milkweed, and coconut coir are non-limiting examples of seed hair fibers.

[0042] Further, trichome fibers are different from nonwood bast and/or core fibers in that they are not attached to the bast, also known as phloem, or the core, also known as xylem portions of a nonwood dicotyledonous plant stem. Non-limiting examples of plants which have been used to yield nonwood bast fibers and/or nonwood core fibers include kenaf, jute, flax, ramie and hemp.

[0043] Further trichome fibers are different from monocotyledonous plant derived fibers such as those derived from cereal straws (wheat, rye, barley, oat, etc), stalks (corn, cotton, sorghum, Hesperaloe funifera, etc.), canes (bamboo, bagasse, etc.), grasses (esparto, lemon, sabai, switchgrass, etc), since such monocotyledonous plant derived fibers are not attached to an epidermis of a plant.

[0044] Further, trichome fibers are different from leaf fibers in that they do not originate from within the leaf structure. Sisal and abaca are sometimes liberated as leaf fibers.

[0045] Finally, trichome fibers are different from wood pulp fibers since wood pulp fibers are not outgrowths from the epidermis of a plant; namely, a tree. Wood pulp fibers rather originate from the secondary xylem portion of the tree stem.

[0046] As used herein the term non-wood fiber(s) or non-wood content means naturally-occurring fibers derived from non-wood plants, including animal fibers, mineral fibers, plant fibers and mixtures thereof, and specifically excluding non-naturally-occurring fibers (e.g., synthetic fibers). Animal fibers may, for example, be selected from the group consisting of: wool, silk and other naturally-occurring protein fibers and mixtures thereof. The plant fibers may, for example, be obtained directly from a plant. Nonlimiting examples of suitable plants include cotton, cotton linters, flax, sisal, abaca, hemp, hesperaloe, jute, bamboo, bagasse, kudzu, corn, sorghum, gourd, agave, loofah, trichomes, seed-hairs, wheat, and mixtures thereof.

[0047] Non-wood fibers of the present disclosure may be derived from one or more non-wood plants of the family Asparagaceae. Suitable non-wood plants may include, but are limited to, one or more plants of the genus Agave such as A. tequilana, A. sisalana and A. fourcroyde, and one or more plants of the genus Hesperaloe such as H. funifera, H. parviflora, H. nocturna, H. Changi, H. tenuifolia, H. engelmannii, and H. malacophylla. Further, the non-wood fibers of the present disclosure may be prepared from one or more plants of the of the genus Hesperaloe such as H. funifera, H. parviflora, H. nocturna, H. chiangii, H. tenuifolia, H. engelmannii, and H. malacophylla.

[0048] As used herein the term wood fiber(s) or wood content means fibers derived from both deciduous trees (hereinafter, also referred to as hardwood) and coniferous trees (hereinafter, also referred to as softwood) may be utilized. Wood fibers may be short (typical of hardwood fibers) or long (typical of softwood fibers). Nonlimiting examples of short fibers include fibers derived from a fiber source selected from the group consisting of Acacia, Eucalyptus, Maple, Oak, Aspen, Birch, Cottonwood, Alder, Ash, Cherry, Elm, Hickory, Poplar, Gum, Walnut, Locust, Sycamore, Becch, Catalpa, Sassafras, Gmelina, Albizia, Anthocephalus, and Magnolia. Nonlimiting examples of long fibers include fibers derived from Pine, Spruce, Fir, Tamarack, Hemlock, Cypress, and Cedar.

[0049] As used herein the term synthetic fiber(s) or synthetic content means fibers human-made fibers, and specifically excludes wood fibers and non-wood fibers. Synthetic fibers can be used, in combination with non-wood fibers (e.g., bamboo) in the fibrous structures of the present disclosure. Synthetic fibers may be polymeric fibers. Synthetic fibers may comprise elastomeric polymers, polypropylene, polyethylene, polyester, polyolefin, polyvinyl alcohol and nylon, which are obtained from petroleum sources. Additionally, synthetic fibers may be polymeric fibers comprising natural polymers, which are obtained from natural sources, such as starch sources, protein sources and/or cellulose sources may be used in the fibrous structures of the present disclosure. The synthetic fibers may be produced by any suitable methods known in the art.

[0050] Fibrous structure(s), web(s) that form the fibrous structure(s), layer(s) of a fibrous structure(s) (including at least one of or each of a first and a second layer of a ply), and/or sheet(s) of a fibrous structure may comprise at least about 5%, about 10%, about 15%, about 20%, about 30%, about 35% about 40%, about 50%, about 75%, about 80%, or about 100% non-wood content, or from about 5% to about 15%, from about 10% to about 30%, from about 20% to about 40%, from about 30% to about 50%, from about 40% to about 60%, from about 50% to about 70%, from about 55% to about 95%, from about 65% to about 85%, from about 60% to about 80%, from about 70% to about 90%, from about 80% to about 100%, from about 90% to about 100%, from about 95% to about 100%, or from about 97.5% to about 100% non-wood content (e.g., bamboo, abaca, hemp, etc.), specifically reciting all 0.1% increments within the above-recited ranges of this paragraph and all ranges formed therein or thereby.

[0051] As used herein, the term biodegradable or biodegradable polymer generally refers to a material that degrades from the action of naturally occurring microorganisms, such as bacteria, fungi, and algae; environmental heat; moisture; or other environmental factors. The biodegradability of a material may be determined using ASTM Test Method 5338.92. OECD 301B is the biodegradation test used for determining compatibility of a material with wastewater treatment facilities.

[0052] As used herein cold water soluble refers to a material that does not exhibit any residual microstructure after being placed in a concentrated solution of cold water as described in the Cold Water Solubility Test Method, as described herein.

[0053] As used herein Wet Tack is measured using the Probe Tack Test Method. This method quantifies the moist adhesive energy (mg*cm/cm.sup.2) required to separate two sheets after being pressed together in a moist, foggy localized environment, under prescribed conditions detailed here. A higher Probe Tack measurement predicts a sticky wet experience with the tissue.

[0054] Ply or Plies as used herein means an individual structure comprising one or more webs, optionally to be disposed in a substantially contiguous, face-to-face relationship with other plies, forming a multiple ply fibrous structure. It is also contemplated that a single structure can effectively form two plies or multiple plies, for example, by being folded on itself.

[0055] Fibrous Structure as used herein means a soft, relatively low density structure useful as a wiping implement for post-urinary and post-bowel movement cleaning (toilet tissue), for otorhinolaryngological discharges (facial tissue), multi-functional absorbent and cleaning uses (absorbent towels) and wipes, such as wet and dry wipes. The fibrous structure may be convolutedly wound upon itself about a core or without a core to form a sanitary tissue product roll or may be in the form of discrete sheets.

[0056] Web or Web Material as used herein means a structure that comprises a first web material comprising a plurality of fibrous elements, for example a plurality of fibers, such as a plurality of pulp fibers. In embodiments, the first web may comprise a plurality of wood pulp fibers. In another example, the first web material may comprise a plurality of non-wood pulp fibers, for example plant fibers, synthetic staple fibers, and mixtures thereof. In still another example, in addition to fibers, such as pulp fibers, the first web material may comprise a plurality of filaments, such as polymeric filaments, for example thermoplastic filaments such as polyolefin filaments (i.e., polypropylene filaments), thermoplastic polyvinyl alcohol filaments, and/or hydroxyl polymer filaments, for example polyvinyl alcohol filaments and/or polysaccharide filaments such as starch filaments, such as in the form of a coform web material where the fibers and filaments are commingled together and/or are present as discrete or substantially discrete layers within the first web material. In embodiments, a web material, for example a first web material, according to the present invention means an orderly arrangement of fibers and/or with filaments within a structure in order to perform a function. In embodiments, a fibrous structure according to the present invention means an association of fibrous elements that together form a structure capable of performing a function. In another example of the present invention, a fibrous structure comprises a plurality of inter-entangled fibrous elements, for example inter-entangled filaments. Non-limiting examples of web materials of the present invention include paper.

[0057] Non-limiting examples of processes for making a web material, for example a first web material, of the fibrous structures of the present invention include known wet-laid papermaking processes, for example conventional wet-pressed (CWP) papermaking processes and through-air-dried (TAD), both creped TAD and uncreped TAD, papermaking processes, and air-laid papermaking processes. Such processes typically include steps of preparing a fiber composition in the form of a fiber suspension in a medium, cither wet, more specifically aqueous medium, or dry, more specifically gaseous, i.e. with air as medium. The aqueous medium used for wet-laid processes is oftentimes referred to as a fiber slurry. The fiber slurry is then used to deposit a plurality of the fibers onto a forming wire, fabric, or belt such that an embryonic web material is formed, after which drying and/or bonding the fibers together results in a web material, for example the first web material. Further processing of the first web material may be carried out such that a finished first web material is formed. For example, in typical papermaking processes, the finished first web material is the web material that is wound on the reel at the end of papermaking, often referred to as a parent roll, and may subsequently be converted into a finished fibrous structure of the present invention, e.g. a single- or multi-ply fibrous structure.

[0058] In another example, the web material, for example the first web material is a coformed web material comprising a plurality of filaments and a plurality of fibers commingled together as a result of a coforming process.

[0059] The fibrous structures of the present invention may be homogeneous or may have multiple layers. A layer is a component of a web material that may be created by supplying different fiber streams to different chambers of a stratified headbox and depositing those streams to form a layered web material. U.S. Pat. Nos. 4,300,981 and 3,994,771 disclose different methods of forming layered paper webs. For example, in wet laid structures, a stratified headbox may be supplied with a fiber stream comprising eucalyptus fibers fed a first compartment of the headbox while a different fiber stream comprising a mix of fiber types is fed to a second compartment of the headbox. The first compartment supplies fiber to the surface of the web material that will be the consumer-facing surfacethe surface of the sheet that the consumer will touch when using the product. Layering eucalyptus fibers to the consumer-facing surface can provide softness benefits. In this example the layer is the portion of the web material formed from one compartment of a stratified headbox and the wet laid structure is the web material. Then a second web material, such as a web comprising spun filaments, can be combined with the first web material to create a ply. If layered, the web material may comprise at least two and/or at least three and/or at least four and/or at least five layers of fiber and/or filament compositions

[0060] In embodiments, the fibrous structure of the present invention consists essentially of fibers, for example pulp fibers, such as cellulosic pulp fibers and more particularly wood pulp fibers.

[0061] In another example, the fibrous structure of the present invention comprises fibers and is void of filaments.

[0062] In still another example, the fibrous structures of the present invention comprises filaments and fibers, such as a co-formed fibrous structure.

[0063] Co-formed fibrous structure as used herein means that the fibrous structure comprises a mixture of at least two different materials wherein at least one of the materials comprises a filament, such as a polypropylene filament, and at least one other material, different from the first material, comprises a solid additive, such as a fiber and/or a particulate. In embodiments, a co-formed fibrous structure comprises solid additives, such as fibers, such as wood pulp fibers, and filaments, such as polypropylene filaments.

[0064] Basis Weight as used herein is the weight per unit area of a sample reported in lbs/3000 ft.sup.2 or g/m.sup.2 (gsm) and is measured according to the Basis Weight Test Method described herein.

[0065] Machine Direction or MD as used herein means the direction parallel to the flow of the fibrous structure through a fibrous structure making machine. Typically, the MD is substantially perpendicular to any perforations present in the fibrous structure.

[0066] Cross Machine Direction or CD as used herein means the direction parallel to the width of the fibrous structure making machine and perpendicular to the machine direction in the same plane. Embossed as used herein with respect to a web material or a fibrous structure, means that a web material or a fibrous structure, has been subjected to a process which converts a smooth surfaced web material or fibrous structure to a decorative surface by replicating a design on one or more emboss rolls, which form a nip through which the web material or fibrous structure passes. Embossed does not include creping, microcreping, printing or other processes that may also impart a texture and/or decorative pattern to a web material or a fibrous structure.

[0067] Differential density, as used herein, means a web material that comprises one or more regions of relatively low fiber density, which are referred to as pillow regions, and one or more regions of relatively high fiber density, which are referred to as knuckle regions.

[0068] Densified, as used herein means a portion of a fibrous structure that is characterized by regions of relatively high fiber density (knuckle regions).

[0069] Non-densified, as used herein, means a portion of a fibrous structure that exhibits a lesser density (one or more regions of relatively lower fiber density) (pillow regions) than another portion (for example a knuckle region) of the fibrous structure.

[0070] Non-rolled as used herein with respect to a fibrous structure of the present invention means that the fibrous structure is an individual sheet (for example not connected to adjacent sheets by perforation lines. However, two or more individual sheets may be interleaved with one another) that is not convolutedly wound about a core or itself. For example, a non-rolled product comprises a facial tissue.

[0071] Creped as used herein means creped off of a Yankee dryer or other similar roll and/or fabric creped and/or belt creped. Rush transfer of a fibrous structure alone does not result in a creped fibrous structure for purposes of the present invention.

