Hook-and-loop fastener and method for manufacturing the same

Abstract

A hook-and-loop fastener (1) of the present invention includes a base part (10) and a plurality of engaging elements (20), the base part (10) and the engaging elements (20) contain a thermoplastic resin including, at least partially, a plant-derived resin, the plant-derived resin has an MFR of 5 g / 10 min to 30 g / 10 min and a flexural modulus of 800 MPa to 2300 MPa, and an engaging head (23) has such a shape that at least a portion of the engaging head (23) protrudes outward from the upper edge of a stem portion (22) in a plan view of the engaging elements (20). This arrangement allows the hook-and-loop fastener (1) to have a plurality of engaging elements (20) that can engage with loop members or the like. This arrangement also enables a reduction in use of fossil resource-derived resins compared to the related art, thereby reducing the load on the environment.

Description

[Technical Field]

[0001] The present invention relates to a hook-and-loop fastener and a method for manufacturing the hook-and-loop fastener. [Background technology]

[0002] Hook-and-loop fasteners are now widely used in a wide variety of products, including those that are easily attached to the body, such as disposable diapers, diaper covers for infants, supporters for protecting the joints of the limbs, lumbar corsets (lumbar pain belts), gloves, etc. Furthermore, conventional hook-and-loop fasteners are generally made from synthetic resins derived from fossil resources.

[0003] In recent years, interest in various issues, including environmental problems, has grown, and efforts are being made to achieve the Sustainable Development Goals. As one of these efforts, the use of fossil-derived resins has been criticized for its greenhouse gas emissions, environmental pollution caused by waste after disposal, and the risk of fossil-derived resource depletion. Therefore, studies are underway to replace fossil-derived resins with plant-derived resins (sometimes called biomass-derived resins) or biodegradable resins made from renewable biological resources. Furthermore, it is estimated that the production capacity of plant-derived resins and biodegradable resins will increase year by year.

[0004] For example, Japanese Patent Publication No. 2014-533164 (Patent Document 1) discloses that bioplastics derived from renewable biomass, such as cellulose and biopolymers, may be used as materials for forming hook fasteners. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2014-533164 Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 lists bioplastics as an example of a material for hook fasteners, but does not provide any detailed information on the physical properties of bioplastics required to form the hook fasteners, the processing conditions for bioplastics, etc.

[0007] For example, it has also been considered to use a mixture of plant-derived or biodegradable resin and fossil resource-derived resin as the synthetic resin for forming the hook-and-loop fastener. However, in this case, due to differences in the physical properties of the plant-derived or biodegradable resin and the fossil resource-derived resin, simply mixing two different types of resins has not made it possible to form the engaging elements of the hook-and-loop fastener into an appropriate shape.

[0008] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a hook-and-loop fastener that can be formed using a plant-derived resin and has a plurality of engaging elements that can engage with a loop member, etc., and a manufacturing method for manufacturing the hook-and-loop fastener. [Means for solving the problem]

[0009] 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 provided on one surface of the base portion, each engaging element having a stem portion extending upward from the base portion and an engaging head portion integrally formed at the upper end of the stem portion, wherein the base portion and the engaging elements contain a thermoplastic resin, and the thermoplastic resin contains: 50 parts by weight of plant-based polyethylene and 50 parts by weight Petroleum-based polypropylene It consists of a mixture of 、 The aforementioned Plant-based polyethylene has a melt flow rate of 5 g / 10 min or more and 30 g / 10 min or less, and a flexural modulus of 800 MPa or more and 2300 MPa or less, Petroleum-based polypropylene has a melt flow rate of 5 g / 10 min or more and 60 g / 10 min or less, and a flexural modulus of 600 MPa or more and 2300 MPa or less, The plant-derived polyethylene and the petroleum-derived polypropylene have melt flow rates that are different from each other and flexural moduli that are different from each other, The engaging head is the entire periphery of the upper end of the stem portion In、 The stem portion has a shape that protrudes outward from the upper end thereof. The engaging head has an upwardly facing head top end surface, an outer peripheral side surface that slopes or curves downward from the outer peripheral edge of the head top end surface, and a head back surface that is disposed between the outer peripheral side surface and the upper end of the stem portion, and the back surface angle between the part of the head back surface that extends from the upper end of the stem portion and an imaginary line that extends downward from the upper end of the stem portion is 120° or less. It is a hook-and-loop fastener.

[0013] In the hook-and-loop fastener of the present invention, the engaging element is preferably provided with at least one minute claw portion that protrudes from the outer peripheral edge of the engaging head portion. In this case, it is preferable that the minute claws hang down from the outer peripheral edge of the engaging head toward the base.

[0014] Next, a method for manufacturing a hook-and-loop fastener provided by the present invention is a method for manufacturing a hook-and-loop fastener having a base portion and a plurality of engaging elements provided on one surface of the base portion, each engaging element having a stem portion extending upward from the base portion and an engaging head portion integrally formed at the upper end of the stem portion, wherein the method comprises: 50 parts by weight of plant-based polyethylene and, 50 parts by weight of petroleum-based polypropylene a primary molding step of molding a primary molded body having the base portion and a plurality of primary elements provided on one surface of the base portion by melting and supplying a material containing a thermoplastic resin consisting of a mixture of However, the entire circumference of the upper end of the stem portion and a secondary molding step of molding the engaging element that protrudes outward from the upper end of the stem portion, 、 The melt flow rate is 5 g / 10 min or more and 30 g / 10 min or less, and the flexural modulus is 800 MPa or more and 2300 MPa or less. Plant-based polyethylene Using 、 The melt flow rate is 5 g / 10 min or more and 60 g / 10 min or less, and the flexural modulus is 600 MPa or more and 2300 MPa or less. Petroleum-based polypropylene Using The plant-derived polyethylene and the petroleum-derived polypropylene have melt flow rates different from each other and bending moduli different from each other. The secondary forming step includes using a secondary forming device having at least an upper roller equipped with a heating source, and bringing the upper roller into contact with the primary element to heat the primary element and press it from above. 、The heating temperature of the upper roller is set to a temperature 18°C ​​lower than the weighted average of the melting points of the synthetic resins contained in the thermoplastic resin. and the engaging head has an upwardly facing head top end surface, an outer peripheral side surface that is inclined or curved downward from the outer peripheral edge of the head top end surface, and a head back surface that is disposed between the outer peripheral side surface and the upper end of the stem portion, and the back surface angle between the part of the head back surface that extends from the upper end of the stem portion and an imaginary line that extends downward from the upper end of the stem portion is 120° or less. The manufacturing method includes:

[0015] The method for manufacturing a hook-and-loop fastener of the present invention preferably includes setting the heating temperature of the upper roller in the secondary molding process to a temperature that is at least 35°C lower than the weighted average of the melting points of the synthetic resins contained in the thermoplastic resin.

