FASTENER TAPE AND METHOD FOR MANUFACTURING SAME, AND FASTENER STRINGER

Abstract

Core portion is arranged in a side-edge portion of a fastener tape to which fastener elements are to be attached. The core portion includes at least one core thread and a tubular portion that encloses the at least one core thread. The at least one core thread includes a crimpable thread that is crimped in accordance with a difference in thermal shrinkage ratio between different polymer materials.

Claims

1. A fastener tape comprising: a fastener tape having a side-edge portion to which fastener elements are to be attached; and a core portion arranged in the side-edge portion, wherein the core portion includes at least one core thread and a tubular portion that encloses the at least one core thread, the at least one core thread includes a crimpable thread that is crimped in accordance with a difference in thermal shrinkage ratio between different polymer materials.

2. The fastener tape of claim 1, wherein the core portion includes total N (N indicates a natural number of 2 or more) core threads as said at least one core thread, and each of the total N core threads is the crimpable thread.

3. The fastener tape of claim 1, wherein the crimpable thread is a composite thread of bonded filaments of at least two types of polymer materials having different thermal shrinkage ratios.

4. The fastener tape of claim 1, wherein the crimpable thread is a composite thread including at least two types of polymer materials spun together and having different thermal shrinkage ratios.

5. The fastener tape of claim 1, wherein the crimpable thread is crimped like a helix and/or wave.

6. The fastener tape of claim 1, wherein the core portion is a core yarn being woven in the fastener tape.

7. The fastener tape of claim 1, wherein the tubular portion includes a knitted structure of knitted plural skin threads.

8. The fastener tape of claim 1, wherein except for said at least one core thread, no crimpable thread is included which is crimped in accordance with a difference in thermal shrinkage ratio between different polymer materials.

9. A fastener stringer comprising: the fastener tape of claim 1; and the fastener elements attached to the side-edge portion of the fastener tape.

10. A method for manufacturing a fastener tape comprising: configuring a fastener tape provided with a core portion arranged in one side-edge portion thereof, the core portion including at least one core thread and a tubular portion that encloses the at least one core thread, and the at least one core thread including a crimpable thread that is crimped in accordance with a difference in thermal shrinkage ratio between different polymer materials; and heating the fastener tape to allow the crimpable thread to crimp.

11. The method for manufacturing a fastener tape of claim 10 further comprising: after said heating the fastener tape, stretching the fastener tape along its longitudinal direction so as to lower a degree of crimp of the crimpable thread.

12. The method for manufacturing a fastener tape of claim 11, wherein the fastener tape runs in a passage defined by plural rollers while a tension is applied thereto in the longitudinal direction, and is thereby stretched.

13. The method for manufacturing a fastener tape of claim 11 further comprising: after said stretching the fastener tape, reheating the fastener tape so as to increase the degree of crimp of the crimpable thread.

14. The method for manufacturing a fastener tape of claim 13 further comprising: dyeing the fastener tape, said reheating the fastener tape is conducted by heating and drying the fastener tape.

15. The method for manufacturing a fastener tape of claim 10 wherein after said heating the fastener tape, at least one process of lowing a degree of crimp of the crimpable thread and at least one process of increasing the degree of crimp of the crimpable thread are conducted simultaneously or in this order.

16. The fastener tape of claim 1, wherein the core portion includes total N (N indicates a natural number of 2 or more) core threads as said at least one core thread, and each of the total N core threads is the crimpable thread, the crimpable thread being a composite thread of bonded filaments of at least two types of polymer materials having different thermal shrinkage ratios.

17. The fastener tape of claim 16, wherein the crimpable thread is a composite thread including at least two types of polymer materials spun together and having different thermal shrinkage ratios.

18. The fastener tape of claim 16, wherein the crimpable thread is crimped like a helix and/or wave.

19. The fastener tape of claim 16, wherein the core portion is a core yarn being woven in the fastener tape.

20. The fastener tape of claim 16, wherein the tubular portion includes a knitted structure of knitted plural skin threads.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0025] FIG. 1 is a schematic elevational view of a slide fastener according to an aspect of the present disclosure.

