Dial lacing system laces

Abstract

To provide a string for a dial type lacing system, the string having high tensile strength, knot strength, and knot strength holding rate, having excellent flex resistance and abrasion resistance, and, therefore, being durable to not only short-term use but also repeated use for a long term.SOLUTION: A string for a dial type lacing system is obtained by coating with resin a core fiber composed of twisted yarn of a high-strength fiber multifilament. A value of a ratio of a diameter of the core fiber to a diameter of the string is 0.4 to 0.7.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to laces for use in dial lacing systems. [Background technology]

[0002] In recent years, dial-type lacing systems, such as the BOA (registered trademark) closure system, have been adopted for sports shoes such as golf shoes and snowboard shoes.

[0003] The dial-type lacing system allows you to tighten and loosen the laces with the dial, tightening the laces evenly and achieving a natural fit. It also has various advantages, such as being easy to tighten and loosen the laces and being able to instantly adjust the tightness. but They are used in a variety of products, including sports shoes, protective gloves, hats, and medical equipment. However, the laces are held in place by high tension, which places a large load on them.

[0004] If the string breaks, it can be replaced, but repairs are expensive, and even if you try to replace it yourself, it will be difficult to do so quickly unless you are accustomed to it, so it is necessary for the string to be able to withstand repeated use over a longer period of time.

[0005] Therefore, in order to reduce the load on the string, there is a technology that reduces the sharp angle of the string's direction changes in the guide section by changing the position and angle of the guide, and increases the radius of curvature of the string between the guides (Patent Document 1).

[0006] Examples of strings include unresin-coated twisted steel wire, resin-coated (e.g., polyamide-coated) twisted steel wire, monofilament (e.g., polyamide), and braided or twisted string made of high-density polyethylene Spectra (registered trademark). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-198952 Summary of the Invention [Problem to be solved by the invention]

[0008] The string is required to have high tensile strength and excellent flex resistance and abrasion resistance because it is repeatedly subjected to various large loads, such as tensile load due to tightening, bending load at the guide parts and bending parts inside the dial that support the string path, friction with the guide and friction between the strings themselves. Furthermore, when considering the entanglement of the strings and knots such as knots inside the dial, high knot strength and knot strength retention are also required.

[0009] Although twisted steel wires have high strength against tensile loads, bending can cause kinking, a phenomenon in which the twist tightens or unwinds locally, resulting in a decrease in strength. Furthermore, even resin coating cannot completely prevent kinking. When monofilaments are made thick enough to withstand high tensile loads, they become rigid and have poor bending resistance. Spectra® is also strong against tensile loads and does not kink. However, due to the structure of the braided cord, the length direction of the fibers is oblique to the direction of movement when loosening or tightening. This makes it prone to fibrillation due to friction with the guide and between the cords, resulting in a decrease in strength. Twisted wires, while not as susceptible to fibrillation as braided cords, also tend to fibrillate due to friction with the guide and between the cords, resulting in a decrease in strength. While fibrillation can be prevented by resin coating, Spectra® has a low heat resistance of 100°C, compared to the melting temperature of coating resins such as polyamide, which is 180 to 260°C. Therefore, the strength decreases depending on the melting temperature of the coating resin.

[0010] Although the position, angle, or material of the guides can reduce the bending and friction of the laces, in dial-type lacing systems, even if the direction change between the guides is at an obtuse angle, the laces still bend at acute angles inside the dial, resulting in places with a small radius of curvature. Furthermore, since the laces are subject to friction not only with the guides but also with the contact points between the laces and the gears inside the dial, laces must be able to withstand a variety of loads.

[0011] For the reasons described above, the lace exemplified in Patent Document 1 does not satisfy all of the requirements for tensile strength, knot strength, knot strength retention, flex resistance, and abrasion resistance when used repeatedly over a long period of time as a lace for a dial-type lacing system.

[0012] Therefore, an object of the present invention is to provide a lace for a dial-type lacing system that has high tensile strength, knot strength, and knot strength retention, and is excellent in bending resistance and abrasion resistance, and can therefore withstand repeated use over a long period of time. [Means for solving the problem]

[0013] The present inventors, after extensive investigations, have found that by coating a core fiber made of a twisted multifilament yarn of wholly aromatic polyester fiber with polyamide 6 and setting the ratio of the core fiber to the coating resin within a specific range, a lace can be obtained that has high tensile strength, knot strength, knot strength retention, and excellent flex resistance and abrasion resistance, all of which are required characteristics for a lace for a dial-type lacing system, and have completed the present invention. That is, the object of the present invention is to provide a lace for a dial-type lacing system, in which a core fiber made of a twisted multifilament yarn of wholly aromatic polyester fiber is resin-coated with polyamide 6, and the twist coefficient of the twisted yarn is 30 and The total fineness of the core fiber is 840 to 1670 dtex, and the diameter of the cord is 0.8 mm; The ratio of the diameter of the core fiber to the diameter of the cord is 0.43 This is achieved by a lace for a dial lacing system characterized by a flexural modulus of 0.6 or less.

