Synthetic fiber cord for reinforcing automobile hoses and its manufacturing method

Abstract

To provide a synthetic fiber cord for automobile hose reinforcement that has excellent adhesion with an ethylene-α-olefin-nonconjugated diene copolymer rubber compound (EPDM rubber), can suppress generation of resin coagulation in a dipping step, improves process passability in production of a hose (or prevents the adhesive from coming off the synthetic fiber cord surface), and can provide a hose being flexible and excellent in liquid leak resistance of a caulking part; and further provide a synthetic fiber cord for automobile hose reinforcement comprising a novel adhesive treatment agent being free of resorcin and formalin and suitable for a reduced environmental load.SOLUTION: A synthetic fiber cord for automobile hose reinforcement comprises a synthetic fiber treated with an adhesive treatment agent comprising at least lignin (A), a blocked isocyanate compound (B), and rubber latex (C). With total solid content of the adhesive treatment agent being 100 wt.%, content of the lignin (A) is 5-50 wt.%. In the adhesive treatment agent, a solid weight ratio between the lignin (A) and the blocked isocyanate compound (B) is expressed as (solid content of A): (solid content of B)=10: 1-10: 20. In the solid content 100 pts.mass of the rubber latex (C), PB latex is 20-100 pts.mass. A dry film of the adhesive treatment agent has maximum-point strength of 0.2 MPa-1.6 MPa and maximum-point elongation of 2%-120%. The synthetic fiber cord has a single twisting structure with a twisting coefficient of 80-800.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a synthetic fiber cord for reinforcing an automobile hose. [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 reinforcing fiber cords for automobile hoses. However, due to the inertness of the surface of the synthetic fibers themselves, they have the problem of poor adhesion to rubber. In recent years, EPDM rubber, which has excellent high-temperature properties, has been mainly 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 have adhesive properties with 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 applied adhesive composition 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, when the fiber cord is used to reinforce brake hoses, radiator hoses, car air conditioning hoses, and the like, both ends are crimped with metal fittings for use as a product. However, when the hose is in use, the hose is subject to thermal aging and is repeatedly exposed to heat cycles from high to low temperatures, which can lead to problems such as liquid leakage from the parts of the hose where the metal fittings are crimped.

[0007] In an attempt to solve the above problem, for example, the following Patent Documents 1 to 8 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 a hose, 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.

[0013] Patent Document 6 discloses a polyamide fiber cord for rubber reinforcement that is treated with an RFL first treatment liquid that is substantially free of chlorine compounds, and then treated with a second treatment liquid that contains a chlorophenol-based compound.

[0014] Patent Document 7 discloses a dipped cord made of polyvinyl alcohol filaments and an RFL resin, in which the RFL resin is unevenly distributed in the vicinity of the surface layer of the cord.

[0015] Patent Document 8 discloses an aqueous adhesive composition containing a specific tri- or higher functional blocked isocyanate oligomer, a latex, a polyacrylate or lignin compound, and an additive. [Prior art documents] [Patent documents]

[0016] [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 [Patent Document 6] Japanese Patent Application Publication No. 11-229275 [Patent Document 7] Japanese Patent Application Laid-Open No. 2015-196912 [Patent Document 8] U.S. Patent Application Publication No. 2020 / 0024416 Summary of the Invention [Problem to be solved by the invention]

[0017] 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 although it does exhibit some adhesion to EPDM rubber, it is insufficient for practical use and has insufficient processability and leakage resistance. Patent Document 5 has improved processability and leakage resistance, but uses a conventional RFL adhesive, which has the problem of a large environmental impact. Patent Document 6 has improved heat resistance and cord flexibility, but uses a conventional RFL adhesive, which has the problem of a large environmental impact. Patent Document 7 has improved adhesion to rubber and leakage resistance, but uses a conventional RFL adhesive, which has the problem of a large environmental impact. The adhesive of Patent Document 8 does not contain resorcinol or formalin, and is advantageous in reducing the environmental impact compared to conventional RFL adhesives, but it has poor adhesion to EPDM rubber, and is insufficient in processability and leakage resistance. Furthermore, in all of Patent Documents 1 to 8, the problem of resin coagulation occurring during the dipping process remains.

[0018] The present invention has been made as a result of studies aimed at solving the problems in the prior art described above.

[0019] Specifically, the object of the present invention is to provide a synthetic fiber cord for reinforcing automobile hoses that has good adhesion to ethylene-α-olefin-non-conjugated diene copolymer rubber compounds (hereinafter referred to as "EPDM rubber"), can suppress the generation of resin coagulation during the dipping process, and can provide hoses that are easy to pass through during hose manufacturing, i.e., that are prevented from the adhesive falling off from the synthetic fiber cord surface, and that have excellent flexibility and resistance to liquid leakage at the crimped portion. Another object of the present invention is to provide a synthetic fiber cord for reinforcing automobile hoses that does not contain resorcinol or formalin and is made from a new adhesive treatment agent that is advantageous in reducing the environmental load, and a method for producing the same. [Means for solving the problem]

[0020] In order to solve the above problems, the present invention employs the following means.

[0021] That is, (1) a synthetic fiber cord for reinforcing an automobile hose, the synthetic fiber cord being made of synthetic fibers treated with an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C), wherein the content of lignin (A) is 5 to 50% by weight when the total solid content of the adhesive treatment agent is taken as 100% by weight, the solid content 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 10:20, the PB latex is 20 to 100 parts by weight per 100 parts by weight of the solid content of the rubber latex (C), and the dried film of the adhesive treatment agent has a maximum point strength of 0.2 MPa to 1.6 MPa, a maximum point elongation of 2% to 120%, and a single twist structure with a twist coefficient of 80 to 800.

[0022] (2) The synthetic fiber according to (1) above is at least one fiber selected from the group consisting of polyester fiber, polyamide fiber, and polyvinyl alcohol fiber. Automotive Hose Synthetic fiber cord for reinforcement.

[0023] (3) A synthetic fiber cord for reinforcing an automobile hose according to (1) or (2) above, characterized in that the lignin (A) has a number-average molecular weight of 10,000 to 60,000 and a weight-average molecular weight of 80,000 to 130,000.

