Mechanical fasteners, fastening devices, and disposable absorbent articles

Abstract

A mechanical fastener is disclosed that includes a thermoplastic backing and a plurality of upstanding fastening elements having a post with a proximal end attached to the thermoplastic backing and a distal end including a cap having an area larger than the cross-sectional area of ​​the post. The mechanical fastener has a basis weight ranging from 25 grams per square meter to 75 grams per square meter, and the plurality of upstanding fastening elements are up to 300 micrometers. Also disclosed are a fastening system and an absorbent article including the mechanical fastener.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application Nos. 61 / 535,639, filed September 16, 2011, and 61 / 654,492, filed June 1, 2012, the entire disclosures of which are incorporated herein by reference. [Background technology]

[0002] Mechanical fasteners, also known as hook and loop fasteners, typically comprise multiple closely spaced upstanding projections with loop-engaging heads useful as hook members, while loop members typically comprise multiple woven, nonwoven, or knit loops. Mechanical fasteners are useful for providing releasable attachment in numerous applications. For example, mechanical fasteners are widely used in consumable disposable absorbent articles to fasten such articles around the human body. In a typical configuration, a hook strip or patch on a fastening tab attached to the back waist region of a diaper or incontinence garment can be fastened to a landing area of ​​loop material in the front waist region, for example, or the hook strip or patch can be fastened to the backsheet (e.g., a nonwoven backsheet) of the diaper or incontinence garment in the front waist region. Mechanical fasteners are also useful in disposable articles such as sanitary napkins. Sanitary napkins typically include a backsheet intended to be placed adjacent to the wearer's undergarments. The backsheet may be provided with hook fastening elements for securely attaching the sanitary napkin to an undergarment and is in mechanical engagement with the hook fastening elements.

[0003] Hook and loop fasteners can include at least two engagement strength characteristics: peel strength and shear strength. Peel strength corresponds to the force required to release fastening members from one another by peeling one fastening member upward from the other fastening member. Shear strength corresponds to the force required to release fastening members from one another by pulling at least one of the fastening members away from the other fastening member in a plane parallel to the fastening members. Typically, the engagement strength of fastening members is higher in shear than in peel. While peel strength can be a factor in intentionally separating fastening members, shear strength typically plays a role in holding fastening members together during normal use. Summary of the Invention [Means for solving the problem]

[0004] The present disclosure provides mechanical fasteners with a relatively low basis weight compared to conventional mechanical fasteners and fastening systems, as well as disposable absorbent articles equipped with the mechanical fasteners. Reducing the basis weight of the mechanical fasteners reduces manufacturing costs and advantageously reduces the amount of thermoplastic resin wasted when disposable absorbent articles containing the mechanical fasteners are discarded, for example. Despite their low basis weight, the mechanical fasteners disclosed herein have comparable or superior engagement with loop materials as compared to higher basis weight mechanical fasteners, as measured by shear and peel tests. High engagement is observed even with loop materials, even so-called low-loft loop materials, which are frequently used in disposable absorbent articles to reduce the cost and amount of material in disposable absorbent articles. Therefore, the mechanical fasteners disclosed herein can be considered material-efficient. Typically, the mechanical fasteners disclosed herein are soft to the touch on both the first surface having the upstanding fastening elements and the opposing second surface.

[0005] In one aspect, the present disclosure provides a mechanical fastener including a thermoplastic backing and a plurality of upstanding fastening elements having a post with a proximal end attached to the thermoplastic backing and a distal end with a cap having an area larger than the cross-sectional area of ​​the post. The basis weight of the mechanical fastener ranges from 25 grams per square meter to 75 grams per square meter, and the height of the plurality of upstanding fastening elements is up to 300 micrometers. In some embodiments, the basis weight of the mechanical fastener can be 40 grams per square meter (gsm) to 75 gsm, 50 gsm to 75 gsm, or 55 to 70 gsm.

[0006] In another aspect, the present disclosure provides a fastening device including the mechanical fastener described above and a loop material for engaging the mechanical fastener. In some embodiments, the fiber basis weight of the loop material ranges from 10 grams per square meter to 30 grams per square meter.

[0007] In another aspect, the present disclosure provides a disposable absorbent article including the mechanical fastener or fastening system described above.

[0008] As used herein, terms such as "a," "an," and "the" are not intended to refer to only one entity, but include general classes that can be used to illustrate specific examples. The terms "a," "an," and "the" are used interchangeably with the term "at least one." The phrases "at least one of" and "comprising at least one of," followed by a list, refer to any one of the items in the list and any combination of two or more items in the list. All numerical ranges include their endpoints and non-integer values ​​between the endpoints unless otherwise specified.

[0009] The term "upright" refers to posts that protrude from the thermoplastic backing and includes posts that stand perpendicular to the backing and posts that are angled relative to the backing at an angle other than 90 degrees.

[0010] The term "plurality" means more than one and can include any desired number of upstanding fastening elements.

[0011] The terms "first" and "second" are used in this disclosure only in their relative sense, and it will be understood that unless otherwise indicated, these terms are used merely for convenience in describing one or more embodiments.

[0012] The above "Summary" of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The following description more particularly exemplifies exemplary embodiments. Therefore, it should be understood that the drawings and the following description are for illustrative purposes only and should not be construed to unduly limit the scope of the present disclosure. [Brief explanation of the drawings]

[0013] A more complete understanding of the present disclosure can be obtained from the following detailed description of different embodiments of the present disclosure when considered in conjunction with the accompanying drawings. [Figure 1] 1A-1C are side views of exemplary upstanding fastening elements on a thermoplastic backing useful in the mechanical fasteners disclosed herein, illustrating various dimensions of the upstanding fastening elements. [Figure 2] 1 is a perspective view of an exemplary disposable absorbent article including a mechanical fastener according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Reference will now be made in more detail to the embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. Features illustrated or described as part of one embodiment can also be used with another embodiment to yield a third embodiment. The present disclosure is intended to include these and other modifications and variations.

[0015] Referring to FIG. 1 , a mechanical fastener according to the present disclosure includes a thermoplastic backing 14 having a plurality of upstanding fastening elements 11 attached to the thermoplastic backing 14. As shown in the embodiment illustrated in FIG. 1 , the plurality of upstanding fastening elements 11 have a post 10 with a proximal end 10a attached to the thermoplastic backing 14 and a distal end 10b including a cap 12 of greater area than the cross-sectional area of ​​the post 10. The cap 12 extends beyond the post by an overhang distance "o". The height "h" of the upstanding fastening element 11 is the distance between the thermoplastic backing 14 and the distal end 10b of the upstanding fastening element 11 as shown in FIG. 1 . The thickness "t" of the thermoplastic backing 14, the width "w" of the post at its base, and the width "w" of the post just below the cap are taken into account. 1 ", cap width "w 2 " is also shown in Figure 1.

[0016] Various factors affect the basis weight of a mechanical fastener. For example, using a low density thermoplastic polymer reduces the basis weight of the mechanical fastener. Furthermore, the height "h" and width "w" of the upstanding fastening elements affect the amount of material in the mechanical fastener, and therefore the basis weight of the mechanical fastener. In the illustrated embodiment, the amount of material in the cap is determined by the width "w" of the cap. 2 " and also influences the basis weight. The thickness "t" of the backing tends to have a large effect on the basis weight of the mechanical fastener. Typically, the backing thickness "t" of the mechanical fasteners disclosed herein ranges from 20 micrometers (μm) to 80 μm. In some embodiments, the backing thickness "t" ranges from 30 μm to 75 μm, 40 μm to 75 μm, 20 μm to 70 μm, or 30 μm to 70 μm. For use in this application, all dimensions of the upstanding fastening elements described herein with respect to FIG. 1 and in the claims are measured with an optical microscope.

[0017] The height "h" of the upstanding fastening elements is low enough to maintain a basis weight of 75 gsm or less and provide good engagement with loop materials (e.g., low loft loop materials). In mechanical fasteners according to the present disclosure, the upstanding fastening elements 11 have a maximum height "h" of up to 300 μm, and in some embodiments, up to 285 μm, 275 μm, or 250 μm. In some embodiments, mechanical fasteners according to the present disclosure have upstanding fastening elements 11 with a minimum height "h" of at least 40 μm, and in some embodiments, at least 50 μm, 100 μm, or 140 μm. In some embodiments, a mechanical fastener according to the present disclosure has upright fastening elements 11 with a height "h" ranging from 150 μm to 300 μm, 40 μm to 285 μm, 100 μm to 275 μm, 140 μm to 250 μm, 50 μm to 300 μm, 50 μm to 285 μm, 50 μm to 275 μm, 100 μm to 250 μm, 100 μm to 285 μm, 100 μm to 300 μm, 140 μm to 275 μm, or 155 μm to 250 μm.

