Patent Description:
Patent Documents <NUM> and <NUM> disclose a mesh-type (or net-type) touch fastener including: a first set of a plurality of plastically deformed thermoplastic strands; and a second set of a plurality of strands formed integrally with the first set of strands and not present on the same plane as the first set of strands, wherein hooks are provided on at least one of the first set of strands and the second set of strands. This touch fastener is made of a synthetic resin yet is excellent in breathability.

Patent Documents <NUM> and <NUM> essentially disclose mesh-type touch fasteners in accordance with the preamble of claim <NUM>.

<CIT> is directed at a hook mechanical fastener/fibrous composite comprising hook elements on hook containing backing elements or a netting embedded in a fibrous web. The hook elements preferably are on backing elements that are connected or integral and can be strands oriented at angles to each other in a net form. The backing elements generally have a first outer face and a second outer face. The backing elements on at least one of the first or second outer faces have a plurality of hook elements. The hook containing backing elements are embedded within a fibrous web, preferably by hydroentangling the fibers around the backing element, preferably without use of auxiliary attachment means such as adhesives or point bonding.

<CIT> concerns a reticulated web, mesh or netting, the polymeric netting comprising two sets of strands at angles to each other and formed from a profile extruded three dimensional film having a first face and a second face. The profile extruded film is cut in regular intervals along the X-dimension on one or more faces or alternatively in alternating fashion on the first face and the second face. The cut film is then stretched (oriented) in the lengthwise dimension creating a nonplanar netting characterized by land portions on the top and bottom surfaces with connecting leg portions extending between the land portion on the top and bottom surfaces.

<CIT> discloses a fastener, comprising: a uniaxially oriented polymeric substrate; a plurality of hooks disposed on a first side of said substrate; and a plurality of loops disposed on a second side of said substrate; wherein said fastener has a longitudinal axis, and wherein said substrate is oriented along said longitudinal axis.

In <CIT>, a molded surface fastener is manufactured by extruding molten thermoplastic resin, in a predetermined width, from an extrusion nozzle to a circumferential surface of a die wheel having a multiplicity of engaging-element-forming cavities, driving the die wheel for rotation, and molding a multiplicity of engaging elements integrally with a plate-like substrate sheet. At the same time, pseudo elements are molded integrally with the substrate sheet along opposite side edges, using pseudo-element-forming cavities in opposite side circumferential surfaces of the die wheel simultaneously. With the pseudo elements, the molded surface fastener is peeled off the die wheel under a uniform peeling force through the entire width of the substrate sheet.

The mesh-type touch fasteners disclosed in Patent Documents <NUM> and <NUM> are formed using a thermoplastic resin such as a polyolefin-based resin, polyvinyl chloride, polystyrene, nylon, or polyethylene terephthalate. However, because these resins are inelastic polymer materials, the manufactured touch fasteners are poor in elasticity or stretchability. Therefore, in a case where they are used in applications where relative movement of portions to be engaged occurs in various directions, for example, in cases where they are used for fixing members in a moving body such as an automobile (for example, fixing a cushioning member and an outer layer member of a seat), joining tongue pieces on the right and left sides of a foot insertion portion in a shoe instep, and wrapping a supporter around an arm or leg, in particular, in a case where a large impact load is applied, the touch fasteners disclosed in Patent Documents <NUM> and <NUM> do not have sufficient followability and may be easily damaged, resulting in easy disengagement between the engagement elements and a mating member (if the engagement elements are hooks, the mating member is a loop member). Patent Documents <NUM> and <NUM> also describe that one of a base layer forming the strands, ribs, and the engagement elements is made as an elastic layer by coextrusion or the like. However, all of the forms disclosed specifically as examples are combinations with an inelastic layer, and thus cannot fully exhibit an elastic function, and there is room for improvement in followability to the relative movement of the portions to be engaged.

The present invention was made in consideration of the above, and has an object to provide a touch fastener that not only is excellent in breathability but also has high followability to the relative movement of portions to be engaged and does not easily separate from a mating member, and thus is usable in a wider range of applications, and to provide a method of manufacturing the same.

Adoptable is a configuration in which the second strands each include: a stem extending along a direction intersecting with the longitudinal direction of the first strands; and a cap portion projecting to both sides of the stem at an end portion of the stem, and
a thickness of the cap portions is smaller than a thickness of the first strands.

In this case, preferably, the thickness of the cap portions is in a range of <NUM>/<NUM> to <NUM>/<NUM> of the thickness of the first strands.

Adoptable is a configuration in which the second strands each include: a stem extending along a direction intersecting with the longitudinal direction of the first strands; and a cap portion projecting to both sides of the stem at an end portion of the stem, and
a thickness of the cap portions is equal to or more than the first strands.

In this case, preferably, the thickness of the cap portions is in a range of one to four times the thickness of the first strands.

Preferably, an inclination angle of the first strands to a virtual line orthogonal to the second strands is in a range of <NUM> to <NUM> degrees.

Also adoptable is a configuration in which, in a tensile shear test in which a test piece having a length of <NUM> along a longitudinal direction of the second strands and a width of <NUM> is pulled in a shear direction at <NUM>/min by a tensile testing machine while a <NUM> length along the longitudinal direction of the second strands from one edge of the test piece is engaged with a mating member through the engagement elements, a measured displacement amount of the test piece along the longitudinal direction of the second strands up to an instant when a load value in the shear direction due to the engagement of the test piece and the mating member sharply drops is <NUM>% or more of a total length that the test piece has before being pulled.

Also adoptable is a configuration in which a breaking-time load value when the test piece by itself was pulled along the longitudinal direction of the second strands at <NUM>/min by the tensile testing machine is <NUM> times or less a load value at the instant when the load value in the shear direction due to the engagement of the test piece and the mating member sharply drops in the tensile shear test.

Preferably, the thermoplastic elastomer is a thermoplastic polyester elastomer.

The touch fastener can be formed integrally with a cushioning member of a seat to be used.

The present invention further provides a method of manufacturing a touch fastener, the touch fastener including:.

