Patent Application
20240251916
The present invention relates to a surface fastener made of synthetic resin and including a thin-plate-shaped base portion and a plurality of engaging elements provided on the base portion.
A surface fastener product that is used by combining a surface fastener that includes a plurality of engaging elements and another surface fastener with which the engaging elements can be engaged and from which the engaging elements can be disengaged is known. For example, a surface fastener including an engaging element having a shape, such as a mushroom shape or a hook shape, that allows a fiber to be caught is sometimes called a male surface fastener. A member having a function corresponding to the male surface fastener (such as the function of engaging with the engaging element having a mushroom shape or a hook shape) is sometimes called a female-type fastener. In this case, examples of the female surface fastener include a nonwoven fabric and a loop member provided with a plurality of loops for engagement with the engaging element, and a nonwoven fabric formed without providing engaging loops.
For example, International Publication No. 2014/064842 (Patent Literature 1) discloses a surface fastener that is used in, for example, diapers. The surface fastener described in Patent Literature 1 includes a base portion and a plurality of engaging elements that are provided on an upper surface of the base portion, with each engaging element including a stem portion (columnar portion) that protrudes upward from the base portion, and an engaging head portion that is formed on an upper end portion of the stem portion.
In addition, in Patent Literature 1, a group of engaging elements in any range in which the engaging elements are regularly arranged is defined as a set of engaging elements. In this case, when the area of the upper surface of the base portion in the range of the set of engaging elements is S1 and the total area of the upper surfaces of the engaging head portions of the plurality of engaging elements included in the set of engaging elements is S2, the surface fastener in Patent Literature 1 is formed to satisfy the condition of 0.05≤S2/S1≤0.15. Patent Literature 1 describes that the surface fastener that satisfies the condition above is capable of ensuring sufficient engagement force with respect to a female surface fastener such as an unwoven fabric with which the surface fastener is caused to engage.
PTL 1: International Publication No. 2014/064842
As an index that indicates the property of a surface fastener, for example, a peel strength and a shearing strength are known. The peel strength is an engaging strength (joining strength) provided when a male surface fastener and a female surface fastener are pulled so as to be separated relative to each other in a surface-fastener thickness direction (height direction) from a state in which the male surface fastener and the female surface fastener are adhered to and engaged with each other. The shearing strength is an engaging strength provided when a shearing stress is applied to a male surface fastener and a female surface fastener (for example, when the male surface fastener and the female surface fastener are pulled so to be displaced relative to each other in a surface-fastener length direction and/or width direction) from a state in which the male surface fastener and the female surface fastener are adhered to and engaged with each other.
The surface fastener described in Patent Literature 1, by satisfying the condition above, has a proper peel strength that allows it to be used in, for example, diapers. However, a surface-fastener product in which a male surface fastener is attached or a surface-fastener product in which both a male surface fastener and a female surface fastener are attached is required to have a large peel strength to, for example, enhance the performance of the surface-fastener product and cause the surface-fastener product to provide added value.
The present invention has been made in view of the above-described problem of the related art, and an object of the present invention is to provide a surface fastener that includes a base portion and a plurality of engaging elements each including an engaging head portion, and that is capable of providing a large peel strength with respect to a female surface fastener.
To this end, a surface fastener provided by the present invention is a surface fastener made of synthetic resin and including a thin-plate-shaped base portion and a plurality of engaging elements provided on the base portion, each of the engaging elements including a stem portion that protrudes upward from the base portion, and an engaging head portion that is formed on an upper end portion of the stem portion, wherein, in plan view seen from above the engaging elements, when an area of the engaging head portion of one of the engaging elements is defined as a head portion area, the head portion area of each of the engaging elements is 22000 μm2 or greater and 50000 μm2 or less.
In the surface fastener according to the present invention, it is preferable that a plurality of element rows in which the plurality of engaging elements are arrayed along a first direction be provided: when a distance between the engaging head portions of the engaging elements that are adjacent to each other in the first direction is defined as a first head-portion-to-head-portion distance and a distance between the engaging head portions of the element rows that are adjacent to each other in a second direction orthogonal to the first direction is defined as a second head-portion-to-head-portion distance, at least one of the first head-portion-to-head-portion distance and the second head-portion-to-head-portion distance be 200 μm or greater, and the first head-portion-to-head-portion distance and the second head-portion-to-head-portion distance be 430 μm or less; and the head portion area of each of the engaging elements be 41000 μm2 or less.
In this case, it is preferable that an arrangement of the engaging elements include a parallel arrangement in which the engaging elements of each of the element rows are arrayed at a fixed first pitch along the first direction, the plurality of element rows are arrayed at a fixed second pitch along the second direction, and the engaging elements are arrayed along the second direction in two of the element rows that are adjacent to each other in the second direction; in the engaging elements, when a direction that is orthogonal to a height direction of the engaging elements is defined as a horizontal direction, a dimension of each of boundary portions in the horizontal direction be 127 μm or greater, each of the boundary portions being provided between the stem portion corresponding thereto and the engaging head portion corresponding thereto; and the head portion area of each of the engaging elements be 38000 μm2 or less.
It is preferable that the plurality of engaging elements be arrayed at a fixed first pitch along the first direction: the plurality of element rows be arrayed at a fixed second pitch along the second direction: the first pitch and the second pitch be substantially equal to each other; in the engaging elements, when a direction that is orthogonal to a height direction of the engaging elements is defined as a horizontal direction, a dimension of each of boundary portions in the horizontal direction be 127 μm or greater, each of the boundary portions being provided between the stem portion corresponding thereto and the engaging head portion corresponding thereto: the head portion area of each of the engaging elements be 38000 μm2 or less; and a maximum value of a dimension in the second direction of each of the engaging head portions in the plan view be 223 μm or less.