[0024] (4) A synthetic fiber cord for reinforcing an automobile hose, 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. and a blocked isocyanate compound in a solids weight ratio of 10:0 to 10:30. , The amount of pre-coating agent attached to the synthetic fiber is 0.1 to 3 parts by weight of solid content of the pre-coating agent per 100 parts by weight of synthetic fiber. The synthetic fiber cord for reinforcing an automobile hose according to any one of the above (1) to (3), characterized in that:

[0025] (5) The synthetic fiber cord for reinforcing an automobile hose according to any one of (1) to (4) above, wherein the blocked isocyanate compound (B) is an HDI-based blocked isocyanate or an MDI-based oxime-blocked isocyanate.

[0026] (6) The synthetic fiber cord for reinforcing an automobile hose according to any one of (1) to (5) above, characterized in that the adhesive treatment agent has a coagulation rate of 4.0% or less in a Maron mechanical stability test.

[0027] (7) The synthetic fiber cord for reinforcing an automobile hose according to any one of (1) to (6) above, wherein in the adhesive treatment agent, the solid content weight ratio of the lignin (A), the blocked isocyanate compound (B), and the rubber latex (C) is ((solid content of A) + (solid content of B)):(solid content of C) = 10:90 to 60:40.

[0028] (8) A synthetic fiber cord for reinforcing an automobile hose according to any one of the above (1) to (7), characterized in that the synthetic fiber is a polyester fiber, 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%.

[0029] (9) A synthetic fiber cord for reinforcing an automobile hose according to any one of the above (1) to (7), characterized in that the synthetic fiber is a polyamide fiber, 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%.

[0030] (10) An automobile hose comprising the synthetic fiber cord for reinforcing an automobile hose according to any one of (1) to (9) above.

[0031] (11) A method for producing a single-twisted synthetic fiber having a twist coefficient of 80 to 800, which contains at least lignin (A), a blocked isocyanate compound (B), and rubber latex (C), and which comprises adhering an adhesive treatment agent having the following properties to the synthetic fiber and heat-treating the synthetic fiber: Automotive HoseA method for manufacturing synthetic fiber reinforcing cords. (a) The content of lignin (A) is 5 to 50% by weight when the total solid content in the adhesive treatment agent is 100 parts by weight. (b) The solid weight ratio of the lignin (A) to the blocked isocyanate compound (B) is (solid content of A):(solid content of B)=10:1 to 10:20 (c) 20 to 100 parts by weight of PB latex in 100 parts by weight of the solid content of the rubber latex (C) (d) When the adhesive treatment agent is made into a dry film, the dry film has a maximum strength of 0.2 MPa to 1.6 MPa and a maximum elongation of 2% to 120% (12) The lignin (A) according to (11), wherein the number-average molecular weight of the lignin (A) is 10,000 to 60,000 and the weight-average molecular weight is 80,000 to 130,000. Automotive Hose A method for manufacturing synthetic fiber reinforcing cords.

[0032] (13) A process for applying a pre-coating agent to synthetic fibers and heat-treating the fibers before applying the adhesive treatment agent to the fibers and heat-treating the fibers, wherein the pre-coating agent is an epoxy compound and a blocked isocyanate compound in a solids weight ratio of 10:0 to 10:30. , The amount of pre-coating agent attached to the synthetic fiber is 0.1 to 3 parts by weight of solid content of the pre-coating agent per 100 parts by weight of synthetic fiber. The method for producing a synthetic fiber cord for reinforcing an automobile hose according to (11) or (12) above, characterized in that:

[0033] (14) The method for producing a synthetic fiber cord for reinforcing an automobile hose according to any one of (11) to (13) above, wherein the synthetic fiber is a polyester fiber, and the hot stretch tension in the step of heat treatment after the adhesive treatment agent is applied is 0.3 to 2.5 cN / dtex, and the normalizing tension is 0.1 to 1.5 cN / dtex.

[0034] (15) The method for producing a synthetic fiber cord for reinforcing an automobile hose according to any one of (11) to (13) above, wherein the synthetic fiber is a polyamide fiber, and the hot stretch tension in the step of heat treatment after the adhesive treatment agent is applied is 0.05 to 1 cN / dtex, and the normalizing tension is 0.05 to 1 cN / dtex. [Effects of the Invention]

[0035] According to the present invention, it is possible to provide a synthetic fiber cord for reinforcing automobile hoses, which has good adhesion to ethylene-α-olefin-non-conjugated diene copolymer rubber compounds (EPDM rubbers), can suppress the generation of resin coagulation during the dipping process, can suppress process passability during hose manufacturing (detachment of adhesive from the synthetic fiber cord surface), and can provide hoses that are flexible and have excellent liquid leakage resistance at the crimped portion.Furthermore, it is possible to provide a synthetic fiber cord for reinforcing automobile hoses, which is made from a new adhesive treatment agent that does not contain resorcinol or formalin and is advantageous in reducing the environmental load. [Brief explanation of the drawings]

[0036] [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

[0037] The present invention will be described in detail below.

[0038] The synthetic fiber cord for reinforcing an automobile hose 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).

[0039] [Synthetic fiber cord for reinforcing automobile hoses] 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 for automotive hose applications, it is particularly preferable to use at least one selected from polyester fibers, nylon fibers, and polyvinyl alcohol-based fibers.

[0040] (polyester fiber) 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] (Polyamide fiber) 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.

[0046] 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.

[0047] 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.

[0048] (Polyvinyl alcohol fiber) 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.

[0049] (Fiber morphology) 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.

[0050] The synthetic fiber cord for reinforcing an automobile hose 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 number of twists in the cord must be such that the twist coefficient, defined by the following formula, is in the range of 80 to 800, preferably 130 to 750. Twist coefficient = {number of twists (t / 10cm) × (total fineness denier)} 1 / 2} A twist coefficient of less than 80 can lead to a decrease in adhesive strength and deterioration of leakage resistance. A twist coefficient 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). This is also undesirable because it makes the hose more susceptible to expansion due to structural elongation of the cord and increases the thickness of the reinforcing cord layer. Furthermore, a double-twisted cord, such as that used in tire cords, in which multiple single-twisted cords are further aligned and twisted, is undesirable because it reduces strength and worsens leakage resistance.

[0051] (Treatment agent) The synthetic fiber cord for automobile hose 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 solvents such as water, are distilled off, and the blocking agent of the blocked isocyanate is removed, causing a reaction by the isocyanate group. In other words, in synthetic fibers treated with the adhesive treatment agent, 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 cord for automobile hose reinforcement of the present invention is a synthetic fiber cord in which an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C) is applied to polyester fiber in the same bath (one bath), rather than a so-called two-bath treatment method, which is a known adhesive treatment method for polyester fiber, in which (A), (B), and (C) are separately mixed in the first-bath adhesive and the second-bath adhesive, respectively. Furthermore, the synthetic fiber cord of the present invention does not contain resorcinol-formaldehyde resin in either the first-bath adhesive or the second-bath adhesive.

