Core-sheath type composite monofilament and method for manufacturing the same

Abstract

To provide a core-sheath type composite monofilament with improved abrasion resistance. [Solution] This core-sheath composite monofilament has a core component which is a resin composition containing a polyvinylidene fluoride resin, a polyester thermoplastic elastomer, and a low-density polyamide resin, and a sheath component which is a polyamide resin. The sheath component may also contain silicone oil as a mold release agent. The overall cross-sectional shape of the core-sheath composite monofilament is circular. The cross-sectional shape of the core component is circular or multi-lobed. A multi-lobed shape has multiple leaf portions 1 which are outwardly protruding parts, and a central portion 2 inside the leaf portions 1. This core-sheath composite monofilament is suitably used as fishing line.

Description

Technical Field

[0001] The present invention relates to a core - sheath composite monofilament in which a core component contains a polyvinylidene fluoride - based resin, a thermoplastic elastomer, and a polyethylene - based resin, and a sheath component is made of a polyamide - based resin, and a method for producing the same. In particular, the present invention relates to a core - sheath composite monofilament suitable for use as a core yarn for fishing lines or strings of tennis rackets and a method for producing the same.

Background Art

[0002] Conventionally, a core - sheath composite monofilament in which a core component is a polyvinylidene fluoride - based resin and a sheath component is a polyamide - based resin has been known (Patent Documents 1 and 2). The reason for compounding a polyvinylidene fluoride - based resin and a polyamide - based resin is to achieve an appropriate specific gravity for a fishing line, that is, to have a specific gravity lower than that of the polyvinylidene fluoride - based resin and higher than that of the polyamide - based resin.

[0003] The present inventors have proposed the invention described in Patent Document 3 as an improved invention of the invention described in Patent Document 2. The invention described in Patent Document 3 employs a resin composition containing a polyvinylidene fluoride - based resin and a thermoplastic elastomer as a core component, aiming to improve the adhesion between the core component and the sheath component and provide a core - sheath composite monofilament with high wear strength.

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] The present invention is an improved version of the invention described in Patent Document 3, and its objective is to provide a core-sheath type composite monofilament that further improves abrasion resistance by further enhancing the adhesion between the core component and the sheath component, and that is less prone to yarn irregularities during manufacturing. [Means for solving the problem]

[0006] The present invention solves the above problems by composing the core component with a resin composition containing a polyvinylidene fluoride resin, a thermoplastic elastomer, and a polyethylene resin. Specifically, the present invention relates to a core-sheath type composite monofilament in which the core component is a resin composition containing a polyvinylidene fluoride resin, a thermoplastic elastomer, and a polyethylene resin, and the sheath component is a polyamide resin, wherein the cross-sectional shape of the entire core-sheath type composite monofilament is circular, and to a method for manufacturing the same.

[0007] The core-sheath type composite monofilament according to the present invention uses a resin composition containing a polyvinylidene fluoride resin, a thermoplastic elastomer, and a polyethylene resin as the core component, and a polyamide resin as the sheath component. As the polyvinylidene fluoride resin, a homopolymer of vinylidene fluoride (polyvinylidene fluoride) or a vinylidene fluoride copolymer of vinylidene fluoride and other monomers can be used alone or in combination. As the other monomers, any monomer that copolymerizes with vinylidene fluoride can be used, for example, tetrafluoroethylene, monochlorotrifluoroethylene, vinyl fluoride, hexafluoropropylene, or perfluoroisopropoxyethylene can be used alone or in combination. A thermoplastic elastomer is a polymeric substance that exhibits fluidity when heated and becomes highly elastic when returned to room temperature, and conventionally known materials can be used. For example, polyester thermoplastic elastomers, polyamide thermoplastic elastomers, or polystyrene thermoplastic elastomers can be used alone or in combination. Polyethylene resins are used to reduce the viscosity of polyvinylidene fluoride resins and improve their fluidity and deformability, and conventionally known types are used. For example, low-density polyethylene resins, high-density polyethylene resins, or polyethylene copolymer resins obtained by copolymerizing small amounts of other monomers such as ethylene-propylene copolymers are used.