[0018] Furthermore, the manufacturing method of the present invention preferably includes, in the primary molding step, molding the primary molded body using a die wheel comprising an outer cylindrical body provided with a plurality of through holes extending from the outer peripheral surface to the inner peripheral surface, and an inner cylindrical body arranged in close contact with the inner peripheral surface of the outer cylindrical body, the outer peripheral surface of the inner cylindrical body being provided with a plurality of recesses, and the outer peripheral edges of at least some of the through holes in the inner peripheral surface of the outer cylindrical body having portions that overlap the recesses of the inner cylindrical body.

[0019] In this case, the manufacturing method of the present invention preferably includes, in the primary molding step, molding the primary element having at least a primary stem portion formed by the through hole of the outer cylinder and a primary micro-claw portion formed by the recess of the inner cylinder, and, in the secondary molding step, forming a micro-claw portion protruding from the engaging head from the primary micro-claw portion. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a hook-and-loop fastener formed using a plant-derived resin and having a plurality of engaging elements that can engage with a loop member or the like, and a method for manufacturing the hook-and-loop fastener. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view showing a hook-and-loop fastener according to an embodiment of the present invention. [Figure 2]2 is a front view of the engaging elements of the hook-and-loop fastener shown in FIG. 1 as seen from the machine direction. [Figure 3] FIG. 2 is a schematic diagram for explaining a manufacturing apparatus for manufacturing the hook-and-loop fastener shown in FIG. [Figure 4] 4 is a perspective view schematically showing an outer cylindrical body and an inner cylindrical body arranged in a primary molding device of the manufacturing apparatus shown in FIG. 3. FIG. [Figure 5] FIG. 2 is a perspective view schematically showing a primary molded body molded in a primary molding step. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that 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, in the following examples, the number, size (thickness and height), and formation density of the engaging elements provided on the base portion of the hook-and-loop fastener are not particularly limited and can be modified.

[0023] Fig. 1 is a perspective view showing a hook-and-loop fastener according to this embodiment, and Fig. 2 is a front view of an engaging element of the hook-and-loop fastener as seen from the machine direction. In the following description, the front-rear direction is the length direction of the hook-and-loop fastener 1 and the primary molded body 30 which are molded in a long length. The front-rear direction is also the direction along the machine direction MD in which the hook-and-loop fastener 1 or the primary molded body 30 is transported in the manufacturing process of the hook-and-loop fastener 1.

[0024] The left-right direction refers to the width direction that is perpendicular to the length direction and that runs along the flat upper surface (first surface) of the base portion 10 of the hook-and-loop fastener 1. In this case, the left-right direction and width direction are directions that run along the cross direction CD that is perpendicular to the machine direction MD. The vertical direction is the height direction (or thickness direction of the base part 10) along a direction perpendicular to the flat upper surface of the base part 10, 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 20 protrudes from the base part 10 is the upper side in the vertical direction, and the opposite side is the lower side.

[0025] The hook-and-loop fastener 1 according to this embodiment is manufactured using a manufacturing apparatus 40 having a primary molding apparatus 50 and a heat pressing apparatus (secondary molding apparatus) 60 shown in Fig. 3, as will be described later, in a rectangular shape that is long in the machine direction MD of the manufacturing apparatus 40 when viewed from above. The length dimension (dimension in the machine direction MD) and width dimension (dimension in the cross direction CD) of the hook-and-loop fastener 1 are not particularly limited and can be changed as desired by cutting the hook-and-loop fastener 1, for example. The hook-and-loop fastener 1 may also have a shape other than rectangular when viewed from above.

[0026] The hook-and-loop fastener 1 of this embodiment is formed from a thermoplastic resin containing a plant-derived resin. Specifically, the thermoplastic resin forming the hook-and-loop fastener 1 of this embodiment is a mixture of a plant-derived resin and a fossil resource-derived resin. Different types of synthetic resins are used for the plant-derived resin and the fossil resource-derived resin. For example, plant-derived polyethylene is preferably used as the plant-derived resin. In recent years, the production and supply of plant-derived polyethylene has become stable, making it relatively easy to obtain. Furthermore, development of plant-derived polyethylene has progressed, and various types with different densities, shapes, etc. are sold. This allows for greater freedom in material selection. Petroleum-derived polypropylene is preferably used as the fossil resource-derived resin. Note that natural gas-derived polypropylene may be used instead of petroleum-derived polypropylene.

[0027] Here, plant-derived resins are synthetic resins obtained from biological resources and are sometimes called biomass plastics. Whether a synthetic resin is plant-derived or fossil-derived can be determined by performing measurements based on ASTM D6866. Furthermore, the proportion of plant-derived resin in the synthetic resin can also be determined by such measurements.

[0028] In a thermoplastic resin blend of plant-derived polyethylene and petroleum-derived polypropylene, the plant-derived polyethylene is contained in an amount of 25 parts by weight or more but less than 100 parts by weight, assuming that the thermoplastic resin blend is 100 parts by weight. The petroleum-derived polypropylene is contained in an amount of more than 0 parts by weight but not more than 75 parts by weight. For example, in this embodiment, the thermoplastic resin forming the hook-and-loop fastener 1 contains 50 parts by weight of plant-derived polyethylene and 50 parts by weight of petroleum-derived polypropylene.

[0029] In the present invention, the plant-derived resin may be a resin other than plant-derived polyethylene. The fossil resource-derived resin may be a resin other than petroleum-derived polypropylene. Furthermore, the thermoplastic resin forming the hook-and-loop fastener 1 may be formed from plant-derived resin alone (100 parts by weight of plant-derived resin) rather than a mixture of plant-derived resin and fossil resource-derived resin.

