WATERPROOF STRINGER AND WATERPROOF FASTENER

Abstract

Fastener stringer includes: a fastener tape; a fastener element arranged on a side edge portion of the fastener tape; and a covering member made of soft material and covering the fastener tape, the covering member comprising a sealing portion positioned on an opposite side of the fastener element with respect to the fastener tape in a thickness direction of the fastener tape. The covering member includes a flexible core sheet extending in a longitudinal direction of the fastener stringer. The core sheet is embedded in the soft material such that one surface of the core sheet is at least partially exposed or both surfaces of the core sheet are not exposed.

Claims

1. A waterproof stringer comprising: a fastener tape woven from at least one weft thread and plural warp threads; a coil-like element sewn to the fastener tape by a machine-sewn thread so as to be placed on a tape bottom surface of the fastener tape; and a waterproof film laminated onto a tape top surface of the fastener tape on an opposite side of the coil-like element, the fastener tape including: an element-attachment portion overlapping the coil-like element in a thickness direction of the fastener tape; and a tape main portion which is a remainder other than the element-attachment portion, the machine-sewn thread including plural floating portions each floating over the tape top surface and floating out from a ground structure of the fastener tape, each floating portion having two sinking ends which sink toward the tape bottom surface of the fastener tape as being entrained by a sewing-machine needle which pierces the ground structure of the fastener tape, wherein the ground structure of the fastener tape includes a twill weave that is formed to cross a boundary between the element-attachment portion and the tape main portion, the floating portion extends to cross a rib and/or a groove between adjacent ribs of the twill weave in the element-attachment portion, the waterproof stringer has a plurality of hollows each formed between the floating portions and corresponding to a piercing position of the sewing-machine needle, and the plurality of hollows includes one hollow positioned between adjacent ones of the ribs or plural hollows each positioned between adjacent ones of the ribs.

2. The waterproof stringer of claim 1, wherein the plural floating portions are arranged linearly, the ribs extend along diagonal straight lines relative to an arrangement direction of the floating portions, and an angle between the arrangement direction of the floating portions and an extending direction of the rib is in a range between 10 and 30.

3. The waterproof stringer of claim 1, wherein each hollow of the plurality of hollows is observed as a hollow having an area of 0.2 mm.sup.2 or less in an image showing unevenness of the tape top surface of the fastener tape.

4. The waterproof stringer of claim 1, wherein an average area of the plurality of hollows is in a range between 0.1 mm.sup.2 and 0.2 mm.sup.2 in an image showing unevenness of the tape top surface of the fastener tape.

5. The waterproof stringer of claim 1, wherein a median value in area distribution of the plurality of hollows is in a range between 0.3 mm.sup.2 and 0.6 mm.sup.2 in an image showing unevenness of the tape top surface of the fastener tape.

6. The waterproof stringer of claim 1, wherein the plurality of hollows includes at least one hollow surrounded by the floating portions and the ribs, the at least one hollow being observed in an image showing unevenness of the tape top surface of the fastener tape.

7. The waterproof stringer of claim 1, wherein the twill weave is formed across an entire area of the element-attachment portion.

8. The waterproof stringer of claim 1, wherein the twill weave is formed across an entire area of the tape main portion except for a tape edge region of the tape main portion, the tape edge region being located on an opposite side of the element-attachment portion.

9. The waterproof stringer of claim 1, wherein the twill weave includes plural sub-zones with different extending directions of the ribs.

10. The waterproof stringer of claim 1, wherein the machine-sewn thread is thicker than a width of the warp thread of the twill weave.

11. The waterproof stringer of claim 1, wherein conditions of (a) and/or (b) is satisfied: (a) an arrangement direction of the floating portions matches or is parallel to an elongation direction of the waterproof stringer; and (b) the coil-like element is sewn onto the fastener tape by double chain stitch, and the machine-sewn thread is a needle thread of the double chain stitch.

12. The waterproof stringer of claim 1, wherein each hollow of the plurality of hollows is filled at least partially by an adhesive used for the lamination of the waterproof film onto the fastener tape.

13. A waterproof fastener comprising: a pair of waterproof stringer each being the waterproof stringer of claim 1; and a slider for engaging and disengaging the pair of waterproof stringers.

14. The waterproof stringer of claim 2, wherein each hollow of the plurality of hollows is observed as a hollow having an area of 0.2 mm.sup.2 or less in an image showing unevenness of the tape top surface of the fastener tape.

15. The waterproof stringer of claim 14, wherein the twill weave is formed across an entire area of the element-attachment portion.

16. The waterproof stringer of claim 15, wherein the twill weave includes plural sub-zones with different extending directions of the ribs.