[0008] The blending ratio of polyvinylidene fluoride resin to thermoplastic elastomer in the resin composition is approximately 1 to 10 parts by mass of thermoplastic elastomer per 100 parts by mass of polyvinylidene fluoride resin. If the blending ratio of thermoplastic elastomer is less than 1 part by mass, the adhesion between the core component and the sheath component tends to decrease. On the other hand, even if the blending ratio of thermoplastic elastomer exceeds 10 parts by mass, the adhesion between the core component and the sheath component tends not to improve significantly. The blending ratio of polyvinylidene fluoride resin to polyethylene resin in the resin composition is approximately 1 to 6 parts by mass of polyethylene resin per 100 parts by mass of polyvinylidene fluoride resin. If the blending ratio of polyethylene resin is less than 1 part by mass, the decrease in viscosity of the polyvinylidene fluoride resin is less, and the occurrence of yarn unevenness tends to occur during the manufacturing of core-sheath composite monofilaments. When yarn unevenness occurs, the abrasion strength at that location decreases, and the abrasion strength of the core-sheath composite monofilament decreases. On the other hand, if the proportion of polyethylene resin exceeds 6 parts by mass, the viscosity of the polyvinylidene fluoride resin tends to decrease too much. The resin composition may contain small amounts of other resins besides the polyvinylidene fluoride resin, thermoplastic elastomer, and polyethylene resin. In addition, the resin composition may contain small amounts of heat stabilizers, colorants, antioxidants, or plasticizers, either individually or in combination.

[0009] In the present invention, the overall cross-sectional shape of the core-sheath composite monofilament is circular. A cross-sectional shape with corners is undesirable because it reduces abrasion resistance. On the other hand, the cross-sectional shape of the core component is arbitrary, and specifically, it is preferably circular or multi-lobed. When the cross-sectional shape of the core component is circular, it is preferable that it be a concentric core-sheath composite monofilament. If it is an eccentric core-sheath composite monofilament, there is a higher risk of the core component being exposed due to abrasion at thin areas of the sheath component, and the core component and sheath component tend to separate. It is also preferable that the cross-sectional shape of the core component be multi-lobed. Here, multi-lobed refers to having multiple outwardly protruding parts (leaf portions 1), as shown in Figures 1 to 3. Figures 1 to 3 have six leaf portions 1, so it is a hexa-lobed shape. A central portion 2 exists inside the leaf portions 1. In the present invention, it is preferable to have three to eight leaf portions 1, that is, a tri-lobed to octa-lobed shape is preferred. If the cross-section is less than three-lobed, there are too few protruding parts, which tends to result in poor adhesion to the sheath component. Conversely, if the cross-section exceeds eight-lobed, the cross-section tends to approximate a circle, which also tends to result in poor adhesion to the sheath component.

[0010] The polyamide resin, which is the sheath component, surrounds the resin composition, which is the core component. The polyamide resin is not particularly limited as long as it has an amide group in its molecule, and for example, nylon 6, nylon 66, nylon 69, nylon 46, nylon 610, nylon 1010, nylon 11, nylon 12, nylon 6T, nylon 9T, or polymetaxylene adipamide 7 can be used alone or in combination. In the present invention, it is preferable to add and mix a release agent to the polyamide resin. Conventional release agents can be used, specifically silicone-based release agents and fluorine-based release agents. In particular, it is preferable to use silicone oil or fluorine oil that is liquid at room temperature. Adding and mixing a release agent to the polyamide resin reduces the coefficient of friction on the surface of the sheath component, and the wear resistance is further improved. The mixing ratio of the release agent to 100 parts by mass of polyamide resin is preferably about 0.1 to 10 parts by mass. Furthermore, polyamide resins may contain small amounts of other resins, and may also contain small amounts of additives such as heat stabilizers, colorants, antioxidants, or plasticizers, either individually or in combination.