[0030] Regarding the material of the hook-and-loop fastener 1, the plant-derived resin (in this embodiment, plant-derived polyethylene) contained in the thermoplastic resin has a melt flow rate (hereinafter sometimes abbreviated as MFR) of 5 g / 10 min to 30 g / 10 min and a flexural modulus of 800 MPa to 2300 MPa. The fossil resource-derived resin (in this embodiment, petroleum-derived polypropylene) contained in the thermoplastic resin has an MFR of 5 g / 10 min to 60 g / 10 min and a flexural modulus of 600 MPa to 2300 MPa. The MFR ranges of the plant-derived resins described above are shown as values ​​when the measurement temperature is 190°C. The MFR ranges of the fossil resource-derived resins described above are shown as values ​​when the measurement temperature is 230°C.

[0031] The hook-and-loop fastener 1 of this embodiment has a thin, flat base portion 10 and a plurality of engaging elements 20 provided on the upper surface of the base portion 10. The base portion 10 is formed long along the machine direction MD in the manufacturing process of the hook-and-loop fastener 1. The base portion 10 has a predetermined thickness that provides appropriate strength. The base portion 10 has a flat upper surface (first surface) and a flat lower surface (second surface) arranged on the opposite side of the upper surface, and the upper and lower surfaces of the base portion 10 are formed parallel to each other.

[0032] The plurality of engaging elements 20 are regularly aligned in a staggered pattern on the upper surface of the base portion 10. Specifically, the engaging elements 20 are arranged at a constant pitch (interval) along the front-rear direction to form an engaging element row 21. The plurality of engaging element rows 21 are arranged at constant intervals in the left-right direction. The plurality of engaging elements 20 are arranged alternately or in a zigzag pattern between adjacent engaging element rows 21 in the left-right direction, with the positions of the engaging elements 20 shifted by ½ pitch in the front-rear direction. Note that in the present invention, the arrangement of the engaging elements 20 is not particularly limited; for example, the plurality of engaging elements 20 may be arranged in a grid pattern aligned in the front-rear direction and the left-right direction, or may be arranged randomly.

[0033] Each engaging element 20 has a stem portion 22 rising from the upper surface of the base portion 10, a disk-shaped or dish-shaped engaging head 23 integrally formed at the upper end of the stem portion 22, and two small claw portions 24 that protrude slightly outward from the outer peripheral edge of the engaging head 23.

[0034] The stem portion 22 protrudes upward from the upper surface of the base portion 10. The stem portion 22 has a truncated conical shape, or an approximately truncated conical shape close to a truncated cone, in which the area of ​​a cross section perpendicular to the up-down direction gradually increases as it approaches the base portion 10. Note that in the present invention, the shape of the stem portion 22 is not limited to a truncated cone or an approximately truncated cone, and may be, for example, a truncated pyramid such as a square pyramid, a cylinder, a prism such as a square prism, or a shape close to any of these.

[0035] The engaging head 23 is integrally formed on the stem portion 22 via a boundary portion 25. In this case, the boundary portion 25 between the stem portion 22 and the engaging head 23 can also be referred to as the bent portion of the engaging element 20 or the upper end of the stem portion 22. The engaging head 23 has a relatively small thickness (dimension in the vertical direction), and is circular in a plan view of the engaging element 20 seen from above.

[0036] In a plan view of the engaging element 20, the circle formed by the outer periphery of the engaging head 23 has a larger diameter than the circle formed by the boundary portion 25, and also includes the circle of the boundary portion 25 radially inward. In this embodiment, the engaging head 23 has a shape that protrudes from the boundary portion 25 toward the outside in the radial direction of the engaging head 23 around the entire circumference of the boundary portion 25. Note that in the present invention, the engaging head may be formed in a shape in which only a portion of the engaging head protrudes from the boundary portion toward the outside in the radial direction of the engaging head.

[0037] 2, the engaging head 23 has an upwardly facing head top surface 23a, an outer peripheral side surface 23b that slopes or curves downward from the outer peripheral edge of the head top surface 23a, and a head back surface 23c that extends from the boundary portion 25 toward the outer peripheral side surface 23b. The head top surface 23a of the engaging head 23 has a flat surface that is arranged parallel or approximately parallel to the upper surface of the base portion 10. The head back surface 23c is arranged between the outer peripheral side surface 23b of the engaging head 23 and the boundary portion 25. The outer peripheral side surface 23b of the engaging head 23 is formed over the entire circumferential direction of the engaging head 23 between the head top surface 23a and the head back surface 23c.

[0038] The head back surface 23c is disposed on the back side (opposite side in the vertical direction) of the head top end surface 23a of the engaging head 23 so as to face the base portion 10. Furthermore, the head back surface 23c is formed as a flat surface or a substantially flat surface when the engaging element 20 is viewed from a direction perpendicular to the vertical direction. The head back surface 23c may be formed as a curved surface or a substantially curved surface when the engaging element 20 is viewed from a direction perpendicular to the vertical direction. The head back surface 23c is formed in a donut-like or ring-like shape that surrounds the stem portion 22.

[0039] When the engaging element 20 is viewed from a direction perpendicular to the vertical direction (see FIG. 2), an imaginary line 26 extending downward from the boundary 25 of the engaging element 20 along the vertical direction is defined as the back surface angle θ, which is the angle between the portion of the head back surface 23c extending from the boundary 25 and the imaginary line 26. The engaging head 23 of this embodiment has a shape in which the back surface angle θ of the head back surface 23c is 120° or less.

[0040] By setting the back surface angle θ to 120° or less (preferably 90° or less), it is possible to make it easier for the loop of the loop member such as a nonwoven fabric to be caught on the back side of the engaging head 23. In addition, it is possible to make it easier for the loop caught on the engaging head 23 to be held, and to prevent the loop from easily coming off the engaging element 20. This makes it easier for the hook-and-loop fastener 1 to have high engagement strength (peel strength) with the loop member. In addition, it is preferable that the back surface angle θ is 70° or more. This makes it easier for the loop of the loop member to slip into the back side of the engaging head 23.

[0041] In the present invention, there is no particular limitation on the back surface angle θ of the engaging element 20. Furthermore, the engaging element 20 preferably has a shape in which the back surface angle θ is 120° or less in at least a part of the engaging head 23, and more preferably has a shape in which the back surface angle θ is 120° or less over the entire circumference of the engaging head 23.