In the present invention, it is preferable that at least one pawl portion be provided in a protruding manner on an outer peripheral edge portion of each of the engaging head portions; and the at least one pawl portion have a pawl width that is smaller than a dimension of a boundary portion in a direction orthogonal to the height direction, the boundary portion being provided between the stem portion corresponding thereto and the engaging head portion corresponding thereto.
In this case, it is preferable that, when the engaging elements are seen in a direction orthogonal to a height direction of the engaging elements, the at least one pawl portion have a pawl upper surface that faces upward and a pawl lower surface that is disposed on a side opposite to the pawl upper surface, and the pawl lower surface have a drooping form in which a tip end portion of the pawl lower surface is disposed lower than a base end portion of the pawl lower surface in the height direction.
The surface fastener of the present invention includes a base portion and a plurality of engaging elements each including an engaging head portion, and is capable of providing a large peel strength with respect to a female surface fastener.
Preferred embodiments of the present invention are described in detail below with reference to the drawings. Note that the present invention is not limited in any way to the embodiments described below, and various changes can be made as long as structures are substantially the same as those of the present invention and similar operational advantages are provided. For example, the length (dimension in a machine direction MD) and the width (dimension in an orthogonal direction CD) of a surface fastener of the present invention are not particularly limited, and the surface fastener may have any shape by, for example, cutting the surface fastener.
In the surface fastener (male surface fastener) of the present invention, due to, for example, improvement in a manufacturing apparatus of the surface fastener, it has become possible to, as described below, form engaging elements having a very small size with a head portion area of each engaging head portion being 41000 μm2 or less, and preferably 38000 μm2 or less when compared with the size of an engaging element of a surface fastener of a related art. It has been considered difficult to form engaging elements including an engaging head portion to have such a small size by a technology of a related art. Further, the surface fastener of the present invention not only includes engaging elements having a small size, but also, as a result of repeated trial manufacture and study, is realized by finding out a proper condition of arranging the engaging elements with respect to the size of the engaging elements.
In the surface fastener of the present invention, when a plurality of engaging elements having a small size such as that described above are arranged so as to satisfy a predetermined condition to thereby engage the surface fastener with a female surface fastener, it is possible to ensure a peel strength that is larger than that in a surface fastener of a related art. Surface fasteners of first and second embodiments of the present invention are described in detail below.
Note that, in the description below, a front-rear direction of the surface fastener and a front-rear direction of a primary molded body are length directions of the primary molded body and the surface fastener molded to be long as described below, or may be said to be a first direction along the machine direction (MD) in which the surface fastener or the primary molded body is transported in a manufacturing process of the surface fastener.
A left-right direction is orthogonal to the length direction and refers to a width direction along an upper surface (or lower surface) of a base portion of the surface fastener. In this case, the left-right direction and the width direction may be said to be an orthogonal direction (CD) or a second direction, which are orthogonal to the machine direction (MD). An up-down direction is orthogonal to the length direction and refers to a thickness direction of the surface fastener and a height direction of an engaging element, which are orthogonal to the upper surface (or the lower surface) of the base portion of the surface fastener.
As described below, by using a manufacturing apparatus 40, shown in
The surface fastener 1 according to the first embodiment is made of a thermoplastic resin, such as polypropylene, polyester, nylon, polybutylene terephthalate, or a copolymer thereof. The surface fastener 1 may be made of biodegradable resin, a plant-derived resin, or a thermoplastic resin obtained by recycling.
The surface fastener 1 includes a flat-plate-shaped base portion 10 that is thin, and a plurality of engaging elements 20 that are provided in a standing manner on an upper surface of the base portion 10 and that are mushroom-shaped. The base portion 10 is formed to be long along the machine direction MD when manufacturing the surface fastener 1. The base portion 10 has a predetermined thickness that allows a proper strength and a proper flexibility to be ensured. The upper surface and the lower surface of the base portion 10 are each flat and are formed parallel to each other.
Each engaging element 20 of the first embodiment includes a stem portion 21 that extends upward from the upper surface of the base portion 10, and an engaging head portion 22 that is formed on an upper end portion of the stem portion 21. Boundary portions 23 are each disposed between the stem portion 21 corresponding thereto and the engaging head portion 22 corresponding thereto.
Each stem portion 21 protrudes in a direction orthogonal to the upper surface of the base portion 10. Each stem portion 21 has a truncated conical shape having a cross section (circular cross section) whose area gradually increases toward the base portion 10, the cross section being orthogonal to the up-down direction. Note that, in the present invention, the shape of each stem portion is not limited to a truncated conical shape, and may be, for example, a truncated pyramidal shape, such as a square truncated pyramidal shape, a circular columnar shape, or a prismatic shape, such as a rectangular prismatic shape.
Each engaging head portion 22 is integrally formed with the stem portion 21 corresponding thereto and is formed on the stem portion 21 with the boundary portion 23 corresponding thereto interposed therebetween. Each engaging head portion 22 has a disk shape or a dish shape so as to protrude outward from the entire periphery of the upper end portion of the stem portion 21. Each engaging head portion 22 is formed to have a relatively small thickness (dimension in the up-down direction), and has a circular shape or an elliptical shape in plan view of the engaging element 20 corresponding thereto (see
For example, when a direction, such as the front-rear direction or the left-right direction, that is orthogonal to the height direction is defined as a horizontal direction and when each engaging element 20 is seen from the horizontal direction (see
The head-portion top end surface 22a of each engaging head portion 22 is disposed parallel to the upper surface of the base portion 10. Each outer peripheral side surface 22c, which is a curved surface, is provided over the entire engaging head portion 22 in a peripheral direction between the head-portion top end surface 22a and the head-portion rear surface 22b. In the first embodiment, each outer peripheral side surface 22c is curved so as to be inclined downward from the outer-peripheral edge portion of the head-portion top end surface 22a to the outer-peripheral edge portion of the head-portion rear surface 22b.
