NONWOVEN RECYCLABLE FABRIC AND ASSOCIATED METHODS

Abstract

A nonwoven recyclable fabric and associated methods are provided. The fabric is formed from 100% polyester, and may also include surface coatings such as hydrophilic coatings to promote heat transfer as well moisture vapor transmission rates and/or a silicone coating to promote fabric smoothness and reduce abrasiveness of the fabric. The polyester fibers forming the fabric are obtained from a mixture of monocomponent high melt polyester fibers and bicomponent high/low melt polyester fibers. The bicomponent fibers have a high melt polyester core, and a low melt polyester outer sheath. The fibers are hydroentangled with one another. After entanglement, the low melt outer sheaths are melted to form a low melt binder interspersed with the high melt polyester fibers and the remaining high melt polyester cores. The binder fuses to these fibers to provide desirable strength characteristics.

Claims

1. A nonwoven, recyclable fabric for use as a linen, the fabric comprising: a plurality of high melt polyester fibers hydroentangled with one another; and a low melt polyester binder interspersed with the plurality of high melt polyester fibers binding said plurality high melt polyester fibers to one another, the low melt polyester binder obtained by melting outer sheaths of a plurality of bicomponent polyester fibers, wherein each one of the plurality of bicomponent polyester fibers has a high melt polyester core and a low melt polyester outer sheath, said high melt polyester cores forming part of said plurality of high melt polyester fibers.

2. The fabric of claim 1, wherein the plurality of high melt polyester fibers and the high melt polyester core of each one of the plurality of bicomponent polyester fibers have a melting point of at least about 270 C.

3. The fabric of claim 3, wherein the low melt polyester outer sheath of each one of the plurality of bicomponent fibers has a melting point not greater than about 150 C.

5. The fabric of claim 1, wherein the fabric has a density of greater than 0.15 gr/cm.sup.3.

6. The fabric of claim 1, wherein the fabric is free of a chemical binder that is not polyester.

7. The fabric of claim 1, wherein the fabric includes a hydrophilic coating.

8. The fabric of claim 7, wherein the hydrophilic coating is silicone.

9. A nonwoven recyclable product, the product comprising the fabric of claim 1.

10. The product of claim 9, wherein the product is one of a bed sheet and a pillow case.

11. The product of claim 10, wherein the product includes a color changing indicator, said color changing indicator exhibiting a color change after skin contact.

12. The product of claim 10, wherein the product is a bed sheet and includes an embossed region adjacent an edge of said bed sheet.

13. A method for forming a nonwoven recyclable fabric, the method comprising the steps of: procuring a plurality of used nonwoven fabric products, wherein each of the plurality of nonwoven fabric products is formed of one hundred percent polyester fibers; melting the plurality of used nonwoven fabric products to form a polyester liquid; extruding the polyester liquid to form a bulk mass of monocomponent fibers; adding bicomponent fibers to the bulk mass of monocomponent fibers to form a fiber mixture; carding said fiber mixture to form a fiber web; hydroentagling said fiber web to form a hydroentangled web; drying said hydroentangled web in a drying oven; and compacting said hydroentangled web to a predetermined thickness.

14. The method of claim 13, further comprising winding said hydroentangled web onto a roll after the step of compacting.

15. The method of claim 13, wherein the step of drying includes melting said outer sheaths of said bicomponent fibers in a drying oven to form a polyester binder interspersed throughout the hydroentangled web.

16. The method of claim 13, wherein the step of compacting includes melting said outer sheaths of said bicomponent fibers in a compaction roller arrangement to form a polyester binder interspersed throughout the hydroentangled web.

17. The method of claim 13, wherein the step of adding said bicomponent fibers includes adding said bicomponent fibers such that the fiber mixture comprises about 5% to about 10% by weight bicomponent fibers.

18. The method of claim 17, wherein the step of adding the said bicomponent fibers includes adding said bicomponent fibers such that the fiber mixture comprises about 7% by weight bicomponent fibers.

19. The method of claim 13, further comprising applying a hydrophilic coating at one of prior to or after the step of hydroentangling.

20. The method of claim 19, wherein applying the hydrophilic coating includes applying a silicone coating.

21. The method of claim 20, wherein applying the silicone coating includes applying said silicone coating such that it amounts to not greater than 10% by weight of said fabric.

22. The method of claim 13, wherein the step of drying includes drying the hydroentangled web to less than about 7% moisture.

