Method of manufacturing hook and loop fasteners

Abstract

A hook-and-loop fastener production method according to the present invention is for producing a synthetic resin hook-and-loop fastener that has a base part (71) and a plurality of engagement elements (62), said method comprising: a molding step for using a melted synthetic resin to mold a pre-fastener body (60) provided with the plurality of engagement elements (62); and a thickness adjustment step for adjusting the thickness dimension of the hook-and-loop fastener after the molding step by pressing, in the thickness direction, the pre-fastener body (60) or a shape-altered fastener body (70) obtained by performing a shape-altering process at least once on at least part of the pre-fastener body (60). The thickness adjustment step includes causing at least two engagement elements (62) which are disposed in differing positions in an orthogonal direction (CD) to have differing reduction amounts in the thickness dimension of stem parts (64) thereof by applying differing pressing forces to the two engagement elements (62). Thus, it is possible to stably produce a hook-and-loop fastener in which the total thickness is suitably controlled at differing positions in the width direction.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a snap fastener.

Background Art

[0002] Conventionally, a snap fastener product has been known in which a female snap fastener having a plurality of loops (hereinafter referred to as a loop member) and a male snap fastener detachable from the loop member are used in combination. The male snap fastener has, for example, a flat base portion and a plurality of engaging elements protruding from the base portion and having a form such as a mushroom shape.

[0003] Snap fasteners are currently widely used in a variety of products, and are also used in products that are attached to and detached from the body, such as disposable diapers, diaper covers for infants, supporters for protecting joints of hands and feet, lumbar corsets (lower back pain belts), and gloves. Also, an example of a snap fastener used in disposable diapers and the like is disclosed in International Publication No. 2017 / 109902 (Patent Document 1).

[0004] The snap fastener described in Patent Document 1 has a base portion and a plurality of engaging elements protruding from the base portion. Each engaging element of 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 portion of the stem portion. The engaging head portion is provided with a plurality of minute claw portions protruding from the outer peripheral edge portion of the engaging head portion.

[0005] In the hook-and-loop fastener described in Patent Document 1, tiny claws are provided on the engaging head of each engaging element, making it easier for the loop of the loop member to catch on each engaging element, and making it difficult for the caught loop to detach from the engaging element. This increases the engagement strength (peel strength) of the hook-and-loop fastener to the loop member. Furthermore, in Patent Document 1, the claws that contribute to increasing the engagement strength are formed in a minute size on the outer edge of the engaging head, so the influence of the claws on the feel of the hook-and-loop fastener can be reduced. Therefore, it is possible to provide a hook-and-loop fastener that has high engagement strength while also having a good surface feel.

[0006] When manufacturing a hook-and-loop fastener like the one described in Patent Document 1, a primary molding process is first performed. In this primary molding process, molten thermoplastic resin is continuously extruded onto the outer surface of a rotating die wheel (mold) to form a primary molded body having a base portion and a plurality of primary elements provided on the base portion.

[0007] Next, the primary molded body having multiple primary elements is conveyed to a heating and pressing device that performs a secondary molding process. In this secondary molding process, the primary molded body is introduced between a pair of upper and lower rollers of the heating and pressing device, causing the upper ends of the primary elements to be pressed and deformed by the upper roller, thereby forming engaging elements with engaging heads from the primary elements. This secondary molding process manufactures the hook-and-loop fastener described in Patent Document 1. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] International Publication No. 2017 / 109902 [Overview of the project] [Problems that the invention aims to solve]

[0009] In recent years, there has been a growing demand to reduce the thickness between the top (first) and bottom (second) surfaces of hook-and-loop fasteners in order to lower manufacturing costs and improve their flexibility. However, in the primary molding process using the die wheel described above, there are limits to how thin the base portion formed on the outer surface of the die wheel can be, and there is a need to make it even thinner.

[0010] Furthermore, in order to reduce the thickness of the base portion, it is conceivable to, for example, send the hook-and-loop fastener obtained through a secondary molding process to a stretching device, and perform uniaxial stretching in the stretching device, in which the base portion is pulled along the machine direction (conveying direction) while the hook-and-loop fastener is heated. By performing such uniaxial stretching, the hook-and-loop fastener can be stretched in the machine direction, thereby reducing the thickness dimension of the base portion compared to before stretching.

[0011] However, when uniaxial stretching is performed, the thickness dimension from the bottom surface of the base to the top end of the engaging element (i.e., the total thickness dimension of the hook-and-loop fastener) decreases significantly in the central region in the width direction of the hook-and-loop fastener compared to the left and right side edge regions located on the outside in the width direction of the same fastener. As a result, in hook-and-loop fasteners that have undergone uniaxial stretching, a thickness change occurs in the width direction such that the total thickness dimension decreases from the left and right side edge regions towards the central region.

[0012] Thus, in hook-and-loop fasteners where thickness changes in the width direction occur, defects such as sagging or wavy wrinkles are more likely to occur in the base portion. Furthermore, when hook-and-loop fasteners with thickness changes in the width direction are wound onto a roll for recovery after manufacturing, for example, the left and right side edges of the fastener may be partially raised, or wrinkles (wound wrinkles) may have formed in the base portion of the fastener when it is wound onto the roll. If such partial raised areas or wound wrinkles remain on the hook-and-loop fastener, it could potentially degrade the quality or performance of the fastener.

[0013] Furthermore, if the hook-and-loop fastener has a slight thickness variation in the width direction that is not noticeable in its sheet state, this thickness variation may be amplified when the fastener is wound onto a roll after manufacturing. As a result, even slight thickness variations not caused by stretching could potentially degrade the quality or performance of the hook-and-loop fastener.

[0014] Incidentally, depending on the application of the hook-and-loop fastener, for example, there may be a need for a hook-and-loop fastener in which the total thickness dimension from the bottom surface of the base to the top end of the engaging element is intentionally or actively varied in the width direction, or a hook-and-loop fastener in which the thickness dimension of the engaging element is intentionally or actively varied at different positions in the width direction. However, when such a hook-and-loop fastener is manufactured using the method described in Patent Document 1, for example, it is necessary to newly create a mold for the molding equipment used in the primary molding process to correspond to the shape of the hook-and-loop fastener being manufactured. In this case, it leads to increased manufacturing costs and also presents the challenge of not being able to respond quickly to customer requests.

[0015] The present invention has been made in view of the above problems, and its object is to provide a method for manufacturing hook-and-loop fasteners that can stably manufacture hook-and-loop fasteners in which the thickness dimension from the second surface of the base portion to the top end of the engaging element provided on the first surface of the base portion is appropriately controlled at different positions in the width direction. [Means for solving the problem]

[0016] To achieve the above objective, the present invention provides a method for manufacturing a hook-and-loop fastener made of synthetic resin, comprising: a base portion having a first surface and a second surface arranged on opposite sides of each other; and a plurality of engaging elements, each engaging element comprising a stem portion protruding in the thickness direction from the first surface of the base portion; and an engaging head integrally formed at the tip of the stem portion, wherein the engaging head has a shape that expands in a direction perpendicular to the thickness direction from the tip of the stem portion, the method comprising: a molding step of forming a pre-fastener body having a plurality of engaging elements using molten synthetic resin; and after the molding step, pressing the pre-fastener body, or a deformed fastener body having undergone at least one deformation process on at least a part of the pre-fastener body, in the thickness direction, thereby reducing the thickness of the pre-fastener body or the deformed fastener body. The process includes a thickness adjustment step to adjust the thickness of the hook-and-loop fastener by reducing the thickness dimension in at least part of it, the forming step includes forming a row of engaging elements by arranging the engaging elements along the machine direction, and arranging a plurality of the rows of engaging elements in an orthogonal direction perpendicular to the machine direction, the thickness adjustment step includes, when the direction perpendicular to the machine direction in the thickness adjustment step is defined as the orthogonal direction, applying different pressing forces to at least two rows of engaging elements arranged at different positions in the orthogonal direction of the pre-fastener body or the deformed fastener body, thereby making the amount of reduction in the thickness dimension of the stem portion of the engaging elements forming one of the rows of engaging elements to which these different pressing forces are applied different from the amount of reduction in the thickness dimension of the stem portion of the engaging elements forming the other row of engaging elements, and To obtain a hook-and-loop fastener in which the engaging heads have the same shape as the engaging elements and the stems have different shapes as the engaging elements, between at least two of the engaging elements arranged at different positions in the orthogonal direction. This is a manufacturing method that includes [something].

[0017] The manufacturing method of the present invention preferably includes, in the thickness adjustment step, introducing the pre-fastener body or the deformed fastener body between a pair of upper and lower thickness adjustment rollers and pressing it in the thickness direction, and heating the pre-fastener body or the deformed fastener body at a temperature below the melting point of the synthetic resin using at least one of the upper and lower thickness adjustment rollers.

