Mechanical fasteners, fastening laminates, and absorbent articles having multiple fastening elements

Abstract

The present invention relates to a mechanical fastener comprising a thermoplastic backing and a plurality of upstanding fastening elements. The plurality of upstanding fastening elements have a strut having a proximal end integrally formed with the thermoplastic backing and a distal end including spaced apart caps having a cross-sectional area greater than that of the strut. The plurality of upstanding fastening elements are present at a density ranging from 1,000 elements per square centimeter to 5,000 elements per square centimeter, and the combined cross-sectional area of ​​the spaced apart caps is between 20% and 70% of the area of ​​the mechanical fastener. The spaced apart caps are circular, elliptical, or a regular polygon having at least five sides, with no dimension exceeding 300 micrometers. The present invention also relates to laminates and absorbent articles comprising the mechanical fastener.

Description

[Background technology]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. Provisional Application No. 63 / 416,331, filed October 14, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] Mechanical fasteners, also known as hook and loop fasteners, typically comprise a hook member including multiple closely spaced upstanding projections with a loop-engageable head, and the loop member typically comprises multiple loops of woven, nonwoven, or knitted fabric. Mechanical fasteners are useful for providing releasable fastening in numerous applications. For example, mechanical fasteners are widely used to secure disposable absorbent articles to the wearer's body. In a typical configuration, for example, a hook strip or patch on a fastening tab attached to the rear waist portion of a diaper or incontinence garment is fastened to a landing zone of loop material located in the front waist region, or the hook strip or patch is fastened to a backsheet (e.g., a nonwoven backsheet) in the front waist region of the diaper or incontinence garment. Furthermore, mechanical fasteners are also useful for disposable articles such as sanitary napkins. Sanitary napkins typically include a backsheet intended to be placed adjacent to the wearer's undergarments. The backsheet includes hook fastener elements for secure attachment to the undergarment, thereby allowing for mechanical engagement with the undergarment.

[0003] Hook and loop fastening systems can have at least two engagement strength characteristics: peel strength and shear strength. Peel strength corresponds to the force required to peel one fastening member upwardly away from another fastening member. Shear strength corresponds to the force required to pull at least one fastening member away from the other in a plane parallel to the fastening members. Typically, the engagement strength of fasteners in the shear direction is higher than the engagement strength in the peel direction. While peel strength can be an important factor when fasteners are intended to separate, shear strength is the primary factor holding fasteners together during normal use.

[0004] U.S. Patent Nos. 5,679,302 (Miller et al.), 10,973,710 (Peltier et al.), and 10,165,833 (Pariseau et al.) describe mechanical fasteners in which mechanical fastening elements are present at a density of up to 1550 per square centimeter. U.S. Patent No. 8,845,943 (Hertlein et al.) describes a method for producing structured surfaces such as mechanical fasteners. U.S. Patent Nos. 5,392,498 (Goulait et al.), 7,162,780 (Martin et al.), and 7,578,812 (Datta et al.) describe skin-friendly hook fasteners. Summary of the Invention

[0005] The present disclosure provides mechanical fasteners having a relatively high pin density and a relatively high cap area percentage, as well as laminates and absorbent articles including the mechanical fasteners. The mechanical fasteners of the present disclosure have an unexpectedly soft feel, and in some embodiments, it is difficult to distinguish the difference in feel between the side with the mechanical fastener elements and the side without the fastener elements. Furthermore, despite the relatively high pin density and relatively high cap area percentage, the mechanical fasteners of the present disclosure perform at least as well as conventional mechanical fasteners in terms of engagement with loop materials as measured by shear and peel tests.

[0006] In one embodiment of the present disclosure, a mechanical fastener is provided. The mechanical fastener includes a thermoplastic backing and a plurality of upstanding fastening elements. The plurality of upstanding fastening elements have a strut having a proximal end integrally formed with the thermoplastic backing and a distal end including spaced apart caps having a cross-sectional area greater than the cross-sectional area of ​​the strut. The plurality of upstanding fastening elements are present at a density ranging from 1,000 elements per square centimeter to 5,000 elements per square centimeter, and the combined cross-sectional area of ​​the spaced apart caps is between 20% and 70% of the area of ​​the mechanical fastener. The spaced apart caps are circular, elliptical, or a regular polygon having at least five sides, with no dimension greater than 300 micrometers.

[0007] In another aspect, the present disclosure provides a laminate having the mechanical fastener attached to a carrier.

[0008] In yet another aspect, the present disclosure provides an absorbent article comprising said mechanical fastener or said laminate.

[0009] As used herein, terms such as "a," "an," and "the" do not refer only to a singular entity but include general classes used to describe particular examples. These terms are used synonymously with "at least one." The phrases "at least one" and "comprising at least one of," when followed by a list, refer to any single item in the list or any combination of two or more items. All numerical ranges are inclusive of their endpoints, unless otherwise stated, and include non-integer values ​​between the endpoints.

[0010] As used herein, the term "upstanding" refers to posts that protrude from a thermoplastic backing and includes posts that stand perpendicular to the backing as well as posts that stand at angles other than 90 degrees.

[0011] The term "spaced-apart" means that the caps are formed so that they do not touch one another, i.e., "spaced-apart" caps do not touch one another when the thermoplastic backing is in an unflexed state.

[0012] The term "multiple" means one or more and can include any number of upstanding fastener elements.

[0013] The terms "first" and "second" are used herein as relative concepts only. Unless otherwise specified, these terms are used for convenience in describing the embodiments of the present disclosure. In this specification, the "first" surface of the thermoplastic backing carries the upstanding fastener elements, and the "second" surface is located opposite the first surface.

[0014] The above summary of the present disclosure is not intended to describe all disclosed embodiments or every embodiment of the present disclosure. The following description more particularly illustrates exemplary embodiments. Accordingly, the drawings and the following description are provided for illustrative purposes only and should not be read to unduly limit the scope of the present disclosure. [Brief explanation of the drawings]

[0015] A more complete understanding of the present disclosure can be obtained from the detailed description of various embodiments of the present disclosure when considered in conjunction with the following drawings, in which: [Figure 1] FIG. 1 is a side view of one example of an upstanding fastening element on a thermoplastic backing useful in the mechanical fasteners of the present disclosure, showing various dimensions of said upstanding fastening element.

[0016] [Figure 2] FIG. 2 is a perspective view of an example of a disposable absorbent article including a mechanical fastener according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] Embodiments of the present disclosure will now be described in detail with reference to the following drawings, in which one or more examples of the present disclosure are shown. Features illustrated or described as part of one embodiment can be used in combination with other embodiments to yield yet a third embodiment. The present disclosure is intended to include these combinations and other modifications and variations.

[0018] 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 said thermoplastic backing 14. As in the embodiment shown in FIG. 1 , the plurality of upstanding fastening elements 11 have struts 10 having integrally formed proximal ends 10a attached to the thermoplastic backing 14 and distal ends 10b including spaced apart caps 12 having a cross-sectional area greater than that of the struts 10. The caps 12 extend beyond the struts by an overhang distance of "o". The height "h" of the upstanding fastening elements is the distance between the thermoplastic backing 14 and the distal ends 10b of the upstanding fastening elements 11 and is shown in FIG. 1. Additionally, FIG. 1 shows the thickness "t" of the thermoplastic backing 14, the width "w" of the struts at the base, and the width "w" of the struts just below the cap. 1 " and the cap width "w 2 In this application, all dimensions of the upstanding fastener elements described with reference to Figure 1 and defined in the claims are to be measured by optical microscopy.

