Rubber-reinforcing fiber treatment agent, rubber-reinforcing fiber treatment agent set, method for producing rubber-reinforcing fiber, rubber-reinforcing fiber, and rubber product

Abstract

The purpose of the present invention is to provide: a fiber treatment agent for rubber reinforcement, which does not contain resorcinol or formaldehyde; a fiber treatment agent set for rubber reinforcement; and a fiber for rubber reinforcement, which has excellent adhesiveness with a rubber composition, and a rubber product. The present invention relates to a fiber treatment agent for rubber reinforcement, which does not contain resorcinol or formaldehyde and contains a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinylpyridine in a polymer molecule, and a blocked isocyanate compound.

Description

Technical Field

[0001] The present invention relates to a rubber reinforcing fiber treating agent free of resorcinol and formaldehyde, a rubber reinforcing fiber treating agent kit free of resorcinol and formaldehyde, a method for producing rubber reinforcing fiber using the kit, and rubber reinforcing fiber and rubber products obtained by using the products. Background Art

[0002] It is known that in conventional rubber products such as tires and power transmission belts that require high strength, by using rubber reinforcing fibers having resorcinol or a bonding composition comprising a resorcinol / formaldehyde initial condensate obtained by condensing resorcinol with formaldehyde, formaldehyde and rubber emulsion attached to the fiber surface made of polyester fibers or the like, high-strength rubber products with excellent bonding properties between the rubber reinforcing fibers and the rubber composition can be obtained.

[0003] It is also known that other adhesive compositions are used in combination with such an adhesive composition containing a resorcinol-formaldehyde initial condensate and a rubber emulsion. For example, Patent Documents 1 and 2 disclose an adhesive composition containing a water-soluble polymer, an organic polyisocyanate, an aqueous polyurethane compound, a thermoplastic polymer having a crosslinkable functional group, and an epoxy compound as an adhesive composition to be attached to the fiber before the adhesive composition containing a resorcinol-formaldehyde initial condensate and a rubber emulsion is attached to the fiber.

[0004] However, although formaldehyde is a raw material that effectively crosslinks resorcinol, it may be harmful to the human body and its usage needs to be reduced. Therefore, various attempts have been made to avoid using resorcinol and formaldehyde in adhesive compositions for rubber reinforcing fibers (Patent Documents 3 to 6).

[0005] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2001-98245 Patent Document 2: Japanese Patent Application Publication No. 2010-254928 Patent Document 3: International Publication No. 2014 / 091376 Patent Document 4: International Publication No. 2014 / 175844 Patent Document 5: International Publication No. 2015 / 188939 Patent Document 6: International Publication No. 2019 / 015792 Summary of the invention

[0006] Problems to be solved by the invention As attempts to avoid using resorcinol and formaldehyde, including avoiding using a resorcinol-formaldehyde initial condensate, Patent Documents 3 to 6 disclose impregnation compositions containing an acrylic polymer, an epoxy compound, a blocked isocyanate compound, and a rubber emulsion.

[0007] However, in these attempts not to use resorcinol and formaldehyde, it is not possible to obtain a high-strength rubber product having excellent adhesion between a rubber reinforcing fiber and a rubber composition, which is equivalent to that obtained by using a rubber reinforcing fiber having resorcinol attached thereto or an adhesive composition containing a resorcinol-formaldehyde initial condensate obtained by condensing resorcinol and formaldehyde, and formaldehyde and a rubber emulsion.

[0008] Therefore, an object of the present invention is to provide a rubber-reinforcing fiber-treating agent and a rubber-reinforcing fiber-treating agent set that do not contain resorcinol and formaldehyde, and provide a rubber-reinforcing fiber and a rubber product that are excellent in adhesion to a rubber composition.

[0009] Technical solutions to solve problems The above problems can be solved by a rubber reinforcing fiber treatment agent that does not contain resorcinol and formaldehyde, which is a rubber reinforcing fiber treatment agent comprising a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, and a blocked isocyanate compound. Among them, the rubber reinforcing fiber treatment agent preferably also contains a polymer compound having an oxazoline group. The polycarboxylic acid polymer contained in the rubber reinforcing fiber treatment agent is preferably a polymer having a cross-linked structure and contained in polycarboxylic acid polymer particles, or a polymer without a cross-linked structure. The above-mentioned polycarboxylic acid polymer particles are preferably microparticles with a volume average particle size of 10nm to 10μm.

