Hook-and-loop fasteners and molding devices

Abstract

A surface fastener (10) according to the present invention includes a base portion (11) and a plurality of engaging elements (20) formed integrally with the base portion (11), wherein: when the engaging elements (20) are seen from a machine direction (MD), a lower half portion of a stem portion (21) has a first shape (31) in which an outer surface (21a) is formed with a straight shape or a substantially straight shape; and when the engaging elements (20) are seen from an orthogonal direction (CD), the lower half portion of the stem portion (21) has a second shape (32) in which the outer surface (21a) includes a part that is curved toward a top surface of the base portion (11). It is thus possible to provide a surface fastener (10) that exhibits different structures and / or properties between the machine direction and the orthogonal direction.

Description

[Technical Field]

[0001] The present invention relates to a hook-and-loop fastener and a molding device used in the manufacture of the hook-and-loop fastener. [Background technology]

[0002] Conventionally, hook-and-loop fastener products have been known that combine a female hook-and-loop fastener having multiple loops (hereinafter referred to as a loop member) with a male hook-and-loop fastener that can be attached to and detached from the loop member (hereinafter the male hook-and-loop fastener will be simply referred to as a hook-and-loop fastener). The hook-and-loop fastener has, for example, a flat base portion and multiple engaging elements that protrude from the base portion and have a mushroom-like shape or the like.

[0003] Hook-and-loop fasteners are currently widely used in a wide variety of products, including products that are attached to and detached from the body, such as disposable diapers, diaper covers for infants, supports for protecting the joints of the limbs, lumbar corsets (lumbar pain belts), gloves, etc. An example of a hook-and-loop fastener used for disposable diapers and the like is disclosed in International Publication No. 2017 / 109902 (Patent Document 1).

[0004] The hook-and-loop fastener described in Patent Document 1 has a base portion and a plurality of engaging elements protruding from the base portion. Each engaging element in Patent Document 1 has a stem portion rising from the base portion and a disk-shaped engaging head portion integrally formed at the upper end of the stem portion. The engaging head portion has a plurality of minute claw portions protruding from the outer periphery of the engaging head portion.

[0005] The hook-and-loop fastener of Patent Document 1 is manufactured using a manufacturing device having a molding device for primary molding and a heating and pressing device for secondary molding. The molding device has a die wheel that rotates in one direction, a supply nozzle disposed opposite the outer circumferential surface of the die wheel, and a pickup roller disposed downstream of the supply nozzle in the direction of rotation of the die wheel.

[0006] The die wheel includes a cylindrical outer sleeve that serves as a die, a cylindrical inner sleeve that is disposed in close contact with the inside of the outer sleeve, and a drive roller that rotates the outer sleeve and the inner sleeve in one direction. The outer sleeve has a plurality of through holes that penetrate from the outer peripheral surface to the inner peripheral surface of the outer sleeve. The inner sleeve has a plurality of recesses on its outer peripheral surface. The heating and pressing device has a pair of upper and lower pressing rollers (calender rollers). By using such a manufacturing device, it is possible to manufacture the hook-and-loop fastener of Patent Document 1, which has a plurality of engaging elements each having minute claws provided on the outer periphery of the engaging head.

[0007] On the other hand, as a method for manufacturing a male hook-and-loop fastener, instead of using a molding device equipped with the single die wheel described above, a method is known in which a twin-roll type molding device is used that is equipped with a die wheel having multiple cavities on its outer surface and a pressure wheel arranged opposite the die wheel.

[0008] When using this twin-roll type molding device, molten synthetic resin material is supplied from a supply nozzle toward the gap between the opposing die wheel and pressure wheel, whereby the base portion is molded between the die wheel and pressure wheel, and the engaging elements (or primary elements before being molded into the engaging elements) are molded on the outer circumferential surface of the die wheel, allowing for continuous production of hook-and-loop fasteners. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2017 / 109902 Summary of the Invention [Problem to be solved by the invention]

[0010] When manufacturing a hook-and-loop fastener using the above-mentioned twin-roll type molding apparatus, it is possible to use a die wheel and a pressure wheel to mold a base portion thinner than, for example, the manufacturing method of Patent Document 1. However, with a twin-roll type molding apparatus, it is more difficult to fill the molten synthetic resin material into the multiple cavities formed on the outer peripheral surface of the die wheel than with, for example, the manufacturing method of Patent Document 1, and it is not possible to stably form the above-mentioned minute claw portions on each engaging element. Therefore, it was difficult to manufacture the hook-and-loop fastener of Patent Document 1, in which minute claw portions are formed on the engaging elements, using a twin-roll type molding apparatus.

[0011] On the other hand, when manufacturing a hook-and-loop fastener by supplying synthetic resin from a supply nozzle to one die wheel as in Patent Document 1, it is difficult to form a molded body by thinning the thickness of the base portion during primary molding compared to a twin-roll type molding device. This may reduce the flexibility of the hook-and-loop fastener and hinder weight and cost reduction of the hook-and-loop fastener.

[0012] In contrast to this, in recent years, in order to manufacture hook-and-loop fasteners having a thin base portion using a molding device having a single die wheel, it has been considered to mold a molded body (primary molded body) having a base portion in the molding device, and then perform a stretching process, for example, to stretch the base portion of the obtained molded body along the machine direction (MD) to make it thinner.

[0013] However, when a molded body (primary molded body) obtained using the molding device of Patent Document 1 is subjected to a stretching process along the machine direction (MD), the base portion is pulled in the machine direction within the stretching device, which may cause the base portion to break along the machine direction.

[0014] Furthermore, hook-and-loop fasteners manufactured by stretching in the machine direction may have reduced tear strength in the cross direction (CD) of the hook-and-loop fastener, and for example, when force is applied to the base portion of the hook-and-loop fastener, cross-direction tearing may occur, in which the base portion is torn in the cross direction. For this reason, when a hook-and-loop fastener is used in a disposable diaper, for example, when the hook-and-loop fastener is pulled and engaged with the loop member of the disposable diaper to maintain the diaper attached state, there is a possibility that the stretched base portion may tear or break in the cross direction. Note that the cross direction (CD) refers to the direction perpendicular to the machine direction (MD) during manufacturing.

[0015] To address the above-mentioned problems, it has become desirable to develop a hook-and-loop fastener that provides differences in structure, strength, etc. between the machine direction (MD) and the cross direction (CD).

[0016] The present invention has been made in consideration of the above-mentioned conventional problems, and its object is to provide a hook-and-loop fastener that exhibits different structures and / or properties between the machine direction and the orthogonal direction, and to provide a molding device used in the manufacture of such a hook-and-loop fastener. [Means for solving the problem]

[0017] In order to achieve the above object, the present invention provides a hook-and-loop fastener having a base portion and a plurality of engaging elements formed integrally with the base portion, each engaging element having a stem portion protruding from a surface of the base portion in a thickness direction of the base portion and an engaging head portion formed at a tip portion of the stem portion, wherein a cross section perpendicular to the thickness direction at least at an upper end portion of the stem portion has a circular or nearly circular shape, and the engaging head portion has a shape that expands from the tip portion of the stem portion to the entire direction perpendicular to the thickness direction, and wherein a lower half portion of the stem portion includes a portion in which, in a first shape of the engaging elements as viewed from the machine direction, an outer surface facing in a direction perpendicular to the machine direction is formed in a straight or substantially straight shape, and in a second shape of the engaging elements as viewed from the orthogonal direction, the outer surface facing in the machine direction is curved toward the surface of the base portion. The curved portion of the outer surface in the second shape is provided over 30% or more of the range in the up-down direction of the lower half of the stem portion, and the connecting portion connecting the stem portion to the base portion has an elliptical or approximately elliptical shape that is elongated in the machine direction. It is something.

[0018] In the hook-and-loop fastener of the present invention, it is preferable that in the second shape, the stem portion includes a portion in the upper half of the stem portion in which the outer surface facing the machine direction is formed in a straight or approximately straight shape, and that the portion of the second shape that is formed in a straight or approximately straight shape is formed over a shorter range than the portion of the first shape that is formed in a straight or approximately straight shape.