[0019] In the mechanical fasteners of the present disclosure, the density of the upstanding fastening elements is 1000 elements per square centimeter (cm 2 )(6450 pieces / square inch(in 2 ))~5000 pieces / cm 2 (32250 pieces / in 2 ), 4000 pieces / cm 2 (25800 pieces / in 2 ), or 3000 pieces / cm 2 (19350 pieces / in2 In some embodiments, the density of the upstanding fastener elements is in the range of: 1000 elements / cm 2 (6450 pieces / in 2 )~1400 pieces / cm 2 (9030 pieces / in 2 ), 1050 pieces / cm 2 (6770 pieces / in 2 )~1400 pieces / cm 2 (9030 pieces / in 2 ), 1050 pieces / cm 2 (6770 pieces / in 2 )~5000 pieces / cm 2 (32250 pieces / in 2 ), 1600 pieces / cm 2 (10320 pieces / in 2 )~5000 pieces / cm 2 (32250 pieces / in 2 ), 1600 pieces / cm 2 (10320 pieces / in 2 )~4000 pieces / cm 2 (25800 pieces / in 2 ), 1600 pieces / cm 2 (10320 pieces / in 2 )~3000 pieces / cm 2 (19350 pieces / in 2 ), 1500 pieces / cm 2 (9675 pieces / in 2 )~4000 pieces / cm 2 (25800 pieces / in 2 ), 1650 pieces / cm 2 (10642 pieces / in 2 )~4000 pieces / cm 2 (25800 pieces / in 2 ), or 1650 pieces / cm 2 (10642 pieces / in 2 )~3000 pieces / cm 2 (19350 pieces / in 2 In some embodiments, the density of the upstanding fastener elements is about 1240 elements / cm 2 (8000 pieces / in 2 ) and in some embodiments, the density of the upstanding fastener elements is about 2480 elements / cm2 (16000 pieces / in 2 )

[0020] In some embodiments, the distance between the posts (i.e., pin spacing) is approximately equal in both directions. That is, in such embodiments, the posts 10 of the upstanding fastener elements are substantially evenly spaced. By "substantially evenly spaced," it is meant that the distance between the posts 10 varies by up to 10%, 7.5%, or 5%. Various arrangements of the upstanding fastener elements may be useful. Examples include square lattice arrangements, staggered arrangements, and sinusoidal arrangements.

[0021] Referring again to FIG. 1, the maximum width dimension of the spaced apart caps 12, "w 2 " is 300 micrometers (μm) or less. 2 If the width dimension "w" exceeds 300 μm, the caps may bend when the mechanical fastener is exposed to peel forces, reducing engagement strength. Additionally, the width dimension of the caps must allow them to be spaced apart. As described in U.S. Pat. No. 8,845,943 (Hertlein et al.), if the caps are in contact with each other, the upstanding elements cannot engage with the loops and will not function as mechanical fastener elements. The width dimension "w" 2 " is measured when viewing the cap from above. The term "width dimension" should be understood to mean the diameter of a cap 12 having a circular cross section. If the cap 12 has multiple width dimensions (e.g., a cap with an oval cross section), the width dimension "w 2 " is measured at the widest point of the cap 12 (i.e., the major axis of the ellipse). In some embodiments, the width dimension "w" of the spaced apart cap 12 2 In some embodiments, the width dimension "w" of the spaced apart caps 12 is in the range of 150 μm to 300 μm, or in the range of 150 μm to 270 μm. 2 " is in the range of 80 μm to 245 μm, or in the range of 80 μm to 225 μm. Furthermore, in some embodiments, the density of the plurality of upstanding fastener elements is 1000 pieces / cm2 ~1400 pieces / cm 2 and the dimension of the spaced apart caps is in the range of 150 μm to 300 μm or 150 μm to 270 μm. Also, in some embodiments, the density of the plurality of upstanding fastener elements is 1500 pieces / cm 2 ~4000 pieces / cm 2 and the dimensions of the spaced caps range from 80 μm to 225 μm.

[0022] In mechanical fasteners according to the present disclosure, the density of the upstanding fastening elements and the cap area can be used to calculate the total cap area within the mechanical fastener. The total cross-sectional area of ​​the caps ranges from 20% to 70% of the area of ​​the mechanical fastener. This percentage can be calculated by dividing the total cap area by the area of ​​the entire mechanical fastener. In some embodiments, the total cross-sectional area of ​​the caps ranges from 25% to 70%, 20% to 65%, 25% to 60%, or 31% to 60% of the area of ​​the mechanical fastener.

[0023] The upstanding fastener elements in the mechanical fasteners of the present disclosure can have a variety of shapes. The fastener elements can be mushroom-shaped or nail-shaped (i.e., with an enlarged head that is circular, elliptical, or regular polygonal relative to the post). Upstanding fastener elements with these shapes are generally considered multidirectional. In some embodiments, the cap extends beyond at least two opposing sides of the post. As such, the cap has an overhang, as described below. The extent of the overhang on the two opposing sides may be equal or unequal. In some embodiments, the fastener element is mushroom-shaped with an enlarged head that is circular or elliptical relative to the post. In some embodiments, the cap extends beyond the post in all directions, but the amount of overhang may vary in different directions. In some embodiments, at least a portion of the spaced apart caps deflect toward the thermoplastic backing. This can be performed after the cap is formed, for example, using the methods described below.

[0024] The spaced apart caps in the mechanical fasteners according to the present disclosure have a cross-sectional shape that is circular, elliptical, or a regular polygon having at least five sides. The regular polygon shape can be, for example, a pentagon, hexagon, octagon, decagon, or dodecagon. In some embodiments, the regular polygon shape is a regular hexagon. A regular polygon refers to a polygon with all equal angles and all equal sides. In a regular polygon cap, the corners may be slightly rounded or curved, but the shape is still recognized as having five sides (or six sides in some embodiments). In some embodiments, the cap has a circular (or approximately circular) cross-sectional shape. By approximately circular, it is meant that slight deviations from circularity due to the manufacturing process may be included, as would be understood by one of ordinary skill in the art.

[0025] The spaced caps can have a grooved or smooth surface. In some embodiments, the spaced caps have a smooth surface. In some embodiments, when the spaced caps have a grooved surface, it is useful for the total cross-sectional area of ​​the mechanical fastener caps to be in the range of 20% to 40% of the area of ​​the mechanical fastener. For example, as shown in the examples below, this is effective for achieving a softer feel.

[0026] Mechanical fasteners according to the present disclosure, in any of the above density and cap area embodiments, provide an unexpectedly soft feel when the upstanding fastening elements contact human skin, and in some embodiments, it is difficult to distinguish the feel of the side of the mechanical fastener with the fastening elements disposed thereon from the side without the fastening elements.

[0027] The thermoplastic backing of the mechanical fasteners according to the present disclosure can have a variety of thicknesses. In some embodiments, the thickness "t" of the thermoplastic backing in the mechanical fasteners of the present disclosure ranges from 20 μm to 200 μm. In some embodiments, the thickness "t" of the thermoplastic backing ranges from 30 μm to 100 μm, 30 μm to 90 μm, 30 μm to 80 μm, 25 μm to 80 μm, or 35 μm to 60 μm.

[0028] Mechanical fasteners according to the present disclosure generally feel soft and flexible when bent. In this disclosure, bending flexibility is measured using a KES-FB2-S Pure Bending Tester manufactured by Kato Tech Co., Ltd., Kyoto, Japan, according to the method described in the Examples below. In some embodiments, the bending flexibility of the mechanical fastener is at least 0.01 (gram-force (gf) × centimeter (cm)) / cm (gf·cm / cm), and does not exceed 0.1 gf·cm / cm, 0.09 gf·cm / cm, 0.08 gf·cm / cm, 0.07 gf·cm / cm, 0.06 gf·cm / cm, or 0.05 gf·cm / cm.