[0052] 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.

[0053] As a result of extensive investigation into the preferred form of the lignin (A) used in the present invention, it was found that the number-average molecular weight is preferably 10,000 to 60,000 and the weight-average molecular weight is preferably 80,000 to 130,000, and more preferably 20,000 to 50,000 and 90,000 to 120,000. If the number-average molecular weight and weight-average molecular weight of the lignin exceed the upper limits of these ranges, fatigue resistance may be insufficient, the storage stability of the adhesive treatment agent may deteriorate, and continuous production may become difficult due to the frequent occurrence of coagulation during the dipping process. If the number-average molecular weight and weight-average molecular weight are below the lower limits of these ranges, the initial adhesive strength to the rubber and fatigue resistance may decrease, which is undesirable. Furthermore, the weight-average molecular weight (Mw) / number-average molecular weight (Mn) ratio is preferably 2.5 to 5.0, more preferably 2.8 to 4.7. Outside these ranges, adhesive strength and fatigue resistance may be insufficient. The number average molecular weight and weight average molecular weight in the present invention are values ​​measured by the methods described in the Examples section.

[0054] 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. Examples of blocked isocyanate compounds include reaction products of polyisocyanate compounds having a skeleton such as tolylene diisocyanate (TDI), metaphenylene diisocyanate (MDI), diphenylmethane diisocyanate (HDI), hexamethylene diisocyanate, or triphenylmethane triisocyanate with blocking agents such as phenols (e.g., phenol, cresol, or resorcinol), lactams (e.g., ε-caprolactam or valerolactam), or oximes (e.g., acetoxime, methyl ethyl ketoxime, or cyclohexane oxime).

[0055] Among these blocked isocyanate compounds, it is most preferable to select from HDI-based blocked isocyanates, which are the reaction product of hexamethylene diisocyanate and a blocking agent, or MDI-based oxime-blocked isocyanates, which are the reaction product of diphenylmethane diisocyanate and an oxime-based blocking agent, in order to obtain good adhesive strength and fatigue resistance. Diphenylmethane diisocyanate (MDI) can be selected from 2,2'-MDI, 2,4'-MDI, and 4,4'-MDI, but monomeric MDI (4,4'-MDI) is most preferable from the standpoint of adhesive strength and fatigue resistance. Polymeric MDI with trifunctional isocyanate groups is not preferred, as it may result in reduced adhesive strength and fatigue resistance. Furthermore, the dissociation temperature of the blocking agent for HDI-based blocked isocyanates or MDI-based oxime-blocked isocyanates is preferably 100 to 160°C. A dissociation temperature within this range is preferable because it has good reactivity during heat treatment and can exhibit higher adhesive strength.

[0056] 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.

[0057] Among these, from the viewpoint of improving adhesion to EPDM rubber, it is necessary to contain butadiene rubber latex (PB latex), and the PB latex must be contained in an amount of 20 to 100 parts by weight, preferably 30 to 100 parts by weight, per 100 parts by weight of the solid content of the rubber latex (C).More preferably, in addition to the PB latex, at least one selected from vinylpyridine-styrene-butadiene rubber latex (VP latex) and chloroprene rubber latex (CR latex) is mixed.

[0058] 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.

[0059] In the adhesive treatment agent of the present invention, when the total solid content in the adhesive treatment agent is taken as 100% by weight, the content of the lignin derivative (A) must be 5 to 50% by weight, preferably 7 to 45% by weight, and more preferably 10 to 40% by weight. If it is less than 5% by weight or exceeds 50% by weight, the adhesive strength and fatigue resistance may be insufficient.

[0060] The weight ratio of the lignin (A) to the blocked isocyanate compound (B) (solid content of A):(solid content of B) must be 10:1 to 10:20, 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. On the other hand, if the amount of the blocked isocyanate compound is too large and exceeds this weight ratio, the cord may become stiff, and the fatigue resistance of the hose may deteriorate.

[0061] 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.

[0062] The adhesive treatment agent used in the present invention, when used to form a dried film, must have a maximum strength of 0.2 MPa to 1.6 MPa, preferably 0.3 MPa to 1.4 MPa, and more preferably 0.5 MPa to 1.4 MPa. A maximum strength of less than 0.2 MPa may result in insufficient adhesive strength, while a maximum strength of more than 1.6 MPa may result in poor fatigue resistance as a hose. The maximum elongation of the dried film must be 2% to 120%, preferably 4% to 100%, and more preferably 20% to 100%. A maximum elongation of less than 2% may result in poor fatigue resistance, while a maximum elongation of more than 120% may result in poor adhesive strength. The methods for preparing the dried film and measuring the maximum strength and maximum elongation are as described in the Examples section. However, if it is difficult to use these methods, equivalent methods can be used.

[0063] 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 maximum strength and maximum elongation of the dried film of the adhesive treatment agent must be within the specified ranges. By containing them in the same treatment agent and ensuring that they fall within the specified ranges of the present invention, the adhesive treatment agent will exhibit excellent adhesion between the rubber and fiber and fatigue resistance as a hose.

[0064] The maximum point strength and maximum point 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 point strength can be adjusted to a higher value by increasing the amount of blocked isocyanate compound (B) mixed into the adhesive treatment agent. Furthermore, the maximum point elongation can be adjusted to a higher value by, for example, mixing rubber latex into the adhesive treatment agent and increasing the amount of rubber latex mixed into the adhesive treatment agent. On the other hand, adding highly reactive and crosslinkable compounds such as epoxy compounds or oxazoline group-containing substances in addition to (A), (B), and (C) is not recommended because the strength will be higher than the specified range and the elongation will be lower than the specified range, which may lead to a deterioration in fatigue resistance in the rubber.

[0065] Furthermore, in the present invention, it is preferable that the adhesive treatment agent containing at least the three substances (A), (B), and (C) exhibit a coagulation ratio of 4.0% or less in the Maron mechanical stability test. While the specific method of the Maron mechanical stability test will be described later, this test indicates the stability of the adhesive treatment agent when mechanical shear stress is applied to the agent, and is utilized in the present invention as a measure of the degree of coagulation generation during the dipping process in which the adhesive treatment agent is applied to fibers. The coagulation ratio in the Maron mechanical stability test is more preferably 3.5% or less, and even more preferably 3.0% or less. If it exceeds 4.0%, coagulation occurs frequently during the dipping process, making continuous production difficult, and the coagulation generated may adhere to the fiber cord, leading to deterioration of adhesion to the rubber. A coagulation ratio in this test below the specified value of the present invention is preferable because it improves processability during the dipping process.