[0019] Another form of hook-and-loop fastener provided by the present invention is a hook-and-loop fastener made of synthetic resin, which has a base portion and a plurality of engaging elements formed integrally with the base portion, each engaging element having a stem portion protruding from the surface of the base portion in the thickness direction of the base portion and an engaging head portion formed at the tip portion of the stem portion, and the cross section perpendicular to the thickness direction at least at the upper end portion of the stem portion has a circular or nearly circular shape, and the engaging head portion has a shape that expands entirely from the tip portion of the stem portion in the direction perpendicular to the thickness direction, When the engaging element is viewed from the machine direction, a length in a direction perpendicular to the machine direction at a connecting portion of the stem portion that connects the stem portion to the base portion is defined as a first dimension, and when the engaging element is viewed from the orthogonal direction, a length in the machine direction at the connecting portion of the stem portion is defined as a second dimension, the stem portion has a shape in which the second dimension is larger than the first dimension, Under The half portion includes a portion in which, in the second shape of the engaging element when viewed from the orthogonal direction, the outer surface facing the machine direction curves toward the surface of the base portion, and the curved portion of the outer surface in the second shape is provided over more than 30% of the vertical range of the lower half of the stem portion, and when the peel strength of the hook-and-loop fastener when the hook-and-loop fastener and loop member that engage with each other are peeled along the machine direction and the orthogonal direction are defined as the MD peel strength and the CD peel strength, respectively, the stem portion has a shape in which the CD peel strength is greater than the MD peel strength because the second dimension is greater than the first dimension.

[0020] A hook-and-loop fastener of still another form provided by the present invention is a hook-and-loop fastener made of synthetic resin, which has a base portion and a plurality of engaging elements formed integrally with the base portion, each engaging element having a stem portion protruding from the surface of the base portion in the thickness direction of the base portion and an engaging head portion formed at the tip portion of the stem portion, and a cross section perpendicular to the thickness direction at least at the upper end portion of the stem portion has a circular or nearly circular shape, and the engaging head portion has a shape that expands from the tip portion of the stem portion to the entirety in the direction perpendicular to the thickness direction, UnderThe half includes a portion in which, in a second shape when the engaging element is viewed from a direction perpendicular to the machine direction, the outer surface facing the machine direction curves toward the surface of the base portion, and the curved portion of the outer surface in the second shape is provided over 30% or more of the vertical range of the lower half of the stem portion, and the connecting portion connecting to the base portion of the stem portion has an elliptical or approximately elliptical shape that is long in the machine direction, and the CD flexibility when the portion of the hook-and-loop fastener along the orthogonal direction is curved in the thickness direction is superior to the MD flexibility when the portion of the hook-and-loop fastener along the machine direction is curved in the thickness direction because the connecting portion has an elliptical or approximately elliptical shape that is long in the machine direction.

[0021] In the hook-and-loop fastener of the present invention, the multiple engaging elements are arranged in a row at a constant pitch along the machine direction to form an element row, the multiple element rows are arranged at constant intervals in the orthogonal direction, the engaging elements of each element row are arranged in a position shifted in the machine direction by half the pitch interval relative to the positions of the engaging elements of the element rows adjacent in the orthogonal direction, and it is preferable that the engaging elements are arranged in a position in the machine direction such that the formation range of the stem portion of each engaging element has a portion that overlaps with the formation range of the stem portion of the engaging elements in the element rows adjacent in the orthogonal direction. In the present invention, it is preferable that each engaging element has at least one claw portion protruding in the orthogonal direction from the outer peripheral edge of the engaging head portion. Furthermore, in the first shape of the engaging element when viewed from the machine direction, the outer surface of the stem portion facing the orthogonal direction is formed in a straight or approximately straight shape over almost the entire length from the upper end of the stem portion where it connects to the engaging head portion to the lower end of the stem portion where it connects to the base portion, and in the second shape, it is preferable that the portion of the stem portion where the outer surface facing the machine direction is formed in a straight or approximately straight shape is arranged in a range of more than 1 / 2 and less than 3 / 4 of the overall height dimension of the stem portion.

[0022] next, GrowthThe molding device is used for manufacturing a hook-and-loop fastener, and has a die wheel that rotates in one direction and a supply nozzle that supplies molten synthetic resin toward the die wheel, and has a base portion provided with a plurality of engaging elements, each of which has a stem portion that protrudes from the surface of the base portion in the thickness direction of the base portion and an engaging head portion formed at the tip of the stem portion. In this molding device, the die wheel has at least one cylindrical sleeve and a drive roller that rotates the sleeve, and the sleeve has a plurality of through holes that penetrate from the outer peripheral surface to the inner peripheral surface of the sleeve. The through holes have holes, and a plurality of the through holes are arranged in a row at a constant hole pitch interval along the machine direction to form a hole row, and the plurality of hole rows are arranged at constant intervals in an orthogonal direction perpendicular to the machine direction, and the through holes of each hole row are arranged at a position shifted in the machine direction by half the hole pitch interval with respect to the position of the through holes of the hole rows adjacent in the orthogonal direction, and the through holes are arranged at a position with respect to the machine direction where the formation range of each through hole has a portion that overlaps with the formation range of the through holes in the hole rows adjacent in the orthogonal direction. [Effects of the Invention]

[0023] According to the present invention, it is possible to provide a hook-and-loop fastener that exhibits different structures and / or properties between the machine direction and the cross direction. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a copy of a photograph taken from above of a portion of a hook-and-loop fastener according to an embodiment of the present invention. [Figure 2] 2 is a copy of a photograph of the engaging elements of the hook-and-loop fastener shown in FIG. 1 taken from above. [Figure 3] 2 is a copy of a photograph of the engaging elements of the hook-and-loop fastener shown in FIG. 1 taken from the machine direction. [Figure 4] 2 is a copy of a photograph of the engaging elements of the hook-and-loop fastener shown in FIG. 1 taken from an orthogonal direction. [Figure 5] FIG. 2 is a schematic diagram for explaining a manufacturing apparatus for manufacturing the hook-and-loop fastener shown in FIG. [Figure 6] 6 is a schematic view showing a part of an outer sleeve provided in a molding device of the manufacturing apparatus shown in FIG. 5. FIG. [Figure 7] FIG. 2 is a perspective view schematically showing a primary molded body molded in a primary molding step. [Figure 8] FIG. 1 is an explanatory diagram illustrating a peel strength test. [Figure 9] FIG. 10 is another explanatory view illustrating the peel strength test. [Figure 10] FIG. 2 is a schematic diagram showing a test device for measuring the flexibility of a hook-and-loop fastener. [Figure 11] 11 is a schematic diagram showing a state in which the hook-and-loop fastener is pressed by the testing device of FIG. 10. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0025] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. The present invention is not limited to the embodiments described below, and various modifications are possible as long as they have substantially the same configuration as the present invention and provide similar effects. For example, the length dimension (dimension in the machine direction MD) and width dimension (dimension in the cross direction CD) of the hook-and-loop fastener of the present invention are not particularly limited, and the hook-and-loop fastener can have any shape by cutting it, etc.

[0026] Fig. 1 is a copy of a photograph of a part of the hook-and-loop fastener according to this embodiment taken from above. Figs. 2 to 4 are copies of a photograph (plan view) of one engaging element of the hook-and-loop fastener according to this embodiment taken from above, a photograph (front view or back view) taken from the machine direction side, and a photograph (side view) taken from the orthogonal direction side, respectively.

[0027] In the following description, the front-rear direction is the length direction of the hook-and-loop fastener and the primary molded article which are molded in a long length. Also, the front-rear direction is the direction along the machine direction MD (first direction) in which the hook-and-loop fastener or the primary molded article is transported in the manufacturing process of the hook-and-loop fastener. The left-right direction is the width direction perpendicular to the length direction and along the flat upper surface (first surface) or lower surface (second surface) of the base part of the hook-and-loop fastener. In this case, the left-right direction and width direction are the direction (second direction) along the cross direction CD perpendicular to the machine direction MD. The vertical direction is the height direction (or thickness direction of the base) along a direction perpendicular to the flat upper or lower surface of the base, and is also a direction perpendicular to the front-rear direction and the left-right direction. In this case, the side on which the engaging element protrudes from the base is considered the upper side in the vertical direction, and the opposite side is considered the lower side.

[0028] The hook-and-loop fastener 10 of this embodiment is manufactured in a long shape in the machine direction MD of the manufacturing apparatus 50 using a manufacturing apparatus 50 having a molding apparatus 60, a heating and pressing apparatus 70, and a stretching apparatus 80 as shown in Figure 5, as described below.

[0029] The hook-and-loop fastener 10 is made of a thermoplastic resin such as polypropylene, polyester, nylon, polybutylene terephthalate, or a copolymer thereof. The material of the hook-and-loop fastener 10 is not particularly limited, and the hook-and-loop fastener 10 may be made of, for example, a biodegradable resin, a plant-derived resin, or a thermoplastic resin obtained by recycling.

[0030] As shown in Figs. 1 to 4, the hook-and-loop fastener 10 has a thin, flat base portion 11 and a plurality of mushroom-shaped engaging elements 20 that protrude from the upper surface of the base portion 11. The base portion 11 is formed long along the machine direction MD during the manufacture of the hook-and-loop fastener 10. The base portion 11 has a certain thickness that ensures appropriate strength and flexibility. The upper surface (first surface) of the base portion 11 and the lower surface (second surface) located on the opposite side of the upper surface are each flat or approximately flat and are formed parallel to each other.