In this case, the manufacture can be performed such that the thickness of the portions, of the one-side ribs, which are to form the cap portions of the second strands is made smaller than a thickness of the base layer which is to be the first strands.

Further, the manufacture can be performed such that the thickness of the portions, of the one-side ribs, which are to form the cap portions of the second strands is made equal to or more than a thickness of the base layer which is to be the first strands.

In the touch fastener of the present invention, all the elements, namely, the first strands, the second strands, and the engagement elements are formed of the thermoplastic elastomer. Further, the plurality of first strands and the plurality of second strands are disposed to intersect with each other, and consequently, hole portions each surrounded by the two adjacent first strands and the two adjacent second strands are provided. Accordingly, the touch fastener has a high elastic function, easily stretches, and has high followability to the relative movement of the portions to be engaged.

Further, according to the method of manufacturing the touch fastener of the present invention, when the sheet-shaped molded body is extruded, by varying the thickness of the portions, of the one-side ribs, which are to form the cap portions of the second strands, it is possible to manufacture touch fasteners different in tear strength in the direction substantially orthogonal to the extrusion direction.

The present invention will be hereinafter described in more detail based on an embodiment illustrated in the drawings. <FIG> and <FIG> are views illustrating a touch fastener <NUM> according to one embodiment of the present invention. As illustrated in these drawings, the touch fastener <NUM> includes first strands <NUM>, second strands <NUM>, and engagement elements <NUM>. The touch fastener <NUM> is formed using a sheet-shaped molded body <NUM> (see <FIG>) molded by an extruder. As illustrated in <FIG>, a cavity portion <NUM> of a molding die <NUM> of the extruder has a cross-sectional shape having: a middle space portion <NUM> provided at its up-down direction middle position and having a predetermined width in the width direction (in a direction orthogonal to an extrusion direction) and a height of several mm or less; a plurality of downward projecting space portions <NUM> projecting downward from the middle space portion <NUM> and formed to be predetermined-interval spaced from one another in the width direction of the middle space portion <NUM>; and upward projecting space portions <NUM> projecting upward to an opposite side of the downward projecting space portions <NUM>, and when a molding material is put therein to be extruded, a base layer <NUM> in a substantially flat plate shape is extruded from the middle space portion <NUM>, and lower surface-side ribs <NUM> which are one-side ribs and upper surface-side ribs <NUM> which are the other ribs are extruded from the downward projecting space portions <NUM> and the upward projecting space portions <NUM> respectively as illustrated in <FIG>. Consequently, the sheet-shaped molded body <NUM> is formed in which the base layer <NUM> is integrated with the lower surface-side ribs <NUM> being the one-side ribs extending in the extrusion direction on one surface of the base layer <NUM> and the upper surface-side ribs <NUM> being the other ribs extending in the extrusion direction on the other surface of the base layer <NUM>. Note that the upper surface-side ribs <NUM> are to form the engagement elements <NUM> constituted by hooks and each having, at a tip thereof, a flange portion 30a (see <FIG>) projecting outward in the width direction, for instance. Therefore, the cross-sectional shape of each of the upper surface-side ribs <NUM>, in other words, the cross-sectional shape of each of the upward projecting space portions <NUM> of the molding die agrees with the cross-sectional shape of the engagement element <NUM> illustrated in <FIG>, and is a shape having a portion 1130b, which corresponds to a stem 30b, extending in the upward direction from the middle space portion <NUM> and a portion 1130a projecting outward at an upper end portion of the portion 1130b (see <FIG>). Note that, in this embodiment, the second strands <NUM> each have a shape including a stem 20b projecting downward from the first strand <NUM> (base layer <NUM>) and a cap portion 20a projecting outward to both sides in the width direction of the stem 20b at a lower end portion of the stem 20b, and accordingly the downward projecting space portions <NUM> each have a shape including: a portion 1120b with a relatively narrow width extending in the downward direction from the middle space portion <NUM>; and a portion 1120a with a wide width projecting outward to both sides in the width direction at a lower end portion of the portion 1120b. Therefore, in the lower surface-side ribs <NUM> being the one-side ribs extruded from the downward projecting space portions <NUM>, the portions 120b extruded from the narrow-width portions 1120b form the stems 20b of the second strands <NUM> and the portions 120a extruded from the wide-width portions 1120a form the cap portions 20a of the second strands <NUM>.

As illustrated in <FIG> and <FIG>, in the extrusion-molded sheet-shaped molded body <NUM>, cuts are made from the tops of the upper surface-side ribs <NUM> down to a boundary position with the lower surface-side ribs <NUM> in the base layer <NUM> (the position indicated by the sign D in <FIG>), the cuts extending along a width direction orthogonal to the extrusion direction or along a direction inclined at a predetermined angle to the width direction and being a predetermined interval spaced from one another in the extrusion direction. The direction inclined at the predetermined angle to the width direction mentioned here is, as illustrated in <FIG>, the inclination angle θ to the virtual line E along the width direction orthogonal to the second strands <NUM>. A preferable value of the inclination angle θ will be further described later.

Next, the sheet-shaped molded body <NUM> is stretched in the extrusion direction. Consequently, as illustrated in <FIG>, the lower surface-side ribs <NUM> elongate in the stretching direction, while, in the upper surface-side ribs <NUM> and the base layer <NUM>, owing to the cuts made therein at the predetermined intervals, portions sandwiching each of the cuts separate from one another. As a result, spaces are formed between the portions sandwiching the cuts to become hole portions <NUM>. When the stretching is continued until the hole portions <NUM> come to have a predetermined size, the shape is fixed by cooling. Needless to say, at the stages of the extrusion, the stretching, and so on, appropriate heating for facilitating the working and appropriate cooling for fixing the shape after the working are applied, though not described in detail above.

