Rubber material reinforcing synthetic fiber cord and producing method thereof

Abstract

To provide a synthetic fiber cord for reinforcing rubber materials, such as automotive hoses, that exhibits good adhesion to ethylene-α-olefin-nonconjugated diene copolymer rubber compounds (EPDM rubber), while also ensuring good processability during cord and hose manufacturing, specifically, it has low tackiness on the surface of synthetic fiber cords, excellent pull-out from wound packages, minimal adhesive detachment from the cord surface, and prevents residue from becoming sticky, thereby reducing deposition on guides and avoiding deterioration of the quality of cord- and hose-based rubber products brought into the package, furthermore, it allows the production of flexible hoses with excellent leak resistance at the crimped sections, in addition, a synthetic fiber cord for rubber material reinforcement is provided that uses a novel adhesive treatment containing no resorcinol or formalin, contributing to reduced environmental impact.SOLUTION: A synthetic fiber cord for reinforcing rubber materials, in which the synthetic fibers are treated with an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and rubber latex (C), wherein the adhesive treatment agent has a solid weight ratio of lignin (A) to blocked isocyanate compound (B) of (solid content of A):(solid content of B)=10:1 to 10:30, and the ratio of CR to PB latex in 100 pts.wt. of solid content of the rubber latex (C) is 30:70 to 80:20.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a synthetic fiber cord for reinforcing rubber materials. [Background technology]

[0002] Synthetic fibers, such as polyester fibers, polyamide fibers, and polyvinyl alcohol fibers, have physical properties such as high strength, modulus, and excellent fatigue resistance, and have traditionally been used as fiber cords to reinforce rubber materials such as automobile hoses. However, the inertness of the synthetic fiber surface itself poses a problem of poor adhesion to rubber. Furthermore, in recent years, EPDM rubber, which has excellent high-temperature properties, has been primarily used in the field of automobile hoses, but this rubber has the problem of having few double bonds in its chemical structure and therefore poor reactivity. For this reason, various methods for improving the adhesion between synthetic fiber cords and EPDM rubber have been investigated.

[0003] RFL (resorcinol-formalin-latex) adhesives, which contain resorcinol, formalin, and rubber latex, have been widely used to bond synthetic fibers to the rubber composition of rubber products. However, both resorcinol and formalin are highly toxic substances, have a high environmental impact, and are harmful to health. In recent years, there has been a demand to reduce their release into the atmosphere during use and to reduce their usage.

[0004] Furthermore, in order to ensure that the fibers adhere to rubber, it is essential to apply an adhesive such as the RFL to the fiber surface. However, during the adhesive application process, aggregates resulting from the adhesive composition applied can adhere to processing equipment such as the rollers of the dipping machine, reducing operability.

[0005] Furthermore, when multiple adhesive-treated fiber cords are pulled together and braided into a hose shape, friction between the adhesive-treated cords and guides can cause the adhesive to fall off, stick to the guides, or fly off, which can cause problems such as impaired productivity and a poor working environment.

[0006] Furthermore, automotive hoses such as brake hoses, radiator hoses, and car air conditioning hoses are used as products by crimping both ends with metal fittings. However, when such hoses are used, they suffer from thermal aging and are repeatedly exposed to heat cycles from high to low temperatures, which can lead to problems such as liquid leakage from the parts where the hose is crimped with the metal fittings.

[0007] In an attempt to solve the above problem, for example, the following Patent Documents 1 to 5 have been proposed.

[0008] Patent Document 1 discloses an adhesive composition for organic fiber cords, which contains a urethane resin having a thermally dissociable blocked isocyanate group, an epoxy compound, a polymer having an oxazoline group, a basic catalyst having a number average molecular weight of 1,000 to 75,000, and rubber latex.

[0009] Patent Document 2 discloses a processing method in which a fabric reinforcing member is immersed in a bath containing polycarboxylic acid, a base, an epoxy compound, a polyisocyanate compound, and VP latex.

[0010] Patent Document 3 discloses an aqueous adhesive composition containing a thermosetting resin having a specific functional group and an unsaturated elastomer latex.

[0011] Patent Document 4 discloses an adhesive for organic fibers that contains at least one component selected from the group consisting of polyphenols, chlorophenol resins, and lignin resins, and at least one component selected from water-soluble polymers other than the above components or water-dispersible polymers other than the above components.

[0012] Patent Document 5 discloses a polyester fiber cord for reinforcing hoses, which is made by treating polyester fibers to which a polyepoxide compound has been previously applied with a treatment agent in which RFL and chloro-modified resorcinol are mixed in a specific weight ratio. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-64037 [Patent Document 2] Special Publication No. 2020-525622 [Patent Document 3] Special Publication No. 2019-518087 [Patent Document 4] WO2018 / 003572 issue [Patent Document 5] Japanese Patent Application Laid-Open No. 2008-202182 Summary of the Invention [Problem to be solved by the invention]

[0014] However, Patent Documents 1 to 3 all contain no resorcinol or formalin, which is advantageous in reducing the environmental impact compared to conventional RFL adhesives, but they have poor adhesion to EPDM rubber. Patent Document 4 does not contain resorcinol or formalin, which is advantageous in reducing the environmental impact compared to conventional RFL adhesives, and it also exhibits a certain degree of adhesion to EPDM rubber, but this is insufficient for practical use, and its processability and liquid leakage resistance are insufficient. Patent Document 5 has improved processability and liquid leakage resistance, but uses a conventional RFL adhesive, which has the problem of a large environmental impact.

[0015] The present invention has been made as a result of studies aimed at solving the problems in the prior art described above.

[0016] Specifically, the present invention aims to provide a synthetic fiber cord for reinforcing rubber materials such as automobile hoses, which has good adhesion to ethylene-α-olefin-non-conjugated diene copolymer rubber compounds (hereinafter referred to as "EPDM rubber") and is easy to process during cord and hose production, i.e., the synthetic fiber cord has low tackiness on its surface, allowing it to be easily unwound from a winding package, with little adhesive shedding from the synthetic fiber cord surface and no sticky residue, resulting in little accumulation on guides and preventing the accumulated residue from adhering to the running cord, which would degrade the quality of the package and the final product, such as a hose, and which further enables the production of hoses with excellent flexibility and resistance to fluid leakage at the crimped portion. Another object of the present invention is to provide a synthetic fiber cord for reinforcing rubber materials, which is made from a novel adhesive treatment agent that is free of resorcinol and formalin and is advantageous in reducing environmental impact, and a method for producing the same. [Means for solving the problem]

[0017] In order to solve the above problems, the present invention employs the following means.