[0018] Typically, the upstanding fastening elements 11 in mechanical fasteners according to the present disclosure have an aspect ratio (i.e., the ratio of height "h" to maximum width dimension "w") of up to about 2:1, 1.5:1, or 1.2:1. The posts 10 may have a cross-section with a maximum width dimension "w" of at least 100 μm with a maximum width dimension "w" of up to 250 μm. In some embodiments, the posts 10 have a cross-section with a width dimension "w" ranging from 125 μm to 200 μm or from 135 μm to 190 μm. The term "width dimension" should be understood to include the diameter of a post 10 having a circular cross-section. When the post 10 has multiple width dimensions (e.g., posts with rectangular or oval cross-sectional shapes), the aspect ratios described herein are height to maximum width dimension.

[0019] In a mechanical fastener according to the present disclosure, the upstanding fastening element 11 may be made, for example, by any of the methods described below, and may have, for example, a post 10 that tapers from a proximal end 10a to a distal end 10b. The proximal end 10a is shown in FIG. 1 as having a width dimension "w 1In some embodiments, the posts 10 have a width dimension "w" just below the cap that ranges from 100 μm to 200 μm, 120 μm to 195 μm, or 130 μm to 185 μm. 1 ". The tapered shape may allow the post 10 to be easily removed from the mold surface in the manner described below. Furthermore, the aspect ratios mentioned above are height "h" to maximum width dimension "w."

[0020] The mechanical fastening elements described herein typically have a cap that is larger in area than the cross-sectional area of ​​the post. In some embodiments, the cross-sectional area of ​​the post extends beyond the area immediately below the cap (e.g., width "w 1 "). Furthermore, the ratio of the width dimension of the formed cap to the width dimension of the post measured at the proximal end is typically at least 1.01:1 or 1.2:1 and can be up to 2:1. Referring again to FIG. 1, the cap 12 has a maximum width dimension "w" of at least 150 μm and a maximum width dimension "w" of at most 380 μm. 2 In some embodiments, the cap 12 may have a width dimension "w" ranging from 150 μm to 350 μm or from 170 μm to 340 μm. 2 ". The width dimension "w 2 " is measured looking at the cap from above. The term "width dimension" should be understood to include the diameter of a cap 12 having a circular cross section. Cap 12 may have multiple width dimensions (e.g., caps with rectangular or oval cross-sectional shapes), and the "w" dimension may be measured from above. 2 " is measured at the widest point of the cap 12.

[0021] Cap 12" width 2 " and the width of the post 10 towards the distal end 10b is related to the cap overhang "o". Specifically, the cap overhang "o" in the illustrated embodiment is calculated using the formula (cap width "w 2" - the post width at the distal end) divided by two. In some embodiments of mechanical fasteners according to the present disclosure, the overhang distance is a maximum of 90 μm. In other words, the overhang extends beyond the post by a maximum of 90 μm. In some embodiments, the overhang is a maximum of 85, 84 μm, 82 μm, or 80 μm. The minimum amount of overhang can be selected based, for example, on the fiber diameter of the loop selected to engage with the mechanical fasteners disclosed herein. In some embodiments, the overhang is at least 5 μm or 10 μm. The overhang can be, for example, in the range of 5 μm to 84 μm, 5 μm to 80 μm, or 5 μm to 75 μm. In embodiments in which the mechanical fasteners disclosed herein are used to secure pads (e.g., adult incontinence articles as described below), the overhang can be, for example, in the range of 5 μm to 65 μm.

[0022] Mechanical fasteners according to the present disclosure have upstanding fastening elements with the ratio of overhang distance to height "h" calculated above. This ratio is conveniently referred to herein as the "bend index" because it relates to how much the cap or post will bend when the upstanding fastening element is subjected to a shear force. In some embodiments of the mechanical fasteners disclosed herein, the upstanding fastening elements have a bend index of up to 0.6, 0.50, or 0.45. For example, the upstanding fastening elements may have a bend index of 0.02 to 0.6 or 0.05 to 0.5. At a bend index less than 0.02, the post may bend when the mechanical fastener is subjected to a shear force, reducing engagement strength. At a bend index greater than 0.6, the cap may bend when the mechanical fastener is subjected to a shear force, reducing engagement strength.

[0023] Many thermoplastic resin materials are useful in the mechanical fastener according to the present disclosure. Suitable thermoplastic materials for the thermoplastic backing with upright fastening elements include polyolefin homopolymers such as polyethylene and polypropylene, copolymers of ethylene, propylene, and / or butylene, copolymers containing ethylene such as ethylene vinyl acetate and ethylene acrylate, polyesters such as poly(ethylene terephthalate), polyethylene butyrate, and polyethylene naphthalate, polyamides such as poly(hexamethylene adipamide), polyurethanes, polycarbonates, poly(vinyl alcohol), ketones such as polyethyl ethyl ketone, polyphenylene sulfide; poly(acrylonitrile-butadiene-styrene); plasticized polyvinyl chloride; and mixtures thereof. Typically, the thermoplastic resin is a polyolefin (e.g., polyethylene, polypropylene, polybutylene, ethylene copolymers, propylene copolymers, butylene copolymers, and copolymers and blends of these materials). The various thermoplastic materials described above can be formulated into masterbatches having desired properties (e.g., color), although the presence or absence of dyes, pigments, or other colorants is not required by this disclosure.

[0024] In some embodiments, thermoplastic backings with upstanding fastening elements can be made from multi-layer or multi-component melt streams of thermoplastic material. This can result in fastening elements formed at least partially from a thermoplastic material different from that primarily forming the backing. Various configurations of upstanding posts made from multi-layer melt streams are shown, for example, in U.S. Pat. No. 6,106,922 (Cejka et al.). Multi-layer or multi-component melt streams can be formed by any conventional method. Multi-layer melt streams can be formed by multi-layer feedblocks, such as those shown in U.S. Pat. No. 4,839,131 (Cloeren). Multi-component melt streams having domains or regions with different components can also be used. Useful multi-component melt streams can be formed by the use of an inclusive coextrusion die or other known methods, such as those shown in U.S. Pat. No. 6,767,492 (Norquist et al.).

[0025] In mechanical fasteners according to the present disclosure, the thermoplastic backing and the upstanding posts are typically integral (i.e., formed simultaneously as a unit). In some embodiments, the thermoplastic backing and the upstanding fastening elements are made from the same thermoplastic material. The thermoplastic backing is typically in the form of a sheet or web, which may have a substantially uniform thickness, with the upstanding fastening elements attached directly to the thermoplastic backing. The upstanding posts of the backing can be made by die-casting techniques, for example, by conventional extrusion molding. In some embodiments, the thermoplastic material is fed into a continuously moving mold surface having cavities with the inverse shape of the upstanding posts. The height of the posts is measured by the depth of the cavities. The thermoplastic material can be passed between two rolls, at least one of which has a cavity (i.e., at least one of the rolls is a tool roll), i.e., a nip formed by the nip between the die surface and the roll surface. Pressure provided by the nip forces the resin into the cavities. In some embodiments, a vacuum can be used to evacuate the cavities for easier filling. The nip typically has a gap large enough so that a coherent backing is formed over the cavities. The mold surface and cavities may optionally be air or water cooled before the integrally formed backing and upstanding posts are stripped from the mold surface, such as by a stripper roll.

[0026] Suitable tool rolls can be made, for example, by forming a series of holes having the inverse shape of the upstanding posts into the cylindrical surface of a mold or sleeve (e.g., by drilling, photoetching, using a galvanically printed sleeve, laser drilling, electron beam drilling, metal punching, direct machining, or computer numerical control with a lost-wax process). Other suitable tool rolls include those formed from a series of plates defining a plurality of post-forming cavities around their periphery, such as those disclosed in U.S. Pat. No. 4,775,310 (Fischer). The cavities may be formed in the plates by, for example, drilling or photoresist techniques. Still other suitable tool rolls may include wire-wrapped rolls, such as those disclosed, along with their manufacturing methods, in U.S. Pat. No. 6,190,594 (Gorman et al.). Exposed surfaces of the mold, sleeve, plate, or wire can be coated to impart surface properties such as, for example, increased wear resistance, controlled release, and controlled surface roughness. The coating, if present, is preferably selected so that the adhesion of the thermoplastic material to the tool roll is less than the cohesive strength of the thermoplastic material upon removal of the thermoplastic backing from the tool roll.