[0042] Each engaging element 20 is provided with a pair of left and right microclaws 24 that protrude outward from the outer peripheral edge of the engaging head 23. The left and right microclaws 24 are arranged in a point-symmetrical positional relationship with respect to each other in a plan view of the engaging element 20, and protrude outward from the engaging head 23 in the radial direction of the engaging head 23. In the case of this embodiment, the left and right microclaws 24 protrude in opposite directions from the engaging head 23 along the left-right direction (diameter direction CD).

[0043] Furthermore, in the engaging head 23, the outer peripheral edge of the head top surface 23a has an area connected to the microclaw portions 24 and an area connected to the outer peripheral side surface 23b. In the area of ​​the head top surface 23a connected to the microclaw portions 24, the head top surface 23a is connected to the microclaw portions 24, and the microclaw portions 24 are connected to the head back surface 23c formed below it. The head back surface 23c is connected to the outer peripheral edge of the stem portion 22 at the boundary portion 25 around its entire circumference. In this way, as long as the outer peripheral edge of the engaging head 23 has areas where the microclaw portions 24 are formed and areas where the microclaw portions 24 are not formed, the number of microclaw portions 24 is not limited.

[0044] 2, each of the left and right microclaw portions 24 has a shape that hangs diagonally downward from the outer peripheral edge of the engaging head 23 toward the tip in the protruding direction so as to approach the base portion 10. Each microclaw portion 24 is formed to a minute size such that the claw width dimension (the distance between the claw-side wall surfaces) at the base end portion connected to the engaging head 23 of the microclaw portion 24 is 1 / 2 or less, preferably 1 / 3 or less, and more preferably 1 / 5 or less of the length of the boundary portion 25 when the engaging element 20 is viewed from a direction perpendicular to the up-down direction.

[0045] By providing the above-mentioned microclaw portions 24 on each engaging element 20, when a loop member is engaged with the hook-and-loop fastener 1, the loop engaged with the engaging element 20 is caught on the microclaw portions 24, making it more difficult for the loop to come off the engaging element 20. Furthermore, by forming the microclaw portions 24 smaller than the engaging head portions 23, the effect of the placement of the microclaw portions 24 on the feel or sensation on the upper surface side of the hook-and-loop fastener 1 can be kept small.

[0046] Next, a method for manufacturing the hook-and-loop fastener 1 of the above-described embodiment will be described. The hook-and-loop fastener 1 shown in Figures 1 and 2 is manufactured using a manufacturing apparatus 40 shown in Figure 3. This manufacturing apparatus 40 has a primary molding apparatus 50 that performs a primary molding step, and a heat pressing apparatus (secondary molding apparatus) 60 that performs a secondary molding step in which the primary molded body 30 formed in the primary molding step is pressed and molded.

[0047] The primary molding device 50 has a die wheel 51 that is driven to rotate in one direction (counterclockwise in the drawing), a supply nozzle section 55 that is arranged opposite the peripheral surface of the die wheel 51 and that continuously extrudes (or pours out) molten synthetic resin material, and a pickup roller 56 that is arranged downstream of the supply nozzle section 55 in the direction of rotation of the die wheel 51.

[0048] The die wheel 51 includes a cylindrical outer cylinder (outer sleeve) 52 that serves as a die, a cylindrical inner cylinder (inner sleeve) 53 that is disposed in close contact with the inside of the outer cylinder 52, and a rotation drive roller 54 that rotates the outer cylinder 52 and the inner cylinder 53 in one direction. A cooling jacket (not shown) that circulates a cooling liquid is provided inside the rotation drive roller 54.

[0049] The outer cylindrical body 52 has a plurality of through holes 52a that penetrate from the outer peripheral surface to the inner peripheral surface of the outer cylindrical body 52, and serve as cavities for molding the primary stem portion 32 (described later) of the primary molded body 30. The positions at which the plurality of through holes 52a are formed correspond to the positions at which the engaging elements 20 are disposed in the manufactured hook-and-loop fastener 1. Each of the through holes 52a has the shape of a truncated cone or an approximately truncated cone, with the circle on the outer peripheral surface of the outer cylindrical body 52 being larger than the circle on the inner peripheral surface of the outer cylindrical body 52.

[0050] A plurality of grooves (recesses) 53a are formed in the outer peripheral surface of the inner cylinder 53. Each groove 53a is linearly recessed along a direction parallel to the central axis of the inner cylinder 53 (the cross direction CD) and is sized to allow the flow of molten synthetic resin. The grooves 53a are formed at regular intervals along the circumferential direction of the inner cylinder 53 (the machine direction MD). At least some of the grooves 53a of the inner cylinder 53 are arranged so as to intersect with the outer peripheral edges of the through holes 52a formed in the inner peripheral surface of the outer cylinder 52 when the die wheel 51 is assembled. Note that a plurality of recesses having shapes and sizes different from the grooves 53a may be formed in the outer peripheral surface of the inner cylinder 53.

[0051] Alternatively, the die wheel 51 may not include the inner cylinder 53, and the outer cylinder 52 may be directly attached to the rotation drive roller 54. In this case, the inner peripheral surface of the outer cylinder 52 has a recess connected to the outer peripheral edge of the through hole 52a. The recess is recessed to a size that allows the molten synthetic resin to flow into it. Alternatively, a recess may be formed on the surface of the rotation drive roller 54 that comes into contact with the outer cylinder 52. The recess of the rotation drive roller 54 connects to the outer peripheral edge of the through hole 52a in the inner peripheral surface of the outer cylinder 52 and allows the molten synthetic resin to flow into it.

[0052] The pickup roller 56 has a pair of upper and lower clamping rollers 57 and 58 that clamp and pull the primary molded body 30 formed on the outer circumferential surface of the die wheel 51. The outer circumferential surfaces of the upper and lower clamping rollers 57 and 58 are each provided with a surface layer (not shown) made of an elastomer such as polyurethane elastomer.

[0053] The heating and pressing device 60 has a pair of upper and lower pressing rollers (calendar rollers) 61, 62 arranged downstream of the pickup roller 56. The upper pressing roller 61 and the lower pressing roller 62 are arranged facing each other with a predetermined gap between them. The gap between the upper pressing roller 61 and the lower pressing roller 62 can be adjusted by a height adjustment means (not shown).