[0066] There are no particular limitations on the method for keeping the proportion of coagulum in the Maron mechanical stability test below the specified level of the present invention, but it can be adjusted by optimizing the selection of the types and blending ratios of the lignin (A), blocked isocyanate (B), and rubber latex (C) used. Alternatively, a method of adding an additional surfactant is also preferred. Anionic surfactants are preferred as surfactants, and examples thereof include sulfate ester salts, polyoxyethylene alkyl ether sulfate ester salts, and alkylbenzene sulfonates.

[0067] The adhesive treatment agent used in the present invention is a solids solution or dispersion in water, with a total solids concentration of preferably 5 to 25% by weight, more preferably 10 to 20% by weight, and even more preferably 12 to 18% by weight. Outside this range, the adhesive strength may decrease. Outside this range, a sufficient amount of solids may not be applied to the fibers, or cohesive failure may occur in the adhesive solids, which may result in a decrease in the adhesive strength.

[0068] The amount of the adhesive treatment agent attached to the synthetic fiber is preferably 1 to 15 parts by weight, more preferably 1.5 to 10 parts by weight, in terms of solid content, per 100 parts by weight of the synthetic fiber. If the amount is outside this range, the adhesive strength may decrease.

[0069] 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).

[0070] The pre-coating agent is an epoxy compound. and a blocked isocyanate compound in a solids weight ratio of 10:0 to 10:30. The concentration is preferably 0.1 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 in terms of solid content per 100 parts by weight of synthetic fiber. Outside this range, adhesive strength may decrease.

[0071] (Synthetic fiber cord for reinforcing automobile hoses using polyester fibers) The synthetic fiber cord for reinforcing an automobile hose using polyester fiber according to 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. While 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, and 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.

[0072] (Synthetic fiber cord using polyamide fiber for reinforcing automobile hoses) The synthetic fiber cord for reinforcing automobile hoses using polyamide fiber according to 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. While there are no particular limitations on the method for adjusting the Gurley cord hardness, for example, reducing the amount of resin attached can decrease the Gurley cord hardness, while increasing the amount of resin attached can increase the Gurley cord hardness. Furthermore, during the heat treatment in the dipping step described below, the Gurley cord hardness can be decreased by decreasing the heat treatment temperature and / or heat treatment time, and increased by increasing the heat treatment temperature and / or heat treatment time. This can also be achieved by setting the tension to 0.05 to 1 cN / dtex during the mechanical softening treatment step after passing through the normalizing zone in the dipping step described below.

[0073] (Synthetic fiber cord for reinforcing automobile hoses using polyvinyl alcohol-based fibers) The synthetic fiber cord for reinforcing automobile hoses using polyvinyl alcohol fiber according to 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. While there are no particular limitations on the method for adjusting the Gurley cord hardness, for example, reducing the amount of resin attached can decrease the Gurley cord hardness, while increasing the amount of resin attached can increase the Gurley cord hardness. Furthermore, during the heat treatment in the dipping step described below, the Gurley cord hardness can be decreased by decreasing the heat treatment temperature and / or heat treatment time, and increased by increasing the heat treatment temperature and / or heat treatment time. This can also be achieved by setting the tension to 0.05 to 5 cN / dtex during the mechanical softening treatment step after passing through the normalizing zone in the dipping step described below.

[0074] The synthetic fiber cord for reinforcing automobile hoses 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), can suppress the generation of resin coagulation during the dipping process, and can suppress process passability (detachment of adhesive from the synthetic fiber cord surface) during hose manufacturing. It also makes it possible to provide a hose that is flexible and has excellent liquid leakage resistance at the crimped portion.

[0075] Automobile hoses containing the synthetic fiber cord for reinforcing automobile hoses according to the present invention are environmentally friendly rubber products that do not use resorcinol or formalin, yet can exhibit performance equal to or better than that of those using conventional RFL.

[0076] [Method of manufacturing synthetic fiber cord for reinforcing automobile hoses] Next, a method for producing the synthetic fiber cord for reinforcing automobile hoses of the present invention will be described.

[0077] When the synthetic fiber is a polyester fiber, for example, polyethylene terephthalate chips having 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.

[0078] When the synthetic fiber is a polyamide fiber, for example, 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 drawn 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.

[0079] Polyvinyl alcohol fibers can also be produced by known methods.

[0080] One strand of the synthetic fiber obtained as described above is twisted to have a twist coefficient in the range of 80 to 800 as defined above to form a single twisted yarn cord.

[0081] An example of a method for producing a synthetic fiber cord for rubber reinforcement according to the present invention is a method in which an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C) and having the following properties is adhered to a synthetic fiber in the same bath, followed by a heat treatment: (a) The content of lignin (A) is 5 to 50% by weight when the total solid content in the adhesive treatment agent is 100 parts by weight. (b), wherein the solid weight ratio of the lignin (A) to the blocked isocyanate compound (B) is (solid content of A):(solid content of B)=10:1 to 10:20. (c) 20 to 100 parts by weight of PB latex in 100 parts by weight of the solid content of the rubber latex (C) (d) When the adhesive treatment agent is made into a dry film, the dry film has a maximum strength of 0.2 MPa to 1.6 MPa and a maximum elongation of 2% to 120% If the weight ratio of (solids content of A):(solids content of B) is outside this range and the amount of blocked isocyanate compound is small, the adhesive strength may be insufficient. If the amount of blocked isocyanate compound is large and exceeds this weight ratio, the cord may become hard and the fatigue resistance of the hose may deteriorate.

[0082] 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.

[0083] 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 the raw material by running the twisted yarn cord or the 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. Note that, in addition to dipping, any other method can be used to attach the adhesive treatment agent to polyester fibers, such as spraying the adhesive treatment agent from a nozzle.

[0084] In order to control the amount of solids of the adhesive treatment agent attached to the polyester fiber, means such as squeezing with a pressure roller, scraping with a scraper, blowing with air, and suction may be used.

[0085] 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.