[0018] Furthermore, the manufacturing method of the present invention preferably includes, in the molding step, molding a temporary base portion which is integrally formed with a plurality of engagement elements and supports the engagement elements, and, after the molding step but before the thickness adjustment step, performing a stretching step in which the pre-fastener body is stretched along the machine direction, thereby reducing the thickness dimension of the temporary base portion and deforming the temporary base portion into the base portion, thereby forming the deformed fastener body.

[0019] Furthermore, the manufacturing method of the present invention preferably includes, in the thickness adjustment step, applying a greater pressing force to the engaging elements located outside the central region in the orthogonal direction than to the engaging elements located in the central region in the orthogonal direction.

[0020] In the manufacturing method of the present invention, it is preferable that the thickness adjustment step includes making the total thickness of the hook-and-loop fastener from the second surface of the base portion to the top end of the engaging element in the thickness direction uniform in the orthogonal direction by pressing in the thickness direction.

[0021] Furthermore, the manufacturing method of the present invention preferably includes, in the thickness adjustment step, forming at least two types of engagement elements, each having a different stem diameter in the central part of the stem portion in the thickness direction, at different positions in the orthogonal direction.

[0022] Furthermore, the manufacturing method of the present invention preferably includes, in the thickness adjustment step, forming at least a first engaging element disposed in the central region of the base portion in the orthogonal direction, and a second engaging element disposed outside the central region in the orthogonal direction, wherein the stem thickness of the central portion of the stem portion in the thickness direction is greater than that of the first engaging element. [Effects of the Invention]

[0024] According to the manufacturing method of the present invention, a surface fastener in which the dimensional thickness from the second surface of the base portion to the top end portion of the engaging element provided on the first surface of the base portion is appropriately controlled at different positions in the width direction can be stably manufactured.

Brief Description of Drawings

[0025] [Figure 1] It is a schematic diagram schematically explaining a manufacturing apparatus used in the manufacturing method according to an embodiment of the present invention. [Figure 2] It is a perspective view schematically showing an outer cylindrical body and an inner cylindrical body used in the primary forming apparatus of the manufacturing apparatus shown in FIG. 1. [Figure 3] It is a schematic diagram schematically explaining a deformation processing apparatus of the manufacturing apparatus shown in FIG. 1. [Figure 4] It is a cross-sectional view showing a main part of a cross-section taken along the line IV-IV of the thickness adjustment roller shown in FIG. 3. [Figure 5] It is a cross-sectional view showing a cross-section of a main part of a thickness adjustment roller according to a modification example. [Figure 6] It is a perspective view schematically showing a primary formed body formed in a primary forming step by a forming apparatus. [Figure 7] It is a perspective view schematically showing a pre-fastener body formed by a forming apparatus. [Figure 8] It is a front view of the engaging element of the pre-fastener body shown in FIG. 7 as viewed from the machine direction. [Figure 9] It is a front view of a deformed fastener body (stretched fastener body) obtained after stretching by a deformation processing apparatus as viewed from the machine direction. [Figure 10] It is a front view of the engaging element of the surface fastener manufactured by the manufacturing method according to the embodiment as viewed from the machine direction. [Figure 11] It is a front view of another engaging element of the surface fastener manufactured by the manufacturing method according to the embodiment as viewed from the machine direction.

Modes for Carrying Out the Invention

[0026] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings and examples. It should be noted that the present invention is not limited in any way to the embodiments described below, and various modifications are possible as long as they have substantially the same configuration as the present invention and produce similar effects. [Examples]

[0027] Figure 1 is a schematic diagram illustrating the manufacturing apparatus used in the manufacturing method according to this embodiment. Figure 2 is a schematic perspective view showing the outer cylindrical body and inner cylindrical body arranged in the primary molding apparatus of this manufacturing apparatus. Figure 3 is a schematic diagram illustrating the deformation processing apparatus of this manufacturing apparatus. In the following explanation, the machine direction (M direction or MD direction) refers to the direction along which the pre-fastener body, deformed fastener body, and hook-and-loop fastener are transported during the manufacturing process of the hook-and-loop fastener, and may also be referred to as the front-to-back direction. Furthermore, both the machine direction and the front-to-back direction are the longitudinal directions of the pre-fastener body, deformed fastener body, and hook-and-loop fastener that are formed into elongated lengths.

[0028] The orthogonal direction (direction C or CD) is perpendicular to the machine direction and is the width direction along the substantially flat or flat upper surface (first surface) of the base or temporary base, and is sometimes referred to as the left-right direction. The orthogonal direction and the left-right direction are the width directions of the elongated pre-fastener body, deformed fastener body, and hook-and-loop fastener.

[0029] The thickness direction is the direction perpendicular to the substantially flat or flat upper surface of the base portion, and is sometimes referred to as the vertical direction or height direction. Both the thickness direction and the vertical direction are perpendicular to both the mechanical direction and the orthogonal direction. In this case, the side from which the engaging element protrudes relative to the base portion is considered the upper side, and the opposite side is considered the lower side.

[0030] According to the method for manufacturing hook-and-loop fasteners of this embodiment, a hook-and-loop fastener made of synthetic resin is manufactured in which a plurality of engaging elements 62, including the engaging elements 62 shown in Figures 10 and 11, are integrally formed on a base portion 71. This hook-and-loop fastener is formed to be long along the machine direction MD of the manufacturing apparatus 1 shown in Figure 1.

[0031] The manufacturing apparatus 1 for producing such hook-and-loop fasteners will be explained with reference to Figures 1 to 3. The manufacturing apparatus 1 of this embodiment includes a primary molding apparatus 10 for primary molding, a heating and pressing apparatus (secondary molding apparatus) 20 for performing secondary molding on the primary molded body 50 formed by the primary molding apparatus 10 to form a pre-fastener body (secondary molded body) 60, and a deformation processing apparatus 30 for performing deformation processing on the obtained pre-fastener body 60.

[0032] In this invention, the pre-fastener body 60 refers to a molded body or component before deformation processing (particularly stretching 82) is performed when manufacturing a hook-and-loop fastener by deformation processing. The deformed fastener body 70 is a fastener body obtained by subjecting the pre-fastener body 60 to at least one deformation processing, such as stretching 82, and having the shape before being deformed into a finished hook-and-loop fastener. Specifically, in this embodiment, the deformed fastener body 70 is obtained by subjecting the pre-fastener body 60 to stretching 82, and is a fastener body in which the temporary base portion 51 of the pre-fastener body 60, described later, is deformed into a base portion 71 with a reduced thickness dimension, and before the thickness adjustment processing 83, described later, is performed.

[0033] The primary molding apparatus 10 includes a die wheel 11 that rotates in one direction (counterclockwise in the drawing), a supply nozzle 15 positioned opposite the circumferential surface of the die wheel 11 for continuously extruding (or flowing) molten synthetic resin material, and a pickup roller 16 positioned downstream of the supply nozzle 15 in the rotational direction of the die wheel 11.

[0034] The die wheel 11 comprises a cylindrical outer cylinder body (outer sleeve) 12 that serves as a mold, a cylindrical inner cylinder body (inner sleeve) 13 that is closely positioned inside the outer cylinder body 12, and a rotary drive roller 14 that rotates the outer cylinder body 12 and the inner cylinder body 13 in one direction. A cooling jacket (not shown) is provided inside the rotary drive roller 14 through which a cooling liquid is circulated.

[0035] The outer cylindrical body 12 has multiple through holes 12a that penetrate from the outer circumferential surface to the inner circumferential surface, forming cavities for forming the primary stem portion 52a of the primary molded body 50, which will be described later. The positions where the multiple through holes 12a are formed correspond to the positions where the engaging elements 62 are arranged in the manufactured pre-fastener body 60.

[0036] For example, in this embodiment, the multiple through holes 12a are arranged regularly in the mechanical direction MD (circumferential direction of the outer cylindrical body 12) and the orthogonal direction CD (direction parallel to the central axis of the outer cylindrical body 12). Each through hole 12a has a substantially frustoconical shape in which the circular area on the outer circumferential surface of the outer cylindrical body 12 is larger than the circular area on the inner circumferential surface of the outer cylindrical body 12. In this invention, the position, size, and shape of the multiple through holes 12a provided in the outer cylindrical body 12 are not particularly limited.

[0037] Multiple grooves 13a are formed on the outer circumferential surface of the inner cylindrical body 13. Each groove 13a is linearly formed along the direction CD, which is perpendicular to the central axis of the inner cylindrical body 13, and is recessed to a size that allows molten synthetic resin to flow into it. The multiple grooves 13a are formed at regular intervals along the circumferential direction (machining direction MD) of the inner cylindrical body 13. In addition, at least a portion of the grooves 13a of the inner cylindrical body 13 is positioned to intersect with the outer edge of the through hole 12a formed on the inner circumferential surface of the outer cylindrical body 12 when the die wheel 11 is assembled.

