JP2012214007A - Method for manufacturing coil comprising thermoplastic polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil which is mainly composed of non-metal materials and easily molded at low cost without a complex manufacturing process, and flexibly supports various coil wire thickness, coil shape and size.SOLUTION: In a method for manufacturing a coil comprising thermoplastic polymers, a fiber bundle comprising a plurality of fibers, wherein the fiber bundle is composed of a low melting point polymer and a high melting point polymer, is used, the fiber bundle is wound to be a specific spiral-shape, then a heat treatment is performed at a temperature that the low melting point polymer composing the fiber bundle is melted and the high melting point polymer is not melted, and then the fiber bundle is cooled.

Description

  The present invention relates to a coil made of a thermoplastic polymer.

  Conventionally, coils have been used as members of various appliances and devices such as automobiles, bedding, instruments, writing instruments, and pump dispensers for purposes such as shock absorption, energy storage, load adjustment, load detection, and vibration isolation. As a material of the coil, there are a material made of a metal such as a stainless steel material, a spring steel material, a piano wire material and a white wire material, and a material made of a non-metallic material such as a synthetic resin, FRP and synthetic fiber.

  In general, a metal coil has a higher elastic modulus than a synthetic resin, and can exhibit mechanical properties even with a member having a smaller cross-sectional area than a synthetic resin. In addition, since the physical properties are relatively stable with respect to operating environments such as temperature, the application range is wide. However, there are problems that it is inferior in durability such as being easily corroded by chemicals and easily rusting, and that it cannot be colored, and when used as a member in a resin product, it is difficult to separate and collect. Furthermore, there is a demand for weight reduction, and the development of non-metallic coils is underway.

  Synthetic resins are inferior in heat resistance and mechanical properties compared to metals, but they are superior in durability, such as lightness, wear resistance, and chemical resistance. It has features such as high insulation. Moreover, coloring can also be performed easily and special-shaped shaping | molding can be performed easily. Furthermore, when used as a member in a resin product, there is an advantage that it is easy to separate and collect.

  As such a synthetic resin coil, Patent Document 1 proposes a synthetic resin coil. Although it is almost impossible to separate metal coils incorporated in a synthetic resin product, this problem is solved by using synthetic resin-molded synthetic resin coils. Moreover, a required sufficient elasticity is ensured by combining a plurality of pieces in a spiral state and integrally forming them.

  Patent Document 2 proposes a coil spring using a carbon fiber reinforced resin using a carbon fiber having mechanical properties as a reinforcing material. Compared to resin coils, it has excellent mechanical properties.

  Known methods for producing these synthetic resin coils include an integral molding method, a method in which a resin linear body is wound around a shaping shaft, and a method in which a resin linear body is wound around a heated shaping shaft. Yes. In the integral molding method, there is a problem that not only a huge cost is required for producing a molding die, but also the strength of the obtained molded product is inferior. In addition, in the method of heating in a state where the resin linear body is wound around the upper shaping shaft and the method of winding the resin linear body around the heated shaping shaft, the shaping shaft having a spiral groove is used. It is difficult to respond to changes in diameter and coil pitch, and in particular, the method of heating with the resin wire wound around the top shaping shaft cannot adopt a continuous manufacturing process. There is a problem that it is difficult to obtain a molded product having uniform dimensional stability and shape stability because unevenness in the thermal history of the resin linear body is likely to occur.

  In Patent Document 3, as a method of manufacturing a synthetic resin coil having good dimensional stability and shape stability, a synthetic resin monofilament is advanced in a tension state and preheated to a temperature not lower than the melting point and not lower than the glass transition temperature of the monofilament material. Thereafter, a method has been proposed in which the wound monofilament is immediately wound on a rotating shaping shaft, and then the wound monofilament is rapidly cooled. However, in this method, there is a limit to the diameter of the monofilament to be used, and it is difficult to combine with other materials for providing other performance.