17. The waterproof stringer of claim 16, wherein the coil-like element is sewn onto the fastener tape by double chain stitch, and the machine-sewn thread is a needle thread of the double chain stitch.

18. The waterproof stringer of claim 17, wherein each hollow of the plurality of hollows is filled at least partially by an adhesive used for the lamination of the waterproof film onto the fastener tape.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0022] FIG. 1 is a schematic partial top view of waterproof fastener according to an aspect of the present disclosure.

[0023] FIG. 2 is a schematic partial bottom view of the waterproof fastener.

[0024] FIG. 3 is a partially enlarged view of FIG. 2.

[0025] FIG. 4 is schematic cross-sectional view of engaged left and right waterproof stringers, engagement heads of left and right coil-like elements meshing alternately in front-rear direction.

[0026] FIG. 5 is a schematic side view of the waterproof stringer, schematically showing a state in which the coil-like element is sewn to a ground structure of the fastener tape by machine-sewn thread.

[0027] FIG. 6 is a diagram of weave structure of fastener tape.

[0028] FIG. 7 is a schematic diagram showing piercing positions of sewing-machine needle in a part of element-attachment portion of the weave structure.

[0029] FIG. 8 is a photograph showing a top surface of waterproof chain where unevenness can be observed which is in accordance with floating portions of the machine-sewn thread on left and right sides of chain central line.

[0030] FIG. 9 is an image, observed and captured by 3D shape measuring machine, of the tape top surface of fastener tape before lamination of the waterproof film in which depth is indicated by color difference (shading in a black-and-white image).

[0031] FIG. 10 is a structure view of weave structure of element-attachment portion of fastener tape according to a comparative example.

[0032] FIG. 11 is a photograph showing a top surface of waterproof chain according to the comparative example, where unevenness can be observed which is in accordance with floating portions of the machine-sewn thread on left and right sides of chain central line.

[0033] FIG. 12 is an image, observed and captured by 3D shape measuring machine, of the tape top surface of fastener tape before lamination of the waterproof film according to the comparative example in which depth is indicated by color difference (shading in a black-and-white image).

[0034] FIG. 13 is a flowchart showing a production process of the waterproof stringer.

[0035] FIG. 14 is a schematic process diagram in which a waterproof film is laminated onto waterproof chain.

[0036] FIG. 15 is a schematic process diagram in which the waterproof film laminated onto the waterproof chain is cut by a cutter.

DESCRIPTION OF EMBODIMENTS

[0037] Hereinafter, various embodiments and features would be discussed with reference to drawings. A skilled person would be able to combine respective embodiments and/or respective features without requiring excess description, and would appreciate synergistic effects of such combinations. Overlapping descriptions among the embodiments would be basically omitted. Referenced drawings aim mainly for describing inventions and are simplified for the sake of convenience of preparation of drawings. The respective features should be appreciated as universal features not only effective to the waterproof stringer and method of producing the same presently illustrated but also effective to other various waterproof stringers and method of producing the same not illustrated herein.

[0038] In the present disclosure, a direction of movement of slider 9 for opening and closing a waterproof fastener 1 is assumed as a front-rear direction (see double-headed arrow FB in FIG. 1). A direction parallel to a width direction of the waterproof fastener 1 is assumed as a left-right direction (see double-headed arrow LR in FIG. 1). A direction parallel to a thickness direction of the waterproof fastener 1 is assumed as an up-down direction. Note that, the up-down direction is orthogonal to both front-rear and left-right directions. The up-down direction should not necessarily be a vertical direction (gravity direction). For example, when the waterproof fastener 1 is orientated such that its elongation direction matches the vertical direction, the up-down direction of the waterproof fastener 1 is included in a horizontal direction (which is orthogonal to the vertical direction). As such, directions referred in the present specification are irrelevant to the vertical direction. Note that, as described in the followings, directions other than the front-rear direction, the left-right direction, the up-down direction may be referred.

[0039] The waterproof fastener 1 is a flexible elongated part elongated in the front-rear direction with a predetermined width in the left-right direction, and has a pair of left and right waterproof stringers 2m,2n, and a slider 9 for engaging and disengaging the waterproof stringers 2m,2n. Likewise the waterproof fastener 1, the waterproof stringers 2m,2n are flexible elongated parts too elongated in the front-rear direction with a constant width in the left-right direction. As the slider 9 moves frontward, the left and right waterproof stringer 2m,2n (particularly, coil-like element 4m,4n described below) are engaged, and a waterproof seal is formed based on abutting contact between opposed side-edges 65 of the waterproof films 6m,6n described in hereinafter (see FIG. 4). As the slider 9 moves rearward, the left and right waterproof stringer 2m,2n (particularly, the coil-like element 4m,4n described below) are disengaged, and the opposed side-edges of the waterproof film 6m,6n are also released from the abutting contact. Note that the abutting contact between the side-edges 65 of the waterproof films 6m,6n does not present a high endurance against water pressure, but some level of waterproofness may be achievable. It may be possible to omit the abutting contact between the side-edges 65 of the waterproof films 6m,6n, resulting in reduced waterproofness in this case.