[0026] FIG. 2 is a schematic diagram showing a condition where a fastener element is attached to a side-edge portion of fastener tape.

[0027] FIG. 3 is a schematic diagram showing a structure of side-edge portion of fastener tape, illustration of the fastener elements omitted.

[0028] FIG. 4 is a schematic elevational view of fastener stringer in Plus-biased state of fastener stringer.

[0029] FIG. 5 is a schematic elevational view of fastener stringer showing that the fastener stringer is shifted from Plus-biased state of fastener stringer to Zero-biased state of fastener stringer due to constriction associated with sewing.

[0030] FIG. 6 is a schematic diagram showing that a tubular portion of core portion is formed from a knitted structure.

[0031] FIG. 7 is an expanded schematic diagram of one core thread.

[0032] FIG. 8 is a schematic diagram of two crimpable core threads prior to thermal setting.

[0033] FIG. 9 is a schematic diagram of two crimpable core threads after thermal setting where a degree of crimp per a unit length (e.g. a number of helical portions per a unit length) is increased relative to the one shown in FIG. 8.

[0034] FIG. 10 is a schematic diagram of crimpable thread which is crimped into a wave.

[0035] FIG. 11 is a schematic view of a procedure of load test.

[0036] FIG. 12 is a graph showing a result of load test.

[0037] FIG. 13 is a schematic flowchart of a method for manufacturing a fastener tape.

[0038] FIG. 14 is a schematic diagram showing a condition where a fastener tape runs in a passage defined by rollers.

[0039] FIG. 15 is a schematic view showing another embodiment where crimpable threads are enclosed as core thread in a double weave (hollow weave) of side-edge portion of fastener tape.

[0040] FIG. 16 is a schematic view of another example where a core portion is woven into the fastener tape on the opposite side of a coil element.

DESCRIPTION OF EMBODIMENTS

[0041] 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 descriptions, 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 presently presented fastener tape and method for manufacturing the same, and fastener stringer but also effective to other various fastener tapes and methods for manufacturing the same, and fastener stringers not presented in the present specification.

[0042] In the present specification, direction-related terms of front-rear, left-right and up-down directions may be referred. The front-rear direction matches a direction of movement of slider 9 for opening and closing slide fastener 1, and is identical to a longitudinal direction of the slide fastener 1 (alternatively of fastener stringer 2 or fastener tape 3). The left-right direction is a direction orthogonal to the front-rear direction, and is identical to a width direction of the slide fastener 1 (alternatively of fastener stringer 2 or fastener tape 3). The up-down direction is a direction orthogonal to the front-rear and left-right directions, and is identical to a thickness direction of the fastener tape 3. Certainly, there should be no assumption that the up-down direction matches a vertical direction (gravity direction). That is, the direction-related terms referred in the present specification are to be understood based on the slide fastener 1 and is irrelevant to the vertical direction (gravity direction).

[0043] Configuration of slide fastener 1 would be described with reference to FIGS. 1-3. FIG. 1 is a schematic elevational view of slide fastener 1. FIG. 2 is a schematic diagram showing a condition where a fastener element 4 is attached to a side-edge portion 31 of fastener tape 3. FIG. 3 is a schematic diagram showing a structure of side-edge portion 31 of fastener tape 3, illustration of the fastener elements omitted for a purpose of depicting the structure.

[0044] Typically, the slide fastener 1 is a flexible elongated part that extends in the front-rear direction with a substantially constant width in the left-right direction (the same applies to fastener stringer 2 and fastener tape 3). The slide fastener 1 has a pair of left and right fastener stringers 2 each including a fastener tape 3 and fastener elements 4, and a slider 9 for engaging and disengaging these fastener stringers 2. As the slider 9 moves frontward, the left and right fastener elements 4 attached to the opposed side-edge portions 31 of the left and right fastener stringers 2 are engaged one another, and the left and right fastener stringers 2 are coupled. As the slider 9 moves rearward, the left and right fastener elements 4 are disengaged one another, and the left and right fastener stringers 2 are decoupled. Note that the slide fastener 1 illustrated in the figures may optionally include a front stop 81 and a rear stop 82 but these can be omitted. The slider 9 is made of metal or resin, for example.

