Elastic composite having cross-directional elasticity and a system and method for making the elastic composite
10434017 ยท 2019-10-08
Assignee
Inventors
- Patrick King Yu Tsang (Tuen Mun, HK)
- Eugenio Varona (Marietta, GA, US)
- Andrew C. Wright (Derbyshire, GB)
- Anne Smid (Wolvega, NL)
Cpc classification
Y10T156/1044
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T156/1066
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T156/1084
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B32B38/00
PERFORMING OPERATIONS; TRANSPORTING
Y10T442/602
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T156/1082
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B32B2307/726
PERFORMING OPERATIONS; TRANSPORTING
A61F13/49014
HUMAN NECESSITIES
A61F13/15593
HUMAN NECESSITIES
Y10T156/1052
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B32B37/142
PERFORMING OPERATIONS; TRANSPORTING
A61F13/49011
HUMAN NECESSITIES
A61F13/15747
HUMAN NECESSITIES
B32B37/18
PERFORMING OPERATIONS; TRANSPORTING
B32B37/12
PERFORMING OPERATIONS; TRANSPORTING
A61F13/15674
HUMAN NECESSITIES
Y10T428/24752
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
Y10T156/10
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
A61F13/49
HUMAN NECESSITIES
B32B37/14
PERFORMING OPERATIONS; TRANSPORTING
B32B37/12
PERFORMING OPERATIONS; TRANSPORTING
A61F13/15
HUMAN NECESSITIES
B32B37/18
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A method of making an elastic composite is described that entails conveying a first sheet of material on a conveyor, and wrapping a section of elastic about the first sheet and the conveyor, thereby applying elastics cross directionally across the first sheets. A second sheet of material is applied onto the first sheet having elastics applied thereon, thereby creating a subcomposite including the first sheet, the second sheet, and elastics sandwiched therebetween, wherein a plurality of elastics extend outward from the one side of the subcomposite, about the conveyor, and return into an opposite side of the subcomposite. The sub-composite is cut through the first and second sheets and the elastics, thereby separating the sub-composite into a first carrier and a second carrier, each carrier including a first material layer and a second material layer, whereby a plurality of spaced apart elastic elements extend from the first carrier to the second carrier, the first and second carriers defining an exposed elastic region therebetween formed by the plurality of spaced apart elastic elements.
Claims
1. A method of processing an elastic composite for incorporation into a disposable absorbent garment, said method comprising: providing said elastic composite comprising: a first nonwoven layered carrier; a second nonwoven layered carrier spaced from the first carrier; and a plurality of mutually spaced apart, cross-directional elastic elements extending generally laterally from the first carrier to the second carrier thereby forming an exposed elastic region therebetween, each carrier including at least a first nonwoven material layer, whereby said plurality of spaced apart elastic elements extend from the first carrier to the second carrier, and wherein the elastic elements have a first end and a second end, each end being secured by one of the layered carriers; and conveying the elastic composite forwardly in a machine direction by engaging the first and second carriers and moving the first and second carriers forwardly in the machine direction; and applying the elastic composite onto a central body of the disposable absorbent garment, thereby elasticizing a portion of the disposable absorbent garment; and wherein providing the elastic composite includes: conveying a first sheet of material; wrapping a section of elastic about the first sheet, thereby applying elastics cross directionally across the first sheet; applying a second sheet of material onto the first sheet having elastics applied thereon, thereby forming a subcomposite including the first sheet, the second sheet, and elastics sandwiched therebetween, wherein the elastics extend outward from one side of the subcomposite and encircle to return on an opposite side of the subcomposite; and cutting the sub-composite through the first and second sheets and the elastics to generate the elastic composite having two separated parts of the sub-composite and the exposed elastic region therebetween; and wherein said cutting includes separating the sub-composite into said first carrier and said second carrier, each carrier including a first material layer and a second material layer, whereby a plurality of spaced apart elastic elements extend from the first carrier to the second carrier, the first and second carriers defining the exposed elastic region therebetween.
2. The method of claim 1, wherein said conveying the elastic composite includes directing the first and second layered carriers in divergent forwardly directions, thereby extending a lateral width of the elastic region.
3. The method of claim 1, further comprising applying a material sheet over the elastic region during said conveying the elastic composite, thereby generating an elasticized central region having at least one material layer.
4. The method of claim 1, wherein said conveying a first sheet conveys the first sheet of material on a conveyor and said wrapping wraps the section of elastic about the first sheet and the conveyor.
5. The method of claim 1, further comprising: applying a sheet of material onto one side of the elastic region and applying a second sheet of material onto a second side of the elastic region, thereby creating a multilayered laminate having the two material layers and cross directional elasticity; and slitting the laminate along one or more slitting lines to separate therefrom, a plurality of multi-layer elastic composites.