[0040] The waterproof stringer 2m,2n has a fastener tape 3m,3n: a coil-like element 4m,4n sewn onto the fastener tape 3m,3n by a machine-sewn thread 5 so as to be placed on a tape bottom surface 31 of the fastener tape 3m,3n; and a waterproof film 6m,6n laminated onto a tape top surface 32 of the fastener tape 3m,3n on the opposite side of the coil-like element 4m,4n. The waterproof stringer 2m,2n has a hardness and softness in accordance with the stacking of the waterproof film 6m,6n and the fastener tape 3m,3n. The waterproof film 6m,6n supports the fastener tape 3m,3n, thus allowing a selection from a wide variety of ground structures of the fastener tape 3m,3n. In some cases, a weave structure is selected which enhances softness of the fastener tape 3m,3n, and this enhanced softness of the fastener tape 3m,3n may be compensated by the hardness of the waterproof film 6m,6n.

[0041] The fastener tape 3m,3n includes an element-attachment portion 33 on which the coil-like element 4m,4n is placed and overlaps the coil-like element 4m,4n in the thickness direction of the fastener tape 3m,3n; and a tape main portion 34 which is a remainder other than the element-attachment portion 33. The element-attachment portion 33 may be narrower than the tape main portion 34. Boundary P1 between the element-attachment portion 33 and the tape main portion 34 may be defined in a plane that is parallel to the central plane CP of the waterproof fastener 1 and in contact with a return portion 44 of the coil-like element 4m,4n described hereinbelow. The central plane CP of the waterproof fastener 1 includes an axial line defining a movement path for the slider 9 and is orthogonal to the width direction (i.e. the left-right direction) of the waterproof fastener 1. As the left and right coil-like elements 4m,4n are engaged, a slit is formed between the opposed side-edges 36 of the left and right fastener tapes 3m,3n. This slit is fully or partially covered by the waterproof films 6m,6n, thus some level of waterproofness is achieved.

[0042] The fastener tape 3m,3n is a woven fabric with higher softness woven from at least one weft thread 38 and plural warp threads 39. Automatic loom may be used for weaving the fastener tape 3m,3n. The weft thread 38 and the warp threads 39 are a thread (e.g. monofilament thread or multifilament thread) with desired characteristic (denier value, color). Before weaving the fastener tape 3m,3n, the weft thread 38 and the warp threads 39 may be dyed, or the fastener tape 3m,3n may be dyed after they are woven. The weft thread 38 may be interlaced with the warp threads 39 for each bundle of two weft-thread portions thereof being pulled together in the weft direction, but no limitation should be placed on this aspect. It may be possible that the weft thread 38 is interlaced by the warp threads 39 for each single weft thread portion thereof. Note that, the fastener tape 3m,3n is a woven fabric woven from the weft thread 38 and the warp threads 39 described above, thus allowing water permeation and penetration through the threads themselves and through the apertures between the threads.

[0043] In FIG. 4, the tape bottom surface 31 and the tape top surface 32 of the fastener tape 3m,3n are depicted as a flat surface, but they are non-flat surfaces actually. Every or each warp thread 39 included in the fastener tape 3m,3n repeats crossing above the weft thread 38 (i.e. on the side of the tape top surface 32) and crossing beneath the weft thread 38 (i.e. on the side of the tape bottom surface 31). Floating and sinking of each warp thread 39 as noted above spread in the width direction of the fastener tape 3m,3n, thus allowing the tape bottom surface 31 and the tape top surface 32 to have two-dimensionally distributed unevenness.

[0044] The coil-like element 4m,4n typically consists of a wounded coil-like monofilament, and includes a series of units U1 each consisting of upper leg 41, lower leg 42, engagement head 43, and return portion 44 (See FIGS. 3-5). The upper leg 41 and the lower leg 42 extend in the width direction of the fastener tape 3m,3n, and have outward and inward ends regarding the fastener tape. The engagement head 43 extends in the up-down direction so as to interconnect the outward ends of the upper and lower legs 41 and 42 regarding the fastener tape. The return portion 44 extends and curves so as to interconnect the inward ends of the lower and upper legs 42 and 41 between the adjacent units U1. Note that the outward regarding the fastener tape indicates, regarding one fastener tape, a direction directed from a point positioned on the tape surface of the fastener tape to a point positioned externally of the tape surface of the fastener tape, and may cross (e.g. be orthogonal to) the opposed side-edge 36 in some cases. Note that the inward regarding the fastener tape indicates, regarding one fastener tape, a direction directed from a point positioned externally of the tape surface of the fastener tape to a point positioned on the tape surface of the fastener tape, and may cross (e.g. be orthogonal to) the opposed side-edge 36 in some cases. The engagement head 43 has a meshing portion (biting portion) molded to have a wider width in the front-rear direction through plastic deformation of the monofilament, allowing the engagement of the left and right coil-like elements 4m,4n.

