Fastener tape and method for manufacturing same, and fastener stringer

Abstract

A core section (5) is provided to a side edge section (31) of a fastener tape (3) to which a fastener element (4) is attached. The core section (5) includes at least one core thread (51) and a tubular section (52) that surrounds the at least one core thread (51). The at least one core thread (51) includes a crimped thread that is crimped due to a difference between thermal shrinkage rates of different polymeric materials.

Description

Fastener tape, manufacturing method thereof, and fastener stringer

[0001] The present disclosure relates to a fastener tape, a method for manufacturing the same, and a fastener stringer.

[0002] When the fastener tape of a fastener stringer is sewn to a fabric such as clothing with a sewing thread, the fastener tape may ripple, resulting in uneven spacing between the fastener elements and poor engagement of the fastener elements. To avoid or suppress this problem, it is desirable to set the fastener stringer in a positive stringer bias state before sewing it to the fabric. In a fastener stringer with a positive stringer bias, the fastener tape has an arch shape in which the side edge to which the fastener elements are attached is curved concavely and the opposite side edge is curved convexly (see Figure 4 of the present application). Note that, for convenience of explanation, the degree of the arch shape of the fastener tape in Figure 4 of the present application is exaggerated compared to the actual state. Furthermore, the fastener tape is observed by viewing its main surface (e.g., its upper surface or lower surface) from the front.

[0003] In Patent Document 1, a yarn having a higher elongation recovery rate than other warp yarns is arranged adjacent to the outer side of the core cord. Even if the fastener tape is stretched when fastener elements are attached, the side edge portion is likely to return to its original length, and a positive stringer bias state is maintained. Patent Document 2 discloses that the length of the warp yarns at one side edge portion of the fastener tape is made relatively long to form an arch shape of the fastener tape (see Figure 4 of the same document).

[0004] Although unrelated to the above-mentioned problem, Patent Document 3 discloses weaving a knitted cord into the hollow woven portion of a fastener tape and integrally joining the two by thermal shrinkage of the hollow woven portion. In this document, the knitted cord is formed by knitting an outer circumferential knitted layer consisting of multiple warp knitted yarns around a core yarn. Examples of the core yarn include false twisted yarn and spun yarn, and it is described that it is preferable to reduce the elongation in the warp direction (page 6, lines 7-10). Patent Document 4 discloses using a latent crimp-developing polyester fiber as the weft yarn.

[0005] JP 2004-229729 A Chinese Utility Model No. 212590695 Specification Japanese Utility Model Laid-Open No. 55-422 A Japanese Patent Laid-Open No. 2006-175129 A

[0006] The inventors of the present application have discovered a new problem of how to bring the fastener stringer into a state where the stringer bias is positive, using an approach different from conventional approaches.

[0007] A fastener tape according to one embodiment of the present disclosure has a core portion provided at a side edge portion of the fastener tape to which a fastener element is attached, the core portion including at least one core thread and a tubular portion surrounding the at least one core thread, and the at least one core thread including a crimpable thread that is crimped in accordance with the difference in thermal shrinkage rate of different polymeric materials.

[0008] In some embodiments, the core portion includes a total of N (N is a natural number of 2 or more) core yarns as the at least one core yarn, and each of the total N core yarns is the crimpable yarn.

[0009] In some embodiments, the crimpable yarn is a composite yarn formed by bonding together threads made of at least two polymeric materials with different heat shrinkage rates.

[0010] In some embodiments, the crimpable yarn is a composite yarn in which at least two polymeric materials with different heat shrinkage rates are spun together.

[0011] In some embodiments, the crimpable yarn is crimped in a spiral and / or wavy manner.

[0012] In some embodiments, the core portion is a core cord woven into the fastener tape.

[0013] In some embodiments, the tubular portion includes a knitted structure in which a plurality of skin threads are knitted.

[0014] In some embodiments, except for the at least one core yarn, the fabric does not include any crimpable yarn that crimps in response to the difference in heat shrinkage rate of different polymeric materials.

[0015] A fastener stringer according to another aspect of the present disclosure includes any of the fastener tapes described above and fastener elements attached to the side edge portions of the fastener tape.