[0072] The fibrous structures of the present invention may exhibit a basis weight between about 1 g/m.sup.2 to about 5000 g/m.sup.2 and/or from about 10 g/m.sup.2 to about 500 g/m.sup.2 and/or from about 10 g/m.sup.2 to about 300 g/m.sup.2 and/or from about 10 g/m.sup.2 to about 120 g/m.sup.2 and/or from about 15 g/m.sup.2 to about 110 g/m.sup.2 and/or from about 20 g/m.sup.2 to about 100 g/m.sup.2 and/or from about 30 to 90 g/m.sup.2 as determined by the Basis Weight Test Method described herein. In addition, the fibrous structure of the present invention may exhibit a basis weight between about 40 g/m.sup.2 to about 120 g/m.sup.2 and/or from about 50 g/m.sup.2 to about 110 g/m.sup.2 and/or from about 55 g/m.sup.2 to about 105 g/m.sup.2 and/or from about 60 g/m.sup.2 to 100 g/m.sup.2 as determined by the Basis Weight Test Method described herein.

[0073] The fibrous structures of the present invention may exhibit a total dry tensile strength of greater than about 59 g/cm and/or from about 78 g/cm to about 394 g/cm and/or from about 98 g/cm to about 335 g/cm. In addition, the fibrous structure of the present invention may exhibit a total dry tensile strength of greater than about 196 g/cm and/or from about 196 g/cm to about 394 g/cm and/or from about 216 g/cm to about 335 g/cm and/or from about 236 g/cm to about 315 g/cm. In embodiments, the fibrous structure exhibits a total dry tensile strength of less than about 394 g/cm and/or less than about 335 g/cm.

[0074] The fibrous structures of the present invention may exhibit a density of less than 0.60 g/cm.sup.3 and/or less than 0.30 g/cm.sup.3 and/or less than 0.20 g/cm.sup.3 and/or less than 0.15 g/cm.sup.3 and/or less than 0.10 g/cm.sup.3 and/or less than 0.07 g/cm.sup.3 and/or less than 0.05 g/cm.sup.3 and/or from about 0.01 g/cm.sup.3 to about 0.20 g/cm.sup.3 and/or from about 0.02 g/cm.sup.3 to about 0.15 g/cm.sup.3 and/or from about 0.02 g/cm.sup.3 to about 0.10 g/cm.sup.3.

[0075] The fibrous structures of the present invention may be in the form of fibrous structure rolls. Such fibrous structure rolls may comprise a plurality of connected, but perforated sheets of fibrous structure, that are separably dispensable from adjacent sheets.

[0076] The fibrous structures of the present invention may comprise additives such as softening agents, temporary wet strength agents, permanent wet strength agents, bulk softening agents, lotions, silicones, wetting agents, latexes, patterned latexes and other types of additives suitable for inclusion in and/or on fibrous structures.

[0077] Hydroxyl polymer as used herein includes any hydroxyl-containing polymer that can be incorporated into a filament of the present invention. In embodiments, the hydroxyl polymer of the present invention includes greater than 10% and/or greater than 20% and/or greater than 25% by weight hydroxyl moieties. In another example, the hydroxyl within the hydroxyl-containing polymer is not part of a larger functional group such as a carboxylic acid group.

[0078] Non-thermoplastic as used herein means, with respect to a material, such as a fibrous element as a whole and/or a polymer, such as a crosslinked polymer, within a fibrous element, that the fibrous element and/or polymer exhibits no melting point and/or softening point, which allows it to flow under pressure, in the absence of a plasticizer, such as water, glycerin, sorbitol, urea and the like.

[0079] Non-cellulose-containing as used herein means that less than 5% and/or less than 3% and/or less than 1% and/or less than 0.1% and/or 0% by weight of cellulose polymer, cellulose derivative polymer and/or cellulose copolymer is present in fibrous element. In embodiments, non-cellulose-containing means that less than 5% and/or less than 3% and/or less than 1% and/or less than 0.1% and/or 0% by weight of cellulose polymer is present in fibrous element.

[0080] Fast wetting surfactant and/or fast wetting surfactant component and/or fast wetting surfactant function as used herein means a surfactant and/or surfactant component, such as an ion from a fast wetting surfactant, for example a sulfosuccinate diester ion (anion), that exhibits a Critical Micelle Concentration (CMC) of greater 0.15% by weight and/or at least 0.25% and/or at least 0.50% and/or at least 0.75% and/or at least 1.0% and/or at least 1.25% and/or at least 1.4% and/or less than 10.0% and/or less than 7.0% and/or less than 4.0% and/or less than 3.0% and/or less than 2.0% by weight.

[0081] Polymer melt composition or Polysaccharide melt composition as used herein means a composition comprising water and a melt processed polymer, such as a melt processed fibrous element-forming polymer, for example a melt processed hydroxyl polymer, such as a melt processed polysaccharide.

[0082] Melt processed fibrous element-forming polymer as used herein means any polymer, which by influence of elevated temperatures, pressure and/or external plasticizers may be softened to such a degree that it can be brought into a flowable state, and in this condition may be shaped as desired.

[0083] Melt processed hydroxyl polymer as used herein means any polymer that contains greater than 10% and/or greater than 20% and/or greater than 25% by weight hydroxyl groups and that has been melt processed, with or without the aid of an external plasticizer. More generally, melt processed hydroxyl polymers include polymers, which by the influence of elevated temperatures, pressure and/or external plasticizers may be softened to such a degree that they can be brought into a flowable state, and in this condition may be shaped as desired.

[0084] Blend as used herein means that two or more materials, such as a fibrous element-forming polymer, for example a hydroxyl polymer and a polyacrylamide are in contact with each other, such as mixed together homogeneously or non-homogeneously, within a filament. In other words, a filament formed from one material, but having an exterior coating of another material is not a blend of materials for purposes of the present invention. However, a fibrous element formed from two different materials is a blend of materials for purposes of the present invention even if the fibrous element further comprises an exterior coating of a material.

[0085] Associate, Associated, Association, and/or Associating as used herein with respect to fibrous elements and/or with respect to a surface and/or surface material being associated with a fibrous structure and/or a first web material means combining, either in direct contact or in indirect contact, fibrous elements and/or a surface material with a first web material such that a fibrous structure is formed. In embodiments, the associated fibrous elements and/or associated surface material may be bonded to the first web material, directly or indirectly, for example by adhesives and/or thermal bonds to form adhesive sites and/or thermal bond sites, respectively, within the fibrous structure. In another example, the fibrous elements and/or surface material may be associated with the first web material, directly or indirectly, by being deposited onto the same first web material making belt.

[0086] Average Diameter as used herein, with respect to a fibrous element, is measured according to the Average Diameter Test Method described herein. In embodiments, a fibrous element of the present invention exhibits an average diameter of less than 50 m and/or less than 25 m and/or less than 20 m and/or less than 15 m and/or less than 10 m and/or less than 6 m and/or greater than 1 m and/or greater than 3 m.

[0087] 3D Pattern with respect to a fibrous structure's surface in accordance with the present invention means herein a pattern that is present on at least one surface of the fibrous structure. The 3D pattern texturizes the surface of the fibrous structure, for example by providing the surface with protrusions and/or depressions. The 3D pattern on the surface of the fibrous structure is made by making at least one fibrous structure ply on a patterned molding member that imparts the 3D pattern to the fibrous structure plies made thereon. For example, the 3D pattern may comprise a series of line elements, such as a series of line elements that are substantially oriented in the cross-machine direction of the fibrous structure.

[0088] In embodiments, a series of line elements may be arranged in a 3D pattern selected from the group consisting of: periodic patterns, aperiodic patterns, straight line patterns, curved line patterns, wavy line patterns, snaking patterns, square line patterns, triangular line patterns, S-wave patterns, sinusoidal line patterns, and mixtures thereof. In another example, a series of line elements may be arranged in a regular periodic pattern or an irregular periodic pattern (aperiodic) or a non-periodic pattern.

[0089] Wet textured as used herein means that a 3D patterned fibrous structure ply comprises texture (for example a three-dimensional topography) imparted to the fibrous structure and/or fibrous structure's surface during a fibrous structure making process. In embodiments, in a wet-laid fibrous structure making process, wet texture can be imparted to a fibrous structure upon fibers and/or filaments being collected on a collection device that has a three-dimensional (3D) surface which imparts a 3D surface to the fibrous structure being formed thereon and/or being transferred to a fabric and/or belt, such as a through-air-drying fabric and/or a patterned drying belt, comprising a 3D surface that imparts a 3D surface to a fibrous structure being formed thereon. In embodiments, the collection device with a 3D surface comprises a patterned, such as a patterned formed by a polymer or resin being deposited onto a base substrate, such as a fabric, in a patterned configuration. The wet texture imparted to a wet-laid fibrous structure is formed in the fibrous structure prior to and/or during drying of the fibrous structure. Non-limiting examples of collection devices and/or fabric and/or belts suitable for imparting wet texture to a fibrous structure include those fabrics and/or belts used in fabric creping and/or belt creping processes, for example as disclosed in U.S. Pat. Nos. 7,820,008 and 7,789,995, coarse through-air-drying fabrics as used in uncreped through-air-drying processes, and photo-curable resin patterned through-air-drying belts, for example as disclosed in U.S. Pat. No. 4,637,859. For purposes of the present invention, the collection devices used for imparting wet texture to the fibrous structures would be patterned to result in the fibrous structures comprising a surface pattern comprising a plurality of parallel line elements wherein at least one, two, three, or more, for example all of the parallel line elements exhibit a non-constant width along the length of the parallel line elements. This is different from non-wet texture that is imparted to a fibrous structure after the fibrous structure has been dried, for example after the moisture level of the fibrous structure is less than 15% and/or less than 10% and/or less than 5%. An example of non-wet texture includes embossments imparted to a fibrous structure by embossing rolls during converting of the fibrous structure.

[0090] As used herein, the term geometric mean tensile (GMT) refers to the square root of the product of the machine direction tensile and the cross-machine direction tensile of the web, which are determined as described in the Test Method section.

[0091] As used herein, the term caliper is the representative thickness of a single sheet (caliper of fibrous structures comprising two or more plies is the thickness of a single sheet of fibrous structure comprising all plies) measured in accordance with TAPPI test method T402 using an EMVECO 200-A Microgage automated micrometer (EMVECO, Inc., Newberg, Oreg.). The micrometer has an anvil diameter of 2.22 inches (56.4 mm) and an anvil pressure of 132 grams per square inch (per 6.45 square centimeters) (2.0 kPa).

[0092] As used herein, the term slope refers to slope of the line resulting from plotting tensile versus stretch and is an output of the MTS TestWorks while determining the tensile strength as described in the Test Methods section herein. Slope is reported in the units of grams (g) per unit of sample width (inches) and is measured as the gradient of the least-squares line fitted to the load-corrected strain points falling between a specimen-generated force of 70 to 157 grams (0.687 to 1.540 N) divided by the specimen width. Slopes are generally reported herein as having units of grams per 3 inch sample width or g/3.

[0093] As used herein, the term geometric mean slope (GM Slope) generally refers to the square root of the product of machine direction slope and cross-machine direction slope.

[0094] As used herein, the term stretch generally refers to the ratio of the slack-corrected elongation of a specimen at the point it generates its peak load divided by the slack-corrected gauge length in any given orientation. Stretch is an output of the MTS TestWorks while determining the tensile strength as described in the Test Methods section herein. Stretch is reported as a percentage and may be reported for machine direction stretch (MDS), cross-machine direction stretch (CDS) or as geometric mean stretch (GMS), which is the square root of the product of machine direction stretch and cross-machine direction stretch.

[0095] As used herein, the term Roll Firmness, generally refers to the ability of a rolled fibrous structure to withstand deflection when impacted, which is determined as described in the Test Methods section.

[0096] As used herein, the term Roll Structure generally refers to the overall appearance and quality of a rolled fibrous structure and is the product of Roll Bulk (expressed in cc/g) and caliper (express in cm) divided by Firmness (expressed in cm). Roll Structure is generally referred to herein without reference to units.

[0097] As used herein, the term Stiffness Index refers to the quotient of the geometric mean slope (having units of g/3) divided by the geometric mean tensile strength (having units of g/3).

[0098] As used herein, the term Surface Smoothness refers to the filtered surface image topography measured as described in the Test Method section. Surface Smoothness is expressed as three different valuesSa, Sq and S90and may have units of millimeters (mm) or microns (m).

[0099] Because of the relationship between surface topography and perceived smoothness or roughness, the relative feel of a fibrous structure may be predicted based upon its surface topography. Surface topography may be measured using profilometry, for example by the Smoothness Test Method set forth below. Profilometry is used to generate a digital image of the fibrous structure surface. The digital image is then filtered using a band pass filter with cut off spatial frequencies of 0.095 mm and 0.5 mm to emphasize spatial frequencies experienced as being most rough by the human fingertip. The filtered surface image is then analyzed to yield Surface Smoothness values Sa, Sq and S90, where surfaces having lower values are generally perceived as being smoother.