[0045] The coil-like element 4m,4n may be variously sewn to the fastener tape 3m,3n by the machine-sewn thread 5. Typical situations including the depicted example, the coil-like element 4m,4n is sewn to the fastener tape 3m,3n by double chain stitch or lock stitch based on operation of the sewing machine. The sewing-machine needle of the sewing machine reciprocates in the up-down direction so as to penetrate through the fastener tape 3m,3n, and a looper of the sewing machine moves along the front-rear direction so that a looper thread is entangled with a lower loop of the needle thread. Moreover, a feeding mechanism of the sewing machine continuously or intermittently feeds the fastener tape 3m,3n and the coil-like element 4m,4n in the front-rear direction. In a case of double chain stitch, two sewing-machine needles are preferably used to form two lines of stitches on the tape top surface 32, but the number of sewing-machine needle would be changed as desired.

[0046] As the sewing-machine needle pierces the fastener tape 3m,3n, the ground structure of the fastener tape 3m,3n is deformed, e.g. the weft thread 38 thereof slightly moves (i.e. escapes) in the front-rear direction (feeding direction) and/or the warp thread 39 thereof slightly moves (i.e. escapes) in the tape width direction (the left-right direction). The feeding speed of the sewing machine may be set to be constant, and the sewing-machine needle may pierce the fastener tape 3m,3n at a predetermined interval along the elongation direction of the fastener tape 3m,3n. It should be noted that the piercing positions of the sewing-machine needle may fluctuate slightly in accordance with feeding accuracy of the sewing machine, slipping and tape softness and the like. Note that, in an exemplary example, the sewing-machine needle pierces into and is pulled out from the fastener tape 3m,3n which is stationary during the transportation.

[0047] In the above-described case, the machine-sewn thread 5 includes at least two different threads such as the needle thread 51 and the looper thread 56, and these threads are regularly entangled so that the coil-like element 4m,4n is secured to the fastener tape 3m,3n. The needle thread 51 includes a plurality of floating portions 52 each floating over the tape top surface 32 and floating out from the ground structure of the fastener tape 3m,3n (see FIG. 5). Each floating portion 52 has two sinking ends 52a,52b which sink toward the tape bottom surface 31 of the fastener tape 3m,3n as being entrained by the sewing-machine needle 8 which pierces the ground structure of the fastener tape 3m,3n. Typically, the plurality of floating portions 52 may be arranged in a direction matching or parallel to the elongation direction of the waterproof stringer 2m,2n (i.e. linearly), but should not be limited to this. The waterproof stringer 2m,2n has a plurality of hollows 7 each interposed between the floating portions 52 and corresponding to the piercing positions of the sewing-machine needle 8. More detail discussion on the hollow 7 may follow hereinbelow.

[0048] Additionally to the floating portions 52 described above, the needle thread 51 includes a thread portion 53 that extends downward: a thread portion 54 entangled with the looper thread 56; and a thread portion 55 that extends upward, for a purpose of interconnecting the sinking end 52a and the sinking end 52b of adjacent floating portions 52. That is, the needle thread 51 is a meandering thread including a series of alternate upper and lower loops, the upper loop including the floating portion 52 and the lower loop including the thread portion 54. Depicted is that the thread portion 53 and the thread portion 54 are in direct contact, but it should not be limited to this manner. Furthermore, the interlacing point 57 where the needle thread 51 and the looper thread 56 are entangled is positioned closer to the lower leg 42 than the upper leg 41 in the up-down direction, but should not be limited to this.

[0049] The tension of the needle thread 51 may be adjusted by regulating the amount of feeding the needle thread 51 for each up-down motion of the sewing-machine needle 8, and this equally applies to the looper thread 56. In either way, the needle thread 51 and the looper thread 56 are entangled so that the needle thread 51 and the looper thread 56 would have a prescribed tension or a tension within a prescribed range. As a result of this, the ground structure of the fastener tape 3m,3n may be deformed due to the needle thread 51 itself in addition to the piercing of the sewing-machine needle 8 (escaping from the sewing-machine needle 8), e.g. its weft thread 38 is pushed to displace (typically slightly) in the front-rear direction and/or its warp thread 39 is pushed to displace (typically slightly) in the left-right direction. These local movement of the threads facilitates formation of the hollows 7 described below. Note that, it is not a requisite to allow the needle thread 51 and the looper thread 56 to be entangled by moving the sewing-machine needle 8 downward for every unit U1 of the coil-like element. For example, the sewing-machine needle 8 can be moved downward for every two or three units U1 so as to allow the needle thread 51 and the looper thread 56 to be entangled.