[0017] The tensile strength of the string is preferably 160N or more, and more preferably 220N or more.

[0018] It is also preferable that the knot strength retention of the string is 30% or more.

[0019] Furthermore, it is preferable that the string has a tensile strength retention rate of 30% or more after the following bending resistance test. (Flexibility test) A bending resistance test is carried out under the following conditions using a bending tester (manufactured by Ichikawa Iron Works), and the tensile strength of the string is measured after the bending resistance test. The tensile strength retention rate (%) after the bending resistance test is calculated using the following formula. Tensile strength retention rate after flex test (%) = (tensile strength after flex test (N) / tensile strength before flex test (N)) × 100 Bending speed: 20 reciprocations / times Flexion angle: 90° left and right Number of flexes: 5000

[0020] It is also preferable that the lace has a breakage count of 300 or more in the abrasion resistance test described below. (Wear resistance test) The test is conducted under the following conditions using an abrasion tester (manufactured by Ichikawa Iron Works) in which a string is moved back and forth on the surface of a rotating abrasion element, while the string itself is simultaneously rotated around an axis in the length direction to cause abrasion, and the number of times until the string breaks is recorded as the number of times to break. Wear element: A metal disc with knurled diamond-shaped grooves Wear element rotation speed: 100 rpm Stroke rate: 50 strokes / min String rotation speed: 16 rpm String rotation direction: Counterclockwise [Effects of the Invention]

[0021] According to the present invention, when used as a lace for a dial-type lacing system that is subjected to various loads such as tensile load, tensile load taking into account the binding portion, bending load, and friction, it is possible to obtain a lace that not only satisfies short-term performance requirements but also can withstand repeated use over a long period of time. DETAILED DESCRIPTION OF THE INVENTION

[0022] The lace of the present invention is a lace for a dial-type lacing system, in which a core fiber made of twisted multifilament yarn of high-strength fibers is resin-coated. The resin-coating of the core fiber improves abrasion resistance, flex resistance, and knot tenacity retention. The laces of the present invention can be used as laces for dial-type lacing systems adopted in various products, such as not only shoes but also protective gloves, hats, medical prostheses, etc., as long as the product adopts a dial-type lacing system.

[0023] The core fiber in the present invention is a twisted multifilament yarn of high strength fiber.

[0024] The high strength fiber in the present invention preferably has a tensile strength of at least 160 N. If the tensile strength is at least 160 N, the fiber can withstand repeated use over a long period of time when used as a lace for a dial-type lacing system.

[0025] The high strength fiber in the present invention is preferably made of at least one type of fiber selected from wholly aromatic polyester fiber, aramid fiber, polyparaphenylene benzobisoxazole fiber, and polyphenylene sulfide fiber, and more preferably made of at least one type of fiber selected from wholly aromatic polyester fiber, aramid fiber, and polyparaphenylene benzobisoxazole fiber. It is particularly preferable that the fiber is made of wholly aromatic polyester fiber. Fully aromatic polyester fibers have high tensile strength and can withstand tensile loads when used as string. Furthermore, their high melting temperature of 300-360°C prevents deterioration of physical properties due to thermal decomposition when melt-coating with a coating resin. Furthermore, their low water content minimizes the generation of bubbles during resin coating. Excessive bubble generation leads to poor appearance, reduced physical properties, and impaired smoothness of the coating resin, making it susceptible to localized loads.

[0026] Among the high strength fibers, for example, wholly aromatic polyester fibers are formed from wholly aromatic polyester polymers.