[0045] The fastener tape 3 is a woven fabric or knitted fabric or mixture of them, and has a high flexibility. The fastener tape 3 has: a side-edge portion 31 located closer to a central line CL of the slide fastener 1 that matches a movement trajectory of the slider 9; another side-edge portion 32 located away from the central line CL, and a tape main portion 33 located between these side-edge portions 31,32. A width W3 of fastener tape 3 is equal to a total value of a width W31 of the side-edge portion 31, a width W32 of the side-edge portion 32 and a width W33 of the tape main portion 33.

[0046] The fastener elements 4 comprise an array of resin elements attached (via injection molding, for example) to the side-edge portion 31 of the fastener tape 3 (See FIGS. 1 and 2). Alternatively, the fastener elements 4 comprise an array of metal elements swaged to the side-edge portion 31 of the fastener tape 3. Further alternatively, other types of fastener elements (a coil-like element of helically wound resin-made monofilament, for example) may be used.

[0047] The fastener tape 3 has tape main surfaces facing opposite sides in the up-down direction so as to define its thickness, i.e. has a tape top surface 3m and a tape bottom surface 3n (See FIG. 2). Furthermore, the fastener tape 3 has a ground structure 37 structured from plural tape threads (plural warp threads 35 (35a, 35b, 35c, 35d, 35e, 35f . . . ) and at least one weft thread 36, for example). The number of the warp threads 35 may be set appropriately in accordance with a target width W3 of the fastener tape 3. The warp threads 35 are aligned one another as being pulled in the warp direction, and the weft thread 36 extends to meander in the weft direction so as to flow and sink relative to the respective warp threads 35. Each of the warp threads 35 repeats crossing respective units each consisting of two portions of the weft thread aligned one another as being pulled in the weft direction (i.e. the two portions running in parallel) (See FIG. 3). Of course, the ground structure 37 should not be limited to such a woven structure but may be a knitted structure.

[0048] Note that, the tape top surface 3m and the tape bottom surface 3n are formed as two-dimensional uneven surface in accordance with floating and sinking of the weft thread 36. All of the tape threads, which are component threads of the fastener tape 3, are spun from Polyethylene terephthalate (PET) resin and made of the same material, not necessarily limited to this though. Advantageously, this PET resin is a plant-derived material.

[0049] The side-edge portion 31 of the fastener tape 3 to which the fastener elements 4 are attached is provided with a core portion 5. The core portion 5 includes at least one core thread 51 (preferably plural core threads 51) and a (hollow) the tubular portion 52 that surrounds or encloses the at least one core thread 51. The core portion 5 may protrude upward from the tape top surface 3m and protrude downward from the tape bottom surface 3n thereof which are for defining the thickness of the fastener tape 3 (see FIG. 2). The core portion 5 has a portion embedded in the fastener element 4, thereby the attachment strength of the fastener element 4 is improved.

[0050] In some cases, the core portion 5 is a core yarn that is woven into the fastener tape 3. That is, the core portion 5 is produced as a core yarn in advance of weaving the fastener tape 3. The fact that the core portion 5 is a core yarn indicates that the core portion 5 can be taken out from the fastener tape 3 as a core yarn by releasing it from the weft thread 36 even when the core yarn has been woven into the fastener tape 3. The use of the core yarn as the core portion 5 may facilitate more precise control of the degree of contact between the core thread 51 and the tubular portion 52 or the degree of static friction therebetween.

[0051] In some cases, plural (two in the example of FIGS. 2 and 3) core portions 5 are paired and arranged in the side-edge portion 31. For example, a top core portion 5m and a bottom core portion 5n are used as two core portions 5, and they are paired in the up-down direction and protrude on the both top and bottom sides. Each of the top core portion 5m and the bottom core portion 5n is bound by the weft thread 36 at a position between adjacent warp threads 35, but a method of securing the core portion in the fastener tape 3 should not be limited to this manner.