Through such steps, as illustrated in <FIG> and <FIG>, the portions, of the base layer <NUM>, which are separated at the cut positions become the plurality of first strands <NUM> arranged at intervals from one another and substantially in parallel to one another, the lower surface-side ribs <NUM> become the plurality of second strands <NUM> extending along the direction intersecting with the longitudinal direction of the first strands <NUM> and arranged at intervals from one another and substantially in parallel to one another, and the portions, of the upper surface-side ribs <NUM>, which are separated at the cut positions become the discrete engagement elements (hooks) <NUM>. Accordingly, the engagement elements (hooks) <NUM> are provided to project to the opposite side of the second strands <NUM>, with the first strands <NUM> (base layer <NUM>) therebetween. Further, since the plurality of first strands <NUM> are arranged at intervals from one another and the plurality of second strands <NUM> are arranged at intervals from one another to intersect with the plurality of first strands <NUM>, the hole portions <NUM> are each formed at a position surrounded by the adjacent first strands <NUM>, <NUM> and the adjacent second strands <NUM>, <NUM> in a plan view. Next, the sheet-shaped molded body <NUM> is cut into a predetermined dimension according to the application, whereby the desired mesh-type touch fastener <NUM> is manufactured.

In this embodiment, as illustrated in <FIG> and <FIG>, the second strands <NUM> each have a shape including the stem 20b projecting downward from the first strand <NUM> (base layer <NUM>) and the cap portion 20a projecting in the width direction of the stem 20b at the lower end portion of the stem 20b. However, the second strands <NUM> (lower surface-side ribs <NUM>) are intended to connect the adjacent first strands <NUM>, <NUM> which are separated, and thus they each may have a substantially quadrangular cross-sectional shape or the like including only the stem 20b without such a cap portion 20a. However, providing the cap portions 20a makes it possible to adjust tear strength in the direction substantially orthogonal to the longitudinal direction of the second strands <NUM> (extrusion direction) depending on the thickness X1 of the cap portions 20a (the length from the boundary position with the stems 20b of the second strands <NUM> projecting downward from the first strands <NUM> to the outer end surfaces of the cap portions 20a) (see <FIG>).

Later-described tests conducted in Examples have led the present inventor to the following findings. That is, with the same material and the same dimensional parameters of portions except the thickness of the cap portions 20a, there is a tendency that the thinner the thickness X1 of the cap portions 20a, the larger the elongation along the longitudinal direction of the second strands <NUM> and the lower the tear strength in the direction substantially orthogonal to the longitudinal direction of the second strands <NUM>, while there is a tendency that the thicker the thickness X1 of the cap portions 20a, the smaller the elongation along the longitudinal direction of the second strands <NUM> and the higher the tear strength in the direction substantially orthogonal to the longitudinal direction of the second strands <NUM>. Therefore, by varying the thickness of the cap portions 20a, it is possible to provide touch fasteners <NUM> different in the tear strength in the direction substantially orthogonal to the longitudinal direction of the second strands <NUM> (extrusion direction). In other words, by using, as the molding die <NUM>, one whose wide-width portions 1120a projecting outward to both sides in the width direction at the lower end portions of the downward projecting space portions <NUM> have a relatively large up-down direction distance, it is possible to impart a relatively large thickness to the portions 120a at the lower end sides of the lower surface-side ribs <NUM> which are extruded from the wide-width portions 1120a to form the cap portions 20a of the second strands <NUM>. By using, as the molding die <NUM>, one whose wide-width portions 1120a projecting outward to both sides in the width direction at the lower end portions of the downward projecting space portions <NUM> have a relatively narrow up-down direction distance, it is possible to obtain the sheet-shaped molded body <NUM> whose portions 120a are worked to have a relatively thin thickness.

Then, in a case where emphasis is put on the elongation along the longitudinal direction of the second strands <NUM>, the thickness X1 of the cap portions 20a (the portions 120a at the lower end sides of the lower surface-side ribs <NUM>) is preferably less than the thickness X2 of the first strands <NUM> (base layer <NUM>), and more preferably in a range of <NUM>/<NUM> to <NUM>/<NUM> of the thickness X2 of the first strands <NUM>. Specifically, the thickness X1 is preferably <NUM> to <NUM> in order to satisfy both weight reduction and flexibility, and the thickness X2 is preferably <NUM> to <NUM> in view of the tear strength in the longitudinal direction.

On the other hand, in a case where emphasis is put on the tear strength in the direction orthogonal to the longitudinal direction of the second strands <NUM>, the thickness X1 of the cap portions 20a (the portions 120a at the lower end sides of the lower surface-side ribs <NUM>) is preferably equal to or more than the thickness X2 of the first strands <NUM>. However, too large a value of the thickness X1 of the cap portions 20a leads to an increase in the total thickness and weight of the touch fastener <NUM> and may make the touch fastener <NUM> difficult to handle, and therefore, the thickness X1 is more preferably in a range of one to four times, still more preferably <NUM> to <NUM> times the thickness X2 of the first strands <NUM>. Specifically, the thickness X1 is preferably <NUM> to <NUM> in view of the tear strength in the direction orthogonal to the longitudinal direction, and the thickness X2 is preferably <NUM> to <NUM> in order to satisfy both weight reduction and flexibility.

The second strands <NUM> each have the stem 20b in addition to the cap portion 20a. Therefore, in the above-described adjustment of the thickness X1 of the cap portions 20a, dimensional parameters of the entire second strands <NUM> including the stems 20b are also preferably taken into consideration. Both in the case where emphasis is put on the elongation characteristic along the longitudinal direction of the second strands <NUM> and in the case where emphasis is put on the tear characteristic in the direction substantially orthogonal to the longitudinal direction of the second strands <NUM>, the stems 20b also preferably have certain cross-sectional area and width relative to the cross-sectional area of the cap portions 20a. Therefore, preferably, the cross-sectional area Y1 of each of the cap portions 20a taken along the direction orthogonal to the longitudinal direction being the orientation direction of the second strand <NUM> is in a range of <NUM> to <NUM>% of the cross-sectional area Y2 of the entire second strand <NUM> including the cap portion 20a and the stem 20b, and the width Z1 of each of the cap portion 20a along the direction orthogonal to the longitudinal direction of the second strand <NUM> is in a range of two to six times the width Z2 of the stem 20b (see <FIG>). The cross-sectional area Y1 of the cap portion 20a is more preferably in a range of <NUM> to <NUM>% of the cross-sectional area Y2, and the width Z1 of the cap portion 20a is more preferably three to four times the width Z2 of the stem 20b.