[0086] The adhesive treatment agent used in the method for producing a synthetic fiber cord for reinforcing an automobile hose of the present invention must have a maximum strength of 0.2 MPa to 1.6 MPa in a dried film, and a maximum elongation of 2% to 120% in a dried film.

[0087] Furthermore, in the adhesive treatment agent used in the method for producing a synthetic fiber cord for reinforcing an automobile hose of the present invention, the lignin (A) 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. If the number average molecular weight and weight average molecular weight of the lignin are outside these ranges, the adhesive strength and fatigue resistance of the hose may be insufficient, and therefore it is preferable to select a lignin within these ranges.

[0088] 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.

[0089] In the method for producing a polyester fiber cord for reinforcing an automobile hose of the present invention, a precoat agent may be applied to the synthetic fiber and heat-treated before the adhesive treatment agent (adhesive treatment agent containing at least lignin, a blocked isocyanate compound, and rubber latex) is applied to the synthetic fiber and heat-treated.

[0090] The pre-coating agent is an epoxy compound. and a blocked isocyanate compound in a solids weight ratio of 10:0 to 10:30. The concentration is preferably 0.1 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 in terms of solid content per 100 parts by weight of synthetic fiber. Outside this range, adhesive strength may decrease.

[0091] When applying the pre-coating agent, the same dipping method as described above can be used. That is, a preferred method is to dip the twisted synthetic fiber cord into the pre-coating agent in a dip bath, then dry the cord at a temperature of preferably 100 to 150°C, and then heat-treat the cord at 200 to 255°C. The same methods as described above can be used to control the amount of solids applied and to soften the cord.

[0092] 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. For polyester fibers, the tension during hot treatment (hot stretch tension) is preferably 0.3 to 2.5 cN / dtex, and the tension during 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. In the case of polyamide fibers, the tension during hot treatment (hot stretch tension) is preferably 0.05 to 1 cN / dtex and the tension during normalizing treatment (normalizing tension) is preferably 0.05 to 1 cN / dtex, and the tension during hot treatment (hot stretch tension) is more preferably 0.3 to 0.8 cN / dtex and the tension during normalizing treatment (normalizing tension) is more preferably 0.3 to 0.8 cN / dtex. If the hot stretch tension is outside this range, the adhesive may be unevenly distributed on the surface layer of the cord, which may worsen processability or reduce adhesive strength. If the normalizing tension is outside this range, the cord may experience increased thermal shrinkage, which may reduce compliance with the rubber and reduce adhesive strength. In the case of polyvinyl alcohol-based fibers, the tension during hot treatment (hot stretch tension) is preferably 0.05 to 2.5 cN / dtex and the tension during normalizing treatment (normalizing tension) is preferably 0.05 to 1.5 cN / dtex, and more preferably the tension during hot treatment (hot stretch tension) is 0.3 to 1.5 cN / dtex and the tension during normalizing treatment (normalizing tension) is 0.1 to 1.0 cN / dtex.If the hot stretch tension is outside this range, the adhesive may be unevenly distributed on the surface layer of the cord, which may worsen the processability or reduce the adhesive strength. If the normalizing tension is outside this range, the cord may experience increased thermal shrinkage, which may reduce its ability to conform to the rubber, resulting in a reduction in the adhesive strength.

[0093] The synthetic fiber cord for reinforcing automobile hoses of the present invention obtained in this manner 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), can suppress the generation of resin coagulation during the dipping process, and can suppress process passability (detachment of adhesive from the synthetic fiber cord surface) during hose manufacturing. It can also provide a hose that is flexible and has excellent liquid leakage resistance at the crimped portion. [Example]

[0094] 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.

[0095] (1) Amount of adhesive applied The adhesive adhesion was determined according to the dip pick-up mass method of JIS L1017 (2002).

[0096] (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. 2The pressing pressure was adjusted so that the force was such that the pressure was within the range of 1 / 300 psi. 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 / inch. 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).

[0097] (3) Maximum strength and elongation of the dried adhesive film The adhesive treatment agent was applied to a glass plate so that the dried film would be 0.5 mm thick, and after drying at room temperature for 72 hours, it was peeled off from the glass plate and heat-treated in an oven at 120°C for 15 minutes, and then in an oven at 240°C for 2 minutes. This was punched out using a No. 2 dumbbell mold and subjected to a tensile test using an Orientec Tensilon RTM-100 testing machine at a crosshead speed of 50 mm / min in an atmosphere of 25°C to measure strength and elongation. The strength and elongation at the point where the strength was maximum were determined for each sample, and the arithmetic mean value of the strength for 6 samples was taken as the maximum point strength, and the arithmetic mean value of the elongation for 6 samples was taken as the maximum point elongation.

[0098] (4) Maron type mechanical stability test The proportion of coagulated material in the Maron mechanical stability test for adhesive treatment agents was measured using the following method. Using a Maron mechanical stability tester manufactured by Yasuda Seiki Seisakusho, 50 g of adhesive treatment agent was subjected to mechanical shear at a rotor rotation speed of 1,000 rpm, a rotor load of 10 kg, and a rotation time of 3 minutes, and then the sample was filtered through a 100-mesh wire screen. The captured coagulated material was dried and then measured for mass, and the ratio of the amount of coagulated material to the solid mass of the original adhesive treatment agent was calculated in weight percent, and this value was taken as the proportion of coagulated material (%).

[0099] (5) 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.

[0100] 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.

[0101] 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 / %). 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).

[0102] (6) 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 (5) above. The value in (6) was divided by the value in (5) to obtain the rate of change (%) in the Gurley cord hardness after heating.

[0103] (7) Formation of aggregates during the dipping process In the dipping and heat treatment process using a Ritzler Computreator treatment machine, a twisted yarn cord was immersed in the adhesive treatment agent of the present invention and run for 1 hour at a cord running speed of 20 m / min. After that, the amount of coagulated material deposited on the turn roll with which the cord came into contact as it ran through an oven at 120°C was checked and rated (coagulated material: much = B>A>S=none). In the present invention, S and A were set as pass marks for process passability that could withstand practical use, with S being superior in practical use.

[0104] (8) 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, and then taken up through yarn feed nip rolls 10. 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.

[0105] (9) 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. 2The 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.