[0031] Each engaging element 20 has a stem portion 21 protruding upward from the upper surface of the base portion 11, a disk-shaped engaging head 22 integrally formed at the upper end of the stem portion 21, and two tiny claw portions 23 protruding slightly outward from the outer peripheral edge of the engaging head 22 along the orthogonal direction CD.

[0032] Here, the shape of the stem portion 21 when the engaging element 20 is viewed in the machine direction MD is defined as a first shape 31 of the stem portion 21, and the shape of the stem portion 21 when the engaging element 20 is viewed in the orthogonal direction CD is defined as a second shape 32 of the stem portion 21. In this case, the stem portion 21 of each engaging element 20 (particularly the lower half of the stem portion 21) is subjected to a stretching process along the machine direction MD, which will be described later, in the manufacturing process of the hook-and-loop fastener 10, so that the first shape 31 of the stem portion 21 (see FIG. 3) and the second shape 32 of the stem portion 21 (see FIG. 4) are formed into shapes that are different from each other.

[0033] In the engaging element 20 of this embodiment, the first shape 31 and the second shape 32 of the stem portion 21 differ from each other mainly in the lower half of the stem portion 21, and the lower half of the first shape 31 of the stem portion 21 is formed to be thinner than the lower half of the second shape 32 of the stem portion 21. For this reason, the engaging element 20 is formed to be more likely to bend in the cross direction CD than in the machine direction MD, for example, when a force is applied from above the engaging element 20. Note that the upper and lower halves of the stem portion 21 refer to the part of the stem portion 21 that is farther from the base portion 11 than the center position in the height direction of the stem portion 21 and the part that is closer to the base portion 11 than the center position, respectively, when the stem portion 21 is divided at the center position of the stem portion 21.

[0034] To explain the shape of the stem portion 21 more specifically, in a front view ( FIG. 3 ) or a rear view of the engaging element 20 seen from the machine direction MD, the first shape 31 of the stem portion 21 is formed such that the outer surface 21a of the stem portion 21 facing the orthogonal direction CD of the stem portion 21 extends straight or along a line close to a straight line from the upper end of the stem portion 21 where it connects to the engaging head 22 to the lower end (connecting portion) of the stem portion 21 where it connects to the base portion 11. In the first shape 31 of the stem portion 21, an angle of approximately 95° is formed between the outer surface 21a of the stem portion 21 facing the orthogonal direction CD and the upper surface of the base portion 11. Note that the size of the angle between the outer surface of the stem portion 21 facing the orthogonal direction CD of the stem portion 21 and the upper surface of the base portion 11 is not limited to this.

[0035] In this embodiment, the first shape 31 may be formed so that the outer surface 21a of the stem portion 21 facing the orthogonal direction CD includes a curved portion that is concavely curved in the vertical direction, for example, at the lower end of the stem portion 21 close to the base portion 11. In this case, it is preferable that the straight or substantially straight portion of the outer surface 21a of the first shape 31 is provided over 50% or more, preferably 60% or more of the range of the lower half of the stem portion 21 in the vertical direction.

[0036] In the present invention, a "straight shape" that extends straight or a "substantially straight shape" that extends along a line that is nearly straight means that, when the outer peripheral surface of the stem portion 21, which is formed in a substantially cylindrical shape described below, is viewed in a direction such as the machine direction MD or the cross direction CD, the outer peripheral surface of the stem portion 21 does not include a curved portion that is significantly or clearly curved concavely in the vertical direction. For example, even if the outer surface 21a of the stem portion 21 facing the cross direction CD forms an angle greater than 95° (e.g., an angle of 100 to 110°) with respect to the upper surface of the base portion 11, the outer surface 21a is considered to be formed in a straight or substantially straight shape as long as it extends along a line that is straight or nearly straight.

[0037] On the other hand, in a side view ( FIG. 4 ) of the engaging element 20 seen from the orthogonal direction CD, the second shape 32 of the stem portion 21 is formed to include a portion where the outer surface 21 a of the stem portion 21 facing the machine direction MD is formed to be straight or approximately straight, and a curved portion where the outer surface 21 a extends while curving concavely in the up-down direction. In this second shape 32, the straight or approximately straight portion of the outer surface 21 a of the stem portion 21 facing the machine direction MD is provided mainly in the upper half of the stem portion 21, and is formed over a shorter range than the straight or approximately straight portion of the first shape 31 shown in FIG. 3. In the second shape 32, the curved portion where the outer surface 21 a of the stem portion 21 facing the machine direction MD is curved is provided mainly in the lower half of the stem portion 21. Furthermore, the curved portion of the outer surface 21a of the second shape 32 is preferably provided over 30% or more, and more preferably 40% or more of the range in the vertical direction in the lower half of the stem portion 21. When a curved portion is provided at the lower end of the first shape 31, for example, the curved portion of the outer surface 21a of the second shape 32 is formed over a longer range than the curved portion of the first shape 31.

[0038] The shape of the outer surface 21a facing the cross direction CD in the first shape 31 shown in Fig. 3 is similar to the shape of the upper half of the outer surface 21a facing the machine direction MD in the second shape 32 shown in Fig. 4. For example, in the upper half of the second shape 32 of the stem portion 21, the outer surface 21a facing the machine direction MD of the stem portion 21 is formed so as to form an angle of approximately 95° with respect to a direction parallel to the upper surface of the base portion 11. Furthermore, in the lower half of the second shape 32 of the stem portion 21, an angle of approximately 160° is formed between the outer surface 21a of the stem portion 21 arranged close to the base portion 11 and the upper surface of the base portion 11. In the second shape 32, the portion where the outer surface 21a of the stem portion 21 facing the machine direction MD is formed in a straight or approximately straight shape is arranged in a range of 1 / 2 or more and 3 / 4 or less of the overall height dimension of the stem portion 21 in the second shape 32 (the dimension in the vertical direction from the top surface of the base portion 11 to the top end of the stem portion 21).

[0039] When comparing the first shape 31 (Figure 3) and the second shape 32 (Figure 4) of the stem portion 21, the thickness of the lower half of the stem portion 21 showing the second shape 32 is changed significantly as the stem portion 21 approaches the base portion 11, as shown in Figure 4, compared to the lower half of the stem portion 21 showing the first shape 31.

[0040] In addition, in the first shape 31, the straight or approximately straight outer surface 21a of the stem portion 21 extends to the lower end where it connects to the base portion 11 of the stem portion 21, and a boundary portion is provided between this straight or approximately straight outer surface 21a and the upper surface (surface) of the base portion 11, which bends sharply at an angle close to 90° (approximately 95°).

[0041] In contrast, in the second shape 32, the outer surface 21a of the lower half of the stem portion 21 is gently curved, and the slope of the outer surface 21a of the stem portion 21 becomes gentler as it approaches the base portion 11. Therefore, the outer surface 21a of the stem portion 21 in the second shape 32 is formed so as to be smoothly continuous with the surface of the base portion 11.

[0042] In each engaging element 20, the upper half of the stem portion 21 is formed in a substantially cylindrical shape. Therefore, the outer peripheral surface of the upper half of the stem portion 21 is formed into a smoothly continuous curved surface all around, and the outer peripheral surface does not have any angular ridges or protrusions. Furthermore, the stem portion 21 is formed so that the cross section perpendicular to the vertical direction at the upper end of the stem portion 21 has a circular or nearly circular shape (a substantially circular shape).

[0043] The connecting portion of the stem portion 21 that connects to the base portion 11 (i.e., the lower end of the stem portion 21) is formed in an elliptical or approximately elliptical shape that is elongated in the machine direction MD so that the maximum dimension in the machine direction MD is greater than the maximum dimension in the cross direction CD. In the present invention, the term "approximately elliptical shape" means a shape close to an ellipse, and includes, for example, an oval shape.

[0044] Here, with respect to the connecting portion of stem portion 21, the length along the cross direction CD of the connecting portion when engaging element 20 is viewed in the machine direction MD is defined as a first dimension D1, and the length of the connecting portion in the machine direction MD when engaging element 20 is viewed in the cross direction CD is defined as a second dimension D2. In this case, stem portion 21 is formed such that the second dimension D2 of the connecting portion in second shape 32 is larger than the first dimension D1 of the connecting portion in first shape 31. The second dimension D2 of the connecting portion in second shape 32 is, for example, 1.5 to 2 times the first dimension D1 of the connecting portion in first shape 31.