[0038] The pickup roller 16 has a pair of upper and lower clamping rollers 16a and 16b that grip and pull the primary molded body 50 formed on the outer circumferential surface of the die wheel 11 from above and below. The outer circumferential surfaces of the upper and lower clamping rollers 16a and 16b are provided with a surface layer (not shown) formed of an elastomer such as polyurethane elastomer.

[0039] The heating and pressing device 20 has a pair of upper and lower pressing rollers (calendar rollers) 21 and 22 positioned downstream of the pickup roller 16. The upper pressing roller 21 and the lower pressing roller 22 are positioned opposite each other with a predetermined gap between them. The gap between the upper pressing roller 21 and the lower pressing roller 22 can be adjusted by a height adjustment means (not shown).

[0040] The upper pressing roller 21 is equipped with a heating source (not shown) inside, and the surface temperature of the upper pressing roller 21 is set to a temperature that can soften the synthetic resin that forms the hook-and-loop fastener. In this invention, the structure of the heating and pressing device 20 is not particularly limited, as long as it is capable of pressing at least a part of the primary molded body 50 to form the engaging element 62, as will be described later.

[0041] As shown in Figure 3, the deformation processing device 30 is installed downstream of the heating and pressing device 20 to perform at least stretching 82 and thickness adjustment 83 on the pre-fastener body (secondary molded body) 60 formed by the heating and pressing device 20. The deformation processing device 30 includes a supply unit (not shown) for introducing the pre-fastener body 60 formed by the heating and pressing device 20 into the deformation processing device 30, a discharge unit (not shown) for sending the deformed hook-and-loop fastener to the downstream side, and a plurality of rotating rollers 31 arranged between the supply unit and the discharge unit along the transport path of the workpiece (i.e., the pre-fastener body 60 and the deformed fastener body 70).

[0042] Each rotating roller 31 is configured to transport the workpiece downstream at a speed corresponding to its rotational speed by rotating while in contact with the workpiece. Furthermore, at least a portion of the rotating roller 31 is configured so that a heating temperature is set by a control unit (not shown), and the workpiece is heated to the heating temperature by bringing it into contact with the outer surface of the roller.

[0043] The rotating roller 31 provided in the deformation processing device 30 includes a preheating roller 32, a first heating roller 33, and a second heating roller 34 for heating the prefastener body 60, a stretching roller 35 for stretching the prefastener body 60 between the second heating roller 34, a pair of upper and lower thickness adjustment rollers 41 and 42 for adjusting the thickness dimension of the manufactured hook-and-loop fastener, and a relaxation roller 36.

[0044] The preheating roller 32, the first heating roller 33, the second heating roller 34, the stretching roller 35, the upper and lower thickness adjustment rollers 41 and 42, and the relaxation roller 36 are installed in order along the transport path of the workpiece to be processed, from the supply section (upstream side) to the discharge section (downstream side) of the deformation processing device 30.

[0045] Furthermore, the thickness adjustment rollers 41 and 42 only need to be positioned downstream of the stretching roller 35, and do not need to be positioned immediately after the stretching roller 35. The relaxation roller 36 only needs to be positioned downstream of the thickness adjustment rollers 41 and 42, and does not need to be positioned immediately after the thickness adjustment rollers 41 and 42. In addition, in the deformation processing apparatus 30 of this embodiment, the stretching process 82 by the second heating roller 34 and the stretching roller 35 and the thickness adjustment process 83 by the thickness adjustment rollers 41 and 42 are performed continuously. However, in the present invention, the stretching process 82 and the thickness adjustment process 83 may be performed separately using different apparatuses.

[0046] In the deformation processing apparatus 30, the preheating roller 32, the first heating roller 33, the stretching roller 35, and the relaxation roller 36 are rotatably installed below the transport path of the workpiece to be processed so as to make direct contact with the temporary base portion 51 of the pre-fastener body 60 (described later) or the base portion 71 of the deformable fastener body 70 from the lower (back) side. The second heating roller 34 is rotatably installed above the transport path so as to make direct contact with the pre-fastener body 60 from the engagement element 62 side. This second heating roller 34 is provided with a support roller (nip roller) 34a that supports the temporary base portion 51 of the pre-fastener body 60 from the lower side. The upper and lower thickness adjustment rollers 41 and 42 are spaced apart from each other and are provided so as to be able to press the deformable fastener body 70 in the thickness direction.

[0047] Within the deformation processing device 30, the second heating roller 34 and the thickness adjustment rollers 41 and 42 are installed vertically below the installation positions of the preheating roller 32, the first heating roller 33, the stretching roller 35, and the relaxation roller 36, so as to cause the transport path of the workpiece to be processed to meander vertically.

[0048] The preheating roller 32, the first heating roller 33, and the second heating roller 34 of the deformation processing device 30 rotate at the same speed to transport the prefastener body 60 and heat the prefastener body 60 by bringing it into contact with the roller surfaces. By controlling the rotation speeds of the preheating roller 32, the first heating roller 33, and the second heating roller 34 to be the same, the prefastener body 60 can be transported to the second heating roller 34 while being heated without stretching the prefastener body 60. In addition, the second heating roller 34 and the support roller 34a positioned opposite the second heating roller 34 rotate at a constant speed while holding the prefastener body 60 from above and below.

[0049] In this embodiment, the preheating roller 32 and the first heating roller 33 contact the lower surface of the temporary base portion 51 of the prefastener body 60 to heat the prefastener body 60. The second heating roller 34 contacts the engaging element 62 of the prefastener body 60 to heat the prefastener body 60. As a result, before the prefastener body 60 is stretched by the stretching roller 35, the lower side of the prefastener body 60 (the side without the engaging element 62) is easily heated by the preheating roller 32 and the first heating roller 33, and the upper side of the prefastener body 60 (the side with the engaging element 62) is easily heated by the second heating roller 34.

[0050] In this embodiment, the deformation processing apparatus 30 is used to perform a heat treatment 81 on the pre-fastener body 60 before the stretching process 82 by a pre-heating roller 32, a first heating roller 33, and a second heating roller 34. However, in the present invention, the means and methods for performing the heat treatment 81 before the stretching process 82 are not particularly limited. For example, in this embodiment, one pre-heating roller 32 is installed upstream of the first heating roller 33, but a pre-heating roller is not required, or multiple pre-heating rollers may be installed upstream of the first heating roller 33. Furthermore, in this embodiment, the heat treatment 81 upstream of the second heating roller 34 is performed by directly contacting the pre-fastener body 60 with a heated rotating roller 31. However, in addition to or instead of this method, a method of heating the pre-fastener body 60 using heating means such as hot air or infrared irradiation may be used.

[0051] The stretching roller 35 rotates in contact with the lower surface of the temporary base portion 51 of the pre-fastener body 60. This transports the pre-fastener body 60 and heats it from the temporary base portion 51 side. The stretching roller 35 is controlled to rotate at a faster speed than the second heating roller 34. For example, in this embodiment, the rotational speed of the stretching roller 35 is set to 110% to 200% of the rotational speed of the second heating roller 34, preferably 140% to 170%.

[0052] This allows the pre-fastener body 60 to be stretched 82 between the second heating roller 34 and the stretching roller 35. This stretching 82 stretches the temporary base portion 51 of the pre-fastener body 60 in the machine direction MD to form the base portion 71. As a result, a deformable fastener body (stretched fastener body) 70 having the base portion 71 and a plurality of engaging elements 62 is obtained.

[0053] In this case, as described above, the second heating roller 34, together with the support roller 34a, conveys the pre-fastener body 60 while sandwiching it from above and below. This prevents the pre-fastener body 60, which is pulled by the high-speed stretching roller 35, from slipping against the second heating roller 34, and thus allows the pre-fastener body 60 to be stably fed toward the stretching roller 35 at a constant speed. As a result, the stretching process 82 can be stably performed on the pre-fastener body 60 between the slow-rotating second heating roller 34 and the high-rotating stretching roller 35.

[0054] The heating temperature of the stretching roller 35 is set lower than the melting point of the synthetic resin that forms the hook-and-loop fastener (pre-fastener body 60). Furthermore, it is preferable that the heating temperature of the stretching roller 35 be set higher than the heating temperature of the second heating roller 34.

[0055] The upper and lower thickness adjustment rollers 41 and 42 are positioned downstream of the stretching roller 35, and are arranged so that the deformation fastener body 70 passes between the upper and lower thickness adjustment rollers 41 and 42. The upper and lower thickness adjustment rollers 41 and 42 are controlled to rotate at the same rotational speed as each other and at the same rotational speed as the stretching roller 35. In this embodiment, as shown in Figure 4, the upper and lower thickness adjustment rollers 41 and 42 are straight-type rotating rollers, each having a shape in which the outer surface of the roller is parallel to the rotation axis.