JP-A-10-73138 JP 07-42778 A JP-A-11-254520

  An object of the present invention is a coil mainly made of a non-metallic material, and can be easily and inexpensively formed without going through a complicated manufacturing process. The coil wire thickness, coil shape, and size It is to provide a coil that can flexibly cope with the above.

  The present invention achieves the above-mentioned problems, and the gist of the present invention is to use a fiber bundle formed by bundling a plurality of fibers, and the fiber bundle is composed of a low-melting polymer and a high-melting polymer. After the fiber bundle is wound into a predetermined spiral shape, the low melting point polymer constituting the fiber bundle is melted, and heat treatment is performed at a temperature at which the high melting point polymer does not melt. And a method for producing a coil made of a thermoplastic polymer, characterized by cooling.

  Hereinafter, the present invention will be described in detail.

  In the present invention, first, a fiber bundling body formed by bundling a plurality of fibers is prepared. In the present invention, since a coil is obtained using a thermoplastic polymer as a main material, a synthetic fiber made of a thermoplastic polymer is used as the fiber constituting the fiber bundle. Synthetic fibers can be preferably used because they can easily adjust the fineness and mechanical properties. Synthetic fibers include polyamide-based, aromatic polyester-based, aliphatic polyester-based, polyolefin-based and polyurethane-based synthetic fibers. Polyamide-based synthetic fibers are preferred because of their excellent wear resistance. Polyester-based synthetic fibers are preferred because of their excellent dimensional stability. In addition, if the coil is used for an application that is required to be naturally decomposed after use, it is preferable to use an aliphatic polyester-based synthetic fiber having biodegradability. Polyolefin-based synthetic fibers have a small specific gravity and are excellent in weight reduction. Therefore, they are preferably used for applications that require weight reduction. Further, depending on the application and purpose, a plurality of these synthetic fibers may be selected and arbitrarily combined to form a fiber bundle. In the present invention, a coil is obtained using a thermoplastic polymer as a main material, but fibers other than the thermoplastic polymer can be included in the fiber bundle according to the use and purpose of the coil. Examples of fibers other than synthetic fibers include natural fibers, regenerated fibers, and semi-synthetic fibers. Moreover, you may include a metal wire, a metal fiber, and glass fiber.

  The fiber bundling body formed by bundling a plurality of fibers may be any fiber bundling as long as the fibers are bundled, a yarn obtained by arranging a plurality of fibers, a twisted yarn obtained by twisting a plurality of fibers, a spun yarn, Examples thereof include a twisted yarn obtained by combining drawn yarns and twisted yarns, a braid made using these yarns, a rope obtained by twisting, and the like. What is necessary is just to select suitably the thickness (wire diameter) of a fiber bundling body according to the magnitude | size etc. of the coil desired. In the present invention, the reason for using a fiber bundling body formed by bundling a plurality of fibers is that the fibers are simply bundled, so that there is flexibility between the fibers and it is very flexible. It is to be able to cope with various shapes. Therefore, according to the present invention, even if the thickness of the fiber bundle itself is large, it is flexible, so that it can be wound according to various winding diameters and winding pitches. It can be easily obtained.

  The fiber bundle is composed of a low melting point polymer and a high melting point polymer. The low-melting point polymer is melted and solidified by heat treatment later, and the fibers are fixed and integrated with each other to maintain a predetermined spiral shape. The high-melting point polymer is not melted by the heat treatment and is not melted. The form will be maintained and the mechanical properties of the coil will be borne. At this time, if the fiber bundle is formed only from the low melting point polymer, the low melting point polymer melts and flows during the heat treatment, and a predetermined spiral shape cannot be obtained. The mixing ratio of the low melting point polymer and the high melting point polymer is preferably about 10/90 to 70/30.