[0029] In some embodiments of mechanical fasteners according to the present disclosure, the maximum height "h" of the upstanding fastening elements 11 is 350 μm or less, and in some embodiments, 325 μm or less, or 300 μm or less. In some embodiments, the minimum height "h" of the upstanding fastening elements 11 of mechanical fasteners according to the present disclosure is 80 μm or more, and in some embodiments, 100 μm, 140 μm, or 150 μm or more. In some embodiments, the height "h" of the upstanding fastening elements 11 of mechanical fasteners according to the present disclosure is in the range of 150 μm to 300 μm, 80 μm to 350 μm, 90 μm to 335 μm, 100 μm to 325 μm, 100 μm to 300 μm, or 155 μm to 250 μm.

[0030] Typically, the upstanding fastening elements 11 of mechanical fasteners according to the present disclosure have an aspect ratio (i.e., the ratio of height "h" to widest width dimension "w") of about 2:1, 1.5:1, or 1.2:1 or less. The struts 10 can have a cross-section with a widest width dimension "w" of 250 μm or less and 75 μm or more. In some embodiments, the struts 10 have a cross-section with a width dimension "w" ranging from 75 μm to 200 μm or from 85 μm to 190 μm. The term "width dimension" should be understood to include the diameter of a strut 10 having a circular cross-section. When the strut 10 has multiple width dimensions (e.g., a strut with an oval cross-section), the width "w" refers to the widest width dimension, and the aspect ratios described herein are the height divided by the widest width dimension.

[0031] In a mechanical fastener according to the present disclosure, an upstanding fastening element 11 made by any of the methods described below can have, for example, a strut 10 that tapers from a proximal end 10a to a distal end 10b. The proximal end 10a can have a width dimension "w" that is greater than the strut 10 adjacent the cap 12, which is the "w" dimension shown in FIG. 1 In some embodiments, the width dimension of the support 10 just below the cap, "w 1 " ranges from 60 μm to 200 μm, 60 μm to 175 μm, 65 μm to 175 μm, or 75 μm to 150 μm. This tapered shape may facilitate removal of the posts 10 from the mold surface in the methods described below.

[0032] The mechanical fastener elements of the mechanical fasteners described herein have spaced apart caps, which have a cross-sectional area that is greater than the cross-sectional area of ​​the struts. In some embodiments, the cross-sectional area of ​​the struts extends beyond the area immediately below the caps (e.g., width "w 1 "). In some embodiments, the ratio of the width dimension of the cap to the width dimension measured at the proximal end of the post is typically at least 1.01:1 or 1.2:1, and can be up to 2:1. The width "w" of the cap 12 2 " and the width "w1 " refers to the cap overhang "o". Specifically, the cap overhang "o" in the illustrated embodiment is calculated by the following formula: (Cap width "w 2 - width of the strut at the distal end "w 1 " )÷2 In some embodiments of mechanical fasteners according to the present disclosure, the overhang distance is 90 μm or less. In other words, the overhang extends beyond the post by a maximum of 90 μm. In some embodiments, the overhang is 80 μm or less, 70 μm or less, 60 μm or less, or 50 μm or less. 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 90 μm, 10 μm to 80 μm, 10 μm to 60 μm, or 15 μm to 65 μm.

[0033] In some embodiments, the basis weight of the mechanical fastener is 100 grams per square meter (gsm) or less, 95 gsm or less, or 90 gsm or less. It may be desirable to have as low a basis weight as possible to minimize the amount of material used in manufacturing the mechanical fastener. In some embodiments, the basis weight of the mechanical fastener is at least 25 gsm, 45 gsm, 50 gsm, 55 gsm, 60 gsm, 70 gsm, greater than 75 gsm, or 76 gsm or greater. In some embodiments, the basis weight of the mechanical fastener is in the range of 45 gsm to 95 gsm, 55 gsm to 95 gsm, or 76 gsm to 95 gsm. Various factors affect the basis weight of a mechanical fastener. Mechanical fasteners according to the present disclosure have a high density of upstanding fastening elements, which can result in a large post width (e.g., "w" and "w"). 1 "), height, and thickness of the thermoplastic backing can be useful to reduce the basis weight of the mechanical fastener.

[0034] Many thermoplastic materials can be used in the mechanical fasteners of the present disclosure. Suitable thermoplastic materials for the thermoplastic backing having the upstanding fastener elements include polyolefin homopolymers (e.g., polyethylene, polypropylene), copolymers of ethylene, propylene, and / or butylene, ethylene-containing copolymers (e.g., ethylene-vinyl acetate, ethylene-acrylic acid), polyesters (e.g., poly(ethylene terephthalate), polyethylene butyrate, polyethylene naphthalate), polyamides (e.g., poly(hexamethylene adipamide)), polyurethanes, polycarbonates, poly(vinyl alcohol), ketone-based resins such as polyether ether ketone (PEEK), polyphenylene sulfide, poly(acrylonitrile-butadiene-styrene) (ABS resin), plasticized polyvinyl chloride (PVC), and mixtures thereof. Typically, polyolefins (e.g., polyethylene, polypropylene, polybutylene, ethylene copolymers, propylene copolymers, butylene copolymers, and copolymers and blends thereof) are used as thermoplastic materials. In some embodiments, the thermoplastic material comprises polypropylene. In some embodiments, the bulk flexural modulus of the thermoplastic material is at least 300 megapascals (MPa), 500 MPa, or 1000 MPa. In some embodiments, the bulk flexural modulus of the thermoplastic material is 3000 MPa or less, 2500 MPa or less, or 2000 MPa or less. The various thermoplastic materials described above can be prepared as masterbatches with desired properties (e.g., color). However, the presence or absence of dyes, pigments, or other colorants is not required for the present disclosure.

[0035] In some embodiments, a thermoplastic backing having upstanding fastener elements can be made from a multilayer or multicomponent thermoplastic meltstream. This allows the fastener elements to be formed at least partially from a thermoplastic material different from the thermoplastic material that primarily constitutes the backing. For example, various configurations of upstanding posts formed from multilayer meltstreams are shown in U.S. Pat. No. 6,106,922 (Cejka et al.). Multilayer or multicomponent meltstreams can be formed by any conventional method. For example, multilayer meltstreams can be formed using a multilayer feedblock, such as that shown in U.S. Pat. No. 4,839,131 (Cloeren). Multicomponent meltstreams having regions or domains containing different components can also be used. Useful multicomponent meltstreams can be formed using an inclusion coextrusion die or other known methods, such as those shown in U.S. Pat. No. 6,767,492 (Norquist et al.).

[0036] In mechanical fasteners according to the present disclosure, the thermoplastic backing and the upstanding posts are integral (i.e., formed simultaneously as a single 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 having an essentially uniform thickness, with the upstanding fastening elements directly attached to the thermoplastic backing. The upstanding posts on the backing can be made, for example, by conventional die extrusion and cast molding techniques. In some embodiments, the thermoplastic material is fed to a continuously moving mold surface with cavities having the inverse shape of the upstanding posts. The height of the posts is determined by the depth of the cavities. The thermoplastic material can be passed through a nip between two rolls or a nip between a die face and a roll surface, with at least one roll having a cavity (i.e., at least one roll is a tool roll). Pressure provided by the nip forces the resin into the cavities. In some embodiments, a vacuum can be used to evacuate the cavities to facilitate filling the cavities. The nip typically has a gap sufficient to allow an integral backing to form over the cavity. The mold surface and cavity can be cooled with air or water, if desired, before stripping the integrally formed backing and upstanding posts from the mold surface, such as with a stripper roll.