[0052] In the present embodiment, at least one core thread 51 includes a crimp able thread which is crimped in accordance with a difference in thermal shrinkage ratio between different polymer materials. Generally, threads with lower elongation value in the warp direction are used as core threads. Contrary to this technical standard, the present inventor has newly discovered that the Plus-biased state of fastener stringer may be more easily imparted to the fastener stringer 2 by employing the crimp able thread(s) as the core thread(s) 51. Although the precise mechanism of this has been not revealed yet, one rationale is assumed that a degree of crimp of the crammable thread (the core thread 51), which has been crimped by thermal setting, can be regulated e.g. by stretching the fastener tape 3. Moreover, another rationale is assumed that the static friction between the crimpable thread (the core thread 51) and the tubular portion 52 is increased so that the degree of crimp of the crimpable threads is not easily changed unless a force were applied thereto such as by stretching the fastener tape 3.

[0053] If a crimpable thread is employed as a core thread and thermally set, the core thread would crimp in a degree in accordance with (e.g. in proportion to) a difference in thermal shrinkage ratio between different polymer materials of the core thread. This crimp of the core thread 51 imparts to the fastener stringer 2 the Plus-biased state of fastener stringer, and simultaneously increases the static friction between the core thread 51 and the tubular portion 52 (because of increased degree of crimp of the crimpable thread (the core thread 51)). There may be a situation where a crimpable thread is used as the core thread 51, causing excessively-Plus-biased state of the fastener stringer; however, this may be adjustable through a process of stretching the fastener stringer 2 along its longitudinal direction. Also, the fastener stringer 2 may maintain its appropriate-biased state of fastener stringer after the adjustment, owing to the increased static friction between the core thread 51 and the tubular portion 52.

[0054] It should be noted that the process of stretching the fastener tape 3 would be unnecessary depending on a degree of crimp of the crimpable thread caused by the thermal setting. Moreover, the process of stretching the fastener tape 3 after the thermal setting may be performed at any timing and in any degree. This may be performed in a sewing process where the fastener tape 3 of the fastener stringer 2 is sewn to a fabric of clothes after the slide fastener 1 is sold.

[0055] Again, a crimpable thread is employed as a core thread, allowing the fastener stringer 2 to more easily maintain its current Plus-biased state of fastener stringer based on the static friction between the core thread 51 and the tubular portion 52 (unless external force applied). In a time window from a time point of manufacturing or selling of slide fastener 1 to a time point of sewing it at a sewing factory, it may be suppressed that the fastener stringer 2 shifts from the Plus-biased state of fastener stringer to Zero-biased state of fastener stringer.

[0056] When the fastener tape 3 of the fastener stringer 2 is sewn to a fabric of clothes or the like, the contraction is caused in the fastener tape 3 by and along stitches of a sewing thread shown by alternate long and short dashed lines in FIG. 5. However, owing to the Plus-biased condition of fastener stringer, the side-edge portion 31 of the fastener tape 3 shifts from a curved state like a recess and an arch (FIG. 4) to a linearly extending state (FIG. 5). Accordingly, the pitches of the fastener elements 4 in the front-rear direction would be within a tolerance range. Note that, the state of the fastener stringer 2 depicted in FIG. 5 may be referred to as a zero-biased state of fastener stringer.

[0057] It has been confirmed that use of other types of threads (e.g. False-twisted thread) having a similar thermal shrinkage ratio as that of the crimpable thread did not suitably impart to the fastener stringer 2 the Plus-biased state of fastener stringer (compared with that of the instant disclosure). This proves that the fastener stringer 2 is suitably controlled into the Plus-biased state of fastener stringer based on not only the shortening due to the thermal shrinking but also the crimp of the crimpable thread. Illustration of Minus-biased state of fastener stringer is omitted, but this means a state where the fastener stringer 2 is curved on the opposite side of one shown in FIG. 4.

[0058] The core portion 5 may include total N (N indicates a natural number of 2 or more) core threads 51 as the at least one core thread 51. Each of the total N core threads 51 may be a crimpable thread. The total N core threads 51 may be pulled and aligned in the warp direction to configure a doubling (associated threads), or may be twisted together along the warp direction to configure a strand of threads. In some cases, the core portion 5 includes crimpable thread(s) only as the core thread(s) 51 but in other cases, the core threads 51 include a non-crimpable thread (e.g. textured thread). Note that, crimpable thread stated in the present specification indicates a thread that is crimped in accordance with a difference in thermal shrinkage ratio between different polymer materials (that is, it does not indicate a crimp of False-twisted thread). Typically, a False-twisted thread is spun from a single polymer material and consists of the single polymer material, and has a crimp characteristic in accordance with following processes; however, it does not crimp in accordance with a difference in thermal shrinkage ratio between different polymer materials. In cases where non-crimpable thread(s) is included, a number of crimpable threads is preferably greater than a number of non-crimpable threads.