[0011] The specific gravity of polyvinylidene fluoride is approximately 1.78, but since the core component consists of a resin composition containing polyvinylidene fluoride resin, thermoplastic elastomer, and polyethylene resin, its specific gravity is slightly lower, approximately 1.7. Since the sheath component is mainly polyamide resin, its specific gravity is generally in the range of 1.01 to 1.15. Therefore, the specific gravity of the core-sheath composite monofilament can be appropriately adjusted by the volume ratio of the core component to the sheath component. In the core-sheath composite monofilament according to the present invention, the volume ratio of the core component is preferably 10 to 35 volume%, in which case the specific gravity of the core-sheath composite monofilament can be adjusted within the range of approximately 1.20 to 1.35. When the volume ratio of the core component falls below 10 volume%, and the specific gravity of the core-sheath composite monofilament falls below 1.20, it tends to float easily when used as fishing line. When the volume percentage of the core component exceeds 35% by volume, the flexibility of the core-sheath composite monofilament tends to decrease.

[0012] The wire diameter of the core-sheath type composite monofilament is arbitrary. When used as fishing line (including main line and leader), a diameter of 0.1 to 1.0 mm is preferred. When used as the core thread for monostrings in tennis rackets, a diameter of 0.8 to 1.0 mm is preferred to match the typical wire diameter of monostrings (approximately 1.33 to 1.41 mm). Furthermore, when used as the core thread for multistrings in tennis rackets, it is preferable to use a multifilament yarn made by bundling multiple monofilaments with a wire diameter of 1 to 7 μm.

[0013] The core-sheath type composite monofilament according to the present invention can be manufactured by compound melt spinning using a resin composition containing a polyvinylidene fluoride resin, a thermoplastic elastomer, and a polyethylene resin, and a polyamide resin, to obtain a core-sheath type composite undrawn filament in which the core component is made of the resin composition and the sheath component is made of the polyamide resin, and then drawing the undrawn filament under heating. Compound melt spinning is performed by spinning the core component from a spinning hole with an arbitrary cross-sectional shape, such as a spinning hole with a circular cross-section or a spinning hole with a cross-sectional shape similar to the shape in Figures 1 to 3, and then spinning the sheath portion from around it. Alternatively, the core component may be spun and combined from multiple adjacent spinning holes with circular cross-sections, and the sheath component may be spun from around it. By such compound melt spinning, a core-sheath type composite undrawn filament having a core component with a multi-lobed cross-section can be obtained.

[0014] The core-sheath type composite undrawn filament is optionally cooled and then drawn under heating. Heating may be carried out in a moist heat atmosphere such as in hot water or hot oil, or in a dry heat atmosphere such as in air or gas. Furthermore, drawing may be carried out in one stage or in multiple stages. For example, drawing may be carried out in a moist heat atmosphere in the first stage and in a dry heat atmosphere in the second stage. In the present invention, when the core component is multi-lobed, heat is more easily transferred to the central part 2 of the core component compared to a core component with a circular cross-section, which has the advantage of making it easier to draw the core component. The drawing ratio is arbitrary, but a total drawing ratio of 2 to 8 times is preferable. When the total drawing ratio is high, it is preferable to carry out drawing under heating in multiple stages in order to obtain a uniform yarn quality with less yarn unevenness.

[0015] The core-sheath type composite monofilament according to the present invention can be used as is as fishing line. Furthermore, to manufacture tennis racket strings using the core-sheath type composite monofilament according to the present invention, the core-sheath type composite monofilament can be used as the core thread, its surface can be covered with thin multifilament threads or thin monofilament threads, and then hardened with a resin such as polyurethane resin. The core-sheath type composite monofilament according to the present invention can be used not only as the core thread for fishing line or tennis racket strings, but also as aquatic materials such as fishing net threads, or for other conventionally known applications. [Effects of the Invention]