6. The method of claim 5, wherein the material layers are non-woven material layers, and wherein at least one of said applying a first sheet and applying a second sheet includes applying adhesive to multiple designated areas of one or more of the sheets of material such that the resulting laminate includes adhered areas of the elastic region corresponding to the designated areas wherein the two nonwoven material layers mutually adhere to sandwich a plurality of elastics therebetween and non-adhered areas wherein the nonwoven layers are not mutually adhered; and wherein said slitting includes slitting the laminate along the non-adhered areas to divide the non-adhered area and sever the elastics within the non-adhered area, such that each of the plurality of said multi-layer elastic composites includes a central elastic region corresponding to an adhered area and non-elastic zone adjacent the central elastic that corresponds to portion of a non-adhered area among said non-adhered areas.
7. The method of claim 5, wherein said applying a second sheet includes prefolding at least two sections of the sheet of material prior to contact with the elastic region, such that the resulting laminate includes at least two folded flaps above the plurality of elastics; and wherein said slitting includes slitting the laminate along the folded flap to sever the elastics beneath the folded flap, said method further comprising: unfolding the folded flaps of each of the resulting cross-directional elastic composites to reveal a non-elastic zone therein, the non-elastic zone being positioned adjacent a multi-layered elastic region.
8. The method of claim 5, further comprising cutting said laminate along the machine direction proximate each carrier to sever said carriers from said laminate.
9. The method of claim 1, wherein said applying said elastic composite onto said central body includes, forming a disposable absorbent article having a topsheet, backsheet, an absorbent core therebetween, and a central body defined, at least partly, by the topsheet and backsheet, the central body having opposing waist regions along each of two waist end edges that are longitudinally spaced apart and define the longitudinal length of the central body; and wherein said forming the disposable absorbent article includes affixing said elastic composite along one waist end edge of said central body, thereby elasticating a waistband portion.
10. The method of claim 9, wherein said affixing includes extending said elastic composite such that said carriers extend past side margins of the central body, thereby providing waist fastening regions.
11. The method of claim 1, further comprising: providing a backsheet of the disposable absorbent article; and applying a topsheet to said backsheet, thereby forming a central body of the disposable absorbent article having said central body and a pair longitudinally spaced part waist regions each including a waist end edge of the central body; and wherein said applying said elastic composite includes applying said elastic composite on said backsheet prior to said applying said topsheet, wherein said elastic composite is situated between said topsheet and backsheet along a waist end region.
12. A method of processing an elastic composite for incorporation into a disposable absorbent garment, said method comprising: providing said elastic composite comprising: a first nonwoven layered carrier; a second nonwoven layered carrier spaced from the first carrier; and a plurality of mutually spaced apart, cross-directional elastic elements extending generally laterally from the first carrier to the second carrier thereby forming an exposed elastic region therebetween, each carrier including at least a first nonwoven material layer, whereby said plurality of spaced apart elastic elements extend from the first carrier to the second carrier, and wherein the elastic elements have a first end and a second end, each end being secured by one of the layered carriers; and conveying the elastic composite forwardly in a machine direction by engaging the first and second carriers and moving the first and second carriers forwardly in the machine direction; and applying the elastic composite onto a central body of the disposable absorbent garment, thereby elasticizing a portion of the disposable absorbent garment; and wherein said conveying the elastic composite includes directing the first and second layered carriers in divergent forwardly directions, thereby extending a lateral width of the elastic region.
13. A method of processing an elastic composite for incorporation into a disposable absorbent garment, said method comprising: providing said elastic composite comprising: a first nonwoven layered carrier; a second nonwoven layered carrier spaced from the first carrier; and a plurality of mutually spaced apart, cross-directional elastic elements extending generally laterally from the first carrier to the second carrier thereby forming an exposed elastic region therebetween, each carrier including at least a first nonwoven material layer, whereby said plurality of spaced apart elastic elements extend from the first carrier to the second carrier, and wherein the elastic elements have a first end and a second end, each end being secured by one of the layered carriers; and conveying the elastic composite forwardly in a machine direction by engaging the first and second carriers and moving the first and second carriers forwardly in the machine direction; and applying the elastic composite onto a central body of the disposable absorbent garment, thereby elasticizing a portion of the disposable absorbent garment; and applying a sheet of material onto one side of the elastic region and applying a second sheet of material onto a second side of the elastic region, thereby creating a multilayered laminate having the two material layers and cross directional elasticity; and slitting the laminate along one or more slitting lines to separate therefrom, a plurality of multi-layer elastic composites.
14. The method of claim 13, wherein said conveying the elastic composite includes directing the first and second layered carriers in divergent forwardly directions, thereby extending a lateral width of the elastic region.