[0059] In some cases, the tubular portion 52 includes a knitted structure of the plural skin threads 52a-52d which are knitted (e.g. see FIG. 6). Each of the skin thread 52a-52d is typically a non-crimpable thread and made through spinning of single polymer material. Configuring the tubular portion 52 as the knitted structure allows the contact between the core threads 51 and the tubular portion 52 to be maintained regardless of how the core threads 51 are crimped, and selecting the skin threads having an appropriate thermal shrinkage ratio allows the core threads to be tightened by the skin threads.

[0060] It should be noted that FIG. 6 is a schematic drawing drawn for a purpose of illustration. In FIG. 6, an imaginary cylindrical space R51 indicates a space where the plural core threads 51 are arranged. Specific methods for configuring the tubular portion 52 as a knitted structure are well-known for a skilled person in the art. For example, four latching needles are arranged in a circumferential direction at an equal interval of 90, and the skin thread is fed, so as to trace a numeral letter of 8, to the latching needles which are opposing at 180. Needle loops are formed at locations corresponding to the latching needles. As depicted in FIG. 6, the entanglement between the skin threads having a phase difference of 180 in the circumferential direction continues, thereby the knitted structure is configured.

[0061] The crimpable thread used as the core thread 51 is a composite thread having filaments 71, 72 of at least two types of polymer materials having different thermal shrinkage ratios; in other words, the crimpable thread may be a composite thread 7 made through spinning together at least two types of polymer materials having different thermal shrinkage ratios (e.g. see FIG. 7). In FIG. 7, the polymer material of the filament 71 has a first thermal shrinkage ratio, and the polymer material of the filament 72 has a second thermal shrinkage ratio which is different from the first thermal shrinkage ratio. The polymer material of the filament 71 is PET (polyethylene terephthalate), for example. The polymer material of the filament 72 is PTT (polytrimethylene terephthalate), for example. It should not be limited to a specific way where the filaments 71, 72 are adjoined and coupled, the filaments 71, 72 may be coupled such that one thread is encapsulated by the other thread. It is possible to spin a crimpable thread from three types of polymer materials which differ in the thermal shrinkage ratio.

[0062] The degree of crimp of the crimpable thread changes between before and after the crimpable thread is crimped. FIG. 8 shows the crimpable core thread before the thermal setting, and FIG. 9 shows the crimpable core thread after the thermal setting. As clearly understandable from the comparison of the two figures, the thermal setting results in increased degree of crimp per a unit length (e.g. increased number of helical units per a unit length). Note that, the core threads 51, each being the crimpable thread, may be bundled to allow one to handle them as one yarn depicted by dotted line in FIGS. 8 and 9.

[0063] The three-dimensional shape of the crimpable thread should not be limited to a regular helical shape as depicted in FIG. 8 but may be a random helical shape where the density of helical units changes along the length direction of the thread.

[0064] Moreover, the crimpable thread may be shaped like a wave as depicted in FIG. 10 unlike the helix. One crimpable thread may be helical in one given zone and may be wave-like in another zone along its length direction. That is, envisioned is that the crimpable thread has a shape having a random pattern of helical shape and wave-like shape.

[0065] The degree of crimp of the crimpable thread may be expressed by a number of protrusions in accordance with helix or wave per a unit length (1 cm). In a case where the crimpable thread is crimped helically, one protrusion corresponds to one winding of the helix (see a frame illustrated by alternate long and short dashed lines in FIGS. 8 and 9). In a case where the crimpable thread is crimped in the wave, one protrusion corresponds to one unit of wave (see a frame illustrated by alternate long and short dashed lines in FIG. 10).