[0056] The upper and lower thickness adjustment rollers 41 and 42 are provided with a height adjustment device (not shown) that allows adjustment of the distance 43 between the upper and lower thickness adjustment rollers 41 and 42. This height adjustment device maintains the upper and lower thickness adjustment rollers 41 and 42 in a state where there is a distance 43 between them that allows vertical pressure to be applied to the deformed fastener body 70 that has undergone stretching 82.

[0057] In this embodiment, the upper thickness adjustment roller 41 is formed as a heating roller equipped with a heating source. The heating temperature of the upper thickness adjustment roller 41 is set lower than the melting point of the synthetic resin forming the hook-and-loop fastener. The lower thickness adjustment roller 42 is not provided with a heating source. In this invention, it is sufficient that at least one of the upper and lower thickness adjustment rollers 41 and 42 is formed as a heating roller. That is, the lower thickness adjustment roller 42 may be formed as a heating roller, or both the upper and lower thickness adjustment rollers 41 and 42 may be formed as heating rollers.

[0058] By introducing and passing the deformable fastener body 70 through the gap 43 between the upper and lower thickness adjustment rollers 41 and 42 described above, the deformable fastener body 70 can be heated. Furthermore, a vertical pressing force can be applied to the portion of the deformable fastener body 70 whose total thickness is greater than the gap 43 between the upper and lower thickness adjustment rollers 41 and 42. This reduces the total thickness of at least a portion of the deformable fastener body 70 in the orthogonal direction CD (width direction) as it passes between the thickness adjustment rollers 41 and 42, thereby adjusting and controlling the total thickness of the manufactured hook-and-loop fastener in the orthogonal direction CD (width direction).

[0059] For example, in this embodiment, as shown in Figure 4, the outer surfaces of the upper thickness adjustment roller 41 and the lower thickness adjustment roller 42 are arranged parallel to each other so that the distance 43 between the upper and lower thickness adjustment rollers 41 and 42 is constant in the orthogonal direction CD. Therefore, the total thickness dimension of the hook-and-loop fastener passing between the upper and lower thickness adjustment rollers 41 and 42 can be made uniform in the orthogonal direction CD.

[0060] In this invention, the total thickness dimension of the deformable fastener body 70 and the hook-and-loop fastener refers to the dimension in the thickness direction from the lower surface of the base portion 71 of the deformable fastener body 70 or the hook-and-loop fastener to the upper end of the engaging element 62. In this embodiment, the size, shape, and structure of the upper and lower thickness adjustment rollers 41 and 42 are not particularly limited, and the upper and lower thickness adjustment rollers 41 and 42 only need to be formed so that they can press the deformable fastener body 70 or the pre-fastener body 60 in the thickness direction and reduce the thickness dimension of at least a part of the total thickness in the orthogonal direction CD (width direction).

[0061] The relaxation roller 36 is positioned downstream of the upper and lower thickness adjustment rollers 41 and 42, and is controlled to rotate at a slower rotational speed than the upper and lower thickness adjustment rollers 41 and 42. When the relaxation roller 36 is positioned immediately after the thickness adjustment rollers 41 and 42, it rotates while in contact with the hook-and-loop fastener that has undergone thickness adjustment processing 83, thereby transporting the hook-and-loop fastener and heating it from the base portion 71 side.

[0062] For example, in this embodiment, the rotational speed of the relaxation roller 36 is set to a speed of 80% to less than 100% of the rotational speed of the thickness adjustment rollers 41 and 42, preferably 90% to 99%. This reduces the tension applied to the hook-and-loop fastener between the thickness adjustment rollers 41 and 42 and the relaxation roller 36, thereby stabilizing the shape and dimensions of the hook-and-loop fastener (for example, the dimensions of the base portion 71 in the mechanical direction MD, the shape and thickness dimensions of each engaging element 62, etc.).

[0063] Next, a manufacturing method for producing hook-and-loop fasteners using a manufacturing apparatus 1 having the primary molding apparatus 10, heating and pressing apparatus 20, and deformation processing apparatus 30 described above will be explained.

[0064] The method for manufacturing the hook-and-loop fastener in this embodiment includes at least a molding step of forming a pre-fastener body 60 equipped with a plurality of engaging elements 62 as shown in Figures 7 and 8 using a primary molding device 10 and a heating and pressing device 20; a stretching step of forming a deformed fastener body 70 by performing a stretching process 82 (deformation process) along the machine direction MD on the pre-fastener body 60; and a thickness adjustment step of forming a hook-and-loop fastener by performing a thickness adjustment process 83 on the deformed fastener body 70.

[0065] Furthermore, the molding process includes at least a primary molding step in which a primary molded body 50 is molded in a primary molding apparatus 10, and a secondary molding step in which a pre-fastener body 60 is formed by heating the primary molded body 50 obtained in the primary molding step and pressing and deforming a part of the primary element 52 of the primary molded body 50, which will be described later.

[0066] In the primary molding process, molten synthetic resin is continuously supplied from the supply nozzle 15 toward the outer surface of the die wheel 11. In this embodiment, polypropylene is supplied from the supply nozzle 15 in a molten state as the synthetic resin for forming the hook-and-loop fastener. As a result, the temporary base portion 51 is continuously molded between the supply nozzle 15 and the die wheel 11. In addition, multiple primary elements (temporary elements) 52 are integrally molded into the temporary base portion 51 by the outer cylindrical body 12 and the inner cylindrical body 13 of the die wheel 11.

[0067] In this invention, the type of synthetic resin used to form the hook-and-loop fastener is not limited, and thermoplastic resins such as polypropylene, polyester, nylon, polybutylene terephthalate, or copolymers thereof can be used as the material for the hook-and-loop fastener. Furthermore, the primary molding apparatus may be configured such that molten synthetic resin material is supplied from a supply nozzle towards the gap between two opposing die wheels. In this case, the temporary base portion 51 is formed between a pair of die wheels, and the multiple primary elements are formed by the outer and inner cylindrical bodies of one of the die wheels.

[0068] In the primary molding process of this embodiment, a primary molded body 50 as shown in Figure 6 is formed. This primary molded body 50 has a thin plate-shaped temporary base portion 51 having an upper surface (first surface) and a lower surface (second surface), and a plurality of primary elements 52 protruding from the upper surface of the temporary base portion 51. The upper and lower surfaces of the temporary base portion 51 are formed to be flat or substantially flat. Each primary element 52 is deformed into an engaging element 62 by press molding in the secondary molding process.

[0069] In this embodiment, multiple primary elements 52 are regularly arranged on the upper surface of the temporary base portion 51 in a grid-like arrangement pattern aligned along the mechanical direction MD and the orthogonal direction CD. Therefore, multiple engaging elements 62 formed from the primary elements 52 are also regularly arranged in a grid-like arrangement pattern. In this case, the primary elements 52 (engaging elements 62) are arranged at a constant pitch (interval) along the mechanical direction MD to form a row of engaging elements 63. Furthermore, multiple rows of engaging elements 63 are arranged at a constant interval in the orthogonal direction CD. In particular, in this embodiment, seven rows of engaging elements 63 are provided.

[0070] In this invention, the number of primary elements 52 and the engaging elements 62 formed by deformation of the primary elements 52 are not particularly limited and can be changed. For example, the primary elements 52 of the primary molded body 50 and the engaging elements 62 of the hook-and-loop fastener may be arranged in a staggered pattern, where the engaging elements 62 are offset by a 1 / 2 pitch in the mechanical direction MD between adjacent engaging element rows 63 in the orthogonal direction CD, so as to be arranged alternately or in a zigzag pattern.

[0071] In this embodiment, each primary element 52 has a frustoconical primary stem portion 52a rising from a temporary base portion 51, a rod-shaped rib portion 52b that partially bulges upward from the upper surface of the primary stem portion 52a, and two protruding portions (primary claw portions) 52c that are integrally formed with the rib portion 52b and protrude from both ends of the rib portion 52b. In this case, each protruding portion 52c protrudes outward from the upper end surface of the primary stem portion 52a in a plan view of the primary element 52. The rib portion 52b and the protruding portions 52c are formed in the primary molding process by the synthetic resin flowing from the through hole 12a of the outer cylindrical body 12 into the groove portion 13a provided in the inner cylindrical body 13, and further entering along the groove portion 13a beyond the through hole 12a. For this reason, the rib portion 52b and the protruding portions 52c are formed along the orthogonal direction CD.

[0072] In this primary molding process, the molten synthetic resin is supported on the outer surface of the die wheel 11 and rotated half a turn while being cooled, thereby forming the primary molded body 50 described above. Subsequently, the primary molded body 50 is continuously peeled off the outer surface of the die wheel 11 by the pickup roller 16.