[0027] Another exemplary method for forming a thermoplastic backing having upstanding posts is described in U.S. Patent No. 7,214,334 (Jens et al.) and involves using a flexible mold belt defining an array of mold cavities in the shape of upstanding posts. The mold belt is guided around first and second rolls, and a source of molten thermoplastic material is configured to deliver thermoplastic material to the mold belt. The apparatus is constructed to force plastic resin into the upstanding post-shaped cavities of the belt under pressure within the gap, forming the array of upstanding posts while forming a thermoplastic web layer.

[0028] The upstanding posts useful in the backing may have various heights above the backing, which may be altered after the capping process described below, for example, to provide upstanding fastening elements of the mechanical fasteners described herein. For example, the upstanding posts may have a maximum height (above the backing) of up to 400 micrometers (μm), and in some embodiments, up to 350 μm or 300 μm. The upstanding posts may have a minimum height of at least 150 μm, and in some embodiments, at least 160 μm or 175 μm. Upstanding posts useful according to the present disclosure may have heights ranging from 150 μm to 400 μm or from 150 μm to 350 μm.

[0029] The posts formed upon exiting the cavities typically have no caps, although caps may subsequently be formed on the upright fastening elements by a capping method such as that described in U.S. Pat. No. 5,607,635 (Melbye et al.). Typically, capping methods involve deforming the distal tip portions of the upright posts using heat and / or pressure. When both heat and pressure are used, they may be applied sequentially or simultaneously. In some embodiments, the deforming step involves contacting the distal tips of the upright posts with a heated surface. The heated surface may be a flat or textured surface, such as those disclosed in U.S. Pat. No. 6,708,378 (Parellada et al.) or U.S. Pat. No. 5,868,987 (Kampfer et al.). In some embodiments, the thermoplastic backing bearing the upright fastening elements is a web of indefinite length, and deforming the distal tips of the posts to form the caps involves moving the web in a first direction through a nip with a heated surface member and an opposing surface member such that the heated surface member contacts the distal tips. In these embodiments, the heated surface may be, for example, a capping roll. In some embodiments, the surface used for contact with the distal tip may not be heated. In these embodiments, deformation is performed by pressure without heat. In some embodiments, the heated surface may be a heated roll facing a curved support surface that forms a variable nip with a variable nip length, as described, for example, in U.S. Pat. No. 6,368,097 (Miller et al.). The curved support surface may be curved toward the heated roll, and the heated roll may include a feeding mechanism for feeding the thermoplastic backing with the upstanding posts through the variable nip to compress and engage the web between the heated roll and the support surface. In some embodiments, heating is performed below the melting point of the distal tip. When the thermoplastic material used to form the upstanding posts is a copolymer (e.g., a copolymer of ethylene and propylene), the distal tip may have multiple melting temperatures. In these embodiments, "below the melting temperature of the distal tip" means below at least one of the melting temperatures.

[0030] In some embodiments, the distal caps of the upstanding fastening elements are reshaped after formation. For example, a thermoplastic backing having an upstanding capped post is passed through the gap nip of a heated rubber roll and a backup roll, so that the overhanging portion of the distal cap extending beyond the post is pressed down toward the backing. This process is described in U.S. Patent No. 6,132,660 (Kampfer).

[0031] In addition to the continuous methods described above, the thermoplastic backing having upstanding fastening elements may also be prepared using a batch process (e.g., single injection molding). The thermoplastic backing may have any suitable dimensions, although length (L) and width (W) dimensions of at least 10 centimeters may be useful.

[0032] Another method for forming a thermoplastic backing with upstanding fastening elements is profile extrusion, as described, for example, in U.S. Pat. No. 4,894,060 (Nestegard). Typically, in this method, a thermoplastic resin flow stream is passed through a patterned die lip (e.g., cut by electron beam machining) to form a web with downweb ridges. The ridges are then chopped transversely along their extension at spaced intervals to form upstanding fastening elements with small separations by a cutting blade. Stretching then increases the separation between the upstanding fastening elements. However, it should be understood that "upstanding fastening elements" do not include such ridges before they are cut. Such ridges themselves are not considered to have "loop-engagement overhangs" because they cannot engage with loops before being cut and stretched. In some embodiments, mechanical fasteners according to the present disclosure are not made by profile extrusion.

[0033] In mechanical fasteners according to the present disclosure, the upstanding fastening elements, which may be made, for example, by any of the methods described above, may have a variety of cross-sectional shapes. For example, the cross-sectional shape of the posts may be polygonal, which may or may not be a regular polygon (e.g., square, rectangular, hexagonal, or pentagonal), or the cross-sectional shape of the posts may be curved (e.g., circular or elliptical). In some embodiments, the posts taper, decreasing in dimension, from the proximal end to the distal end.

[0034] Typically, the distal end of an upright fastening element has a shape different from the shape of the post. For example, the fastening element may be mushroom-shaped (e.g., a head enlarged into a circular or oval shape relative to the post), nail-shaped, or T-shaped. Upright fastening elements having these shapes are typically considered multidirectional. In some of these embodiments, the overhang extends beyond the post on at least two opposite sides of the post. The extent of the overhang on the two opposite sides may be equal or unequal. In some of these embodiments, the upright fastening element is mushroom-shaped (e.g., a head enlarged into a circular or oval shape relative to the post) or nail-shaped. In upright fastening elements having a cap, the cap has at least a partial overhang in all directions, but the amount of overhang need not be the same in all directions.

[0035] The overhangs in the upright fastening elements disclosed herein are typically considered to be loop-engaging. As used herein, the term "loop-engaging" refers to the ability of the upright fastening element to be mechanically attached to the loop material. The loop-engaging ability of the hook element can be measured and defined using standard woven, nonwoven, or knitted materials. In the region of the post having the loop-engaging overhang, the distal end combined with the loop material generally has at least one of higher peel strength, dynamic shear strength, and dynamic friction than the region of the post without the loop-engaging overhang.

[0036] The thermoplastic backing may have a substantially uniform cross-section, or the thermoplastic backing may have additional structure beyond that provided by the upstanding fastening elements, which may be imparted, for example, by at least one of the forming rolls described above.

[0037] In some embodiments, the nip gap between the two rolls or between the die face and the roll in the extrusion and casting processes described above provides a thermoplastic backing thickness in the range of 20 μm to 80 μm in the mechanical fasteners disclosed herein. An endless metal or polymer belt, or a polymer-coated metal belt, can be useful to provide uniform pressure in the nip.

[0038] In some embodiments, mechanical fasteners according to the present disclosure are made by a method including stretching an initially formed thermoplastic backing to achieve a backing thickness in the range of 20 μm to 80 μm. Stretching can occur biaxially or uniaxially across the web. Biaxial stretching refers to stretching in two different directions in the plane of the thermoplastic backing. Typically, but not necessarily, one first direction is the longitudinal direction "L" and the other second direction is the widthwise direction "W." Biaxial stretching may occur sequentially, for example, by stretching the thermoplastic backing in either the first or second direction, followed by the other of the first or second directions. Biaxial stretching may occur substantially simultaneously in both directions. Uniaxial stretching refers to stretching in only one direction in the plane of the thermoplastic backing. Typically, uniaxial stretching occurs in one of the "L" or "W" directions, although stretching in other directions is also possible.

[0039] In some embodiments, stretching increases at least one of the length ("L") or width ("W") of the thermoplastic backing by at least 1.5 times (in some embodiments, at least 2, 2.5, or 3 times). In some embodiments, stretching increases both the length ("L") or width ("W") of the thermoplastic backing by at least 1.5 times (in some embodiments, at least 2, 2.5, or 3 times). In some embodiments, stretching increases at least one of the length ("L") or width ("W") of the thermoplastic backing by up to 7 times or 5 times. In some embodiments, stretching increases both the length ("L") or width ("W") of the thermoplastic backing by up to 7 times or 5 times. Some stretching may be performed to achieve a desired basis weight for the mechanical fastener.