The head-portion rear surface 22b of each engaging head portion 22 is disposed so as to face the base portion 10 on a side opposite to the head-portion top end surface 22a in the up-down direction. Each head-portion rear surface 22b has a doughnut shape or a ring shape that surrounds the stem portion 21.
Here, for example, as shown in
In the first embodiment, each head-portion rear surface 22b is formed such that its head-portion rear-surface angle θ is 120 degrees or less, and is preferably 90 degrees or less. Therefore, when a loop or a fiber of a female surface fastener (for example, a loop member and unwoven fabric) is caught by and engages with a rear side of each engaging head portion 22, it is possible to stably hold the engaged loop or fiber and make it less likely for the loop or the fiber to be disengaged from each engaging element 20. In the first embodiment, although a lower limit of the head-portion rear-surface angle θ is not particularly limited, it is preferable that the rear-surface angle be 45 degrees or greater and particularly be 70 degrees or greater when taking into consideration, for example, the facility with which the loop or the fiber of the female surface fastener moves into the rear side of each engaging head portion 22.
Note that, in the first embodiment and the second embodiment to be described below, when each engaging element 20 is seen from the horizontal direction, its head-portion rear surface 22b is a flat surface or a substantially flat surface. However, in the present invention, the head-portion rear surface 22b may be entirely or partly curved between the outer peripheral side surface 22c and the boundary portion 23 with the stem portion 21. In this case, the head-portion rear-surface angle θ above is defined by an angle that is formed by a straight line with respect to the height direction of an engaging element, the straight line being formed when the straight line connects in a virtual manner the boundary portion and a position of a boundary between the head-portion rear surface and the outer peripheral side surface of an engaging head portion.
As described above, when a head-portion rear surface 22b is entirely or partly curved, the head-portion rear-surface angle θ formed by the head-portion rear surface 22b with respect to the height direction of the engaging element 20 changes at the entire or a part of the head-portion rear surface 22b in accordance with the position of the head-portion rear surface 22b (for example, the distance from the boundary portion 23). In this case, at a portion where the inclination angle of the head-portion rear surface 22b is the smallest (in other words, a portion extending on a most downward side), it is preferable that a part of the head-portion rear-surface angle θ with respect to the height direction be 60 degrees or less, and particularly be 5 degrees to 45 degrees. Therefore, when the loop or the fiber of the female surface fastener is caught by and engages with the engaging head portion 22, it is possible to make it less likely for the loop or the fiber to be disengaged from the engaging element 20.
Further, each engaging head portion 22 having a disk shape is such that a cross section of each engaging head portion 22 along a radial direction has a fixed shape or a substantially fixed shape in its entirety in a peripheral direction. Note that, in the present invention, each engaging head portion 22 may be formed such that the cross section of each engaging head portion 22 along the radial direction entirely or partly changes in the peripheral direction.
In plan view seen from above the surface fastener 1, when the area of the engaging head portion 22 of one engaging element 20 is defined as a head portion area S, each engaging element 20 is formed such that its head portion area S is 22000 μm2 to 50000 μm2, is preferably 22000 μm2 to 41000 μm2, and is more preferably 22000 μm2 to 38000 μm2.
When the surface fastener 1 is molded as a result of the head portion area S of each engaging element 20 being 22000 μm2 or greater, it is possible to easily fill a die member (described later) with molten resin and thus it is possible to stably form each engaging element 20 to have a predetermined shape. Each engaging element 20 is formed to have a small size with its head portion area S being 50000 μm2 or less, being preferably 41000 μm2 or less, and being more preferably 38000 μm2 or less. Therefore, when the surface fastener 1 is to be engaged with a female surface fastener, it is possible to deeply and easily insert each engaging element 20 into a loop or a fiber of the female surface fastener, as a result of which it is possible to effectively increase the peel strength and further the shearing strength with respect to the female surface fastener. For example, when the head portion area S of each engaging element 20 is within the aforementioned range, the surface fastener 1 can have a peel strength of 0.50 N/cm or greater, and further a peel strength of 0.57 N/cm or greater. Note that the head portion area S of each engaging element 20 can be determined from, for example, image data of images photographed from above the surface fastener 1. When each engaging element 20 has a circular shape or an elliptical shape in plan view, the head portion area S of each engaging element 20 can be calculated from the diameter of the engaging head portion 22 corresponding thereto.
In each engaging element 20, for example, as shown in
When the dimension in the horizontal direction of each boundary portion 23 is 125 μm or greater and is preferably 127 μm or greater, and when the surface fastener 1 is molded, it is possible to easily fill a cavity of the die member with molten resin and to stably mold each engaging element 20 having a predetermined shape. As a result, the manufactured surface fastener 1 can stably have excellent peel strength. On the other hand, when the dimension in the horizontal direction of each boundary portion 23 is less than 174 μm and is preferably 158 μm or less, each engaging element 20 can be formed to have a small size.