[0106] (10) Measurement of number average molecular weight and weight average molecular weight of lignin The number-average molecular weight and weight-average molecular weight of lignin were measured by GPC (gel permeation chromatography). A solvent (ammonia buffer / methanol) was added to the lignin sample, and the mixture was stirred at room temperature to dissolve, followed by filtration through a 0.5 μm filter. Then, measurement was performed using GPC, peaks were detected using a UV detector, and the molecular weight was measured as a relative value based on polyethylene oxide and polyethylene glycol. The measurement results are described in the Examples below. Detailed measurement conditions are described below. Measuring equipment: Shimadzu Corporation Columns used: 1 TSKgel GMPWXL, 1 G3000PWXL (φ7.8 mm x 30 cm, Tosoh) Solvent: 0.1 M ammonia buffer (pH 11) / methanol (4 / 1, v / v) Standard materials: Monodisperse polyethylene oxide and polyethylene glycol manufactured by Tosoh and Agilent Detector: UV detector (Shimadzu SPD-M20A).

[0107] (Examples 1 to 3, 5 to 7, 9 to 10, Comparative Examples 1 to 7) Glycerol polyglycidyl ether ("Denacol" EX313, manufactured by Nagase Chemical Industries, Ltd.), blocked isocyanate compound (DM-6400, manufactured by Meisei Chemical Industry Co., Ltd.), VP latex (Pyratex, manufactured by Nippon A&L Co., Ltd.), and PB latex ("Nipol" LX-111A, manufactured by Nippon Zeon Co., Ltd.) were mixed in a solids ratio of 15:30:25:30, and then diluted with water to obtain precoat agent (A) with a total solids content of 4.0 wt%.

[0108] Furthermore, lignin (A), blocked isocyanate compound (B), rubber latex (C)(i), and rubber latex (C)(ii) were mixed with water so that the solid contents thereof were in the ratios shown in Table 1, to obtain adhesive treatment agents with a total solids concentration of 15% by weight. The maximum point strength and maximum point elongation of the dried film of the obtained adhesive treatment agent were measured. Furthermore, the percentage of coagulated material (%) was measured using the method described in the Maron mechanical stability test described above.

[0109] A single 1670 dtex polyester multifilament yarn (manufactured by Toray Industries, Inc., "Tetoron" 1670T-288-702C) was twisted to the twist coefficient shown in Table 1 to obtain a twisted yarn cord having a single twist structure.

[0110] 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 then heat-treated at 245°C for 1 minute. The cord was then immersed in an adhesive treatment agent containing the components (A), (B), and (C), then dried at 120°C for 2 minutes, and then 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. Here, in the treatment with the adhesive treatment agent containing (A), (B), and (C), the cord was run at a running speed of 20 m / min for 1 hour, and after the treatment was completed, the amount of coagulated material deposited on the turn roll with which the cord came into contact as it ran through the 120°C oven of the Computreator treatment machine was confirmed and judged as (coagulated material: much = B>A>S=none).

[0111] The adhesive solid content of the obtained synthetic fiber cord for reinforcing automobile hoses was 1.1 parts by weight of the precoating agent per 100 parts by weight of the synthetic fiber, and 4.0 parts by weight of the adhesive treatment agent containing (A), (B), and (C) per 100 parts by weight of the synthetic fiber.

[0112] The components of the adhesive treatment agent shown in Table 1 are as follows: (A)-1: Lignin (manufactured by Nippon Paper Industries Co., Ltd., sodium lignosulfonate, "Vanilex" N, number average molecular weight 29,000, weight average molecular weight 105,000) (A)-2: Lignin (manufactured by Nippon Paper Industries Co., Ltd., sodium lignosulfonate, "Vanilex" RN, number-average molecular weight 34,000, weight-average molecular weight 112,000) (A)-3: Lignin (manufactured by Nippon Paper Industries Co., Ltd., sodium lignosulfonate, "Pearlex" NP, number average molecular weight 97,000, weight average molecular weight 146,000) (B)-1: Blocked isocyanate (Meisei Chemical Industry Co., Ltd., DM-6400, oxime-blocked diphenylmethane diisocyanate, dissociation temperature 120 to 160°C) (B)-2: Blocked isocyanate (Meisei Chemical Industry Co., Ltd., SU-268A, a blocking agent adduct of hexamethylene diisocyanate, dissociation temperature 100 to 130°C) (B)-3: Blocked isocyanate (Meisei Chemical Industry Co., Ltd., DM-3031CONC, lactam-blocked diphenylmethane diisocyanate, dissociation temperature 160-180°C) (B)-4: Blocked isocyanate (Meisei Chemical Industry Co., Ltd., DM-7000, lactam block polymeric MDI, dissociation temperature 160 to 180°C) (C)-1: VP latex (Pilatex, manufactured by Nippon A&L Co., Ltd.). (C)-2: PB latex (manufactured by Nippon Zeon Co., Ltd., "Nipol" LX111A).

[0113] Example 4 The precoating agent was changed to precoating agent (A) with a total solids content of 7.0 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.) at a solids ratio of 10:35 and diluting with water. Treatment and evaluation were carried out in the same manner as in Example 1. The adhesive solids adhesion amount of the obtained automobile hose reinforcing cord was 1.7 parts by weight per 100 parts by weight of the precoating agent and 3.5 parts by weight per 100 parts by weight of the adhesive treatment agent containing (A), (B), and (C).

[0114] Example 8 A single 1670 dtex polyester multifilament yarn (manufactured by Toray Industries, Inc., "Tetoron" 1670T-288-707C) to which a polyepoxide compound (sorbitol polyglycidyl ether) had been previously applied by mixing the polyepoxide compound as a spinning oil in the spinning process was twisted to the twist coefficient shown in Table 1 to obtain a twisted yarn cord with a single twist structure. This twisted yarn cord was treated and evaluated in the same manner as in Example 1, except that no pre-coating agent was used and an adhesive treatment agent containing (A), (B), and (C) was applied.

[0115] (Conventional Example 1) Treatment and evaluation were carried out in the same manner as in Example 1, except that the adhesive treatment agent containing (A), (B), and (C) in Example 1 was changed to 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. This precondensation product (RF) was then 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.) at a solids weight ratio of 1:1) at a RF / L ratio of 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 adhesive solids deposition amount of the resulting automotive hose reinforcement cord was 1.1 parts by weight of precoat agent per 100 parts by weight of synthetic fiber, and 4.0 parts by weight of RFL adhesive per 100 parts by weight of synthetic fiber.