[0040] In some embodiments, stretching is carried out to at least the natural stretch ratio. When a thermoplastic film (e.g., a thermoplastic backing described herein) is stretched uniaxially or biaxially at a temperature below the melting point of the thermoplastic material, particularly below the linear stretch temperature of the film, the thermoplastic film may stretch nonuniformly, forming a distinct boundary between stretched and unstretched portions. This reduction is referred to as necking or linear stretching. However, when stretched to a sufficiently high degree, substantially the entire thermoplastic backing is uniformly stretched. The stretch ratio at which this occurs is referred to as the "natural stretch ratio" or "natural stretch factor." The natural stretch ratio can be defined, for example, as the stretch ratio at which the relative standard deviation of local stretch ratios measured at various locations on the thermoplastic backing is less than about 15 percent. Stretching beyond the natural stretch ratio tends to result in highly uniform properties or characteristics such as thickness, tensile strength, and modulus. For any given thermoplastic backing and stretching conditions, the natural stretch ratio is determined by factors such as the composition of the thermoplastic resin forming the thermoplastic backing, the morphology of the formed thermoplastic backing due to the quenching conditions on the tool roll, and the temperature and speed of stretching. Furthermore, for biaxially stretched thermoplastic backings, the natural stretch ratio in one direction is affected by the stretching conditions in the other direction, including the final stretch ratio. Thus, the natural stretch ratio in one direction can be said to be subject to a fixed stretch ratio in the other direction, or it can be said to be a pair of stretch ratios (one in a first direction and one in a second direction) that result in a natural stretch ratio. The term "stretch ratio" refers to the ratio of the linear dimension of a given portion of the thermoplastic backing after stretching to the linear dimension of the same portion of the thermoplastic backing before stretching.

[0041] In some embodiments, the stretching is performed to an extent that is less than the natural stretch ratio of the thermoplastic backing, ie, the thermoplastic backing is stretched in one direction (e.g., the machine direction) by a ratio in the range of 1.5 to 4.

[0042] When the thermoplastic backing is a web of indefinite length, for example, uniaxial stretching in the machine direction can be achieved by propelling the thermoplastic web over a roll at an increasing speed. The most common stretching method, which allows for uniaxial, continuous biaxial, and simultaneous biaxial stretching of thermoplastic webs, uses a flat film tenter apparatus. Such an apparatus uses multiple clips, grippers, or other film edge gripping means along opposite edges of the thermoplastic web to grip the thermoplastic web so that uniaxial, continuous biaxial, or simultaneous biaxial stretching is achieved in the desired direction by propelling the gripping means at different speeds along diverging rails. Increasing clip speed in the machine direction generally results in machine direction stretching. Means such as diverging rails generally result in transverse direction stretching. Uniaxial and biaxial stretching can be accomplished by the methods and apparatus disclosed, for example, in U.S. Pat. No. 7,897,078 (Petersen et al.) and the references cited therein. Flat film tenter stretching equipment is commercially available, for example, from Bruckner Maschinenbau GmbH (Siegsdorf, Germany).

[0043] In some embodiments, the stretching is performed at an elevated temperature. This may allow the thermoplastic backing to be more flexible for stretching. Heating may be provided, for example, by infrared radiation, hot air treatment, or by performing the stretching in a heated chamber. In some embodiments, heat is applied only to the second surface of the thermoplastic backing (i.e., the surface opposite the first surface and from which the upright fastening elements protrude) to minimize any damage to the upright fastening elements that may occur due to heating. For example, in these embodiments, only the roller in contact with the second surface of the thermoplastic backing is heated.

[0044] The initial thickness of the thermoplastic backing (i.e., before stretching) can be up to about 250 μm or 150 μm and / or at least about 50 μm, 75 μm, or 100 μm, depending on the desired stretch ratio of the backing and the stretched thickness of the post. In some embodiments, the initial thickness of the thermoplastic backing ranges from 50 μm to about 225 μm, from about 75 μm to about 200 μm, or from about 75 μm to about 150 μm. After stretching, the thickness of the thermoplastic backing is reduced such that the ratio of the thickness of the thermoplastic backing before stretching to the thickness of the thermoplastic backing after stretching is, for example, 1.5:1 to 5:1, and in some embodiments, 1.5:1 to 3:1. The thickness of the thermoplastic backing after stretching is typically in the range of 20 μm to 80 μm, and in some embodiments, can be in the range of 20 μm to 70 μm or 30 μm to 70 μm.

[0045] In embodiments in which a mechanical fastener according to the present disclosure is stretched, the thermoplastic backing has stretch-induced molecular orientation in at least one direction. Whether a thermoplastic backing has stretch-induced molecular orientation is determined by standard spectroscopic analysis of the birefringence of the oriented thermoplastic polymer forming the backing. Mechanical fasteners with stretch-induced molecular orientation are also said to be birefringent, meaning that the thermoplastic backing has different effective refractive indices in different directions. In this application, whether a thermoplastic backing has stretch-induced molecular orientation is measured using a flame-retardant imaging system available from Lot-Oriel GmbH & Co. (Darmstadt, Germany) under the trade name "LC-PolScope" with a microscope available from Leica Microsystems GmbH (Wetzlar, Germany) under the trade name "DMRXE" and a CCD color camera available from QImaging (Surrey, BC, Canada) under the trade name "RETIGA EXi FAST 1394." The microscope is equipped with a 546.5 nm interference filter obtained from Cambridge Research & Instrumentation, Inc. (Hopkinton, Mass.) and a 10x / 0.25 objective.

[0046] Advantageously, various densities of upstanding fastening elements may be useful in mechanical fasteners according to the present disclosure. In some embodiments of mechanical fasteners according to the present disclosure, the upstanding fastening elements have a density of at least 248 per square centimeter (cm 2 ) (1600 per square inch, in 2 ) and up to about 1500 / cm 2 (10000 / in 2 ), 1240 / cm 2 (8000 / in 2 ), or 852 / cm 2 (5500 / in 2 In some embodiments, the density of the upright fastening elements is 271 / cm 2 (1750 / in 2 ) ~ approx. 852 / cm 2 (5500 / in 2 ) or 248 / cm 2 (1600 / in 2 )~542 / cm 2 (3500 / in 2 In some embodiments, the density of the upstanding fastening elements may range from about 465 / cm 2 (3000 / in 2 The spacing of the upright fastening elements does not have to be uniform.

[0047] In embodiments in which the thermoplastic backing is stretched, the initial density of the upstanding fastening elements prior to stretching is at least 542 / cm 2 (3500 / in 2 ), 787 / cm 2 (5000 / in 2 ), or 852 / cm 2 (5500 / in 2 ) up to 1550 / cm 2 (10000 / in 2 ) The stretching can then be carried out at an optimum stretch ratio to achieve the desired density in the upstanding fastening elements.

[0048] The density of the upstanding fastening elements and the cap area can be used to measure the cap relative density in the mechanical elements disclosed herein. The cap relative density, also referred to as the aspect ratio, can affect the feel of the mechanical fastener when the upstanding fastening elements come into contact with human skin. The collective cap area of ​​the mechanical fastener divided by the total area of ​​the mechanical fastener is a measure of the cap relative density. In some embodiments of the mechanical fasteners disclosed herein, the cap relative density ranges from 10 percent to 40 percent, and in some embodiments, from 10 percent to 30 percent, from 15 percent to 30 percent, or from 10 percent to 24 percent.

[0049] In any of the embodiments of the mechanical fasteners according to the present disclosure, the thermoplastic backing may be in roll form, from which, for example, a mechanical fastener patch may be cut to dimensions appropriate for the desired application. In this application, the thermoplastic backing may also be a patch cut to the desired dimensions. In some of these embodiments, the second surface of the thermoplastic backing (i.e., the surface opposite the first surface from which the upstanding fastening elements protrude) may be coated with an adhesive (e.g., a pressure-sensitive adhesive). In such embodiments, when the thermoplastic backing is in roll form, a release liner may be applied to the exposed adhesive.

[0050] In some embodiments of the mechanical fasteners disclosed herein, the thermoplastic backing is not bonded to the support material, at least when it is initially formed. In other embodiments, the second surface of the thermoplastic backing (i.e., the surface opposite the first surface from which the upstanding fastening elements protrude) is bonded to the support material. The thermoplastic backing may be bonded to the support material, for example, by lamination (e.g., extrusion lamination), adhesion (e.g., pressure-sensitive adhesive), or other bonding methods (e.g., ultrasonic bonding, compression bonding, or surface bonding). The thermoplastic backing may be bonded to the support material during formation of the thermoplastic backing with the upstanding posts. The resulting article may be a fastening laminate, for example, a fastening tab bonded to the backsheet of an absorbent article, useful for joining the front and back waist regions of the absorbent article.