15. The method of claim 13, wherein providing the elastic composite includes: conveying a first sheet of material; wrapping a section of elastic about the first sheet, thereby applying elastics cross directionally across the first sheet; applying a second sheet of material onto the first sheet having elastics applied thereon, thereby forming a subcomposite including the first sheet, the second sheet, and elastics sandwiched therebetween, wherein the elastics extend outward from one side of the subcomposite and encircle to return on an opposite side of the subcomposite; and cutting the sub-composite through the first and second sheets and the elastics to generate the elastic composite having two separated parts of the sub-composite and the exposed elastic region therebetween; and wherein said cutting includes separating the sub-composite into said first carrier and said second carrier, each carrier including a first material layer and a second material layer, whereby a plurality of spaced apart elastic elements extend from the first carrier to the second carrier, the first and second carriers defining the exposed elastic region therebetween.
16. The method of claim 13, wherein the material layers are non-woven material layers, and wherein at least one of said applying a first sheet and applying a second sheet includes applying adhesive to multiple designated areas of one or more of the sheets of material such that the resulting laminate includes adhered areas of the elastic region corresponding to the designated areas wherein the two nonwoven material layers mutually adhere to sandwich a plurality of elastics therebetween and non-adhered areas wherein the nonwoven layers are not mutually adhered; and wherein said slitting includes slitting the laminate along the non-adhered areas to divide the non-adhered area and sever the elastics within the non-adhered area, such that each of the plurality of said multi-layer elastic composites includes a central elastic region corresponding to an adhered area and non-elastic zone adjacent the central elastic that corresponds to portion of a non-adhered area among said non-adhered areas.
17. The method of claim 13, wherein said applying a second sheet includes prefolding at least two sections of the sheet of material prior to contact with the elastic region, such that the resulting laminate includes at least two folded flaps above the plurality of elastics; and wherein said slitting includes slitting the laminate along the folded flap to sever the elastics beneath the folded flap, said method further comprising: unfolding the folded flaps of each of the resulting cross-directional elastic composites to reveal a non-elastic zone therein, the non-elastic zone being positioned adjacent a multi-layered elastic region.
18. The method of claim 13, further comprising cutting said laminate along the machine direction proximate each carrier to sever said carriers from said laminate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
(33) Generally, the present invention relates to an elastic composite, and to a system and method for making the elastic composite. More particularly, the invention is directed to an elastic composite having cross-machine or cross-directional elastic or stretch properties. Such an elastic composite is sometimes referred to herein as an elastic composite having cross-directional elasticity and further, as a cross-directional elastic composite.
(34) As described previously, various aspects of the present invention are particularly suited to or for a disposable absorbent garment, such as baby diapers and training pants. To illustrate the invention and preferred embodiments of the invention, much of the following Detailed Description will be provided in the context of such disposable absorbent garments. It is contemplated that various aspects of the inventive composite, garment, system, and process may be applicable to other material structures and processes. This Detailed Description and exemplary embodiment should not, therefore, be construed as limiting the invention to the structures, configurations, methods, and processes described herein.
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(36) In
(37) The disposable absorbent garment 110 in
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(39) Along a lateral direction, the diaper 110 includes ear regions or ear portions 118 extending laterally from the waist regions 112, 114. Together, the waist regions 112, 114 and crotch region 116 may be referred to as forming a central body portion 120 of the garment 110 that is positioned within side edges 144, 146. The body portion 120 may also be referred to as being formed by a liquid permeable inner layer or topsheet 152, a liquid impermeable outer layer or backsheet (not shown), and an absorbent core 154 sandwiched between the two layers. The ear portions 118 further include fastening tabs 124 for attaching the waist regions 112, 114 together. The diaper 110 also has an elastic waistband 130 positioned generally along the back edge 142 to facilitate fastening and to enhance the fit and seal of the diaper 110. When the hourglass shaped diaper 110 is worn, the crotch region 116 fits about the crotch of the wearer, and the front and back waist regions, 112 and 114, fit about the corresponding waist areas. The ear portions 118, on the other hand, wrap about the wearer and the fastening tabs 124 engage to form a complete, all-around waistline of the diaper 110.
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(41) As used herein, the term machine direction refers to the direction at which the component, or more particularly, the material web from which the elastic composite is derived (e.g., cut from) is driven in an assembly line during manufacturing. The term cross-machine direction or cross-directional, on the other hand, refers to the direction that is transverse to the machine direction. With reference to the elastic composite 210 of
(42) The elastic composite band 210 has a central region 214 in which an elastic construction 214 is situated. Extending laterally from this central elastic or elasticized region 214 are regions 216 and 218, which are substantially non-elasticized (dead zones). As shown in
(43) The elastic strands 322 may be substituted by suitable elastic elements such as elastic strands, threads, ribbons, and elastic glue beads. The elastic elements or strands 322 are distributed along a direction that extends between the side edges 210a, 210b and generally parallel with (or corresponding to) centerline LL. Further, each elastic element 322 is generally aligned or oriented in a direction corresponding with the lateral or cross-machine direction, i.e., in a direction generally perpendicular to the longitudinal center line LL and intersecting the side edges 210a, 210b (i.e., cross-directional). Preferably, the elastic elements 322 are disposed in generally parallel relation and spaced apart generally equally along the longitudinal direction. More preferably, the elastic elements 322 are of generally equal length. Accordingly, when the elastic composite band 210 is worn, the elastic elements 322 impart elasticity to the structure which allows the band 210 to stretch in the lateral or cross-machine direction XX. Because the elastic elements 322 are independent, spaced apart and maintained along the generally lateral direction, the stretch and contraction of the elasticized material are generally cross-directional. This alternative may be functionally and aesthetically advantageous in some garment applications.