  In the present invention, a composite fiber in which a low-melting polymer and a high-melting polymer are composited, and a fiber in which the low-melting polymer is arranged on at least the fiber surface is contained as a fiber constituting the fiber assembly. By doing so, the fiber assembly can be formed of a low melting point polymer and a high melting point polymer. The composite fiber is also referred to as a composite binder fiber because it functions as a thermal binder by melting the low melting point polymer. In such a composite binder fiber, only the low melting point polymer is melted by heat treatment, and the fibers constituting the fiber bundle are fixed and integrated with each other, so that the fiber bundle becomes a rigid linear strip. The fiber bundle may be composed of the composite binder alone, or may contain other fibers. In addition, it is good to use the fiber which is maintaining the fiber form, without melt | dissolving by heat processing as the other fiber to contain. As the composite binder fiber, it is preferable to use a core-sheath type composite fiber in which a low melting point polymer forms a sheath part and a high melting point polymer forms a core part.

  Further, in the present invention, a fiber that constitutes a fiber bundle is contained as a fiber by including a binder fiber constituted only by a low-melting polymer and a high-melting fiber constituted only by a high-melting polymer as fibers constituting the fiber bundle. Aggregates can be formed from a low melting polymer and a high melting polymer. Since the binder fiber is composed only of a low-melting polymer, the fiber bundling body is formed as a rigid straight line by fixing and integrating the fibers of high-melting fibers that are melted by heat treatment and maintain the fiber form. It becomes. The fiber assembly may contain other fibers in addition to the above-described binder fibers and high melting point fibers. The other fibers to be contained may be other high melting point fibers that maintain the fiber form without being melted by heat treatment, or may be the above-described composite binder fibers, depending on the purpose and the like. What is necessary is just to select suitably.

  In the present invention, it is also possible to use a two-layered fiber bundle in which a layer containing a binder fiber and a layer not containing a binder fiber are arranged in a two-layer structure in the cross section of the fiber bundle. At this time, (1) a layer containing the binder fiber is arranged in the core layer of the fiber bundle, and a layer not containing the binder fiber is arranged in the surface layer (sheath layer) of the fiber bundle, or (2 ) A layer containing a binder fiber is arranged on the surface layer (sheath layer) of the fiber bundle, and a layer not containing the binder fiber is arranged in the core layer of the fiber bundle.

  In the above aspect (1), the binder fibers are not exposed on the surface of the fiber bundle of the two-layer structure described above. That is, in the cross section of the fiber bundle, only the high melting point fibers that are not affected by heat by the heat treatment are arranged in the outermost layer, and the binder fibers are not included. As a result, the low melting point component that is melted by the heat treatment is not melt exposed on the surface of the fiber bundle, so that it is easy after heat treatment to cooling without being melt-bonded to a mold such as a metal shaft for forming a spiral shape. Can be demolded. In addition, for example, in the case of a coil having a small coil pitch, it is possible to prevent the coils between adjacent pitches from being melt-bonded during heat treatment. In addition, in the coil obtained by heat treatment, the surface of the striate body constituting the coil retains the texture of the fiber without being affected by the heat treatment, so it has a soft texture and is warm to the fiber tone. Since it has a certain appearance, it is excellent in design.

  On the other hand, in the above-described aspect (2), in the above-described two-layered fiber bundle, the binder fiber is exposed on the surface of the fiber bundle. Since the surface part of the linear body which comprises the coil in the coil obtained by heat processing is comprised only from binder fiber, what comprises all the fiber bundling bodies only from binder fiber becomes a similar surface form. Therefore, since the surface of the obtained coil linear body exhibits the same form and the coil performance is comparable, it is advantageous in terms of cost by reducing the ratio of the binder fiber in the fiber bundle. . Further, when the core-sheath type composite binder fiber is used as the binder fiber, the coil performance such as the spring coefficient tends to be improved.