[0050] Typically, the waterproof film 6m,6n is a film having a prescribed thickness and made of thermoplastic resin. As the thermoplastic resin, at least one selected from a group consisting of Polyurethane, Polyester, Polyethylene, Polypropylene and Polyvinyl alcohol may be employed, for example. The waterproof film 6m,6n may be laminated onto the fastener tape 3m,3n via an adhesive exemplarily, but it may be laminated onto the fastener tape 3m,3n through surface-melting or coating or the like. That is, methods other than the adhesive may be employed for a purpose of the lamination of the waterproof film 6m,6n onto the fastener tape 3m,3n. In a preferred example, the waterproof film includes polyurethane, and the adhesive includes water-based polyurethane adhesive as presented in PTL 1 (the PTL is herein incorporated by reference in its entirety).

[0051] Referring to FIG. 6, the ground structure of the fastener tape 3m,3n includes a twill weave 35 formed to cross the boundary P1 between the element-attachment portion 33 and the tape main portion 34. Preferably, the twill weave 35 includes a plurality of ribs 26 extending to cross the boundary P1 between the element-attachment portion 33 and the tape main portion 34. This allows that difference becomes less apparent between the both sides of the boundary P1 in connection to the laminated condition between the ground structure and the waterproof film 6m,6n, thus enhancing uniformity of appearance and/or degree of surface flatness of the waterproof stringer 2m,2n. The surface flatness may be determined by calculating a surface roughness of the waterproof film 6m,6n.

[0052] In more detail, the twill weave 35 includes a first zone 35a formed to cross the boundary P1 between the element-attachment portion 33 and the tape main portion 34, and a second zone 35b of the remainder. The first zone 35a includes a plurality of ribs 26 extending to cross the boundary P1. The second zone 35b includes a tape edge region 35r situated on the opposite side of the element-attachment portion 33 of the tape main portion 34, and a plurality of sub-zones 35p,35q with different extending directions of the ribs 26 (e.g. opposite directions). The tape edge region 35r consists of a plain weave, but other type of weaves may be employed. In the sub-zone 35p, the ribs 26 extend diagonally so as to be away from the element-attachment portion 33 as extending along the warp direction. In the sub-zone 35q, the ribs 26 extend diagonally so as to be close to the element-attachment portion 33 as extending along the warp direction. That is, the sub-zones 35p,35q have the ribs 26 which are in a relationship of mirror image. As such, the softness and the like of the ground structure may be adjustable based on the sub-zones with different extending directions of the ribs 26. Note that, the twill weave may be used for a purpose of obtaining a constant hardness while maintaining a higher softness.

[0053] In some cases, the entire area of the element-attachment portion 33 consists of the twill weave, but should not be limited to this. Additionally or alternatively, the entire area of the tape main portion 34 except for the tape edge region 35r consists of the twill weave, but should not be limited to this. Larger area of the twill weave may ensure that the machine-sewn thread is more reliably pierced into the twill weave and simultaneously facilitate higher surface flatness of the waterproof stringer 2m,2n (in turn, improved appearance thereof) as would be appreciated based on comparison between FIGS. 8 and 11. The fastener tape 3m,3n shown in FIG. 8 consists of a twill weave in its entire area except for the tape edge region 35r. The fastener tape shown in FIG. 11 does not include a twill weave in its tape main portion and thus, as shown in FIG. 11, the surface of the waterproof stringer has noticeable unevenness when comparing it with one shown in FIG. 8 and its flatness is reduced.

[0054] FIG. 7 shows a weave structure on the side of the tape top surface 32 of the fastener tape 3m,3n. In the diagram of weave structure of FIG. 7, the grid cells are arranged two-dimensionally in the row and column directions. The row direction matches the weft direction the weft thread extends, and the column direction matches the warp direction the warp thread extends. Note that in cases where the warp thread crosses every two weft thread portions pulled together in the tape width direction, each grid cell includes the two weft-thread portions. The number of warp thread included in each grid cell may be one, but should not be limited to this. The hatched rectangular grid cells indicate the floating portions 52 of the warp threads 39. The ribs 26 are formed by the floating portions 52 of the warp threads 39 which are continuously arranged in a diagonal direction relative to the weft thread 38. The extending direction D1 of the rib 26 may be defined by interconnecting, by a straight line, central points of the respective floating portions 52 in the front-rear direction. Grooves 27 may be formed between the adjacent ribs 26 in the warp direction which extend diagonally similar to the ribs 26.