[0018] That is, (1) a synthetic fiber cord for reinforcing rubber materials, the synthetic fiber being treated with an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C), and the adhesive stress of the cord surface is 0.1 to 0.8 N / cm 2 A synthetic fiber cord for reinforcing rubber materials, characterized by:

[0019] (2) The synthetic fiber cord for reinforcing rubber materials according to (1), characterized in that the solid weight ratio of the lignin (A) to the blocked isocyanate compound (B) in the adhesive treatment agent is (solid content of A):(solid content of B)=10:1 to 10:30, and the ratio of CR latex to PB latex in 100 parts by weight of the solid content of the rubber latex (C) is 30:70 to 80:20.

[0020] (3) The synthetic fiber cord for reinforcing rubber materials according to either (1) or (2), characterized in that the solid content weight ratio of the lignin (A), the blocked isocyanate compound (B), and the rubber latex (C) in the adhesive treatment agent is ((solid content of A) + (solid content of B)):(solid content of C) = 10:90 to 60:40.

[0021] (4) A synthetic fiber cord for reinforcing rubber materials according to any one of (1) to (3), characterized in that the Gurley cord hardness per unit of resin attached to the cord is 1 to 10 mN / % or less, and the rate of change in Gurley cord hardness after heating is 100% to 240%.

[0022] (5) A synthetic fiber cord for reinforcing rubber materials according to any one of (1) to (4), characterized in that the synthetic fiber is treated with a pre-coating agent before being treated with the adhesive treatment agent, and the pre-coating agent is an epoxy compound with a concentration of 1 to 6%.

[0023] (6) A synthetic fiber cord for reinforcing an automobile hose, characterized in that the synthetic fiber is treated with a precoating agent before being treated with the adhesive treatment agent, and the precoating agent contains at least an epoxy compound and a blocked isocyanate compound (solids weight ratio of 10:0 to 10:30) and has a concentration of 1 to 6%.

[0024] (7) A method for producing a synthetic fiber cord for reinforcing rubber materials, comprising adhering to twisted synthetic fibers an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C), the adhesive treatment agent having a solids weight ratio of the lignin (A) to the blocked isocyanate compound (B) (solids of A):(solids of B) of 10:1 to 10:30, and a ratio of CR to PB latex in 100 parts by weight of the solids of the rubber latex (C) of 30:70 to 80:20, followed by heat treatment.

[0025] (8) The method for producing a synthetic fiber cord for reinforcing rubber materials according to (7), wherein the adhesive treatment agent has a solid content weight ratio of the lignin (A), the blocked isocyanate compound (B), and the rubber latex (C) of ((solid content of A) + (solid content of B)):(solid content of C) = 10:90 to 60:40.

[0026] (9) A method for producing a synthetic fiber cord for reinforcing rubber materials according to (7) or (8), characterized in that it comprises a step of adhering a pre-coating agent to the synthetic fiber and then heat-treating it before adhering an adhesive treatment agent to the synthetic fiber and then heat-treating it, and the pre-coating agent is an epoxy compound with a concentration of 1 to 6%.

[0027] (10) A method for producing a synthetic fiber cord for reinforcing rubber materials according to any one of (7) to (9), characterized in that it comprises a step of adhering a precoating agent to the synthetic fiber and then heat-treating it before adhering an adhesive treatment agent to the synthetic fiber and then heat-treating it, and the precoating agent contains at least an epoxy compound and a blocked isocyanate compound (solids weight ratio of 10:0 to 10:30) and has a concentration of 1 to 6%. [Effects of the Invention]

[0028] The present invention provides a synthetic fiber cord for reinforcing rubber materials that has good adhesion to ethylene-α-olefin-non-conjugated diene copolymer rubber compounds (EPDM rubbers), reduces adhesive shedding from the synthetic fiber cord surface during cord production, and prevents sticky residue, resulting in less residue buildup on guides and preventing adhesive residue from adhering to the running cord, which would degrade the quality of packaging and final products such as hoses. It also provides a synthetic fiber cord for reinforcing rubber materials that is flexible and has excellent resistance to liquid leakage at the crimped portion. Furthermore, it provides a synthetic fiber cord for reinforcing rubber materials that is made from a new adhesive treatment agent that is free of resorcinol and formalin and is advantageous in reducing the environmental impact. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a perspective view of a Gurley cord hardness measuring device. [Figure 2]FIG. 1 is a schematic diagram of a friction tester used to evaluate processability. [Figure 3] FIG. 1 is a schematic diagram of a measuring piece and a measuring device for air diffusion measurement. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be described in detail below.

[0031] The synthetic fiber cord for reinforcing rubber materials of the present invention is obtained by treating a synthetic fiber with an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C).

[0032] The synthetic fibers used in the present invention are preferably in the form of multifilaments. Materials constituting the synthetic fibers include nylon 6, nylon 66, nylon 46, polyethylene terephthalate, polyethylene naphthalate, aramid, and polyvinyl alcohol. From the standpoints of durability and industrial productivity in rubber material applications, it is particularly preferable to use at least one selected from polyester fibers, nylon fibers, and polyvinyl alcohol-based fibers.

[0033] The polyester fiber is a polyester composed of a dicarboxylic acid and a glycol, with ethylene terephthalate as the main repeating unit. Examples of dicarboxylic acid components include terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, and 1,4-cyclohexanedicarboxylic acid. Examples of glycol components include ethylene glycol, propylene glycol, tetramethylene glycol, and 1,4-cyclohexanedimethanol. A portion of the dicarboxylic acid component may be replaced with adipic acid, sebacic acid, dimer acid, or metal sulfonate-substituted isophthalic acid. Furthermore, a portion of the glycol component may be replaced with diethylene glycol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, or polyalkylene glycol. Among these, polyethylene terephthalate, in which 90 mol % or more of the dicarboxylic acid component is terephthalic acid and 90 mol % or more of the glycol component is ethylene glycol, is preferred. This polyester may contain various inorganic particles such as titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin, and zirconium acid, crosslinked polymer particles, and various metal particles, as well as conventional additives such as antioxidants, sequestering agents, ion exchange agents, color inhibitors, waxes, silicone oils, and various surfactants.

[0034] Furthermore, when used as a brake hose, the intrinsic viscosity of the fiber is preferably 0.85 or higher, and the polyester fiber is preferably one in which the maximum temperature of the main dispersion, which appears in the temperature dispersion of the loss tangent (tan δ) when measured at a frequency of 11 Hz using a dynamic viscoelasticity measuring device, is 130°C or higher, more preferably 140°C or higher. When the main dispersion of the loss tangent (tan δ) is within the above range, even when brake fluid comes into contact with the fiber, the diffusion of rust inhibitors and the like in the brake fluid into the polyester is suppressed, and a hose with little deterioration can be obtained.