[0016] A method for manufacturing a fastener tape according to another aspect of the present disclosure includes a step of forming a fastener tape having a core portion provided at one side edge portion, the core portion including at least one core thread and a tubular portion surrounding the at least one core thread, the at least one core thread including a crimpable thread that is crimped in accordance with the difference in thermal shrinkage rate of different polymeric materials, and a step of heating the fastener tape so that the crimpable thread is crimped.

[0017] In some embodiments, the method further comprises, after the step of heating the fastener tape, stretching the fastener tape along its longitudinal direction so as to reduce the degree of crimping of the crimpable yarn.

[0018] In some embodiments, the fastener tape is stretched while running along a running path defined by a plurality of rollers while tension is applied in the longitudinal direction of the fastener tape.

[0019] In some embodiments, the method further comprises, after the step of stretching the fastener tape, the step of reheating the fastener tape to increase the degree of crimp of the crimpable yarn.

[0020] In some embodiments, the manufacturing method further includes a step of dyeing the fastener tape, and the step of reheating the fastener tape is carried out during the process of drying the fastener tape by heating.

[0021] In some embodiments, after the step of heating the fastener tape, at least one step of reducing the crimp level of the crimpable yarn and at least one step of increasing the crimp level of the crimpable yarn are performed simultaneously or in that order.

[0022] According to one aspect of the present disclosure, it is possible to promote a positive stringer bias state for a fastener stringer using a method different from conventional methods.

[0023] 8 is a schematic front view of a slide fastener according to one embodiment of the present disclosure. FIG. 9 is a schematic view showing a state in which fastener elements are attached to side edge portions of a fastener tape. FIG. 10 is a schematic view showing the structure of side edge portions of a fastener tape, with the fastener elements not shown. FIG. 11 is a schematic front view of a fastener stringer in a positive stringer bias state. FIG. 12 is a schematic front view of a fastener stringer showing a state in which the stringer bias has changed from a positive state to a zero state due to shrinkage associated with sewing. FIG. 13 is a schematic view showing that the tubular portion of the core is formed with a knitted structure. FIG. 14 is an enlarged schematic view of one core yarn. FIG. 15 is a schematic view showing two crimpable core yarns before heat setting. FIG. 16 is a schematic view showing two crimpable core yarns after heat setting, with the degree of crimp per unit distance (e.g., the number of spirals per unit distance) increased compared to FIG. 10. FIG. 11 is a schematic view showing a crimpable yarn that crimps in a wavy pattern. FIG. 12 is a schematic view showing the procedure for conducting a load test. FIG. 13 is a graph showing the results of a load test. FIG. 14 is a schematic flow chart showing a method for manufacturing a fastener tape. 1 is a schematic diagram showing a state in which a fastener tape runs on a running path determined by rollers, and FIG. 2 is a schematic diagram showing another embodiment in which a crimpable yarn is enclosed as a core yarn in a hollow woven portion of a side edge portion of the fastener tape, and FIG. 3 is a schematic diagram showing another example in which a core portion is woven into the fastener tape on the opposite side of the coil-shaped element.

[0024] Various embodiments and features will be described below with reference to the drawings. Those skilled in the art will be able to combine the various embodiments and / or features without excessive explanation and will also be able to understand the synergistic effects of such combinations. Duplicate descriptions between embodiments will generally be omitted. The reference drawings are primarily intended to describe the invention and are simplified for ease of illustration. Each feature is not only applicable to the fastener tape, the manufacturing method thereof, and the fastener stringer disclosed in this specification, but is also understood as a universal feature applicable to various other fastener tapes, manufacturing methods thereof, and fastener stringers not disclosed in this specification.

[0025] In this specification, terms indicating directions such as the front-rear direction, the left-right direction, and the up-down direction are referred to. The front-rear direction corresponds to the movement direction of the slider 9 for opening and closing the slide fastener 1, and corresponds to the longitudinal direction of the slide fastener 1 (or the fastener stringer 2 or the fastener tape 3). The left-right direction is a direction perpendicular to the front-rear direction and corresponds to the width direction of the slide fastener 1 (or the fastener stringer 2 or the fastener tape 3). The up-down direction is a direction perpendicular to the front-rear and left-right directions and corresponds to the thickness direction of the fastener tape 3. Of course, the up-down direction does not have to correspond to the vertical direction (the direction of gravity). In other words, the terms indicating directions referred to in this specification are understood based on the slide fastener 1 and are unrelated to the vertical direction (the direction of gravity).