[0055] In FIG. 7, parallel two dotted lines represent the needle threads 51 of a prescribed thickness, and dotted circles represent piercing positions of the sewing-machine needle 8. There is the floating portion 52 of the needle thread 51 between the dotted circles. The piercing positions of the sewing-machine needle 8 are assumed to be positioned within the dotted circles, but may slightly deviate from the dotted circles. In the view of weave structure of FIG. 7, the floating portion 52 extends to cross the rib 26 (similarly the groove 27 between the ribs 26) of the twill weave in the element-attachment portion 33. Moreover, piercing positions of the sewing-machine needle 8 are located between the adjacent ribs 26 along the warp direction (see P1-P5 and the like in FIG. 7, for example), and the hollows 7 would be positioned between the adjacent ribs 26. The hollow 7 may have a reduced spatial size (capacity) due to the bulging of the rib 26, and the hollow 7 may be formed to have a smaller area when observed from the above. In contrast, in cases where the element-attachment portion 33 consists of plain weave, there is no rib itself. Therefore, the hollow 7 would never be downsized and reduced into a smaller area by the rib. In a case where the element-attachment portion 33 consists of rib weave (rep), the spatial size of the hollow 7 would be enlarged as the weft thread easily moves in the warp direction when tension is applied to the machine-sewn thread 5 for a purpose of securement of the coil-like element. Therefore, similar effects as those of the present embodiment would not be obtainable. Note that, the above-noted hollows 7 may be observed as white-opaque areas when observed from the side of the top surface of the waterproof chain as shown in FIG. 8.

[0056] In the present embodiment, the waterproof stringer 2m,2n has the plurality of hollows 7 each being formed between the floating portions 52 and corresponding to the piercing position of the sewing-machine needle 8, and the plurality of hollows 7 includes one hollow 7 positioned between the adjacent ones of the ribs 26 or two or more hollows 7 each positioned between the adjacent ones of the ribs 26 (typically plural hollows 7 each positioned between the adjacent ones of the ribs 26). According to this aspect, the hollow 7 may be formed to have smaller size and smaller area between the floating portions 52 due to the ribs 26 of the ground structure of the fastener tape 3m,3n. Accordingly, it may be suppressed that air remains in the hollow 7 regardless of the use and non-use of adhesive when the waterproof film 6m,6n is laminated onto the tape top surface 32 of the fastener tape 3m,3n which otherwise results in the deteriorated appearance of the waterproof stringer 2m,2n (e.g. whitish appearance at the spot of the hollow). In this way, it may be avoided or suppressed that the yield rate is reduced due to non-sophisticated appearance of the waterproof stringer 2m,2n and at the same time, a quality appearance be added to the waterproof stringer 2m,2n. As an additional or alternative effect, the machine-sewn thread 5 extends along the rib 26 (i.e. does not extend so as to be orthogonal to the rib 26), thus reducing an extent of floating appearance of the machine-sewn thread 5 over the ground structure. As an additional or alternative effect, the hollow 7 is formed to have smaller area as described above, allowing use of thicker machine-sewn thread 5 (i.e. with greater denier) which otherwise results in the hollow 7 having a greater area. The use of thicker machine-sewn thread 5 may enhance the attachment strength of a coil-like element or allow attachment of a coil-like element having a greater size. In some cases, the machine-sewn thread 5 is a thread that is bulky relative to the width of the warp thread of the above-described twill weave, preferably a twisted multi-filament thread. Typically, the machine-sewn thread 5 is a twisted multi-filament thread having a substantially circular shape in the cross section. Note that the ribs 26 which contribute to the smaller size and smaller area of the hollow 7 may be positioned on the both sides of the hollow 7 in the tape width direction (weft direction).