[0100] Accordingly, in certain embodiments, fibrous structures of the Present Invention have improved smoothness, such as low Sa, Sq and/or S90 values, while also having improved sheet caliper and bulk. For example, in one embodiment the disclosure provides a Present Invention having a Surface Smoothness Sa value less than about 25 m, an Sq value of less than about 35 m, an S90 value less than about 105 m and a sheet bulk of greater than 15 cc/g. In other embodiments the disclosure provides a fibrous structure having a Surface Smoothness Sa value from about 15 to about 25 m. In other embodiment the disclosure provides a fibrous structure having a Surface Smoothness Sq value from about 25 to about 40 m. In still other embodiments the disclosure provides a fibrous structure having a Surface Smoothness S90 value from about 70 to about 120 m.

[0101] As used herein, the articles a and an when used herein, for example, an anionic surfactant or a fiber is understood to mean one or more of the material that is claimed or described.

[0102] All percentages and ratios are calculated by weight unless otherwise indicated. All percentages and ratios are calculated based on the total composition unless otherwise indicated.

[0103] Unless otherwise noted, all component or composition levels are in reference to the active level of that component or composition, and are exclusive of impurities, for example, residual solvents or by-products, which may be present in commercially available sources.

Fibrous Structures

[0104] In embodiments of the present invention as shown in FIGS. 1 and 2, a fibrous structure 10 of the present invention comprises a first web material 12 comprising a plurality of fibrous elements, for example fibers 14, and a surface material 16, for example a second web material 18 comprising a plurality of fibrous elements, for example spun fibrous elements and/or non-naturally occurring fibrous elements, such as filaments 20, for example hydroxyl polymer filaments, such that the fibrous structure exhibits improved surface smoothness, low lint, good wet feel and low wet tack/cold water solubility, for example known fibrous structures, such as known toilet tissue products and/or known skin-wiping fibrous structure products.

[0105] In embodiments, the surface material 16 comprises a plurality of fibers and/or filaments that are deposited onto the first web material 12 in a layered configuration. The surface material 16 may be in the form of a second web material 18 after being deposited onto the first web material 12.

[0106] In another embodiment, the surface material 16 comprises a pre-formed second web material 18 that is associated with a first web material 12 in a multi-ply configuration.

[0107] In embodiments, as shown in FIG. 2, a surface 22 of the surface material 16 may be a consumer-contacting surface, such that during use of the fibrous structure 10 the consumer wipes the surface 22 of the surface material 16, such as the second web material 18, across the skin of the consumer or another person. One of the benefits of the fibrous structure 10 is that it exhibits improved cold-water solubility and acceptable wet feel/low wet tack.

[0108] In embodiments, the surface material 16, for example second web material 18, may be associated with the first web material 12 by bonding via bond sites, such as thermal bond sites 24.

[0109] As shown in FIG. 3, in embodiments a multi-ply fibrous structure 26 may comprise a first fibrous structure ply 28 and a second fibrous structure ply 30 wherein at least one of the first and second fibrous structure plies 28, 30 is a fibrous structure 10 according to the present invention. In this case, both the first and second fibrous structure plies 28, 30 are fibrous structures 10 according to the present invention. The first and second fibrous structure plies 28, 30 may be associated with one another by bonding, such as thermal bond sites and/or adhesive bond sites 32 as shown. The first and second fibrous structure plies 28, 30 are associated with one another such that the surface material 16 of both the first and second fibrous structure plies 28, 30 form exterior surfaces of the multi-ply fibrous structure 26 and the first web material 12 of both the first and second fibrous structure plies 28, 30 form inner web materials within the multi-ply fibrous structure 26.

[0110] In embodiments, a multi-ply fibrous structure 26 according to the present invention may comprise a first fibrous structure ply 28 and a second fibrous structure ply 30, which may be glued together by adhesive bond sites 32 to form the multi-ply fibrous structure 26. The first fibrous structure ply 28 comprises an exterior layer, the surface material 16, for example the second web material 18, comprising a plurality of fibrous elements, for example a plurality of filaments 20, such as hydroxyl polymer filaments, for example blended PVOH filaments, and an additional layer, the first web material 12, which comprises a plurality of fibrous elements, for example a plurality of fibers, such as pulp fibers, for example wood pulp fibers, present at a level of greater than about 0.30 gsm to about 3.0 gsm, greater than 6 gsm and/or greater than 8 gsm and/or greater than greater than 10 gsm and/or greater than 12 gsm and/or greater than 14 gsm and/or greater than 16 gsm and/or at least 18 gsm and/or less than 55 gsm and/or less than 50 gsm and/or less than 40 gsm and/or less than 35 gsm.

[0111] As shown in FIG. 4, in another example of the present invention, the fibrous structure 10 comprises one or more voids 34 (vacuoles) defined by two different materials, for example both the surface material 16 and the first web material 12. A void 34 may be formed by the surface material 16 bridging a texture, such as a depression or channel, such as imparted to a surface of the first web material 12 by a patterned molding member, for example a patterned resin molding member and/or a through-air-drying fabric, such as a coarse through-air-drying fabric, for example as is used in the UCTAD process, and/or an embossing operation and/or a creping operation, such as a belt creping operation and/or a fabric creping operation and/or creping off a drying cylinder, such as a Yankee. The voids 34 of the fibrous structures 10 may be seen using different imaging tools, such as CT.

[0112] As also shown in FIG. 4, the fibrous structure 10 of the present invention may comprise differential planar materials relative to each other, for example a monoplanar material, for example the surface material 16, and a multi-planar material, for example the first web material 12 that comprises a texture.

[0113] In embodiments, the surface material 16 may comprise a water soluble polymer, such as a semi-crystalline polymer, for example starch and/or starch derivative and/or polyvinylalcohol, and the first web material 12 may comprise a water insoluble polymer, such as a highly crystalline polymer, for example cellulose.

[0114] In another example, the surface material 16, for example the second web material 18 may comprise a plurality of fibrous elements, for example a plurality of smooth fibrous elements, such as smooth spun filaments, in other words, the exterior surface of the fibrous elements is non-textured, at least relative to the fibrous elements of the first web material 12, for example pulp fibers, such as wood pulp fibers, which are textured (rough) relative to the smooth fibrous elements of the second web material 18.

[0115] In still another example, the surface material 16, for example the second web material 18 may comprise a plurality of fibrous elements, for example filaments 20, that exhibit an average diameter (less than 10 m) less than the average diameter (greater than 10 m and/or greater than 12 m) of the fibrous elements, for example fibers 14, such as pulp fibers, of the first web material 12.

[0116] In still yet another example, the surface material 16, for example the second web material 18 may comprise a plurality of fibrous elements, for example filaments 20, that exhibit a length (greater than 5.08 cm) greater than the length (5.08 cm or less) of the fibrous elements, for example fibers 14, such as pulp fibers, of the first web material 12.

[0117] In embodiments, the fibrous structure 10 of the present invention may be made by the fibrous structure making process 40 shown in FIG. 5 by providing a first web material 12 comprising a plurality of fibrous elements, for example fibers 14, and depositing a surface material 16, for example a plurality of fibrous elements, for example filaments 20, from one or more surface material sources 21, such as a die, for example a meltblow die, such as a multi-row capillary die as shown in FIG. 6 in this case to form a second web material 18 of inter-entangled fibrous elements, for example filaments 20, onto at least one surface of the first web material 12 to form the fibrous structure 10 of the present invention. When a second surface material is applied to the fibrous structure 10, at least one of the surface material sources 21 deposits the second surface material, such that the first surface material is positioned between the first web material 12 and the second surface material. The fibrous structure making process 40 may further comprise the step of associating the surface material 16 to the first web material 12 such as by bonding, for example creating thermal bond sites 24 by passing the surface material 16 riding on the first web material 12 through a nip 36 formed a patterned thermal bond roll 38 and an flat roll 39. The fibrous structure making process 40 may optionally comprise the step of winding the fibrous structure 10 into a roll, such as a parent roll for unwinding in a converting operation to cut the roll into consumer-useable sized fibrous structure rolls and/or emboss the fibrous structure and/or perforate the fibrous structure into consumer-useable sized sheets of fibrous structure. In addition, the roll of fibrous structure may be combined with another fibrous structure ply, the same or different as the roll of fibrous structure to make a multi-ply fibrous structure 26 according to the present invention, an example of which is shown in FIG. 3.

[0118] The multi-row capillary die (surface material source 21) shown in FIG. 6 comprises at least one fibrous element-forming hole 23, and/or 2 or more and/or 3 or more rows of fibrous element-forming holes 23 from which filaments are spun. At least one row of the fibrous element-forming holes 23 contains 2 or more and/or 3 or more and/or 10 or more fibrous element-forming holes 23. In addition to the fibrous element-forming holes 23, the multi-row capillary die comprises fluid-releasing holes 25, such as gas-releasing holes, in embodiments air-releasing holes, that provide attenuation to the filaments formed from the fibrous element-forming holes 23. One or more fluid-releasing holes 25 may be associated with a fibrous element-forming hole 23 such that the fluid exiting the fluid-releasing hole 25 is parallel or substantially parallel (rather than angled like a knife-edge die) to an exterior surface of a filament exiting the fibrous element-forming hole 23. In embodiments, the fluid exiting the fluid-releasing hole 25 contacts the exterior surface of a filament formed from a fibrous element-forming hole 23 at an angle of less than 30 and/or less than 20 and/or less than 10 and/or less than 5 and/or about 0. One or more fluid releasing holes 25 may be arranged around a fibrous element-forming hole 23. In embodiments, one or more fluid-releasing holes 25 are associated with a single fibrous element-forming hole 23 such that the fluid exiting the one or more fluid releasing holes 25 contacts the exterior surface of a single filament formed from the single fibrous element-forming hole 23. In embodiments, the fluid-releasing hole 25 permits a fluid, such as a gas, for example air, to contact the exterior surface of a filament formed from a fibrous element-forming hole 23 rather than contacting an inner surface of a filament, such as what happens when a hollow filament is formed.

[0119] In embodiments, one or more plies of the fibrous structure according to the present invention may be combined, for example with glue, with another ply of fibrous structure, which may also be a fibrous structure according to the present invention, to form a multi-ply fibrous structure. In embodiments, the multi-ply fibrous structure may be formed by combining two or more plies of fibrous structure according to the present invention.

[0120] The fibrous structures of the blended PVOH in the present invention have a combination of unique properties of cold-water solubility, % crystallinity, low wet tack, and good surface feel. TS7 values as measured by Emtec Test Method are less than 7.9 Hz, wet tack values as measured by the Wet Tack Test Method are less than 9500 mg/cm, the % crystallinity is less than 40% as measured by the Differential Scanning calorimetry Test Method, and the fibers are cold-water soluble and exhibit no residual microstructure as measured by the Cold-Water Solubility Test Method.

[0121] Surprisingly, blending two different hydrolysis levels of PVOH results in an average hydrolysis level, which is more effective at reducing crystallinity and increasing cold water solubility compared to a single PVOH grade that has the same hydrolysis level. Not to be bound by theory, but it is believed because PVOH chains are known to have blocky segments of hydroxyl groups, these segments can more readily associate, form hydrogen bonds, and create crystalline domains. By introducing a second PVOH grade of dissimilar hydroxyl content that is intimately mixed with the first grade, the acetate groups of the second component can disrupt interactions between the blocky hydroxyl groups of the first component. FIG. 12 compares the crystallinity of a single PVOH spun fiber (blue) to a blended PVOH spun fiber (green) where the blended hydrolysis level is average value between the two single components. In the 90 to 96% hydroxyl range, the % crystallinity is significantly lower for a blend compared to a pure PVOH material at a constant hydrolysis level due to the former's ability to prevent hydrogen bonding between the blocky hydroxyl segments.

[0122] In another example, the fibrous structures of the present invention may be creped or uncreped. In embodiments, the fibrous structures of the present invention are uncreped fibrous structures. In embodiments, the exterior surface of the fibrous structure of the present invention, for example surface 22 of the surface material 16 is not creped (uncreped and/or non-undulating and/or not creped off a surface, such as a Yankee), however the first web material 12 may be creped (undulating and/or creped off a surface, such as a Yankee).

[0123] In addition to the fibrous structures of the present invention exhibiting improved surface properties as described herein, such fibrous structures also may exhibit improved cleaning properties, for example bowel movement cleaning properties, compared to known fibrous structures, for example known fibrous structures comprising hydroxyl polymer filaments and known fibrous structures, such as wet-laid and/or air-laid, comprising cellulose fibers, for example pulp fibers. Without wishing to be bound by theory, it is believed that the fibrous structures of the present invention exhibit improved skin benefit and/or glide on skin properties and/or cleaning properties due to the hydroxyl polymer fibrous elements of the present invention exhibiting greater absorbency, without a gooey feel, than pulp fibers, and therefore facilitates better, in reality and/or perception, absorption of bowel movement and/or urine more completely and/or faster than known fibrous structures. In addition, it is believed that the fibrous structures of the present invention that comprise a plurality of hydroxyl polymer fibrous elements, for example hydroxyl polymer filaments in an exterior layer, such as a scrim, provides an improved adsorbency, without a gooey feel, than known fibrous structures, such that the hydroxyl polymer fibrous elements during use contact the user's skin surface and trap and/or lock in the bowel movement or portions thereof.