[0051] In some embodiments, the support material that can be bonded to the second surface of the thermoplastic backing can be continuous (i.e., without any through holes) or discontinuous (e.g., containing perforations or holes therethrough). The support material can comprise a variety of suitable materials, including woven webs, nonwoven webs (e.g., spunbond webs, spunlace webs, aeolian webs, meltblown webs, and bonded carded webs), textiles, plastic films (e.g., single-layer or multilayer films, coextruded films, or films containing foam layers), and combinations thereof. In some embodiments, the support material is a fibrous material (e.g., woven, nonwoven, or knitted material). When referring to a support material or web, the term "nonwoven" means having a structure of individual fibers or threads that are entangled, but not identifiably entangled, as in knitted fabrics. Nonwoven fabrics or webs can be formed from a variety of processes, such as meltblown processes, spunbond processes, spunlace processes, and bonded carded web processes. In some embodiments, the support material comprises a multi-layer nonwoven material, e.g., having at least one meltblown nonwoven layer and at least one spunbond nonwoven layer, or any other suitable combination of nonwoven materials. For example, the support material may be a spunbond-meltbond-spunbond, spunbond-spunbond, or spunbond-spunbond-spunbond multi-layer material. Alternatively, the support material may be a composite web comprising a nonwoven layer and a high-density film layer.

[0052] Fibrous materials that provide useful support materials may be made from natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., thermoplastic fibers), or a combination of natural and synthetic fibers. Exemplary materials for forming thermoplastic fibers include polyolefins (e.g., polyethylene, polypropylene, polybutylene, ethylene copolymers, propylene copolymers, butylene copolymers, and copolymers and blends of these polymers), polyesters, and polyamides. The fibers may also be multicomponent fibers, for example, having a core of one thermoplastic material and a sheath of another thermoplastic material.

[0053] One or more regions of the support material may comprise one or more elastically extensible materials that stretch in at least one direction when a force is applied and return to approximately their original dimensions after the force is removed. The term "elastic" refers to any material that exhibits recovery from stretch or deformation. Similarly, "non-elastic" materials that do not exhibit recovery from stretch or deformation may also be useful as support materials.

[0054] Mechanical fasteners according to the present disclosure are useful components in fastening systems that include a mechanical fastener according to any of the above-described embodiments and a loop material. While mechanical fasteners according to the present disclosure are useful with a variety of different loop materials, in some embodiments, the loop material is a low-loft loop material, which is desirable for use in fastening systems due to its low cost and low material usage. Examples of low-loft materials include, for example, nonwoven materials made from any of the materials described above as the support material. In some embodiments, the loop material has a fiber basis weight ranging from 10 grams per square meter (gsm) to 30 gsm. The fiber weight is the basis weight of the fibers only in the loop material (e.g., removed from any backing material). In some embodiments, the loop material has a basis weight ranging from 10 gsm to 20 gsm or from 15 gsm to 20 gsm. In some embodiments, the loop material has a fiber diameter ranging from 15 micrometers to 25.4 micrometers. The loop material can have a loop height of up to 500 μm and a loop width of up to 2500 μm. In some embodiments, the loop material has a fiber basis weight ranging from 20 grams per square meter to 30 grams per square meter, and the mechanical fasteners engage the loop material with a shear force of at least 2000 grams force, although in other embodiments, the mechanical fasteners may be similarly useful with loop materials having fiber basis weights ranging from 30 gsm to 50 gsm.

[0055] The fastening laminate, which can be formed after joining the thermoplastic backing to the support material, can be useful, for example, in disposable absorbent articles. Some examples of absorbent articles have at least a front waist region, a back waist region, and a longitudinal centerline that bisects the front and back waist regions, and at least one of the front or back waist regions includes a structured surface according to the methods disclosed herein. The fastening laminate can be in the form of a fastening tab that is attached to at least one of the front or back waist regions and extends outward from at least one of the left or right longitudinal edges of the absorbent article. In other embodiments, the fastening laminate can be an integral ear portion of the absorbent article.

[0056] FIG. 2 is a schematic perspective view of one embodiment of an absorbent article according to the present disclosure. The absorbent article is a diaper 60 having a substantially hourglass shape. The diaper includes an absorbent core 63 between a liquid-permeable topsheet 61 that contacts the wearer's skin and an outwardly facing liquid-impermeable backsheet 62. The diaper 60 has a rear waist region 65 with two fastening tabs 70 located at two longitudinal edges 64a, 64b of the diaper 60. The diaper 60 may include elastic material 69 along at least a portion of the longitudinal side edges 64a, 64b to provide leg cuffs. The longitudinal direction "L" of an absorbent article (e.g., the diaper 60) refers to the direction in which the article extends from the front to the back of the user. Thus, the longitudinal direction refers to the length of the absorbent article between the rear waist region 65 and the front waist region 66. The lateral direction of an absorbent article (e.g., diaper 60) refers to the direction in which the article extends from the user's left side to their right side (or vice versa) (i.e., in the embodiment of FIG. 2, from longitudinal edge 64a to longitudinal edge 64b).

[0057] In FIG. 2 , the fastening tab 70 is secured to the rear waist region 65 by its manufacturer end 70 a. The user's end 70 b of the fastening tab includes a mechanical fastener 80 according to the present disclosure. In some embodiments, when the diaper 60 is applied to a wearer's body, the user's end 70 b of the fastening tab 70 can be attached to a target area 68 including a fibrous material 72 that can be disposed on the backsheet 62 in the front waist region 66. For example, examples of loop tape that can be applied to the target area 68 to provide exposed fibrous material 72 are disclosed in U.S. Pat. No. 5,389,416 (Mody et al.), EP Pat. No. 0,341,993 (Gorman et al.), and EP Pat. No. 0,539,504 (Becker et al.). In other embodiments, the backsheet 62 includes a woven or nonwoven fibrous layer that can interact with the user's end 70 b of the fastening tab 70, which includes a mechanical fastener as disclosed herein. Examples of such backsheets 62 are disclosed, for example, in U.S. Patent Nos. 6,190,758 (Stopper) and 6,075,179 (McCormack et al.), and are described in the Examples below. Advantageously, having a level engageable with a mechanical fastener according to the present disclosure allows for good fastening between the hook strips 70 and the backsheet 62, eliminating the target area 68. Thus, in some embodiments, the disposable absorbent articles disclosed herein do not include a target loop landing area. In some embodiments, at least one of the front waist region or the back waist region includes a loop material having a fiber basis weight in the range of 10 gsm to 20 gsm.

[0058] While the embodiment shown in Figure 2 is an absorbent article with attached fastening tabs, it is envisioned that the mechanical fasteners disclosed herein are equally useful for absorbent articles having larger hook areas. For example, the ears of the absorbent article could themselves include the mechanical fasteners disclosed herein, or the absorbent article could have two target zones of loop material along the longitudinal edges of the backsheet in one waist region and two hook strips extending along the longitudinal edges of the absorbent article in the opposite waist region.

[0059] The fastening laminates according to the present disclosure are also useful as fastening tabs in pant diapers, such as those described in U.S. Pat. No. 5,531,732 (Wood). In some embodiments, the absorbent article according to the present disclosure is a disposable pant diaper having a fibrous outer sheath or backsheet that can engage with the upright fastening elements in the fastening tabs disclosed herein. The fastening tabs can be located in the seam or side panel portions of the pant diaper so that the free ends of the fastening tabs can engage with the fibrous outer sheath or backsheet. The free ends of the fastening tabs are useful for adjusting the circumferential fit or size (i.e., waist fit or size) of the pant diaper, for example, by gathering the side panel portions. In some embodiments, the side panel portions may not include any integrally bonded absorbent core structure. In some embodiments, the pant diaper has at least one perforation line extending from the waist opening to one of the leg openings. Generally, the perforations are located near the side seams, toward the front of the diaper, and can be parallel or non-parallel to the side seams. In some embodiments, the pant-type diaper has a pair of perforation lines, one on each side of the diaper. The perforation lines can be broken either before the diaper is positioned around the user's waist or while the user is wearing the diaper. The fastening tab free ends can then be used to refasten the diaper to fit snugly around the user's waist. The fastening tab free ends can also be useful as disposal means, for example, when the pant-type diaper is removed from the wearer (e.g., by breaking the side panels or perforation lines). The fastening tabs typically remain in the side panel portions. The diaper is then rolled into a compact shape for disposal, and the fastening tabs can be used to maintain the diaper in the rolled shape.