In this embodiment, the upper surface-side ribs <NUM> and the lower surface-side ribs <NUM> are formed at positions where they face each other across the base layer <NUM> (see <FIG>). Accordingly, the engagement elements <NUM> are provided on intersections of the first strands <NUM> and the second strands <NUM> as illustrated in <FIG>, but the positions of the engagement elements <NUM> are not limited to these. That is, it is also possible to form the upper surface-side ribs <NUM> not at positions where they face the lower surface-side ribs <NUM> but at positions deviated therefrom, and as a result, provide the engagement elements <NUM> at positions deviated from the intersections of the first strands <NUM> and the second strands <NUM>.

Since the touch fastener <NUM> of this embodiment is manufactured in the above-described manner, the first strands <NUM>, the second strands <NUM>, and the engagement elements <NUM> are integrally molded, and by using a thermoplastic elastomer as their material, the first strands <NUM>, the second strands <NUM>, and the engagement elements <NUM> all have certain elasticity. As the thermoplastic elastomer, the material can be appropriately selected in consideration of the use and so on, and usable is styrene-based one, ester-based one, a nylon-based resin such as nylon <NUM> and nylon <NUM>, a polyester-based resin such as polyethylene terephthalate, polybutylene terephthalate, and polylactic acid, an ethylene-vinyl alcohol copolymer, or the like. However, a thermoplastic polyester elastomer is preferably used in view of durability, heat resistance, moldability, and so on.

Being formed of the thermoplastic elastomer, the touch fastener <NUM> of this embodiment has certain elasticity. Therefore, the touch fastener <NUM> has high followability to the relative movement of portions which are to be engaged using the touch fastener <NUM> attached thereto, and can cope with force in the shear direction owing to the elongation/contraction or deformation of the first strands <NUM>, the second strands <NUM>, and the engagement elements <NUM>, thereby capable of preventing the disengagement of the engagement elements <NUM>. Therefore, by providing the touch fastener <NUM> of this embodiment by integral molding on a member in a moving body such as an automobile, for example, a cushioning member (including a urethane pad, and so on) of a seat, to fix the cushioning member to an outer layer member, a frame, or the like, it is possible to prevent the disengagement owing to the aforesaid elongation/contraction or deformation even when a large impact load is inputted as a result of a collision or the like, to cope with the impact load. When the touch fastener <NUM> is used to join tongue pieces on the left and right sides of a foot insertion portion in an instep of a shoe, a large load is sometimes applied by a sudden movement while the wearer plays sports, and even in such a case, the touch fastener <NUM> of this embodiment can cope with the large load owing to its elastic deformation. Similarly, in a case where the touch fastener <NUM> is attached to a band-shaped supporter or the like to fix the supporter to an arm or the like, the elastic deformation makes it possible to cope with force in the shear direction caused by the movement of the arm or the like. In particular, this embodiment includes the hole portions <NUM> each surrounded by the adjacent first strands <NUM>, <NUM> and the adjacent second strands <NUM>, <NUM>, and therefore, when the aforesaid force acts, not only owing to the elastic deformation of the first strands <NUM>, the second strands <NUM>, or the engagement elements <NUM> themselves but also owing to the accompanying deformation of the hole portions <NUM>, this embodiment can exhibit higher followability to the relative movement of the portions to be engaged than a structure without the hole portions <NUM> even if both are made of the same material. The shape of the hole portions <NUM> is not limited, but preferably, the inclination angle (angle θ in <FIG>) of the first strands <NUM> to the virtual line E orthogonal to the second strands <NUM> is adjusted to a range of <NUM> to <NUM> degrees by the adjustment of the angle when the aforesaid cuts are made. If the inclination angle θ is less than <NUM> degrees, the elongation along the longitudinal direction of the second strands <NUM> is relatively easy. If the inclination angle θ is <NUM> degrees or more, especially in a range of <NUM> to <NUM> degrees, the shape becomes substantially a parallelogram or closer to a rhombus and the elongation in the width direction is relatively easy, making it easy to maintain the engagement with the mating member even if a sudden load in the width direction is applied. Thus, the direction in which the touch fastener <NUM> easily elongates can be adjusted by the inclination angle θ.

As Examples <NUM>, <NUM>, two kinds of mesh-type touch fasteners <NUM> (Example <NUM> (sample No. S-<NUM>) and Example <NUM> (sample No. S-<NUM>)) were manufactured using a PBT elastomer (manufactured by DuPont Toray Co. , product name "Hytrel" (registered trademark), product number <NUM>) as a thermoplastic polyester elastomer.

Table <NUM> shows the dimensions of portions, that is, first strands <NUM>, second strands <NUM>, and engagement elements <NUM> of Examples <NUM> and <NUM>. In Table <NUM>, "Strand <NUM>" represents the first strands <NUM>, "Strand <NUM>" represents the second strands <NUM>, and "Hook" represents the engagement elements <NUM>. Further, in Table <NUM>, the height of the engagement elements (Hook) <NUM>, Stem cross-sectional area (the area of a horizontal cross-section of stems 30b of the engagement elements <NUM> at a point where the stem width is narrowest in the height direction), the cross-sectional area of Strand <NUM> (first strands <NUM>) taken along a direction orthogonal to a longitudinal direction (the area of a cross-section in the direction orthogonal to the longitudinal direction of the second strands <NUM>), and the cross-sectional area of Strand <NUM> (second strands <NUM>) taken along the direction orthogonal to the longitudinal direction (the area of a cross-section in the width direction orthogonal to the longitudinal direction of the second strands <NUM>) were measured at the places indicated in <FIG>.