[0066] The crimpable thread may be introduced only to the core thread 51 of the core portion 5. That is, every thread in the fastener tape 3 other than the core thread(s) 51 is a non-crimpable thread, and is made of single polymer material through spinning of the single polymer material. In other words, except for the core thread(s) 51, the faster tape 3 does not include a crimpable thread that is crimped in accordance with a difference in thermal shrinkage ratio between different polymer materials. In this case, the degree of crimp may be easily adjusted based on adjustment of the number of the crimpable core thread 51, i.e. easily avoided is that the extent of crimp becomes too high or too low. By way of precaution, in a case where only the core thread 51 is a crimpable thread, the side-edge portion 32 and the tape main portion 33 do not include any crimpable thread that is crimped in accordance with a difference in thermal shrinkage ratio between different polymer materials. Except for the core thread 51, the side-edge portion 31 does not include a crimpable thread that is crimped in accordance with a difference in thermal shrinkage ratio between different polymer materials. In some cases, the side-edge portion 32 is configured from warp threads that are equal in thickness and density to the warp threads of the tape main portion 33, and does not include a thread (so-called selvage thread) that is thicker than the warp threads of the tape main portion 33. In a case where the selvage threads are omitted, light-weight and cost-down of the fastener stringer may be facilitated.

[0067] With reference to FIGS. 11 and 12, discussion follows on a load test conducted for a bundle 6 of 3 crimpable threads after the thermal setting. FIG. 11 is a schematic view showing a procedure of load test. FIG. 12 is a graph showing a result of load test. As depicted in FIG. 11, the bundle 6 is fixed at the top end point P1 in its test zone and linearly extends vertically downward, and a weight 61 is attached to the bottom end point P2 in the test zone. An amount of displacement of the midpoint P3 located at the center between the top end point P1 and the bottom end point P2 is monitored in timings before and after the bundle 6 is pulled by the weight 61 toward the ground.

[0068] The broken line L1 in FIG. 12 shows a load curve where the non-crimpable threads are used as the core threads. The alternate long and short dashed lines L2 show a load curve where crimpable threads, having relatively smaller thermal shrinkage ratio, are used as the core threads. The solid line L3 shows a load curve where crimpable threads, having relatively larger thermal shrinkage ratio, are used as the core threads. The use of the crimpable threads as the core threads allows the faster tape 3 to stretch more greatly as seen in L2 and L3. This indicates easier adjustment in the length of the of the fastener tape 3 after the thermal setting, and could be a remedy for excessive crimp of the core thread 51.

[0069] Preferably, a crimpable thread is used which has an elongation value (elongation ratio) of 7% or more. For example, a crimpable thread having an elongation value of 7%-10% is used preferably. The elongation value of the crimpable thread would be evaluated by the load test shown in FIG. 11, and in particular be calculated as an elongation value (((elongated length-original length)/original length)*100) in a condition where a weight of a given mass is attached to a bundle of three crimpable threads.

[0070] A method of manufacturing the fastener tape 3 would be described with reference to FIG. 13. Firstly, the faster tape 3 to which the core portion 5 is attached is configured (S1). In detail, the fastener tape 3 with the core portion 5 which is provided in the side-edge portion 31 is configured. For this purpose, automatic loom or knitting machine may be used. In a case where the core portion 5 is a core yarn that is woven into the fastener tape 3, the step S1 may include configuring the core portion 5 as the core yarn, and weaving the fastener tape 3 so as to include the core portion 5. The step of configuring the core portion 5 as a core yarn may include pulling and aligning plural core threads 51 and configuring a tubular portion 52 around the bundle of the plural core threads 51 (See FIG. 6). The tubular portion 52 is preferably configured by knitting as a knitted structure. In the step of weaving the fastener tape 3 so as to include the core portion 5, the core portion 5 is retained by the weft thread and woven into the fastener tape 3. As illustrated in FIGS. 2 and 3, a pair of top and bottom core portions 5 (core yarns) may be woven into the fastener tape 3.