[0045] In this embodiment, the multiple engaging elements 20 are regularly aligned in a staggered arrangement pattern on the upper surface of the base portion 11. Specifically, the engaging elements 20 are arranged at a constant pitch along the machine direction MD (front-to-back direction) to form an engaging element row 26. The multiple engaging element rows 26 are arranged at constant intervals in the cross direction CD (left-to-right direction). The engaging elements 20 of each engaging element row 26 are arranged at positions that are shifted in the machine direction MD by half the pitch interval with respect to the positions of the engaging elements 20 of the engaging element rows 26 adjacent to each other in the cross direction CD. As a result, the multiple engaging elements 20 are arranged alternately or in a zigzag pattern between the engaging element rows 26 adjacent to each other in the cross direction CD.

[0046] 1, the multiple engaging elements 20 are arranged in a position in the machine direction MD such that the forming area 27 of the stem portion 21 of each engaging element 20 has a portion that overlaps with the forming area 27 of the engaging elements 20 of the engaging element row 26 adjacent in the cross direction CD. In other words, the edge on one side (e.g., the front side) in the machine direction MD of the stem portion 21 of each engaging element 20 is located between the edge on one side (e.g., the front side) and the edge on the other side (e.g., the rear side) in the machine direction MD of the stem portion 21 of the engaging element 20 of the engaging element row 26 adjacent in the cross direction CD.

[0047] In this embodiment, the hook-and-loop fastener 10 has at least one of the following structures: (1) the second shape 32 of the stem portion 21 when the engaging element 20 is viewed in the orthogonal direction CD includes a portion that curves the outer surface 21a of the stem portion 21 and is formed thicker than the first shape 31 of the stem portion 21 when viewed in the machine direction MD; (2) the connecting portion that connects the stem portion 21 to the base portion 11 is formed in an elliptical or approximately elliptical shape with the second dimension D2 in the machine direction MD larger than the first dimension D1 in the orthogonal direction CD; and (3) in the staggered arrangement of the engaging elements 20, the formation range 27 of the stem portion 21 of each engaging element 20 in the machine direction MD overlaps with the formation range 27 of the engaging element 20 in the engaging element row 26 adjacent in the orthogonal direction CD. This effectively increases the strength of the base portion 11 in the machine direction MD. Therefore, for example, in the stretching process for forming the base portion 11 in the manufacturing process of the hook-and-loop fastener 10, when the base portion 11 is stretched in the machine direction MD, defects such as breakage can be made less likely to occur in the base portion 11.

[0048] In the engaging element 20 of this embodiment, the engaging head 22 is formed relatively thin in the vertical direction and has a shape that expands from the tip of the stem portion 21 to the entire direction perpendicular to the vertical direction (i.e., the direction parallel to the upper surface of the base portion 11). When the engaging element 20 is viewed from above, the engaging head 22 has an elliptical or approximately elliptical shape that is elongated in the perpendicular direction CD as shown in FIG. 2. This disk-shaped engaging head 22 is formed to protrude radially outward from the upper end of the stem portion 21 (in other words, the boundary between the stem portion 21 and the engaging head 22). Note that the shape of the engaging head is not limited to a disk that is elliptical or approximately elliptical when viewed from above. As long as it expands from the tip of the stem portion 21 in a direction parallel to the surface of the base portion 11, it may have a shape that is a perfect circle, a shape close to a perfect circle, or a shape close to a polygon such as a rectangle when viewed from above.

[0049] Each engaging element 20 is provided with a pair of left and right tiny claws 23 that protrude in opposite directions from the outer periphery of the engaging head 22 along the cross direction CD. In this case, the left and right claws 23 are arranged at the left and right ends of the engaging head 22, which is long in the cross direction CD. In addition, the outer periphery of the engaging head 22 has a non-forming region where no claws 23 are provided, and in this embodiment, the non-forming region of the engaging head 22 where no claws 23 are formed is arranged facing the machine direction MD.

[0050] 3, each of the left and right claw portions 23 has a shape that hangs diagonally downward from the outer peripheral edge of the engaging head 22 toward the tip in the protruding direction so as to approach the base portion 11. In addition, in a plan view of the engaging element 20 seen from above, each of the claw portions 23 has a base end that connects to the engaging head 22 of the claw portion 23 formed to a very small size that is smaller than the maximum dimension of the engaging head 22 in the machine direction MD, preferably 2 / 3 or less of that maximum dimension.

[0051] By providing such minute claw portions 23 on each engaging element 20, when the loop member is engaged with the hook-and-loop fastener 10, the loop of the loop member engaged with the engaging element 20 can be easily caught on the claw portions 23, making it more difficult for the loop to come off the engaging element 20. Furthermore, by forming the claw portions 23 in a minute size relative to the engaging heads 22, the effect of the placement of the claw portions 23 on the feel or sensation on the upper surface of the hook-and-loop fastener 10 can be kept small.

[0052] In the present invention, the shape and size of the engaging head are not particularly limited as long as the engaging head is formed in a shape that expands from the upper end of the stem in a direction perpendicular to the up-down direction. Furthermore, the shape of the claws, the number of claws provided, and the direction in which the claws protrude from the engaging head are also not particularly limited. The engaging element may be formed without providing a claw. A single hook-and-loop fastener may be provided with multiple types of engaging elements that are different in shape.

[0053] Next, a manufacturing apparatus 50 for manufacturing the hook-and-loop fastener 10 of the present embodiment will be described with reference to FIGS. The manufacturing apparatus 50 of this embodiment has a molding device 60 that performs primary molding, a heat pressing device 70 that performs secondary molding on the primary molded body 40 (see FIG. 7) molded by the molding device 60 to form a secondary molded body (pre-fastener body), and a stretching device 80 that performs stretching on the resulting secondary molded body. In the present invention, the pre-fastener body means a molded body or member before being stretched when the hook-and-loop fastener 10 is manufactured by stretching.

[0054] The molding device 60 has a die wheel 61 that is driven to rotate in one direction (counterclockwise in the drawing), a supply nozzle 65 that is arranged opposite the peripheral surface of the die wheel 61 and continuously supplies molten synthetic resin material, and a pickup roller 66 that is arranged downstream of the supply nozzle 65 in the direction of rotation of the die wheel 61.

[0055] The die wheel 61 includes a cylindrical outer sleeve (outer cylinder) 62 that serves as a die, a cylindrical inner sleeve (inner cylinder) 63 that is disposed in close contact with the inside of the outer sleeve 62, and a drive roller 64 that rotates the outer sleeve 62 and the inner sleeve 63 in one direction. A cooling jacket (not shown) that circulates a cooling liquid is provided inside the drive roller 64.

[0056] The outer sleeve 62 has a plurality of through holes 62a that penetrate from the outer peripheral surface to the inner peripheral surface of the outer sleeve 62, and serve as cavities for molding a primary stem portion 43 (described later) of the primary molded body 40. Each through hole 62a has a generally truncated conical shape in which the circle on the outer peripheral surface of the outer sleeve 62 is larger than the circle on the inner peripheral surface of the outer sleeve 62.

[0057] The positions of the through holes 62a formed in the outer sleeve 62 correspond to the positions where the engaging elements 20 will be disposed in the secondary molded body to be produced. Specifically, the through holes 62a are regularly aligned in a staggered pattern on the outer sleeve 62, as shown in FIG. 6 . The through holes 62a are arranged at a constant pitch in the machine direction MD to form hole rows 62b. The hole rows 62b are also arranged at a constant pitch in the cross direction CD. The through holes 62a in each hole row 62b are shifted in position by half the pitch in the machine direction MD with respect to the positions of the through holes 62a in the hole rows 62b adjacent to each other in the cross direction CD. As a result, the through holes 62a are arranged alternately or in a zigzag pattern between adjacent hole rows 62b in the left-right direction.

[0058] Furthermore, the multiple through holes 62a are arranged in positions in the machine direction MD such that the formation range 62c of each through hole 62a overlaps with the formation range 62c of the through holes 62a of the hole row 62b adjacent to it in the cross direction CD. By forming the multiple through holes 62a in the outer sleeve 62 in such a positional relationship, when the hook-and-loop fastener 10 is manufactured, the multiple engaging elements 20 can be stably arranged between the engaging element rows 26 adjacent to each other in the cross direction CD so that the formation ranges 27 of the engaging elements 20 overlap with each other.

[0059] A plurality of grooves are formed in the outer peripheral surface of the inner sleeve 63. Each groove is linearly recessed along the orthogonal direction CD parallel to the central axis of the inner sleeve 63 and is sized to allow the flow of molten synthetic resin. The grooves are formed at regular intervals along the circumferential direction (machine direction MD) of the inner sleeve 63. Furthermore, at least some of the grooves of the inner sleeve 63 are arranged so as to intersect with the outer peripheral edges of the through holes 62a formed in the inner peripheral surface of the outer sleeve 62 when the die wheel 61 is assembled.