Further, the thickness X2 of the first strands <NUM> of Example <NUM> (sample No. S-<NUM>) = <NUM>, and in the second strands <NUM>, the thickness X1 of cap portions 20a = <NUM>, the height X3 of stems 20b (the distance from the boundary position D between the first strands <NUM> and the second strands <NUM> to the tops of the outer end surfaces of the cap portions 20a minus the thickness X1 of the cap portions 20a) = <NUM>, the cross-sectional area Y1 of the cap portions 20a = <NUM><NUM>, the cross-sectional area Y2 of the entire second strands <NUM> = <NUM><NUM>, the width Z1 of the cap portions 20a = <NUM>, and the width Z2 of the stems 20b = <NUM>. Ratios of these dimensional parameters were as follows: X2 : X1 = <NUM> : <NUM>, X1 : X3 = <NUM> : <NUM>, Y2 : Y1 = <NUM> : <NUM>, and Z1 : Z2 = <NUM> : <NUM>. Further, the inclination angle θ of the first strands <NUM> was <NUM> degrees as shown in Table <NUM>.

The thickness X2 of the first strands <NUM> of Example <NUM> (sample No. S-<NUM>) = <NUM>, and in the second strands <NUM>, the thickness X1 of cap portions 20a = <NUM>, the height X3 of stems 20b = <NUM>, the cross-sectional area Y1 of the cap portions 20a = <NUM><NUM>, the cross-sectional area Y2 of the entire second strands <NUM> = <NUM><NUM>, the width Z1 of the cap portions 20a = <NUM>, and the width Z2 of the stems 20b = <NUM>. Ratios of these dimensional parameters were as follows: X2 : X1 = <NUM> : <NUM>, X1 : X3 = <NUM> : <NUM>, Y2 : Y1 = <NUM> : <NUM>, and Z1 : Z2 = <NUM> : <NUM>. Further, the inclination angle θ of the first strands <NUM> was <NUM> degrees as shown in Table <NUM>.

As is apparent from the above, the dimensional parameters and the inclination angle θ of Examples <NUM> and <NUM> all fall within the ranges of the aforesaid type which puts emphasis on the elongation characteristic along the longitudinal direction of the second strands <NUM>.

An engagement force test was conducted on the touch fasteners of Examples <NUM>, <NUM>, and for comparison, the same test was conducted also on a mesh-type touch fastener manufactured using nylon (PA12) (Comparative Example <NUM> (sample No. S2771)), a mesh-type touch fastener manufactured using polypropylene (PP) (Comparative Example <NUM> (sample No. S1576)), and a touch fastener using the same PBT elastomer as that of Examples <NUM>, <NUM> but having a film structure that is not of a mesh type and having many discrete engagement elements formed on both surfaces of a base layer (Comparative Example <NUM> (sample No. S-<NUM>-<NUM>)).

Test pieces each had a <NUM> length (length along the extrusion direction, that is, length along the longitudinal direction of the second strands <NUM> in the case of the touch fastener <NUM> of this embodiment) and a <NUM> width. Peel strength was measured using a tensile testing machine (manufactured by SHIMADZU Corporation) in conformity with JIS L3416. Shear strength was measured in conformity with JIS L3416 while the touch fastener <NUM> and a mating member (loop member) were pulled in the shear direction at a tensile speed of <NUM>/min by a tensile testing machine (manufactured by SHIMADZU Corporation). Incidentally, the measurement of the shear strength was conducted while a <NUM> range in the length direction of the touch fastener <NUM> from its edge was engaged with the mating member (loop member). "ZK4030" which is the mating member (loop member) is a pile fabric manufactured by TOYO SENKO Co. , Ltd, and "E40000" is a tricot manufactured by Kuraray Fastening Co. The former has a relatively lower density of loop-forming fibers and has a softer base fabric than the latter. Table <NUM> and Table <NUM> show the results.

In Table <NUM> and Table <NUM>, an average value in five test pieces is shown for each dimensional item, and an average value in three tests is shown for each performance item.

From Table <NUM> and Table <NUM>, the peel strength and the shear strength of Examples <NUM> and <NUM> were both on similar levels as those of Comparative Example <NUM>. As compared with Comparative Example <NUM>, the peel strength was on a similar level, but the shear strength was higher in Examples <NUM> and <NUM> by <NUM> N/cm<NUM> more. This is thought to be because Comparative Example <NUM> has little elasticity. As compared with Comparative Example <NUM> made of the same material as that of Examples <NUM>, <NUM>, the peel strength was higher in Examples <NUM> and <NUM>. As for the shear strength, there was no big difference in the case where the mating member was ZK4030, but there was a big difference in the case where the mating member was E40000. This is thought to be because a difference in elasticity associated with the presence or absence of mesh has an influence, but the characteristics of the mating member also have an influence, which will be discussed later.

<FIG> each illustrate the relationship between a load (test force) and a displacement amount measured at the time of the pulling in the aforesaid shear strength test.

The touch fastener <NUM> of Example <NUM> elongated without separating from the mating member until the displacement amount reached about <NUM> to about <NUM>, and during this period, the load value in the shear direction due to their engagement reached about <NUM> N to about <NUM> N, and then the load value in the shear direction sharply dropped by several ten N or more at a stroke to reach near <NUM> N because the touch fastener <NUM> broke (see <FIG>).

The touch fastener <NUM> of Example <NUM> elongated without separating from the mating member until the displacement amount reached about <NUM> to about <NUM>, and during this period, the load value in the shear direction due to their engagement reached about <NUM> N to about <NUM> N, and then the load value in the shear direction dropped sharply by several ten N or more at a stroke to reach near <NUM> N because the touch fastener <NUM> broke (see <FIG>).

In the touch fastener of Comparative Example <NUM>, the load value in the shear direction due to its engagement with the mating member reached about <NUM> N to about <NUM> N by the time the load value dropped sharply by several ten N or more to reach near <NUM> N, but a displacement amount by which it elongated without separating from the mating member was in a range of about <NUM> to about <NUM> (see <FIG>).

In the touch fastener of Comparative Example <NUM>, in the case where the mating member (loop) was ZK4030, after the load value reached about <NUM> N at a displacement amount of about <NUM>, they started separating from each other, the loops of the mating member snapped, and the load value dropped sharply, and thereafter, hooking to other loops and snapping were repeated and after sharply rising, the load value sharply dropped again. Similarly, in the case where the mating member was E40000, after rising to about <NUM> N at a displacement amount of about <NUM>, the load value sharply dropped at a stroke to near <NUM> N and the load value remained low while they separated from each other and the loops of the mating member were snapped (see <FIG>).