[0016] The core-sheath composite monofilament according to the present invention comprises a core component made of a resin composition containing a polyvinylidene fluoride resin, a thermoplastic elastomer, and a polyethylene resin, and a sheath component made of a polyamide resin. Since the thermoplastic elastomer in the resin composition has rubber-like high elasticity at room temperature, the adhesion between the core component and the sheath component is further improved, resulting in improved abrasion resistance. Furthermore, because the resin composition contains a polyethylene resin, the viscosity of the polyvinylidene fluoride resin is reduced, improving fluidity and deformability, so that unevenness in the yarn is less likely to occur during the manufacturing of the core-sheath composite monofilament, resulting in a uniform yarn quality and improved abrasion resistance. If the cross-sectional shape of the core component is multi-lobed, the adhesion between the core component and the sheath component is further improved, resulting in improved abrasion resistance. In addition, if the sheath component contains a release agent, the coefficient of friction on the surface of the core-sheath composite monofilament is reduced, resulting in improved abrasion resistance. Therefore, when the core-sheath type composite monofilament according to the present invention is used in fishing lines, it has the effect of being resistant to breakage even when subjected to repeated friction due to sliding against a fishing rod, etc. Similarly, when used as the core thread for tennis racket strings, it has the effect of being resistant to breakage even when subjected to repeated friction due to sliding, etc.

[0017] Furthermore, since the core component resin composition contains polyethylene resin, the core component follows the fluidity of the sheath component well during composite melt spinning, resulting in the ability to obtain a core-sheath type composite monofilament with less yarn unevenness. In addition, when the cross-sectional shape of the core component is multi-lobed, heat is easily transmitted to the central part of the core component during the stretching process under heating during the manufacturing of the core-sheath type composite monofilament, resulting in the ability to stretch the resin composition containing polyvinylidene fluoride resin, thermoplastic elastomer, and polyethylene resin well under the stretching conditions for polyamide fibers. [Examples]

[0018] Example 1 A resin composition was prepared by uniformly mixing 91 parts by mass of polyvinylidene fluoride resin (manufactured by Shandong Dexuan New Materials Co., Ltd., trade name "DY-11B"), a polyvinylidene fluoride-based resin; 5 parts by mass of polyester elastomer (manufactured by Mitsubishi Chemical Corporation, trade name "Modic GQ331"), a thermoplastic elastomer; and 4 parts by mass of low-density polyethylene resin (manufactured by Nippon Polyethylene Co., Ltd., trade name "UJ580"), a polyethylene-based resin. In addition, polyamide 6 / polyamide 66 copolymer resin (manufactured by DSM Corporation, trade name "Novamid 2030J") was prepared as a polyamide-based resin. Using a composite melt spinning apparatus with spinning holes in a concentric core-sheath structure, composite melt spinning was performed at a melting temperature of 270°C, with the resin composition as the core component and the polyamide-based resin as the sheath component, to obtain a concentric core-sheath type composite undrawn monofilament. Furthermore, the volume ratio of the resin composition to the polyamide resin was set to 20:80 for the composite melt spinning process. The resulting concentric core-sheath type composite undrawn filament had a circular cross-sectional shape, and the core component also had a circular cross-sectional shape.

[0019] The concentric core-sheath type undrawn composite filament was cooled by immersion in a 40°C water bath, then immersed in a 90°C warm bath and subjected to the first stage of drawing under a moist heat atmosphere. Next, the second stage of drawing was performed under a dry heat atmosphere of 180°C, followed by the third stage of drawing under a dry heat atmosphere of 200°C, resulting in a total drawing ratio of 5.8 times to obtain a concentric core-sheath type composite monofilament. The cross-sectional shape of the obtained concentric core-sheath type composite monofilament was circular, and the cross-sectional shape of the core component was also circular.

[0020] Example 2 Instead of the polyamide resin used in Example 1, 93 parts by mass of a polyamide 6 / polyamide 66 copolymer resin (manufactured by DSM Co., Ltd., trade name "Novamid 2030J") and 7 parts by mass of a masterbatch were added and mixed, and the resulting mixture was used as the polyamide resin. Otherwise, a core-sheath type composite monofilament was obtained in the same manner as in Example 1. The masterbatch used was a uniform mixture of 93 parts by mass of a polyamide 6 / polyamide 66 copolymer resin (manufactured by DSM Co., Ltd., trade name "Novamid 2030J") and 7 parts by mass of silicone oil (manufactured by Momentive, trade name "TSF451-3000"). The cross-sectional shape of the obtained concentric core-sheath type composite monofilament was circular, and the cross-sectional shape of the core component was also circular.

[0021] Example 3 A concentric core-sheath type composite monofilament was obtained in the same manner as in Example 2, except that the total draw ratio was changed to 6.0 times. The cross-sectional shape of the obtained concentric core-sheath type composite monofilament was circular, and the cross-sectional shape of the core component was also circular.