In each engaging element 20, a maximum value of a dimension in the left-right direction (the orthogonal direction CD) of each engaging head portion 22 in plan view of the surface fastener 1 is 246 μm or less and is preferably 223 μm or less. The height from the upper surface of the base portion 10 to the head-portion top end surface 22a of the engaging head portion 22 of each engaging element 20 (the dimension in the up-down direction) is 230 μm or greater and 290 μm or less, and is preferably 238 μm or greater and 83 μm or less.
In the first embodiment, as shown in
Further, in the case of the first embodiment, the first pitch P1 and the second pitch P2 are substantially equal to each other. Here, “substantially equal to each other” not only means that the first pitch P1 and the second pitch P2 are equal to each other but also includes a case in which there is an error of ±10%.
As shown in
When a plurality of small engaging elements 20 are to be arranged in parallel, as a result of setting at least one of the first head-portion-to-head-portion distance D1 and the second head-portion-to-head-portion distance D2 to be 200 μm or greater, it is possible to easily insert a loop or a fiber of a female surface fastener into a location between the engaging elements 20 and thus it is possible to easily engage the loop or the fiber with the engaging elements 20.
When both of the first head-portion-to-head-portion distance D1 and the second head-portion-to-head-portion distance D2 are set to be 430 μm or less, it is possible to suppress the loop or the fiber of the female surface fastener from excessively moving into a location between the engaging elements 20 and to efficiently engage the loop or the fiber of the female surface fastener with the engaging elements 20. In addition, a reduction in strength caused by a decrease in the number of engaging elements 20 that are set in the entire surface fastener 1 is prevented. Therefore, as a result of setting the first head-portion-to-head-portion distance D1 and the second head-portion-to-head-portion distance D2 within the aforementioned ranges, when the surface fastener 1 is engaged with the female surface fastener, it is possible to easily obtain a large peel strength and to increase the shearing strength.
Note that, in the first embodiment, as an arrangement pattern of the plurality of engaging elements 20, instead of the above-described parallel arrangement, a staggered arrangement may be used (see, for example,
Next, a method of manufacturing the surface fastener 1 according to the above-described first embodiment is described.
The surface fastener 1 according to the first embodiment is manufactured by using the manufacturing apparatus 40 shown in
The molding device 41 includes a die wheel 42 that rotates in one direction (in the drawing, a counterclockwise direction), a nozzle portion 45 that is disposed to face a peripheral surface of the die wheel 42, and a pickup roller 46 that is disposed downstream with respect to the nozzle portion 45 in a rotation direction of the die wheel 42.
The die wheel 42 includes a circular cylindrical body (sleeve) 43, which is a die member, and a rotational driving roller 44 that rotates the circular cylindrical body 43 in one direction. A cooling jacket (not shown) that allows a cooling liquid to circulate is provided inside the rotational driving roller 44. The cooling jacket allows efficient cooling of the primary molded body 5 (described below) that is molded at an outer peripheral surface portion of the die wheel 42.
As shown in
The plurality of through holes 43a are formed in correspondence with the positions of the engaging elements 20 of the surface fastener 1 to be manufactured. The plurality of through holes 43a are formed in a fixed formation pitch along a peripheral direction of the circular cylindrical body 43 (the machine direction MD), and are formed at a fixed formation pitch along an axial direction (the orthogonal direction CD) parallel to a central axis of the circular cylindrical body 43.
In particular, in the first embodiment, the formation pitch of the through holes 43a along the machine direction MD and the formation pitch of the through holes 43a along the orthogonal direction are each set to be 200 μm or less and 600 μm or less, and are each preferably set to be 400 μm or less and 600 μm or less. In the case of the first embodiment, the formation pitch of the through holes 43a along the machine direction MD and the formation pitch of the through holes 43a along the orthogonal direction CD are substantially equal to each other.
Note that, in the present invention, the formation pitch of the through holes 43a along the machine direction MD and the formation pitch of the through holes 43a along the orthogonal direction CD may differ from each other. When the formation pitch of the through holes 43a along the machine direction MD and the formation pitch of the through holes 43a along the orthogonal direction CD differ from each other, it is preferable that the formation pitch along the orthogonal direction CD be larger than the formation pitch along the machine direction MD.
The nozzle portion 45 is disposed to be separated from the outer peripheral surface of the die wheel 42. Molten synthetic resin is continuously supplied toward the die wheel 42 from the nozzle portion 45.
The pickup roller 46 includes an upper nipping roller 46a and a lower nipping roller 46b, which constitute a pair of nipping rollers, that nip and pull the primary molded body 5, molded at the outer peripheral surface portion of the die wheel 42, from above and below the primary molded body 5. The upper nipping roller 46a and the lower nipping roller 46b are disposed apart from each other with a predetermined interval therebetween and opposite to each other.
An outer peripheral surface portion of the upper nipping roller 46a and an outer peripheral surface portion of the lower nipping roller 46b are each provided with a surface layer (not shown) made of elastomer, such as polyurethane elastomer. When the upper nipping roller 46a and the lower nipping roller 46b, which constitute a pair of nipping rollers, each rotate in correspondence with a predetermined speed in a predetermined direction, it is possible to smoothly send out the primary molded body 5 toward a downstream side while continuously separating the primary molded body 5 from the die wheel 42.
The heating pressing device 51 includes an upper pressing roller (upper calender roller) 52 and a lower pressing roller (lower calender roller) 53, which are a pair of rollers, that are disposed on a downstream side of the pickup roller 46. The upper pressing roller 52 and the lower pressing roller 53 are disposed apart from each other with a predetermined interval therebetween and opposite to each other. It is possible to adjust the interval between the upper pressing roller 52 and the lower pressing roller 53 by height adjusting means (not shown).