[0037] Suitable tool rolls are manufactured, for example, by forming a series of holes having the inverse shape of the upstanding posts in the cylindrical surface of a metal mold or sleeve (e.g., by computer numerical control (CNC) drilling, photoetching, using electroformed printed sleeves, laser drilling, electron beam drilling, metal punching, direct machining, or lost-wax casting). Other suitable tool rolls include those formed from a series of plates defining a plurality of post-forming cavities around their periphery, as described, for example, in U.S. Pat. No. 4,775,310 (Fischer). The cavities can be formed in the plates by, for example, drilling or photoresist techniques. Further suitable tool rolls include wire-wound rolls, the manufacturing methods of which are described, for example, in U.S. Pat. No. 6,190,594 (Gorman et al.). The exposed surfaces of the mold, sleeve, plate, or wire can be coated to impart surface properties. For example, coatings can be used to impart improved wear resistance, controlled release characteristics, and controlled surface roughness. If a coating is present, it can be selected so that the adhesion of the thermoplastic material to the tool roll is less than the cohesive strength of the thermoplastic material when the thermoplastic backing is removed from the tool roll.

[0038] Another method for forming upstanding posts in a thermoplastic backing is to use a flexible mold belt that defines an array of upstanding post-shaped cavities, as described in U.S. Patent No. 7,214,334 (Jens et al.). The mold belt is positioned around first and second rolls, and a source of molten thermoplastic material is positioned to supply thermoplastic material to the mold belt. The apparatus is configured to apply pressure within the gap to force plastic resin into the upstanding post-shaped cavities of the mold belt, forming the array of upstanding posts while forming the thermoplastic web layer.

[0039] To form the upstanding fastener elements of the mechanical fastener according to the present disclosure, the upstanding posts on the backing can have a variety of heights. This may be altered, for example, after the capping process described below. For example, the upstanding posts can have a height of up to 400 micrometers (μm) on the backing. In some embodiments, the maximum height is 350 μm or less, or 300 μm or less. The minimum height of the upstanding posts is at least 150 μm in some embodiments, and at least 160 μm, 175 μm, or 200 μm in other embodiments. Useful heights of the upstanding posts before capping range from 150 μm to 400 μm, or from 150 μm to 350 μm.

[0040] The resulting post after ejection from the cavity typically does not have a cap, but can be transformed into the upstanding fastener elements described herein using the capping method described in U.S. Pat. No. 5,607,635 (Melbye et al.). Generally, the capping method involves deforming the tip of the upstanding post using heat and / or pressure. When both heat and pressure are used, they may be applied sequentially or simultaneously. In some embodiments, the transformation involves contacting the distal end of the upstanding post with a heated surface. The heated surface can be flat or textured, such as those described in U.S. Pat. No. 6,708,378 (Parellada et al.) and U.S. Pat. No. 5,868,987 (Kampfer et al.). In some embodiments, when the thermoplastic backing having the upstanding fastener elements is an infinitely long web, the transformation of the distal end of the post to form a cap involves moving the web in a first direction through a nip having a heated surface member and an opposing surface member, with the heated surface member contacting the distal end. In these embodiments, the heated surface member may be, for example, a capping roll. In some embodiments, the surface contacting the distal end may not be heated. In these embodiments, deformation is achieved by pressure alone, without heating. In some embodiments, the heated surface member may be a heated roll facing a curved support surface. The curved support surface forms a variable nip and has a variable nip length, as described in U.S. Pat. No. 6,368,097 (Miller et al.). The curved support surface may be curved toward the heated roll. The heated roll may include a feeding mechanism that feeds a thermoplastic backing with upstanding posts into the variable nip. This configuration compressively engages the web between the heated roll and the support surface. In some embodiments, heating is performed at a temperature below the melting point of the distal ends of the posts. If the thermoplastic material used to form the upstanding posts is a copolymer (e.g., a copolymer of ethylene and propylene), the distal end may have multiple melting points. In these embodiments, "below the melting point of the distal ends of the posts" means below at least one melting point.

[0041] In some embodiments, the distal caps of the upstanding fastening elements are reshaped after formation, for example, by passing the thermoplastic backing with the capped posts through the gapped nip of a heated rubber roll and a backup roll, which forces the overhanging portion of the distal cap that extends beyond the posts down toward the backing. This process is described in US Pat. No. 6,132,660 (Kampfer).

[0042] In addition to the continuous processes described above, it is envisioned that the thermoplastic backing having upstanding fastening elements can also be made using a batch process (e.g., single-piece injection molding). The thermoplastic backing can have any suitable dimensions, but it can be useful for the length (L) and width (W) dimensions to be at least 10 centimeters.

[0043] Another method for forming a thermoplastic backing with upstanding fastening elements is profile extrusion. This method is described, for example, in U.S. Pat. No. 4,894,060 (Nestegard). Typically, this method involves passing a thermoplastic flow stream through a die lip patterned by, for example, electronic discharge machining, to form a web with downweb ridges. The ridges are then sliced ​​transversely along their elongation at intervals to form upstanding fastening elements with small spacings using a cutting blade. The spacing is then expanded by stretching. It should be understood, however, that "upstanding fastening elements" does not include the ridges prior to cutting. These ridges themselves are not considered to have "loop-engaging overhangs" because they cannot engage with loops prior to being cut and stretched. In some embodiments, mechanical fasteners according to the present disclosure are not manufactured by profile extrusion.

[0044] In mechanical fasteners according to the present disclosure, the upstanding fastening elements may be made, for example, by any of the methods described above, and may have a variety of cross-sectional shapes. For example, the cross-sectional shape of the struts can be polygonal (e.g., square, rectangular, hexagonal, pentagonal). The polygon may or may not be a regular polygon. The cross-sectional shape of the struts can also be curved (e.g., circular or elliptical). In some embodiments, the cross-sectional shape of the struts is a regular polygon having at least five sides. The regular polygon shape can be, for example, a pentagon, hexagon, octagon, decagon, or dodecagon. In some embodiments, the regular polygon shape is a regular hexagon. In regular polygon struts, the corners may be slightly rounded or curved. In some embodiments, the struts taper in size from the proximal end to the distal end.

[0045] The overhangs of the upstanding fastening elements described herein are generally considered to have loop-engagement properties. The term "loop-engagement properties" as used herein refers to the ability of the upstanding fastening elements to be mechanically coupled with a loop material. The loop-engagement properties of hook elements can be measured and defined using standard woven, nonwoven, or knitted fabrics. The region of the strut with a distal end having a loop-engagement overhang generally provides at least a higher peel strength, a higher dynamic shear strength, or a higher dynamic friction when combined with a loop material than the region of the strut without the loop-engagement overhang.

[0046] The thermoplastic backing can have an essentially uniform cross-section, or the thermoplastic backing can have additional structure in addition to that provided by the upstanding fastener elements, which can be imparted, for example, by at least one of the forming rolls described above.

[0047] In some embodiments, the thickness of the thermoplastic backing described in any of the above embodiments is achieved in mechanical fasteners according to the present disclosure by the gap between two rolls or the nip between a die face and a roll in an extrusion and cast molding process. An endless metal belt, a polymer belt, or a polymer-coated metal belt may be useful to provide uniform pressure within the nip. In some embodiments, the thickness of the thermoplastic backing does not change with stretching. In some embodiments, the thermoplastic backing does not have stretch-induced molecular orientation. Whether a thermoplastic backing has stretch-induced molecular orientation can be determined by standard spectroscopic analysis of the birefringence properties 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.