23. The method of claim 22, wherein the step of drying includes drying the hydroentangled web to not greater than about 2% moisture.

24. The method of claim 13, wherein the step of extruding is performed with the polyester liquid at a temperature above about 275 C.

25. The method of claim 24, wherein the step of extruding is performed with the polyester liquid at a temperature of about 290 C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

[0031] FIG. 1 is a schematic representation of an exemplary embodiment of a process for forming a fabric according to the teachings herein;

[0032] FIG. 2 is a schematic representation of an exemplary embodiment of a fiber preparation and web formation of the process of FIG. 1;

[0033] FIG. 3 is a cross sectional view of a bicomponent fiber used to form the fabric according to the teachings herein;

[0034] FIG. 4 is a partial view of a fabric produced from the process of FIG. 1, illustrating the fibers of said fabric and a binder associated with said fibers; and

[0035] FIG. 5 is an exemplary embodiment of a product produced from the fabric shown in FIG. 3.

[0036] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

[0037] Turning now to the drawings, a recyclable nonwoven fabric, products formed from this fabric, and a method of producing the fabric are described herein. The embodiments described advantageously overcome existing problems in the art by providing a nonwoven recyclable product which is readily recyclable while at the same time achieving desirable softness and coolness characteristics heretofore unachieved by prior nonwoven designs. While the following will describe an application of the fabric in a product such as a sheet or pillow case, it will be readily recognized that the fabric may be utilized in any product where a recyclable fabric is desired.

[0038] As will be described in greater detail below, the fabric is formed using only polyester fibers. Advantageously, using this single material type allows for a highly efficient recycling process which purifies, sterilizes, and rextrudes the fibers into a form which may be reused in a nonwoven, textile, or other process.

[0039] In particular, the fabric is formed from a blend of high melt monocomponent polyester fibers and bicomponent polyester fibers. The monocomponent fibers are obtained by melting down used fabric according to the teachings herein and extruding the same back into monocomponent fibers. The bicomponent fibers are added to the extruded monocomponent fibers as described below. It will be noted from the following that the bicomponent fibers may be virgin or recycled fibers. The term virgin as used herein in the context of fibers means that the fibers are newly manufactured fibers, in contrast to the monocomponent fibers mentioned above which are recovered from existing fabric via a recycling process.

[0040] The term monocomponent as used herein in the context of fibers means fibers which are formed of a single species of material and are homogeneous in their material properties. Conversely, the term bicomponent as used herein in the context of fibers means fibers which are formed with two polyester polymers having different melting points. Indeed, the bicomponent fibers are polyester fibers which have a high melt core and an outer low melt sheath. The core of the bicomponent fiber is made with polyester polymer with a melting point of about 270 C. The outer sheath of the bicomponent fiber is made with polyester polymer that has had its melting point reduced to the range of 130-150 C. by the addition of isophthalic acid.

[0041] As such, the bicomponent fibers are formed from one species of polyester which serves as the core material, and another species of polyester which serves as the outer sheath. The phrase high melt used herein in the context of fibers means fibers which have a higher melting point in comparison to a low melt fiber. As a non-limiting example, a high melt fiber may exhibit a minimum melting point of about 270 C. Ideally, the melting point is at least high enough to sterilize the melted polyester.

[0042] The phrase low melt used herein in the context of fibers means a fiber with a melting point which is lower in comparison to a high melt fiber. As a non-limiting example, a low melt fiber may exhibit a melting point of not greater than about 130 C.-150 C. The approximate terms about used relative to melting temperature is used to allow for ordinary deviations in a specified melting point of a polyester material known in the art. Put differently, high melt fibers have a first melting point, while low melt fibers have a second melting point, the second melting point being less than the first melting point.

[0043] With particular reference to FIG. 1, the same illustrates schematically a portion of a process 20 of forming a nonwoven recyclable fabric 14 according to the teachings herein. In particular, FIG. 1 depicts a spunlacing process which includes a carding of a fibers, hydroentangling the fibers, surface treatments, and drying of the fibers. Process 20 includes a fiber preparation stage 22. At this stage, fibers provided by the invention herein are blended and carded. Blending is done to achieve a desired blend of monocomponent fibers and bicomponent fibers. During this stage, monocomponent polyester fibers obtained via the process described below relative to FIG. 2 are blended with bicomponent polyester fibers. The bicomponent polyester fibers may be virgin or recycled.