[0026] The configuration of the slide fastener 1 will be described with reference to Figures 1 to 3. Figure 1 is a schematic front view of the slide fastener 1. Figure 2 is a schematic diagram showing a state in which fastener elements 4 are attached to a side edge portion 31 of a fastener tape 3. Figure 3 is a schematic diagram showing the structure of the side edge portion 31 of the fastener tape 3, and the fastener elements are omitted to illustrate the structure.

[0027] The slide fastener 1 is typically a flexible, elongated member that extends longitudinally in the front-to-rear direction with a substantially constant left-to-right width (the same applies to the fastener stringer 2 and fastener tape 3). The slide fastener 1 includes a pair of left and right fastener stringers 2, each including a fastener tape 3 and a fastener element 4, and a slider 9 for engaging and disengaging these fastener stringers 2. When the slider 9 advances, the left and right fastener elements 4 attached to the opposing side edges 31 of the left and right fastener stringers 2 interlock with each other, engaging the left and right fastener stringers 2. When the slider 9 moves backward, the left and right fastener elements 4 are disengaged, disengaging the left and right fastener stringers 2. The illustrated slide fastener 1 includes an upper stop 81 and a lower stop 82 as options, but both can be omitted. The slider 9 is made of, for example, metal or resin.

[0028] The fastener tape 3 is a woven fabric, a knitted fabric, or a mixture thereof, and has high flexibility. The fastener tape 3 has a side edge 31 close to the center line CL of the slide fastener 1 that coincides with the movement trajectory of the slider 9, another side edge 32 away from the center line CL, and a tape main portion 33 provided between these side edges 31, 32. The width W3 of the fastener tape 3 is equal to the sum of the width W31 of the side edge 31, the width W32 of the side edge 32, and the width W33 of the tape main portion 33.

[0029] The fastener elements 4 may comprise an array of resin elements affixed (e.g., via injection molding) to the side edge 31 of the fastener tape 3 (see FIGS. 1 and 2). Alternatively, the fastener elements 4 may comprise an array of metal elements crimped to the side edge 31 of the fastener tape 3. Alternatively, other types of fastener elements (e.g., coil elements formed by spirally winding a resin monofilament) may be used.

[0030] The fastener tape 3 has two tape main surfaces, namely, an upper tape surface 3m and a lower tape surface 3n, facing opposite sides in the vertical direction to define its thickness (see FIG. 2). Furthermore, the fastener tape 3 has a ground structure 37 constructed from a large number of tape threads (e.g., multiple warp threads 35 (35a, 35b, 35c, 35d, 35e, 35f, ...) and at least one weft thread 36). The number of warp threads 35 is appropriately set according to the target tape width W3 of the fastener tape 3. The warp threads 35 are aligned in the warp direction, and the weft threads 36 extend in a meandering weft direction, rising and sinking relative to the warp threads 35. Each warp thread 35 repeatedly crosses over two weft threads aligned in the weft direction (i.e., running parallel in the weft direction) as a unit (see FIG. 3). Of course, the ground structure 37 is not limited to a woven structure, and may be a knitted structure.

[0031] Incidentally, two-dimensional unevenness corresponding to the ups and downs of the weft yarns 36 is formed on the upper tape surface 3m and the lower tape surface 3n. Although not necessarily limited to this, all of the tape yarns constituting the fastener tape 3 are spun from polyethylene terephthalate (PET) resin and made of the same material. Advantageously, this PET resin is a plant-derived raw material.