[0048] In some embodiments, the thermoplastic backing has stretch-induced molecular orientation. In some of these embodiments, the thermoplastic backing is stretched in at least one direction (e.g., the machine direction) by a ratio of 1.1 to 4. For example, if the thermoplastic backing is an infinitely long web, uniaxial stretching in the machine direction can be achieved by passing the thermoplastic web over rolls driven at different speeds. The most versatile stretching method is the use of a flat film tensioner, which allows for uniaxial, sequential biaxial, and simultaneous biaxial stretching. This device achieves uniaxial, sequential biaxial, or simultaneous biaxial stretching by gripping opposing edges of the thermoplastic web with clips, grippers, or other film edge gripping means and propelling the gripping means at different speeds in the desired direction. Increasing the 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 performed by the methods and apparatus described, for example, in U.S. Patent No. 7,897,078 (Petersen et al.) and the references cited therein. Flat film stretching equipment is commercially available, for example, from Bruckner Maschinenbau GmbH, Siegsdorf, Germany.

[0049] In this application, a retardation imaging system "LC-PolScope" available from Lot-Oriel GmbH & Co., Darmstadt, Germany, is used to measure whether a thermoplastic backing has stretch-induced molecular orientation. The measurement is performed using a microscope "DMRXE" available from Leica Microsystems GmbH, Wetzlar, Germany, and a digital CCD color camera "RETIGA EXi FAST 1394" available from QImaging, Inc., Surrey, British Columbia, Canada. The microscope is equipped with a 546.5 nm interference filter and a 10x / 0.25 objective lens available from Cambridge Research & Instrumentation, Inc., Hopkinton, Massachusetts, USA.

[0050] In any embodiment of the mechanical fastener according to the present disclosure, the thermoplastic backing may be in roll form. For example, a mechanical fastener patch may be cut to a size appropriate for a desired application. In this application, the thermoplastic backing may be a patch cut to the desired size. In some embodiments, the second surface of the thermoplastic backing (i.e., the surface opposite the first surface from which the upstanding fastener 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.

[0051] In some embodiments of the mechanical fastener according to the present disclosure, the thermoplastic backing is not bonded to the carrier, at least during initial formation. 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 carrier. The thermoplastic backing may be bonded to the carrier, for example, by lamination (e.g., extrusion lamination), adhesive (e.g., pressure-sensitive adhesive), or other bonding methods (e.g., ultrasonic bonding, compression bonding, or surface bonding). The thermoplastic backing may also be bonded to the carrier during formation of the thermoplastic backing having upstanding posts. The resulting article is a fastener laminate, such as a fastener tab bonded to the backsheet of an absorbent article, useful for joining the front and rear waist regions of the absorbent article.

[0052] In some embodiments, the carrier may be bonded to the second surface of the thermoplastic backing and may be continuous (i.e., without through holes) or discontinuous (e.g., with through holes or pores). The carrier may comprise a variety of suitable materials, including woven webs, nonwoven webs (e.g., spunbond webs, spunlace webs, airlaid webs, meltblown webs, and bonded carded webs), textiles, plastic films (e.g., monolayer or multilayer films, coextruded films, or films containing a foam layer), and combinations thereof. In some embodiments, the carrier is a fibrous material (e.g., woven, nonwoven, or knitted fabric). The term "nonwoven," when used with respect to a carrier or web, means having a structure in which individual fibers or threads are not arranged in a discernible pattern, such as in a knitted fabric. Nonwoven fabrics or webs may be formed by processes such as meltblowing, spunbonding, spunlace processing, and bonded carded web processing. In some embodiments, the carrier comprises multiple layers of nonwoven material, such as at least one layer of meltblown nonwoven and at least one layer of spunbond nonwoven, or a combination of other suitable nonwoven materials. For example, the carrier can be a spunbond-meltbond-spunbond (SMS), spunbond-spunbond (SS), or spunbond-spunbond-spunbond (SSS) multi-layer material. Alternatively, the carrier can be a composite web comprising a nonwoven layer and a high-density film layer.

[0053] Fibre materials that provide useful carriers can be made of natural fibres (e.g., wood or cotton fibres), synthetic fibres (e.g., thermoplastic fibres), or a combination of natural and synthetic fibres. Exemplary materials for forming thermoplastic fibres include polyolefins (e.g., polyethylene, polypropylene, polybutylene, ethylene copolymers, propylene copolymers, butylene copolymers, and copolymers and blends of these polymers), polyesters, polyamides. The fibres may also be multicomponent, e.g., having a core of one thermoplastic material and a sheath of another thermoplastic material.

[0054] One or more zones of the carrier comprise an elastically extensible material that is stretchable in at least one direction and can stretch when a force is applied and return to approximately its 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 refer to materials that do not exhibit recovery from stretch or deformation and may be useful in the carrier.

[0055] The mechanical fasteners of the present disclosure are useful components of fastening systems that include a mechanical fastener and a loop material. The mechanical fasteners of the present disclosure can be used with a wide variety of different loop materials. In some embodiments, the loop material is a low-loft loop material, which is suitable for use in fastening systems due to its low cost and low material usage. Examples of low-loft materials include nonwoven materials, which may be made, for example, from any of the materials described above for the carrier. In some embodiments, the fiber basis weight of the loop material ranges from 10 grams per square meter (gsm) to 50 gsm. Fiber basis weight refers to the basis weight of the fibers alone in the loop material (e.g., measured without the backing).

[0056] The fastener laminate formed after joining the thermoplastic backing to the carrier is useful, for example, in absorbent articles. One example of an absorbent article has at least a front waist region, a rear waist region, and a longitudinal centerline bisecting the front and rear waist regions. In this absorbent article, at least one of the front or rear waist regions includes a structured surface produced by the methods described herein. The fastener laminate can be in the form of a fastener tab that is bonded to at least one of the front or rear waist regions of the absorbent article and extends outward from at least one of the left or right longitudinal edges of the absorbent article. In another embodiment, the fastener laminate can be an integral ear portion of the absorbent article.

[0057] FIG. 2 is a schematic perspective view illustrating one embodiment of an absorbent article according to the present disclosure. The absorbent article is a diaper 60 having an hourglass shape. The diaper includes an absorbent core 63 disposed between a liquid-permeable topsheet 61 that contacts the wearer's skin and an outwardly disposed liquid-impermeable backsheet 62. The diaper 60 includes a rear waist region 65 having two fastener tabs 70, which are located on 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 wearer. 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 left side to the right side of the wearer (or vice versa) (i.e., from longitudinal edge 64a to longitudinal edge 64b in the embodiment of Figure 2).

[0058] In FIG. 2 , fastener tab 70 is secured to rear waist region 65 via its manufacturer end 70a. A user end 70b of fastener tab includes a mechanical fastener 80 according to the present disclosure. In some embodiments, when diaper 60 is attached to a wearer's body, user end 70b of fastener tab 70 can be attached to a target area 68 including a fibrous material 72 disposed on backsheet 62 in front waist region 66. Examples of loop tape that may be applied to target area 68 to provide exposed fibrous material 72 are disclosed, for example, in U.S. Pat. No. 5,389,416 (Mody et al.), European Patent Application Publication No. 0,341,993 (Gorman et al.), and European Patent Application Publication No. 0,539,504 (Becker et al.). In other embodiments, backsheet 62 includes a woven or nonwoven fibrous layer that can interact with user end 70b of fastener tab 70 equipped with a mechanical fastener according to the present disclosure. Examples of such backsheets 62 are disclosed, for example, in U.S. Patent No. 6,190,758 (Stopper) and U.S. Patent No. 6,075,179 (McCormack et al.), and are described in the Examples below. Accordingly, in some embodiments, disposable absorbent articles according to the present disclosure do not include a target loop landing zone.