From the above, it can be seen that the touch fasteners <NUM> of Example <NUM> and Example <NUM> elongate by <NUM> or more without separating from the mating member. In contrast, in Comparative Example <NUM>, which elongated most among Comparative Examples <NUM> to <NUM>, elongates by about <NUM>, and it is seen that the elongation of Example <NUM> and Example <NUM> is large. Accordingly, the touch fasteners <NUM> of Example <NUM> and Example <NUM> have a large displacement amount especially along the longitudinal direction of the second strands <NUM> and have high followability to the relative movement of the portions to be engaged. Moreover, because of the large displacement amount, they can exhibit high impact absorbing power between the portions to be engaged and thus are suitable for engaging portions to which an impact load is applied.

From these, it follows that, when the displacement amount is measured in the tensile shear test in which the test piece whose length along the longitudinal direction is <NUM> and whose width orthogonal to the longitudinal direction of the second strands is <NUM> is pulled in the shear direction while the engagement elements in a <NUM> range from its one edge in terms of the longitudinal direction of the second strands are engaged with the mating member (loop member), one in which the displacement amount along the longitudinal direction of the second strands up to the instant when the load value in the shear direction due to the engagement of the touch fastener and the mating member (loop member) sharply drops is <NUM> or more is preferable, and one in which this displacement amount is <NUM> or more is more preferable. In other words, the displacement amount in the aforesaid test is preferably about <NUM>% or more, and more preferably about <NUM>% or more of the total length that the touch fastener has before being pulled.

Regarding the touch fastener <NUM> of Example <NUM> (sample No. S-<NUM>), Table <NUM> shows dimension under tension, length when it is restored by tension cancellation (dimension under no tension), an amount of change in the dimension under tension (change in dimension under tension), elastic deformation length which is a difference between the dimension under tension and the dimension under no tension, a ratio of the elastic deformation length in the amount of change in the dimension under tension, plastic deformation length which is a difference between the amount of change in the dimension under tension and the elastic deformation length, and a ratio of the plastic deformation length in the amount of change in the dimension under tension, in the aforesaid shear strength test. As illustrated in <FIG>, L0 represents the length before the pulling, and L1 to L7 each represent the length after the pulling. Further, <FIG> is a graph in which the elastic deformation length and the plastic deformation length are compared.

From Table <NUM> and the graph in <FIG>, it can be seen that the ratio of the elastic deformation length of the touch fastener <NUM> of Example <NUM> is about <NUM>% or more up to an instant just before the touch fastener <NUM> breaks. It can also be seen from this that the touch fastener <NUM> of Example <NUM> has high elasticity and high followability to the relative movement of the portions to be engaged. Further, the ratio of the plastic deformation length gradually increases while the elongation is <NUM> or more, preferably <NUM> or more, indicating that high damping force can be exhibited even if a sudden relative movement of the portions to be engaged is caused by an impact load.

Next, the same test pieces as above were subjected to a tensile test (Kuraray Fastening method) in which the test pieces by themselves were pulled along the longitudinal direction of the second strands (extrusion direction) at a tensile speed of <NUM>/min by a tensile testing machine (manufactured by SHIMADZU Corporation). Example <NUM> (sample No. S-<NUM>), Example <NUM> (sample No. S-<NUM>), Comparative Example <NUM> (sample No. S2711), Comparative Example <NUM> (sample No. S1576), and Comparative Example <NUM> (sample No. S-<NUM>-<NUM>) are the same as above. Comparative Example <NUM> (sample No. L8972S) is film-shaped and made of a thermoplastic polyester elastomer as in Comparative Example <NUM> but is softer than Comparative Example <NUM>. Table <NUM> and Table <NUM> show dimensional changes of these test pieces, and <FIG> and <FIG> are graphs each representing the relationship between a displacement amount and a load.

In both the touch fasteners <NUM> of Example <NUM> and Example <NUM>, the displacement amount up to the instant of the breakage is <NUM> or more, and the ratio of the elastic deformation length during this period is <NUM>% or more, from which it can be seen that they are highly elastic. In Comparative Example <NUM>, the elastic deformation length up to the instant of the breakage was <NUM>% or more, but it broke before the displacement amount reached <NUM>, and thus has poor followability to the relative movement of the portions to be engaged, and since its plastic deformation length is short, Comparative Example <NUM> can be said as being lower in impact load damping characteristic than Examples <NUM> and <NUM>. Comparative Example <NUM> broke immediately after being pulled, which shows that Comparative Example <NUM> is very poor in elasticity. In contrast, Comparative Example <NUM> and Comparative Example <NUM> did not broke even when the displacement amount was <NUM>, and also they were high in the ratio of the elastic deformation length, and thus exhibited sufficient elasticity. This is because Comparative Example <NUM> and Comparative Example <NUM> are made of the same material as that of Example <NUM> and Example <NUM>, but their load values exceeded about <NUM> N when the displacement amount was about <NUM>, and when the displacement amount reached <NUM>, the load values reached <NUM> N or more, which was greatly different from the load value of about <NUM> N to about <NUM> N in Example <NUM> and Example <NUM> when they broke (at an instant when the load value sharply dropped (this means not an instant after the sharp drop but an instant immediately before the sharp drop)).

As described above, in Example <NUM> and Example <NUM>, the load at the instant when the load value sharply drops in the test in which the touch fastener is engaged with the mating member (loop member) and pulled in the shear direction is within a range of about <NUM> N to about <NUM> N. Therefore, in the case where Comparative Examples <NUM> and <NUM> in which the load exceeds about <NUM> N when the displacement amount is about <NUM> are used, the breakage of the loops of the mating member occurs early in the state in which the touch fastener is engaged with the mating member (loop member). In this case, even if the elasticity of the touch fastener itself is high, the engagement force between the portions to be engaged drops at a stroke, which is not suitable for improving the followability in the state where the portions to be engaged remain engaged. This is why the aforesaid load value (see <FIG>), which indicates the engagement force with the mating member, measured using the touch fastener of Comparative Example <NUM> drops sharply before it sufficiently elongates.