[0032] A core 5 is provided on the side edge 31 of the fastener tape 3 to which the fastener elements 4 are attached. The core 5 includes at least one (preferably multiple) core thread 51 and a (hollow) tubular portion 52 that surrounds or contains the at least one core thread 51. The core 5 can protrude upward from the tape upper surface 3m that defines the thickness of the fastener tape 3 and can protrude downward from the tape lower surface 3n (see FIG. 2). The core 5 has a portion embedded in the fastener element 4, which increases the attachment strength of the fastener element 4.

[0033] In some cases, the core 5 is a core string woven into the fastener tape 3. That is, the core 5 is manufactured as a core string in advance before the fastener tape 3 is woven. The fact that the core 5 is a core string means that even after the core string has been woven into the fastener tape 3, it can be taken out as a core string from the fastener tape 3 by releasing the restraint by the weft yarn 36. Using a core string as the core 5 facilitates more precise control of the degree of adhesion between the core yarn 51 and the tubular portion 52, or the degree of static friction that may occur between them.

[0034] In some cases, a plurality of cores 5 (two in the example of Figs. 2 and 3) are combined and provided at the side edge 31. For example, an upper core 5m and a lower core 5n are used as the two cores 5, and these are combined in the vertical direction to protrude on both the top and bottom sides. Each of the upper core 5m and the lower core 5n is constrained by the weft threads 36 at a position between the adjacent warp threads 35, but the method of fixing the cores in the fastener tape 3 is not limited to this embodiment.

[0035] In this embodiment, at least one core yarn 51 includes a crimpable yarn that is crimped in accordance with the difference in the thermal shrinkage rate of different polymeric materials. Generally, a yarn with small warp elongation is used as a core yarn. The inventors of the present application discovered that, contrary to conventional wisdom, using a crimpable yarn as the core yarn 51 makes it easier to adjust the stringer bias of the fastener stringer 2 to a positive state. While the exact mechanism behind this is not yet clear, one possible reason is that the degree of crimp of the crimpable yarn (core yarn 51) can be adjusted by, for example, stretching the fastener tape 3 after the crimpable yarn (core yarn 51) is crimped by heat setting. Another possible reason is that static friction between the crimpable yarn (core yarn 51) and the tubular portion 52 is large, making it difficult to change the degree of crimp of the crimpable yarn unless a force, such as stretching the fastener tape 3, is applied.

[0036] When a crimpable yarn is used as the core yarn and heat-set, the core yarn crimps to a degree corresponding to (e.g., proportional to) the difference in the thermal shrinkage rates of the different polymeric materials. This crimping of the core yarn 51 causes the fastener stringer 2 to have a positive stringer bias, and at the same time, the static friction between the core yarn 51 and the tubular portion 52 increases (because the degree of crimping of the crimpable yarn (core yarn 51) increases). While using a crimpable yarn as the core yarn 51 may result in an excessively positive stringer bias, this can be adjusted by stretching the fastener stringer 2 along its longitudinal direction. Furthermore, due to the increased static friction between the core yarn 51 and the tubular portion 52, the fastener stringer 2 can maintain an appropriate stringer bias after the adjustment.

[0037] It should be noted that depending on the degree of crimping of the crimpable yarn by heat setting, the step of stretching the fastener tape 3 may not be necessary. Also, the step of stretching the fastener tape 3 after heat setting can be carried out at any timing and to any extent. It can also be carried out at the sewing stage when the fastener tape 3 of the fastener stringer 2 is sewn to the fabric of a garment after the slide fastener 1 is sold.

[0038] To reiterate, by using a crimped yarn as the core yarn 51, the fastener stringer 2 can easily maintain its current positive stringer bias (unless an external force is applied) based on static friction between the core yarn 51 and the tubular portion 52. It is also possible to prevent the fastener stringer 2 from changing from a positive stringer bias to a zero stringer bias during the period from the time of manufacture or sale of the slide fastener 1 to the time of sewing at a sewing factory.

[0039] When the fastener tape 3 of the fastener stringer 2 is sewn to the fabric of a garment or the like, the fastener tape 3 contracts along the stitching of the sewing thread shown by the dashed line in Figure 5, but because the stringer bias is in a positive state, the side edge 31 of the fastener tape 3 changes from a concave, arc-shaped curve (Figure 4) to a linear extension (Figure 5). Thus, the pitch of the fastener elements 4 in the front-to-rear direction falls within the allowable tolerance range. The state of the fastener stringer 2 shown in Figure 5 can also be called a state in which the stringer bias is zero.