[0059] While the embodiment shown in Figure 2 is an absorbent article with fastener tabs, it is contemplated that the mechanical fasteners of the present disclosure will be equally useful in absorbent articles with larger hook areas, such as where the ear portions of the absorbent article themselves include mechanical fasteners of the present disclosure, or where the absorbent article has two target zone loop materials along a longitudinal edge of the backsheet in one waist region and two hook strips along a longitudinal edge of the opposing waist region.

[0060] The fastener laminate of the present disclosure is also useful as a fastener tab for a pant-type diaper, for example, as described in U.S. Pat. No. 5,531,732 (Wood). In some embodiments, the absorbent article of the present disclosure is a pant-type disposable diaper having a fibrous outer sheath or backsheet on which a fastener tab can be engaged. The fastener tab may be located in a seam or side panel portion of the pant diaper, and its free end may be engageable with the fibrous outer sheath or backsheet. The free end of the fastener tab is useful for gathering the side panel portion, for example, to adjust the fit or size of the waist circumference (i.e., waist fit or size) of the pant diaper. In some embodiments, the side panel portion does not include an integrally bonded absorbent core structure. In some embodiments, the pant diaper has at least one score line extending from the waist opening to one of the leg openings. This score line is typically near a side seam, may be located on the front side of the diaper, and may be parallel or non-parallel to the side seam. In some embodiments, the pant-type diaper has a pair of score lines, one on each side of the diaper. The score lines can be torn before or while the diaper is being placed on the wearer's torso. The free ends of the fastener tabs can then be used to refasten the diaper to fit snugly around the wearer's waist. The free ends of the fastener tabs are also useful as disposal means, for example, when the pant-type diaper is removed from the wearer (e.g., by tearing the side panels or the score lines). The fastener tabs typically remain in the side panel areas. The diaper can then be rolled up into a compact shape, and the fastener tabs can be used to hold the diaper in place.

[0061] Fastener laminates including mechanical fasteners according to the present disclosure may also be useful in absorbent articles such as sanitary napkins. Sanitary napkins typically include a backsheet intended to be placed adjacent to the wearer's undergarments. The backsheet may include a thermoplastic backing having spaced apart, upstanding, capped posts, which allow the sanitary napkin to be securely attached 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 attached to the backsheet using adhesive or other attachment mechanisms.

[0062] According to U.S. Patent No. 7,162,780 (Martin et al.), a skin-friendly hook element should have a ratio of the total hook head area to the total hook element area of ​​40% to 55%. However, it is possible to make hooks more skin-friendly by using softer resins or backings of varying thickness. Martin et al. state that hook densities of 1000 to 2000 hooks per square inch (155 to 310 hooks per square centimeter), 1200 to 1800 hooks per square inch (186 to 279 hooks per square centimeter), or 1300 to 1600 hooks per square inch (202 to 248 hooks per square centimeter) provide optimal spacing for skin-friendly and useful hook elements suitable for many garment applications. Given this technical suggestion, one skilled in the art would expect that higher hook densities and larger cap areas would be less useful because there would not be enough space between the hooks for loop engagement. Furthermore, as described in U.S. Pat. No. 8,845,943 (Hertlein et al.), when at least a portion of a cap is in contact with at least one adjacent cap, there is not enough space around the cap for multi-directional engagement of mechanical fasteners.

[0063] However, as shown in the following examples, some embodiments of mechanical fasteners according to the present disclosure unexpectedly exhibit improved softness compared to mechanical fasteners with 1600 hooks per square inch. Furthermore, even when the cap area percentage is in the range of 40% to 56%, the peel and shear values ​​of mechanical fasteners according to the present disclosure are superior to those of mechanical fasteners with 1600 hooks per square inch. See, for example, a comparison of Examples 1 and 3 with Comparative Examples 2 and 3, and a comparison of Example 7 with Comparative Example 5. On the other hand, when the cap area percentage is approximately equal in the range of 20% to 30%, mechanical fasteners with densities ranging from 1000 hooks per square centimeter to 5000 hooks per square centimeter exhibit a softer feel and comparable or better peel and shear performance than mechanical fasteners with densities of 1600 hooks per square inch. See, for example, a comparison of Examples 2 and 4 with Comparative Examples 2 and 3, and a comparison of Example 6 with Comparative Example 5.

[0064] [Regarding some embodiments of the present disclosure] In a first embodiment, the present disclosure provides a mechanical fastener comprising a thermoplastic backing and a plurality of upstanding fastening elements, each having a proximal end comprising a strut integrally formed with the thermoplastic backing and a distal end comprising spaced apart caps having a cross-sectional area greater than that of the struts, the plurality of upstanding fastening elements being present at a density ranging from 1000 elements per square centimeter or 1050 elements per square centimeter to 5000 elements per square centimeter, the combined cross-sectional area of ​​the spaced apart caps being between 20% and 70% of the area of ​​the mechanical fastener, the spaced apart caps being circular, elliptical, or a regular polygon having at least five sides, and the spaced apart caps having no dimension greater than 300 micrometers. In a second embodiment, the present disclosure provides a mechanical fastener. The mechanical fastener is the mechanical fastener described in the first embodiment, wherein the spaced apart caps extend beyond at least two opposing sides of the post. In a third embodiment, the present disclosure provides a mechanical fastener. The mechanical fastener is the mechanical fastener described in the first or second embodiment, wherein the total cross-sectional area of ​​the caps is in the range of 25% to 70%, 20% to 65%, 20% to 40%, 25% to 60%, or 31% to 60% of the area of ​​the mechanical fastener. In a fourth embodiment, the present disclosure provides a mechanical fastener. The mechanical fastener is the mechanical fastener described in any of the first to third embodiments, wherein at least a portion of the spaced apart caps deflects toward the thermoplastic backing. In a fifth embodiment, the present disclosure provides a mechanical fastener. In a sixth embodiment, the present disclosure provides a mechanical fastener, wherein the density of the plurality of upstanding fastener elements is in the range of 1000 elements / cm 2 to 1400 elements / cm 2 and the dimensions of the spaced apart caps are in the range of 150 micrometers to 270 micrometers.The mechanical fastener is the mechanical fastener according to any one of the first to fifth embodiments, wherein the density of the plurality of upstanding fastener elements is in the range of 1600 elements / square centimeter to 4000 elements / square centimeter. In a seventh embodiment, the present disclosure provides a mechanical fastener. The mechanical fastener is the mechanical fastener according to any one of the first to sixth embodiments, wherein the density of the plurality of upstanding fastener elements is in the range of 1500 elements / square centimeter to 4000 elements / square centimeter, and the dimension of the spaced caps is in the range of 80 micrometers to 245 micrometers.