[0035] The polyester fiber may be previously provided with a polyepoxide compound during the spinning process. The polyepoxide compound that can be used in the present invention includes a compound containing at least two epoxy groups in one molecule in an amount of 0.1 g equivalent or more per 100 g of the polyepoxide compound. Specific examples include reaction products of polyhydric alcohols such as pentaerythritol, ethylene glycol, polyethylene glycol, propylene glycol, glycerol, and sorbitol with halogen-containing epoxides such as epichlorohydrin; polyepoxide compounds obtained by oxidizing unsaturated compounds with peroxide or hydrogen peroxide, such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexenecarboxylate, bis(3,4-epoxy-6-methyl-cyclohexylmethyl)adipate, and aromatic polyepoxides such as phenol novolac, hydroquinone, biphenyl, bisphenol S, brominated novolac, xylene-modified novolac, phenol glyoxal, trisoxyphenylmethane, trisphenol PA, and bisphenol polyepoxides. Particularly preferred are sorbitol glycidyl ether and cresol novolac polyepoxides.

[0036] These compounds are usually used as an emulsion, but to prepare an emulsion or solution, the polyepoxide compound may be used as is, or, if necessary, dissolved in a small amount of solvent, and then emulsified or dissolved using a known emulsifier, such as sodium alkylbenzenesulfonate, dioctyl sulfosuccinate sodium salt, or nonylphenol ethylene oxide adduct.

[0037] A method for applying a polyepoxide compound during the spinning process of polyester fibers is usually to apply it together with a spinning oil during the spinning process of polyester fibers. The amount of the polyepoxide compound attached is usually in the range of 0.1 to 5 wt %. If the amount of the polyepoxide compound attached is less than 0.1 wt %, the effect of the polyepoxide compound is not fully exerted, and satisfactory adhesion between the polyester fiber and the ethylene-propylene rubber may not be obtained. On the other hand, if the amount of the polyepoxide compound attached exceeds 5 wt %, the fiber becomes very hard, which may make it difficult to apply the compound during the spinning process. In addition, the penetration of treatment agents used in subsequent processes may be reduced, which may result in reduced adhesive performance, which is undesirable.

[0038] The polyamide fiber is a multifilament made of aliphatic polyamide. Specific examples of aliphatic polyamide include poly-ε-caprolactam (nylon 6) and polyhexamethylene adipamide (nylon 66). In the present invention, nylon 66 fiber containing 95 mol % or more of hexamethylene adipamide repeating units is preferably used in terms of strength and heat resistance.

[0039] Aliphatic polyamides may also be copolymers of polyamides containing copolymerizing components to the extent that the effects of the present invention are not impaired. Furthermore, polyamides to which copolymerizing components or other particles such as pigments have been added may also be used to improve spinnability and the quality of the final product. Specific copolymerizing components include ε-caprolactam, tetramethylene adipamide, hexamethylene sebacamide, hexamethylene isophthalamide, tetramethylene terephthalamide, and xylylene phthalamide. Polyamides may also contain various inorganic particles such as titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin, and zirconium acid, as well as crosslinked polymer particles and various metal particles. Conventional additives such as dyes, weathering agents, heat resistance agents, antioxidants, and antioxidants may also be added.

[0040] When used as a reinforcing cord for an automobile hose, a polymer with a high degree of polymerization is used to obtain a fiber with high strength and toughness, and the fiber preferably has a relative viscosity in sulfuric acid of 3 to 4.5.

[0041] The polyvinyl alcohol fiber is a fiber obtained by spinning and stretching a vinyl alcohol polymer, preferably having a degree of saponification of 90 mol% or more, by a dry, wet, or dry-wet method, which is made of a polymer containing vinyl alcohol as the main repeating unit. The strength is preferably 7 cN / dtex or more, more preferably 7.5 cN / dtex or more, and the elongation at break is preferably less than 11%, more preferably less than 9%. If the strength is less than 7 cN / dtex, the pressure resistance of the resulting hose may be insufficient for use in reinforcing an automobile hose, while if the elongation at break exceeds 11%, the expansion resistance required for automobile hose applications may be impaired.

[0042] The synthetic fibers used in the present invention are not subject to restrictions on fineness, number of filaments, cross-sectional shape, etc., but typically have a total fineness of 200 to 5,000 dtex, 30 to 1,000 filaments, and a circular cross-section yarn, with a total fineness of 250 to 3,000 dtex, 50 to 500 filaments, and a circular cross-section yarn being preferred. If the total fineness is less than 200 dtex, the cord strength may be insufficient, and if it exceeds 5,000 dtex, the cord may become too thick and handleability may decrease. Furthermore, if it is less than 30 filaments, the cord may become too stiff and handleability may decrease, and if it exceeds 500 filaments, the cord may become too fluffed and quality may decrease.

[0043] The synthetic fiber cord for reinforcing rubber materials of the present invention is obtained by twisting one or more strands of the above synthetic fiber together to form a single-twisted cord, and then dipping the single-twisted cord in an adhesive treatment agent and heat treating it to obtain a dipped cord. The twist number of the cord is preferably such that the twist coefficient, defined by the following formula, is in the range of 80 to 800, more preferably 130 to 750. Twist coefficient = {number of twists (t / 10cm) × (total fineness denier)} 1 / 2} A twist factor of less than 80 can lead to a decrease in adhesive strength and deterioration of leakage resistance. A twist factor of more than 800 can reduce the strength of the cord and cause snarling (a phenomenon in which the twisted cord is partially twisted and loses its shape stability). Furthermore, when multiple single-twisted cords are further aligned and second-twisted to form a two-ply cord, as in tire cords, this is undesirable because it reduces strength and worsens leakage resistance.

[0044] The synthetic fiber cord for rubber material reinforcement of the present invention is obtained by treating a synthetic fiber with an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C). The term "treated" refers to the state of the adhesive treatment agent after it has been applied to the synthetic fiber and then subjected to a drying or heat treatment. During the drying or heat treatment, for example, volatile components contained in the adhesive treatment agent, such as a solvent such as water, are evaporated, and the blocking agent of the blocked isocyanate is removed, causing a reaction by the isocyanate group. In other words, the synthetic fiber treated with the adhesive treatment agent is in a state in which the solid components in the adhesive treatment agent are attached or bonded to the synthetic fiber without being chemically modified or unmodified. The synthetic fiber tire cord of the present invention is obtained by applying an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C) to the synthetic fiber in the same bath (single bath).