[0044] Carding may be achieved using a contemporary carding arrangement. For non-limiting example, carding may be achieved via a drum carder, cottage carder, or similar devices operable to disentangle and orient the fiber mixture such that the fibers thereof are generally parallel to one another.

[0045] Once blended and carded, a fiber web 10 is produced. Fiber web 10 generally possesses a number of monocomponent and bicomponent polyester fibers arranged parallel to one another. Fiber web 10 enters a hydroentangling arrangement 24 where the fibers thereof are hydroentangled with one another using one or more hydroentangling jets 26 and hydroentangling cylinders 28.

[0046] The result is a hydroentangled web 12. This hydroentangled web 12 may then receive a topical treatment such as a hydrophilic coating applied via an application head 34. Thereafter, hydroentangled web 12 is dried in a drying oven 38. The dried hydroentangled web 12 is then fed through a roller arrangement 42 which, inter alia, compacts hydroentangled web 12 to a predetermined thickness and density to complete the formation of the fabric 14 described herein. Thereafter, post-processing steps may occur. For example, fabric 14 may be wound onto a roll 44 for later formation into a product, e.g. a product. With the foregoing general process layout in hand, the following described each step and its associated structure in greater detail.

[0047] Turning now to FIG. 2, the same illustrates another stage of the process herein. Indeed, FIG. 2 shows in schematic detail a recycling process for recycling fabric 14. In particular FIG. 2 includes a material collection step 50, in which used fabric 14 is collected. The collected used fabric 14 may be delivered to a facility having the necessary equipment for the densification, melting, and rextrusion of fibers.

[0048] As a non-limiting example, the used products may be a plurality of used products, e.g. sheets, pillow cases, etc., formed from fabric 14 and recovered from a high occupancy facility such as a hotel which are gathered or bundled in bulk. These gathered products may initially be scanned to ensure there is no foreign material, e.g. jewelry, litter, fabrics which differ from fabric 14, etc., incorporated therein. This scanning may be done via any contemporary manner, e.g. visual metal detection, x-ray, magnetic or mechanical separation, etc. Thereafter, the used fabric 14 is densified into a pellet like substance during material collection step 50.

[0049] Once it is ensured that the gathered products are free of foreign material and the gathered fabric 14 has been densified, the gathered products are then melted at step 52 to form a liquid polyester. As stated above, one hundred percent of the fibers in fabric 14 are polyester, i.e. no other fibers of different materials are present. Further, fabric 14 is predominantly formed of high melt polyester, and thus exhibits a melting point property in the range of a high melt polyester. As a result, the melting process is a high melt process requiring a sufficient temperature to melt used fabric 14 into a liquid state.

[0050] This melting step 52 contemplates the use of any known controlled melting means, including but not limited to temperature controlled crucibles, tanks, vats, etc. After melting, the liquid polyester is then extruded at an extrusion step 54. This extrusion may be accomplished via any contemporary fiber extrusion process, including but not limited to melt spinning. This extrusion process is a high temperature process (i.e. a temperature above about 275 C.), and thus provides additional sterilization beyond that provided by the initial melting step 52. It should be noted that the resultant product at this stage is a bulk mass of high melt monocomponent polyester fibers. These monocomponent polyester fibers are then ready for processing at fiber preparation stage 22 discussed above relative to FIG. 1.

[0051] As stated above, the bicomponent polyester fibers may be virgin or recycled. In the case of recycled bicomponent polyester fibers, a similar process to what is shown in FIG. 2 is conducted. Indeed, to form the bicomponent fiber, used fabric 14 is collected, densified, and melted, i.e. steps 50 and 52 are conducted. However, prior to extrusion or during extrusion isothalic acid is introduced. This isothalic acid forms the above introduced bicomponent fibers by producing fibers having a low melt outer sheath with a high melt core. The result is a bulk mass of bicomponent fibers.

[0052] Thereafter, low melt bicomponent polyester fibers are introduced to the bulk mass of monocomponent polyester fibers at step 22. It is envisioned that this addition will be done as a continuous process where a known quantity of virgin bicomponent polyester fibers are added. The result is a fiber mixture. This fiber mixture may for example comprise about 3%-10% bicomponent polyester fibers, with the balance being the extruded monocomponent polyester fibers.

[0053] With momentary reference to FIG. 3, a typical cross section of a bicomponent fiber 62 is illustrated. As can be seen in this view, bicomponent polyester fiber 62 has a low melt polyester outer sheath 64 and a high melt polyester core 66 surrounded by sheath 64. As discussed below, during processing, sheath 64 melts off of core 66. Core 66 is thus the same as those high melt monocomponent polyester fibers extruded at extrusion step 54. The melted core material serves as a binder which fuses to adjacent high melt monocomponent polyester fibers to provide added strength as discussed below.