[0022] Example 4 The resin composition used in Example 1 and the polyamide resin used in Example 2 were prepared. The resin composition as the core component was melt-spun and combined from seven circular spinning holes 3 with a diameter of 0.5 mm arranged in proximity as shown in FIG. 4 under the condition of a melting temperature of 270°C. At the same time, the polyamide resin as the sheath component was melt-spun from around it for composite melt-spinning to obtain a core-sheath type composite undrawn monofilament. The volume ratio of the resin composition to the polyamide resin was set to resin composition: polyamide resin = 20:80 for composite melt-spinning. The cross-sectional shape of the obtained core-sheath type composite undrawn monofilament was circular, and the cross-sectional shape of the core component was hexagonal. This core-sheath type composite undrawn monofilament was drawn under the same conditions as in Example 1 except that the total draw ratio was 5.6 times to obtain a core-sheath type composite monofilament. The cross-sectional shape of the obtained core-sheath type composite monofilament was circular, and the cross-sectional shape of the core component was hexagonal.

[0023] Example 5 Instead of using low-density polyethylene resin (manufactured by Japan Polyethylene Corporation, trade name "UJ580"), a core-shell type composite monofilament was obtained in the same manner as in Example 4, except that high-density polyethylene resin (manufactured by Japan Polyethylene Corporation, trade name "HJ490") was used. The cross-sectional shape of the obtained core-shell type composite monofilament was circular, and the cross-sectional shape of the core component was hexagonal.

[0024] Comparative Example 1 A concentric core-shell type composite monofilament was obtained in the same manner as in Example 1, except that 100 parts by mass of polyvinylidene fluoride resin (manufactured by Shandong Dexuan New Materials Co., Ltd., trade name "DY-11B"), which is a polyvinylidene fluoride-based resin, was used as the core component without adding and mixing a thermoplastic elastomer and a polyethylene-based resin in the resin composition.

[0025] Comparative Example 2 A concentric core-shell type composite monofilament was obtained in the same manner as in Example 1, except that a resin composition in which 95 parts by mass of polyvinylidene fluoride resin (manufactured by Shandong Dexuan New Materials Co., Ltd., trade name "DY-11B"), which is a polyvinylidene fluoride-based resin, and 5 parts by mass of polyester-based elastomer (manufactured by Mitsubishi Chemical Corporation, trade name "Modic GQ331"), which is a thermoplastic elastomer, were uniformly mixed was used without adding and mixing a low-density polyethylene resin in the resin composition.

[0026] Comparative Example 3 A concentric core-shell type composite monofilament was obtained in the same manner as in Comparative Example 1, except that a polyamide-based resin containing silicone oil used in Example 2 was used as the polyamide-based resin.

[0027] Reference Example 1 A concentric core-shell type composite monofilament was obtained in the same manner as in Comparative Example 3, except that the resin composition used in Comparative Example 2 was used as the resin composition.

[0028] Reference Example 2 A core-shell type composite monofilament having a hexagonal cross-sectional shape of the core component was obtained in the same manner as in Example 4, except that the resin composition used in Comparative Example 2 was used as the resin composition.

[0029] The wire diameter, specific gravity, and abrasion strength of the core-sheath type composite monofilaments obtained in the examples, comparative examples, and reference examples were measured by the following method. The measurement results are shown in Table 1. (1) Wire diameter (mm) The wire diameter (mm) was measured using a Mitutoyo MDH-25MB digital micrometer. (2) Specific gravity The volume of the core-sheath composite monofilament was calculated based on the wire diameter, and the mass of the core-sheath composite monofilament was measured. The specific gravity was then calculated as mass / volume. Therefore, this specific gravity is synonymous with density. (3) Abrasion resistance (number of cycles) A metal rod with a diameter of 20 mm and #1500 grit sandpaper attached to its surface was used as the abrasion body. The sample (core-sheath type composite monofilament obtained in the examples, comparative examples, and reference examples) was brought into contact with this abrasion body at a 90-degree angle, a predetermined load was applied to one end of the sample, and reciprocating friction was performed with a stroke width of 120 mm and a stroke speed of 35 strokes / min. The number of reciprocations until the sample fractured was measured. Here, the predetermined load was set to the cross-sectional area (mm²) of the sample. 2 The load was set at 4.15 kg per unit. For example, if the cross-section was circular and the wire diameter was 0.287 mm, a load of 268 g was applied. The sample was measured with n=3, and the average value obtained for the number of cycles was taken as the abrasion strength (cycles).