[0071] Next, the fastener tape 3 is thermally set (i.e. heated) to allow the crimpable thread to be crimped (S2). The temperature of thermal setting depends on the material of the crimpable thread, and the heat source such as a heater may be set at a temperature ranging between 160 C. and 200 C., for example. The side-edge portion 31 of the fastener tape 3 and the heat source are placed to face one another in the proximity, and thus heating the side-edge portion 31 of the fastener tape 3. Different polymer materials thermally shrink in different extents in the crimpable thread used as the core thread 51. As a result, the crimpable thread is crimped and the core portion 5 is shortened in length, imparting to the fastener stringer the Plus-biased state. The heater may be located aside a transferring passage for the fastener tape 3. The heater may be an electric heater that generates heat based on current flow for example, but other types of heaters can be employed.

[0072] Next, first post-processing is conducted for the fastener tape 3 (S3). The first post-processing may include dyeing the fastener tape 3. The fastener tape 3 may be transferred, via plural rollers (e.g. rollers 101, 102 depicted in FIG. 14), into a tank storing a staining solution or toward a discharging port of an ink-jet printer for dyeing. The fastener tape 3 runs in a predefined passage defined by plural rollers while a tension is applied thereto along its longitudinal direction. Therefore, the degree of crimp of the crimpable thread is reduced, lowing the degree of the Plus-biased state of fastener stringer.

[0073] Next, second post-processing is conducted to the fastener tape 3 (S4). The second post-processing may include drying the fastener tape 3. In the step of drying, the fastener tape is reheated. For this purpose, a heater may be used similarly to the above-described one. In a case where dyeing is conducted in the first post-processing, the fastener tape 3 to or into which the dyeing liquid is attached or penetrates would be dried. In either case, the degree of the crimp of the crimpable thread used as the core thread 51 would be enhanced due to the thermal shrinking.

[0074] After the step S2, at least one step for lowing the degree of the crimp of the crimpable thread and at least one step for increasing the degree of the crimp of the crimpable thread may be conducted simultaneously or in this order, thus facilitated is that an appropriate Plus-biased state is imparted to the fastener tape 3. The former one of the first and second post-processings (S3, S4) includes a process for lowering the degree of the crimp of the crimpable thread, and the latter one includes a process for increasing the degree of crimp of the crimpable thread. This allows that, even if the Plus-biased state of the fastener stringer 2 becomes too excessive during the thermal setting (S2), the fastener stringer 2 may be smoothly shifted into an appropriate-biased state through the first and second post-processings.

[0075] The steps S3, S4 should not be limited to the dyeing and drying. Also when the fastener tape 3 is placed in a cavity of mold for injection molding, a tension is applied to the fastener tape 3 in its longitudinal direction. Moreover, the fastener tape 3 is heated in accordance with heat received from molten resin or mold during the injection molding. In this case, the first post-processing (stretching of the fastener tape 3 in the mold cavity) and the second post-processing (thermal shrinking of crimpable thread in accordance with heat transmitted from the mold) are simultaneously conducted.

[0076] As illustrated in FIG. 15, a tubular portion 52 as a double weave structure 38 may be formed in a part of the ground structure 37 of the fastener tape 3, and the core thread 51 may be introduced into the tubular portion 52. The similar effects as noted above may be obtained in this case either.

[0077] As shown in FIG. 16, it is possible to employ a coil element as the fastener elements 4. The coil element is sewn onto the tape main surface (e.g. the tape bottom surface) of the fastener tape 3. On the opposite side, the core portion 5 is provided on the fastener tape 3. In particular, one of the core portions in FIGS. 2 and 3 (e.g. the upper core portion 5m only) is woven into the fastener tape 3 (the bottom core portion 5n in FIGS. 2 and 3 omitted). Other embodiments are also envisioned.

[0078] Based on the above-described teachings, those skilled in the art may make various changes to each embodiment. 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

[0079] 1: Slide fastener [0080] 2: Fastener stringer [0081] 3: Fastener tape [0082] 4: Fastener element [0083] 5: Core portion [0084] 7: Composite thread [0085] 9: Slider [0086] 31: Side-edge portion [0087] 32: Side-edge portion [0088] 33: Tape main portion [0089] 35: Warp thread [0090] 36: Weft thread [0091] 37: Ground structure [0092] 51: Core thread [0093] 52: Tubular portion [0094] 52a-52d: Skin thread