[0060] In the present invention, the shape of the recesses provided in the outer peripheral surface of the inner sleeve is not limited to the linear grooves of the present embodiment. In the present invention, for example, a zigzag groove or a recess formed by recessing the outer peripheral surface of the inner sleeve into a three-dimensional shape such as a rectangular parallelepiped may be provided in the outer peripheral surface of the inner sleeve. Furthermore, instead of having two sleeves, an outer and an inner, as in the present embodiment, the die wheel may be formed with, for example, a single sleeve having a plurality of through holes penetrating from the outer peripheral surface to the inner peripheral surface and a plurality of grooves provided in the inner peripheral surface.

[0061] The pickup roller 66 has a pair of upper and lower clamping rollers 67 and 68 that clamp and pull the primary molded body 40 formed on the outer circumferential surface of the die wheel 61. The outer circumferential surfaces of the upper and lower clamping rollers 67 and 68 are each provided with a surface layer (not shown) made of an elastomer such as polyurethane elastomer.

[0062] The heating and pressing device 70 has a pair of upper and lower pressing rollers (calendar rollers) 71, 72 arranged downstream of the pickup roller 66. The upper pressing roller 71 and the lower pressing roller 72 are arranged facing each other with a predetermined gap between them. The gap between the upper pressing roller 71 and the lower pressing roller 72 can be adjusted by a height adjustment means (not shown).

[0063] The upper pressure roller 71 is provided with an internal heating source (not shown), and the surface temperature of the upper pressure roller 71 is set to a temperature that can soften the synthetic resin that forms the hook-and-loop fastener 10 (primary molded body 40). In the present invention, the structure of the heating and pressing device is not particularly limited as long as it can press at least a part of the primary molded body 40 to form engaging elements, as will be described later.

[0064] The stretching device 80 is installed downstream of the heating and pressing device 70 in order to at least stretch the prefastener body (secondary formed body) formed by the heating and pressing device 70. Although not specifically shown, the stretching device 80 has a supply section that introduces the prefastener body into the stretching device 80, a discharge section that sends out the stretched hook-and-loop fastener 10 downstream, and a plurality of rotating rollers that are arranged between the supply section and the discharge section along the transport path of the material to be processed (i.e., the prefastener body or hook-and-loop fastener 10).

[0065] Each of the rotating rollers is configured to be able to convey the workpiece downstream at a speed corresponding to the rotation speed by rotating while contacting the workpiece, and at least some of the rotating rollers are configured to be able to heat the workpiece to a predetermined heating temperature by bringing the workpiece into contact with the outer circumferential surface of the roller.

[0066] The rotating rollers of the stretching device 80 include a heating roller that heats the pre-fastener body, a stretching roller that stretches the pre-fastener body between the heating roller, and a relaxation roller disposed downstream of the stretching roller. In this case, the heating roller, stretching roller, and relaxation roller are installed so as to snake up and down the conveyance path for the workpiece.

[0067] The heating roller rotates at a constant rotational speed to transport the pre-fastener body and heats it by bringing it into contact with the roller surface. The heating roller is also provided with a support roller (nip roller) disposed opposite the heating roller, and the heating roller and support roller rotate at a constant speed while sandwiching and holding the pre-fastener body from above and below. The heating roller heats the pre-fastener body to a temperature at which it can be stretched before stretching. In this embodiment, the means and method for performing the heat treatment before stretching are not particularly limited.

[0068] The stretching roller is controlled to rotate at a rotational speed faster than that of the heating roller while contacting the workpiece with the roller surface. For example, in this embodiment, the rotational speed of the stretching roller is set to be 110% or more and 200% or less of the rotational speed of the heating roller. The heating temperature of the stretching roller is set to be equal to or higher than the heating temperature of the heating roller and lower than the melting point of the synthetic resin forming the hook-and-loop fastener 10. This allows the pre-fastener body to be stretched between the heating roller and the stretching roller. This stretching stretches a temporary base portion 41 of the pre-fastener body, which will be described later, along the machine direction MD, forming the base portion 11 of the hook-and-loop fastener 10.

[0069] The relaxation rollers are controlled to rotate at a slower rotation speed than the stretching rollers while the workpiece is in contact with the roller surface. The heating temperature of the relaxation rollers is set lower than the melting point of the synthetic resin that forms the hook-and-loop fastener 10. This reduces the tension applied to the hook-and-loop fastener 10 between the stretching rollers and the relaxation rollers, making it possible to stabilize the shape and dimensions of the hook-and-loop fastener 10.

[0070] The above-described structure of the stretching device 80 of this embodiment is merely an example. In the present invention, the structure of the stretching device is not particularly limited as long as it is disposed at least downstream of the molding device and is formed so as to be able to stretch a molded body such as a prefastener body sent out from the primary molding device or the hot pressing device along the machine direction MD.

[0071] Next, a method for manufacturing the hook-and-loop fastener 10 using the above-described manufacturing apparatus 50 will be described. The manufacturing method of this embodiment includes a primary molding step in which a primary molding device 60 is used to mold a primary molded body 40 as shown in Figure 7, a secondary molding step in which a pre-fastener body (not shown) having engaging elements 20 is molded by deforming a portion of the primary molded body 40 using a heating and pressing device 70, and a stretching step in which a stretching process is performed on the pre-fastener body along the machine direction MD using a stretching device 80 to form a hook-and-loop fastener 10.

[0072] In the primary molding step, molten synthetic resin is continuously supplied from a supply nozzle 65 toward the outer peripheral surface of the die wheel 61. As a result, temporary base portions 41 are continuously molded between the supply nozzle 65 and the die wheel 61. Furthermore, a plurality of primary elements (temporary elements) 42 are molded integrally with the temporary base portions 41 by means of through holes 62a provided in the outer sleeve 62 of the die wheel 61 and recessed grooves provided in the inner sleeve 63. Therefore, a primary molded body 40 shown in FIG. 7 is molded by this primary molding step.

[0073] The primary molded body 40 formed at this time has a flat plate-shaped temporary base portion 41 and a plurality of primary elements 42 protruding from the upper surface of the temporary base portion 41. The temporary base portion 41 is formed to be thicker than the base portion 11 of the hook-and-loop fastener 10 to be manufactured.

[0074] The primary elements 42 are deformed into the engaging elements 20 by being subjected to secondary molding (press molding) in the secondary molding process. A plurality of primary elements 42 are provided on the temporary base 41 in a staggered arrangement pattern. Each primary element 42 has a truncated cone-shaped primary stem 43 protruding from the temporary base 41, a rod-shaped rib 44 partially bulging upward from the upper surface of the primary stem 43, and two protrusions (primary claws) 45 formed integrally with the rib 44 and protruding from both ends of the rib 44. The rib 44 and the left and right protrusions 45 are formed along the orthogonal direction CD. Furthermore, the left and right protrusions 45 protrude outward beyond the upper end surface of the primary stem 43.

[0075] Furthermore, since the multiple primary elements 42 are provided corresponding to the formation positions of the multiple through holes 62a provided in the outer sleeve 62, the formation areas of the primary stem portions 43 of each primary element 42 in the machine direction MD are formed so as to overlap with each other between adjacent element rows in the cross direction CD. Note that the primary element 42 may have two protrusions (primary claw portions) 45 that partially bulge upward from the top surface of the primary stem portion 43. In this case, four tiny claw portions 23 that protrude outward from the outer periphery of the engaging head 22 are formed in the secondary molding process described below.

[0076] In the primary molding step of this embodiment, the molten synthetic resin is supported on the outer circumferential surface of the die wheel 61 and rotates halfway while being cooled, thereby molding the above-mentioned primary molded body 40. Thereafter, the primary molded body 40 is continuously peeled off from the outer circumferential surface of the die wheel 61 by a pickup roller 66.

[0077] Next, the primary molded body 40 peeled off from the die wheel 61 is transported toward the heating and pressing device 70 where the secondary molding process is performed, and is introduced between the upper pressing roller 71 and the lower pressing roller 72 of the heating and pressing device 70.

[0078] In the secondary molding process using the heating and pressing device 70, the temporary base portion 41 of the primary molded body 40 is supported from below by the lower pressure roller 72. At least the upper end portion of each primary element 42 of the primary molded body 40 is heated and softened by the upper pressure roller 71, and is pressed from above. As a result, a secondary element (not shown) is molded from the primary element 42, and a pre-fastener body is produced in which a plurality of secondary elements are integrally formed on the temporary base portion 41.

[0079] Although not shown, the secondary element formed in this secondary forming process has a secondary stem portion having an approximately truncated cone shape rising from the temporary base portion 41, an engaging head 22 formed integrally with the upper end of the secondary stem portion, and two tiny claw portions 23 protruding outward from the outer peripheral edge of the engaging head 22.