[0045] The lignin (A) used in the present invention is an aromatic polymer present in trees and is known as a natural polymeric compound having a phenylpropane skeleton as its basic structure. Lignin (A) includes not only naturally occurring lignin but also chemically treated lignin. Examples of such lignin include kraft lignin obtained from kraft pulp waste liquor and lignosulfonic acid obtained from sulfite pulp waste liquor in the papermaking industry, which uses wood as a raw material. Lignin sulfonic acid is lignin in which a sulfonic acid group has been introduced into the side chain of the phenylpropane structure of lignin. Examples of lignosulfonates include sodium lignosulfonate, magnesium lignosulfonate, and calcium lignosulfonate. In the present invention, these can be used alone or in combination, but sodium lignosulfonate is most preferred from the standpoint of adhesive strength. The lignin (A) used in the present invention preferably has a number average molecular weight of 10,000 to 60,000 and a weight average molecular weight of 80,000 to 130,000, and more preferably has a number average molecular weight of 20,000 to 50,000 and a weight average molecular weight of 90,000 to 120,000. If the number average molecular weight and weight average molecular weight of the lignin are outside these ranges, the adhesive strength and fatigue resistance as a hose may be insufficient, and therefore it is preferable to select a lignin within these ranges.

[0046] The blocked isocyanate compound (B) used in the present invention is a compound that can liberate a blocking agent upon heating to generate an active isocyanate compound, and specific examples include reaction products of polyisocyanate compounds such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and triphenylmethane triisocyanate with blocking agents such as phenols such as phenol, cresol, and resorcinol, lactams such as ε-caprolactam and valerolactam, and oximes such as acetoxime, methyl ethyl ketoxime, and cyclohexane oxime.

[0047] Among these blocked polyisocyanate compounds, aromatic polyisocyanate compounds in which diphenylmethane diisocyanate is blocked with ε-caprolactam or methyl ethyl ketoxime give particularly good results.

[0048] The blocked isocyanate compound (B) preferably has a dissociation temperature of the blocking agent of 100 to 160°C from the viewpoint of improving adhesive strength.

[0049] Examples of the rubber latex (C) that can be used in the present invention include natural rubber latex, butadiene rubber latex, styrene-butadiene rubber latex, vinylpyridine-styrene-butadiene rubber latex, nitrile rubber latex, hydrogenated nitrile rubber latex, chloroprene rubber latex, chlorosulfonated rubber latex, and ethylene-propylene-diene rubber latex, and these can be used alone or in combination.

[0050] Among these, it is preferable to contain butadiene rubber latex (PB latex) from the viewpoint of improving adhesion to EPDM rubber, while it is preferable to contain chloroprene rubber latex (CR latex) to reduce the stickiness of residue, and the ratio (weight ratio) of CR to PB latex per 100 parts by weight of the solid content of rubber latex (C) is preferably in the range of 30:70 to 80:20. By keeping the ratio of CR latex to PB latex within the above range, the adhesive stress on the cord surface can be effectively set to 0.1 to 0.8 N / cm2.

[0051] In addition to the above (A), (B), and (C), the adhesive treatment agent that can be used in the present invention may contain surfactants, antifoaming agents, vulcanization regulators, antioxidants, and pH adjusters, as needed, within limits that do not impair the objects and effects of the present invention.

[0052] In the adhesive treatment agent used in the present invention, the solid content of lignin (A) in 100% by weight of the total solid content is preferably 5 to 50% by weight, more preferably 10 to 40% by weight. If it is less than 5% by weight or exceeds 50% by weight, the adhesive strength may be insufficient.

[0053] The weight ratio of the lignin (A) to the blocked isocyanate compound (B) (solid content of A):(solid content of B) is preferably 10:1 to 10:30, and more preferably 10:5 to 10:20. If the amount of the blocked isocyanate compound is too small and exceeds this weight ratio, the adhesive strength may be insufficient, whereas if the amount of the blocked isocyanate compound is too large and exceeds this weight ratio, the cord may become too hard, and the fatigue resistance of the hose may deteriorate.

[0054] Furthermore, the lignin (A), the blocked isocyanate compound (B), and the rubber latex (C) are preferably mixed in a weight ratio of ((solid content of A) + (solid content of B)):(solid content of C) of 10:90 to 60:40. More preferably, the weight ratio of ((solid content of A) + (solid content of B)):(solid content of C) is 20:80 to 50:50. Outside this range, the adhesive strength may be insufficient, and the fatigue resistance of the hose may deteriorate.

[0055] The adhesive treatment agent used in the present invention must contain the lignin (A), blocked isocyanate compound (B), and rubber latex (C) in the same treatment agent, and the solids weight ratio of the lignin (A) to the blocked isocyanate compound (B) must be within a specified range. By containing them in the same treatment agent and ensuring that the ratio is within the specified range of the present invention, a cord can be obtained that has excellent adhesion between the EPDM rubber and the fiber, good processability, and excellent resistance to liquid leakage.

[0056] The adhesive stress on the cord surface of the synthetic fiber cord for reinforcing an automobile hose of the present invention is 0.1 to 0.8 N / cm 2 It is necessary that the strength is 0.3 to 0.6 N / cm. 2The adhesive stress on the cord surface reduces resistance when the cord is pulled out from the winding package, stabilizing tension and reducing friction with guides in the cord and hose manufacturing process, thereby reducing the generation of debris. In addition, the low adhesiveness of any debris that does adhere prevents it from adhering to the cord and being carried into the package, leading to improved quality in the manufacture of rubber products such as cords and hoses. It also contributes to improved productivity, such as easier cleaning in each process.

[0057] Furthermore, the adhesive treatment agent used in the present invention preferably has a dried film having a maximum strength of 0.2 to 1.6 MPa and a maximum elongation of 2 to 120%. The dried film preferably has a maximum strength of 0.3 to 1.4 MPa and a maximum elongation of 4 to 100%. If the maximum strength is less than 0.2 MPa, the adhesive strength may be insufficient, and if it exceeds 1.6 MPa, the fatigue resistance of the hose may deteriorate. If the maximum elongation is less than 2%, the fatigue resistance may deteriorate, and if it exceeds 120%, the adhesive strength may be insufficient. The method for preparing the dried film and the method for measuring the maximum strength and maximum elongation are as described in the Examples section.

[0058] The maximum strength and maximum elongation of the dried film of the adhesive treatment agent can be adjusted by the type of agent contained in the adhesive treatment agent and the mixing ratio. For example, the maximum strength can be adjusted to be high by increasing the amount of blocked isocyanate compound (B) mixed in the adhesive treatment agent. Also, for example, the maximum elongation can be adjusted to be high by mixing rubber latex with the adhesive treatment agent and increasing the amount of rubber latex mixed in.

[0059] The synthetic fiber cord for reinforcing rubber materials of the present invention preferably has a Gurley cord hardness per unit of resin attached to the cord of 1 to 10 mN / % or less, and a Gurley cord hardness change rate after heating of 100 to 240%. More preferably, the Gurley cord hardness is 2 to 9 mN / % and a Gurley cord hardness change rate after heating of 110 to 220%. By achieving these ranges, the rubber-cord composite can improve the cord's ability to conform to the rubber, resulting in good adhesive strength and liquid leakage resistance. There are no particular limitations on the method for adjusting the Gurley cord hardness; for example, reducing the amount of resin attached can reduce the Gurley cord hardness, while increasing the amount of resin attached can improve the Gurley cord hardness. Furthermore, during the heat treatment in the dipping step described below, the Gurley cord hardness can be reduced by reducing the heat treatment temperature and / or heat treatment time, and can be improved by increasing the heat treatment temperature and / or heat treatment time. This can also be achieved by setting the tension in the mechanical softening process after passing through the normalizing zone in the dipping process described below to 0.5 cN to 5.0 cN / dtex.