[0124] Further, it is believed that the fibrous structures of the present invention that comprise a plurality of hydroxyl polymer fibrous elements, for example hydroxyl polymer filaments in an exterior layer that provide improved surface properties permits a user to apply more force to the fibrous structure during use because the hydroxyl polymer fibrous elements provide a cushion and/or buffer compared to known fibrous structures, especially known wet-laid and/or air-laid fibrous structures that consist or consist essentially of pulp fibers.

[0125] The fibrous structures of the present invention may be embossed and/or tufted that creates a three-dimensional surface pattern that provides aesthetics and/or improved cleaning properties. The level of improved cleaning properties relates to the % contact area under a load, such as a user's force applied to the fibrous structure during wiping, and/or % volume/area under a load, such as a user's force applied to the fibrous structure during wiping, created by the three-dimensional surface pattern on the surface of the fibrous structure. In embodiments, the emboss area may be greater than 10% and/or greater than 12% and/or greater than 15% and/or greater than 20% of the surface area of at least one surface of the fibrous structure.

[0126] The fibrous structure of the present invention may also exhibit a Force to Drag Value of less than 85 and/or less than 80 and/or less than 75 and/or less than 70 and/or less than 65 and/or less than 63 and/or less than 60 and/or less than 55 and/or less than 50 as measured according to the Glide on Skin Test Method described herein.

[0127] The fibrous structure of the present invention may also exhibit an CRT Initial Rate at 2 Seconds of greater than 0.50 and/or greater than 0.75 and/or greater than 1.00 and/or greater than 1.25 and/or greater than 1.50 and/or greater than 2.00 and/or greater than 2.25 and/or greater than 2.40 g/2 seconds as measured according to the CRT Test Method described herein.

[0128] The fibrous structure of the present invention may comprise two or more components, for example a first component comprising a first web material that exhibits a different bulk density from the second component, such as a the surface material. In embodiments, the first web material exhibits a lower bulk density than the surface material, for example second web material as determined according to the CT (Micro-CT) Test Method described herein.

[0129] The fibrous structure comprises a least one surface, a consumer-contacting surface, that comes into contact with a consumer during use, such as during wiping. The surface of the fibrous structure may comprise and/or be defined by at least a portion of the first web material.

[0130] In embodiments, the fibrous structure of the present invention is a layered (as used herein layered in this context means the fibrous structure is not made up of separate plies of fibrous structures or web materials that are associated with one another to form a multi-ply fibrous structure, but rather is made up of a first web material upon which a surface material (not in the form of a pre-formed web material, but rather in the form of fibrous elements) is deposited, directly or indirectly, onto the first web material), and optionally dispersible (as used herein dispersible means aerobic biodisintegratable as measured according to EDANA FG505 Aerobic Biodisintegration Test) fibrous structure.

[0131] In embodiments, the fibrous structure is a wet fibrous structure, for example a fibrous structure comprising a liquid composition.

First Web Material

[0132] The first web material comprises a plurality of fibrous elements, for example a plurality of fibers, such as greater than 80% and/or greater than 90% and/or greater than 95% and/or greater than 98% and/or greater than 99% and/or 100% by weight of the first web material of fibers.

[0133] In embodiments, the first web material comprises a plurality of naturally-occurring fibers, for example pulp fibers, such as wood pulp fibers (hardwood and/or softwood pulp fibers). In another example, the first web material comprises a plurality of non-naturally occurring fibers (synthetic fibers), for example staple fibers, such as rayon, lyocell, polyester fibers, polycaprolactone fibers, polylactic acid fibers, polyhydroxyalkanoate fibers, and mixtures thereof. In another example, the first web material comprises a mixture of naturally-occurring fibers, for example pulp fibers, such as wood pulp fibers (hardwood and/or softwood pulp fibers) and a plurality of non-naturally occurring fibers (synthetic fibers), for example staple fibers, such as rayon, lyocell, polyester fibers, polycaprolactone fibers, polylactic acid fibers, polyhydroxyalkanoate fibers, and mixtures thereof.

[0134] The first web material may comprise one or more filaments, such as polyolefin filaments, which are not dispersible, for example polypropylene and/or polyethylene filaments, starch filaments, starch derivative filaments, cellulose filaments, polyvinyl alcohol filaments.

[0135] The first web material of the present invention may be single-ply or multi-ply web material. In other words, the first web materials of the present invention may comprise one or more first web materials, the same or different from each other so long as one of them comprises a plurality of pulp fibers.

[0136] In embodiments, the first web material comprises a wet laid fibrous structure ply, such as a through-air-dried fibrous structure ply, for example an uncreped, through-air-dried fibrous structure ply and/or a creped, through-air-dried fibrous structure ply.

[0137] In another example, the first web material and/or wet laid fibrous structure ply may exhibit substantially uniform density.

[0138] In another example, the first web material and/or wet laid fibrous structure ply may exhibit differential density.

[0139] In another example, the first web material and/or wet laid fibrous structure ply may comprises a surface pattern

[0140] In embodiments, the wet laid fibrous structure ply comprises a conventional wet-pressed fibrous structure ply. The wet laid fibrous structure ply may comprise a fabric-creped fibrous structure ply. The wet laid fibrous structure ply may comprise a belt-creped fibrous structure ply.

[0141] In still another example, the first web material may comprise an air laid fibrous structure ply.

[0142] The first web materials of the present invention may comprise a surface softening agent or be void of a surface softening agent, such as silicones, quaternary ammonium compounds, lotions, and mixtures thereof. In embodiments, the fibrous structure is a non-lotioned first web material.

[0143] The first web materials of the present invention may comprise trichome fibers or may be void of trichome fibers.

Non-limiting Examples of Making First Web Materials

[0144] The first web materials of the present invention may be made by any suitable papermaking process, such as conventional wet press papermaking process, through-air-dried papermaking process, belt-creped papermaking process, fabric-creped papermaking process, creped papermaking process, uncreped papermaking process, coform process, and air-laid process, so long as the first web material comprises a plurality of fibers. In embodiments, the first web material is made on a molding member of the present invention is used to make the first web material of the present invention. The method may be a first web material making process that uses a cylindrical dryer such as a Yankee (a Yankee-process) or it may be a Yankeeless process as is used to make substantially uniform density and/or uncreped first web materials (fibrous structures). Alternatively, the first web materials may be made by an air-laid process and/or meltblown and/or spunbond processes and any combinations thereof so long as the first web materials of the present invention are made thereby.

[0145] As shown in FIG. 10, one example of a process and equipment, represented as 66 for making a first web material according to the present invention comprises supplying an aqueous dispersion of fibers (a fibrous furnish or fiber slurry) to a headbox 68 which can be of any convenient design. From headbox 68 the aqueous dispersion of fibers is delivered to a first foraminous member 70 which is typically a Fourdrinier wire, to produce an embryonic fibrous structure 72.

[0146] The first foraminous member 70 may be supported by a breast roll 74 and a plurality of return rolls 76 of which only two are shown. The first foraminous member 70 can be propelled in the direction indicated by directional arrow 78 by a drive means. Optional auxiliary units and/or devices commonly associated fibrous structure making machines and with the first foraminous member 70, include forming boards, hydrofoils, vacuum boxes, tension rolls, support rolls, wire cleaning showers, and the like.

[0147] After the aqueous dispersion of fibers is deposited onto the first foraminous member 70, embryonic fibrous structure 72 is formed, typically by the removal of a portion of the aqueous dispersing medium by techniques well known to those skilled in the art. Vacuum boxes, forming boards, hydrofoils, and the like are useful in effecting water removal. The embryonic web material 72 may travel with the first foraminous member 70 about return roll 76 and is brought into contact with a patterned molding member 50, such as a 3D patterned through-air-drying belt. While in contact with the patterned molding member 50, the embryonic web material 72 will be deflected, rearranged, and/or further dewatered. This can be accomplished by applying differential speeds and/or pressures.

[0148] The patterned molding member 50 may be in the form of an endless belt. In this simplified representation, the patterned molding member 50 passes around and about patterned molding member return rolls 82 and impression nip roll 84 and may travel in the direction indicated by directional arrow 86. Associated with patterned molding member 50, but not shown, may be various support rolls, other return rolls, cleaning means, drive means, and the like well known to those skilled in the art that may be commonly used in fibrous structure making machines.

[0149] After the embryonic web material 72 has been associated with the patterned molding member 50, fibers within the embryonic web material 72 are deflected into pillows (deflection conduits) present in the patterned molding member 50. In embodiments of this process step, there is essentially no water removal from the embryonic web material 72 through the deflection conduits after the embryonic web material 72 has been associated with the patterned molding member 50 but prior to the deflecting of the fibers into the deflection conduits. Further water removal from the embryonic web material 72 can occur during and/or after the time the fibers are being deflected into the deflection conduits. Water removal from the embryonic web material 72 may continue until the consistency of the embryonic web material 72 associated with patterned molding member 50 is increased to from about 25% to about 35%. Once this consistency of the embryonic web material 72 is achieved, then the embryonic web material 72 can be referred to as an intermediate web material 88. During the process of forming the embryonic web material 72, sufficient water may be removed, such as by a non-compressive process, from the embryonic web material 72 before it becomes associated with the patterned molding member 50 so that the consistency of the embryonic web material 72 may be from about 10% to about 30%.

[0150] As noted, water removal occurs both during and after deflection; this water removal may result in a decrease in fiber mobility in the embryonic web material. This decrease in fiber mobility may tend to fix and/or freeze the fibers in place after they have been deflected and rearranged. The drying of the web material in a later step in the process of this invention may serve to more firmly fix and/or freeze the fibers in position.

[0151] Any convenient means conventionally known in the papermaking art can be used to dry the intermediate web material 88. Examples of such suitable drying process include subjecting the intermediate web material 88 to conventional and/or flow-through dryers and/or Yankee dryers.

[0152] In embodiments of a drying process, the intermediate web material 88 in association with the patterned molding member 50 passes around one or more patterned molding member return rolls 82 and travels in the direction indicated by directional arrow 86. The intermediate web material 88 may pass through an optional predryer 90. This predryer 90 can be a conventional flow-through dryer (hot air dryer) well known to those skilled in the art. In addition, the predryer 90 can also be a so-called capillary dewatering apparatus. In such an apparatus, the intermediate web material 88 passes over a sector of a cylinder having preferential-capillary-size pores through its cylindrical-shaped porous cover. Further, the predryer 90 can be a combination capillary dewatering apparatus and flow-through dryer. The quantity of water removed in the predryer 90 may be controlled so that a predried web material 92 exiting the predryer 90 has a consistency (percent solids in the sheet-a measure of dryness) of from about 30% to about 98%. The predried web material 92, which may still be associated with patterned molding member 50, may pass around another patterned molding member return roll 82 and as it travels to an impression nip roll 84. As the predried web material 92 passes through the nip formed between impression nip roll 84 and a surface of a Yankee dryer 94, the pattern formed by the top surface 96 of patterned molding member 50 is impressed into the predried web material 92 to form a 3D patterned web material 98, a first web material of the present invention. The 3D patterned web material 98 can then be adhered to the surface of the Yankee dryer 94 where it can be dried to a consistency of at least about 95%.

[0153] The 3D patterned web material 98 can then be foreshortened by creping (creped off the Yankee) the 3D patterned web material 98 with a creping blade 97 to remove the 3D patterned web material 98 from the surface of the Yankee dryer 94 resulting in the production of a 3D patterned creped web material 99, which is a non-limiting example of a first web material in accordance with the present invention. As used herein, foreshortening refers to the reduction in length, in the machine direction, of a dry (having a consistency of at least about 90% and/or at least about 95%) web material which occurs when energy is applied to the dry web material in such a way that the length of the dry web material is reduced and the fibers in the dry web material are rearranged with an accompanying disruption of fiber-fiber bonds. Foreshortening can be accomplished in any of several well-known ways. One common method of foreshortening is creping. Further, the 3D patterned creped web material 99 may be subjected to post processing steps such as calendaring, tuft generating operations, and/or embossing and/or converting.