(44) The elastic elements 322 are preferably tensioned during securement between the top and base layers 318, 320.
(45) Returning to
(46) The disposable absorbent garment 110 in
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(48) Before describing the elastic composite of the invention,
(49) Central to the system 1001 is a conveyor assembly 1009 for receiving, manipulating, and conveying each of the non-woven web inputs. The conveyor assembly 1009 is positioned and operatively associated with an elastic element applicator such as a spinning head assembly 1007. The assembly 1007 applies elastic fibers or strands upon, onto, and/or integrally with the non-woven web inputs. The spinning head assembly 1007 further includes a spinhead 1017, preferably in the form of a spinning bracket, or cylinder 1017 and the like. The spin cylinder 1017 is configured to hold an end section of the continuous strand WW of elastic and move it about a generally vertical plane XX in a reciprocal or repetitive pattern (relative to the conveyor assembly 1009). This plane XX is defined by the area within the spinning perimeter of the cylinder 1017 and which is traced by the outer most bracket or eye 1017b securing the strand of elastic WW to the spin cylinder 1017. The paths of the spinhead 1017 and the section of elastic strand retained thereby are provided on the plane XX.
(50) As shown in the schematic of
(51) The conveyor assembly 1009 is set up so as to guide these two non-woven webs 1003a and 1003b through the center of the assembly 1009 towards and eventually inside the elastic spin cylinder 1007 (into the spinning path). Once inside the spin cylinder 1017 the conveyor assembly 1009 delivers the non-woven webs to each outside, upper and lower faces (outward faces) of the conveyor assembly 1009. At this point, the direction of travel of the non-woven webs is reversed and the webs are directed outward from the spin cylinder 1007. As the non-woven webs exit the spin cylinder 1017, an elastic strand WW is wrapped around the entire conveyor assembly 1009, and as it contacts the upper and lower face of the web platforms it comes into contact with the non-woven web. As shown in several of the Figures, the elastic strand WW is applied crosswise or laterally on the web, and transverse to the direction of the moving web. The friction between the tensioned elastic strand and the non-woven webs on the upper and lower faces of the conveyor assembly draws the wrapped elastic strand out of the spin cylinder 1017 and towards contact with two further non-woven webs 1003c and 1003d.
(52) The non-woven webs 1003c and 1003d are operatively positioned upstream of an adhesive applicator 1013. Utilizing a system of rollers in conjunction therewith, the non-woven inputs 1003c, 1003d and adhesive applicators 1013 apply a web of pre-glued non-woven material onto the conveyor assembly 1009 and onto the elastic strand wrapped around the non-woven webs 1003a and 1003b.
(53) Furthermore, the system 1001 employs a standard elastic input source, e.g., a bobbin of elastic yarn, that feeds elastic strands or fibers WW onto a tensioning/speed controlling unit 1037 and then to the spin cylinder or the spinning head 1017, so as to apply the strands WW onto the conveyor assembly 1009 and the non-woven material webs conveyed therethrough. Elastic is taken off the bobbin, box or positive drive system and fed through a tension and speed controlling motor towards the spin cylinder 1017. The elastic WW is delivered through a hollow shaft in the motor controlling the spin cylinder 1017. The elastic WW then passes into the spin cylinder 1017 and is guided by rollers, eyes or any other suitable mechanism around the inside face of the spin cylinder 1017.