Therefore, the mesh structure including the hole portions <NUM> easily causing the deformation of the strands <NUM>, <NUM> and the deformation of the engagement elements <NUM> as in the touch fasteners <NUM> of Example <NUM> and Example <NUM> is preferable. Further, preferable is a characteristic that the breaking-time load in the tensile test conducted on the touch fastener by itself is equal to the load value (in the above example, about <NUM> N to about <NUM> N) at the instant when the load value in the shear direction due to the engagement of the touch fastener and the mating member (loop member) sharply drops in the tensile shear test, or even if it is higher than this, is <NUM> times or less. Incidentally, if the breaking-time load is too low, the engagement force decreases, and therefore, a preferable characteristic is that the breaking-time load is <NUM>% or more of the load value at the instant when the load value in the shear direction due to the engagement of the touch fastener and the mating member (loop member) sharply drops.

A mesh-type touch fastener <NUM> (sample No. S-<NUM>-<NUM>) of Example 3A was manufactured using the same PBT elastomer (manufactured by Toray DuPont Co. , product name "Hytrel" (registered trademark), product number <NUM>) as that in Examples <NUM> and <NUM>.

In Example 3A, the thickness X2 of first strands <NUM> = <NUM>, and in second strands <NUM>, the thickness X1 of cap portions 20a = <NUM>, the height X3 of stems 20b = <NUM>, the cross-sectional area Y1 of the cap portions 20a = <NUM><NUM>, the cross-sectional area Y2 of the entire second strands <NUM> = <NUM><NUM>, the width Z1 of the cap portions 20a = <NUM>, and the width Z2 of the stems 20b = <NUM>. Ratios of these dimensional parameters were as follows: X2 : X1 = <NUM> : <NUM>, X1 : X3 = <NUM> : <NUM>, Y2 : Y1 = <NUM> : <NUM>, and Z1 : Z2 = <NUM> : <NUM>. Further, the inclination angle θ of the first strands <NUM> was <NUM> degrees (see <FIG> for the positions of the signs).

As is apparent from the above, the dimensional parameters and the inclination angle θ of Example 3A are of the aforesaid type that puts emphasis on the tear strength in the direction substantially orthogonal to the longitudinal direction of the second strands <NUM>.

Tests of peel strength and shear strength were conducted as in Examples <NUM> and <NUM>. As a mating member (loop member), "ZK4030" and "E40000" which are the same as those in Examples <NUM> and <NUM> were used. The other test conditions are also the same as those in Examples <NUM> and <NUM>.

As a result, the peel strength was <NUM> N/cm in the case where ZK4030 was the mating member and was <NUM> N/cm in the case where E40000 was the mating member.

The shear strength was <NUM> N/cm<NUM> in the case where ZK4030 was the mating member and was <NUM> N/cm<NUM> in the case where E40000 was the mating member.

<FIG> illustrates the relationship between a load (test force) and a displacement amount which were measured at the time of the pulling in the aforesaid test of the shear strength.

In the touch fastener of Example <NUM>, in the case where the mating member (loop) was ZK4030, the load value reached about <NUM> to <NUM> N when the displacement amount was about <NUM> to <NUM>, and then they started separating from each other, the loops of the mating member snapped, and the load value sharply dropped. In the case where the mating member was E40000, the load increased to about <NUM> to <NUM> N by the time the displacement amount reached about <NUM> to <NUM>, and then the load value sharply dropped.

Therefore, the displacement amount along the longitudinal direction of the second strands <NUM> was smaller in Example 3A than in Example <NUM> and Example <NUM>. However, as compared with the displacement amount corresponding to the first peak of the load value in Comparative Example <NUM> in <FIG> presenting the similar load value, that in Example 3A was about twice as large, and as compared with the touch fastener without mesh, the displacement amount in the longitudinal direction of the second strands <NUM> is larger and stretchability improves owing to the mesh.

Regarding the touch fastener <NUM> of Example 3A (sample No. S-<NUM>-<NUM>), Table <NUM> shows dimension under tension, length when it is restored by tension cancellation (dimension under no tension), an amount of change in the dimension under tension (change in dimension under tension), elastic deformation length which is a difference between the dimension under tension and the dimension under no tension, a ratio of the elastic deformation length in the amount of change in the dimension under tension, plastic deformation length which is a difference between the amount of change in the dimension under tension and the elastic deformation length, and a ratio of the plastic deformation length in the amount of change in the dimension under tension, in the shear strength test. <FIG> is a graph in which the elastic deformation length and the plastic deformation length are compared.

As is seen from Table <NUM> and the graph in <FIG>, the ratio of the elastic deformation length of the touch fastener <NUM> of Example 3A was large until the displacement reached <NUM>, but thereafter, it dropped sharply, and when the displacement reached <NUM>, the partial disengagement from the mating member occurred, and after the displacement reached <NUM>, the complete disengagement from the mating member occurred. Therefore, the elongation along the longitudinal direction of the second strands <NUM> was smaller than those of Examples <NUM> and <NUM>.

Next, the same test piece as above was subjected to a tensile test (Kuraray Fastening method) in which the test piece by itself was pulled along the longitudinal direction of the second strands (extrusion direction) at a tensile speed of <NUM>/min by a tensile testing machine (manufactured by SHIMADZU Corporation). Table <NUM> shows dimensional changes of the test piece, and <FIG> illustrates a graph representing the relationship between a displacement amount and a load.

The touch fastener <NUM> of Example 3A does not break even if the displacement amount is <NUM>, but its elastic deformation ratio is <NUM> to <NUM>%, which is smaller than the values in Examples <NUM> and <NUM> shown in Table <NUM>. On the other hand, its plastic deformation ratio is <NUM> to <NUM>%, which is larger than the values in Examples <NUM> and <NUM>. Therefore, the elongation percentage along the longitudinal direction of the second strands <NUM> in the touch fastener <NUM> of Example 3A is lower than those in Example <NUM> and <NUM>, but owing to the high plastic deformation ratio, the touch fastener <NUM> of Example 3A undergoes plastic deformation when a large load is applied as external force, and is superior in the operation of damping the external force while inhibiting the breakage of the mating member.