[0080] In this case, the secondary stem portion of each secondary element has a circular or nearly circular cross section perpendicular to the up-down direction, and the diameter of the cross section gradually decreases with increasing distance from the temporary base portion 41. The shape of the secondary stem portion when the secondary element is viewed in the machine direction MD and the shape of the secondary stem portion when the secondary element is viewed in the orthogonal direction CD are formed to be the same or nearly the same. The engaging head portion 22 and the claw portion 23 provided on each secondary element are formed to be substantially the same shape and size as the engaging head portion 22 and the claw portion 23 of the engaging element 20 shown in Figures 1 to 4.

[0081] After the secondary forming process, the prefastener body sent out from the heating and pressing device 70 is transported to the stretching device 80 (see FIG. 5). In the stretching device 80, the prefastener body is introduced into the device from a supply section (not shown), and the prefastener body is subjected to a heating treatment using a heating roller (heating step), a stretching process between the heating roller and a stretching roller (stretching step), and a relaxation process after the stretching process (relaxation step) in that order.

[0082] In the heat treatment in the stretching device 80, the pre-fastener body is brought into contact with the roller surface of the heating roller, thereby heating the pre-fastener body to a temperature at which it can be stretched. After the prefastener body passes through the heating rollers, it is stretched (uniaxially stretched) between the heating rollers and stretching rollers that rotate at a faster speed than the heating rollers to stretch the prefastener body in the machine direction MD. This stretching stretches the temporary base portion 41 of the prefastener body in the machine direction MD to form the base portion 11 of the hook-and-loop fastener 10. The thickness between the upper and lower surfaces of the base portion 11 obtained after this stretching is thinner than the thickness between the upper and lower surfaces of the temporary base portion 41 after the secondary molding step.

[0083] Furthermore, in the stretching process of this embodiment, when the temporary base portion 41 is stretched, the processing conditions are such that the lower end portions of the secondary stem portions of the secondary element are stretched in the machine direction MD together with the temporary base portion 41. In this case, the processing conditions for the stretching process include, for example, at least one of the heating temperature of the prefastener body, the rotation speed of the heating rollers, the rotation speed of the stretching rollers, etc.

[0084] By stretching the lower end of the secondary stem portion through this stretching process, the substantially truncated cone-shaped secondary stem portion can be elongated in the machine direction MD, and transformed into the stem portion 21 having an elliptical or substantially elliptical shape with the connecting portion with the base portion 11 being elongated in the machine direction MD. Also, the stem portion 21 can be formed into the above-mentioned first shape 31 and second shape 32 which are different from each other. As a result, the engaging element 20 having the shape shown in Figures 1 to 4 is formed from the secondary element formed in the secondary molding step.

[0085] Furthermore, this stretching process can make it difficult for breakage to occur along the machine direction MD in the base portion 11. The reason why breakage is difficult to occur is not clear, but one possible reason is that in this embodiment, both in the secondary elements in the pre-fastener body and in the engaging elements 20 of the manufactured hook-and-loop fastener 10, the formation areas 27 of the secondary stem portions or stem portions 21 overlap each other between adjacent element rows in the orthogonal direction CD.

[0086] For example, if the portions of the temporary base portion where secondary stem portions are not provided or the portions of the base portion 11 where stem portions 21 are not provided are continuously formed along the cross direction CD, the strength of the temporary base portion or base portion 11 may be locally reduced in the portions where secondary stem portions or stem portions 21 are not provided, and such portions of reduced strength may be formed in the temporary base portion or base portion 11 at regular intervals in the machine direction MD. In contrast, in this embodiment, the formation areas 27 of the secondary stem portions or stem portions 21 overlap each other between adjacent element rows in the cross direction CD, thereby preventing localized reductions in the strength of the temporary base portion or base portion 11. This is thought to make it less likely for the base portion 11 to break in the machine direction MD during stretching.

[0087] By carrying out the above-described stretching process, the hook-and-loop fastener 10 of this embodiment can be obtained from the pre-fastener body. Note that the stretching method, means, conditions, etc. are not particularly limited as long as it is possible to stretch the temporary base portion 41 of the pre-fastener body in the machine direction MD to thin it, and to form the stem portion 21 that is long in the machine direction MD from the substantially truncated cone-shaped secondary stem portion.

[0088] After the above-mentioned stretching process, a relaxation process is performed on the hook-and-loop fastener 10 having the base portion 11 and the engaging elements 20. In this relaxation process, the hook-and-loop fastener 10 is transported between a stretching roller and a relaxation roller that rotates at a slower rotation speed than the stretching roller in a state where the tension applied to the hook-and-loop fastener 10 is weakened. This makes it possible to stabilize the shape of the hook-and-loop fastener 10.

[0089] Thereafter, the hook-and-loop fastener 10 that has passed through the relaxation roller is sent out from the discharge section of the stretching device 80. The hook-and-loop fastener 10 that has been discharged from the stretching device 80 is wound up in a roll on, for example, a recovery roller and recovered. The hook-and-loop fastener 10 may also be transported from the stretching device 80 toward a cutting section (not shown), where it is cut into a predetermined width and / or length, and then recovered.

[0090] The surface fastener 10 of this embodiment shown in FIGS. 1 to 4 is manufactured by carrying out the manufacturing method including the above-described primary molding step, secondary molding step, and stretching step.

[0091] In the manufactured hook-and-loop fastener 10 of this embodiment, the stem portion 21 of each engaging element 20 has a structure in which the first shape 31 when the engaging element 20 is viewed from the machine direction MD and the second shape 32 when the engaging element 20 is viewed from the orthogonal direction CD are different from each other (i.e., the difference between the machine direction MD and the orthogonal direction CD), as shown in Figures 3 and 4.

[0092] In particular, in this embodiment, the connecting portion of the stem portion 21 that connects to the base portion 11 is formed in the shape of an ellipse or a nearly ellipse that is long in the machine direction MD, and the hook-and-loop fastener 10 is formed so that the forming areas 27 of the stem portions 21 in the machine direction MD overlap each other between adjacent engaging element rows 26 in the orthogonal direction CD. As a result, as described above, even if the base portion 11 is formed thin by the above-mentioned stretching process, when force is applied to the base portion 11 of the hook-and-loop fastener 10 (for example, during the stretching process in the manufacturing process of the hook-and-loop fastener 10), it is possible to make it difficult for the base portion 11 to break along the machine direction MD.

[0093] Furthermore, in the hook-and-loop fastener 10 of this embodiment, each engaging element 20 has a different structure in the machine direction MD and the cross direction CD, and as will be described below, it can exhibit different properties in the machine direction MD and the cross direction CD.

[0094] For example, regarding the peel strength of the hook-and-loop fastener 10 from the loop member, the strength when the hook-and-loop fastener 10 is peeled along the machine direction MD is defined as the MD peel strength, and the strength when the hook-and-loop fastener 10 is peeled along the cross direction CD is defined as the CD peel strength. In this case, the hook-and-loop fastener 10 of this embodiment has a structure with directional properties, and as will be explained below, has the property that the CD peel strength is greater than the MD peel strength.

[0095] Here, a method for measuring the CD peel strength and MD peel strength of the surface fastener 10 will be described with reference to FIGS. When measuring the CD peel strength of the hook-and-loop fastener 10, first, a long, thin piece 91 whose dimension in the machine direction MD is longer than its dimension in the cross direction CD is cut out of the hook-and-loop fastener 10, as shown in Fig. 8, for example. Then, a first test piece 93 on the hook-and-loop fastener 10 side is prepared by adhering the cut piece 91 to a support member 92. A loop member formed with a predetermined basis weight is cut into a predetermined shape and size to prepare a second test piece 94 to be engaged with the cut piece 91 (hook-and-loop fastener 10) of the first test piece 93.

[0096] Next, the hook-and-loop fastener 10 attached to the first test piece 93 is engaged with the second test piece 94, and the second test piece 94 is folded back into a U-shape as shown in FIG. 9. The first test piece 93 and the second test piece 94 are then each gripped with a pair of clampers (not shown). The clampers gripping the first test piece 93 and the clamper gripping the second test piece 94 are then moved away from each other at a constant speed. This allows a load to be gradually applied to the engaged first test piece 93 and the second test piece 94, as indicated by the arrows in FIG. 9. The average load over a 50 mm period from the start of the load application is then calculated using the integral method (note that the analysis is performed between 3 mm from the engagement point and 99% of the 50 mm). The CD peel strength (N / cm) of the hook-and-loop fastener 10 is measured by dividing this calculated value by the effective width (cm) of the hook-and-loop fastener 10.

[0097] On the other hand, when measuring the MD peel strength of the hook-and-loop fastener 10, a long, thin piece is cut from the hook-and-loop fastener 10, with the dimension in the cross direction CD being longer than the dimension in the machine direction MD. The cut piece of the hook-and-loop fastener is then attached to a support member to prepare a first test piece on the hook-and-loop fastener 10 side. Thereafter, a second test piece is prepared in the same manner as when measuring the CD peel strength. The obtained first and second test pieces are used to perform the same measurement as when measuring the CD peel strength, thereby measuring the MD peel strength (N / cm) of the hook-and-loop fastener 10.