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(55) Referring to
(56) At stage B, non-woven webs 1 and 2 are folded prior to being directed to the conveyor assembly 1009. A predetermined width of non-woven is folded over each side of the web to make two folded flaps VV. The width of the flap VV determines the width of the dead zone or non-elasticized region described previously, while the width of the non-woven, after folding, determines the width of the elasticized region. At stage C, the non-woven webs 1 and 2 are fed into the conveyor assembly 1009, in particular into the middle or inside of the conveyor assembly 1009 with the folded side of each web facing the outside of or away from the conveyor assembly 1009. It should be noted that at this stage C, non-woven webs 1 and 2 are not bonded together. The conveyor 1009 then feeds the non-woven webs 1 and 2 towards the spinning head assembly 1007. At stage D, the non-woven webs 1 and 2 have traveled almost the length of the conveyor assembly 1009 and progresses into the spinning path of spinning head assembly 1007 and intersecting the spinning vertical plane XX of the elastic strand WW. Further, at the end of the conveyor assembly 1009, the webs 1 and 2 are directed away from each other and onto the outside of the conveyor 1009 and away from the spinning head 1007. Non-woven web 1 turns up on the upper side of the conveyor assembly 1009, while non-woven web 2 travels along the lower side of the conveyor assembly 1009. At stage E, an elastic strand WW is wound around the folded non-woven webs 1 and 2, as these webs pass through the spinning head and the vertical plane XX. The elastic strand WW is applied to the moving webs 1 and 2 cross-directionally to the direction of the moving web. The movement of the webs 1 and 2 away from within the spin cylinder 1017 draws the wrapped elastic strand out of the spin cylinder 1017.
(57) Now turning to non-woven webs 3 and 4, these webs are provided to the conveyor assembly 1009 with adhesive applied on one side (i.e., applied by the adhesive applicator 1013). At stage F, the non-woven webs 3 and 4 are brought into contact with webs 1 and 2, respectively, and the elastic strands WW. As a result, the webs 1 and 3 sandwich elastic strands WW on the upper side of the conveyor assembly 1009, and non-woven webs 2 and 4 sandwich elastic strands WW on the under side of the conveyor assembly 1009. The elastic strands WW run between the two non-woven elastic non-woven composite (cross-direction), but is then cut by a knife (see knife 1410 in
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(59) As shown in
(60) As shown in
(61) By pre-folding the two non-woven webs that are fed to the inside of the conveyor assembly 1009, it is possible to create an elastic composite with cross directional stretch having non-elasticized regions (dead zones) along each edge. The width of the central elasticized region is fixed to the width of the conveyor platform 1412. The width of the non-elasticized regions or dead zones is determined by the width of the fold VV. The fold VV in the non-woven is preserved by the conveyor assembly 1009 during application of the elastic element and is applied in such a way that the folded edge of the non-woven is not in contact with the elastic element WW. The fold VV is then allowed to open after the composite exits the conveyor assembly 1009 to provide a flat elastic composite with non-elasticized regions. By altering the alignment of the materials as it enters the conveyor assembly 1009 or by changing the widths of the materials used it is possible to create various composite designs.
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(63) The focus of the remaining descriptions shifts now to an alternative and, for some applications, improved system and process for producing an elastic composite having a plurality of mutually spaced-apart elastic elements, and, more preferably, such an elastic composite having cross-directional elasticity.
(64) As discussed previously, the term elastic composite is used to refer to a multi-component material construction that includes elastic elements. In some embodiments, the elastic components include one or more nonwoven layers and elastic elements that impart elasticity on the nonwoven layer(s). In further embodiments, such an elastic composite is in a form suitable for direct integration as a component in a disposable absorbent article. Such an elastic composite may be fed directly into a system and main process for making a disposable absorbent article. In other embodiments, the elastic composite is in a form that is well suited for further processing before integration as a component in a disposable absorbent article. For example, the elastic composite provided herein may be a novel construction that captures the target cross-directional elastic properties of a plurality of elastic elements and provided in a form that facilitates further processing. In one further example, the elastic composite is a novel laminate construction that captures a desired multi-layered elastic construction and in a form that can yield a plurality of individual cross-directional elastic composites in ready form. In other examples, the novel laminate construction is further processed to yield individual cross directional elastic composites having a multilayered central elastic region and, in a further embodiment, a pair of non-elastic regions or dead zones.
(65) With the methods of manufacturing discussed earlier, particularly in respect to
(66) To facilitate description of an elastic composite according to the present invention,
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(68) A comparison of the elastic composite 1210 with the earlier elastic composite 1110, as depicted in
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(70) A system 1350 suitable for the preferred embodiment includes a first nonwoven input I1 (or other suitable material), a second nonwoven input I2 (or other suitable material), and a web output O1 of a continuous elastic composite 1310 according to the preferred embodiment. The first nonwoven input I1 provides or feeds a web or roll (not shown) of a first nonwoven layer 1303 (or other sheet of material), while the second nonwoven input I2 provides or feeds a web or roll (not shown) of a second nonwoven layer 1303. The nonwoven layers 1302, 1303 ultimately provide upper and lower composite layers for each of the two carriers 1212, 1213 of the elastic composite 1310. The system 1350 further includes an output assembly or reel (not shown) to receive the continuous web of elastic composite 1310 or output O1 and, in some applications, direct the output O1 into a main manufacturing process.