[0116] (Examples 11 to 13, 15 to 17, 19 to 20, Comparative Examples 8 to 14) Glycerol polyglycidyl ether ("Denacol" EX313, manufactured by Nagase Chemical Industries, Ltd.), blocked isocyanate compound (DM-6400, manufactured by Meisei Chemical Industry Co., Ltd.), VP latex (Pyratex, manufactured by Nippon A&L Co., Ltd.), and PB latex ("Nipol" LX-111A, manufactured by Nippon Zeon Co., Ltd.) were mixed in a solids ratio of 15:30:25:30, and then diluted with water to obtain precoat agent (A) with a total solids content of 4.0 wt%.

[0117] Furthermore, lignin (A), blocked isocyanate compound (B), rubber latex (C)(i), and rubber latex (C)(ii) were mixed with water so that the solid contents thereof were in the ratios shown in Table 2, to obtain adhesive treatment agents with a total solids concentration of 15% by weight. The maximum point strength and maximum point elongation of the dried film of the obtained adhesive treatment agent were measured. Furthermore, the percentage of coagulated material (%) was measured using the method described in the Maron mechanical stability test described above.

[0118] A single 1400 dtex polyamide multifilament yarn (Toray Industries, Inc., "Nylon" 1400T-204-1782) was twisted to the twist coefficient shown in Table 2 to obtain a twisted yarn cord having a single twist structure.

[0119] 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. The cord was then immersed in an adhesive treatment agent containing the components (A), (B), and (C), 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 2.

[0120] Here, in the treatment with the adhesive treatment agent containing (A), (B), and (C), the cord was run at a running speed of 20 m / min for 1 hour, and after the treatment was completed, the amount of coagulated material deposited on the turn roll with which the cord came into contact as it ran through the 120°C oven of the Computreator treatment machine was confirmed and judged as (coagulated material: much = B>A>S = none).

[0121] The adhesive solid content of the obtained synthetic fiber cord for reinforcing automobile hoses was 1.1 parts by weight of the precoating agent per 100 parts by weight of the synthetic fiber, and 4.0 parts by weight of the adhesive treatment agent containing (A), (B), and (C) per 100 parts by weight of the synthetic fiber.

[0122] The components of the adhesive treatment agent shown in Table 2 are as described above.

[0123] Example 14 The precoating agent was changed to precoating agent (A) with a total solids content of 7.0 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.) at a solids ratio of 10:35 and diluting with water. Treatment and evaluation were carried out in the same manner as in Example 11. The adhesive solids adhesion weight of the obtained automobile hose reinforcing cord was 1.7 parts by weight per 100 parts by weight of the precoating agent and 3.5 parts by weight per 100 parts by weight of the adhesive treatment agent containing (A), (B), and (C).

[0124] Example 18 Treatment and evaluation were carried out in the same manner as in Example 11, except that no precoating agent was used and an adhesive treatment agent containing (A), (B), and (C) was used.

[0125] (Conventional example 2) Treatment and evaluation were carried out in the same manner as in Example 11, except that the adhesive treatment agent containing (A), (B), and (C) in Example 11 was changed to 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. This precondensation product (RF) was then 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.) at a solids weight ratio of 1:1) at a RF / L ratio of 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 adhesive solids deposition amount of the resulting automotive hose reinforcement cord was 1.1 parts by weight of precoat agent per 100 parts by weight of synthetic fiber, and 4.0 parts by weight of RFL adhesive per 100 parts by weight of synthetic fiber.

[0126] (Examples 21 to 23, 25 to 27, Comparative Examples 15 to 21) Glycerol polyglycidyl ether ("Denacol" EX313, manufactured by Nagase Chemical Industries, Ltd.), blocked isocyanate compound (DM-6400, manufactured by Meisei Chemical Industry Co., Ltd.), VP latex (Pyratex, manufactured by Nippon A&L Co., Ltd.), and PB latex ("Nipol" LX-111A, manufactured by Nippon Zeon Co., Ltd.) were mixed in a solids ratio of 15:30:25:30, and then diluted with water to obtain precoat agent (A) with a total solids content of 4.0 wt%.

[0127] Furthermore, lignin (A), blocked isocyanate compound (B), rubber latex (C)(i), and rubber latex (C)(ii) were mixed with water so that the solid contents thereof were in the ratios shown in Table 3, to obtain adhesive treatment agents with a total solids concentration of 15% by weight. The maximum point strength and maximum point elongation of the dried film of the obtained adhesive treatment agent were measured. Furthermore, the percentage of coagulated material (%) was measured using the method described in the Maron mechanical stability test described above.

[0128] A single 1330 dtex polyvinyl alcohol multifilament yarn (manufactured by Kuraray Co., Ltd., Vinylon filament 1330T-200f (product number 1239)) was twisted to the twist coefficient shown in Table 3 to obtain a twisted yarn cord having a single twist structure.

[0129] The twisted yarn cord was immersed in the precoat agent (A) using a Computreator processor (manufactured by Ritzler Co., Ltd.), dried at 120°C for 2 minutes, and then heat-treated at 245°C for 1 minute. Next, the twisted yarn cord was immersed in an adhesive treatment agent containing the components (A), (B), and (C), dried at 120°C for 2 minutes, then heat-treated at 240°C for 0.5 minutes (hot treatment), and then heat-treated at 240°C for 0.5 minutes (normalization treatment). Here, in the treatment with the adhesive treatment agent containing (A), (B), and (C), the cord was run at a running speed of 20 m / min for 1 hour, and after the treatment was completed, the amount of coagulated material deposited on the turn roll with which the cord came into contact as it ran through the 120°C oven of the Computreator treatment machine was confirmed and judged as (coagulated material: much = B>A>S=none).

[0130] The adhesive solid content of the obtained synthetic fiber cord for reinforcing automobile hoses was 1.1 parts by weight of the precoating agent per 100 parts by weight of the synthetic fiber, and 4.0 parts by weight of the adhesive treatment agent containing (A), (B), and (C) per 100 parts by weight of the synthetic fiber.

[0131] The components of the adhesive treatment agent shown in Table 3 are as described above.

[0132] Example 24 The precoating agent was changed to precoating agent (A) with a total solids content of 7.0 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 10:35, and then diluting with water. Treatment and evaluation were carried out in the same manner as in Example 21. The adhesive solids adhesion amount of the obtained automobile hose reinforcing cord was 1.7 parts by weight per 100 parts by weight of the precoating agent and 3.5 parts by weight per 100 parts by weight of the adhesive treatment agent containing (A), (B), and (C).

[0133] Example 28 Treatment and evaluation were carried out in the same manner as in Example 21, except that no precoating agent was used and an adhesive treatment agent containing (A), (B), and (C) was used.