The upper pressing roller 52 is disposed so as to rotate in a counterclockwise direction in
The primary molded body 5 molded by the molding device 41 is introduced between the upper pressing roller 52 and the lower pressing roller 53. Therefore, the upper pressing roller 52 and the lower pressing roller 53 press the temporary element 60 of the primary molded body 5 from above and below the temporary element 60 to decrease the height (dimension in the up-down direction) of the temporary element 60 and to deform an upper end portion of the temporary element 60.
When the manufacturing apparatus 40 including the molding device 41 and the heating pressing device 51, which are described above, is used to manufacture the surface fastener 1, first, the primary molding step of molding the primary molded body 5 by the molding device 41 is performed. In the primary molding step, molten synthetic resin is continuously supplied toward the outer peripheral surface portion of the rotating die wheel 42 from the nozzle portion 45.
At this time, since the die wheel 42 is drivingly rotated in one direction, when synthetic resin is supplied to the peripheral surface of the die wheel 42, the primary molded body 5 in which a plurality of temporary elements 60, like that shown in
The primary molded body 5 is hardened by rotating through an angle of 180 degrees while being carried and cooled on the outer peripheral surface portion of the die wheel 42. Then, the hardened primary molded body 5 is continuously separated from the outer peripheral surface of the die wheel 42 by the pickup roller 46.
Next, the primary molded body 5 that has been separated from the die wheel 42 is transported toward the heating pressing device 51 that performs a secondary molding step, and is introduced between the upper pressing roller 52 and the lower pressing roller 53 of the heating pressing device 51. In the secondary molding step, the upper pressing roller 52 heats at least an upper end portion of each temporary element 60 of the primary molded body 5, and the upper pressing roller 52 and the lower pressing roller 53 press the temporary elements 60 in the up-down direction. Therefore, the heights of the temporary elements 60 are decreased and are made equal to each other to fixed heights, and the upper end portion of each temporary element 60 is deformed into a disk shape in which a top end surface thereof is flat.
As a result, the surface fastener 1 of the first embodiment shown in
In the surface fastener 1 of the first embodiment manufactured by a method such as that described above, each engaging element 20 is formed to have a very small size, the formation of such very small engaging elements being considered as hitherto being difficult to manufacture. Specifically, each engaging element 20 is formed to have a size such that, in plan view of the surface fastener 1 (see
Such a surface fastener (male surface fastener) 1 of the first embodiment can be repeatedly engaged with and disengaged from a female surface fastener. In this case, as the female surface fastener, for example, a loop member that is formed by intertwining a plurality of loops and fibers, or a loopless unwoven fabric not including loops is used. It is preferable that the loop member be formed with a basis weight of approximately 20 g/m2 to 50 g/m2. It is preferable that the loopless unwoven fabric be formed with a basis weight of, for example, approximately 10 g/m2 to 20 g/m2, and the loopless unwoven fabric is sometimes called a back sheet.
In the surface fastener 1 having the head portion area S, the first head-portion-to-head-portion distance D1, and the second head-portion-to-head-portion distance D2 above, when the surface fastener 1 is engaged with a female surface fastener, the small engaging elements 20 of the surface fastener 1 can deeply and easily move into locations between a plurality of loops or between a plurality of fibers. In addition, it is possible to easily properly accommodate the plurality of loops or the plurality of fibers in a space between the engaging elements 20. As a result, it is possible to effectively increase the peel strength of the surface fastener (male surface fastener) 1 with respect to the female surface fastener.
In addition, in the first embodiment, as shown in
When the plurality of engaging elements 20 are formed to have such sizes and to be disposed in such an arrangement, the surface fastener 1 can have a proper shearing strength with respect to a female surface fastener. That is, when the surface fastener 1 is used in, for example, diapers, the surface fastener 1 can stably have a proper shearing strength that can withstand such use. In addition, at the same time, it is possible to suppress the shearing strength from becoming too large. Therefore, for example, when, with the surface fastener 1 engaged with the female surface fastener, the surface fastener 1 is subjected to a large shearing stress, it is possible to easily disengage the surface fastener 1 from the female surface fastener. Therefore, it is possible to make less likely occurrence of a problem such as the engaging elements damaging (cutting) the loops or the fibers of the female surface fastener as a result of the engagement state being maintained when the surface fastener 1 is subjected to a shearing stress.
Further, in the first embodiment, with regard to the plurality of engaging elements 20 that are disposed in a parallel arrangement, the first pitch P1 in the front-rear direction and the second pitch P2 in the left-right direction are substantially equal to each other. In this case, it is preferable that the head portion area S of each engaging element 20 in plan view be 38000 μm2 or less, the dimension in the horizontal direction of the boundary portion 23 of each engaging element 20 be 127 μm or greater, and the maximum value of a dimension in the left-right direction (the orthogonal direction CD) of the engaging head portion 22 of each engaging element 20 in plan view of the surface fastener 1 be 223 μm or less.
When the plurality of engaging elements 20 are formed to have such sizes and to be disposed in such an arrangement, each engaging element 20 can be stably formed as a small (thin) engaging element, and the strength of each engaging element 20 can be properly increased. Therefore, it is possible to further increase the peel strength of the surface fastener 1.
A surface fastener 2 according to the second embodiment includes a plurality of very small pawl portions 74 on the engaging head portion 72 of each engaging element 70. With regard to the surface fastener 2 according to the second embodiment, portions that differ from those of the first embodiment and characteristic portions thereof are primarily described below.