(71) Central to the system 1350 is a conveyor assembly 1309 for receiving, manipulating, and conveying the nonwoven web inputs I1, I2 as well as the elastic composite output O1. As described previously, the conveyor assembly 1309 preferably includes an upper conveyor and platform (hereinafter upper conveyor 1314) and a lower conveyor and platform (hereinafter lower conveyor 1315). Referring to
(72) The conveyor assembly 1309 is operatively associated with a suitable elastic element applicator such as a spinning head assembly 1307 and spin head 1317 (elastic spinners), as described previously. The spin head 1317 extends slightly over and about the ends of the two conveyors 1314, 1315, and is configured to hold an end section of a continuous elastic strand WW of elastic. Revolution of the spin head 1317 moves the end section about a generally vertical plane VV and about the conveyor assembly 1309. The vertical plane VV preferably has a diameter that is just slightly less than the inside diameter of the spin head 1317. The vertical plane intersects the conveyors 1314, 1315 and further, webs moving on the conveyors 1314, 1315. As generally known, the two conveyors 1314, 1315 reciprocate such that the inside platform surface moves linearly toward and past the vertical plane VV in a first web moving direction V1, before turning as the outside platform surface. The outside platform surface moves linearly past the vertical plane VV in a second web moving direction V2 that is the reverse of the first web moving direction V1. The path of the outside platform surface is spaced outwardly of the path of the inside platform surface and in generally parallel relation therewith.
(73) In accordance with a preferred embodiment, a first nonwoven carrier web 1303 is directed to the conveyor assembly 1309. The conveyed web 1303 is then conveyed by the upper conveyor 1314 along the first web moving direction V1 and through the vertical plane VV. After arriving at the end of the conveyors 1314, 1315, the nonwoven carrier web 1303 is passed onto the top conveyor 1314 as shown in
(74) Noting that the section of elastic WW is applied across the outside surface of the lower conveyor 1315 as well, the moving conveyors 1314, 1315 draw continuous strand WW away from the spin head 1317. The new substrate now consisting of the nonwoven web 1303 and the elastics applied thereon is subsequently met by a second nonwoven web 1304. The second nonwoven web 1302 is directed onto and in union with the upper conveyor 1315a and atop the substrate of the first nonwoven web 1303 and elastics applied thereon. As generally known, the second nonwoven carrier web 1304 is preferably applied with a process adhesive upstream of the upper conveyor 1315a. The adhesive is sufficiently applied to provide a secure bond between the two nonwoven carrier webs 1302, 1303 and the elastics therebetween. In alternate embodiments, another suitable process or means of bonding the layers and elastics may be employed (e.g., thermal bonding, ultrasonic bonding, embossing, etc.)
(75) Thus, a new composite or subcomposite is provided as a result of the union of several components. This union includes: a first nonwoven web 1303 supported on the outside surface of the upper conveyor 1314; a section of elastic strand WW applied across the first nonwoven web 1303 multiple times; and a second nonwoven web 1302 applied atop the first nonwoven web 1303 and the elastics applied thereon. As shown in
(76) Referring specifically to
(77) In one aspect of the preferred embodiment, an elastic composite 1210 is provided having an exposed elastic construction or open elastic region 1204 formed by the plurality of mutually spaced apart elastic elements 1201, as shown in
(78) The width of the open elastic region 1204 is also dependent on and provided by the extension state of the elastic elements when the measurement is taken. Generally, the important reference measurements are those made when the elastic elements are fully relaxed (extension factor equals 1), and measurements taken when the elastic elements are fully extended (typical extension factor equals 4 to 6, depending on the type of elastic used).
EXAMPLE 1
(79) In one embodiment of the invention, the width of open elastic region may be approximated as follows:
(80) Given, conveyor width, W=100 mm;
(81) distance, d, from upper surface of upper conveyor to lower surface of lower conveyor=40 mm;
(82) extension applied to continuous elastic strand=4;
(83) full extension of elastics=5.
(84)
EXAMPLE 2
(85) In a more preferred embodiment, the width of the open elastic region is increased by reducing the extension applied to the elastic strand as it is applied to the nonwoven carrier web. The circumference of the conveyor assembly is also increased by increasing the separation of the upper and lower conveyors. In some suitable systems, one of the conveyor platforms is simply moved further from the other platform. It should also be noted that one of the conveyors is not required to move a sheet of material, but only the elastic wrapped about it. This allows for use of conveyors different from the generally flat platforms or belts commonly used to support a sheet of nonwoven.
(86) Given, conveyor width, W=100 mm,
(87) distance, d, from upper surface of upper conveyor to lower surface of lower conveyor=100 mm,
(88) extension applied to elastics=1.5,
(89) full extension of elastics=5.
(90)
(91) Examples 1 and 2 above illustrate that the width of the open elastic area may be adjusted by making small changes to the applied extension of the elastics and to the dimensions of the conveyor assembly. In certain embodiments, the tension is determined by the feed rate of the elastic strands into the spin head and the frictional characteristics of the feeding and spinning process. The circumference can be varied mechanically by changing the distance between the upper and lower conveyors.