[0073] Next, the primary molded body 50, which has been peeled off the die wheel 11, is transported to the heating and pressing device 20 that performs the secondary molding process, and is introduced between the upper pressing roller 21 and the lower pressing roller 22 of the heating and pressing device 20.

[0074] In this secondary molding process, the temporary base portion 51 of the primary molded body 50 is supported from below by the lower pressing roller 22. At least the upper end of each primary element 52 of the primary molded body 50 is heated and softened by the upper pressing roller 21 and pressed from above. As a result, a pre-fastener body (secondary molded body) 60 is formed in which a plurality of engaging elements 62 are integrally molded on the upper surface of the temporary base portion 51, as shown in Figure 7. In this invention, the pre-fastener body 60 refers to the molded body before deformation processing such as stretching 82 is performed, or, if deformation processing such as stretching 82 is not performed, the molded body before thickness adjustment processing 83 is performed.

[0075] In this pre-fastener body 60, the multiple engaging elements 62 have the same shape, and the thickness dimension from the upper surface of the temporary base portion 51 of the engaging element 62 to the upper end of the engaging element 62 is also the same. In this case, having the same shape and thickness dimension of multiple engaging elements 62 includes not only cases where the multiple engaging elements 62 are formed with exactly the same shape and dimensions, but also cases where they are formed with substantially the same shape and dimensions so as not to cause any difference in the performance of the engaging elements 62.

[0076] Each engaging element 62 of the pre-fastener body 60 has a substantially frustoconical stem portion 64 rising from the temporary base portion 51, an engaging head portion 65 integrally formed at the upper end of the stem portion 64, and two minute claw portions (engaging claw portions) 66 protruding outward from the outer peripheral edge of the engaging head portion 65. The engaging head portion 65 has a shape that extends outward in a direction perpendicular to the thickness direction from the upper end (tip portion) of the stem portion 64. In a plan view (not shown) of the engaging element 62 viewed from above, the two claw portions 66 protrude from the engaging head portion 65 along the direction CD perpendicular to it. In this invention, the shape of the claw portions, the number of claw portions, and the direction of protrusion from the engaging head portion are not particularly limited.

[0077] Subsequently, the pre-fastener body 60, which has been fed out of the heating and pressing device 20, is transported to a deformation device 30 that performs stretching 82 and thickness adjustment 83. In the deformation device 30, the pre-fastener body 60 is introduced into the deformation device 30 from a supply unit (not shown), and the pre-fastener body 60 is subjected to heating 81, stretching 82, thickness adjustment 83, and relaxation 84 in order (see Figure 3).

[0078] Specifically, in the heat treatment 81, the pre-fastener body 60 is heated while being transported by the pre-heating roller 32, the first heating roller 33, and the second heating roller 34, which rotate at the same rotational speed. In this case, the pre-heating roller 32 and the first heating roller 33 bring the lower surface of the temporary base portion 51 of the pre-fastener body 60 into contact with the respective roller surfaces. This heats the pre-fastener body 60 to a temperature at which it can be stretched from the lower surface side of the temporary base portion 51.

[0079] Next, the pre-fastener body 60, which has passed through the pre-heating roller 32 and the first heating roller 33, is brought into contact with the second heating roller 34 from the side with the engaging element 62 (upper end side) to heat the pre-fastener body 60.

[0080] After the pre-fastener body 60 passes through the second heating roller 34, the pre-fastener body 60 is subjected to a uniaxial stretching process 82, in which it is stretched along the machine direction MD between the second heating roller 34 and a stretching roller 35 that rotates at a faster rotational speed than the second heating roller 34 (stretching process).

[0081] In this uniaxial stretching process 82, the heating temperature of the stretching roller 35 is set lower than the melting point of the synthetic resin, as described above. In addition, the rotational speed of the stretching roller 35 is set to a speed of 110% to 200% of the rotational speed of the second heating roller 34, preferably 140% to 170%. This allows for a stable tension to be applied to the pre-fastener body 60 along the machine direction MD between the second heating roller 34 and the stretching roller 35, thereby enabling the pre-fastener body 60 to undergo stretching 82 in the machine direction MD.

[0082] This uniaxial stretching process 82 allows the temporary base portion 51 to be easily stretched in the machine direction MD to form a base portion 71 having an upper surface (first surface) and a lower surface (second surface). Furthermore, the thickness between the upper and lower surfaces of the base portion 71 can be made thinner than the thickness of the temporary base portion 51 after the secondary molding process (in other words, the thickness dimension between the upper and lower surfaces of the base portion 71 can be made smaller than the thickness dimension of the temporary base portion 51). At the same time, it causes a reduction in the width dimension (dimension in the orthogonal direction CD) of the base portion 71 stretched in the machine direction MD.

[0083] Furthermore, because the base portion 71 is in contact with the stretching roller 35, the thermal deformation of the engagement element 62 is suppressed more than that of the base portion 71, and the shape of the engagement head 65 and claw portion 66 of each engagement element 62 can be maintained. On the other hand, since each engagement element 62 is integrated with the temporary base portion 51, when the temporary base portion 51 is stretched in the machine direction MD by the uniaxial stretching process 82 and deformed into the base portion 71, a part of the synthetic resin forming the engagement element 62 (especially the stem portion 64) moves towards the temporary base portion 51 (base portion 71), reducing the thickness dimension of the engagement element 62 from the base portion 71 compared to before the stretching process.

[0084] In particular, in this case, by performing uniaxial stretching 82 on the pre-fastener body 60, the base portion 71 stretches in the machine direction MD and shrinks in the width direction. As a result, the thickness dimension (height dimension) of the engaging element 62 located in the central region of the orthogonal direction CD (width direction) of the pre-fastener body 60 is significantly reduced compared to the engaging elements 62 located at the left and right outer edges of the orthogonal direction CD. Consequently, the total thickness dimension of the deformed fastener body 70 in the orthogonal direction CD differs by approximately 15 μm or more between the left and right outer edges of the orthogonal direction CD and the central region.

[0085] For example, in the pre-fastener body 60 of this embodiment, as described above, multiple engagement element rows 63 along the mechanical direction MD are provided at different positions in the orthogonal direction CD. In Figure 9, the multiple engagement element rows 63 are shown divided into seven regions in the orthogonal direction CD, and only one engagement element row 63 in each region is shown. In this case, for example, as shown in Figure 9, which shows a cross-section of the pre-fastener body 60 orthogonal to the mechanical direction MD for the region where the engagement element 62 is provided, the engagement element row 63 located on the far left in the orthogonal direction CD is defined as the first engagement element row 63a, and the engagement element rows 63 in the region adjacent to the first engagement element row 63a to the engagement element row 63 located on the far right are defined in order as the second engagement element row 63b to the seventh engagement element row 63g.

[0086] In the pre-fastener body 60 subjected to uniaxial stretching 82 in this embodiment, as shown in Figure 9, the thickness dimension of the engaging elements 62 of the fourth engaging element row 63d, which is located in the central region of the orthogonal direction CD, is smallest. Also, the thickness dimension of the engaging elements 62 of each engaging element row 63 located outside the orthogonal direction CD from the fourth engaging element row 63d is larger than that of the engaging elements 62 of the engaging element row 63 located inside the orthogonal direction CD from that engaging element row 63. The thickness dimensions of the engaging elements 62 of the first engaging element row 63a, located on the far left of the orthogonal direction CD, and the seventh engaging element row 63g, located on the far right, are the largest. In this invention, the engaging element row 63 located in the central region of the orthogonal direction CD is sometimes referred to as the central engaging element row 67, and the engaging element row 63 located on the far outside of the orthogonal direction CD is sometimes referred to as the end engaging element row 68.

[0087] Therefore, by performing uniaxial stretching 82 on the pre-fastener body 60, a deformed fastener body 70 is obtained in which a base portion 71 stretched in the machine direction MD has rows of engaging elements 62 of different heights 63 formed at different positions in the width direction. Subsequently, the obtained deformed fastener body 70 passes through the stretching roller 35 and is conveyed towards the upper and lower thickness adjustment rollers 41 and 42.

[0088] Next, the upper and lower thickness adjustment rollers 41 and 42 perform a thickness adjustment process 83 on the deformed fastener body 70 that has undergone the stretching process 82 (thickness adjustment process). In this thickness adjustment process, the distance 43 between the upper and lower thickness adjustment rollers 41 and 42 is set to a size corresponding to the total thickness dimension of the hook-and-loop fastener to be manufactured. Each of the upper and lower thickness adjustment rollers 41 and 42 is controlled to rotate at the same rotational speed as the stretching roller 35. Furthermore, the heating temperature of the upper thickness adjustment roller 41 is set lower than the melting point of the synthetic resin that forms the hook-and-loop fastener, as described above. The temperature of the lower thickness adjustment roller 42 is not particularly controlled and is left in a room temperature atmosphere.