[0054] The upper pressure roller 61 is provided with an internal heating source (not shown), and is configured so that the surface temperature (heating temperature) of the upper pressure roller 61 can be controlled, that is, so that the heating temperature of the upper pressure roller 61 can be set to a required temperature. In the present invention, the heating and pressing device 60 only needs to have an upper roller that comes into contact with the primary element 31 of the primary molded body 30 as described below and applies heat and pressure to at least a portion of the primary element 31, and the structure of the heating and pressing device 60 is not particularly limited.

[0055] When manufacturing the hook-and-loop fastener 1 using the manufacturing apparatus 40 having the primary molding apparatus 50 and the heating and pressing apparatus 60 as described above, first, a primary molding step is performed in which the primary molded body 30 is formed using the primary molding apparatus 50. In this primary molding step, a molten material containing a thermoplastic resin is continuously supplied from the supply nozzle portion 55 toward the outer circumferential surface of the rotating die wheel 51.

[0056] In the primary molding step of this embodiment, a material containing a thermoplastic resin formed from a mixture of a plant-derived resin and a fossil resource-derived resin is used as the feed material fed from the feed nozzle portion 55 to the die wheel 51. To explain in detail the thermoplastic resin contained in the feed material, in this embodiment, as described above, plant-derived polyethylene is used as the plant-derived resin forming the thermoplastic resin, and petroleum-derived polypropylene is used as the fossil resource-derived resin. In this embodiment, when the thermoplastic resin is 100 parts by weight, the thermoplastic resin is formed from 50 parts by weight of plant-derived polyethylene and 50 parts by weight of petroleum-derived polypropylene.

[0057] In this embodiment, the blending ratio of plant-derived polyethylene and petroleum-derived polypropylene is not limited and can be changed. When changing the blending ratio of the resins, the blending ratio of plant-derived polyethylene is preferably changed within a range of 25 parts by weight or more but less than 100 parts by weight. The blending ratio of petroleum-derived polypropylene is preferably changed within a range of more than 0 parts by weight but not more than 75 parts by weight.

[0058] In this embodiment, the material forming the hook-and-loop fastener 1 may contain additives such as lubricants and pigments in addition to the thermoplastic resin. The MFR of the plant-derived resin and the MFR of the fossil resource-derived resin may be adjusted by using additives. When additives are used, the additives are preferably contained in the thermoplastic resin in a proportion of 10 parts by weight or less, based on 100 parts by weight of the thermoplastic resin.

[0059] In this case, the plant-derived polyethylene forming the thermoplastic resin has an MFR of 5 g / 10 min to 30 g / 10 min and a flexural modulus of 800 MPa to 2300 MPa, while the petroleum-derived polypropylene has an MFR of 5 g / 10 min to 60 g / 10 min and a flexural modulus of 600 MPa to 2300 MPa.

[0060] Since the plant-derived polyethylene has an MFR of 5 g / 10 min or more and the petroleum-derived polypropylene has an MFR of 5 g / 10 min or more, when the upper end of the primary element 31 is heated and pressed in the secondary molding step described below, a portion of the primary element 31 can be softened and easily deformed at a predetermined heating temperature. Furthermore, this makes it easier to form the microclaws 24 on the outer peripheral edge of the engaging head 23.

[0061] Since the MFR of the plant-derived polyethylene is 30 g / 10 min or less and the MFR of the petroleum-derived polypropylene is 60 g / 10 min or less, sudden deformation of the primary element 31 is suppressed when the primary element 31 is heated and pressed in the secondary molding process, and the shape of the engaging element 20 can be stabilized.

[0062] Since the plant-derived polyethylene has a flexural modulus of 800 MPa or more and the petroleum-derived polypropylene has a flexural modulus of 600 MPa or more, it is possible to prevent the primary element 31 from being suddenly deformed during the secondary molding process and stabilize the shape of the engaging element 20. Furthermore, since the rigidity of the engaging element 20 can be appropriately ensured, it is possible to prevent a decrease in the engaging strength (peel strength) of the hook-and-loop fastener 1 due to the rigidity of the engaging element 20.

[0063] Since the plant-derived polyethylene has a flexural modulus of 2300 MPa or less and the petroleum-derived polypropylene has a flexural modulus of 2300 MPa or less, the primary element 31 can be appropriately and quickly deformed in the secondary molding process, thereby stably forming the engaging element 20 so that the back surface angle θ of the engaging head 23 falls within the above range.

[0064] In the primary molding process using the primary molding device 50, a molten material containing the thermoplastic resin described above is continuously supplied from a supply nozzle 55 to form a primary molded article 30, as shown in FIG. 5, in which multiple primary elements 31 (sometimes called provisional elements) protrude from the upper surface of a base 10. The material supplied from the supply nozzle 55 is heated to a temperature capable of melting both the plant-derived polyethylene and the petroleum-derived polypropylene. The molten material is then supplied to a die wheel 51, whereby a base 10 is continuously formed between the supply nozzle 55 and the die wheel 51 along the machine direction MD. Furthermore, while the base 10 is being molded, multiple primary elements 31 are integrally molded onto the base 10 by the outer cylindrical body 52 and inner cylindrical body 53 of the die wheel 51. The primary molding device may be configured, for example, to supply molten synthetic resin material from the supply nozzle toward the gap between two opposing die wheels. In this case, the base 10 is formed between a pair of die wheels, and the primary elements are formed in cavities provided in one of the die wheels.

[0065] The primary molded body 30 molded by the primary molding device 50 has a thin plate-like base portion 10 and a plurality of primary elements 31 protruding from the upper surface of the base portion 10. The base portion 10 of the primary molded body 30 becomes the base portion 10 of the hook-and-loop fastener 1 as is. The primary elements 31 are deformed into engaging elements 20 by being press-molded in the secondary molding process. Each primary element 31 has a truncated cone or approximately truncated cone-shaped primary stem portion 32 rising from the base portion 10, a rod-shaped rib portion 33 bulging upward from the upper surface of the primary stem portion 32, and two protrusions (primary micro-claw portions) 34 formed integrally with the rib portion 33 and protruding outward from the primary stem portion 32. Note that the primary element 31 does not necessarily have to have the rod-shaped rib portion 33 bulging upward from the upper surface of the primary stem portion 32. In this case, the primary element 31 has two protrusions (primary micro-claws) 34 that protrude outward from the outer periphery of the primary stem portion 32 at the upper end of the primary stem portion 32 .