Next, regarding a touch fastener <NUM> of Example 3B (sample No. S-<NUM>-<NUM>), which was formed of the same material and formed with the same dimensional parameters except the inclination angle θ as those of Example 3A, a tear test in conformity with JIS L-<NUM> was conducted in the longitudinal direction (lengthwise direction) of second strands <NUM> and a direction (widthwise direction) orthogonal to the longitudinal direction. The inclination angle θ in Example 3B was <NUM> degrees. As for the lengthwise direction, a cut with a predetermined length was made along the longitudinal direction of the second strands <NUM>, one side sandwiching the cut was held with chucks, of a tensile testing machine, which were disposed at positions <NUM>-degree opposite to each other, and the test piece was pulled in opposite directions to be torn. Similarly, as for the widthwise direction, a cut was made along the direction orthogonal to the second strands <NUM>, one side and the other side sandwiching the cut were held with two chucks respectively, and the test piece was pulled in opposite directions to be torn. Table <NUM> shows the measurement results of Example <NUM> (sample No. S-<NUM>) and Example 3B (sample No. S-<NUM>-<NUM>).

As is apparent from Table <NUM>, in the test piece of Example 3B, the tear strength is <NUM> to <NUM> times in the lengthwise direction and <NUM> times or more in the widthwise direction, as compared with Example <NUM>.

Next, as illustrated in <FIG>, the test piece (width of the test piece: <NUM>) of the touch fastener <NUM> of Example 3B is sewn to a cotton cloth at a position <NUM>-distant from an edge of the test piece in conformity with JIS L-<NUM>. In the sewing, a No. <NUM> sewing-machine needle and a #<NUM> sewing-machine thread are used, and a seam pitch is <NUM>. The cotton cloth and the touch fastener <NUM> are held with chucks and pulled to be broken (<NUM>/min pulling speed). Table <NUM> shows the results in the lower columns. As the value of the seam breaking stress is smaller, it indicates that elongation occurs in the touch fastener <NUM>, and Example <NUM> easily elongates in the lengthwise direction but is difficult to elongate in the widthwise direction. On the other hand, it is seen that Example 3B has the characteristic of being difficult to elongate in the lengthwise direction but easily elongating in the widthwise direction.

Next, regarding Example 3B (sample No. S-<NUM>-<NUM>) and Example 3C (sample No. S-<NUM>-<NUM>), the characteristic was found when edges on upper and lower sides, with the direction (width direction) orthogonal to the longitudinal direction of the second strands <NUM> being defined as the up-down direction, were held with <NUM>-spaced up and down chucks of a tensile testing machine and the test pieces were each pulled by <NUM> at <NUM>/minute. Incidentally, the test pieces each had a <NUM> length along the longitudinal direction of the second strands <NUM> (width of the test pieces themselves). Further, the inclination angle θ of the first strands <NUM> in Example 3C was <NUM> degrees. The same test was also conducted on Example <NUM> (sample No. <NUM>, the inclination angle θ of the first strands <NUM> = <NUM> degrees). Table <NUM> shows the results.

In Examples 3B and 3C, both the strength value and the strength per unit length are greatly lower than those in Example <NUM>. This indicates that, in the direction (width direction) orthogonal to the longitudinal direction of the second strands <NUM>, Examples 3B and 3c more easily elongate than Example <NUM>. Further, the comparison between Example 3B and Example 3C shows that Example 3C more easily elongates in the width direction. Therefore, with the inclination angle θ of a certain degree, preferably <NUM> to <NUM> degrees, and more preferably <NUM> to <NUM> degrees, the touch fastener <NUM> can have the characteristic of easily elongating in the width direction.

Regarding Example 3B (sample No. S-<NUM>-<NUM>), Example 3C (sample No. S-<NUM>-<NUM>), and Example <NUM> (sample No. <NUM>), square test pieces whose sides were each <NUM> were fabricated as illustrated in <FIG>, and they were pulled diagonally at a tensile speed of <NUM>/minute by <NUM>-distant upper and lower chucks of a tensile testing machine. As illustrate in <FIG>, the test pieces were each formed so as to easily elongate along one of the two diagonal lines, and in the measurement, this direction was defined as the "elongation direction" and the direction along the other diagonal line was defined as the "other direction". Table <NUM> shows the results.

In Examples 3B and 3C, the strength value in the "elongation direction" is larger than that in Example <NUM>, and a difference between the strength value in the "elongation direction" and that in the "other direction" is also larger than that in Example <NUM>. This indicates that the direction in which the elongation easily occurs can be controlled depending on the magnitude of the inclination angle θ.

Claim 1:
A mesh-type touch fastener (<NUM>) comprising:
a plurality of first strands (<NUM>) arranged at intervals from one another and substantially in parallel to one another;
a plurality of second strands (<NUM>) projecting from the first strands (<NUM>) outward in a thickness direction of the first strands (<NUM>), extending along a direction intersecting with a longitudinal direction of the first strands (<NUM>), and arranged at intervals from one another and substantially in parallel to one another; and
engagement elements (<NUM>) projecting from the first strands (<NUM>) to an opposite side of the second strands (<NUM>);
wherein the first strands (<NUM>), the second strands (<NUM>), and the engagement elements (<NUM>) are integrally molded of a thermoplastic elastomer,
wherein the second strands (<NUM>) each include a stem (20b) and a cap portion (20a) projecting to both sides of the stem (20b) at an end portion of the stem (20b), the mesh-type touch fastener (<NUM>) being characterized in that both of the stem (20b) and the cap portion (20a) extend along the direction intersecting with the longitudinal direction of the first strands (<NUM>), which is a longitudinal direction of the second strands (<NUM>), and
wherein both the stem (20b) and the cap portion (20a) connect adjacent first strands (<NUM>,<NUM>) which are separated.