[0030] [Table 1] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Wire diameter (mm) Specific gravity Abrasion resistance (cycles) ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 1 0.287 1.31 1270 Example 2 0.290 1.27 2851 Example 3 0.289 1.28 2726 Example 4 0.284 1.28 3407 Example 5 0.284 1.28 3401 Comparative Example 1: 0.285 1.34 451 Comparative Example 2: 0.283 1.30 585 Comparison Example 3 0.282 1.33 738 Reference example 1 0.282 1.33 1723 Reference example 2 0.284 1.27 2978 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[0031] From the results of the examples, comparative examples, and reference examples, it can be seen that the abrasion strength of each core-sheath type composite monofilament is in the order of Example 4 > Example 5 > Example 2 > Example 3 > Reference Example 2 > Reference Example 1 > Example 1 > Comparative Example 3 > Comparative Example 2 > Comparative Example 1. [Brief explanation of the drawing]

[0032] [Figure 1] This is a schematic diagram showing an example of the cross-sectional shape of the core component of the core-sheath type composite monofilament according to the present invention. [Figure 2] This is a schematic diagram showing another example of the cross-sectional shape of the core component of the core-sheath type composite monofilament according to the present invention. [Figure 3] This is a schematic diagram showing another example of the cross-sectional shape of the core component of the core-sheath type composite monofilament according to the present invention. [Figure 4] This is a schematic diagram showing an example of a spinning hole used for melt spinning of the core component in Example 4, Example 5, and Reference Example 1. [Explanation of symbols]

[0033] 1. Leaf portion of the core component 2. Central part of the core component 3. Spinner hole

Claims

1. A core-sheath composite monofilament in which the core component is a resin composition containing a polyvinylidene fluoride resin, a thermoplastic elastomer, and a polyethylene resin, and the sheath component is a polyamide resin, wherein the overall cross-sectional shape of the core-sheath composite monofilament is circular.

2. The core-sheath type composite monofilament according to claim 1, wherein the cross-sectional shape of the core component is circular.

3. The core-sheath type composite monofilament according to claim 1, wherein the cross-sectional shape of the core component is multi-lobed.

4. The core-sheath type composite filament according to claim 1, wherein the thermoplastic elastomer is a polyester-based thermoplastic elastomer.

5. The core-sheath type composite monofilament according to claim 1, wherein the sheath component contains a release agent.

6. The core-sheath type composite monofilament according to claim 5, wherein the release agent is a silicone-based release agent.

7. The core-sheath type composite monofilament according to claim 3, wherein the multi-lobed shape is tri-lobed to octa-lobed.

8. The core-sheath type composite monofilament according to claim 1, wherein the volume percentage of the core component is 10 to 35 volume%.

9. A fishing line comprising a core-sheath type composite monofilament according to any one of claims 1 to 8.

10. A tennis racket string using a core-sheath type composite monofilament as the core thread, according to any one of claims 1 to 8.

11. A method for producing a core-sheath composite monofilament, characterized by compound melt spinning using a resin composition containing a polyvinylidene fluoride resin, a thermoplastic elastomer, and a polyethylene resin, and a polyamide resin, to obtain a core-sheath composite undrawn filament having a circular cross-sectional shape, in which the core component is made of the resin composition and the sheath component is made of the polyamide resin, and then drawing the undrawn filament under heating.

12. A method for manufacturing a core-sheath type composite monofilament according to claim 11, wherein the cross-sectional shape of the core component is circular.

13. A method for producing a core-sheath type composite monofilament according to claim 11, wherein the cross-sectional shape of the core component is multi-lobed.

14. A method for producing a core-sheath type composite monofilament according to claim 11, comprising compound melt spinning a polyamide resin to which a mold release agent has been added.

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