[0060] The adhesive treatment agent used in the present invention is a solid content dissolved or dispersed in water, and the total solid content concentration is preferably 10 to 20 wt%, more preferably 11 to 19 wt%. Outside this range, a sufficient amount of solid content may not be applied to the fibers, or cohesive failure may occur in the adhesive solid content, which may result in a decrease in adhesive strength.

[0061] The amount of the adhesive treatment agent attached to the synthetic fiber is preferably 0.3 to 10 parts by weight, more preferably 0.6 to 5 parts by weight, in terms of solid content, per 100 parts by weight of synthetic fiber. If the amount attached is too small, the adhesive strength may decrease, while if it is too large, the processability may deteriorate, such as by increasing the amount of residue.

[0062] The synthetic fiber cord for automobile hose reinforcement of the present invention may be treated with a precoat agent before the synthetic fiber is treated with the adhesive treatment agent (adhesive treatment agent containing at least lignin, a blocked isocyanate compound, and rubber latex).

[0063] The precoating agent preferably contains at least an epoxy compound and a blocked isocyanate compound (solids weight ratio of 10:0 to 10:30), with a concentration of 1 to 6%. Outside this range, adhesive strength may decrease. Furthermore, the amount of precoating agent adhered to the synthetic fiber is preferably 0.1 to 3 parts by weight of solids of the precoating agent per 100 parts by weight of synthetic fiber. Outside this range, adhesive strength may decrease.

[0064] The synthetic fiber cord for reinforcing rubber materials of the present invention, characterized as described above, does not contain resorcinol or formalin and is made of a new adhesive treatment agent that is advantageous in reducing the environmental impact. It has good adhesion to ethylene-α-olefin-non-conjugated diene copolymer rubber compounds (EPDM rubber), and it reduces processability during hose manufacturing (removal of adhesive from the synthetic fiber cord surface, ease of removal due to reduced adhesion between cords, and frictional resistance with various guides). It also makes it possible to provide a hose that is flexible and has excellent resistance to liquid leakage at the crimped parts.

[0065] Next, the method for producing a synthetic fiber cord for reinforcing rubber materials according to the present invention will be described using a specific example.

[0066] There are no particular limitations on the synthetic fibers used as raw materials, and it is possible to use synthetic fibers that are known for industrial use, but it is particularly preferable to use fibers that are high in strength, elasticity, and dimensional stability.

[0067] When the synthetic fiber is a polyester fiber, polyethylene terephthalate chips with an intrinsic viscosity (IV) of 1.00 to 1.50, preferably 1.20 to 1.50, are melt-spun at a spinning temperature of 285 to 300°C using an extruder-type spinning machine. After spinning, an oiling agent is applied using an oiling roller. The spinning speed is 2200 to 2800 m / min, and the multistage hot drawing is performed at a draw ratio of 2.1 to 2.4 times. After relaxation of 1.0 to 4.0%, the polyester fiber is wound up to obtain a polyester fiber. The fineness and single filament fineness of the polyester fiber are adjusted by changing the number of holes in the spinneret and the output rate. The hot drawing of the polyester fiber is performed by winding the yarn around a heated roll at 80 to 250°C.

[0068] When the synthetic fiber is a polyamide fiber, polyhexamethylene adipamide chips having a sulfuric acid relative viscosity (ηr) of 3.0 to 4.5, preferably 3.5 to 4.0, are melt-spun at a spinning temperature of 285 to 300°C using an extruder-type spinning machine. The spun yarn is passed through a heating cylinder atmosphere at 280 to 320°C located directly below the spinneret, and then cooled and solidified by blowing cold air. An oil is then applied, and the yarn is taken up on a take-up roll. The yarn taken up at a take-up speed of 300 to 1000 m / min is usually continuously drawn. The drawing is performed by winding the yarn around Nelson-type rolls with different speeds. In a preferred drawing process, the taken-up yarn is stretched by less than 10%, followed by multi-stage drawing. It is preferable that the first stage of drawing is cold drawing, and the second and subsequent stages of drawing are hot drawing, with a draw ratio of 4.0 to 6.0 times and a drawing roll temperature of 100 to 250°C during hot drawing. When producing polyamide fibers of 9 cN / dtex or more, multi-stage drawing of three or more stages is advantageous. The hot-drawn yarn is then relaxed by 2 to 12% between relaxation rolls and then wound up to obtain polyamide fibers. The fineness and single yarn fineness of the polyamide fiber are adjusted by changing the number of holes in the spinneret and the output rate.

[0069] One strand of the synthetic fiber obtained as described above is twisted to have a twist coefficient as defined above preferably in the range of 80 to 800 to form a single-twist twisted cord.

[0070] The method for producing a synthetic fiber cord for reinforcing an automobile hose of the present invention involves applying an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C) to a twisted cord in the same bath, with the adhesive treatment agent having a weight ratio of (solid content of A):(solid content of B) of 10:1 to 10:30, followed by heat treatment. Here, the weight ratio of (solid content of A):(solid content of B) is more preferably 10:5 to 10:20. If the amount of the blocked isocyanate compound is too small and exceeds this weight ratio, the adhesive strength may be insufficient. If the amount of the blocked isocyanate compound is too large and exceeds this weight ratio, the cord may become stiff, which may deteriorate the fatigue resistance of the hose.

[0071] Here, the method of applying the adhesive and heat treating is preferably a method of dipping the twisted cord in an adhesive treatment agent in a dip bath, followed by drying the water at a temperature of preferably 100 to 150° C., and then heat treating at 200 to 255° C. The preferred embodiments of the lignin (A), blocked isocyanate compound (B), and rubber latex (C) are those described above.

[0072] Here, "dipping" refers to applying an adhesive treatment agent to a twisted yarn cord by running the twisted yarn cord through a dipping tank equipped with rollers and filled with the adhesive treatment agent. "Heat treatment" refers to heating the twisted yarn cord or raw material by running the twisted yarn cord or raw material through an oven equipped with rollers and capable of being set to a predetermined temperature. Dipping machines for carrying out such dipping and heat treatment are commercially available, for example, from Ritzler. In addition to dipping, any other method for attaching the adhesive treatment agent to synthetic fibers can be used, such as spraying the adhesive treatment agent from a nozzle.