[0065] In an eighth embodiment, the present disclosure provides a mechanical fastener according to any one of the first to seventh embodiments, wherein at least a portion of the posts narrow from the proximal end to the distal end. In a ninth embodiment, the present disclosure provides a mechanical fastener according to any one of the first to eighth embodiments, wherein the thickness of the thermoplastic backing is within a range of 30 micrometers to 100 micrometers, 30 micrometers to 80 micrometers, 25 micrometers to 80 micrometers, or 35 micrometers to 60 micrometers, and / or the bending flexibility of the mechanical fastener is at least 0.01 (gram-force x centimeter) / centimeter and at most 0.1, 0.09, 0.08, 0.07, 0.06, or 0.05 (gram-force x centimeter) / centimeter. In a tenth embodiment, the present disclosure provides a mechanical fastener according to any one of the first to ninth embodiments, wherein the thermoplastic backing is free of stretch-induced molecular orientation. In an eleventh embodiment, the present disclosure provides a mechanical fastener according to any one of the first to tenth embodiments, wherein the plurality of upstanding fastener elements are substantially evenly spaced. In a twelfth embodiment, the present disclosure provides a mechanical fastener according to any one of the first to eleventh embodiments, wherein the height of the plurality of upstanding fastener elements is within a range of 80 micrometers to 350 micrometers, 100 micrometers to 300 micrometers, or 150 micrometers to 300 micrometers. In a thirteenth embodiment, the present disclosure provides a mechanical fastener according to any one of the first to twelfth embodiments, wherein the width dimension "w1" of the post directly below the cap is within a range of 60 micrometers to 175 micrometers. In a fourteenth embodiment, the present disclosure provides a mechanical fastener according to any one of the first to thirteenth embodiments, wherein the spaced apart caps are smooth.In a fifteenth embodiment, the present disclosure provides a mechanical fastener according to any one of the first to thirteenth embodiments, wherein the spaced apart caps are grooved and the combined cross-sectional area of ​​the caps is within a range of 20-40% of the area of ​​the mechanical fastener. In a sixteenth embodiment, the present disclosure provides a mechanical fastener according to any one of the first to fifteenth embodiments, wherein the spaced apart caps are spaced apart circular caps. In a seventeenth embodiment, the present disclosure provides a mechanical fastener according to any one of the first to sixteenth embodiments, wherein the basis weight of the mechanical fastener is within a range of 45 grams per square meter to 95 grams per square meter, 55 grams per square meter to 95 grams per square meter, or 76 grams per square meter to 95 grams per square meter. In an eighteenth embodiment, the present disclosure provides a mechanical fastener according to any one of the first to seventeenth embodiments, wherein the mechanical fastener comprises polypropylene.

[0066] In a 19th embodiment, the present disclosure provides a laminate in which a mechanical fastener according to any one of the first to eighteenth embodiments is attached to a carrier. In a 20th embodiment, the present disclosure provides a laminate according to the 19th embodiment, wherein the carrier comprises a nonwoven fabric. In a 21st embodiment, the present disclosure provides an absorbent article comprising a mechanical fastener according to any one of the first to eighteenth embodiments. In a 22nd embodiment, the present disclosure provides an absorbent article according to the 21st embodiment, further comprising a front waist section and a rear waist section, wherein at least one of the front waist section or the rear waist section comprises a mechanical fastener. In a 23rd embodiment, the present disclosure provides an absorbent article according to the 21st or 22nd embodiment, wherein the absorbent article is an open-type diaper. In a 24th embodiment, the present disclosure provides an absorbent article according to the 21st embodiment, wherein the absorbent article is a pant-type diaper, and wherein the mechanical fastener is disposed on a seam or a tab of a side panel portion of the pant-type diaper.

[0067] In order that the present disclosure may be more fully understood, the following examples are presented, which are intended for illustrative purposes only and are not intended to limit the present disclosure in any way.

[0068] [example] [Test method] [Peeling evaluation] The mechanical fasteners of Examples 1-7 and Reference Examples 1-5 were evaluated using nonwoven loop materials taken from "MOONY" diapers manufactured by Unicharm (Tokyo, Japan). For peel evaluation, mechanical fastener specimens (25 millimeters (mm) in the machine direction (MD) × 20 mm in the cross direction (CD)) were attached to one end of a paper leader using single-sided adhesive tape. The nonwoven material was secured to a metal plate (50 mm × 100 mm (test direction)) using double-sided adhesive tape, with care taken to avoid damaging the loop surface or applying too much pressure. The mechanical fastener specimens were crimped using a 700-gram roller at a speed of 300 mm / min for one cycle (one cycle = one forward and one backward). The materials were positioned so that peeling occurred in the cross direction (CD) of the example specimens and the cross direction (CD) of the nonwoven. The 135-degree peel test was performed using a device registered under the trademark "TENSILON RTG-1225" manufactured by A&D Co., Ltd. (Tokyo, Japan). The metal plate was placed in a 135-degree peel jig, secured, and then the edge of the paper leader was clamped. The peel start point was the vertical bottom edge of the chuck. The separation speed was 300 mm / min. This evaluation was performed twice using new samples, and the average peel force was recorded. The results are shown in Tables 1 and 2 below.

[0069] [Shear evaluation] The mechanical fasteners of Examples 1-7 and Reference Examples 1-5 were evaluated using nonwoven loop material taken from Unicharm's "MOONY" diapers. The completed mechanical fastener specimens were prepared as 20 mm cross direction (CD) x 25 mm machine direction (MD) strips and attached to a 90 mm x 25 mm filament tape (3M, St. Paul, Minnesota, USA) leader. A 38-micrometer thick sheet of paper (70 mm x 25 mm) was used to cover the exposed adhesive on the filament tape. The nonwoven material (50 mm x 100 mm (cross direction)) was secured to a metal plate (50 mm x 100 mm (test direction)) using double-sided adhesive tape, with care taken to avoid damaging the loop surface or applying too much pressure. The mechanical fastener specimens were crimped using a 700-gram roller at a speed of 300 mm / min for one cycle (one cycle = one forward and one reverse). The materials were positioned so that shear testing was performed in the cross direction (CD) of the example mechanical fastener and the cross direction (CD) of the nonwoven fabric. Shear testing was performed using a device manufactured by A&D Co., Ltd., registered under the trademark "TENSILON RTG-1225." The leader of the example specimen was secured in the upper chuck of the device, and the nonwoven fabric specimen was secured in the lower chuck, with a small amount of slack. The device was started, and the upper chuck moved, recording the process until the example specimen was completely peeled from the loop specimen. The crosshead speed of the device was set to 300 mm / min. This evaluation was performed twice using new specimens, and the data were averaged. The average values ​​are shown in Tables 1 and 2.

[0070] [Pure bending evaluation] Flexural flexibility was measured using a KES-FB2-S pure bending tester manufactured by Kato Seisakusho (Kyoto, Japan). Test specimens for machine direction (MD) bending tests were prepared by cutting the mechanical fasteners of Examples 1-7 and Reference Examples 1-5 into strips measuring 20 mm in the cross direction (CD) by 100 mm in the machine direction (MD). Test specimens for cross direction (CD) bending tests were prepared by cutting the mechanical fasteners of Examples 1-7 and Reference Examples 1-5 into strips measuring 100 mm in the cross direction (CD) by 20 mm in the machine direction (MD). The test specimens were placed in a specimen holder and bent along the long axis. Bending was performed both toward and away from the fastener element. This evaluation was performed twice, and the data were averaged. The average flexural flexibility results are shown in Tables 1 and 2 below.

[0071] [Tactile evaluation] Six evaluators evaluated the tactile feel of the mechanical fasteners of Examples 1 to 7 and Reference Examples 1 to 5 by touching them with their hands and rated them on a scale of 1 to 10, where 1 is the softest and 10 is the roughest. The average of the six evaluation scores was calculated, and the results are shown in Tables 1 and 2 below.