[0060] In some embodiments, fastening tabs according to the present disclosure can be applied to pant-type diapers during the manufacturing process using a laminate in which separate strips of mechanical fasteners disclosed herein are laminated to a nonwoven web using any of the methods described above. In some embodiments, two strips of mechanical fasteners can be positioned on the nonwoven web, with the nonwoven extending beyond the mechanical fastening strips on both sides, such that the exposed nonwoven is separated into first and second sides and a center by the mechanical fastening strips of the laminate. The laminate can be in roll form with the separate mechanical fastening strips extending longitudinally. In an embodiment useful in the manufacturing process for pant-type diapers, the laminate can be cut transversely to create fastening tabs of the desired width and aligned to connect two diapers together on the diaper chassis web. The laminate can then be simultaneously or nearly simultaneously cut down to the center of the exposed central portion of the nonwoven, and the two connected diapers can be separated so that one half of the laminate is applied to one diaper and the other half is applied to the other diaper. The joining of the side seams of the diaper and the joining of the fastening tabs to the side seams can then be performed simultaneously, if desired. In these embodiments, each of the first and second sides of the exposed nonwoven can advantageously serve as fingers in the left and right fastening tabs of two different pant-type diapers.

[0061] Fastening laminates including the mechanical fasteners disclosed herein may also be useful in absorbent articles such as sanitary napkins. Sanitary napkins typically include a backsheet intended to be placed adjacent to a wearer's undergarments. The backsheet may include a thermoplastic backing having spaced apart, upstanding capped posts that mechanically engage with the capped posts to securely attach the sanitary napkin to the undergarment. The backsheet may be formed with the upstanding capped posts. In other embodiments, the mechanical fasteners may be in the form of strips or patches that are attached to the backsheet using adhesive or other bonding mechanisms.

[0062] In other embodiments, mechanical fasteners according to the present disclosure may also be useful in absorbent pads having, for example, at least one topsheet, an absorbent core, and a backsheet including a mechanical fastener. The backsheet may be formed with upstanding capped posts. In other embodiments, the mechanical fasteners may be in the form of strips or patches attached to the backsheet using adhesive or other attachment mechanisms. The absorbent pad may be useful in adult incontinence articles, for example, in the form of an open diaper or a pant-type diaper having the general shape shown in FIG. 2. In these embodiments, the mechanical fasteners are useful for attaching the absorbent pad to the topsheet of the adult incontinence article, and an appropriate shear force is useful for holding the pad in place, while the peel strength of the mechanical fasteners should be low enough to allow the pad to be easily removed by the user or caregiver. In other embodiments, absorbent pads including mechanical fasteners according to the present disclosure may be attached directly to the user's garment for the purpose of absorbing urine. It has been traditionally thought that increasing hook density and hook height is useful for increasing engagement with loop materials (e.g., WO 2006 / 101844 (Petersen et al.)), and that such changes tend to increase the basis weight of the mechanical engagement members. Mechanical fasteners according to the present disclosure have now been found to provide surprisingly high shear and peel performance for low loft loop materials, despite their low basis weight. As shown in the examples below, mechanical fasteners according to the present disclosure provide engagement with loop materials that is equal to or exceeds that of commercially available hook fasteners designed to engage low loft loop materials.

[0063] The low basis weight of the mechanical fasteners disclosed herein provides the advantage of flexibility of the fasteners, which reduces the tendency of the mechanical fasteners to disengage when the mechanical fastener members are twisted. Because the mechanical fasteners disclosed herein have a low basis weight and typically low viscosity, they are typically softer (e.g., may feel cloth-like) and less irritating to a user's skin (e.g., when the mechanical fastener is on an absorbent article). The mechanical fasteners disclosed herein are less expensive to manufacture because they require less material.

[0064] A comparison of the flexibility of mechanical fasteners according to the present disclosure and examples of mechanical fasteners having higher basis weights is shown below in Example 29 and Illustrative Example 6. When evaluated in terms of loop flexibility, the mechanical fasteners according to the present disclosure were significantly lower than the mechanical fasteners with thicker base films and taller capped posts.

[0065] Surprisingly, mechanical fasteners according to some embodiments of the present disclosure exhibit improved shear performance compared to mechanical fasteners of the same size but with thicker thermoplastic backings and higher densities of fastening elements. For example, a comparison of exemplary Example 4 with Example 3, and an comparison of exemplary Example 5 with Example 4 in the examples below show increased thermoplastic backing elongation, reduced thickness, and unexpectedly improved shear performance, even though the density of the upstanding elements is reduced by half.

[0066] Mechanical fasteners according to the present disclosure provide shear strength useful in securing pads for use in adult incontinence. As shown in the following examples, e.g., Examples 20-28, as cap diameter dimensions and cap overhang decrease, the peel strength of the nonwoven to the topsheet material also tends to decrease. In some embodiments, in mechanical fasteners useful for securing pads, the thermoplastic backing has a thickness ranging from 40 μm to 75 μm, and the upstanding fastening elements have a height ranging from 50 μm to 300 μm (in some embodiments, 100 μm to 300 μm or 150 μm to 300 μm), a cap diameter ranging from 190 μm to 320 μm (in some embodiments, 200 μm to 300 μm), and a cap overhang ranging from 5 μm to 65 μm. In open-type adult incontinence articles, the cap overhang may range from 5 μm to 30 μm (in some embodiments, 10 μm to 30 μm or 15 μm to 25 μm), and in pant-type adult incontinence articles, the cap overhang may range from 30 μm to 65 μm (in some embodiments, 30 μm to 55 μm or 30 μm to 50 μm). In adult incontinence applications, open-type diapers may be applied by a caregiver to a user who may be bedridden. In these applications, the peel strength of the mechanical fasteners holding the absorbent pad on the diaper topsheet may be lower than that required in pant-type diapers. Thus, a lower cap overhang, for example, as in Example 23 below, may be useful. Pant-type diapers can be donned and doffed by users who are typically more active than users of open-type diapers. This increased action allows for a higher peel strength between the absorbent pad and the diaper, and therefore a larger cap overhang may be useful in pant diapers.

[0067] Some embodiments of the present disclosure In a first embodiment, the present disclosure provides a method for manufacturing a semiconductor device comprising: a thermoplastic backing; and a plurality of upstanding fastening elements having a post with a proximal end attached to the thermoplastic backing and a distal end including a cap having an area greater than a cross-sectional area of ​​the post; The mechanical fastener is provided wherein the plurality of upstanding fastening elements have a height of up to 300 micrometers and the basis weight of the mechanical fastener is in the range of 25 grams per square meter to 75 grams per square meter.

[0068] In a second embodiment, the present disclosure provides a mechanical fastener according to the first embodiment, wherein the cap extends beyond the post on at least two opposing sides of the post.

[0069] In a third embodiment, the present disclosure provides a mechanical fastener according to the first or second embodiment, wherein the height of the upstanding fastening elements is at least 100 micrometers.

[0070] In a fourth embodiment, the present disclosure provides a mechanical fastener according to any of the first to third embodiments, wherein the thermoplastic backing has a thickness in the range of 20 micrometers to 80 micrometers.

[0071] In a fifth embodiment, the present disclosure provides a mechanical fastener according to any of the first to fourth embodiments, wherein the cap extends beyond the post by an overhang distance, the overhang distance being in the range of 5 micrometers to 85 micrometers.

[0072] In a sixth embodiment, the present disclosure provides the mechanical fastener according to any one of the first to fifth embodiments, wherein the quotient of the overhang distance divided by the height is at most 0.6.

[0073] In a seventh embodiment, the present disclosure provides a mechanical fastener according to any of the first to sixth embodiments, wherein at least a portion of the post decreases in dimension from the proximal end to the distal end.

[0074] In an eighth embodiment, the present disclosure provides a mechanical fastener according to any of the first to seventh embodiments, wherein at least a portion of the overhang is folded against the thermoplastic backing.

[0075] In a ninth embodiment, the present disclosure provides a mechanical fastener according to any of the first to eighth embodiments, wherein the upstanding fastening elements are present on the thermoplastic backing at a density ranging from 248 per square centimeter to 542 per square centimeter.

[0076] In a tenth embodiment, the present disclosure provides a fastening device according to any of the first to ninth embodiments, wherein the thermoplastic backing has stretch-induced molecular orientation in at least one direction.