[0073] In order to control the amount of solids of the adhesive treatment agent attached to the synthetic fibers, means such as squeezing with a pressure roller, scraping with a scraper, blowing with air, and suction may be used.

[0074] Furthermore, during the mechanical softening process after the above drying and heat treatment, the synthetic fiber cord can be brought into sliding contact with the edge to perform softening treatment to obtain any desired cord stiffness.

[0075] The adhesive treatment agent used in the method of the present invention for producing a synthetic fiber cord for reinforcing rubber materials preferably has a dry film strength of 0.2 to 1.6 MPa at maximum point and a dry film elongation of 2 to 120% at maximum point.

[0076] Furthermore, the lignin (A), the blocked isocyanate compound (B), and the rubber latex (C) are preferably mixed in a weight ratio of ((solid content of A) + (solid content of B)):(solid content of C) of 10:90 to 60:40. More preferably, the weight ratio of ((solid content of A) + (solid content of B)):(solid content of C) is 20:80 to 50:50. Outside this range, the adhesive strength may be insufficient, and the fatigue resistance of the hose may deteriorate.

[0077] In the method of the present invention for producing a synthetic fiber cord for reinforcing rubber materials, a precoat agent may be applied to the synthetic fiber and heat-treated before the adhesive treatment agent (an adhesive treatment agent containing at least lignin, a blocked isocyanate compound, and rubber latex) is applied to the synthetic fiber and heat-treated.

[0078] The precoating agent preferably contains at least an epoxy compound and a blocked isocyanate compound (solids weight ratio of 10:0 to 10:30) at a concentration of 1 to 6%. Outside this range, adhesive strength may decrease. Furthermore, the amount of precoating agent adhered to the polyester fiber is preferably 0.1 to 3 parts by weight of solids of the precoating agent per 100 parts by weight of synthetic fiber. Outside this range, adhesive strength may decrease.

[0079] When applying the pre-coating agent, the same dipping method as the above method can be used. That is, a preferred method is to dip a twisted cord of polyester fiber into the pre-coating agent in a dip bath, subsequently dry the water at a temperature of preferably 100 to 150°C, and then perform a heat treatment at 200 to 255°C. The same methods as those described above can be used to control the amount of solids applied and for softening treatment.

[0080] In the manufacturing method of the present invention, an adhesive treatment agent (containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C), and used in the same bath) is applied to synthetic fibers and then heat-treated. This heat treatment is preferably performed in two stages: hot treatment and normalizing treatment. The heat treatment temperature for both is preferably 200 to 255°C. Furthermore, the tension during the hot treatment (hot stretch tension) is preferably 0.3 to 2.5 cN / dtex, and the tension during the normalizing treatment (normalizing tension) is preferably 0.1 to 1.5 cN / dtex. If the hot stretch tension is outside this range, the adhesive may be unevenly distributed on the surface of the cord, resulting in poor processability and reduced adhesive strength. If the normalizing tension is outside this range, the cord may experience increased thermal shrinkage, reducing its ability to conform to the rubber, and thus reducing leakage resistance.

[0081] The synthetic fiber cord for reinforcing rubber materials obtained in this manner is free of resorcinol and formalin and is made of a new adhesive treatment agent that is advantageous in reducing the environmental load. It has good adhesion to ethylene-α-olefin-non-conjugated diene copolymer rubber compounds (EPDM rubbers). Furthermore, there is little loss of adhesive from the surface of the synthetic fiber cord during cord production. Furthermore, because the residue does not become sticky, there is little residue buildup on guides. This prevents sticky residue from adhering to the running cord, which would otherwise degrade the quality of the packaging and the final products, such as hoses. Furthermore, because the synthetic fiber cord is flexible and has excellent resistance to fluid leakage at the crimped portions, it is suitable for use as an automotive hose. It is also applicable to rubber belts, chafers, tires, and other applications. [Example]

[0082] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples specifically described below, the measured values ​​were determined by the following methods.

[0083] (1) Amount of adhesive applied The amount of adhesive attached was determined according to the dip pick-up mass method of JIS L1017 (2002).

[0084] (2) Peel adhesion The cord was wrapped around an aluminum plate without any gaps, and unvulcanized EPDM rubber was attached to both sides of the aluminum plate. The plate was then press-vulcanized at 150°C for 30 minutes. The thickness of the rubber was 3mm, and the surface pressure between the rubber and the fiber cord was 30kgf / cm. 2 The pressing pressure was adjusted so that the force was such that the pressure was within the range of 1 / 2000. The size of the aluminum plate and the area around which the fiber cord is wrapped can be chosen as desired, and the tension during wrapping should be such that the cord does not slacken. After cooling, the fiber cord was peeled from the rubber at a speed of 50 mm / min in a 20°C environment, while maintaining a 90° angle between the rubber and the fiber cord. The peel force was expressed in N / 2.54 cm. The composition of the EPDM unvulcanized rubber is as follows: EPDM: 100 (parts by weight) HAF carbon black: 80 (parts by weight) Process oil (paraffinic): 40 (parts by weight) Zinc oxide: 5 (parts by weight) Stearic acid: 5 (parts by weight) Sulfur: 5 (parts by weight) Vulcanization accelerator: 3 (parts by weight) Zinc oxide: 5 (parts by weight).

[0085] (3) Gurley cord hardness per unit of resin attached to the cord A 1 m length of cord was cut, a metal hook was tied to one end, and a 300 g weight was tied to the other end. The cord was then hung vertically in the air for 24 hours in an environment regulated at a temperature of 25°C and a relative humidity of 40%, and a measurement sample was obtained.

[0086] This was cut into 38.1 mm (1.5 inches) test pieces, and the Gurley cord hardness was measured using a Gurley's stiffness tester manufactured by Yasuda Seiki Co., Ltd. Figure 1 shows a perspective view of the Gurley's stiffness tester.

[0087] The test specimen mounting and measurement method is as follows: (a) Fix chuck 1 in the desired position according to the length of the specimen, and then mount test specimen 2. (b) At the bottom of rotating rod 3 (below the bearing), there are load setting holes located 25.4 mm (1 inch) (W1 in Figure 1), 50.8 mm (2 inches) (W2 in Figure 1), and 101.6 mm (4 inches) (W3 in Figure 1) from the shaft. The load weight and hole position must be set according to the flexibility of test specimen 2. In this case, the load and hole position must be selected so that needle 5 on scale plate 4 points to numbers 2 through 4. (c) Once the appropriate setting for test specimen 2 is achieved, press the drive button to move the drive shaft left and right, and read the value on scale plate 4 where the needle points to within 0.1 increments. (d) For each test specimen 2, measure once left and right, for a total of 10 test specimens, and calculate the average value for one sample. The calculation method is as follows: The average value of each measurement was calculated using the following formula. Finally, the Gurley cord hardness (mg) was converted to (mN), and the value obtained by dividing it by the amount of resin attached (%) was defined as the Gurley cord hardness per unit of resin attached to the cord (mN / %).