(92) Notably, the elastic composite 1210 is characterized by mutually spaced apart, cross-directional elastic elements 1201 that extend laterally between the first and second carriers 121, 1213 and in transverse relation with the machine direction of the elastic composite (LL). Each of the layers 1202, 1203 of the carriers 1212, 1213 preferably extends generally longitudinally in generally parallel relation with the machine direction LL and has a lateral width that is substantially less than a lateral width between the first and second carriers 121, 1213 (across the open elastic region 1204). In a further aspect, the elastic elements 1201 of the open central elastic region 12104 are discrete disconnected segments of one elastic strand. This means that the elastic elements 1201 originate from the same elastic strand and are, in fact, severed sequentially from the same elastic strand while that strand is in a generally uniform state of tension or application (e.g., secured in tension between adhered nonwoven layers). Being discrete disconnected segments of one elastic strand further means that the elastic elements have substantially identical material and mechanical properties (particularly, dimensions, strength, and elastic properties). The inclusion of such elastic elements can offer benefits in the ultimate elastic composite as well as the processes in the making of the elastic composite. For example, having uniformity and consistency in the plurality of elastic elements facilitates handling of the elastic composite, provides a cleaner and more aesthetically pleasing gathering in the ultimate disposable absorbent article, and may also produce a better quality product with less flaws.
(93) Exemplary ApplicationsPost Processing
(94) A variety of applications for the cross directional elastic composite 1210 and output composite 1303, O1 described above are contemplated. These applications include direct incorporation of the elastic composite 1210 (having the open elastic region) as a component in a disposable absorbent article and particularly, into a process of making the article. For example, the elastic composite 1210 may be integrated as a wide elastic waistband of a diaper type product. The elastic composite 1210 may also be applied as a body encircling elastic component for training pants.
(95) A cross directional elastic composite with open elastic region is also well suited for further processing prior to integration into a disposable absorbent article.
(96) In accordance with a preferred method, the output O1 (continuous web of elastic composite 1310) of system 1350, as described in respect to
(97) The tensioned elastic composite O1 is then fed to a laminating stage, wherein a lower nonwoven web 1503 is continuously directed to the web O1 from below and an upper nonwoven web 1502 is continuously directed to the web O1 from above. Prior to reaching the web O1, hot melt adhesive is applied to each of the nonwoven webs 1502, 1503 using suitable adhesive application equipment 1616. Thereafter, the lower nonwoven web 1503 is applied to the underside of open elastic region 1504 of the web O1 and the upper nonwoven web 1502 is applied to the topside of the open elastic region 1504. The applied adhesive ensures proper bonding between the nonwoven layers and the tensioned elastic elements. The resulting laminate 1511 includes, therefore, an upper nonwoven layer 1502, a matching lower nonwoven layer 1502, 1503, a pair of carriers 1512, 1513 providing the side borders of the laminate 1511, and a plurality of mutually spaced apart elastic elements 1501 extending between the carriers 1512, 1513 and sandwiched between the nonwoven layers 1502, 1503. As compared to the output web O1, the elastic elements 1501 are now in an extended state, but remain laterally oriented, thereby imparting cross-directional elasticity to the laminate 1511.
(98) Notably, the two carriers 1512, 1513 serve a handling function during the process. The carriers 1512, 1513 ensure that the configuration of elastic elements is maintained as the webs O1, O1 are processed. The carriers 1512, 1513 also provide a solid base for the components of the system 1601 to secure and handle (e.g., convey and stretch) webs O1, O1.
(99) As shown in the exemplary diagram of
(100) Elastic Composites Having Dead Zones
(101) In further embodiments, the preferred elastic composite is equipped with a pair of non-elasticized regions or dead zones, the utility of which has already been described. As generally known, the dead zones are preferably situated on either lateral side of a central elastic region having an elastic construction (as discussed previously). Various ways are envisaged to create the dead zones within methods of making the elastic composite according to the invention. In one exemplary method, an adhesive pattern is applied to the nonwoven web input. The adhesive pattern is selectively applied so that adhesive is provided only to areas of the nonwoven web wherein the elastic strands are to be retained.
(102) To illustrate,
(103) In the illustrated embodiment, a non-adhered area B is located adjacent each of the two carriers 1512, 1513 and a slitting line SS is aligned along the inside of the carrier 1512, 1513. As a result, the carrier 1512, 1513 is cut and removed from the web during the slitting process. The formerly adjacent non-adhered area B remains as a dead zone of the resulting cross-directional elastic composite.
(104)
(105) Alternative Systems and System Components
(106)
(107) The extender 2002 employs a suitable conveying means in the form of a pair of endless belts or mechanical chains 2021, as shown in
(108) At point C, the carriers 1312, 1313 are released by the engagement means 2007 and then conveyed to a subsequent, post-processing operation. The two endless chains 2021 are passed along generally convergent directions through points D to F before returning to point A.