[0089] Therefore, the thickness adjustment process 83 can be performed by passing the deformable fastener body 70, in which the engaging elements 62 have different thickness dimensions at different positions in the width direction, between the upper and lower thickness adjustment rollers 41 and 42. This thickness adjustment process 83 allows the deformable fastener body 70 to be heated and pressed in the thickness direction, thereby deforming at least a portion (in particular, at least a portion of the engaging elements 62) of the deformable fastener body 70 in the orthogonal direction CD.

[0090] In this process, in areas where the engaging elements 62 are positioned higher (for example, where the end engaging element row 68 is provided), a relatively large pressing force is applied to the deformable fastener body 70, thereby significantly reducing the thickness of the deformable fastener body 70. Conversely, in areas where the engaging elements 62 are positioned lower (for example, where the central engaging element row 67 is provided), a relatively small pressing force is applied to the deformable fastener body 70, thereby reducing the thickness of the deformable fastener body 70 (or preventing any reduction in thickness). Thus, the thickness adjustment process 83 allows for the adjustment of the thickness of the manufactured hook-and-loop fastener by varying the amount of reduction in the thickness of the engaging elements 62 due to pressing, for engaging elements 62 provided at different positions in the orthogonal direction CD and having different thicknesses.

[0091] For example, in this embodiment, the deformable fastener body 70 subjected to the thickness adjustment process 83 has, as described above, seven engagement element rows 63a to 7th engagement element rows 63g in seven regions along the machine direction MD, provided at different positions in the orthogonal direction CD. Furthermore, the thickness dimension of the engagement element 62 in each engagement element row 63 is greater than that of the engagement element 62 in the engagement element row 63 adjacent to that engagement element row 63, which is located further inside the orthogonal direction CD. Moreover, the central engagement element row 67 (4th engagement element row 63d) provided in the central region of the orthogonal direction CD has the smallest thickness dimension of the engagement element 62.

[0092] Therefore, by performing a thickness adjustment process 83 on such a deformed fastener body 70, a large pressing force is applied to the engaging elements 62 of the end engaging element rows 68 (first engaging element row 63a and seventh engaging element row 63g) located on the outermost side of the orthogonal direction CD, thereby significantly reducing the thickness of the engaging elements 62. Furthermore, as the position of the engaging element row 63 moves closer to the inside of the orthogonal direction CD, a smaller pressing force is applied to the engaging elements 62, thus gradually reducing the amount of thickness reduction.

[0093] Furthermore, the engagement element 62 of the central engagement element row 67 (fourth engagement element row 63d) is pressed with the smallest pressing force among the seven regions of the engagement element row 63, so that the thickness dimension of the engagement element 62 can be reduced to the smallest possible size, or the thickness dimension of the engagement element 62 can be maintained without changing it by the thickness adjustment process 83.

[0094] Therefore, in this embodiment, by performing such thickness adjustment processing 83, a hook-and-loop fastener can be formed from the deformed fastener body 70, and the thickness dimension of the hook-and-loop fastener can be adjusted in the orthogonal direction CD, making the total thickness dimension of the hook-and-loop fastener uniform along the orthogonal direction CD. Specifically, the difference in the total thickness dimension of the hook-and-loop fastener in the orthogonal direction CD between the position of the orthogonal direction CD with the largest thickness dimension and the position of the orthogonal direction CD with the smallest thickness dimension can be kept to within approximately 10 μm.

[0095] Furthermore, the engaging elements 62 of the central engaging element row 67 after the thickness adjustment process 83 can have the same or substantially the same shape as the shape before the thickness adjustment process 83 (see Figure 9), as shown in Figure 10. For this reason, the stem portion 64 of the engaging elements 62 of the central engaging element row 67 has a substantially frustoconical shape in which the area of ​​the cross-section perpendicular to the thickness direction gradually decreases as it moves away from the base portion 71.

[0096] In the thickness adjustment process of this embodiment, the engagement elements 62 of the end engagement element rows 68 (first engagement element row 63a and seventh engagement element row 63g) located on the outermost side in the orthogonal direction CD are subjected to a thickness adjustment process 83, which significantly reduces their thickness and deforms them into the shape shown in Figure 11. Specifically, the shape of the engagement elements 62 of the end engagement element rows 68 is described as follows: when viewing the engagement element 62 from one side (front side) in the machine direction MD, for example, the stem portion 64 of the engagement element 62 is formed with a thicker stem diameter 75 in the central part of the stem portion 64 in the thickness direction compared to the engagement element 62 before the thickness adjustment process 83 (see Figure 9).

[0097] Here, the stem thickness 75 refers to the maximum dimension of the stem portion 64 in the direction perpendicular to the thickness direction when the engaging element 62 is viewed from a direction perpendicular to the thickness direction (for example, the mechanical direction MD or the perpendicular direction CD), or the diameter of the stem portion 64 when the engaging element 62 is viewed in a cross-section perpendicular to the thickness direction. Furthermore, the central portion of the stem portion 64 in the thickness direction refers to the portion that falls within the range of 25% to 75% from the base end of the stem portion 64, when the thickness dimension from the base end of the stem portion 64 connected to the base portion 71 to the boundary between the stem portion 64 and the engaging head portion 65 is taken as 100%, and is aligned in the direction perpendicular to the thickness direction.

[0098] In particular, in the end engagement element row 68, the stem portion 64 of the engagement element 62 has a barrel shape, as shown in Figure 11, in which the stem thickness 75 at the center of the stem portion 64 in the thickness direction is thicker than the respective stem thicknesses 75 at the upper and lower ends of the stem portion 64 in the thickness direction.

[0099] In this case, the stem diameter 75 at the center of the stem portion 64 in the thickness direction is greater than the diameter at the base end, which is the connection point between the stem portion 64 and the base portion 71 (the dimension perpendicular to the thickness direction). Furthermore, the stem diameter 75 at the center of the stem portion 64 in the thickness direction is greater than the diameter at the boundary between the stem portion 64 and the engaging head portion 65 (the dimension perpendicular to the thickness direction), and is smaller than the maximum diameter of the engaging head portion 65 (i.e., the diameter at the upper end of the engaging head portion 65).

[0100] The barrel-shaped stem portion 64 improves the strength of the engaging element 62. Specifically, the multiple engaging elements 62 in this embodiment include at least a first engaging element 62 arranged in the central engaging element row 67 (fourth engaging element row 63d) and a second engaging element 62 arranged in the end engaging element row 68 (first engaging element row 63a and seventh engaging element row 63g), the second engaging element 62 having a stem diameter 75 greater than that of the first engaging element 62.

[0101] Furthermore, in the end engagement element row 68, the engagement head 65 and claw portion 66 of the engagement element 62 do not change shape, or hardly change shape, before and after the thickness adjustment process 83. For this reason, the engagement head 65 and claw portion 66 of the engagement element 62 that has undergone the thickness adjustment process 83 have the same shape as the engagement head 65 and claw portion 66 of the engagement element 62 immediately after the stretching process 82, and also have the same shape as the engagement head 65 and claw portion 66 of the engagement element 62 (i.e., the engagement element 62 of the pre-fastener body 60) before being introduced into the deformation processing device 30.

[0102] Furthermore, in this embodiment, in the engagement element rows 63 (second, third, fifth, and sixth engagement element rows 63b, 63c, 63e, 63f) located inside the direction CD orthogonal to the end engagement element row 68, the stem thickness 75 in the central part of the stem portion 64 in the thickness direction decreases as the position of the engagement element row 63 approaches the central engagement element row 67 (fourth engagement element row 63d). Also, the shape of the stem portion 64 is in the transitional stage from the barrel shape shown in Figure 11 to the approximately frustoconical shape shown in Figure 10. As the position of the engagement element row 63 approaches the central engagement element row 67, it has a shape closer to the approximately frustoconical shape shown in Figure 10, and as it approaches the end engagement element row 68, it has a shape closer to the barrel shape shown in Figure 11.

[0103] In other words, the seven engagement element rows 63 shown in Figure 9 of this embodiment are divided into four types of engagement elements 62 after the thickness adjustment process: the engagement elements 62 of the first engagement element row 63a and the seventh engagement element row 63g, the engagement elements 62 of the second engagement element row 63b and the sixth engagement element row 63f, the engagement elements 62 of the third engagement element row 63c and the fifth engagement element row 63e, and the engagement elements 62 of the fourth engagement element row 63d. These four types of engagement elements 62 are formed with different stem portion shapes (especially the shape of the central part of the stem portion 64 in the thickness direction) and the same thickness dimension from the base portion 71 to the upper end of the engagement head 65.