Specific examples of such a two-layer structure include air-processed yarn, blended yarn, and covering twisted yarn. In the above aspect (1), only the binder fiber or the composite binder fiber is arranged in the core layer of the yarn cross section of these yarns, or the binder fiber, the composite binder fiber and the high melting point fiber are arranged, and the sheath layer In this case, only the high melting point fiber is disposed without including the binder fiber or the composite binder fiber. In the mode (2), the arrangement is reversed.
Another specific example is a braid or a rope. In the above aspect (1), the braid is prepared by using a multifilament yarn including at least a binder fiber or a composite binder fiber, a plurality of the multifilament yarns aligned or combusted, or the multifilament yarn. Using the braids and the like as a core material (core layer), the outer layer (sheath layer) does not contain binder fibers and composite binder fibers, and multifilament yarns composed only of high-melting fibers are used to produce braids, Examples thereof include a fiber bundle composed of a braid having a two-layer structure in which a layer containing a binder fiber and a layer not containing a binder fiber have a two-layer structure. In the rope, a yarn in which a fiber group including a binder fiber is twisted and a yarn in which a fiber group composed only of a high melting point fiber not including a binder fiber is twisted are prepared. Twist in the opposite direction to the yarn by arranging the yarns composed of high-melting fibers only in the center of the rope (core layer) and the outer layer of the rope (sheath layer). A composite strand is formed by combining them, and three of these composite strands are combined and twisted in the opposite direction to the strands to obtain a rope. In the mode (2), the arrangement is reversed.

  As the low melting point polymer, any polymer having a spinning property by melt spinning may be used. For example, polyester polymer, polyamide polymer, polyolefin polymer, polybutyral polymer, polyacrylic polymer, polyethylene -A vinyl acetate copolymer, a polyurethane-type polymer, etc. are mentioned. The melting point of the low melting point polymer is preferably 20 ° C. or lower than the melting point of the high melting point polymer. This is because the high melting point polymer does not affect the physical properties by heat treatment. Further, the melting point of the low melting point polymer is preferably in the range of 80 to 160 ° C. in consideration of processability and physical properties. In consideration of adhesiveness, preferred combinations of the low melting point polymer / the high melting point polymer include low melting point polyester / high melting point polyester, low melting point polypropylene / high melting point polypropylene, polyethylene / polypropylene, low melting point nylon / high melting point nylon. The combination of these is mentioned. More specifically, a core-sheath type composite fiber in which a high melting point polyester having a melting point of 240 ° C. or higher is disposed in the core and a low melting point copolymer polyester having a melting point of 110 to 200 ° C. is disposed in the sheath, or a melting point of 180 ° C. or higher. A core-sheath type composite fiber in which a high melting point polyamide is disposed in the core and a low melting point polyamide having a melting point of 80 to 150 ° C. is disposed in the sheath is preferably used.

  It is preferable to use similar fibers as the fibers constituting the fiber bundle. Since the low-melting-point polymer and the high-melting-point polymer have good thermal adhesiveness, the fibers can be firmly fixed and integrated with each other, and a more rigid linear body can be obtained. In addition, using similar fibers is also preferable from the viewpoint of recycling. Therefore, when using a fiber other than the heat-sealing fiber, it is important to select a fiber that is excellent in the melting component and adhesion of the heat-sealing fiber during the heat treatment.

  The fineness of the fibers constituting the fiber bundling body only needs to be flexible when spirally wound, and is preferably about 3 to 20 dtex. Further, the fineness of the fiber bundling body only needs to be flexible when it is wound in a spiral shape, and the fineness of the filaments constituting the coil can be selected as appropriate according to the use of the coil. However, the lower limit is preferably about 500 dtex and the upper limit is about 5 million dtex. The fiber bundling body may be obtained by bundling 25 to several million fibers.

  Although the form of the fiber which comprises a fiber bundling body may be a short fiber or a continuous fiber, a continuous fiber is preferable. Since continuous fibers do not have fluff, fluff is not formed on the surface of the filaments obtained by stiffening the fiber bundle by heat treatment.