[0066] In the primary element 31, the rib portion 33 and the protrusions 34 are formed by the synthetic resin flowing from the through hole 52a of the outer cylinder 52 into the groove 53a provided in the inner cylinder 53 during the primary molding process, and then flowing along the groove 53a beyond the through hole 52a. In this case, the rib portion 33 is formed locally on the upper surface of the primary stem portion 32 along the orthogonal direction CD. The two protrusions 34 protrude outward from both ends of the rib portion 33 from the primary stem portion 32.

[0067] In the primary molding step, a molten material containing a thermoplastic resin is supported on the outer circumferential surface of the die wheel 51 and rotated halfway while being cooled, thereby forming the above-mentioned primary molded body 30. Thereafter, the primary molded body 30 is continuously peeled off from the outer circumferential surface of the die wheel 51 by a pickup roller 56.

[0068] Next, the primary molded body 30 peeled off from the die wheel 51 is transported toward the heating and pressing device 60 where the secondary molding process is performed, and is introduced between the upper pressing roller 61 and the lower pressing roller 62 of the heating and pressing device 60.

[0069] In this secondary molding step, the base portion 10 of the primary molded body 30 is supported from below by a lower pressure roller 62. In addition, the upper pressure roller 61 is rotated and brought into contact with the upper end portion of each primary element 31, so that the upper pressure roller 61 heats and softens at least the upper end portion of each primary element 31 and presses it from above. As a result, the upper end portion of the primary stem portion 32, the rib portion 33, and the protrusion portion 34 of the primary element 31 are crushed and thermally deformed, forming the engaging head portion 23 and the microclaw portion 24.

[0070] At this time, the heating temperature of the upper pressure roller 61 is set to a temperature that is at least 35°C lower than the weighted average of the melting points of the synthetic resins contained in the thermoplastic resin (hereinafter, sometimes referred to as the weighted average temperature) and at most 18°C ​​lower than the weighted average temperature. That is, in the secondary molding step of this embodiment, the heating temperature of the upper pressure roller 61 is set to an appropriate temperature depending on the components of the material supplied from the supply nozzle unit 55.

[0071] For example, if a thermoplastic resin contains 50 parts by weight of plant-derived polyethylene (melting point of 131°C) and 50 parts by weight of petroleum-derived polypropylene (melting point of 168°C), as described above, the weighted average of the melting points of each thermoplastic resin will be 149.5°C. Because the melting point of plant-derived polyethylene is lower than that of petroleum-derived polypropylene, if the proportion of plant-derived polyethylene in the thermoplastic resin is higher than the proportion of petroleum-derived polypropylene, the weighted average temperature will be lower than 149.5°C.

[0072] For this reason, the heating temperature of the upper pressure roller 61 is set to 114.5°C or higher and 131.5°C or lower. Specifically, the heating temperature of the upper pressure roller 61 in this embodiment is set to 118°C (see Example 1 described below). Here, the heating temperature of the upper pressure roller 61 is the temperature at the roller surface (outer circumferential surface) of the upper pressure roller 61, which is heated by a heat source (not shown). Note that when calculating the weighted average temperature of the melting point of the thermoplastic resin, the melting points of additive substances contained in an amount of 10 parts by weight or less, assuming that the thermoplastic resin is 100 parts by weight, are not taken into consideration. The melting point of each thermoplastic resin can be calculated by DSC measurement.

[0073] By setting the heating temperature of the upper pressure roller 61 to a temperature 35°C lower than the weighted average of the melting points of the synthetic resins or higher, the upper end of the primary element 31 can be appropriately heated, allowing the engaging head 23 and the microclaw 24 to be smoothly molded. Furthermore, the back surface angle θ of the head back surface 23c of the engaging head 23 can be stably set to 120° or less. By setting the heating temperature of the upper pressure roller 61 to a temperature 18°C ​​lower than the weighted average of the melting points of the synthetic resins or lower, the primary element 31 is prevented from being overheated when it comes into contact with the upper pressure roller 61, allowing the engaging element 20 having the engaging head 23 to be stably molded.

[0074] In addition, in this embodiment, the material used for the hook-and-loop fastener 1 is a mixture of plant-derived polyethylene whose MFR and flexural modulus are adjusted to fall within a predetermined range, and petroleum-derived polypropylene whose MFR and flexural modulus are adjusted to fall within a predetermined range, thereby ensuring the appropriate strength of the engaging element 20.

[0075] By carrying out the secondary molding process described above, a hook-and-loop fastener 1 having a plurality of engaging elements 20 as shown in Figures 1 and 2 is manufactured. The hook-and-loop fastener 1 long in the machine direction MD obtained by carrying out the secondary molding process is wound up in a roll on a collection roller or the like and collected. Alternatively, the hook-and-loop fastener 1 may be transported to a cutting section (not shown) and collected after being cut into a predetermined width and / or length at the cutting section.

[0076] In the hook-and-loop fastener 1 of this embodiment, a plurality of engaging elements 20, each having at least a stem portion 22 and an engaging head portion 23, are stably formed, thereby enabling stable engagement of loop members. Furthermore, since the hook-and-loop fastener 1 contains plant-derived polyethylene, which is a plant-derived resin, the use of resins derived from fossil resources can be reduced, thereby easing the burden on the environment. Furthermore, effects such as a reduction in greenhouse gas emissions and the suppression or prevention of environmental pollution can be expected. In particular, by containing petroleum-derived polypropylene in addition to plant-derived polyethylene in the hook-and-loop fastener 1, the hook-and-loop fastener 1 can have an appropriate strength for use and can also suppress an increase in the manufacturing cost of the hook-and-loop fastener 1.

[0077] Furthermore, in the hook and loop fastener 1 of this embodiment, the heating temperature of the upper pressure roller 61 in the secondary molding step of the manufacturing process is set to a temperature that is 18°C ​​lower than the weighted average of the melting points of the synthetic resins. This makes it possible to stably form the engaging elements 20 having the engaging heads 23 and the microclaws 24 even if the thermoplastic resin contains plant-derived polyethylene. Therefore, the hook and loop fastener 1 of this embodiment can firmly engage the loop members.