Surface Material

[0154] In addition to the first web material, the fibrous structure of the present invention includes a surface material comprising cold water soluble PVOH fibrous elements. The surface material of the fibrous structure is different from the first web material. The surface material may be associated with the first web material, directly (meaning in direct contact with a surface of the first web material) and/or indirectly (meaning one or more intermediate materials are positioned between the surface of the first web material and the surface material. In embodiments, the surface material is associated with the first web material through one or more bond sites, for example at least one of the bond sites comprise a thermal bond and/or at least one of the bond sites comprises an adhesive bond. In another example, the surface material may be indirectly bonded to a surface of the first web material by being bonded to one or more intermediate materials positioned between the surface of the first web material and the surface material. The intermediate materials may be fibrous elements, web materials, liquids, particles, and/or surface coatings, such as surface softening agents, present on the surface of the first web material.

Fibrous Elements

[0155] The fibrous elements of the present invention, including cold water soluble PVOH fibrous elements may be produced from a blended polymer melt composition, for example a blended hydroxyl polymer melt composition such as a blended aqueous hydroxyl polymer melt composition, comprising a hydroxyl polymer, such as a polyvinyl alcohol where one polyvinyl alcohol has a medium hydrolysis content and one polyvinyl alcohol as a high hydrolysis content.

[0156] The fibrous elements are composed of a blended PVOH fiber composition comprising a first medium level of hydrolysis of about 70% to about 90% and a second PVOH having a high level of hydrolysis between about 92% and about 99%. The amount of the first PVOH is between about 35% to about 75% and the amount of the second PVOH is between about 25% to 65% based on the weight of the blended fibrous element. The blended PVOH fibrous elements have a crystalline content between about 20% to about 50%.

[0157] In embodiments, the fibrous element of the present invention is void of thermoplastic, water-insoluble polymers.

[0158] In embodiments, the fibrous element-forming polymers may be present in the aqueous hydroxyl polymer melt composition at an amount of from about 20% to about 50% and/or from about 30% to about 50% and/or from about 35% to about 48% by weight of the aqueous hydroxyl polymer melt composition and present in a polymeric structure, for example fibrous element and/or fibrous structure, at a level of from about 50% to about 100% and/or from about 60% to about 98% and/or from about 75% to about 95% by weight of the polymeric structure, for example fibrous element and/or fibrous structure.

Polymer Melt Composition

[0159] The polymer melt composition, for example an aqueous polymer melt composition such as an aqueous hydroxyl polymer melt composition, of the present invention comprises a melt processed fibrous element-forming polymer, such as a melt processed hydroxyl polymer, and a fast wetting surfactant according to the present invention.

[0160] The polymer melt compositions may already be formed or a melt processing step may need to be performed to convert a raw material fibrous element-forming polymer, such as a hydroxyl polymer, into a melt processed fibrous element-forming polymer, such as a melt processed hydroxyl polymer, thus producing the polymer melt composition. Any suitable melt processing step known in the art may be used to convert the raw material fibrous element-forming polymer into the melt processed fibrous element-forming polymer. Melt processing as used herein means any operation and/or process by which a polymer is softened to such a degree that it can be brought into a flowable state.

[0161] The polymer melt compositions may have a temperature of from about 50 C. to about 100 C. and/or from about 65 C. to about 95 C. and/or from about 70 C. to about 90 C. when spinning fibrous elements from the polymer melt compositions.

[0162] In embodiments, the polymer melt composition of the present invention may comprise from about 30% and/or from about 40% and/or from about 45% and/or from about 50% to about 75% and/or to about 80% and/or to about 85% and/or to about 90% and/or to about 95% and/or to about 99.5% by weight of the polymer melt composition of a fibrous element-forming polymer, such as a hydroxyl polymer. The fibrous element-forming polymer, such as a hydroxyl polymer, may have a weight average molecular weight greater than 10,000 g/mol.

[0163] The fibrous elements of the present invention may include melt spun fibers and/or spunbond fibers, staple fibers, hollow fibers, shaped fibers, such as multi-lobal fibers and multicomponent fibers, especially bicomponent fibers. The multicomponent fibers, especially bicomponent fibers, may be in a side-by-side, sheath-core, segmented pie, ribbon, islands-in-the-sea configuration, or any combination thereof. The sheath may be continuous or non-continuous around the core. The ratio of the weight of the sheath to the core can be from about 5:95 to about 95:5. The fibers of the present invention may have different geometries that include round, elliptical, star shaped, rectangular, and other various eccentricities.

[0164] In embodiments, the fibrous structures of the present invention comprise a plurality of fibrous elements, for example hydroxyl polymer filaments comprising a hydroxyl polymer. In another example, the fibrous structures may comprise starch and/or starch derivative filaments. The starch filaments may further comprise polyvinyl alcohol and/or other polymers.

Non-Limiting Example of a Fibrous Structure

[0165] A polymer melt composition comprising 70% Poval 5-88 and 30% Poval 4-98 commercially available from Kuraray Co. Ltd., Tokyo, Japan, is mixed with water and extruded from a co-rotating twin screw extruder at approximately 50% solids. The aqueous blended PVOH melt composition reaches a peak temperature of 170 C. at the exit of the extruder, and then passes through a static mixer where the melt composition is further diluted with water to 42% solids. The melt composition is then metered to a melt blown spinneret (melt blowing die) and attenuated with 65 C. saturated air stream. The filaments are dried in the spin line using 232 C. convective drying air to form a nonwoven layer of blended PVOH filaments with a basis weight between 1.0 and 2.0 g/m.sup.2. The filaments are directly spun and deposited on a first web material (a pre-formed cellulosic web) to form a fibrous structure according to the present invention. The meltblown filaments in the fibrous structure are essentially continuous filaments.

[0166] The first web material (pre-formed cellulosic web) of the fibrous structure has a basis weight of from about 10 gsm to about 50 gsm. It is produced from a wet laid papermaking process commonly known in the art. The cellulosic web can be made creped or uncreped, patterned or unpatterned.

[0167] The fibrous structure is then subjected to a thermal bonding process wherein the thermal bond sites are formed with heat and pressure. The fibrous structure is then rewond into a single ply parent roll.

[0168] The single ply parent roll is then converted into a fibrous structure with perforations and an emboss pattern. Alternatively, two parent rolls may be used to convert into a 2 ply fibrous structure.

Test Methods

[0169] Unless otherwise specified, all tests described herein including those described under the Definitions section and the following test methods are conducted on samples that have been conditioned in a conditioned room at a temperature of 23 C.1.0 C. and a relative humidity of 50%+2% for a minimum of 24 hours prior to the test. All plastic and paper board packaging articles of manufacture, if any, must be carefully removed from the samples prior to testing. The samples tested are usable units. Usable units as used herein means sheets, flats from roll stock, pre-converted flats, fibrous structure, and/or single or multi-ply products. Except where noted all tests are conducted in such conditioned room, all tests are conducted under the same environmental conditions and in such conditioned room. Discard any damaged product. Do not test samples that have defects such as wrinkles, tears, holes, and like. All instruments are calibrated according to manufacturer's specifications.

Basis Weight Test Method

[0170] Basis weight of a fibrous structure is measured on stacks of twelve usable units using a top loading analytical balance with a resolution of +0.001 g. The balance is protected from air drafts and other disturbances using a draft shield. A precision cutting die, measuring 8.890 cm0.00889 cm by 8.890 cm0.00889 cm is used to prepare all samples.

[0171] With a precision cutting die, cut the samples into squares. Combine the cut squares to form a stack twelve samples thick. Measure the mass of the sample stack and record the result to the nearest 0.001 g.

[0172] The Basis Weight is calculated in g/m.sup.2 as follows:

Basis Weight=(Mass of stack)/[(Area of 1 square in stack)(No. of squares in stack)]

Basis Weight (g/m.sup.2)=Mass of stack (g)/[79.032 (cm.sup.2)/10,000 (cm.sup.2/m.sup.2)12]

[0173] Report result to the nearest 0.1 g/m.sup.2. Sample dimensions can be changed or varied using a similar precision cutter as mentioned above, so as at least 645 square centimeters of sample area is in the stack.

Average Diameter Test Method

[0174] This Average Diameter Test Method is used to determine the average diameters of fibrous elements, such as filaments and/or fibers, where their known average diameters are not already known. For example, average diameters of commercially available fibers, such as rayon fibers, have known lengths whereas average diameters of spun filaments, such as spun hydroxyl polymer filaments, would be determined as set forth immediately below. Further, pulp fibers, such as wood pulp fibers, especially commercially available wood pulp fibers would have known diameter (width) from the supplier of the wood pulp or are generally known in the industry and/or can ultimately be measured according to the Kajaani FiberLab Fiber Analyzer SubTest Method described below.

[0175] A fibrous structure comprising filaments of appropriate basis weight (approximately 5 to 20 grams/square meter) is cut into a rectangular shape sample, approximately 20 mm by 35 mm. The sample is then coated using a SEM sputter coater (EMS Inc, PA, USA) with gold so as to make the filaments relatively opaque. Typical coating thickness is between 50 and 250 nm. The sample is then mounted between two standard microscope slides and compressed together using small binder clips. The sample is imaged using a 10 objective on an Olympus BHS microscope with the microscope light-collimating lens moved as far from the objective lens as possible. Images are captured using a Nikon DI digital camera. A Glass microscope micrometer is used to calibrate the spatial distances of the images. The approximate resolution of the images is 1 m/pixel. Images will typically show a distinct bimodal distribution in the intensity histogram corresponding to the filaments and the background. Camera adjustments or different basis weights are used to achieve an acceptable bimodal distribution. Typically ten images per sample are taken and the image analysis results averaged.

[0176] The images are analyzed in a similar manner to that described by B. Pourdeyhimi, R. and R. Dent in Measuring fiber diameter distribution in nonwovens (Textile Res. J. 69 (4) 233-236, 1999). Digital images are analyzed by computer using the MATLAB (Version. 6.1) and the MATLAB Image Processing Tool Box (Version 3.) The image is first converted into a grayscale. The image is then binarized into black and white pixels using a threshold value that minimizes the intraclass variance of the thresholded black and white pixels. Once the image has been binarized, the image is skeltonized to locate the center of each fiber in the image. The distance transform of the binarized image is also computed. The scalar product of the skeltonized image and the distance map provides an image whose pixel intensity is either zero or the radius of the fiber at that location. Pixels within one radius of the junction between two overlapping fibers are not counted if the distance they represent is smaller than the radius of the junction. The remaining pixels are then used to compute a length-weighted histogram of filament diameters contained in the image.

Kajaani FiberLab Fiber Analyzer SubTest Method

Instrument Start-Up:

[0177] 1. Turn on Kajaani FiberLab Fiber Analyzer unit first, then computer and monitor. [0178] 2. Start FiberLab program on computer.

Instrument Operation:

[0179] 1. File.fwdarw.New (or click on New File icon) [0180] 2. New Fiber Analysis screen pops up. [0181] a. Sample Point: select the folder you would like data stored in (to add a new folder see Adding a New Folder [0182] b. Name: add condition or sample name/identifier here [0183] c. Date [0184] d. Time [0185] e. Sample Weight: mg of dry fiber in the 50 ml sample (can leave blank if NOT measuring for coarseness). This is the number calculated in #10 of Sample Prep below. [0186] 3. Make sure 50 ml of sample is placed in a Kajaani beaker and click Start [0187] 4. Optional: Distribution.fwdarw.Measured Values [0188] a. Fibers: the final count of measured fibers should be at least 10,000 [0189] b. Fibers/sec: this number must stay below 70 fibers/sec or the sample will automatically be diluted. If the sample is diluted during an analysis, the coarseness value will be invalid and will need to be discarded. [0190] 5. A bar indicating the measurement status of a sample appears on the computer monitor. Do not start an analysis until the indicated status is Wait State. When the analysis is completed, wait for Wait State to appear, then close the New Fiber Analysis window. You can now repeat #1- [0191] 6. When finished with all samples, close the FiberLab program before turning off the Kajaani FiberLab analyzer unit. [0192] 7. Shutdown computer.

Sample Preparation:

Target Sample Size:

[0193] Softwood: 4 mg/50 ml.fwdarw.160 mg BD in 2000 ml (170-175 mg from sheet) [0194] Hardwood: 1 mg/50 ml.fwdarw.40 mg BD in 2000 ml (40-45 mg from sheet) [0195] 1. For n=3 analysis, weigh and record weight of sample torn (avoiding cut edges) from 3 different pulp sheets of same sample using guidelines above for sample size. Place weighed samples into a suitable container for soaking of pulp. [0196] 2. Using the 3 sheets that samples were torn from, perform moisture content analysis. Note: This step can be skipped if coarseness measurement is not required. [0197] 3. Calculate the actual bone dry weight of the samples weighed in #1, by using the average moisture determined in #2. [0198] 4. Allow pulp samples to soak in water for 10-15 minutes. [0199] 5. Place 1st sample and soaking water into the Kajaani manual disintegrator. Fill disintegrator up to 250 ml mark with more water. [0200] 6. Using the hand dasher, plunge up and down until sample is separated into individual fibers. [0201] 7. Transfer sample to a 2000 ml volumetric flask. Make sure to wash off and collect any fibers that may have adhered to the dasher. [0202] 8. Dilute up to 2000 ml mark. It is important to be as precise as possible for repeatable coarseness results. [0203] 9. Take a 50 ml aliquot and place into a Kajaani beaker. Place beaker on the sampler unit. [0204] 10. Calculate the mg of BD pulp in 50 ml aliquot [0205] a. (BD mg of sample/2000 ml)50 ml [0206] 11. Begin Step #1 above in Instrument Operation

[0207] The water used in this method is City of Cincinnati Water or equivalent having the following properties: Total Hardness=155 mg/L as CaCO.sub.3; Calcium content=33.2 mg/L; Magnesium content=17.5 mg/L; Phosphate content=0.0462

Adding a New Folder to Sample Point Menu:

[0208] 1. Settings.fwdarw.Common Settings.fwdarw.Sample Folders [0209] a. Type in name of new folder.fwdarw.Add.fwdarw.OK [0210] Note: You must close the FiberLab program and re-open program to see the new folder appear in the menu.