[0104] It should be noted that the engaging element 62 is not limited to these four shapes. As described above, as you move from the end engaging element row 68 towards the central engaging element row 67, the stem diameter 75 in the center of the stem portion 64 in the thickness direction becomes smaller, and the shape of the stem portion 64 smoothly changes from the barrel shape shown in Figure 11 to the roughly frustoconical shape shown in Figure 10.

[0105] For example, when multiple engagement element rows 63 are divided into nine regions in the orthogonal direction CD, the variation in stem thickness 75 across the five regions from the leftmost region to the central region of the orthogonal direction CD can be quantified as follows. For each of the five regions, the stem thickness 75 at the center of the stem portion 64 in the thickness direction of each engagement element 62 was measured (n=16), and the coefficient of variation, which indicates the numerical variation of the stem thickness 75 in the five regions, was calculated. As a result, if the thickness adjustment process is not passed, the coefficient of variation of the stem thickness 75 at the center in the thickness direction for the engagement elements 62 in the five regions of the orthogonal direction CD is a small value of less than 0.020. On the other hand, in the case of the hook-and-loop fastener manufactured in this embodiment, the coefficient of variation of the stem thickness 75 at the center in the thickness direction for the engagement elements 62 in the five regions of the orthogonal direction CD was a large value of 0.020 or more (specifically, 0.023). Therefore, it was confirmed that in the hook-and-loop fasteners manufactured in this embodiment, the stem thickness 75 of the engaging element 62 varies considerably in the five regions described above in the orthogonal direction CD. This variation in the stem thickness 75 of the engaging element 62 is caused by the thickness adjustment process 83 performed in this embodiment.

[0106] Furthermore, in the thickness adjustment process 83 of this embodiment, although the stem portion 64 of the engaging element 62 is deformed to change the thickness dimension of the engaging element 62, the engaging head portion 65 and claw portion 66 of the engaging element 62 are not deformed. Therefore, in the hook-and-loop fastener obtained by performing the thickness adjustment process 83, multiple engaging elements 62 that are positioned differently in the orthogonal direction CD and have different shapes of stem portions 64 have engaging head portions 65 and claw portions 66 that are formed to be the same shape. In this case, having the same shape for the engaging head portion 65 and claw portion 66 includes not only cases where the engaging head portion 65 and claw portion 66 are formed to be exactly the same shape and dimensions, but also cases where the engaging head portion 65 and claw portion 66 are formed to be approximately the same shape and dimensions so as not to cause any difference in the performance of the engaging element 62.

[0107] After performing the thickness adjustment process 83 described above, a relaxation process 84 is performed on the hook-and-loop fastener having the engaging element 62 shown in Figures 10 and 11. In this relaxation process 84, the hook-and-loop fastener is transported between the thickness adjustment rollers 41 and 42 and a relaxation roller 36 that rotates at a slower rotational speed than the thickness adjustment rollers 41 and 42, with the tension applied to the hook-and-loop fastener being reduced. This stabilizes the shape of the hook-and-loop fastener, in which the total thickness dimension is uniform along the orthogonal direction CD, between the thickness adjustment rollers 41 and 42 and the relaxation roller 36.

[0108] After passing through the relaxation roller 36, the hook-and-loop fastener is sent out from a discharge section (not shown) of the deformation processing device 30. The hook-and-loop fastener discharged from the deformation processing device 30 is then wound into a roll and collected, for example, on a recovery roller. Alternatively, the hook-and-loop fastener may be transported from the deformation processing device 30 to a cutting section (not shown), where it may be cut to a predetermined width and / or length before being collected. A hook-and-loop fastener is manufactured by performing the manufacturing method of this embodiment, which includes each process and treatment from the molding process to the relaxation treatment 84 described above.

[0109] In the hook-and-loop fastener manufactured by the manufacturing method of this embodiment, multiple engaging elements 62 are provided on the upper surface of the base portion 71. Furthermore, since the hook-and-loop fastener of this embodiment is subjected to uniaxial stretching 82 along the machine direction MD, the thickness of the base portion 71 can be made thinner compared to, for example, a conventional hook-and-loop fastener that is not subjected to stretching 82. Therefore, the hook-and-loop fastener of this embodiment can obtain the effects of a thinner base portion 71, such as improved flexibility, reduced weight, improved productivity, and reduced manufacturing costs.

[0110] Furthermore, although the hook-and-loop fastener of this embodiment undergoes uniaxial stretching 82, a thickness adjustment process 83 is continuously performed in the machine direction MD after the uniaxial stretching 82, thereby controlling the total thickness dimension of the hook-and-loop fastener in the orthogonal direction CD. This prevents or suppresses changes in the total thickness dimension of the hook-and-loop fastener in the orthogonal direction CD (width direction), resulting in a hook-and-loop fastener with a uniform total thickness dimension throughout the entire orthogonal direction CD and throughout the entire machine direction MD. In other words, according to the manufacturing method of this embodiment, hook-and-loop fasteners can be stably manufactured in which the total thickness dimension is the same in both the central region in the width direction and in the left and right side edge regions.

[0111] Therefore, defects such as sagging or wavy wrinkles caused by changes in thickness in the width direction can be prevented in the base portion 71 of the manufactured hook-and-loop fastener. Furthermore, when the hook-and-loop fastener is wound onto a recovery roller for recovery after manufacturing, as described above, it can be prevented from partially bulging the left and right side edges of the hook-and-loop fastener or from developing wrinkles (wound wrinkles) in the base portion 71. Consequently, it is possible to prevent a decrease in the quality or performance of the hook-and-loop fastener due to these defects or problems during recovery, and to stably provide hook-and-loop fasteners with good quality and performance.

[0112] In the above-described embodiment, the method for manufacturing hook-and-loop fasteners involves performing a thickness adjustment process 83 on a deformed fastener body 70, which has undergone stretching 82 and whose total thickness dimension changes at different positions in the orthogonal direction CD (width direction). This process results in the production of a hook-and-loop fastener with a uniform total thickness dimension in the orthogonal direction CD.

[0113] However, in the present invention, for example, by performing a thickness adjustment process 83 on the pre-fastener body 60 (see Figures 7 and 8) obtained by the molding process of the above-described embodiment, it is possible not only to make the total thickness uniform in the orthogonal direction CD, but also to manufacture hook-and-loop fasteners in which the thickness dimension of the engaging element 62 is intentionally or actively changed at different positions in the width direction.

[0114] For example, in a pre-fastener body 60 that has not undergone stretching 82, variations in processing conditions such as molding temperature and cooling temperature in the orthogonal direction CD, and the influence of the processing dimensional accuracy of the molding die, may result in a difference of approximately 10 μm in thickness between the position in the orthogonal direction CD where the total thickness is greatest and the position in the orthogonal direction CD where the thickness is smallest. In this case, by introducing and passing the pre-fastener body 60 between the upper and lower thickness adjustment rollers 46 and 47, the pressing force applied to the engaging elements 62 at different positions in the orthogonal direction CD of the pre-fastener body 60 can be changed. This makes it possible to limit the difference in thickness between the position in the orthogonal direction CD where the total thickness is greatest and the position in the orthogonal direction CD where the thickness is smallest to within approximately 5 μm.

[0115] Furthermore, for the pre-fastener body 60 shown in Figures 7 and 8, in which the total thickness dimension from the lower surface of the temporary base portion 51 to the upper end of the engaging element 62 is a constant size in the width direction, it is also possible to perform a thickness adjustment process 83 using a pair of upper and lower thickness adjustment rollers 46, 47 according to a modified example shown in Figure 5, without performing the heat treatment 81 (see Figure 3) described above, and without performing the stretching process 82.

[0116] In this modified example, the upper and lower thickness adjustment rollers 46 and 47 are spaced apart from each other so that the pre-fastener body 60 can pass between the two thickness adjustment rollers 46 and 47. Furthermore, the upper and lower thickness adjustment rollers 46 and 47 are provided with a height adjustment device (not shown) that allows for adjustment of the distance between the thickness adjustment rollers 46 and 47.

[0117] In this modified example, the upper thickness adjustment roller 46 is a crown-type rotating roller with a shape in which the outer surface of the roller bulges outwards in a convex shape in the central part of the orthogonal direction CD, and is also formed as a heating roller equipped with a heating source. The lower thickness adjustment roller 47 is a straight-type rotating roller with a shape in which the outer surface of the roller is parallel to the rotation axis direction.

[0118] By introducing and passing a pre-fastener body 60, whose total thickness is constant in the width direction, between the upper and lower thickness adjustment rollers 46 and 47, the pre-fastener body 60 can be pressed in the thickness direction. In particular, in this case, the distance between the upper and lower thickness adjustment rollers 46 and 47 becomes smaller in the central part of the orthogonal direction CD of the upper thickness adjustment roller 46, and larger in the part closer to the outer edge of the orthogonal direction CD.