  In addition, you may add suitably to the fiber to be used in the range which does not impair the effect of this invention, such as a flame retardant, a coloring agent, a pigment, a lubricant, a weathering agent, antioxidant, and a heat-resistant agent generally used. Further, the fiber cross-sectional shape may be any of a round cross section, an irregular cross section, a hollow cross section, and the like. Moreover, the fiber which gave processing, such as false twist processing and taslan processing, to a fiber can also be used.

  In the present invention, after winding the above-described fiber bundled body into a predetermined spiral shape, the low-melting polymer is melted and heat-treated at a temperature at which the high-melting polymer does not melt, and then cooled. Then, the low-melting polymer obtained by melting and solidifying the fibers in the fiber bundle is fixed and integrated, so that the fiber bundle becomes a rigid linear body, the helical shape is fixed, and is made of a thermoplastic polymer. A coil can be obtained.

  In winding the fiber bundle so as to have a spiral shape, a predetermined shaping axis may be used. In the present invention, since the fiber bundling body has flexibility between fibers, any shape can be supported. Therefore, in order to obtain a desired coil, it can be set as appropriate according to the diameter of the shaping shaft, the pitch of the spiral, various cross-sectional shapes of the shaft, and according to changes in the shaft diameter and pitch. Moreover, the heating method is not particularly limited, but a known means such as an iron, a hot air welder, a hot air dryer, or a tenter machine may be used. The heat treatment temperature may be appropriately set in relation to the heat treatment time, but is set to a temperature not lower than the melting point of the high melting point polymer and not lower than the melting point of the high melting point polymer.

  Cool after heat treatment. By cooling, the melted low-melting point polymer is solidified, and the fibers constituting the fiber bundle are fixed and integrated, and the fiber bundle becomes a rigid linear body (rigid straight line body). By this treatment, a coil in which the rigid linear strip composed of the thermoplastic polymer has an arbitrary spiral shape is obtained. As a cooling means, known means such as air cooling or water cooling may be used.

  In the present invention, a flexible fiber bundling body formed by bundling a plurality of specific fibers is wound into an arbitrary spiral shape, and then subjected to heat treatment to form a fiber bundling body. The coil is obtained as a rigid linear strip by fixing and integrating the gaps, and the rigid filament having a spiral shape has various diameters such as the diameter of the filament, the spiral shape and the pitch of the spiral. Any helical shape can be applied as desired. In addition, a coil made of a thermoplastic polymer can be easily formed into a spiral shape at low cost without going through a complicated manufacturing process.

Next, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. The spring characteristics of the coils obtained in the examples were evaluated as follows.
<Spring constant>
In accordance with JIS B 2704, the spring constant (N / mm) is obtained by the following formula using two types of loads A and B, which are deflections between 30 and 70% of the natural height when a load is applied. It was.
C = (MA-MB) / (LA-LB)
(C: spring constant,
MA: Mass of load A (N),
MB: Mass of load B (N),
LA: Deflection when load A is applied (mm),
LB: Deflection when load B is applied (mm))

Example 1
As the fiber constituting the fiber bundle, only a concentric core-sheath type composite fiber (binder fiber) in which a low melting point polymer is arranged in the sheath part and a high melting point polymer is arranged in the core part was used. The core-sheath type composite fiber is a copolymer of 12 mol% of ε-caprolactone with respect to the total number of moles of ε-caprolactone and the total alkylene terephthalate unit whose sheath is composed of ethylene terephthalate and butylene terephthalate (molar ratio 1/1). Copolyester (melting point: 161 ° C.), polyethylene terephthalate (melting point: 260 ° C.) at the core, and composite spinning with a core / sheath mass ratio of 2.7 / 1. 1670 decitex / 192f multifilament yarn was prepared.

  The multifilament yarn was used to form a string with eight corners to obtain a braid having an outer diameter of 1.4 mm, which was used as a fiber bundle.