[0057] Further discussion follows on various effects with reference to FIGS. 8 and 9. FIG. 8 is a photograph showing the top surface of waterproof chain where unevenness can be observed which is in accordance with floating portions of the machine-sewn threads on left and right sides of the chain central plane CP. FIG. 9 is an image, observed and captured by 3D shape measuring machine (one-shot 3D shape measuring machine (VR-3200) produced by Keyence), of the tape top surface of fastener tape before lamination of the waterproof film in which depth is indicated by color difference (shading in a black-and-white image). Comparative example is referred here for facilitated understanding. In the comparative example, an element-attachment portion of fastener tape includes the weave structure of FIG. 10 (i.e. does not include a twill weave). In the comparative example, a tape main portion also does not include a twill weave. FIG. 11 is a photograph showing a top surface of waterproof chain according to the comparative example. FIG. 12 is an image, observed and captured by 3D shape measuring machine (the same one as the working example), of the tape top surface of fastener tape before lamination of the waterproof film according to the comparative example in which depth is indicated by color difference (shading in a black-and-white image). Note that in both cases of the working and comparative examples, the waterproof film 6m,6n is laminated onto the fastener tape 3m,3n via an adhesive. Moreover, the working and comparative examples use the same material except for the difference in the weave structure of the fastener tape; and they are produced through the same production process and are observed under the same condition and by the same device. Note that in the both cases of the working and comparative examples, machine-sewn threads (the needle thread and the looper thread) are used which are thicker than the warp thread and the weft thread.

[0058] In both FIG. 8 and FIG. 11, ridges are observed which are in accordance with the floating portions of the needle thread on the both sides of the central plane CP of the waterproof chain. In the FIG. 11, white-opaque areas are formed around a number of floating portions. In FIG. 11, not only at the intervening spots between the floating portions, there are even slightly longer white-opaque areas each of which is formed to extend along the floating portion. In contrast, there are slight white-opaque areas at the intervening spots between the floating portions in FIG. 8 but, these are smaller in area relative to those shown in FIG. 11. Moreover, no slightly longer white-opaque area extending along the floating portion is formed in FIG. 8.

[0059] In both FIG. 9 and FIG. 12, the hollows 7 formed between the floating portions 52 are observable. In FIG. 9 and FIG. 12, dotted lines are drawn on the respective contours of the floating portions 52 which are adjacent in the warp direction, and a solid line is drawn on a contour of the hollow 7 between those floating portions 52. The dotted and solid lines are not drawn for every floating portion and ever hollow, but would be similarly assumable. As would be understood by comparing FIG. 9 and FIG. 12, an area of the hollow 7 observed in FIG. 9 is smaller than an area of the hollow 7 observed in FIG. 12. Average of area may be used for the comparison of area.

[0060] In more detail, in either of the working and comparative examples, two lines of stitches L1,L2 (each consisting of a series of floating portions) are formed in each of the waterproof stringers 2m,2n. In FIG. 9, each hollow 7 is formed between adjacent floating portions 52 of the respective line of stitches L1,L2. In FIG. 12, a smaller number of hollows 7 are formed on the line of stitches L1, and a greater number of larger sized hollows 7 are formed on the line of stitches L2. In FIG. 12, the number and area of hollow may be suppressed on the line of stitches L1 on one side, but the greater number of hollows having a larger area are formed on the line of stitches L2 on the other side, resulting in deteriorated appearance of the waterproof stringer as a whole. In the working example, the hollows 7 having a smaller area are formed on both lines of stitches L1,L2, resulting in the improvement of appearance of waterproof stringer. There is an outstanding practical advantage of improved appearance of waterproof stringer based on the modification of weave structure of fastener tape without changing the amount of adhesive. Use of increased amount of adhesive may potentially result in increased hardness of the waterproof stringer.

[0061] Preferably, the rib 26 may extend along diagonal straight lines relative to an arrangement direction of the floating portions 52 (i.e. extending direction of the stitches), and an angle between the arrangement direction of the floating portions 52 and the extending direction of the rib 26 (i.e. D1) may be any angle in a range between 10 and 30 (i.e. an angle at 10, 30 or intermediate value). Note that the intermediate value should not be limited to a natural number such as 11, 12, . . . 28, 29. In this case, the angular difference between the floating portion 52 and the rib 62 becomes lesser (i.e. both aligned into near-parallel relationship), and the surface flatness of the waterproof stringer 2m,2n may be enhanced so that the appearance is improved. Reduction in the angle of the rib 26 may cause corresponding reduction in the softness of the fastener tape (i.e. the fastener tape may have increased hardness), and this may potentially cause increased sliding resistance of the slider while it is in contact with the fastener tape. Therefore, the above-described angle is preferably 15 or more, or 20 or more. Advantageously, the angle between the arrangement direction of the floating portions 52 and the extending direction of the rib 26 is equal to an angle in a range between 15 and 30 or in a range between 20 and 30.

[0062] The number of the warp threads per a unit width (e.g. 4 mm) would be suitably set for a purpose of setting an angle of the above-described rib 26. In some cases, 10 to 20 preferably 14 to 18 warp threads per the unit width of 4 mm may be introduced in the element-attachment portion 33.