[0072] [Basic weight] The basis weight was determined by weighing a sample of known area on an analytical balance.

[0073] [Dimensional Measurements] The measurements shown in Tables 1 and 2 were taken at 175x magnification using a Keyence VHX-1000 microscope manufactured by Keyence Corporation. The microscope is equipped with data acquisition software, a digital rangefinder, and a monitor.

[0074] [Examples (EX) 1 to 5 and Reference Examples (IE) 1 to 3] The mechanical fasteners of Examples 1-5 and Reference Examples 1-3 were fabricated using polypropylene "J842" manufactured by Hyosung Co., Ltd. of Korea, according to the method described in U.S. Pat. No. 5,845,375 (Miller et al.), except that the extrusion temperature was 255°C, the mold temperature was 79°C, and the extrusion speed was 30 meters / min. The circular holes in the molds of Examples 1-4 and Reference Example 1 were arranged in a staggered pattern (a staggered arrangement), with the spacing between identical rows in the X direction (X pitch) and the spacing between directly adjacent staggered rows (Y pitch) set, and the resulting hole density and upstanding post information are shown in Table 1. The circular holes in the molds of Reference Examples 2 and 3 were arranged in a square pattern, with the spacing between directly adjacent rows in the X direction (X pitch) and the spacing between directly adjacent rows in the Y direction (Y pitch) set, and the resulting hole density and upstanding post information are shown in Table 1. The holes were generally conical in shape and 350 μm deep. In Example 5, a thermoplastic backing with upstanding posts was stretched in the machine direction (MD) at a stretch ratio of 1.15:1. The upstanding fastener elements were provided with oval grooved caps according to the method described in U.S. Patent No. 5,868,987 (Kampfer et al.), and the cap shape was reformed by pushing the distal cap portion beyond the posts down toward the backing (this reforming process is described in U.S. Patent No. 6,132,660 (Kampfer)).

[0075] In Table 1, the density of the upstanding fastener elements (number per square inch), X pitch, Y pitch, basis weight, cap width in the cross direction (CD) and machine direction (MD), width of the posts adjacent to the thermoplastic backing "w" and width of the posts adjacent to the cap "w1", and backing thickness were recorded. The cap area ratio was calculated from the CD cap width and MD cap width. Examples 1-5 and Reference Examples 1-3 were evaluated for smoothness of touch, KES flexibility in the MD and CD, peel, and shear using the test methods described above. The results are shown in Table 1 below.

[0076] Table 1. Examples (EX) 1-5 and Reference Examples (IE) 1-3 with oval grooved caps [Table 1]

[0077] [Examples (EX) 6 and 7, and Reference Examples (IE) 4 and 5] The mechanical fasteners of Example 7 and Reference Examples 4 and 5 were fabricated by the methods described in Examples 1 to 5 and Reference Examples 1 to 3. A staggered array was used in Example 7 and Reference Example 4. A square array was used in Reference Example 5. The X-pitch and Y-pitch in both cases were set according to the definitions described above. The mechanical fastener of Example 6 was fabricated by the methods described in Examples 1 to 5 and Reference Examples 1 to 3, with the following modifications: The polypropylene used was "C700-35N" manufactured by Braskem, São Paulo, Brazil. The mold had a staggered array with regular hexagonal holes, and the X-pitch and Y-pitch were set according to the definitions described above.

[0078] In Examples 6 and 7 and Reference Examples 4 and 5, a flat capping roller was used to form a smooth cap instead of using the process described in U.S. Pat. No. 5,868,987 (Kampfer et al.). The caps in Example 7 and Reference Examples 4 and 5 were generally circular. The cap in Example 6 was generally hexagonal with rounded corners. The cap was then reshaped, and the distal cap portion that extended beyond the post was pressed down onto the backing (this reshaping process is described in U.S. Pat. No. 6,132,660 (Kampfer)).

[0079] In Table 2, the density of the upstanding fastener elements (number per square inch), X pitch, Y pitch, basis weight, width of the cap in the cross direction (CD) and machine direction (MD), width of the post adjacent to the thermoplastic backing "w" and width of the post adjacent to the cap "w 1 " and the backing thickness was recorded. The cap area ratio was calculated from the CD cap width and MD cap width.

[0080] Examples 6 and 7, and Reference Examples 4 and 5 were evaluated for tactile smoothness, KES flexibility in MD and CD, peel, and shear using the test methods described above. The results are shown in Table 2 below.

[0081] Table 2. Examples 6 and 7 with smooth caps and Reference Examples 4 and 5 [Table 2]

[0082] The present disclosure is not limited to the above-described embodiments, but is instead bound by the following claims and their equivalents.

Claims

1. 1. A mechanical fastener comprising: a thermoplastic backing; a plurality of upstanding fastener elements having posts having proximal ends integrally formed with said thermoplastic backing and distal ends including spaced apart caps having a cross-sectional area greater than the cross-sectional area of ​​said posts; and 1. A mechanical fastener, wherein the plurality of upstanding fastener elements are present at a density ranging from 1000 elements per square centimeter to 5000 elements per square centimeter, the combined cross-sectional area of ​​the spaced apart caps is in the range of 20% to 70% of the area of ​​the mechanical fastener, the spaced apart caps are circular, elliptical, or a regular polygon having at least five sides, and no dimension of the spaced apart caps exceeds 300 micrometers.

2. The mechanical fastener of claim 1 , wherein the spaced apart caps extend beyond at least two opposing sides of the post.

3. The mechanical fastener of claim 1 or 2, wherein at least a portion of the spaced apart caps deflects toward the thermoplastic backing.

4. 4. The mechanical fastener of claim 1, wherein a density of the plurality of upstanding fastener elements ranges from 1000 elements per square centimeter to 1400 elements per square centimeter, and a dimension of the spaced apart caps ranges from 150 micrometers to 270 micrometers.

5. The mechanical fastener of any one of claims 1 to 3, wherein the density of the plurality of upstanding fastener elements is in the range of 1600 elements per square centimeter to 4000 elements per square centimeter.

6. 4. The mechanical fastener of claim 1, wherein a density of the plurality of upstanding fastener elements ranges from 1500 elements per square centimeter to 4000 elements per square centimeter, and a dimension of the spaced apart caps ranges from 80 micrometers to 245 micrometers.

7. 7. The mechanical fastener of any one of claims 1 to 6, wherein the thermoplastic backing has a thickness in the range of 25 micrometers to 80 micrometers, or the mechanical fastener has a bending flexibility of at least 0.01 (gram-force x centimeter) / centimeter and not more than 0.1 (gram-force x centimeter) / centimeter.

8. The mechanical fastener of any one of claims 1 to 7, wherein the thermoplastic backing does not have stretch-induced molecular orientation.

9. The mechanical fastener according to any one of claims 1 to 8, wherein the plurality of upstanding fastener elements are substantially evenly spaced.

10. The mechanical fastener according to any one of claims 1 to 9, wherein the height of the plurality of upstanding fastener elements is in the range of 100 micrometers to 300 micrometers.

11. The mechanical fastener of any one of claims 1 to 10, wherein the spaced apart caps are smooth.

12. The mechanical fastener of any one of claims 1 to 11, wherein the spaced apart caps are spaced apart circular caps.

13. The mechanical fastener of any one of claims 1 to 12, having a basis weight in the range of 45 grams per square meter to 95 grams per square meter, or 76 grams per square meter to 95 grams per square meter.

14. A laminate comprising a mechanical fastener according to any one of claims 1 to 13 attached to a carrier.

15. An absorbent article comprising the mechanical fastener of any one of claims 1 to 13.

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