  A fiber bundling body (braid) is wound around a metal shaft, and in this wound state, hot air treatment is performed under conditions of 180 ° C. × 10 minutes, demolded after air cooling, an inner diameter of 9.5 mm, a natural height of 10 mm, A coil composed of a thermoplastic polymer having 5 effective turns was obtained. The spring constant of the obtained coil was 0.032 N / mm.

Example 2
Using the core-sheath type composite fiber used in Example 1, as a multifilament yarn of 1100 dtex / 96f, the multifilament yarn was used to form a string with eight corners to obtain a braid having an outer diameter of 1.1 mm, This was used as a fiber bundle.
Using the obtained fiber bundle (braid), a coil constituted by a thermoplastic polymer having an inner diameter of 9.5 mm, a natural height of 10 mm, and an effective winding number of 5 was obtained in the same manner as in Example 1. The spring constant of the obtained coil was 0.022 N / mm.

Example 3
Using the core-sheath type composite fiber used in Example 1, as a multifilament yarn of 560 decitex / 48f, the multifilament yarn was used to form a string with eight corners, and a braid having an outer diameter of 0.7 mm was obtained. This was used as a fiber bundle.
Using the obtained fiber bundle (braid), a coil composed of a thermoplastic polymer having an inner diameter of 9.5 mm, a natural height of 10 mm, and an effective winding number of 5 was obtained in the same manner as in Example 1. The spring constant of the obtained coil was 0.0051 N / mm.

Example 4
As fibers constituting the fiber bundle, binder fibers composed only of a low-melting polymer and high-melting fibers composed only of a high-melting polymer were used. The binder fiber is a copolymerized polyester (melting point) obtained by copolymerizing 12 mol% of ε-caprolactone with respect to the total number of moles of ε-caprolactone and the entire alkylene terephthalate unit composed of ethylene terephthalate and butylene terephthalate (molar ratio 1/1). 161 ° C.), and the high melting point fiber is made of polyethylene terephthalate (melting point 260 ° C.). Multi-filament yarns (560 decitex / 60f) aligned with binder fibers and multi-filament yarns (560 decitex / 96f) aligned with high-melting fibers are aligned at 1/1 mixing ratio (mass ratio) to 1120 decitex A / 156f multifilament yarn was prepared.

The mixed multifilament yarn was used to form a string with eight corners to obtain a braid with an outer diameter of 1.1 mm, which was used as a fiber bundle.
Using the obtained fiber bundle (braid), a coil composed of a thermoplastic polymer having an inner diameter of 9.5 mm, a natural height of 10 mm, and an effective winding number of 5 was obtained in the same manner as in Example 1. The spring constant of the obtained coil was 0.011 N / mm.

Example 5
As fibers constituting the fiber bundle, binder fibers composed only of the low melting point polymer used in Example 4 and high melting point fibers composed only of the high melting point polymer were used. A 560 dtex / 96 f multifilament yarn composed only of high melting point fibers and a 560 dtex / 60 f multifilament yarn composed only of binder fibers were prepared.

Using a multifilament yarn composed only of high-melting fibers, making a string with eight corners, using the obtained braid as a core portion, and further forming a multifilament yarn composed only of binder fibers in the sheath portion A pair of braids having a two-layer structure was obtained by using eight pairs. The resulting braided cord having a two-layer structure with an outer diameter of 1.1 mm was used as a fiber bundle.
Using the obtained fiber bundle (braid), a coil composed of a thermoplastic polymer having an inner diameter of 9.5 mm, a natural height of 10 mm, and an effective winding number of 5 was obtained in the same manner as in Example 1. The spring constant of the obtained coil was 0.0072 N / mm. In addition, the coil surface was completely melted, had almost no irregularities, and had a smooth surface.