[0063] The following features would be appreciated from the image of FIG. 9 obtained by the 3D shape measuring machine (specifically, the image showing unevenness of the tape top surface 32 of the fastener tape 3m,3n before lamination of the waterproof film 6m,6n). Of course, similar optical observation can be done after peeling off the waterproof film 6m,6n by using a suitable solvent even after the lamination of the waterproof film 6m,6n. Similar optical observation can be done without peeling off the waterproof film 6m,6n depending on a type and setting of the 3D shape measuring machine. [0064] (a) Each (or every) of the plurality of hollows is observed as a hollow having an area of 0.2 mm.sup.2 or less. This feature is a result of reduced space of the hollow due to the swelling/bulge of the rib. This increases a possibility of filling of the hollow by the adhesive without increasing the amount of adhesive to be used, likely resulting in the improved appearance of the waterproof stringer. [0065] (b) Average area of the plurality of hollows is in a range between 0.1 mm.sup.2 and 0.2 mm.sup.2. This facilitates the improved appearance of the waterproof stringer more effectively. [0066] (c) Median value in the area distribution of the plurality of hollows is in a range between 0.3 mm.sup.2 and 0.6 mm.sup.2. This facilitates the improved appearance of the waterproof stringer more effectively. [0067] (d) At least one hollow surrounded by the floating portions and the ribs is observed. In FIG. 9, the hollow defined by the solid line on the line of stitches L1 is surrounded by the floating portions 52 positioned on the front and rear sides in the warp direction and the ribs 26 positioned on the left and right sides in the weft direction. In FIG. 12, due to the difference of the weave structure of the element-attachment portion, no hollow surrounded by the floating portions and the ribs as noted above is observed. It should be noted that this feature is identifiable through observation of the image other than the image of FIG. 9 or through the microscope.

[0068] Advantageously, every hollow 7 is filled at least partially by the adhesive used for the lamination of the waterproof film 6m,6n onto the fastener tape 3m,3n, but should not be limited to this. It is envisioned that some hollows of a multiplicity of hollows 7 are not filled by the adhesive at all. For example, there are situations where the waterproof stringer, which is an intermediate product with respect to production of waterproof fastener 1, is partially removed for a purpose of attaching the slider 9. In such removed portion, the adhesive may not be applied or lesser amount of adhesive is applied, resulting in locally deteriorated appearance of the waterproof stringer.

[0069] Finally, a method of production of waterproof stringer would be discussed briefly. FIG. 13 is a flowchart showing a production process of the waterproof stringer. FIG. 14 is a schematic process diagram in which a waterproof film is laminated onto waterproof chain. FIG. 15 is a schematic process diagram in which the waterproof film laminated onto the waterproof chain is cut by a cutter.

[0070] Firstly, the fastener tape is woven from the weft thread and the warp threads (S1). Advantageously, its entire structure consists of the twill weave except for the tape edge region of the tape main portion 34. The twill weave may include plural zones including ribs extending in different directions as noted above. Next, the coil-like element is sewn to the fastener tape (S2). For this purpose, an industrial sewing machine may be used. The coil-like element may be sewn to the fastener tape such by double chain stitch or lock stitch or the like. Next, the waterproof film is laminated onto the fastener tape (S3). The adhesive may be applied as a layer onto the tape top surface of the fastener tape before the lamination. A greater number of hollows may be formed to have a smaller area owing to the ribs 26, and would be more sufficiently filled by the adhesive. The same effect may be obtained when the waterproof film is melted at its surface for attachment.

[0071] As shown in FIG. 14 and FIG. 15, the waterproof film is laminated onto the fastener chain in which the waterproof stringers 2m,2n are engaged, followed by cutting the waterproof film by a cutter 81 at a position over the slit between the left and right fastener tapes 3m,3n.

[0072] Based on the above teachings, those skilled in the art may make various changes to each embodiment and each feature. The codes incorporated in the claims are for reference only and should not be referred to for a purpose of limiting the scope of claims.

REFERENCE CODE

[0073] 1 Waterproof fastener [0074] 2m,2n: Waterproof stringer [0075] 3m,3n: Fastener tape [0076] 4m,4n: Coil-like element [0077] 5: Machine-sewn thread [0078] 6m,6n: Waterproof film [0079] 7: Hollow [0080] 8: Sewing-machine needle [0081] 9: Slider [0082] 26: Rib [0083] 27: Groove [0084] 31: Tape bottom surface [0085] 32: Tape top surface [0086] 33: Element-attachment portion [0087] 34: Tape main portion [0088] 35: Twill weave [0089] 35p: Sub-zone [0090] 35q: Sub-zone [0091] 35r: Tape edge region [0092] 38: Weft thread [0093] 39: Warp thread [0094] 51: Needle thread [0095] 52: Floating portion [0096] 52a: Sinking end [0097] 52b: Sinking end