Collecting Data in Excel File:

[0211] 1. Start FiberLab's Collect 1.12 program. [0212] 2. Open Windows Explorer (not to full screen-you must be able to see both the Explorer and the Collect windows. [0213] 3. In Windows Explorer. . . . Select folder that data was stored in [0214] 4. Highlight data to be put in Excel.fwdarw.right click on Copy.fwdarw.drag highlighted samples to the Collect window.fwdarw.Save text [0215] 5. Click Save In menu bar and select My briefcase. Open the 2007 folder, type in file name and click Save. A message will appear saying the selected samples have been saved. Click OK (the sample names will disappear from the Collect window. [0216] 6. Open Excel. Then. . . . Open.fwdarw.Look In My Briefcase.fwdarw.2007.fwdarw.at bottom, select All Files (*.*) in the Files of Type bar.fwdarw.find text file just saved and open.fwdarw.click thru the Text Import Wizard screens (next, next, finish)

Emtec Test Method

[0217] TS7 and TS750 values are measured using an EMTEC Tissue Softness Analyzer (Emtec TSA) (Emtec Electronic GmbH, Leipzig, Germany) interfaced with a computer running Emtec TSA software (version 3.19 or equivalent). According to Emtec, the TS7 value correlates with the real material softness, while the TS750 value correlates with the felt smoothness/roughness of the material. The Emtec TSA comprises a rotor with vertical blades which rotate on the test sample at a defined and calibrated rotational speed (set by manufacturer) and contact force of 100 mN. Contact between the vertical blades and the test piece creates vibrations, which create sound that is recorded by a microphone within the instrument. The recorded sound file is then analyzed by the Emtec TSA software. The sample preparation, instrument operation and testing procedures are performed according the instrument manufacture's specifications.

Sample Preparation

[0218] Test samples are prepared by cutting square or circular samples from a finished product. Test samples are cut to a length and width (or diameter if circular) of no less than about 90 mm, and no greater than about 120 mm, in any of these dimensions, to ensure the sample can be clamped into the TSA instrument properly. Test samples are selected to avoid perforations, creases or folds within the testing region. Prepare 8 substantially similar replicate samples for testing. Equilibrate all samples at TAPPI standard temperature and relative humidity conditions (23 C.2 C. and 50%+2%) for at least 1 hour prior to conducting the TSA testing, which is also conducted under TAPPI conditions.

Testing Procedure

[0219] Calibrate the instrument according to the manufacturer's instructions using the 1-point calibration method with Emtec reference standards (ref.2 samples). If these reference samples are no longer available, use the appropriate reference samples provided by the manufacturer. Calibrate the instrument according to the manufacturer's recommendation and instruction, so that the results will be comparable to those obtained when using the 1-point calibration method with Emtec reference standards (ref.2 samples).

[0220] Mount the test sample into the instrument and perform the test according to the manufacturer's instructions. When complete, the software displays values for TS7 and TS750. Record each of these values to the nearest 0.01 dB V.sup.2 rms. The test piece is then removed from the instrument and discarded. This testing is performed individually on the top surface (outer facing surface of a rolled product) of four of the replicate samples, and on the bottom surface (inner facing surface of a rolled product) of the other four replicate samples.

[0221] The four test result values for TS7 and TS750 from the top surface are averaged (using a simple numerical average); the same is done for the four test result values for TS7 and TS750 from the bottom surface. Report the individual average values of TS7 and TS750 for both the top and bottom surfaces on a particular test sample to the nearest 0.01 dB V.sup.2 rms. Additionally, average together all eight test value results for TS7 and TS750, and report the overall average values for TS7 and TS750 on a particular test sample to the nearest 0.01 dB V.sup.2 rms.

Probe Tack Moist Adhesive Energy Test for Sheet-to-Sheet Stickiness in Moist Conditions

[0222] This method, often referred to as Probe Tack, quantifies the moist adhesive energy (mg*cm/cm.sup.2) required to separate two sheets after being pressed together in a moist, foggy localized environment, under prescribed conditions detailed here. Sheets are pre-conditioned for a minimum of 2 hours and tested in a laboratory maintained at 23 C. (+/1 C.) and 50% (+/2%) relative humidity.

[0223] The equipment and materials used in performing this measure are as follows: [0224] Thwing-Albert EJA Vantage with compression/softness fixtures and MAP4 software (or equivalent). [0225] Abrasion-Resistant Natural Latex Rubber (0.020 inches thick) [0226] O-ring, 1 ID, 1 OD, round cross-section shape, elastic rubber. [0227] Key hose clamp, 1.5 inch (Powertec, part #70247, or equivalent). [0228] Brass Flat Washer, 1 Screw Size, 3 OD, 0.12-0.19 Thick [0229] Venta-sonic Ultrasonic Humidifier (model VS-205 or similar), set to Cool mist, on highest Power Spray knob setting, and highest Humidity knob setting. [0230] Super-Flexible Duct Hose for Fumes 2 ID2 3/16 OD, Blue, 5 ft. Length

[0231] The Thwing-Albert (14 W. Collings Ave., West Berlin, NJ) EJA Vantage Compression/Softness Tester (model 1750-2005 or similar) is equipped with a 2500 g load cell (force accuracy is +/0.25% when measuring value is between 10%-100% of load cell capacity, and 0.025% when measuring value is less than 10% of load cell capacity), a 1.128 inch diameter steel pressure foot (one square inch cross sectional area) which is aligned parallel to the steel anvil (2.5 inch diameter). Thwing-Albert software (MAP version 3) controls the motion and data acquisition of the instrument.

[0232] A 1.128 inch diameter circular piece of the latex rubber material is adhered to the bottom face of the compression foot using one smooth layer (not tape overlapping) of thin doubled sided tape (Scotch brand permanent cat. 665, or similar), positioning the rubber material such that it completely and smoothly covers the compression foot surface.

[0233] The load cell is then zeroed (using the software) to 0+/0.5 grams of force. The pressure foot is then slowly lowered until it makes contact with the steel anvil, achieving a force of 10+/2 grams. The pressure foot is then moved 4.5 cm up from this position (i.e., the opening distance)this new position is then set to zero (using the Map software) and is the starting position for the test. The test sheets are prepared as follows. Two usable unit sheets are required for this test, both with dimensions between 2.5-six inches in both length and width. Toilet paper usable units are typically cut and perforated in this size range, so two representative sheets from a toilet paper roll can be most often used directly. If the test sheets are larger than six inches in either dimension, cut it down to be approximately in the four inch size range. For each individual test, two such sheets are used: one is to be attached to the compression foot, and the other to be placed on top the anvil, beneath the compression foot. Prepare six test sheets, since three individual tests are to be performed and averaged to calculate a reportable result.

[0234] This test can be run with different usable unit faces touching each other during the test. Many products are created with a side that typically faces the consumer (i.e., the outside face of a rolled paper product). This test can be run with the outside face contacting another outside face, inside contacting inside, or outside face contacting inside. This sided information shall be reported with the test results. For clarity, only the outside face (against another outside face) of the sheets will be described in testing below, but the inside (against another inside face, or an outside face) would be performed in the same manner.

[0235] Using the first test sample set, center the square piece, with its outside face pointing downward, below the pressure foot, then wrap it around the pressure foot, without physically touching the portion of the sheet that will be (eventually) contacting the other sheet (that will be setting on the anvil). Use the elastic rubber o-ring or the key hose clamp to hold the square test piece onto the pressure foot, with enough tension on the sheet to keep it in smooth, close contact with the pressure foot test surface. The key hose clamp may be required if the sample slips off of the pressure foot during the test, since it can be tightened to a greater degree compared to the clastic o-ring.

[0236] Place the other piece from the first test sample set, with its outside facing upwards, on top the anvil, centered below the pressure foot. Again, do not physically touch the region of the sheet that will be in contact with the other sheet (now attached on the pressure foot). Place the brass flat washer weight on top of the sheet, with its hole (1.56 inches in diameter) centered below the pressure foot (such that the pressure foot is at least 0.1 inches away from any edge of the inner diameter of the washer). A heavier weight may be used if needed to hold sample in place during the test. As stated previously, what is described here is for an outside face contacting another outside face of sample product.

[0237] After ensuring the ultra-sonic humidifier is clean and in good working order, fill its reservoir tank with room temperature (23 C) deionized (DI) water. The DI water used must be fresh, not exposed to the environment for more than 24 hours, and the reservoir tank rinsed out and cleaned every 24 hours. Attach one end of the flexible duct hose into the humidifier opening (where the fog comes out). Turn on the humidifier, always using the cool mist setting, the highest humidity setting, and the highest power output flow level setting, and ensure that no fog leaks out at the hose connection point, and with a steady stream of fog exiting the other end of the duct hose.

[0238] With a steady stream of fog flowing from the duct hose, position the hose end about two inches from the test sample pieces, centered between the 4.5 cm gap between them, at a slight downward angle, so that the fog engulfs both the upper and lower paper samples as much as possible. After 30+/1 seconds, the Map software is then used to initiate the test and its crosshead movement of the pressure foot moving downwards. Do not move the fog hose, but rather continue to apply fog while test runs initially and compression foot moves down. The fog hose is moved away from the sample after the upper and lower sheet sections are in contact, achieving a pressure greater than 300 g/in.sup.2.

[0239] The Map software is programmed to do the following actions after the start button is pressed. First, the load cell is re-zeroed, followed by a pause of one second. The pressure foot is then moved downward at a speed of 50.8 cm/min for a distance of 3.5 cm (which is the initial gap minus 1.0 cm). Then, the pressure foot continues to move downward, but at a speed of 10 cm/min until the software realizes a force of at least 20 grams from the load cell (which means the pressure foot and upper sheet sample has made initial contact with the lower sheet sample). At this point, the speed is reduced to 1.0 cm/min until the force reaches at least 2300 grams. The pressure foot then stops its movement, and waits exactly 5 seconds, after which the pressure foot moves upward at a speed of 20 cm/min (and acceleration set to 127 mm/sec.sup.2). Force and position data are collected and recorded by the software during this upward movement (back to the home position) at a rate of 50 points per second.

[0240] After the test is completed, the software calculates the adhesive energy result from the test (units: mg*cm/cm.sup.2) as follows. As stated earlier, analysis data is only recorded during the upward movement of the pressure foot; thus, the initial forces of the data array (consisting of position and force) is near 2000 grams (when the probe position is near-4.5 cm, sheets in contact with each other), which falls rapidly as the pressure foot pulls away and the two sheets become separated. Eventually, a negative force is observed, and after the two sheets are completely separated, the force is approximately zero until the data array ends and the probe reaches its home (zero) position. First, the position readings (cm) in the array are inverted (multiplied by 1), so that pressure foot positions below the home (zero) position are positive, (i.e., decreasing in magnitude as the probe moves upward). Next, in order to obtain an accurate baseline force reading after the two sheets are completely separated from each other, the force data just before the pressure foot has returned to its home position is averaged (roughly 29 data points, typically 0.5-2.5 mm below the home position) to calculate an average baseline force. However, if the sheets are still connected within this distance range, the test is invalid, since the baseline force would be inaccurate. In this case, the opening distance (initial set at 4.5 cm) must be moved higher up (in 1 cm increments), in order to achieve complete separation of the two sheets and an accurate baseline force reading. Assuming the two sheet faces were separated in calculating average baseline force, then this baseline force value is then subtracted from all the force readings in the array.

[0241] Next, the array is reduced to only the points to be used in calculating adhesive energy. This new array starts with the first negative force point (after sheet to sheet contact) and continues until a positive force point occurs, with this new array ending with the last negative force point before such (positive) point. Thus, the new array now consists of only negative forces. These negative forces are then inverted to positive (by multiplying by 1), and the area under the curve (where x-axis is position (cm) and y-axis is force (g)) is calculated via numerical integration. The result has units of g*cm, which is then divided by the contact area, which in this case is 6.45 cm.sup.2 (1.00 in.sup.2), and then converted to mg*cm/cm.sup.2 by multiplying by 1000.