The surface fastener 2 of the second embodiment includes a base portion 10 and a plurality of engaging elements 70 that are provided in a standing manner on an upper surface of the base portion 10. The base portion 10 is substantially the same as the base portion 10 of the first embodiment.
Each engaging element 70 of the second embodiment includes a truncated conical stem portion 71 that protrudes from the upper surface of the base portion 10, an engaging head portion 72 that is integrally formed with an upper end portion of the stem portion 71, and two very small pawl portions 74 that protrude from an outer peripheral edge portion of the engaging head portion 72. Boundary portions 73 are each disposed between the stem portion 71 corresponding thereto and the engaging head portion 72 corresponding thereto.
Each engaging head portion 72 has a disk shape or a dish shape so as to protrude outward from the entire periphery of the upper end portion of the stem portion 71 corresponding thereto. Each engaging head portion 72 has a circular shape or an elliptical shape in plan view of the engaging element 70 corresponding thereto (see
When each engaging element 70 is seen from the horizontal direction orthogonal to the height direction (see
The head-portion rear surface 72b of each engaging head portion 72 is disposed so as to face the base portion 10 on a side opposite to the head-portion top end surface 72a in the up-down direction. When each engaging element 70 is seen from the horizontal direction, each head-portion rear surface 72b is formed such that its head-portion rear-surface angle θ is 120 degrees or less.
Each engaging head portion 72 having a disk shape is such that a cross section of each engaging head portion 72 along a radial direction has a fixed shape or a substantially fixed shape in its entirety in a peripheral direction. Note that, in the present invention, each engaging head portion 72 may be formed such that the cross section of each engaging head portion 72 along the radial direction entirely or partly changes in the peripheral direction.
Each engaging element 70 includes two very small pawl portions 74 that protrude outward from the outer peripheral side surface 72c of the engaging head portion 72 corresponding thereto. The two pawl portions 74 of each engaging element 70 are regularly arranged with respect to one engaging head portion 72. Specifically, along a radial direction of the engaging head portion 72 having a circular shape in plan view, the two pawl portions 74 each protrude in a direction of radial extension from the outer peripheral side surface 72c of the engaging head portion 72 with reference to the center of the engaging head portion 72. In particular, in the case of the second embodiment, the two pawl portions 74 protrude in opposite directions along the left-right direction (second direction) from the engaging head portion 72 such that they are in a point-symmetrical positional relationship with respect to each other in plan view of the engaging element 70.
Note that, in the present invention, the shape and the number of pawl portions of each engaging element are not particularly limited. In the present invention, for example, the engaging head portion 72 of each engaging element 70 may include only one pawl portion, may include four pawl portions 74 that are regularly provided as shown in
In the second embodiment, each pawl portion 74 has a shape, like a claw of a bird, extending downward toward its tip. When each engaging element 70 is seen in the horizontal direction, each pawl portion 74 has a pawl upper surface that faces upward and a pawl lower surface that is disposed on a side opposite to the pawl upper surface. The pawl lower surface has a drooping form in which a tip end portion of the pawl lower surface is disposed lower than a base end portion of the pawl lower surface in the height direction. In this case, the pawl lower surface of each pawl portion 74 is formed to have a shape that inclines downward toward the pawl tip end portion with respect to the head-portion rear surface 72b of the engaging head portion 72 corresponding thereto. That is, the inclination angle of the pawl lower surface of each pawl portion 74 and the inclination angle of the head-portion rear surface 72b of each engaging head portion 72 differ from each other (the inclination angles being, for example, angles of inclination with respect to a horizontal plane parallel to the upper surface of a base plate portion).
Further, each pawl portion 74 has a pair of side wall surfaces that are disposed in the pawl upper surface and the pawl lower surface. Here, a dimension between the pair of side wall surfaces at the base end portion of each pawl portion 74 (end portion where each pawl portion 74 is joined to the engaging head portion 72) is defined as a pawl width. In this case, each pawl portion 74 has a pawl width that is smaller than a dimension in the horizontal direction of the boundary portion 73 of the engaging element 70 corresponding thereto. In particular, in the case of the second embodiment, the pawl width of each pawl portion 74 is ⅓ or less, is preferably ⅕ or less, and is more preferably 1/7 or less of the dimension in the horizontal direction of the boundary portion 73 above. When each pawl portion 74 has such a pawl width, it is possible to keep small the influence of the pawl portions 74 of each engaging element 70 on the comfortableness of the surface fastener 2 to the touch.
In the second embodiment, as in the case of the first embodiment, each engaging element 70 is formed such that its head portion area S is 22000 μm2 or greater and 41000 μm2 or less, and is preferably 22000 μm2 or greater and 38000 μm2 or less. Therefore, it is possible to form each engaging element 70 to have a predetermined shape, effectively increase the peel strength with respect to a female surface fastener, and further increase the shearing strength.
The dimension in the horizontal direction of the boundary portion 73 of each engaging element 70 is 125 μm or greater and less than 174 μm, and is preferably 127 μm or greater and 158 μm or less. A maximum value of a dimension in the left-right direction (the orthogonal direction CD) of each engaging head portion 72 in plan view of the surface fastener 2 is 246 μm or less and is preferably 223 μm or less. The height from the upper surface of the base portion 10 to the head-portion top end surface 72a of the engaging head portion 72 of each engaging element 70 is 230 μm or greater and 290 μm or less, and is preferably 238 μm or greater and 283 μm or less.