[0078] Furthermore, in the hook-and-loop fastener 1 of this embodiment, the heating temperature of the upper pressure roller 61 in the secondary molding step of the manufacturing process is set to a temperature that is 35°C lower than the weighted average of the melting points of each synthetic resin. This allows the primary elements 31 to be stably thermally deformed in the secondary molding step to form the engaging elements 20. Furthermore, the back surface angle θ of the engaging head 23 can be stably kept at 120° or less, effectively increasing the engagement strength of the hook-and-loop fastener 1 with the loop member. [Example]

[0079] The present invention will be described in more detail below with reference to examples.

[0080] (Examples 1 to 3) In Examples 1 to 3, hook-and-loop fasteners 1 were manufactured using the manufacturing apparatus 40 described in the above embodiment. In Examples 1 to 3, a material containing 50 parts by weight of plant-derived polyethylene, 50 parts by weight of petroleum-derived polypropylene, and 4 parts by weight of pigment, relative to 100 parts by weight of thermoplastic resin, was used as the feed material supplied from the feed nozzle 55 to the die wheel 51. The melting points of the plant-derived polyethylene and petroleum-derived polypropylene used in Examples 1 to 3 were calculated by DSC measurement (DSC7000X, manufactured by Hitachi High-Tech Science).

[0081] In this case, the plant-derived polyethylene used had an MFR of 20 g / 10 min (measured at 190°C), a flexural modulus of 1250 MPa, and a melting point of 131°C. The petroleum-derived polypropylene had an MFR of 10 g / 10 min (measured at 230°C), a flexural modulus of 2000 MPa, and a melting point of 168°C. In addition, a white pigment whose main component was polypropylene and also contained titanium oxide was used as the pigment.

[0082] In addition, Table 1 below shows the components of each material in Examples 1 to 3, as well as the "weighted average temperature of the melting point of the synthetic resin" for each material, the "heating temperature of the upper pressure roller 61" in the secondary molding process, and the results of calculating the "difference between the calculated weighted average temperature and the heating temperature of the upper pressure roller 61."

[0083] As shown in Table 1, in Examples 1 to 3, the primary molding step was carried out using the same material to produce the primary molded body 30. Thereafter, the obtained primary molded body 30 was subjected to the secondary molding step by setting the heating temperature of the upper pressure roller 61 to different temperatures, thereby producing each of the hook-and-loop fasteners 1 of Examples 1 to 3.

[0084] After manufacturing each hook-and-loop fastener 1, the obtained hook-and-loop fastener 1 was cut in a direction perpendicular to the machine direction MD, and the engaging elements 20 of each hook-and-loop fastener 1 were photographed from one side (front side) in the machine direction MD. Furthermore, from the photographed images of the engaging elements 20, the shape of each engaging element 20 was observed and the back surface angle θ of the engaging head 23 was measured. The values ​​of the back surface angle θ measured in Examples 1 to 3 are shown in Table 1 below.

[0085] (Comparative Example) As a comparative example, a primary molded body 30 was produced by carrying out a primary molding process using the same material as in Examples 1 to 3. Thereafter, the obtained primary molded body 30 was subjected to a secondary molding process in which the heating temperature of the upper pressure roller 61 was set to 133°C, which is higher than 131.5°C (= "a temperature 18°C ​​lower than the weighted average temperature of the melting point of the synthetic resin"), thereby producing a hook-and-loop fastener of the comparative example. After the surface fastener of the comparative example was manufactured, the shape of the engaging elements 20 was observed in the same manner as in Examples 1 to 3 described above.

[0086] [Table 1]

[0087] As a result of observing the shape of each engaging element 20 in Examples 1 to 3, it was confirmed that in the hook-and-loop fasteners 1 of Examples 1 to 3, in which the heating temperature of the upper pressure roller 61 in the secondary molding step was set to 131.5°C (= "a temperature 18°C ​​lower than the weighted average temperature of the melting point of the synthetic resin") or lower, the engaging element 20 has a substantially truncated conical stem portion 22, an engaging head 23 integrally formed at the upper end of the stem portion 22, and two minute claw portions 24 protruding from the outer peripheral surface of the engaging head 23, and that the engaging head 23 is formed in a shape such that at least a portion of the engaging head 23 protrudes outward from the upper end of the stem portion 22 in a plan view of the engaging element 20. Therefore, it was found that each of the hook-and-loop fasteners 1 of Examples 1 to 3 can smoothly engage with a loop member, and further, that when the hook-and-loop fastener 1 is used in a disposable diaper product, for example, the hook-and-loop fastener 1 can ensure an engagement strength with the loop member suitable for use in the product.

[0088] Furthermore, it was confirmed that in the hook-and-loop fasteners 1 of Examples 1 and 2, in which the heating temperature of the upper pressure roller 61 was set to a temperature higher than 114.5°C (= "a temperature 35°C lower than the weighted average temperature of the melting point of the synthetic resin"), the back-surface angle θ of the engaging elements 20 was 120° or less. Therefore, it was found that the hook-and-loop fasteners 1 of Examples 1 and 2 had a higher engagement strength than the hook-and-loop fastener 1 of Example 3, in which the back-surface angle θ was greater than 120°.