[0040] It has also been confirmed that even when other types of yarn (e.g., false-twist textured yarn) that exhibit a similar heat shrinkage rate to the crimpable yarn are used, the positive stringer bias of the fastener stringer 2 cannot be controlled as well (compared to the present disclosure). This confirms that the positive stringer bias of the fastener stringer 2 can be controlled as well depending not only on the shortening due to heat shrinkage but also on the crimp exerted by the crimpable yarn. Although the illustration of a negative stringer bias is omitted, this refers to a state in which the fastener stringer 2 is warped in the opposite direction to that shown in Figure 4.

[0041] The core 5 may include a total of N (N is a natural number equal to or greater than 1) core yarns 51 as at least one core yarn 51. Each of the N core yarns 51 may be a crimpable yarn. The N core yarns 51 may be doubled yarns drawn together in the warp direction, or twisted yarns twisted together in the warp direction. In some cases, the core 5 includes only crimpable yarns as core yarns 51, while in other cases, the core yarns 51 include non-crimpable yarns (e.g., textured yarns). Note that the term "crimpable yarn" as used herein refers to a yarn that crimps in response to the difference in the heat shrinkage rates of different polymeric materials (i.e., it does not refer to the crimpability exhibited by false twist textured yarns). False twist textured yarns are typically spun from a single polymeric material and comprise a single polymeric material, and have crimpability in response to subsequent processing, but do not crimp in response to the difference in the heat shrinkage rates of different polymeric materials. When non-crimpable yarns are included, the number of crimpable yarns is preferably greater than the number of non-crimpable yarns.

[0042] In some cases, the tubular portion 52 includes a knitted structure in which multiple sheath yarns 52a-52d are knitted (see, for example, FIG. 6). Each sheath yarn 52a-52d is typically a non-crimpable yarn spun from a single polymer material. By knitting the tubular portion 52 into a knitted structure, contact between the core yarn 51 and the tubular portion 52 can be ensured regardless of how the core yarn 51 crimps. Furthermore, by selecting sheath yarns with an appropriate heat shrinkage rate, it is possible to tighten the core yarns with the sheath yarns.

[0043] It should be noted that Figure 6 is a simplified diagram created for the purpose of explanation. In Figure 6, a cylindrical virtual space R51 indicates a space in which multiple core yarns 51 are arranged. Specific methods for forming a knitted structure in the tubular portion 52 are known to those skilled in the art. For example, four latch needles are arranged in the circumferential direction at equal intervals of 90°, and sheath yarns are fed in a figure-eight pattern to the latch needles that face each other at an angle of 180°. Needle loops are formed at positions corresponding to the latch needles. As shown in Figure 6, sheath yarns with a phase difference of 180° in the circumferential direction are continuously entangled to form a knitted structure.

[0044] The crimpable yarn used as the core yarn 51 is a composite yarn formed by bonding together threads 71 ​​and 72 made of at least two polymeric materials with different heat shrinkage rates. In other words, it can be a composite yarn 7 formed by spun together at least two polymeric materials with different heat shrinkage rates (see, for example, FIG. 7 ). In FIG. 7 , the polymeric material of thread 71 has a first heat shrinkage rate, and the polymeric material of thread 72 has a second heat shrinkage rate different from the first heat shrinkage rate. The polymeric material of thread 71 is, for example, polyethylene terephthalate (PET). The polymeric material of thread 72 is, for example, polytrimethylene terephthalate (PTT). The threads 71 ​​and 72 are not limited to being bonded adjacent to each other, but may also be bonded so that one is enclosed within the other. It is also possible to spin a crimpable yarn from three polymeric materials with different heat shrinkage rates.

[0045] The degree of crimp of a crimpable yarn changes before and after crimping. Figure 8 shows a crimpable core yarn before heat setting, and Figure 9 shows a crimpable core yarn after heat setting. As can be seen from comparing the two figures, heat setting increases the degree of crimp per unit distance (e.g., the number of spirals per unit distance). Furthermore, by bundling multiple core yarns 51, each of which is a crimpable yarn, they can be treated as a single doubled yarn, as shown by the dotted lines in Figures 8 and 9.