[0134] (Conventional example 3) Treatment and evaluation were carried out in the same manner as in Example 21, except that the adhesive treatment agent containing (A), (B), and (C) in Example 21 was changed to 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. This precondensation product (RF) was then 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.) at a solids weight ratio of 1:1) at a RF / L ratio of 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 adhesive solids deposition amount of the resulting automotive hose reinforcement cord was 1.1 parts by weight of precoat agent per 100 parts by weight of synthetic fiber, and 4.0 parts by weight of RFL adhesive per 100 parts by weight of synthetic fiber.

[0135] [Table 1]

[0136] [Table 2]

[0137] [Table 3]

[0138] The fiber cord for automobile hose reinforcement 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 fiber cord in unvulcanized rubber and vulcanizing it, the peel adhesion strength and air diffusion value were measured. The results are shown in Tables 1 to 3.

[0139] As can be seen from the results in Tables 1 to 3, in the case of the examples 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 has good adhesion to ethylene-α-olefin-non-conjugated diene copolymer rubber compounds (EPDM rubber), can suppress the generation of resin coagulation during the dipping process, has good processability, is flexible, and has excellent liquid leakage resistance at the crimped part. [Explanation of symbols]

[0140] 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. 1. A synthetic fiber cord for reinforcing automobile hoses, the synthetic fiber cord being made of synthetic fibers treated with an adhesive treatment agent containing at least lignin (A), a blocked isocyanate compound (B), and a rubber latex (C), wherein the content of lignin (A) is 5 to 50% by weight when the total solid content of the adhesive treatment agent is taken as 100% by weight, the solid content 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 10:20, the amount of PB latex is 20 to 100 parts by weight per 100 parts by weight of the solid content of the rubber latex (C), the dried film of the adhesive treatment agent having a maximum point strength of 0.2 MPa to 1.6 MPa and a maximum point elongation of 2% to 120%, and having a single twist structure with a twist multiplier of 80 to 800.

2. 2. The synthetic fiber cord for reinforcing an automobile hose according to claim 1, wherein the synthetic fiber is at least one fiber selected from the group consisting of polyester fiber, polyamide fiber, and polyvinyl alcohol fiber.

3. 3. The synthetic fiber cord for reinforcing an automobile hose according to claim 1, wherein the lignin (A) has a number average molecular weight of 10,000 to 60,000 and a weight average molecular weight of 80,000 to 130,000.

4. 4. A synthetic fiber cord for reinforcing automobile hoses according to any one of claims 1 to 3, 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 an epoxy compound and a blocked isocyanate compound in a solids weight ratio of 10:0 to 10:30, and the amount of precoating agent adhered to the synthetic fiber is 0.1 to 3 parts by weight in terms of solids weight per 100 parts by weight of the synthetic fiber.

5. 5. The synthetic fiber cord for reinforcing an automobile hose according to claim 1, wherein the blocked isocyanate compound (B) is an HDI-based blocked isocyanate or an MDI-based oxime-blocked isocyanate.

6. The synthetic fiber cord for reinforcing automobile hoses according to any one of claims 1 to 5, characterized in that the adhesive treatment agent has a coagulation rate of 4.0% or less in a Maron mechanical stability test.

7. 7. The synthetic fiber cord for reinforcing an automobile hose according to any one of claims 1 to 6, wherein in the adhesive treatment agent, a weight ratio of solid contents of the lignin (A), the blocked isocyanate compound (B), and the rubber latex (C) is ((solid content of A) + (solid content of B)):(solid content of C) = 10:90 to 60:

40.

8. 8. The synthetic fiber cord for reinforcing an automobile hose according to any one of claims 1 to 7, wherein the synthetic fiber is a polyester fiber, 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%.

9. 8. The synthetic fiber cord for reinforcing an automobile hose according to any one of claims 1 to 7, wherein the synthetic fiber is a polyamide fiber, 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%.

10. An automobile hose comprising the synthetic fiber cord for reinforcing an automobile hose according to any one of claims 1 to 9.

11. A method for producing a synthetic fiber cord for reinforcing an automobile hose, comprising: adhering to single-twisted synthetic fibers having a twist multiplier of 80 to 800 at least lignin (A), a blocked isocyanate compound (B), and rubber latex (C), an adhesive treatment agent having the following properties, and heat-treating the synthetic fibers: (a) The content of lignin (A) is 5 to 50% by weight when the total solid content contained in the adhesive treatment agent is 100 parts by weight. (b) The solid content weight ratio of the lignin (A) to the blocked isocyanate compound (B) is (solid content of A):(solid content of B)=10:1 to 10:20 (c) 20 to 100 parts by weight of PB latex in 100 parts by weight of the solid content of rubber latex (C) (d) When the adhesive treatment agent is made into a dry film, the dry film has a maximum strength of 0.2 MPa to 1.6 MPa and a maximum elongation of 2% to 120%.

12. 12. The method for producing a synthetic fiber cord for reinforcing an automobile hose according to claim 11, wherein the lignin (A) has a number average molecular weight of 10,000 to 60,000 and a weight average molecular weight of 80,000 to 130,000.

13. 13. The method for producing a synthetic fiber cord for reinforcing an automobile hose according to claim 11 or 12, characterized in that it comprises a step of applying a precoating agent to the synthetic fiber and then heat-treating it, before applying the adhesive treatment agent to the synthetic fiber and then heat-treating it, wherein the precoating agent contains an epoxy compound and a blocked isocyanate compound in a solids weight ratio of 10:0 to 10:30, and the amount of precoating agent applied to the synthetic fiber is 0.1 to 3 parts by weight in terms of solids weight per 100 parts by weight of the synthetic fiber.

14. The method for producing a synthetic fiber cord for reinforcing an automobile hose according to any one of claims 11 to 13, characterized in that the synthetic fiber is a polyester fiber, and the hot stretch tension in the step of heat treatment after the adhesive treatment agent is applied is 0.3 to 2.5 cN / dtex, and the normalizing tension is 0.1 to 1.5 cN / dtex.

15. The method for producing a synthetic fiber cord for reinforcing an automobile hose according to any one of claims 11 to 13, characterized in that the synthetic fiber is a polyamide fiber, and the hot stretch tension in the step of heat treatment after the adhesive treatment agent is applied is 0.05 to 1 cN / dtex, and the normalizing tension is 0.05 to 1 cN / dtex.

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