[0098] In the hook and loop fastener 10 of this embodiment, the claw portions 23 of the engaging elements 20 protrude along the orthogonal direction CD, making it easier to hook the loops of the loop members onto the claw portions 23 of the engaging elements 20 when engaging the hook and loop fastener 10 with the loop members along the orthogonal direction CD. Furthermore, the first shape 31 of the stem portion 21 when the engaging elements 20 are viewed in the machine direction MD is thinner than the second shape 32 of the stem portion 21 when the engaging elements 20 are viewed in the orthogonal direction CD. Therefore, as described above, each engaging element 20 is formed to be more easily bent in the orthogonal direction CD than in the machine direction MD. Because the stem portion 21 of the engaging elements 20 is thus more easily bent in the orthogonal direction CD, when engaging the hook and loop fastener 10 with the loop members along the orthogonal direction CD, the engaging elements 20 can be inserted deeper between the loops of the loop members by utilizing the bending of the stem portion 21 compared to, for example, when engaging the hook and loop fastener 10 with the loop members along the orthogonal direction CD. This allows each engaging element 20 to be more firmly engaged with the loop members.

[0099] Therefore, when the MD peel strength and the CD peel strength are measured and compared, the hook-and-loop fastener 10 of this embodiment has the property that the CD peel strength is higher than the MD peel strength. For example, in the case of the hook-and-loop fastener 10 of this embodiment, the CD peel strength and the MD peel strength were each measured multiple times and the average values were calculated, resulting in a CD peel strength of 0.53 N / cm and a MD peel strength of 0.02 N / cm. This confirmed that the CD peel strength was 10 times or more greater than the MD peel strength. In this embodiment, even though each engaging element 20 has a different structure in the machine direction MD and the cross direction CD, no directional difference was observed in the shear strength of the hook-and-loop fastener 10.

[0100] When the hook-and-loop fastener 10 of this embodiment, which has a higher CD peel strength than its MD peel strength, is used in, for example, a disposable diaper, it is preferable to attach the hook-and-loop fastener 10 to the disposable diaper in an orientation in which engagement with and release from the loop member are performed along the orthogonal direction CD of the hook-and-loop fastener 10 (i.e., the orientation shown in FIG. 8). In this way, when the hook-and-loop fastener 10 is engaged with the loop member of the disposable diaper, the high CD peel strength of the hook-and-loop fastener 10 stably maintains the engaged state between the hook-and-loop fastener 10 and the loop member, and the hook-and-loop fastener 10 does not easily peel off from the loop member. As a result, the attached state of the diaper can be stably maintained by the engagement between the hook-and-loop fastener 10 and the loop member.

[0101] Furthermore, for example, when it is desired to readjust the attachment state of a disposable diaper, the hook-and-loop fastener 10 may be pulled strongly to peel it off from the loop member, and then the hook-and-loop fastener 10 may be re-engaged to the loop member at an appropriate position. In such a case, in the hook-and-loop fastener 10 of this embodiment, the engaging elements 20 are formed to be easily flexible in the orthogonal direction CD as described above. Therefore, when the hook-and-loop fastener 10 is peeled off from the loop member with a strong force, the bending of the stem portion 21 in the orthogonal direction CD can be utilized to facilitate smooth release of the loop of the loop member from the engaging elements 20. As a result, the loop of the loop member is less likely to be broken or damaged during peeling, enabling stable repeated engagement and separation of the hook-and-loop fastener 10 and the loop member. Furthermore, even when engagement and separation are repeated, the engagement strength between the hook-and-loop fastener 10 and the loop member is less likely to decrease.

[0102] Furthermore, because the engaging elements 20 are formed to be easily flexible in the orthogonal direction CD as described above, when the hook-and-loop fastener 10 is pulled strongly to peel it off from the loop member, the bending of the stem portions 21 as described above allows the loop of the loop member to be smoothly released from the engaging elements 20. Therefore, even if the tear strength of the base portion 11 in the orthogonal direction CD has decreased due to stretching, when a large force is applied to the hook-and-loop fastener 10 engaged with the loop member, the engagement between the engaging elements 20 and the loop member is released, thereby preventing tearing of the base portion 11 in the orthogonal direction CD.

[0103] In the hook-and-loop fastener 10 of this embodiment, each engaging element 20 has a different structure in the machine direction MD and the orthogonal direction CD, and as a result, as described below, the CD flexibility when the portion of the hook-and-loop fastener 10 along the orthogonal direction CD is bent in the vertical direction is higher than the MD flexibility when the portion of the hook-and-loop fastener 10 along the machine direction MD is bent in the vertical direction.

[0104] Here, a method for measuring the MD flexibility and CD flexibility of the surface fastener 10 will be described with reference to FIGS. Fig. 10 shows the state before the flexibility test device is activated, and Fig. 11 shows the state after the flexibility test device is activated and pressure is applied to the surface fastener 10.

[0105] When measuring MD flexibility, the hook-and-loop fastener 10 is cut to prepare a long test piece 101 in which the machine direction MD is longer than the cross direction CD. When measuring CD flexibility, the hook-and-loop fastener 10 is cut to prepare a long test piece 101 in which the cross direction CD is longer than the machine direction MD.

[0106] The obtained test piece 101 is bent near the center in the longitudinal direction of the test piece 101 so as to bend into a loop shape in the front-to-back direction of the base portion 11, thereby forming a loop portion 102 on the test piece 101. At this time, the test piece 101 is bent so that the engaging elements 20 of the hook-and-loop fastener 10 are disposed on the inner periphery of the loop portion 102. Furthermore, both longitudinal ends of the test piece 101 on which the loop portion 102 has been formed are overlapped to form an overlapping portion 103. In this case, the test piece 101 is bent so that the length of the loop portion 102 is 100 mm and the length of the overlapping portion 103 is 20 mm or more, for example.

[0107] The flexibility testing device has a movable member 104 that moves up and down, a pressure element 106 attached to the movable member 104 and applying pressure to the loop portion 102 of the test piece 101, a clamp 107 that fixes the overlap portion 103 of the test piece 101, and a load cell 105 attached to the clamp 107 that converts the load into an electrical signal.

[0108] The clamp 107 supports the test piece 101 by clamping and holding the overlapping portion 103 of the test piece 101 so that the loop portion 102 of the test piece 101 protrudes toward the pressure element 106. In this state, the moving member 104 is moved upward. As the moving member 104 moves upward, the pressure element 106 also moves upward, and as shown in FIG. 11 , the pressure element 106 presses the loop portion 102 of the test piece 101. After the moving member 104 is moved upward to a predetermined position, the maximum load within the movement range is measured using the load cell 105. This maximum load measurement was performed multiple times for the test piece 101 with a long length in the machine direction MD and the test piece 101 with a long length in the cross direction CD, and the average values were calculated as the MD flexibility and the CD flexibility. Note that the smaller this average value, the more flexible the hook-and-loop fastener 10 is.

[0109] 2, in the hook-and-loop fastener 10 of this embodiment, the engaging head 22 of each engaging element 20 is formed in an elliptical or approximately elliptical shape that is elongated in the cross direction CD, but the connecting portion of the stem portion 21 that connects to the base portion 11 has an elliptical or approximately elliptical shape that is elongated in the machine direction MD. Furthermore, the forming areas 27 of the stem portions 21 of each engaging element 20 in the machine direction MD overlap between adjacent engaging element rows 26 in the cross direction CD. Therefore, when the MD flexibility and the CD flexibility are measured and compared, the CD flexibility is smaller than the MD flexibility. In other words, the hook-and-loop fastener 10 has the property of being more flexible in the cross direction CD than in the machine direction MD. For example, when the CD flexibility and MD flexibility of the hook-and-loop fastener 10 of this embodiment were measured, it was confirmed that the MD flexibility was 0.07 and the CD flexibility was 0.05, which is smaller than the MD flexibility.

[0110] When the hook-and-loop fastener 10 of this embodiment, which has superior CD flexibility to MD flexibility, is used in, for example, a disposable diaper, it is preferable to attach the hook-and-loop fastener 10 to the disposable diaper in an orientation such that engagement with and release from the loop members occurs along the cross direction CD of the hook-and-loop fastener 10. This makes it easier for the hook-and-loop fastener 10 to bend in the front-to-back direction (up-and-down direction) of the base portion 11 when engaging the hook-and-loop fastener 10 with the loop members of the disposable diaper or when releasing the hook-and-loop fastener 10 from the loop members, improving the ease of handling of the hook-and-loop fastener 10 and making it easier to attach and remove the disposable diaper.