[0242] The tested samples are then removed, the probe and anvil are dried off from any residual moisture present, and the next sample set is tested in the same manner as described. For a typical sample, 3 test results are produced and averaged, reporting the probe tack moist adhesive energy result to the nearest 1 mg*cm/cm.sup.2, along with the sides facing each other during testing (for example, outside facing outside, or inside facing inside, or outside facing inside). For clarity, only the outside face (against another outside face) of the sheets was used.

Crystallinity Test Method-Differential Scanning calorimetry

[0243] The equipment and materials used for this method are: [0244] Differential Scanning calorimeter (DSC): TA Instruments Discovery 1 DSC with RCS chiller [0245] DSC Firmware: 5.7.0.14 [0246] Control/analysis software: Trios, Version 5.0.0.44608 [0247] Pan: TA Instruments Tzero aluminum Pan Catalog #: T 141020 [0248] Lid: TA Instruments Tzero Hermetic Lid Catalog #: T 240408 [0249] Biopsy punch: Integra Miltex 4 mm disposable biopsy punch [0250] Balance: Mettler Toledo AB135-S/FACT Calibrated biyearly

[0251] Samples were stored in plastic bags at room temperature. For each sample repetition, a new Tzero pan and lid were tared and weight recorded. Using a 4 mm biopsy punch, a circle of web was punched out and placed in the pan. Sample size was between 15-18 mg. The sample weight was measured and recorded using a MT balance accurate to 0.01 mg (calibrated bi-yearly). The pan/lid was sealed using a TA Instrument pan crimper with corresponding Tzero crimping tools. Samples were run in triplicate. The pans were loaded into the DSC autosampler and ran in sequence using an empty Tzero pan/lid as reference. The DSC oven was purged with 50 ml/min nitrogen gas. The loading oven temperature was set to 25 C. The experiment temperature profile was as follows: [0252] Initial temp: 25 C. [0253] Heat Ramp at 5 C./min from 25 C. to 230 C.

[0254] Percent crystallinity was calculated from the integral of the melting peak (J/g) divided by the heat of fusion of fully crystallized PVOH (161.4 J/g) The average of the three repetitions is reported.

Cold Water Solubility Test Method

[0255] Fill a 2 L beaker with 1000 g of 25 C. deionized water and add 1.0 g of a melt blown PVOH web. Stir for 2 hours using a magnetic stir bar. After 2 hours, but while the mixture is still stirring, transfer four drops of the PVOH and water mixture to a microscope slide. This will ensure that no small, undissolved PVOH will settle to the bottom of the beaker. Place the slide on the stage of an optical microscope (VHX-5000 Keyence digital microscope). Using the 200 objective lens, focus the image to any debris in solution. Scan across the four drop sample of aqueous PVOH mixture using the XY stage and optically inspect for any residual fiber microstructure. Residual fiber microstructure includes individual fibers and/or fiber pieces that are not dissolved and/or partially dissolved fiber or fiber pieces that are swollen with water. If no residual fiber microstructure is optically detected the sample is considered cold water soluble.

Biodegradation Test Method

[0256] The biodegradability of the PVOH filaments was determined following the OECD 301B Ready Biodegradability CO2 Evolution Test Guideline. In this study, the test substance is the sole carbon and energy source and under aerobic conditions microorganisms metabolize the test substance producing CO2 or incorporating the carbon into biomass. The amount of CO2 produced by the test substance (corrected for the CO2 evolved by the blank inoculum) is expressed as a percentage of the theoretical amount of CO2 (ThCO2) that could have been produced if the organic carbon in the test substance was completely converted to CO2. Test substances achieving 60% of TCO.sub.2 within 10 days of reaching 10% TCO.sub.2 are regarded as readily biodegradable.

Surface Smoothness

[0257] Surface Smoothness is measured by first generating a digital image of the fabric contacting surface of a sample using an FRT MicroSpy Profile profilometer (FRT of America, LLC, San Jose, Calif.) and then analyzing the image using Nanovea Ultra software version 6.2 (Nanovea Inc., Irvine, Calif.). Samples (either base sheet or finished product) are cut into squares measuring 145145 mm. The samples are then secured to the x-y stage of the profilometer using tape, with the fabric contacting surface of the sample facing upwards, being sure that the samples were laid flat on the stage and not distorted within the profilometer field of view.

[0258] Once the sample is secured to the stage the profilometer is used to generate a three-dimensional height map of the sample surface. A 16021602 array of height values is obtained with a 30 m spacing resulting in a 48 mm MD48 mm CD field of view having a vertical resolution 100 nm and a lateral resolution 6 m. The resulting height map is exported to .sdf (surface data file) format.

[0259] Individual sample .sdf files are analyzed using Nanovea Ultra version 6.2 by performing the following functions: [0260] (1) Using the Thresholding function of the Nanovea Ultra software the raw image (also referred to as the field) is subjected to thresholding by setting the material ratio values at 0.5 to 99.5 percent such that thresholding truncates the measured heights to between the 0.5 percentile height and the 99.5 percentile height; [0261] (2) Using the Fill In Non-Measured Points function of the Nanovea Ultra software the non-measured points are filled by a smooth shape calculated from neighboring points; [0262] (3) Using Filtering>Wavyness+Roughness function of the Nanovea Ultra software the field is spatially low pass filtered (waviness) by applying a Robust Gaussian Filter with a cutoff wavelength of 0.095 mm and selecting manage end effects; [0263] (4) Using the Filtering-Wavyness+Roughness function of the Nanovea Ultra software the field is spatially high pass filtered (roughness) using a Robust Gaussian Filter with a cutoff wavelength of 0.5 mm and selecting manage end effects; [0264] (5) Using the Parameter Tables study function of the Nanovea Ultra software ISO 25178 Values Sq (root mean square height, expressed in units of mm) and Sa (arithmetic mean height, expressed in units of mm) are calculated and reported; [0265] (6) Using the Abbott-Firestone Curve study function of the Nanovea Ultra software an Abbott-Firestone Curve is generated from which interactive mode is selected and a histogram of the measured heights is generated, from the histogram an S90 value (95 percentile height (c2) minus the 5 percentile height (c1), expressed in units of mm) is calculated.

[0266] Based upon the foregoing, three values, indicative of surface smoothness are reportedSq, Sa and S90, which all have units of mm. The units have been converted to microns for use herein.

Tensile

[0267] Samples for tensile strength testing are prepared by cutting a 3 (76.2 mm)5 (127 mm) long strip in either the machine direction (MD) or cross-machine direction (CD) orientation using a JDC Precision Sample Cutter (Thwing-Albert Instrument Company, Philadelphia, Pa., Model No. JDC 3-10, Ser. No. 37333). The instrument used for measuring tensile strengths is an MTS Systems Sintech 11S, Serial No. 6233. The data acquisition software is MTS TestWorks for Windows Ver. 4 (MTS Systems Corp., Research Triangle Park, N.C.). The load cell is selected from either a 50 or 100 Newton maximum, depending on the strength of the sample being tested, such that the majority of peak load values fall between 10 and 90 percent of the load cell's full scale value. The gauge length between jaws is 20.04 inches (50.81 mm). The jaws are operated using pneumatic-action and are rubber coated. The minimum grip face width is 3 (76.2 mm), and the approximate height of a jaw is 0.5 inches (12.7 mm). The crosshead speed is 100.4 inches/min (2541 mm/min), and the break sensitivity is set at 65 percent. The sample is placed in the jaws of the instrument, centered both vertically and horizontally. The test is then started and ends when the specimen breaks. The peak load is recorded as either the MD tensile strength or the CD tensile strength of the specimen depending on the sample being tested. At least six (6) representative specimens are tested for each product, taken as is, and the arithmetic average of all individual specimen tests is either the MD or CD tensile strength for the product.

Roll Firmness

[0268] Roll Firmness is measured using the Kershaw Test as described in detail in U.S. Pat. No. 6,077,590, which is incorporated herein by reference in a manner consistent with the present disclosure. The apparatus is available from Kershaw Instrumentation, Inc. (Swedesboro, N.J.) and is known as a Model RDT-2002 Roll Density Tester.

EXAMPLES

Non-Limiting Examples of Cold Water Soluble Blended PVOH Melt Compositions and Filaments

TABLE-US-00001 TABLE 1 Readily Biodegradable as measured by > 60% TCO.sub.2 within Cold 10 days of Inventive Melt Melt water reaching 10% SAMPLE Example Processable Miscibility soluble TCO.sub.2 Emtec, TS7 A Yes Yes Yes Yes Yes 7.0 B Yes Yes Yes Yes Yes 7.3 C Yes Yes Yes Yes Yes 7.2 D No Yes Yes No No 7.1 E No Yes Yes Yes Yes 8.9 F No Yes No No No Could not spin filaments due to poor miscibility G No No No No No Could not spin filaments due to poor melt processability H No Yes Yes No No 7.5 I No Yes Yes No No 7.1 J No Yes Yes Yes Yes 8.0

Example 1Inventive Sample A of a PVOH Blend that is Cold-Water Soluble and Low Wet Tack

[0269] In a 40:1 APV Baker twin-screw extruder (Baker Perkins Co., Grand Rapids, MI) with eight temperature zones, 131 g/min of Poval 4-98 and 131 g/min of Poval 5-88 were mixed, using the temperature profile shown in Table 2 below, with 53 g/min water in Zone 1 at a 50:50 weight ratio. This mixture was then conveyed down the barrel through zones 2 through 8 at a screw speed of 500 RPM, where a second water injection of 97 g/min was introduced at zone 6. After exiting the extruder, the material was a homogeneous, uniform melt-processed PVOH blended composition a moisture content of 40%. The moisture content was determined by collecting a melt sample in a plastic syringe and then ejecting the melt sample from the syringe onto an aluminum weight dish. The dish was weighed before and after drying the in an oven overnight at 110 C. to determine how much water was in the original sample. The extruder barrel temperature setpoints for each zone are shown below in TABLE 2.

TABLE-US-00002 TABLE 2 Zone 1 2 3 4 5 6 7 8 Temperature 60 120 178 200 200 200 250 250 ( F.)

[0270] The temperature of the melt exiting the 40:1 extruder is between 25 and 270 F. The melt temperature was measured with an in-line thermocouple. From the extruder, the melt was fed to a Zenith gear pump, Model #60-20000-2366-4 (Zenith Precision Metering Monroe, NC), two static mixers where additional 179 g/min of water was added. The melt composition at this point in the process was 58% water and 42% PVOH where the solids PVOH was composed of 50% Poval 4-98 and 50% Poval 5-88. From the static mixers, the PVOH melt composition was delivered pumped to a melt blowing spinneret via a melt pump (Zenith gear pump, Model #60-20000-2366-4)

[0271] A plurality of PVOH blended filaments was attenuated with a steam saturated air stream at 74 C. and 88% relative humidity to form a layer of filaments between 1 and 2 gsm that is collected either directly onto a forming belt or onto a differential density wet laid cellulose structure that contains 48% continuous high density knuckle area.

[0272] As shown in TABLE 1 and FIG. 13 the resulting product had a TS7 value of 7.0 as measured by the Emtec Test Method and a Finished Product Wet Tack Area less than 9500 g/cm, as described in the Probe Tack Method. The resulting blended PVOH layer of filaments was cold-water soluble as the two PVOH grades were intimately mixed which enabled the medium hydrolysis PVOH to disrupt the hydrogen bonding capability of the high hydrolysis PVOH thereby reducing the % crystallinity of the blended fiber.

[0273] The relative composition of the medium hydrolysis PVOH (Poval 5-88) and high hydrolysis PVOH (Poval 4-98) in the filament can be varied from 35% 5-88/65% 4-98 to 75% 5-88/25% 4-98 by varying the relative flowrates of the two PVOH resins into the twin screw extruder. PVOH blended filaments of these compositions possess cold water solubility and low wet tack.

Example-2Inventive Sample B of a PVOH Blend that is Cold-Water Soluble and Low Wet Tack

[0274] In a 40:1 APV Baker twin-screw extruder (Baker Perkins Co., Grand Rapids, MI)_with eight temperature zones, 131 g/min Poval 3-80 and 131 g/min Poval 4-98 were mixed, using the temperature profile shown in Table 2, with 53 g/min water in Zone 1 at a 50:50 weight ratio. This mixture was then conveyed down the barrel through zones 2 through 8 like EXAMPLE 1. From the extruder, the melt was fed to a Zenith gear pump (Model #60-20000-2366-4) and passed through two static mixers where another 179 g/min of water was added. The melt composition at this point in the process was 58% moisture and 42% PVOH where the solids PVOH is composed of 50% Poval 3-80 and Poval 4-98. The aqueous blended PVOH melt composition is homogeneous and uniform. The moisture content was determined by collecting a melt sample in a plastic syringe and then ejecting the melt sample from the syringe onto an aluminum weight dish. The dish was weighed before and after drying the in an oven overnight at 110 C. to determine how much water was in the original sample. From the static mixers, the PVOH melt composition was delivered to a melt blowing spinneret via a Zenith gear melt pump (Model #60-20000-2366-4).