(109)
(110) Other carrier engagement and gripper systems that may be used include a friction belt system, wherein the carrier is sandwiched between two belts and driven by the moving belts. In yet other embodiments, the engagement means may grip the carrier by way of a vacuum that secures the moving carrier to the periphery of each of a pair or set of reciprocating drums or wheels. In one example, the outside of the drums or wheels may be provided with perforations that fluidly communicate with an internal volume or medium that is at vacuum pressure.
(111)
(112)
(113) The pattern or application of elastics on the output web O1, and ultimately, on the resultant elastic composite 1310 may be altered in yet another way, as provided by the system shown in
(114) In further embodiments, the pitch of the elastics in the elastic composite may be varied to achieve desired functionality.
(115) It is further noted that, with this embodiment, the speed of the process may be increased (doubled) relative to the single feed process, while maintaining the same number of elastic strands per unit length of the composite and without increasing the speed of the spinhead (but, by increasing the speed of the conveyor). Alternatively, the number of elastic strands per unit length may be increased (doubled) relative to the single feed process with the spinhead speed and conveyor speed unchanged.
(116) In one particular application, the sections are cut such that the region proximate one cutting edge is generally provided with elastics at a higher pitch and thus, higher elasticity, while the region proximate the opposite edge is generally provided with elastics at reduced pitch and thus, at reduced elasticity. Such an elastic composite may be suited for application and use as waistband or side panel, wherein the region of higher elasticity is positioned along a top waist edge of the disposable absorbent article. In another embodiment, such an elastic composite and placement provide a combination waistband and side panel (see e.g.,
(117)
(118) In these applications, the elastic composite 1310 is implemented to impart elasticity to both the waistband and side panels of the disposable absorbent article 2710. In
(119) In a typical manufacturing process, the elastic composite band is secured over the topsheet of the central body using suitable adhesive means and the like. As compared to conventional constructions, the combination waistbandside panels of the invention achieves a reduction in attachment steps and attachment points. In conventional constructions, each of the two side panels and the waistband is a separate multi-ply composite attached to a portion of the central body. Accordingly, the simpler construction of the combination waistbandside panel of the invention also provides materials cost savings. Furthermore, use of the elastic composite as a waistband replaces the need for and use of much more expensive elastic film or frame.
(120) In a further embodiment illustrated by
(121) In an alternative design, both the topsheet and the backsheet of the central body of the disposable absorbent article are pre-shaped or pre-cut to provide regions that outline the side panel. The elastic composite of the invention is simply attached onto the backsheet (or topsheet), and then the topsheet (or backsheet) is laid over the elastic composite. Suitable adhesive means is used to secure the multi-layered composite. The carriers of the elastic composite, if still present, may be trimmed off to refine the shape and look of the side panel. Accordingly, a combination waistband and side panels is formed more integrally with the central body of the disposable absorbent article.
(122) The use of the inventive elastic composite to form a combined waist and side panel provides certain important advantages over systems utilizing separate elastic materials as the side panel and waist elastic. Firstly, the elastic elements that form the elasticizing function of the waist panel and the side panels are the same, and as such, there is a continual connection of elastic material from one side panel to the opposite side panel as discussed above. As a result, any lateral force applied to the side panels is carried through and directly exerted around the waist of the wearer. This achieves added comfort for the wearer, and helps maintain the article in the correct position about the wearer. Moreover, the improve fit of the article about the wearer along with the reduction of attachments and adhered areas, improves the water-tight seal between the body of the wearer and the article.
(123) The inventive combination waist panel and side panel also provides significant cost savings. The nonwoven carriers may be utilized as the side panel upon which a fastening element can be affixed. The elastic strands held between the nonwoven side edges provide the elastic material to elasticize the waist and side panels. The elastic composite allows for a practical and efficient way to process and place cross-machine direction strands in the waistband and side panel regions of the article. Using elastic strands in this way is far more cost efficient than using a stretchable film, foam or nonwoven for the waistband and/or side panels. Among other reasons, conventional films or foams are significantly more costly than elastic strands.
(124) The foregoing description of the present invention has been presented for purposes of illustration and description. It is to be noted that the description is not intended to limit the invention to the various systems, apparatus, and processes disclosed herein. Various aspects of the invention, as described above, may be applicable to other types of disposable absorbent articles, garments, and the like, and processes for making the same. For example, the elastic composite described above, may be incorporated in other disposable absorbent garments such as training pants, etc. or in other areas or as other components of the garment. The elastic composite may also be incorporated into or with other garments, textiles, fabrics, and the like, or combinations thereof. The elastic composite may also incorporate different components. For example, the common use of nonwoven webs for the top and/or bottom sheet material may be replaced with use of another material such as a film material. Moreover, the various aspects of the process described in respect to