[0027] Wholly aromatic polyester polymers are made of aromatic dicarboxylic acids, aromatic diols, and / or aromatic hydroxycarboxylic acids, or derivatives thereof, and may also include copolymers of these with alicyclic dicarboxylic acids, alicyclic diols, aliphatic diols, or derivatives thereof. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 4,4'-dicarboxydiphenyl, 2,6-dicarboxynaphthalene, 1,2-bis(4-carboxyphenoxy)ethane, etc., and their nucleus-substituted derivatives with alkyl, aryl, alkoxy, or halogen groups. Examples of aromatic diols include hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylethane, 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 2,6-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, and the like, as well as their respective nucleus-substituted derivatives with alkyl, aryl, alkoxy, and halogen groups. Examples of aromatic hydroxycarboxylic acids include p-hydroxybenzoic acid, m-hydroxybenzoic acid, 2-hydroxynaphthalene-6-carboxylic acid, 1-hydroxynaphthalene-5-carboxylic acid, and the like, as well as their respective nucleus-substituted derivatives with alkyl, aryl, alkoxy, and halogen groups. Alicyclic dicarboxylic acids include trans-1,4-dicarboxycyclohexane, cis-1,4-dicarboxycyclohexane, etc., and their alkyl, aryl, and halogen nucleus-substituted derivatives. Alicyclic and aliphatic diols include trans-1,4-dihydroxycyclohexane, cis-1,4-dihydroxycyclohexane, ethylene glycol, 1,4-butanediol, xylylenediol, etc.

[0028] Among these combinations, preferred wholly aromatic polyester polymers in the present invention include, for example, (a) copolyesters consisting of 40 to 70 mol% of p-hydroxybenzoic acid residues, 15 to 30 mol% of the above-mentioned aromatic dicarboxylic acid residues, and 15 to 30 mol% of aromatic diol residues, (b) copolyesters consisting of terephthalic acid and / or isophthalic acid and chlorohydroquinone, phenylhydroquinone, and / or hydroquinone, and (c) copolyesters consisting of 20 to 80 mol% of p-hydroxybenzoic acid residues and 20 to 80 mol% of 2-hydroxynaphthalene-6-carboxylic acid residues.

[0029] To obtain the wholly aromatic polyester polymer used in the present invention using the above starting materials, a polycondensation reaction is carried out either directly or by esterification with an aliphatic or aromatic monocarboxylic acid or a derivative thereof, an aliphatic alcohol, a phenol, or a derivative thereof. Known methods such as bulk polymerization, solution polymerization, and suspension polymerization can be used for the polycondensation reaction. The resulting polymer is then heat-treated in an inert gas or under reduced pressure either directly or in powder form to prepare a sample for spinning. Alternatively, the polymer may be granulated in an extruder before use.

[0030] The components may contain other polymers or additives (pigments, carbon, heat stabilizers, ultraviolet absorbers, lubricants, fluorescent whitening agents, etc.) to the extent that the strength of the components is not substantially reduced.

[0031] The wholly aromatic polyester polymer of the present invention has a molecular weight range suitable for spinning. The "flow onset temperature" is used as a physical property value corresponding to the molecular weight suitable for this melt spinning condition. The "flow onset temperature" is defined as the temperature at which an aromatic polyester sample flows through a nozzle with a diameter of 1 mm, a length of 10 mm, and a pressure of 100 kg / cm2 at a temperature increase of 4°C / min using a flow tester CFT-500 (manufactured by Shimadzu Corporation), and the sample has an apparent viscosity of 4,800 Pascal seconds.

[0032] In the present invention, the "flow initiation temperature" of the aromatic polyester suitable for melt spinning is preferably 305 to 325°C.

[0033] The wholly aromatic polyester fiber of the present invention may be produced by a known melt extrusion method.

[0034] The total fineness of the multifilament of the high strength fiber in the present invention must be a thickness corresponding to the lace for a dial-type lacing system, for example, 500 to 10,000 dtex.

[0035] The twist factor of the multifilament twisted yarn of high strength fiber in the present invention is preferably 5 to 80. The twist factor is calculated by the following formula. K=T×√D÷100 (Twist coefficient: K, twist number: T (turns / m), fineness: D (dtex))

[0036] The coating resin in the present invention is preferably at least one polymer selected from polyamide, fluororesin, polyurethane, polyethylene, polyvinyl alcohol, etc., and more preferably polyamide because it has high abrasion resistance, moderate stiffness, and loosens moderately when released from fastening. The polyamide is at least one polymer selected from polyamide 6, polyamide 11, polyamide 12, polyamide 66, etc., and polyamide 6 is particularly preferred.

[0037] The ratio of the diameter of the core fiber to the diameter of the cord of the present invention (hereinafter sometimes referred to as the core-sheath ratio) is 0.4 to 0.7. If the diameter ratio is within this range, it is possible to improve knot strength, knot strength retention, flex resistance, and abrasion resistance to a satisfactory level without impairing tensile strength.

[0038] The thickness of the coating resin in the present invention is preferably 0.15 mm or more, more preferably 0.2 mm or more. If the thickness of the coating resin is 0.15 mm or more, abrasion of the core fibers due to exposure of the core fibers on the surface is prevented. Furthermore, since the irregularities of the core fibers do not appear on the surface, the appearance is smooth and the local load on the coating resin is reduced. Furthermore, the appearance of the string is excellent.