[0046] The three-dimensional shape of a crimpable yarn is not limited to a regular helical shape as shown in Figure 8, but may be a random helical shape in which the helical density varies along the yarn length. Also, a crimpable yarn may be wavy rather than helical, as shown in Figure 10. It is also conceivable that a single crimpable yarn may have a shape in which some sections along its length are helical and other sections are wavy, i.e., a shape in which helical and wavy shapes appear randomly.

[0047] The degree of crimping of a crimpable yarn can be expressed by the number of spiral or wave convexities contained per unit distance (1 cm). When a crimpable yarn is crimped spirally, one convexity corresponds to one turn of the spiral (see the dashed-dotted box in Figures 8 and 9). When a crimpable yarn is crimped wave-like, one convexity corresponds to one wave (see the dashed-dotted box in Figure 10).

[0048] A crimpable yarn may be introduced only in the core yarn 51 of the core portion 5. That is, all other yarns in the fastener tape 3, except for the core yarn 51, are non-crimpable yarns spun from a single polymeric material and made of a single polymeric material. In other words, the fastener tape 3 does not contain any crimpable yarns that crimp in response to the difference in the thermal shrinkage rates of different polymeric materials, except for the core yarn 51. In this case, the degree of crimping can be easily adjusted by adjusting the number of crimpable core yarns 51, i.e., excessive or insufficient crimping can be easily avoided. Just to be clear, if only the core yarn 51 is a crimpable yarn, the side edge portions 32 and the tape main portion 33 do not contain any crimpable yarns that crimp in response to the difference in the thermal shrinkage rates of different polymeric materials. The side edge portions 31, except for the core yarn 51, do not contain any crimpable yarns that crimp in response to the difference in the thermal shrinkage rates of different polymeric materials. In some cases, the side edge portion 32 is made up of warp threads of the same thickness and density as the warp threads of the tape main portion 33, and does not include threads (commonly called selvage threads) that are thicker than the warp threads of the tape main portion 33. Omitting the selvage threads promotes weight reduction and cost reduction of the fastener stringer.

[0049] A load test on a yarn bundle 6 formed by bundling three heat-set crimped yarns will be described with reference to Figures 11 and 12. Figure 11 is a schematic diagram showing the procedure for conducting the load test. Figure 12 is a graph showing the results of the load test. As shown in Figure 11, the yarn bundle 6 was fixed at an upper end point P1 of the test section, hung down vertically, and had a weight 61 attached to a lower end point P2 of the test section. The amount of displacement of a midpoint P3 between the upper end point P1 and the lower end point P2 was observed before and after the yarn bundle 6 was pulled toward the ground by the weight 61.

[0050] In Figure 12, the dashed line L1 indicates the load curve when a non-crimpable yarn is used as the core yarn. The dashed line L2 indicates the load curve when a crimpable yarn with a relatively small heat shrinkage rate is used as the core yarn. The solid line L3 indicates the load curve when a crimpable yarn with a relatively large heat shrinkage rate is used as the core yarn. As can be seen from L2 and L3, the use of a crimpable yarn as the core yarn allows the fastener tape 3 to be stretched to a greater extent. This means that the length of the side edge portion 31 of the fastener tape 3 can be easily adjusted after heat setting, and serves as a countermeasure against excessive crimping of the core yarn 51.

[0051] It is preferable to use a crimped yarn having an elongation of 7% or more. For example, it is preferable to use a crimped yarn having an elongation in the range of 7% to 10%. The elongation of the crimped yarn is evaluated in the load test shown in Figure 11, and specifically, it is calculated as the elongation when a weight of a predetermined mass is attached to a bundle of three crimped yarns ((stretched length - original length) / original length) x 100.