[0089] On the other hand, it was confirmed that in the hook-and-loop fastener 1 of the comparative example, in which the heating temperature of the upper pressure roller 61 was set to a temperature higher than 131.5°C, the engaging head 23, which protrudes outward from the upper end of the stem portion 22, was not properly formed. For this reason, it was found that the hook-and-loop fastener 1 of the comparative example was unable to engage with the loop member, or, even if it did engage, did not provide an engaging strength suitable for use in disposable diaper products. [Explanation of symbols]

[0090] 1 hook-and-loop fastener 10 Base 20 Engagement element 21 Engagement element array 22 Stem 23 Engagement head 23a Top surface of head 23b Outer side 23c Back side of head 24 Minute claw part 25 Boundary 26 Virtual Line 30 Primary molded body 31 Primary element 32 Primary stem 33 Rib section 34 Projection part (primary minute claw part) 40 Manufacturing equipment 50 Primary forming equipment 51 Die Wheel 52 outer cylinder (outer sleeve) 52a through hole 53 Inner cylinder (inner sleeve) 53a groove (recess) 54 Rotation drive roller 55 Supply nozzle part 56 Pickup roller 57 Upper clamping roller 58 Lower clamping roller 60 Heat pressing device (secondary forming device) 61 Upper pressure roller 62 Lower pressure roller CD Orthogonal direction MD machine direction θ Back surface angle

Claims

1. A hook-and-loop fastener (1) having a base portion (10) and a plurality of engaging elements (20) provided on one surface of the base portion (10), each of the engaging elements (20) having a stem portion (22) extending upward from the base portion (10) and an engaging head portion (23) formed integrally with the upper end of the stem portion (22), the base portion (10) and the engaging element (20) contain a thermoplastic resin; The thermoplastic resin is a mixture of 50 parts by weight of plant-derived polyethylene and 50 parts by weight of petroleum-derived polypropylene per 100 parts by weight of the thermoplastic resin, The plant-derived polyethylene has a melt flow rate of 5 g / 10 min or more and 30 g / 10 min or less, and a flexural modulus of 800 MPa or more and 2300 MPa or less, The petroleum-derived polypropylene has a melt flow rate of 5 g / 10 min or more and 60 g / 10 min or less, and a flexural modulus of 600 MPa or more and 2300 MPa or less, The plant-derived polyethylene and the petroleum-derived polypropylene have melt flow rates that are different from each other and flexural moduli that are different from each other, The engaging head (23) has a shape that protrudes outward from the upper end of the stem portion (22) around the entire circumference of the upper end of the stem portion (22), The engaging head (23) has an upwardly facing head top surface (23a), an outer peripheral side surface (23b) that is inclined or curved downward from the outer peripheral edge of the head top surface (23a), and a head back surface (23c) that is disposed between the outer peripheral side surface (23b) and the upper end of the stem portion (22), The back surface angle (θ) between the part of the head back surface (23c) extending from the upper end of the stem portion (22) and an imaginary line (26) extending downward from the upper end of the stem portion (22) is 120° or less. A hook-and-loop fastener characterized by:

2. The engaging element (20) is provided with at least one small claw portion (24) protruding from the outer peripheral edge of the engaging head (23). The hook-and-loop fastener according to claim 1.

3. The minute claws (24) hang downward from the outer peripheral edge of the engaging head (23) toward the base (10). The hook-and-loop fastener according to claim 2.

4. A method for manufacturing a hook-and-loop fastener (1) having a base portion (10) and a plurality of engaging elements (20) provided on one surface of the base portion (10), each of the engaging elements (20) having a stem portion (22) extending upward from the base portion (10) and an engaging head portion (23) formed integrally with an upper end of the stem portion (22), comprising: a primary molding step of melting and supplying a material containing a thermoplastic resin consisting of a mixture of 50 parts by weight of plant-derived polyethylene and 50 parts by weight of petroleum-derived polypropylene per 100 parts by weight of the thermoplastic resin to form a primary molded body (30) having the base portion (10) and a plurality of primary elements (31) provided on one surface of the base portion (10); a secondary forming step of pressing and deforming at least a portion of the primary element (31) to form the engaging element (20) in which the engaging head (23) protrudes outward from the upper end of the stem portion (22) along the entire periphery of the upper end of the stem portion (22); Including, The primary molding step includes: the plant-derived polyethylene has a melt flow rate of 5 g / 10 min or more and 30 g / 10 min or less and a flexural modulus of 800 MPa or more and 2300 MPa or less; The petroleum-derived polypropylene has a melt flow rate of 5 g / 10 min or more and 60 g / 10 min or less and a flexural modulus of 600 MPa or more and 2300 MPa or less; and The plant-derived polyethylene and the petroleum-derived polypropylene have melt flow rates different from each other and bending moduli different from each other. Including, The secondary molding step includes: using a secondary forming device (60) having at least an upper roller (61) equipped with a heating source; bringing the upper roller (61) into contact with the primary element (31) to heat and press the primary element (31) from above; The heating temperature of the upper roller (61) is set to a temperature that is 18°C ​​lower than the weighted average of the melting points of the synthetic resins contained in the thermoplastic resin, or lower; and The engaging head (23) has an upwardly facing head top surface (23a), an outer peripheral side surface (23b) that is inclined or curved downward from the outer peripheral edge of the head top surface (23a), and a head back surface (23c) that is arranged between the outer peripheral side surface (23b) and the upper end of the stem portion (22), and the back surface angle (θ) between the part of the head back surface (23c) that extends from the upper end of the stem portion (22) and an imaginary line (26) that extends downward from the upper end of the stem portion (22) is 120° or less. Contains A method for manufacturing a hook-and-loop fastener, comprising:

5. The heating temperature of the upper roller (61) in the secondary molding step is set to a temperature equal to or higher than a temperature 35°C lower than a weighted average of the melting points of the synthetic resins contained in the thermoplastic resin. A method for producing the hook-and-loop fastener according to claim 4.

6. The primary molding step includes molding the primary molded body (30) using a die wheel (51) that includes an outer cylindrical body (52) having a plurality of through holes (52a) that penetrate from the outer peripheral surface to the inner peripheral surface, and an inner cylindrical body (53) that is disposed in close contact with the inner peripheral surface of the outer cylindrical body (52), and in which a plurality of recesses (53a) are formed on the outer peripheral surface of the inner cylindrical body (53), and in which outer peripheral edges of at least some of the through holes (52a) on the inner peripheral surface of the outer cylindrical body (52) overlap with the recesses (53a) of the inner cylindrical body (53). A method for manufacturing the hook-and-loop fastener according to claim 4 or 5.

7. In the primary molding step, the primary element (31) is molded, the primary element (31) having at least a primary stem portion (32) formed by the through-hole (52a) of the outer cylindrical body (52) and a primary micro-claw portion (34) formed by the recess (53a) of the inner cylindrical body (53); and In the secondary molding step, a micro claw portion (24) protruding from the engaging head portion (23) is formed from the primary micro claw portion (34). A method for producing the hook-and-loop fastener according to claim 6.

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