Example 6
The core-sheath type composite fiber used in Example 1 was used as a fiber constituting the fiber bundle, and a multifilament yarn of 560 dtex / 48f was obtained. In addition, a 560 dtex / 96f multifilament yarn composed of only the high-melting fiber was used using the high-melting fiber composed only of the high-melting polymer used in Example 4.
Using a multifilament yarn composed only of a core-sheath type composite fiber, a string is made with eight corners and a braid with an outer diameter of 1.1 mm is obtained. Using this braid as a core part, A multi-layered yarn composed of only melting point fibers was assembled into 8 groups to obtain a braid having a two-layer structure. The obtained braided cord having a two-layer structure was used as a fiber bundle.
Using the obtained fiber bundle (braid), a coil composed of a thermoplastic polymer having an inner diameter of 9.5 mm, a natural height of 10 mm, and an effective winding number of 5 was obtained in the same manner as in Example 1. The spring constant of the obtained coil was 0.019 N / mm. The fiber on the coil surface was not melted, and the surface was soft leaving the texture of the fiber.

Example 7
Using a 560 dtex / 96f multifilament yarn composed only of the high melting point fibers used in Example 6, an eight-cornered string was made to obtain a braid having an outer diameter of 1.1 mm. As a further example, eight multi-filament yarns of 560 dtex / 48f made only of the core-sheath type composite fiber used in Example 6 were assembled in the sheath portion to obtain a braid having a two-layer structure. The obtained braided cord having a two-layer structure was used as a fiber bundle.
Using the obtained fiber bundle (braid), a coil composed of a thermoplastic polymer having an inner diameter of 9.5 mm, a natural height of 10 mm, and an effective winding number of 5 was obtained in the same manner as in Example 1. The spring constant of the obtained coil was 0.034 N / mm. The sheath component of the core-sheath type composite fiber on the coil surface was melted, and the surface form of the coil filament was the same as that of Example 1.

Comparative Example As a fiber constituting the fiber bundle, only the binder fiber used in Example 4 was used, and a 1100 dtex / 120f multifilament yarn composed only of the binder fiber was prepared. This multifilament yarn was used to form a string with eight corners to obtain a braid with an outer diameter of 1.1 mm, which was used as a fiber bundle.
When the obtained fiber bundling body (braid) was heat-treated in the same manner as in Example 1, all the fibers melted, and the melt flowed down from the metal shaft, so that a coil could be obtained. There wasn't.

Claims (8)

After a fiber bundling body formed by bundling a plurality of fibers, the fiber bundling body is composed of a low melting point polymer and a high melting point polymer, and the fiber bundling body is wound into a predetermined spiral shape. Manufacturing a coil comprising a thermoplastic polymer, wherein the low-melting polymer constituting the fiber bundle is melted and heat-treated at a temperature at which the high-melting polymer does not melt, and then cooled. Method. 2. The fiber bundle is formed into a rigid straight strip by heat-treating and fixing and integrating the fibers in the fiber bundle by melting and solidifying a low melting point polymer. The manufacturing method of the coil which consists of a thermoplastic polymer.   3. The thermoplastic polymer according to claim 1, wherein a core-sheath type composite fiber in which a low melting point polymer forms a sheath part and a high melting point polymer forms a core part is included in the fiber bundle. The manufacturing method of the coil which consists of. The thermoplastic polymer according to any one of claims 1 to 3, wherein the fiber bundle includes a binder fiber made of only a low-melting polymer and a high-melting fiber made of only a high-melting polymer. The manufacturing method of the coil which consists of. The fiber bundle is a fiber bundle having a two-layer structure in which a layer containing a binder fiber and a layer not containing a binder fiber are arranged so as to have a two-layer structure in its cross section. A method for producing a coil comprising the thermoplastic polymer according to claim 4. 6. The method for producing a coil made of a thermoplastic polymer according to claim 5, wherein a layer not containing binder fibers is disposed on the outermost layer in the cross section of the fiber bundle. The method for producing a coil made of a thermoplastic polymer according to any one of claims 1 to 6, wherein the fibers constituting the fiber assembly are continuous fibers. The coil obtained by the manufacturing method of the coil which consists of a thermoplastic polymer of any one of Claims 1-7.