[0077] In an eleventh embodiment, the present disclosure provides a fastening device according to any of the first to tenth embodiments, wherein the upstanding fastening elements have a height of up to 285 micrometers.

[0078] In a twelfth embodiment, the present disclosure provides a fastening device including the mechanical fastener according to any of the first to eleventh embodiments and a loop material that engages with the mechanical fastener.

[0079] In a thirteenth embodiment, the present disclosure provides a fastening device according to the twelfth embodiment, wherein the loop material has a fiber basis weight in the range of 10 grams per square meter to 30 grams per square meter.

[0080] In a fourteenth embodiment, the present disclosure provides a fastening device according to the twelfth embodiment, wherein the loop material has a fiber basis weight in the range of 20 grams per square meter to 30 grams per square meter, and the mechanical fastener engages the loop material with a shear strength of at least 2000 grams force.

[0081] In a fifteenth embodiment, the present disclosure provides a fastening device according to any of the twelfth to fourteenth embodiments, wherein the loop material has a fiber diameter in the range of 15 micrometers to 25 micrometers.

[0082] In a sixteenth embodiment, the present disclosure provides an absorbent article including the mechanical fastener according to any one of the first to eleventh embodiments.

[0083] In a seventeenth embodiment, the present disclosure provides an absorbent article as described in the sixteenth embodiment, further comprising a front waist region and a back waist region, wherein at least one of the front waist region or the back waist region comprises a mechanical fastener.

[0084] In an eighteenth embodiment, the present disclosure provides an absorbent article as described in the seventeenth embodiment, wherein the front waist region comprises a loop material having a fiber basis weight in the range of 10 grams per square meter to 20 grams per square meter.

[0085] In a 19th embodiment, the present disclosure provides an absorbent article as described in the 16th embodiment, wherein the absorbent article is an absorbent pad having at least one topsheet, an absorbent core, and a backsheet, and the backsheet includes a mechanical fastener as described in any of the 1st to 11th embodiments.

[0086] In a twentieth embodiment, the present disclosure provides an absorbent article according to the nineteenth embodiment, wherein the absorbent pad is attached to a topsheet of a diaper or attached to a garment.

[0087] In a twenty-first embodiment, the present disclosure provides an absorbent article according to the nineteenth or twentieth embodiment, wherein the thermoplastic backing has a thickness in the range of 40 micrometers to 75 micrometers, and the upstanding fastening elements have a height in the range of 150 micrometers to 300 micrometers, a cap diameter in the range of 190 micrometers to 320 micrometers, and a cap overhang in the range of 5 micrometers to 65 micrometers.

[0088] In a 22nd embodiment, the present disclosure provides an absorbent article according to the 16th embodiment, wherein the absorbent article is a pant diaper and the mechanical fastener is disposed on a tab on a seam or side panel portion of the pant diaper.

[0089] In a twenty-third embodiment, the present disclosure provides a mechanical fastener according to any one of the first to eleventh embodiments, wherein the upstanding fastening elements do not have the following combination of overall dimensions: cap thickness of 48 micrometers, cap diameter in the horizontal direction of 260 micrometers, cap diameter in the vertical direction of 196 micrometers, backing thickness of 50 micrometers, height of 169 micrometers, post diameter at the base of 157 micrometers, and post diameter below the cap of 145 micrometers.

[0090] In order that this disclosure might be more fully understood, the following examples are set forth. It should be understood that these examples are for illustrative purposes only and are not to be construed as limiting this disclosure in any manner. [Example]

[0091] Mechanical Fastening Strips Examples 1-19, Comparative Example 1 (Part No. CHK-01324 available from 3M Company, St. Paul, MN), and Illustrative Examples 1-5 were prepared from an ethylene-propylene copolymer available from Dow Chemical Company, Midland, MI under the trade designation "C700-35N" using the method described in U.S. Pat. No. 5,845,375 (Miller et al.). The mechanical fastening strips of Examples 1-19 were arranged in either a square or staggered pattern with densities ranging from 271 to 542 upstanding fastening elements per square centimeter. 2 A mechanical fastening strip having a density of 542 / cm 2The strips were prepared by machine stretching a strip having a density of 1000 kJ / cm2 at a stretch ratio of 2:1 in the machine direction. Exemplary Examples 4 and 5 were stretched in the machine direction at a stretch ratio of 2:1 to prepare Examples 3 and 4, respectively. The posts were conical or rectangular. Upright fastening elements with "grooved caps" were prepared by the process described in U.S. Pat. No. 5,868,987 (Kampfer et al.). The term "ridge" refers to a reformed cap where the overhanging portion of the distal cap extending beyond the post is depressed toward the backing (the reforming process described in U.S. Pat. No. 6,132,660 (Kampfer)).

[0092] The mechanical fastening strip of Comparative Example 1 can also be obtained by removing the hook tabs from the commercially available adult diaper "TENA ULTRA" (SCA Corporation, Stockholm, Sweden). The hook strip of Comparative Example 2 was obtained by removing the hook tabs from the commercially available adult diaper "PREVAIL BREEZERS" (First Quality Corporation, Great Neck, NY).

[0093] In Table 1, the density of upstanding fastening elements (number per square centimeter), cap shape (round or oval), cap shape (raised or non-raised), and cap appearance (grooved or flat) were recorded for the mechanical fastening strips of Examples 1-19, Comparative Examples (Comp. Ex.) 1-2, and Illustrative Examples (Illustrative Ex.) 1-5.

[0094] [Table 1]

[0095] In Table 2, the cap thickness, cross direction (CD) cap diameter, and machine direction (MD) cap diameter measurements for the mechanical fastening strips of Examples 1-19, Comparative Examples 1-2, and Illustrative Examples 1-5 are recorded.

[0096] [Table 2]

[0097] In Table 3, for the mechanical fastening strips of Examples 1-19, Comparative Examples 1-2, and Illustrative Examples 1-5, the backing thickness, the post height before capping, the post height with the cap formed, the post diameter measured at the bottom (distance "w" in FIG. 1), the post diameter measured just below the cap (distance "w" in FIG. 1), and the post diameter measured just below the cap (distance "w" in FIG. 1). 1 "), and basis weight measurements were recorded. The height of the capped pillar is defined as the measured distance from the top surface of the backing to the tip of the cap (distance "h" in Figure 1).

[0098] [Table 3]

[0099] The calculated cap overhang, bending index (BI), and cap relative density were recorded for Examples 1-19, Comparative Examples 1-2, and Illustrative Comparative Examples 1-5 in Table 4. Cap overhang was calculated using the following equation: Cap overhang (μm) = (cap diameter - diameter of pillar under cap) / 2

[0100] The bending index (BI) was calculated using the following equation: BI = Cap overhang / Capped column height

[0101] In this equation, the cap diameter was measured at the longest dimension and the post diameter was measured just below the cap.

[0102] The cap relative density was calculated using the following equation: Cap relative density = Cap assembly area / Mechanical fastener area

[0103] [Table 4]

[0104] All measurements in Tables 1 to 5 were recorded using a Keyence VHX-600E microscope (Keyence Corporation, Osaka, Japan) equipped with a VH-Z20R lens and a data acquisition software package at magnifications ranging from 20X to 200X.

[0105] Test method and test results Shear strength and peel strength tests were used to measure the release performance characteristics of the mechanical fastening strips of Examples 1-19, Comparative Examples 1-2, and Illustrative Examples 1-5. All tests were conducted under constant temperature (23°C ± 2°C) and relative humidity (50% ± 5%). All materials and equipment were equilibrated at these conditions for a minimum of 24 hours prior to testing. A constant-rate extension tensile testing instrument (Series 4200, 4500, or 5500 available from Instron Engineering Corporation, Canton, MA) equipped with a computer for data recording and the required load range was used. For all tests, the instrument crosshead speed was set at 305 mm / min, and the peel distance was at least 32 mm.

[0106] Three different polypropylene nonwoven loop samples were used to evaluate the mechanical fastening strips of Examples 1-19, Comparative Examples 1-2, and Illustrative Examples 1-5. Sample 1 was a low-loft nonwoven loop material obtained from the backsheet of an adult diaper commercially available from First Quality Corporation (Great Neck, NY) under the trade name "PREVAIL BREEZERS." Sample 2 was a low-loft nonwoven loop material obtained from the backsheet of an adult diaper commercially available from SCA Corporation (Stockholm, Sweden) under the trade name "TENA ULTRA." Sample 3 was a low-loft nonwoven loop material obtained from the backsheet of an adult diaper commercially available from Medline Industries (Mundelein, IL) under the trade name "RESTORE." In all tests, the outer surface (garment-facing side) of the diaper was used to engage the mechanical fastener sample. In Table 5, measurements of fiber diameter, loop height (loft), loop width, and fiber basis weight for nonwoven loop samples 1-3 were recorded.