[0039] The cord of the present invention may be used with a known diameter, for example, 0.5 to 5 mm, although this is not limited to the range described below.

[0040] The tensile strength of the lace of the present invention is preferably 160 N or more, and more preferably 220 N or more. If the tensile strength of the lace is 160 N or more, it can withstand the tensile load when used as a lace for a dial-type lacing system.

[0041] The knot strength retention of the lace of the present invention is preferably 30% or more. If the lace has a knot strength retention of 30% or more, it can withstand repeated use over a long period of time when used as a lace for a dial-type lacing system.

[0042] The lace of the present invention preferably has a flex resistance of 30% or more, as described below. If the result of the flex resistance test of the lace is 30% or more, the lace can withstand repeated use over a long period of time when used as a lace for a dial-type lacing system.

[0043] The lace of the present invention preferably has a result of 300 or more cycles in the abrasion resistance test described below. If the result of the abrasion resistance test of the lace is 300 or more cycles, the lace can withstand repeated use over a long period of time when used as a lace for a dial-type lacing system.

[0044] The resin coating method in the present invention is not particularly limited, and any known method may be applied, but according to the present invention, a method of coating the resin by extrusion molding is particularly preferred. In order to improve the adhesiveness between the coating resin and the core fiber, the core fiber may be coated with an adhesive resin before being coated with the resin. [Example]

[0045] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Evaluations in the examples were carried out as follows.

[0046] (Measurement of cord diameter) The diameter of the string was measured in accordance with 4.3.2 of JIS C3005:2014.

[0047] (Measurement of core fiber diameter) The diameter of the core fiber was measured in accordance with 4.3.2 of JIS C3005:2014.

[0048] (Tensile strength test) The tensile strength of the string was measured in accordance with JIS L1013:2010 8.5.

[0049] (Knot strength test) The knot strength of the string was measured in accordance with 8.6 of JIS L1013:2010.

[0050] (Nodule strength retention rate) The knot strength retention rate was calculated using the following formula. Knot strength retention rate (%) = {Knot strength (N) / Tensile strength (N)} x 100

[0051] (Flexibility test) The bending resistance was evaluated by the bending resistance test described above, in which the test conditions and evaluation method were as described above.

[0052] (Wear resistance test) The abrasion resistance was evaluated by the abrasion resistance test described above, under the same test conditions and evaluation method as described above.

[0053] (Unevenness evaluation) When the diameter of the string was measured at 100 points at 1m intervals, a variation rate of less than 3% was evaluated as ◎, a variation rate of 3% to less than 5% was evaluated as ○, and a variation rate of 5% or more was evaluated as ×.

[0054] Example 1 A single fully aromatic polyester multifilament (manufactured by KB Seiren Co., Ltd.) with a total fineness of 1670 dtex was twisted to form a core fiber with a twist factor of 30. The core fiber was melt-coated with polyamide 6 by extrusion molding to produce a cord with a diameter of 0.8 mm. The obtained string was subjected to measurement of various physical properties and evaluation of appearance.

[0055] Example 2 A string was produced in the same manner as in Example 1 except that the total fineness of the multifilaments used as the core fiber was 1100 dtex, and various physical property measurements and appearance evaluations were carried out using the obtained string.

[0056] Example 3 A string was produced in the same manner as in Example 1 except that the total fineness of the multifilaments used as the core fiber was 840 dtex, and various physical property measurements and appearance evaluations were carried out using the obtained string.

[0057] (Comparative Example 1) A string was produced in the same manner as in Example 1, except that three wholly aromatic polyester multifilaments (manufactured by KB Seiren Co., Ltd.) having a total fineness of 1100 dtex were twisted at a twist factor of 30 to form a core fiber, and various physical property measurements and appearance evaluations were carried out using the obtained string.

[0058] (Comparative Example 2) A string was produced in the same manner as in Example 1 except that the total fineness of the multifilaments used as the core fiber was 110 dtex, and various physical property measurements and appearance evaluations were carried out using the obtained string.

[0059] (Comparative Example 3) A cord was produced in the same manner as in Example 1, except that a concentric strand cable (manufactured by Nikko Rope Co., Ltd.) consisting of seven strands twisted together, each of which is made of seven 50 μm diameter stainless steel (SUS) single wires, was used as the core fiber, and various physical property measurements and appearance evaluations were carried out using the obtained cord.

[0060] Comparative Example 4 We measured various physical properties and evaluated the appearance of a concentric strand cable (manufactured by Nikko Rope Manufacturing Co., Ltd.) which is made by twisting together seven strands each made of seven 90 μm diameter SUS single wires.