[0054] Returning now to FIG. 1, one the fiber mixture is formed at step 22, it is then ready to undergo a carding process. Optionally, a topical treatment may be applied prior to carding. Topical treatment step 60 may be performed in addition to or in place of the topical treatment applied by application head 34 shown in FIG. 1. This topical treatment may for example be a hydrophilic treatment, e.g. a silicone coating. Alternatively, coatings may be applied during extrusion step 52.

[0055] While illustrated as occurring prior to carding step 58, topical treatment step 60 may also occur after carding step 58. Further, any number of topical treatments could be applied beyond the hydrophilics mentioned above. While silicon advantageously promotes smoothness and glide, it has also been found to promote moisture wicking and moisture vapor transmission. The foregoing qualities achieved via silicone coatings thus also promote the cool feeling of fabric 14. Nevertheless, it is also contemplated that any other coating could be employed which on the one hand is suitable for human contact and on the other promotes moisture wicking and moisture vapor transmission through fabric 14, and possesses desirable smoothness.

[0056] Referring back to FIG. 1, once carding at step 58 is completed, a fiber web 10 is formed which is ready to be hydroentangled using hydroentangling arrangement 24. Fiber web 10 may be fed via any conventional webbing conveying arrangement, e.g. rollers, to hydroentangling arrangement 24. As introduced above, hydroentangling arrangement includes a plurality of hydroentangling jets 26 and a plurality of hydroentangling rollers. Jets 26 act upon fiber web 10 in the region of rollers 28 to entangle adjacent fibers of fiber web 10, thereby forming a hydroentangled web 12. Hydroentangling arrangement 24 may be any contemporary system used for hydroentanglement applications to form nonwoven fabrics.

[0057] Hydroentangled web 12 may then receive a topical treatment via applicator head 34. Applicator head 34 may apply the same or similar substances as those described above relative to optional topical treatment step 60 shown in FIG. 2. It should also be noted that applicator head 34 may include multiple heads to apply treatments to both sides of hydroentangled web 12. Hydroentangled web 12 is then dried via a drying oven 38. Drying oven 38 may be set to a temperature which not only dries hydroentangled web 12, but also activates or melts outer sheath 64 of the bicomponent polyester fibers 62 (See FIG. 3). Alternatively, drying oven 38 may be set to a temperature high enough to dry hydroentangled web 12 to a desired moisture percentage. For example, hydroentangled web 12 may be dried to less than about 7% moisture. As another example, hydroentangled web 12 may be dried to not greater than about 2% moisture.

[0058] After drying, hydroentangled web 12 enters a roller arrangement 42. Roller arrangement 42 includes compaction rollers for compacting hydroentangled web 12 to a desired thickness and density. These compaction rollers may be embodied by heated calendar rolls which serve to compact hydroentangled web 12. The temperature of such calendar rolls may be such that the same activate outer sheath 64 of bicomponent polyester fibers 62 such that the above described binding properties of melted sheath 64 are achieved simultaneously while compaction occurs.

[0059] It should be noted that the above mentioned calendar rollers of roller arrangement 42 have a high degree of smoothness to provide an ironing like effect to hydroentangled web 12 to produce a smooth, drapable fabric 14 which is soft to the touch and suitable for skin contact. Once compaction is complete, fabric 14 is produced. Fabric 14 may then be taken up in bulk on a winding roll 44. Thereafter, subsequent operations may be performed on fabric 14 to form the same into a product as discussed below.

[0060] Turning briefly to FIG. 4, the same illustrates an exemplary cross section taken through the thickness of fabric 14. As can be seen therein, core 66 is bonded or attached to adjacent monocomponent polyester fiber 68 via the melted sheath material 64. This configuration advantageously adds strength to fabric 14, which in turn promotes abrasion resistance, resistance to pilling, density, and provides added strength for subsequent stitching, embossing, or other steps necessary to produce a product from fabric 14.