[0088] Gurley cord hardness (mg) = R x {(W1 x 1) + (W2 x 2) + (W3 x 4)} / 5 x (L - 12.7) 2 / W×19.8 however, R: Average value of the measured values W1: Load applied to the 25.4mm load position (hole) (unit: g) W2: Load applied to the 50.8mm load position (hole) (unit: g) W3: Load applied to the 101.6mm load position (hole) (unit: g) L: Sample length (mm) W: Width of test piece (code gauge) (mm).

[0089] (4) Change in hardness of Gurley cord after heating (change after heating) A cord was cut to a length of 1 m, a metal hook was tied to one end, a 300 g weight was tied to the other end, and the cord was heated by hanging it vertically in the air for 2 hours in an environment controlled at a temperature of 160°C. Thereafter, the Gurley cord hardness was determined in the same manner as in (3) above. The value in (4) was divided by the value in (3) to obtain the rate of change (%) in the Gurley cord hardness after heating.

[0090] (5) Process passability The cord was run through a friction tester manufactured by Toray Engineering Co., Ltd., as shown in Figure 2, and the state of adhesion of the adhesive treatment agent to the guides was used as an index. A cord was removed from the fiber cord sample 6 for measurement, passed through yarn feed nip rolls 7, and under load 8, partially wrapped around the surface of a matte chrome-plated tube 9, and run. It was then taken up through yarn feed nip rolls 110, and the state of adhesion of the adhesive treatment agent to the yarn feed nip rolls 7 and 10 was confirmed. Extremely little residue was graded S, very little residue was graded A, and a large amount of residue was graded B. In the present invention, S and A were considered acceptable grades for processability, meaning they were suitable for practical use, with S being superior in practical use.

[0091] (6) Determining the characteristics of the residue In the evaluation of the processability described above, the properties of the residue were judged visually and by touch, with powdery residue being rated as "good," slightly moist powdery residue being rated as "fair," and sticky lumps being rated as "poor."

[0092] (7) Air Diffusion Value The air diffusion value was measured as an index of the hose's resistance to liquid leakage. Figure 3 shows an outline of the measurement piece and measuring device. A polyester fiber cord used to reinforce an automobile hose was placed between two rubber plates (EPDM rubber used in measuring the peel adhesion strength in (2)) so that the two cords crossed each other, and the hose was heated at 160°C for 30 minutes at 50 kgf / cm. 2 The test piece was press-vulcanized to prepare a test piece with a 5 cm length of cord sandwiched between rubber. The test piece was left in an air-circulating dry heat oven set to 100°C for one week, removed, and allowed to cool to room temperature. A constant air pressure was applied to one end of the test piece, where the cord end face was exposed, and a φ6 mm U-shaped tube filled with water was connected to the other end so that the air permeability through the cord could be calculated from the change in height of the water column. The air pressure was set to 0.2 MPa, and the distance (mm) the water surface moved after leaving the test piece for 10 minutes was measured and used as the air diffusion value. The smaller the value, the less liquid leakage there was when the test piece was made into a hose, contributing to better hose durability.

[0093] (8) Adhesion stress A "Tackiness Checker" HTC-1 manufactured by Toyo Seiki Seisakusho was used. First, a cord cut to 10 mm was attached in a single direction to the contact surface (10 × 15 mm) of the contact terminal of the evaluation device at a density of 20 cords / cm. A sample plate was then prepared using a PVC resin board (70 mm (length) × 30 mm (width) × 2 mm (thickness)). The cord, under a load of 500 g, was wrapped around the PVC resin board in the 30 mm direction at the same density (20 cords / cm) as the cord attached to the contact terminal, and both ends of the cord were fixed. The sample plate and the contact terminal were pressed against each other on a flat plate so that the cord wrapped around the sample plate and the cord arranged on the contact terminal were perpendicular to each other. After applying a 10 N load to the contact terminal for 6 seconds, the stress at the time of peeling was measured, and the value divided by the area of ​​the contact terminal was used to obtain the adhesive stress (N / cm). 2 ) was decided.

[0094] (Examples 1 to 5, 7 to 11, Comparative Examples 1 to 3) Glycerol polyglycidyl ether ("Denacol" EX313 (manufactured by Nagase Chemicals)) was diluted with water to obtain a precoat agent (A) with a total solid content of 1.0% by weight.

[0095] Furthermore, lignin (A), blocked isocyanate compound (B), and rubber latex (rubber latex (i) and (ii)) (C) were mixed with water so that the solid content ratios thereof were as shown in Table 1. During mixing, 1.5 parts of surfactant (D) was added per 100 parts of the dispersion of latex (C), and adhesive treatment agents were prepared in which the total solid content concentration was adjusted to the resin adhesion amount described in the examples. The resin adhesion amount of all precoat agents was adjusted to 0.1% by weight.

[0096] One 1100 dtex polyester multifilament yarn (Toray Industries, Inc., "Tetoron" 1100T-240-705M) was twisted to the twist coefficient shown in Table 1 to obtain a twisted yarn cord having a single twist structure.

[0097] The twisted yarn cord was immersed in the precoat agent (A) using a Computreator processor (manufactured by Ritzler Co., Ltd.), then dried at 120°C for 2 minutes, and subsequently heat-treated at 245°C for 1 minute. Subsequently, the twisted yarn cord was immersed in an adhesive treatment agent containing the components (A), (B), (C), and (D), then dried at 120°C for 2 minutes, and subsequently heat-treated at 240°C for 0.5 minutes (hot treatment), and then heat-treated at 240°C for 0.5 minutes (normalization treatment). The tension during the second bath hot treatment (hot stretch tension) and the tension during the second bath normalization treatment (normalizing tension) were the dip tensions shown in Table 1.

[0098] The adhesive solid content of the obtained polyester fiber cord for automobile hose reinforcement was 0.1 part by weight of the precoating agent relative to 100 parts by weight of the polyester fiber, and the resin content of the adhesive treatment agent containing (A), (B), (C), and (D) relative to 100 parts by weight of the polyester fiber was as shown in Table 1.