[0275] A plurality of PVOH blended filaments was attenuated with a steam saturated air stream at 74 C. and 88% relative humidity to form a layer of filaments between 1 and 2 gsm that was collected either directly onto a forming belt or onto a wet laid cellulose structure. A blended PVOH melt composition of Poval 3-80 and Poval 4-98 was spun into a blended filament layer onto cellulose and exhibits the inventive properties of cold water solubility, TS7, and wet tack.

[0276] As shown in TABLE 1 and FIG. the resulting product had a TS7 value of 7.3 as measured by the Emtec Test Method, and had a Finished Product Wet Tack Area less than 9500 g/cm. The resulting blended PVOH layer of filaments was cold-water soluble because the two PVOH grades were intimately mixed which enabled the medium hydrolysis PVOH to disrupt the hydrogen bonding capability of the high hydrolysis PVOH thereby reducing the % crystallinity of the blended fiber.

[0277] The relative composition of the medium hydrolysis PVOH (Poval 3-80) and high hydrolysis PVOH (Poval 4-98) in the filament can be varied from 35% 3-80/65% 4-98 to 75% 3-80/25% 4-98 by varying the relative flowrates of the two PVOH resins into the twin screw extruder. PVOH blended filaments of these compositions possess cold water solubility and low wet tack.

Example-3Inventive Sample C of a PVOH Blend that is Cold-Water Soluble and Low Wet Tack

[0278] For this example, the same equipment was used as described in EXAMPLE 1. In a 40:1 APV Baker twin-screw extruder with eight temperature zones, 131 g/min Poval 5-88 and 131 g/min Poval 27-96 were mixed with 53 g/min water in Zone 1 at a 50:50 weight ratio. This mixture was then conveyed down the barrel through zones 2 through 8 where another 97 g/min water was added like Example 1. From the extruder, the melt was fed to a Zenith gear pump, and then delivered to a series of static mixers where additional water was added. The melt composition at this point in the process was 80% moisture and 20% PVOH where the solids PVOH is composed of 50% Poval 5-88 and 50% Poval 27-96. From the static mixers, the PVOH melt composition was delivered to a melt blowing spinneret via a melt pump.

[0279] A plurality of PVOH blended filaments was attenuated with a saturated air stream to form a layer of filaments between 1 and 2 gsm that was collected either directly onto a forming belt or onto a wet laid cellulose structure.

[0280] As shown in TABLE 1 and FIG. 13 the resulting product had a TS7 value of 7.2 as measured by the Emtec Test Method, and had a Finished Product Wet Tack Area less than 9500 g/cm. The resulting blended PVOH layer of filaments was cold-water soluble as the two PVOH grades were intimately mixed which enabled the medium hydrolysis PVOH to disrupt the hydrogen bonding capability of the high hydrolysis PVOH thereby reducing the % crystallinity of the blended fiber.

[0281] The relative composition of the medium hydrolysis PVOH (Poval 5-88) and high hydrolysis PVOH (Poval 27-96) in the filament can be varied from 35% 5-88/65% 27-96 to 75% 5-88/25% 27-96 by varying the relative flowrates of the two PVOH resins into the twin screw extruder. PVOH blended filaments of these compositions will possess cold water solubility and low wet tack.

Example-4Comparative Sample D of a PVOH Blend that is not Cold-Water Soluble

[0282] For this example, the same equipment was used as described in Example 1. In a 40:1 APV Baker twin-screw extruder with eight temperature zones, 75 g/min of Poval 4-98 and 75 g/min of Poval 27-96 were mixed with 100 g/min of water in Zone 1 at a 50:50 weight ratio. This mixture was then conveyed down the barrel through zones 2 through 8 at a screw speed of 500 RPM, where a 100 g/min of water was introduced at zone 6. After exiting the extruder, the material was a melt-processed PVOH blended composition with a moisture content of 60%. The extruder barrel temperature setpoints for each zone are shown below in TABLE 3.

TABLE-US-00003 TABLE 3 Zone 1 2 3 4 5 6 7 8 Temperature 60 120 178 200 200 200 250 250 ( F.)

[0283] The temperature of the melt exiting the 40:1 extruder was between 25 and 270 F. From the extruder, the melt was fed to a Zenith gear pump, and then delivered to a series of static mixers where 230 g/min of water was added. The melt composition at this point in the process was 80% moisture and 20% PVOH where the solids PVOH was composed of 50% Poval 4-98 and 50% Poval 27-96. From the static mixers, the PVOH melt composition was delivered to a melt blowing spinneret via a melt pump.

[0284] A plurality of PVOH blended filaments was attenuated with a saturated air stream to form a layer of filaments between 1 and 2 gsm that was collected either directly onto a forming belt or onto a wet laid cellulose structure.

[0285] As shown in TABLE 1 and FIG. 13 the resulting product had a TS7 value of 7.1 as measured by the Emtec Test Method and a Finished Product Wet Tack Area less than 9500 g/cm. The resulting blended PVOH layer of filaments was not cold-water soluble as the two PVOH components both had a degree of hydrolysis greater than 92%.

Example-5 Comparative Sample E of a PVOH Blend that has High TS7 and High Wet Tack

[0286] For this example, the same equipment was used as described in Example 1. In a 40:1 APV Baker twin-screw extruder with eight temperature zones, 75 g/min of Poval 5-88 and 75 g/min of Poval 30-92 were mixed with 100 g/min of water in Zone 1 at a 50:50 weight ratio. This mixture was then conveyed down the barrel through zones 2 through 8 like EXAMPLE 4 where another 100 g/min of water is added to the melt. From the extruder, the melt was fed to a Zenith gear pump, and then delivered to a series of static mixers where 230 g/min of water was added. The melt composition at this point in the process was 80% moisture and 20% PVOH where the solids PVOH was composed of 50% Poval 5-88 and Poval 30-92. From the static mixers, the PVOH melt composition was delivered to a melt blowing spinneret via a melt pump.

[0287] A plurality of PVOH blended filaments was attenuated with a saturated air stream to form a layer of filaments between 1 and 2 gsm that was collected either directly onto a forming belt or onto a wet laid cellulose structure.

[0288] As shown in TABLE 1 and FIG. 13 the resulting product had a TS7 value of 8.9 as measured by the Emtec Test Method, and had a Finished Product Wet Tack Area greater than 9500 g/cm. The resulting blended PVOH layer of filaments was cold-water soluble. This product does not possess the desired surface softness as measured by its high TS7 value and may be considered rough when wiping.

Example-6 Comparative Sample F of a PVOH Blend that is not Melt Miscible Due to Disparate Hydrolysis Levels

[0289] For this example, the same equipment was used as described in Example 1. In a 40:1 APV Baker twin-screw extruder with eight temperature zones, 131 g/min Poval 4-98 and 131 g/min Poval 5-78 were mixed with 53 g/min water in Zone 1 at a 50:50 weight ratio. This mixture was then conveyed down the barrel through zones 2 through 8 like where another 97 g/min of water was mixed into the melt EXAMPLE 4. From the extruder, the melt was fed to a Zenith gear pump, and then delivered to a series of static mixers where 197 g/min of water was added. The melt composition at this point in the process was 60% moisture and 40% PVOH where the solids PVOH was composed of 50% Poval 4-98 and Poval 5-74.

[0290] As shown in TABLE 1 and FIG. 13 the melt composition was cloudy and phase separated due to the poor miscibility and mixing of the two PVOH grades due to the large difference in the degrees of hydrolysis. The poor mixing results in fiber breakage/non uniform attenuation during the melt blowing process and consequently a spun fiber layer of PVOH cannot be formed.

Example-7 Comparative SAMPLE G of a PVOH Blend that is not Melt Processable

[0291] For this example, the same equipment was used as described in Example 1. In a 40:1 APV Baker twin-screw extruder with eight temperature zones, 131 g/min Poval 5-88 and 131 g/min Elvanol 71-30 were mixed with 53 g/min of water in Zone 1 at a 50:50 weight ratio. Poval 5-88 is an 88% hydrolyzed PVOH and Elvanol 71-30 is >99% hydrolyzed PVOH. This mixture was then conveyed down the barrel through zones 2 through 8 like EXAMPLE 4 where another 97 g/min of water was added to the melt. From the extruder, the melt was fed to a Zenith gear pump, and then delivered to a series of static mixers where 179 g/min of water was added. The melt composition at this point in the process was 60% moisture and 40% PVOH where the solids PVOH was composed of 50% Poval 4-98 and Poval 5-88.

[0292] As shown in TABLE 1 and FIG. 13 the melt composition was clumpy with residual Elvanol 71-30 granules. The highly crystalline structure of the super hydrolyzed (>99%) Elvanol 71-30 prevented dissolution of the granules into water under the extrusion conditions shown in EXAMPLE 4. The incomplete dissolution of the PVOH granules results in fiber breakage/non uniform attenuation during the melt blowing process and consequently a layer of PVOH filaments was not formed.

Example-8-Comparative Sample H of a PVOH Blend that is Low in Medium Hydrolysis PVOH Content

[0293] For this example, the same equipment was used as described in Example 1. In a 40:1 APV Baker twin-screw extruder with eight temperature zones, 92 g/min of Poval 5-88 and 170 g/min of Poval 4-98 were mixed with 53 g/min water in Zone 1 at a 35:65 weight ratio. This mixture was then conveyed down the barrel through zones 2 through 8 like EXAMPLE 1 where another 97 g/min of water was added to the melt. From the extruder, the melt was fed to a Zenith gear pump, and then delivered to a series of static mixers where 179 g/min of water was added. The melt composition at this point in the process was 58% moisture and 42% PVOH where the solids PVOH was composed of 35% Poval 5-88 and 65% Poval 4-98. From the static mixers, the PVOH melt composition was delivered to a melt blowing spinneret via a melt pump.

[0294] A plurality of PVOH blended filaments was attenuated with a saturated air stream to form a layer of filaments between 1 and 2 gsm that was collected either directly onto a forming belt or onto a wet laid cellulose structure.

[0295] As shown in TABLE 1 and FIG. 13 the resulting blended PVOH layer of filaments was not cold-water soluble as the concentration of the medium hydrolysis PVOH was not sufficient to disrupt the hydrogen bonding between hydroxyl groups of the high hydrolysis PVOH.

Example 9-Comparative Sample I of a Pure, High Hydrolysis PVOH Grade

[0296] For this example, the same equipment was used as described in Example 1. In a 40:1 APV Baker twin-screw extruder with eight temperature zones, 262 g/min of Poval 4-98 was mixed with 53 g/min water in Zone 1 with no second PVOH. This composition was then conveyed down the barrel through zones 2 through 8 like EXAMPLE 1 where another 97 g/min was added to the melt. From the extruder, the melt was fed to a Zenith gear pump, and then delivered to a series of static mixers where 179 g/min of water was added. The melt composition at this point in the process was 53% moisture and 47% PVOH where the solids PVOH was 100% Poval 4-98. From the static mixers, the PVOH melt composition was delivered to a melt blowing spinneret via a melt pump.

[0297] A plurality of PVOH blended filaments was attenuated with a saturated air stream to form a layer of filaments between 1 and 2 gsm that was collected either directly onto a forming belt or onto a wet laid cellulose structure.

[0298] As shown in TABEL 2 and FIG. 13 the resulting blended PVOH layer of filaments was not cold-water soluble because due to the high concentration of hydrogen bonds and crystallinity formed between the hydroxyl groups.

Example-10 Comparative Sample J of a Pure, Medium Hydrolysis PVOH Grade

[0299] For this example, the same equipment was used as described in EXAMPLE 1. In a 40:1 APV Baker twin-screw extruder with eight temperature zones, 262 g/min of Poval 5-88 was mixed with 53 g/min of water in Zone 1 with no second PVOH. This composition was then conveyed down the barrel through zones 2 through 8 like EXAMPLE 1 where another 97 g/min of water was added to the melt. From the extruder, the melt was fed to a Zenith gear pump, and then delivered to a series of static mixers where 179 g/min of water was added. The melt composition at this point in the process was 58% moisture and 42% PVOH where the solids PVOH was 100% Poval 5-88. From the static mixers, the PVOH melt composition was delivered to a melt blowing spinneret via a melt pump.

[0300] A plurality of PVOH blended filaments was attenuated with a saturated air stream to form a layer of filaments between 1 and 2 gsm that was collected either directly onto a forming belt or onto a wet laid cellulose structure.

[0301] As shown in TABLE 1 and FIG. 13 the resulting product had a TS7 value of 8.0 as measured by the Emtec Method, and had a Finished Product Wet Tack Area greater than 9500 g/cm. The resulting blended PVOH layer of filaments was cold-water soluble. This product does not possess the desired surface softness as measured by its high TS7 value and may be considered rough during consumer use.

[0302] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as 40 mm is intended to mean about 40 mm.

[0303] Every document cited herein, including any cross referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0304] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.