[0061] As stated above, core material 66 is configured such that it is highly similar or the same as the base monocomponent polyester fibers in terms of fiber diameter, melting point, tensile strength, etc. In effect, the resultant fabric 14 is a grouping of highly similar or identical monocomponent polyester fibers bound to one another via a binder formed via melted sheath 64. Notably, this binding functionality is achieved via the low melt polyester of sheath 64. No solution or emulsion chemical binders are required. Put differently, fabric 14 is free of topical binding chemistry. Such a configuration advantageously avoids the need to remove any chemical by products which may not be suitable in the final product. Further, such a configuration advantageously avoids the need for an additional chemical binding step. Instead, fiber-to-fiber binding is achieved simultaneously during drying and/or compaction as discussed above.

[0062] Turning now to FIG. 5, the same illustrates an exemplary product formed using fabric 14. In the illustrated example, the product is a bed sheet 80. Bed sheet 80 includes an embossed hem region 82 having a height H to aid in the orientation of sheet 80 in bed. This embossed hem region 82 may include a decorative pattern, and may be provide prior to winding onto roller 44. Indeed, this embossed hem region 82 may be applied via an embossing roller forming a part of roller arrangement 42. Alternatively, hem region 82 may be embossed subsequently during the formation of fabric 14 into sheet 80. The embossed hem may be produced using a patterned heated calendar, an ultrasonic bonding unit, hydroembossing, or printing.

[0063] Further, sheet 80 may also include a use indicator 84. This use indicator 84 may for example be a color changing indicator which changes color upon contact with human skin or other bodily fluids. This color change could occur in response to a detection of a particular pH associated with human skin (typically a pH value of 5.5) for example. Additionally or in the alternative, such indicators could be incorporated as a stylized pattern 86 such as that illustrated. In either case, the indicators would advantageously allow the staff of a high occupancy facility to quickly determine whether or not sheet 80 has been used and is ready to be collected for recycling.

[0064] To obtain sheet 80, fabric 14 may be unwound from roll 44, cut to length, embossed with hem region 82. Further, indicator 84 can be emplaced and/or stylized pattern 86 could be added. It is contemplated that this could be achieved at the same facility which employs process 20 described above relative to FIG. 1 using a separate or integrated process line for forming the aforementioned product. In an integrated configuration, fabric 14, upon leaving roller arrangement 42, could continue to undergo processing steps to form the same into a product as opposed to being wound on roll 44. Alternatively, fabric 14 may be supplied in roll form on roll 44 to another facility for subsequent processing into products.

[0065] Further, it is also contemplated that sheet 80 may be expeditiously folded. This expeditious folding methodology would be highly useful in high occupancy facilities, allowing staff to quickly place sheet 80 on a bed. This folding methodology contemplates a folding process where sheet 80 is fan folded, rolled in a folded state on a mandrel, and then flattened after removing the mandrel. More specifically, sheet 80 may be repeatedly fan folded moving from the bottom most edge of sheet 80 in FIG. 5, to the top most edge of sheet 80 in FIG. 5 (i.e. towards hem region 82) in a first direction 90. Thereafter, folded sheet 80 may be rolled on a mandrel 92 moving in a second direction 94 perpendicular to the first direction (i.e. from left to right or vice versa in FIG. 5). Thereafter mandrel 92 could be removed and the rolled sheet 80 flattened.

[0066] To unfold sheet 80, a reverse process is employed. Flattened sheet 80 can be situated at the upper corner of a bed and rolled to the other side of the bed, effectively undoing the roll of sheet 80 formed via mandrel 94. Thereafter, the end of sheet could be pulled from the upper end of the bed to the lower end of the bed, thus covering the bed with sheet 80 in an unfolded configuration.

[0067] In addition to sheet 80 as discussed above, it is also contemplated that the fabric of the instant invention may be advantageously employed as a pillow case. Indeed, the same advantages of wicking, drapability, softness, coolness described above are equally achieved by forming fabric 14 into a pillow case. A sheet and pillow case are only two of many examples of the application of fabric 14, and thus should be taken by way of example and not limitation. As discussed above, fabric 14 may be employed in any application where a nonwoven recyclable fabric which has desirable wicking, drapability, softness, and coolness characteristics.

[0068] It also conceived that the above described spunlacing process 20 may instead be a woven process. Indeed, recycled fibers may be achieved via the process shown and described relative to FIG. 2. Thereafter, the fibers may be blended and carded as described above via step 22. The blended fibers may then be subjected to a woven process and achieve the same advantages as described herein.

[0069] All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0070] The use of the terms a and an and the and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms comprising, having, including, and containing are to be construed as open-ended terms (i.e., meaning including, but not limited to,) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., such as) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0071] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.