[0099] The components of the adhesive treatment agent shown in Table 1 are as follows: (A)-1: Lignin (manufactured by Tokyo Chemical Industry Co., Ltd., sodium lignosulfonate) (B)-1: Blocked isocyanate (Meisei Chemical Industry Co., Ltd., DM-6400, dissociation temperature 120 to 160°C) (C)-1: VP Latex (Nippon A&L Co., Ltd., "Pilatex") (C)-2: PB latex (manufactured by Zeon Corporation, "Nipol" LX111A) (C)-3: CR latex (Showa Denko K.K., "Shopren 400") (D)-1: Anionic surfactant (Sanyo Chemical Industries, Ltd., "Sanded ED") Example 6 Treatment and evaluation were carried out in the same manner as in Example 1, except that the precoating agent was changed to precoating agent (A) with a total solids content of 1.0 wt%, obtained by mixing glycerol polyglycidyl ether ("Denacol" EX313, manufactured by Nagase Chemical Industries, Ltd.) and a blocked isocyanate compound (DM-6400, manufactured by Meisei Chemical Industries, Ltd.) so that the solids ratio was 8:2, and diluting with water. The obtained polyester fiber tire cord had an adhesive solids adhesion amount of 0.1 part by weight for the precoating agent relative to 100 parts by weight of the polyester fiber, and 2.0 parts by weight for the adhesive treatment agent containing (A), (B), (C), and (D) relative to 100 parts by weight of the polyester fiber.

[0100] (Conventional example) The same procedures as in Example 1 were used for processing and evaluation, except that the adhesive treatment agent containing (A), (B), and (C) in Example 1 was replaced with an RFL adhesive obtained by the following procedure. Resorcinol / formalin were mixed in a molar ratio of 1 / 1.5 in the presence of caustic soda, adjusted to a solids concentration of 10%, and aged for two hours to obtain a precondensation product of resorcinol and formalin. Next, this precondensation product (RF) was mixed with rubber latex (a 1:1 mixture of VP latex (Pyratex, manufactured by Nippon A&L Co., Ltd.) and PB latex ("Nippol" LX-111A, manufactured by Nippon Zeon Co., Ltd.) by solids weight ratio) in a ratio of RF / L = 1 / 5 (solids weight ratio) and aged for 24 hours. This mixture was diluted with water to obtain an RFL adhesive with a solids weight of 15%. The solid adhesive deposition amounts of the obtained polyester fiber tire cord were 0.1 parts by weight of the precoating agent per 100 parts by weight of the polyester fiber and 2.0 parts by weight of the RFL adhesive per 100 parts by weight of the polyester fiber.

[0101] [Table 1]

[0102] The fiber cord for reinforcing rubber materials obtained as described above was measured for Gurley cord hardness, the rate of change in Gurley cord hardness after heating, and processability. Furthermore, after embedding the cord in unvulcanized rubber and vulcanizing the cord, the peel adhesion strength and air diffusion value were measured. The results are shown in Table 1.

[0103] As can be seen from the results in Table 1, in the case of Examples 1 to 9 according to the present invention, the adhesive treatment agent does not contain resorcinol or formalin, which is advantageous in reducing the environmental load compared to the conventional RFL example, and also shows good adhesion to ethylene-α-olefin-non-conjugated diene copolymer rubber compounds (EPDM rubber), good processability, flexibility, and excellent liquid leakage resistance at the crimped portion. [Explanation of symbols]

[0104] 1 chuck 2 test specimens 3 Rotating rod 4 Scale plate 5 needles W1 Load setting hole (25.4 mm (1 inch) from the axis) W2 Load setting hole (50.8 mm (2 inches) from the shaft) W3 Load setting hole (101.6 mm (4 inches) from the shaft) 6. Textile cord sample for measurement 7. Nip roll for yarn feeding 8 Load 9. Matte chrome plated pipe 10. Nip roll for yarn feeding

Claims

1. A polyester fiber cord for reinforcing an automobile hose, the synthetic fiber being treated with an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and rubber latex (C), and the adhesive stress of the cord surface is 0.1 to 0.8 N / cm ２ A synthetic fiber cord for reinforcing rubber materials, characterized by:

2. 2. The synthetic fiber cord for reinforcing rubber materials according to claim 1, wherein the adhesive treatment agent has a solids weight ratio of the lignin (A) to the blocked isocyanate compound (B) (solids content of A):(solids content of B) of 10:1 to 10:30, and a ratio of CR latex to PB latex in 100 parts by weight of the solids content of the rubber latex (C) is 30:70 to 80:

20.

3. 3. The synthetic fiber cord for rubber material reinforcement according to claim 1, wherein the adhesive treatment agent has a solid content weight ratio of the lignin (A), the blocked isocyanate compound (B), and the rubber latex (C) of ((solid content of A) + (solid content of B)):(solid content of C) = 10:90 to 60:

40.

4. The synthetic fiber cord for reinforcing rubber materials according to any one of claims 1 to 3, characterized in that the Gurley cord hardness per unit of resin adhered to the cord is 1 to 10 mN / % or less, and the rate of change in Gurley cord hardness after heating is 100% to 240%.

5. The synthetic fiber cord for reinforcing rubber materials according to any one of claims 1 to 4, characterized in that the synthetic fiber is treated with a pre-coating agent before being treated with the adhesive treatment agent, and the pre-coating agent is an epoxy compound with a concentration of 1 to 6%.

6. 5. A polyester fiber cord for reinforcing rubber materials according to any one of claims 1 to 4, characterized in that the synthetic fiber is treated with a precoating agent before being treated with the adhesive treatment agent, wherein the precoating agent contains at least an epoxy compound and a blocked isocyanate compound (solids weight ratio of 10:0 to 10:30) at a concentration of 1 to 6%.

7. A method for producing a synthetic fiber cord for reinforcing rubber materials, comprising: adhering to twisted synthetic fibers an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C), the adhesive treatment agent having a solids weight ratio of the lignin (A) to the blocked isocyanate compound (B) of (solids content of A):(solids content of B) of 10:1 to 10:30, and a ratio of CR to PB latex in 100 parts by weight of the solids content of the rubber latex (C) of 30:70 to 80:20, followed by heat treatment.

8. 8. The method for producing a synthetic fiber cord for reinforcing rubber materials according to claim 7, wherein the adhesive treatment agent has a solid content weight ratio of the lignin (A), the blocked isocyanate compound (B), and the rubber latex (C) of ((solid content of A) + (solid content of B)):(solid content of C) = 10:90 to 60:

40.

9. 9. The method for producing a synthetic fiber cord for reinforcing rubber materials according to claim 7, further comprising the steps of applying a pre-coating agent to the synthetic fiber and then heat-treating it, before applying an adhesive treatment agent to the synthetic fiber and then heat-treating it, wherein the pre-coating agent is an epoxy compound with a concentration of 1 to 6%.

10. 9. The method for producing a synthetic fiber cord for reinforcing rubber materials according to claim 7 or 8, characterized in that it comprises a step of applying a precoating agent to the synthetic fiber and then heat-treating it, before applying an adhesive treatment agent to the synthetic fiber and then heat-treating it, and the precoating agent contains at least an epoxy compound and a blocked isocyanate compound (solids weight ratio of 10:0 to 10:30) at a concentration of 1 to 6%.

Images