[0052] A method for manufacturing the fastener tape 3 will be described with reference to FIG. 13 . First, a fastener tape 3 with a core 5 is formed (S1). Specifically, the fastener tape 3 is formed with the core 5 provided at the side edge 31. An automatic loom or an automatic knitting machine can be used for this purpose. When the core 5 is a core cord to be woven into the fastener tape 3, step S1 may include a step of forming the core 5 as a core cord and a step of weaving the fastener tape 3 including the core 5. The step of forming the core 5 as a core cord may include a step of drawing together multiple core yarns 51 and a step of forming a tubular portion 52 around the bundle of multiple core yarns 51 (see FIG. 6 ). The tubular portion 52 is preferably knitted as a knitted structure. In the step of weaving the fastener tape 3 including the core 5, the core 5 is constrained by a weft yarn and woven into the fastener tape 3. As shown in FIGS. 2 and 3 , a pair of upper and lower cores 5 (core cords) may also be woven into the fastener tape 3.

[0053] Next, the fastener tape 3 is heat-set (i.e., heated) so that the crimpable yarns are crimped (S2). The set temperature for heat-setting depends on the material of the crimpable yarns, but for example, the set temperature of a heat source such as a heater is set to a temperature within the range of 160°C to 200°C. The heat source and the side edge portion 31 of the fastener tape 3 are positioned closely opposite each other, and the side edge portion 31 of the fastener tape 3 is heated. Different polymer materials in the crimpable yarns used as the core yarn 51 thermally shrink to different degrees. As a result, the crimpable yarns crimp, the length of the core portion 5 becomes shorter, and the stringer bias becomes positive. A heater can be arranged along the transport path of the fastener tape 3. The heater is, for example, an electric heater that generates heat by electrical heating, but other types of heaters can also be used.

[0054] Next, the fastener tape 3 is subjected to a first post-treatment (S3). The first post-treatment may include a dyeing process of the fastener tape 3. The fastener tape 3 can be transported to a dyeing tank storing a dye solution or to the discharge port of an inkjet printer for dyeing using a plurality of rolls (for example, rollers 101 and 102 shown in FIG. 14). The fastener tape 3 runs along a running path determined by the plurality of rollers while tension is applied in the longitudinal direction. Therefore, the degree of crimp of the crimpable yarn is reduced, and the degree of positive stringer bias is weakened.

[0055] Next, the second post-treatment is carried out on the fastener tape 3 (S4). The second post-treatment may include a drying step of the fastener tape 3. In the drying step, the fastener tape is reheated. For this purpose, a heater can be used as described above. If dyeing is carried out in the first post-treatment step, the fastener tape 3 to which the dye solution has adhered or penetrated is dried. In either case, the degree of crimp of the crimpable yarn used as the core yarn 51 is increased by thermal shrinkage.

[0056] After step S2, at least one step of reducing the degree of crimp of the crimpable yarn and at least one step of increasing the degree of crimp of the crimpable yarn may be performed simultaneously or in this order to facilitate achieving an appropriate stringer bias in the fastener tape 3. The first and second post-treatment steps (S3, S4) include a treatment for reducing the degree of crimp of the crimpable yarn, and a treatment for increasing the degree of crimp of the crimpable yarn. As a result, even if the stringer bias of the fastener stringer 2 becomes excessively positive in the heat-setting step (S2), the stringer bias can be naturally transitioned to an appropriate state after the first and second post-treatment steps.

[0057] Steps S3 and S4 are not limited to dyeing and drying steps. When the fastener tape 3 is placed in the cavity of the injection mold, tension is also applied to the fastener tape 3 in its longitudinal direction. Furthermore, the fastener tape 3 is also heated in response to heat transmitted from the molten resin or the mold during injection molding. In this case, the first post-treatment step (stretching the fastener tape 3 in the mold cavity) and the second post-treatment step (thermal shrinkage of the crimpable yarn in response to heat transmitted from the mold) are carried out simultaneously.

[0058] As shown in Fig. 15, it is also possible to form a tubular portion 52 as a hollow weave 38 in a part of the ground structure 37 of the fastener tape 3, and introduce a core yarn 51 into this tubular portion 52. In this case, the same effect as described above can be obtained.