[0111] Furthermore, even if the tear strength of the base portion 11 in the cross direction CD is reduced by stretching, when a large force is applied to the base portion 11, the base portion 11 is bent in the front-to-back direction (up-and-down direction), so it is possible to prevent tearing of the base portion 11 in the cross direction CD. Also, because the MD flexibility value of the hook-and-loop fastener 10 is large, it is possible to prevent the hook-and-loop fastener 10 from rolling up in the MD direction due to friction between the clothes and the disposable diaper, for example, when picking up a baby or taking off clothes.

[0112] The secondary molded body in the above-described embodiment is produced by performing a primary molding step using the molding device 60 and a secondary molding step using the hot pressing device 70. However, in the present invention, the method and means for molding the molded body to be stretched are not particularly limited. In the present invention, for example, the molded body to be stretched may be directly molded by performing a molding step using a molding device provided with a cavity capable of molding an engaging element having a stem portion and an engaging head, without performing a secondary molding step that causes thermal deformation as in the above-described embodiment. [Explanation of symbols]

[0113] 10 hook-and-loop fasteners 11 Base 20 Engagement element 21 Stem 21a Outer surface of stem 22 Engagement head 23 Claw 26 Engagement element row 27 Formation Range 31 1st shape 32 Second shape 40 Primary molded body 41 Temporary base 42 Primary element (provisional element) 43 Primary stem 44 Rib section 45 Projection part (primary claw part) 50 Manufacturing equipment 60 Molding equipment 61 Die Wheel 62 Outer sleeve (outer cylinder) 62a through hole 62b hole row 62c Through-hole formation range 63 Inner sleeve (inner cylinder) 64 Drive roller 65 supply nozzle 66 Pickup roller 67 Upper clamping roller 68 Lower clamping roller 70 Heat pressing device 71 Upper pressure roller (calender roller) 72 Lower pressure roller (calender roller) 80 Stretching device 91 Cut piece 92 Support member 93 First test piece 94 Second test piece 101 Test piece 102 Loop section 103 Overlap 104 Moving parts 105 load cells 106 Pressure element 107 Clamp MD machine direction CD Orthogonal direction D1 First dimension D2 Second dimension

Claims

1. A hook-and-loop fastener (10) made of synthetic resin, comprising a base portion (11) and a plurality of engaging elements (20) formed integrally with the base portion (11), each of the engaging elements (20) having a stem portion (21) protruding from the surface of the base portion (11) in the thickness direction of the base portion (11) and an engaging head portion (22) formed at the tip of the stem portion (21), wherein a cross section perpendicular to the thickness direction at least at the upper end of the stem portion (21) has a circular or nearly circular shape, and the engaging head portion (22) has a shape that expands entirely from the tip of the stem portion (21) in the direction perpendicular to the thickness direction, a lower half of the stem portion (21) including, in a first shape (31) of the engaging element (20) seen from the machine direction (MD), a portion where an outer surface (21a) facing a cross direction (CD) perpendicular to the machine direction (MD) is formed in a straight or substantially straight shape, and, in a second shape (32) of the engaging element (20) seen from the cross direction (CD), a portion where the outer surface (21a) facing the machine direction (MD) is curved toward the surface of the base portion (11); the curved portion of the outer surface (21 a) in the second shape (32) is provided over 30% or more of the range in the up-down direction of the lower half of the stem portion (21); The connecting portion of the stem portion (21) that connects to the base portion (11) has an elliptical or approximately elliptical shape that is long in the machine direction (MD). A hook-and-loop fastener characterized by:

2. In the second shape (32), the stem portion (21) includes a portion in an upper half of the stem portion (21) in which the outer surface (21a) facing the machine direction (MD) is formed in a straight or substantially straight shape, The straight or substantially straight portion of the second shape (32) is formed in a shorter range than the straight or substantially straight portion of the first shape (31). The hook-and-loop fastener according to claim 1.

3. A hook-and-loop fastener (10) made of synthetic resin, comprising a base portion (11) and a plurality of engaging elements (20) formed integrally with the base portion (11), each of the engaging elements (20) having a stem portion (21) protruding from the surface of the base portion (11) in the thickness direction of the base portion (11) and an engaging head portion (22) formed at the tip of the stem portion (21), wherein a cross section perpendicular to the thickness direction at least at the upper end of the stem portion (21) has a circular or nearly circular shape, and the engaging head portion (22) has a shape that expands entirely from the tip of the stem portion (21) in the direction perpendicular to the thickness direction, When the engaging element (20) is viewed in the machine direction (MD), a length in the orthogonal direction (CD) perpendicular to the machine direction (MD) of a connecting portion of the stem portion (21) that connects the stem portion (21) to the base portion (11) is defined as a first dimension (D1), and when the engaging element (20) is viewed in the orthogonal direction (CD), a length in the machine direction (MD) of the connecting portion of the stem portion (21) is defined as a second dimension (D2), the stem portion (21) has a shape in which the second dimension (D2) is larger than the first dimension (D1), a lower half of the stem portion (21) including a portion where an outer surface (21a) facing the machine direction (MD) curves toward the surface of the base portion (11) in a second shape (32) when the engaging element (20) is viewed from the cross direction (CD), the curved portion of the outer surface (21 a) in the second shape (32) is provided over 30% or more of the range in the up-down direction of the lower half of the stem portion (21); When the peel strength of the hook-and-loop fastener (10) when the hook-and-loop fastener (10) and the loop member that are engaged with each other are peeled along the machine direction (MD) and the cross direction (CD), respectively, the hook-and-loop fastener (10) has a shape in which the CD peel strength is greater than the MD peel strength because the second dimension (D2) is greater than the first dimension (D1). A hook-and-loop fastener characterized by:

4. A hook-and-loop fastener (10) made of synthetic resin, comprising a base portion (11) and a plurality of engaging elements (20) formed integrally with the base portion (11), each of the engaging elements (20) having a stem portion (21) protruding from the surface of the base portion (11) in the thickness direction of the base portion (11) and an engaging head portion (22) formed at the tip of the stem portion (21), wherein a cross section perpendicular to the thickness direction at least at the upper end of the stem portion (21) has a circular or nearly circular shape, and the engaging head portion (22) has a shape that expands entirely from the tip of the stem portion (21) in the direction perpendicular to the thickness direction, a lower half of the stem portion (21) including a portion where an outer surface (21a) facing the machine direction (MD) curves toward the surface of the base portion (11) in a second shape (32) when the engaging element (20) is viewed in a cross direction (CD) perpendicular to the machine direction (MD), the curved portion of the outer surface (21 a) in the second shape (32) is provided over 30% or more of the range in the up-down direction of the lower half of the stem portion (21); a connecting portion of the stem portion (21) connected to the base portion (11) has an elliptical or substantially elliptical shape that is elongated in the machine direction (MD), The CD flexibility when the portion of the hook-and-loop fastener (10) along the cross direction (CD) is bent in the thickness direction is superior to the MD flexibility when the portion of the hook-and-loop fastener (10) along the machine direction (MD) is bent in the thickness direction, because the connecting portion has an elliptical or approximately elliptical shape that is long in the machine direction (MD). A hook-and-loop fastener characterized by:

5. The plurality of engaging elements (20) are arranged in a row at regular intervals along the machine direction (MD) to form an element row (26); The plurality of element rows (26) are arranged at regular intervals in the orthogonal direction (CD), The engaging elements (20) of each element row (26) are arranged at positions shifted by half the pitch interval in the machine direction (MD) with respect to the positions of the engaging elements (20) of the element rows (26) adjacent in the cross direction (CD), The engaging elements (20) are arranged in a position in the machine direction (MD) such that a forming area (27) of the stem portion (21) of each engaging element (20) has an overlapping portion with a forming area (27) of the stem portion (21) of the engaging element (20) in the element row (26) adjacent to the engaging element (20) in the cross direction (CD). The hook-and-loop fastener according to any one of claims 1 to 4.

6. Each engaging element (20) has at least one claw portion (23) protruding from the outer periphery of the engaging head (22) in the cross direction (CD). The hook-and-loop fastener according to any one of claims 1 to 4.

7. In a first shape (32) of the engaging element (20) when viewed from the machine direction (MD), the outer surface (21a) of the stem portion (21) facing the cross direction (CD) is formed in a straight or substantially straight shape from the position of the upper end of the stem portion (21) where it is connected to the engaging head portion (22) to the position of the lower end of the stem portion (21) where it is connected to the base portion (11), In the second shape (32), the portion of the stem portion (21) where the outer surface (21a) facing the machine direction (MD) is formed in a straight or substantially straight shape is disposed in a range of 1 / 2 to 3 / 4 of the overall height dimension of the stem portion (21). The hook-and-loop fastener according to any one of claims 1 to 4.

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