[0061] (Comparative Example 5) Various physical properties and appearance of a polyamide 6 monofilament (manufactured by Unitika Ltd.) with a diameter of 0.81 mm were measured.

[0062] (Comparative Example 6) High density polyethylene (HDPE) multifilament (manufactured by Honeywell) with a total fineness of 220 dtex was used, and a 4-ply braided cord was used to measure various physical properties and evaluate the appearance. These results are also shown in Table 1.

[0063] [Table 1]

[0064] The lace of Example 1 had high tensile strength, knot strength, and knot strength retention, and was excellent in flex resistance and abrasion resistance. In addition, the unevenness evaluation was rated as ○, indicating that it was fully suitable as a lace for a dial-type lacing system.

[0065] The laces of Examples 2 and 3 had high tensile strength, knot strength, and knot strength retention, and were excellent in flex resistance and abrasion resistance. In addition, the unevenness evaluation was rated as Excellent, indicating that they were suitable as laces for dial-type lacing systems.

[0066] The lace of Comparative Example 1 had high tensile strength and knot strength, and excellent abrasion resistance. However, it had low knot strength retention, poor flex resistance, and an unevenness rating of ×. It was not suitable as a lace for a dial-type lacing system.

[0067] The lace of Comparative Example 2 also had a high knot strength retention rate and excellent flex resistance. It also received an excellent unevenness evaluation. However, it had low tensile strength and knot strength. It also had poor abrasion resistance. It was therefore not suitable as a lace for a dial-type lacing system.

[0068] The strand cables of Comparative Examples 3 and 4 had high tensile strength, knot strength, and knot strength retention, and were excellent in abrasion resistance. However, they had poor flex resistance. Furthermore, although the unevenness evaluation was rated as Excellent, unevenness was visible to the naked eye. Therefore, they were not suitable as laces for dial-type lacing systems.

[0069] The monofilament of Comparative Example 5 was evaluated as good in terms of unevenness. It also had high tensile strength, knot strength, and knot strength retention, but poor flex resistance and abrasion resistance. It was therefore not suitable as a lace for a dial-type lacing system.

[0070] The lace of Comparative Example 6 had no irregularities. It also had high knot strength, knot strength retention, and flex resistance, but low tensile strength and abrasion resistance. It was therefore unsuitable as a lace for a dial-type lacing system. [Industrial Applicability]

[0071] The lace of the present invention can be suitably used not only as a lace for a dial-type lacing system adopted in shoes, but also as a lace for a dial-type lacing system adopted in various products such as protective gloves, hats, and medical devices, and can withstand repeated use over a long period of time.

Claims

1. A lace for a dial-type lacing system, comprising a core fiber made of a twisted yarn of a multifilament of wholly aromatic polyester fiber, and the core fiber being resin-coated with polyamide 6, wherein the twisted yarn has a twist coefficient of 30, the core fiber has a total fineness of 840 to 1670 dtex, the lace has a diameter of 0.8 mm, and the ratio of the diameter of the core fiber to the diameter of the lace is 0.43 to 0.

6.

2. 2. The lace for a dial-type lacing system according to claim 1, wherein the lace has a tensile strength of 160 N or more.

3. 3. The lace for a dial-type lacing system according to claim 1, wherein the knot strength retention rate is 30% or more.

4. The lace for a dial-type lacing system according to any one of claims 1 to 3, which has a tensile strength retention rate of 30% or more after the following flex resistance test. (Flexibility test) A bending test is carried out under the following conditions using a bending tester (manufactured by Ichikawa Iron Works), and the tensile strength of the string is measured after the bending test. The tensile strength retention rate (%) after the flex resistance test is calculated using the following formula. Tensile strength retention rate after flex resistance test (%) = (tensile strength after flex resistance test (N) / tensile strength before flex resistance test (N)) × 100 Bending speed: 20 reciprocations / times Flexion angle: 90° left and right Number of bending times: 5,000

5. The lace for a dial-type lacing system according to any one of claims 1 to 4, which has a breakage count of 300 or more in the abrasion resistance test described below. (Wear resistance test) The test was conducted under the following conditions using an abrasion tester (manufactured by Ichikawa Iron Works) in which a string was moved back and forth on the surface of a rotating abrasion element, while the string itself was simultaneously rotated around its axis in the length direction to cause abrasion, and the number of times until the string broke was recorded as the number of times to break. Wear element: Metal disc with knurled diamond-shaped grooves Wear element rotation speed: 100 rpm Strokes per minute: 50 String rotation speed: 16 rpm String rotation direction: counterclockwise

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