[0059] As shown in Fig. 16, a coil element can also be used as the fastener element 4. The coil element is sewn to the main tape surface (e.g., the lower tape surface) of the fastener tape 3. A core 5 is provided on the opposite side of the fastener tape 3. Specifically, one of the cores (e.g., only the upper core 5m) in Figs. 2 and 3 is woven into the fastener tape 3 (the lower core 5n in Figs. 2 and 3 is omitted). Other configurations are also possible.

[0060] In light of the above teachings, those skilled in the art can make various modifications to the embodiments. The reference numerals included in the claims are for reference purposes only and should not be used to limit the scope of the claims.

[0061] 1: Slide fastener 2: Fastener stringer 3: Fastener tape 4: Fastener element 5: Core portion 7: Composite yarn 9: Slider 31: Side edge portion 32: Side edge portion 33: Main portion of tape 35: Warp yarn 36: Weft yarn 37: Ground structure 51: Core yarn 52: Cylinder portion 52a-52d: Leather yarn

Claims

1. A fastener tape comprising: a core portion (5) provided at a side edge portion (31) of a fastener tape (3) to which a fastener element (4) is attached; the core portion (5) including at least one core thread (51) and a tubular portion (52) surrounding the at least one core thread (51); and the at least one core thread (51) including a shrinkable thread that is shrinkable in accordance with the difference in thermal shrinkage rates of different polymeric materials.

2. The fastener tape according to claim 1, wherein the core portion includes a total of N (N is a natural number of 2 or more) core yarns as the at least one core yarn, and each of the total N core yarns is the crimpable yarn.

3. 3. The fastener tape according to claim 2, wherein the crimpable yarn is a composite yarn in which threads made of at least two kinds of polymeric materials having different heat shrinkage rates are bonded together.

4. The fastener tape according to claim 3, wherein the crimpable yarn is a composite yarn in which at least two kinds of polymer materials having different heat shrinkage rates are spun together.

5. The core portion is a core cord woven into the fastener tape, The fastener tape according to claim 3 or 4, wherein the tubular portion includes a braided structure in which a plurality of shear threads are braided.

6. The fastener tape described in claim 5, which does not contain any shrinkable yarns that shrink in accordance with the difference in thermal shrinkage rates of different polymeric materials, except for the total N core yarns.

7. A fastener tape as described in claim 3 or 4, wherein the shrinkable yarn has an elongation within the range of 7% to 10%.

8. A fastener tape as described in claim 3 or 4, wherein the total of N core yarns are doubled yarns pulled together in the warp direction or twisted yarns twisted together along the warp direction, and the core portion includes only crimpable yarns as the total of N core yarns.

9. The fastener tape according to any one of claims 1 to 4, A fastener stringer including a fastener element attached to the side edge of the fastener tape.

10. A process for forming a fastener tape having a core portion provided on one side edge portion, the core portion including at least one core thread and a tubular portion surrounding the at least one core thread, the at least one core thread including a crimpable thread that is crimped in accordance with a difference in thermal shrinkage rate between different polymer materials; A method for producing a fastener tape, comprising the step of heating the fastener tape so that the crimpable yarn is crimped.

11. The method for producing a fastener tape according to claim 10, further comprising the step of stretching the fastener tape along its longitudinal direction so as to reduce the degree of crimping of the crimpable yarn after the step of heating the fastener tape.

12. The method for producing a fastener tape according to claim 11, wherein the fastener tape is stretched by running along a running path defined by a plurality of rollers while tension is applied in the longitudinal direction of the fastener tape.

13. The method for producing a fastener tape according to claim 11 or 12, further comprising the step of reheating the fastener tape after the step of stretching the fastener tape so as to increase the degree of crimp of the crimpable yarn.

14. The method for producing a fastener tape according to claim 13, further comprising a step of dyeing the fastener tape, and the step of reheating the fastener tape is carried out in a process of drying the fastener tape with the dyeing solution adhered thereto by the step of dyeing the fastener tape, by heating.

15. The method for producing a fastener tape according to claim 10, wherein after the step of heating the fastener tape, at least one step of reducing the degree of crimp of the crimpable yarn and at least one step of increasing the degree of crimp of the crimpable yarn are performed simultaneously or in this order.