[0119] Therefore, in the central part of the orthogonal direction CD by the upper and lower thickness adjustment rollers 46 and 47, a relatively large pressing force is applied to the pre-fastener body 60, significantly reducing the thickness dimension of the pre-fastener body 60, while in the outer part of the orthogonal direction CD, the thickness dimension of the pre-fastener body 60 can be reduced to a smaller degree (or not reduced at all). As a result, it is possible to manufacture hook-and-loop fasteners in which the total thickness dimension is reduced in the central part of the orthogonal direction CD and gradually increases as it approaches the outer part of the orthogonal direction CD, with the thickness intentionally or actively varied in the orthogonal direction CD.

[0120] The upper thickness adjustment roller 46 may be a crown-type rotating roller with a concave shape in the central part of the orthogonal direction CD, and is not particularly limited as long as it can apply different pressing forces to the engaging element 62 at different positions in the orthogonal direction CD.

[0121] Furthermore, the upper thickness adjustment roller 46 may be a rotating roller with a shape in which the diameter is varied so that the outer surface of the roller forms a step in the orthogonal direction CD. By introducing and passing a pre-fastener body 60, for example, whose total thickness is constant in the width direction, between the upper and lower thickness adjustment rollers 46 and 47, different pressing forces can be applied to different regions of the pre-fastener body 60 in the orthogonal direction CD. After that, the hook-and-loop fastener that has undergone thickness adjustment is cut to a predetermined width dimension for each region that has received different pressing forces. In this way, multiple hook-and-loop fasteners with different total thickness dimensions can be manufactured in a single manufacturing process.

[0122] Furthermore, in the present invention, a deformed fastener body may be formed by performing a deformation process other than stretching 82 on the pre-fastener body 60, either in place of or in addition to stretching 82, and then performing a thickness adjustment process 83 on the resulting deformed fastener body. For example, the pre-fastener body 60 shown in Figures 7 and 8 may be embossed, slit, or punched. By performing a thickness adjustment process 83 on a deformed fastener body that has undergone at least one of these deformation processes, it is possible to manufacture a hook-and-loop fastener in which the total thickness dimension is uniform in the orthogonal direction CD, or to manufacture a hook-and-loop fastener in which the dimension in the thickness direction is intentionally or actively changed.

[0123] In the above-described embodiment, the pre-fastener body 60 is manufactured by performing a primary molding process using a primary molding device 10 and a secondary molding process using a heating and pressing device 20. However, in the present invention, the method and means of molding the pre-fastener body are not particularly limited. In the present invention, for example, the pre-fastener body 60 to be sent to the deformation process may be manufactured by performing a molding process in a molding device provided with a cavity capable of molding an engaging element 62 having a stem portion 64 and an engaging head portion 65, without performing a secondary molding process that causes thermal deformation as in the above-described embodiment. [Explanation of Symbols]

[0124] 1 Manufacturing equipment 10 Primary forming equipment 11 Die Wheels 12. Outer cylindrical body (outer sleeve) 12a Through hole 13. Inner cylindrical body (inner sleeve) 13a Groove 14 Rotating Drive Rollers 15 supply nozzles 16 Pickup Roller 16a Upper clamping roller 16b Lower clamping roller 20. Heating and pressing device (secondary molding device) 21 Upper pressure roller 22 Lower pressure roller 30 Deformation Processing Equipment 31 Rotating Rollers 32 Preheating rollers 33. First heating roller 34. Second heating roller 34a Support roller (nip roller) 35 Stretching Roller 36 Relaxation Roller 41 Upper thickness adjustment roller 42 Lower thickness adjustment roller 43 interval 46 Upper thickness adjustment roller 47 Lower thickness adjustment roller 50 Primary molded object 51 Temporary base section 52 Primary element (provisional element) 52a Primary stem section 52b Rib section 52c Projection part (primary claw part) 60 Pre-fastened body (secondary molded body) 62 Engagement element 63 Engagement element array 63a~63g First engagement element row~Seventh engagement element row 64 Stem section 65 Engagement head 66 Claw portion (engaging claw portion) 67 Central engagement element row 68 End-engagement element row 70 Deformable Zipper Body 71 Base section 75. Stem diameter at the center of the stem in the thickness direction. 81 Heat treatment 82 Stretching 83 Thickness adjustment processing 84. Mitigation CD orthogonal direction MD machine direction

Claims

1. A manufacturing method for a hook-and-loop fastener made of synthetic resin, comprising a base portion (71) having a first surface and a second surface arranged on opposite sides of each other, and a plurality of engaging elements (62), each engaging element (62) comprising a stem portion (64) protruding in the thickness direction from the first surface of the base portion (71), and an engaging head (65) integrally formed at the tip of the stem portion (64), wherein the engaging head (65) has a shape that widens in a direction perpendicular to the thickness direction from the tip of the stem portion (64), A molding step of forming a pre-fastener body (60) equipped with a plurality of engagement elements (62) using the molten synthetic resin, A thickness adjustment step is performed after the molding step, in which the thickness dimension of the hook-and-loop fastener is adjusted by pressing the pre-fastener body (60), or the deformed fastener body (70), which has been deformed at least once on at least a part of the pre-fastener body (60), in the thickness direction, thereby reducing the thickness dimension of at least a part of the pre-fastener body (60) or the deformed fastener body (70). Includes, The molding process described above is: By arranging the aforementioned engaging elements (62) along the mechanical direction (MD), a row of engaging elements (63) is formed, and The multiple engagement element rows (63) are arranged in an orthogonal direction (CD) perpendicular to the mechanical direction (MD). Includes, The aforementioned thickness adjustment step is When the direction perpendicular to the machine direction (MD) of the thickness adjustment process is defined as the orthogonal direction (CD), by applying different pressing forces to at least two rows of engagement elements (63) arranged at different positions in the orthogonal direction (CD) of the pre-fastener body (60) or the deformable fastener body (70), the amount of reduction in the thickness dimension of the stem portion (64) of the engagement element forming one of the rows of engagement elements (63) and the amount of reduction in the thickness dimension of the stem portion (64) of the engagement element forming the other row of engagement elements (63) are made different between the two rows of engagement elements (63) to which these different pressing forces have been applied, and To obtain a hook-and-loop fastener in which, between at least two of the engaging elements (62) arranged at different positions in the orthogonal direction (CD), the engaging heads (65) have the same shape, while the stems (64) have different shapes. A method for manufacturing hook-and-loop fasteners, characterized by including the following:

2. In the thickness adjustment step, the pre-fastener body (60) or the deformable fastener body (70) is introduced between a pair of upper and lower thickness adjustment rollers (41, 42, 46, 47) and pressed in the thickness direction, and At least one of the upper thickness adjustment rollers (41, 46) and the lower thickness adjustment rollers (42, 47) is used to heat the pre-fastener body (60) or the deformable fastener body (70) to a temperature below the melting point of the synthetic resin. A method for manufacturing a hook-and-loop fastener according to claim 1, including the method described above.

3. In the molding process, a temporary base portion (51) is formed integrally with the multiple engagement elements (62) and supports the engagement elements (62), and After the molding process and before the thickness adjustment process, the pre-fastener body (60) is stretched along the machine direction (MD) to reduce the thickness dimension of the temporary base portion (51) and deform the temporary base portion (51) into the base portion (71), thereby forming the deformed fastener body (70). A method for manufacturing a hook-and-loop fastener according to claim 1 or 2, including the following:

4. In the thickness adjustment step, a greater pressing force is applied to the engaging element (62) located outside the central region in the orthogonal direction (CD) than to the engaging element (62) located in the central region in the orthogonal direction (CD). A method for manufacturing a hook-and-loop fastener according to any one of claims 1 to 3, including the above.

5. In the thickness adjustment step, by pressing in the thickness direction, the total thickness of the hook-and-loop fastener from the second surface of the base portion (71) to the top end of the engaging element (62) in the thickness direction is made uniform in the orthogonal direction (CD). A method for manufacturing a hook-and-loop fastener according to any one of claims 1 to 4, including the above.

6. In the thickness adjustment step, at least two types of engagement elements (62) having different stem diameters (75) in the central part of the stem portion (64) in the thickness direction are formed at different positions in the orthogonal direction (CD). A method for manufacturing a hook-and-loop fastener according to any one of claims 1 to 5, including the above.

7. In the thickness adjustment step, at least a first engaging element (62) is formed in the central region of the base portion (71) in the orthogonal direction (CD), and a second engaging element (62) is formed outside the central region in the orthogonal direction (CD), and the stem thickness (75) of the central part of the stem portion (64) in the thickness direction is thicker than that of the first engaging element (62). A method for manufacturing a hook-and-loop fastener according to any one of claims 1 to 6, including the above.

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