[0107] [Table 5]

[0108] Test Method 1 measured the shear strength of fasteners prepared from the mechanical fastening strips of Examples 1-19, Comparative Examples 1-2, and Illustrative Examples 1-5, comprising the nonwoven loop materials of Samples 1-3, in accordance with ASTM D5169-98. Finished mechanical fastener specimens were prepared by attaching a 12.7 mm cross direction (CD) by 25.4 mm machine direction (MD) strip to a 76 mm by 25.4 mm leader of 898 filament tape (available from 3M Company, St. Paul, MN). An additional 76 mm by 25.4 mm strip of filament tape was used to cover the exposed adhesive (leaving none remaining on the first strip).

[0109] The finished nonwoven loop material was cut to form 76mm wide by 30mm long strips backed with 76mm x 30mm 898 filament tape. An example mechanical fastener sample was gently placed fastening element-side down on the corresponding loop surface and clamped with a 5 kilogram handheld roller for five cycles (five forward and five backward passes). The material was positioned so that shear strength measurements could be taken in the example sample's cross-direction and the loop's cross-direction. With some slack, the example sample leader was attached to the upper jaw of the Instron instrument, and the loop sample was attached to the lower jaw.

[0110] The initial jaw separation (gauge length) was set at 76 mm. The instrument was started and the upper jaw was moved until the example specimen was completely released from the loop sample. Measured at maximum load in grams-force (gf) (Newtons). Ten replicates were performed, each using new material, and data was collected from the minimum value, averaged, and the average data was recorded in Table 6.

[0111] [Table 6]

[0112] Test Method 2 measured the force required to peel example mechanical fasteners from loop materials at a 135-degree peel angle. The test jig was set at 135 degrees (fixed) on an Instron tensile tester. Completed mechanical fasteners (selected from Examples 1-19, Comparative Examples 1-2, and Illustrative Comparative Examples 1-5) were prepared as 19 mm crosswise x 25.4 mm longitudinal strips using fastening tape as the backing. The completed example samples were attached to one end of a 25.4 mm x 203 mm paper leader. The completed nonwoven loop materials (selected from Samples 1-3) were attached to a 51 mm x 127 mm x 1.6 mm steel plate with double-sided tape. The example samples were gently placed with the fastening element facing down on the corresponding loop side and secured in place with a 2-kilogram handheld roller for one cycle (one cycle = one forward and one backward pass). The materials were positioned so that peeling occurred across the example sample and across the loop.

[0113] [Table 7]

[0114] With some slack, the plate was mounted in a 135-degree fixture in the Instron tool and a paper lead was attached to the upper jaw of the tool. The initial jaw separation (gauge length) was set to at least 203 mm. The tool was started and measured at the maximum load in grams-force (gf) (Newtons). Ten replicates were performed, each using new material, and the data was collected from the minimum value, averaged, and the average data recorded in Table 7 above.

[0115] The mechanical fastening strips of Examples 20-28 were prepared according to the methods described in Examples 1-19. The backing was not stretched. In each of Examples 20-28, the density of the upstanding fastening elements was 248 / cm 2 The basis weight was 62 grams per square meter. The post height before capping was 250 micrometers. The caps of Examples 20-28 were "fluted" according to the process described in U.S. Pat. No. 5,868,987 (Kampfer et al.). In Examples 25-28, the caps were raised according to the process described in U.S. Pat. No. 6,132,660 (Kampfer). Other properties of the Examples are shown in Table 8. The measurements recorded in Table 8 were taken at 175X magnification using a Keyence VHX-1000 microscope from Keyence Corporation, equipped with a data acquisition software package, digital rangefinder, and monitor.

[0116] The mechanical fastener strips of Examples 20-28 were evaluated using a spunbonded polypropylene nonwoven fabric available from Mitsui Chemicals, Inc. (Tokyo, Japan) under the trade name "SYNTEX PS-104." For peel evaluation, a patch of mechanical fastener (25 mm machine direction (MD) and 20 mm cross direction (CD)) was attached to one end of a paper leader. The nonwoven material (50 mm machine direction and 100 mm cross direction) was attached to a metal plate using double-sided tape. A 100-gram roller was used for one cycle (one cycle = one forward and one backward pass) to press the mechanical fastener sample against the nonwoven. The materials were positioned so that the peel proceeded crosswise on the example sample and crosswise on the nonwoven. 90-degree peel was measured using an instrument available from Orientec Co., Ltd. (Fukaya, Japan) under the trade name "TENSILON RTG-1225." The initial jaw gap was 150 mm and a separation speed of 300 mm per minute was used. The evaluation was repeated six times and the average peel strength was recorded. The results are shown in Table 8 below.

[0117] For shear performance evaluation, a patch of mechanical fastener (25 mm lengthwise and 20 mm widthwise) was attached to one end of the paper leader. A nonwoven material (100 mm lengthwise and 50 mm widthwise) was attached to a metal plate using double-sided tape. A 100-gram roller was used for one cycle (one cycle = one forward and one backward pass) to press the mechanical fastener sample against the nonwoven. Measurements were taken in the widthwise direction of the example sample and the widthwise direction of the nonwoven, and the material was positioned so that the paper leader extended beyond the edges of the nonwoven and metal plate. A 10-gram weight was placed on top of the example sample, and a 100-gram weight was attached to the paper leader. If the example sample did not move within 10 seconds, an additional 100-gram weight was attached to the paper leader. After adding the weight, this process was repeated until the example sample began to move within 10 seconds. The amount of weight added before the example sample began to move was recorded. This evaluation was repeated three times and the average recorded and reported as shear force. The results are shown in Table 8 below.

[0118] Example 29 and Illustrative Example 6 were prepared according to the methods of Examples 1-19. The upright fastening elements of Example 29 had a 3000 / in 2 (465 / cm 2 The upright fastening elements of Illustrative Example 6 had a density of 900 / in 2 (140 / cm 2 The samples had a density of 100 μm, a backing thickness of 110 μm, a cap diameter of 520 μm in the cross direction, and a capped post height of 550 μm. The loop stiffness was measured for each of these samples using the following method. Specimens were prepared by cutting the mechanical fastener of Example 29 or Illustrative Example 6 into strips measuring 10 mm in the cross direction and 150 mm in the machine direction. The sample was placed on the sample holder so that the ends of the strip were flat against the sample holder, creating a loop with a circumference of 54 mm in the center of the strip. The sample was compressed to a height of 6.5 mm with a compression plate moving 3.5 mm per second. The peak force was recorded and found to be 2.5 g / mm for Example 29 and 16.5 g / mm for Illustrative Example 6.

[0119] [Table 8]

[0120] The present disclosure is susceptible to various modifications and variations without departing from its spirit and scope. Accordingly, the present disclosure is not limited to the above-described embodiments, but is controlled by the limitations set forth in the following claims and all equivalents thereof. The present disclosure may suitably be practiced in the absence of elements not specifically disclosed herein. All patents and patent applications cited above are incorporated herein by reference in their entirety.

Claims

1. A mechanical fastener comprising: a thermoplastic backing; and a plurality of upstanding fastening elements having a proximal end attached to the thermoplastic backing and a post with a distal end including a cap having an area greater than a cross-sectional area of ​​the post; the cap extends beyond the post by an overhang distance, the overhang distance being in a range of 10 micrometers to 75 micrometers, and the cap has a circular or elliptical cross-sectional shape; the thermoplastic backing has a thickness in the range of 20 micrometers to 80 micrometers; The mechanical fastener, wherein the plurality of upstanding fastening elements have a height between 40 micrometers and 203 micrometers.

2. 10. A fastening system comprising: the mechanical fastener of claim 1; and a loop material for engaging the mechanical fastener, wherein the loop material has a fiber basis weight in the range of 20 grams per square meter to 30 grams per square meter, and wherein the mechanical fastener engages the loop material with a shear strength of at least 2000 grams force.

3. 10. An absorbent article comprising the mechanical fastener of claim 1 or the fastening system of claim 2.

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