As shown in
In addition, in the second embodiment, as shown in
Note that, in the second embodiment, as an arrangement pattern of the plurality of engaging elements 70, instead of the above-described parallel arrangement, a staggered arrangement may be used as shown in
The surface fastener 2 according to the second embodiment shown in
A molding device 41a of the manufacturing apparatus 40a includes a die wheel 47. The die wheel 47 includes a circular cylindrical outer circular cylindrical body (outer sleeve) 48, a circular cylindrical inner circular cylindrical body (inner sleeve) 49 that is disposed in close contact with an inner side of the outer circular cylindrical body 48, and a rotational driving roller 44 that rotates the outer circular cylindrical body 48 and the inner circular cylindrical body 49 in one direction. In this case, the die wheel 47 has a double circular cylinder structure in which the outer circular cylindrical body 48 and the inner circular cylindrical body 49 are rotatably and concentrically disposed.
A plurality of through holes 48a that extend from an outer peripheral surface to an inner peripheral surface of the outer circular cylindrical body 48 of the die wheel 47 are formed in the outer circular cylindrical body 48 as cavities for molding a primary stem portion 81 (described below) of a primary molded body 6. A plurality of recessed grooved portions 49a are formed in an outer peripheral surface of the inner circular cylindrical body 49. Each recessed grooved portion 49a is recessed in a straight line along the orthogonal direction CD parallel to a central axis of the inner circular cylindrical body 49. Each recessed grooved portion 49a has a size that allows molten synthetic resin to flow into each recessed grooved portion 49a. In particular, in the case of the second embodiment, the recessed grooved portions 49a of the inner circular cylindrical body 49 are formed in a peripheral direction (the machine direction MD) at a predetermined pitch so as to overlap the diameters of the through holes 48a formed in the outer circular cylindrical body 48. The recessed grooved portions 49a of the inner circular cylindrical body 49 intersect a circular outer peripheral edge formed on an inner-peripheral-surface side of each through hole 48a of the outer circular cylindrical body 48.
When the manufacturing apparatus 40a of the second embodiment is used to manufacture the surface fastener 2, first, a primary molding step of molding the primary molded body 6 by the molding device 41a is performed. In the primary molding step, molten synthetic resin is continuously supplied toward the rotating die wheel 47 from a nozzle portion 45.
Therefore, the primary molded body 6 in which a plurality of temporary elements 80, like that shown in
In this case, in the first molding step, rib portions 82 and sets of two protruding portions 83 are molded by causing molten synthetic resin to flow into the recessed grooved portions 49a of the inner circular cylindrical body 49 from the through holes 48a of the outer circular cylindrical body 48. Each rib portion 82 is formed along the orthogonal direction CD on the upper surface of the primary stem portion 81 corresponding thereto.
The sets of two protruding portions 83 are not molded by filling the entire recessed grooved portions 49a of the inner circular cylindrical body 49 with synthetic resin, but are molded when synthetic resin that has flowed into the recessed grooved portions 49a from the through holes 48a of the outer circular cylindrical body 48 enters an outer side of a formation range of the through holes 48a along the recessed grooved portions 49a. The protruding portions 83 that are molded in the primary molding step are portions that, by pressing the temporary elements 80 from above the temporary elements 80 in a secondary molding step, become very small pawl portions 74 of the engaging elements 70.
The primary molded body 6 of the second embodiment is hardened by rotating through an angle of 180 degrees while being carried and cooled on an outer peripheral surface portion of the die wheel 47. Then, the hardened primary molded body 6 is continuously separated from an outer peripheral surface of the die wheel 47 by a pickup roller 46.
Next, the primary molded body 6 that has been separated from the die wheel 47 is transported toward a heating pressing device 51 that performs the secondary molding step, and is introduced between an upper pressing roller 52 and a lower pressing roller 53 of the heating pressing device 51. At this time, the upper pressing roller 52 heats at least an upper end portion of each temporary element 80 of the primary molded body 6, and the upper pressing roller 52 and the lower pressing roller 53 press the temporary elements 80 in the up-down direction.
Therefore, the upper end portion of the primary stem portion 81, the rib portion 82, and the protruding portions 83 of each temporary element 80 are thermally deformed to mold each engaging head portion 72 having a flat head-portion top end surface 72a, and to mold two very small pawl portions 74 from the protruding portions 83, the very small pawl portions 74 protruding from an outer peripheral side surface 72c of the engaging head portion 72 corresponding thereto. As a result, the surface fastener 2 of the second embodiment shown in
In the surface fastener 2 of the second embodiment manufactured by the above-described method, as in the first embodiment, each engaging element 70 is formed to have a very small size with the head portion area S of its engaging head portion 72 being 22000 μm2 or greater and 41000 μm2 or less. Therefore, the surface fastener 2 of the second embodiment can also provide advantageous effects similar to those of the surface fastener 1 of the first embodiment. Note that the method of forming the pawl portions 74 is not limited to the above-described method.
The present invention is described in more detail below with reference to examples and reference examples.
As surface fasteners of Examples 1 to 12 and Reference Examples 1 to 6, surface fasteners in which each engaging element had the shape described in the second embodiment (see
Then, with regard to the surface fasteners obtained in Examples 1 to 12 and Reference Examples 1 to 9, the first head-portion-to-head-portion distance D1, the second head-portion-to-head-portion distance D2, the head portion area S, the arrangement of the engaging elements, the first pitch P1 in the first direction, the second pitch P2 in the second direction, the dimension in the horizontal direction (specifically, the second direction) of the boundary portion of each engaging element, and the maximum value of the dimension of each engaging head portion in the second direction were measured. The results of measurements are given in Table 1 below.
Note that the first and second head-portion-to-head-portion distances D1 and D2 were determined by measuring an interval between outer peripheries of head portions by using a digital microscope VHX-6000. From the first and second pitches P1 and P2 and first and second head-portion-to-head-portion distances D1 and D2 of the engaging elements defined by the die wheel 42, the diameter of each engaging head portion in the first direction and the diameter of each engaging head portion in the second direction were calculated. The head portion area S was calculated from the diameter of each engaging head portion in the first direction and the diameter of each engaging head portion in the second direction. The dimension of each boundary portion between a stem portion and the engaging head portion corresponding thereto was determined by measuring the dimension in the second direction of each boundary portion when seen from the first direction orthogonal to the height direction of each engaging element by using a digital microscope VHX-6000.
As shown in Table 1, although the first pitch P1 and the second pitch P2 of the engaging elements differed from each other for the surface fastener of Example 11 and the surface fastener of Reference Example 5, the first pitch P1 and the second pitch P2 were the same for the other surface fasteners. Further, with regard to the surface fasteners of Examples 1 to 12 and Reference Examples 1 to 9, the results of measurement or calculation of the height of each engaging element from an upper surface of a base portion, the thickness of each engaging head portion (dimension in the up-down direction from an upper surface of each engaging head portion to the boundary portion corresponding thereto), the thickness of the base portion, and the formation density of the engaging elements are given as references in Table 2 below.
Next, tests for measuring peel strength and shearing strength were performed on the surface fasteners of Examples 1 to 12 and Reference Examples 1 to 9.
In the test for measuring the peel strength, the surface fasteners of Examples 1 to 12 and Reference Examples 1 to 9 were cut to a size of a 25 mm×25 mm square, and a cut piece 93 of each cut surface fastener was adhered to a supporting member, made of an unwoven fabric, to thereby prepare a first test piece 91 on a surface fastener (male surface fastener) side (see
Next, as shown in
In the test for measuring the shearing strength, the surface fasteners of Examples 1 to 12 and Reference Examples 1 to 9 were cut to a size of a 25 mm×13 mm rectangle, and a cut piece 96 of each cut surface fastener was adhered to a supporting member, made of an unwoven fabric, to thereby prepare a first test piece 94 on a surface fastener (male surface fastener) side (see
The above-described tests for measuring the peel strength and the shearing strength were performed on a plurality of surface fasteners for each fastener of a corresponding of Examples 1 to 12 and Reference Examples 1 to 9, and the average value of the measured peel strengths and the average value of the measured shearing strengths were each calculated. Note that, with regard to Reference Example 9, a test for measuring shearing strength was not performed. The average value of the peel strengths and the average value of the shearing strengths calculated for each surface fastener are shown in Table 1 below.
As shown in Table 1, with regard to the surface fasteners of Examples 1 to 12 that satisfy three conditions, that is, (1) in plan view of the surface fastener, the head portion area S of each engaging element is 22000 μm2 or greater and 41000 μm2 or less, (2) at least one of the first head-portion-to-head portion distance D1 and the second head-portion-to-head portion distance D2 is 200 μm or greater, and (3) both of the first head-portion-to-head portion distance D1 and the second head-portion-to-head portion distance D2 are 430 μm or less, it was confirmed that each surface fastener had a high peel strength of 0.57 N/cm or greater.
On the other hand, the measured peel strengths of the surface fasteners of Reference Examples 1 to 9 that do not satisfy at least one of the aforementioned three conditions each had a numerical value smaller than those of the surface fasteners of Examples 1 to 12. In addition, in the surface fasteners of Reference Examples 1, 2, and 4, the head portion area S was very small, and pawl portions of the engaging elements could not be distinctly confirmed at outer peripheral edge portions of the engaging head portions.
With regard to, of the surface fasteners of Examples 1 to 12, the surface fasteners of Examples 2 to 7 that satisfy, in addition to conditions (1) to (3) above, three additional conditions, that is, (4) the plurality of engaging elements are disposed in a parallel arrangement, (5) in plan view of the surface fastener, the head portion area S of each engaging element is 38000 μm2 or less, and (6) the dimension in the horizontal direction of the boundary portion of each engaging element is 127 μm or greater, it was confirmed that each surface fastener had a shearing strength of 9.52 N/cm2 or less, which was a proper value that was not too large.
As long as a surface fastener is the same as any one of the surface fasteners of Examples 2 to 7, for example, even if the surface fastener is subjected to a large shearing stress when engaged with a female surface fastener, the surface fastener and the female surface fastener can be easily disengaged from each other, as a result of which it is possible to make it less likely for a problem such as loops or fibers of the female surface fastener being damaged (cut) to occur.
With regard to, of the surface fasteners of Examples 1 to 12, the surface fasteners of Examples 3 to 5, Example 7, and Example 10 that satisfy, in addition to conditions (1) to (3) above, four additional conditions, that is, (7) the first pitch P1 and the second pitch P2 are substantially equal to each other, (8) in plan view of the surface fastener, the head portion area S of each engaging element is 38000 μm2 or less, (9) the dimension in the horizontal direction of the boundary portion of each engaging element is 127 μm or greater, and (10) a maximum value of a dimension in the orthogonal direction CD (the second direction) of the engaging head portion of each engaging element in plan view of the surface fastener is 223 μm or less, it was confirmed that the peel strength was 0.70 N/cm or greater, which was an even larger value.
Note that it was confirmed that, in plan view of each surface fastener, when the head portion area S of each engaging element is 22000 μm2 or greater and 50000 μm2 or less, the peel strength was 0.50 N/cm or greater.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP21/22368 | 6/11/2021 | WO |