[0010] In addition, the above-mentioned problem can be solved by a set of rubber reinforcing fiber treatment agents that do not contain resorcinol and formaldehyde, which is a rubber reinforcing fiber treatment agent set including a treatment agent 1 containing an epoxy compound and a blocked isocyanate compound, and a treatment agent 2 containing a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, a polycarboxylic acid polymer, and a high molecular compound having an oxazoline group. In addition, the problem can also be solved by a method for manufacturing rubber reinforcing fibers having the steps of using the rubber reinforcing fiber treatment agent set, causing a processing fluid containing the treatment agent 1 to adhere to the fiber, and then causing a processing fluid containing the treatment agent 2 to adhere to the fiber. Among them, the polycarboxylic acid polymer contained in the treatment agent 2 is preferably a polymer having a cross-linked structure and contained in polycarboxylic acid polymer particles, or a polymer without a cross-linked structure. The polycarboxylic acid polymer particles are preferably microparticles with a volume average particle size of 10nm to 10μm.

[0011] In addition, the above-mentioned problem can also be solved by attaching a bonding composition obtained by heating a composition containing a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, and a blocked isocyanate compound on the fiber surface. Or, the above-mentioned problem can be solved by attaching a bonding composition obtained by heating a composition containing a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, and a blocked isocyanate compound, and a polymer compound having an oxazoline group on the fiber surface. In addition, it can also be solved by a rubber product containing the above-mentioned rubber reinforcing fiber. Among them, the polycarboxylic acid polymer is preferably a polymer having a cross-linked structure and contained in polycarboxylic acid polymer particles, or a polymer without a cross-linked structure. The above-mentioned polycarboxylic acid polymer particles are preferably microparticles with a volume average particle size of 10nm to 10μm. The above-mentioned fiber preferably contains any one of polyester, nylon and aramid.

[0012] Effects of the Invention According to the present invention, a rubber-reinforcing fiber-treating agent and a rubber-reinforcing fiber-treating agent set containing no resorcinol and formaldehyde, a rubber-reinforcing fiber and a rubber product having excellent bonding performance with a rubber composition can be provided. DETAILED DESCRIPTION

[0013] The rubber reinforcing fiber treating agent of the present invention (hereinafter also referred to as "the treating agent of the present invention") comprises a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinylpyridine in the polymer molecule, and a blocked isocyanate compound, and does not contain resorcinol and formaldehyde.

[0014] The treatment agent of the present invention preferably further contains a polymer compound having an oxazoline group.

[0015] The polycarboxylic acid polymer contained in the treatment agent of the present invention is preferably a polymer having a crosslinked structure and contained in polycarboxylic acid polymer particles, or a polymer having no crosslinked structure. The polycarboxylic acid polymer particles are preferably fine particles having a volume average particle size of 10 nm to 10 μm.

[0016] The treatment agent of the present invention preferably further contains a liquid medium, or is preferably a liquid.

[0017] Rubber reinforcing fibers can be obtained by adhesion treatment of the fiber surface using the treatment agent of the present invention.

[0018] In addition, when the treatment agent of the present invention further contains a polymer compound having an oxazoline group, the treatment agent may be a treatment agent set containing both treatment agents.

[0019] The rubber reinforcing fiber treating agent set of the present invention (hereinafter also referred to as "the treating agent set of the present invention") comprises a treating agent 1 containing an epoxy compound and a blocked isocyanate compound, and a treating agent 2 containing a rubber emulsion having a structure derived from vinyl pyridine in a polymer molecule, a polycarboxylic acid polymer, and a high molecular compound having an oxazoline group, and does not contain resorcinol and formaldehyde.

[0020] The polycarboxylic acid polymer contained in the treatment agent 2 is preferably a polymer having a crosslinked structure and contained in polycarboxylic acid polymer particles, or a polymer having no crosslinked structure. The polycarboxylic acid polymer particles are preferably fine particles having a volume average particle diameter of 10 nm to 10 μm.

[0021] Both treatment agents 1 and 2 preferably further contain a liquid medium.

[0022] The rubber reinforcing fiber treatment agent and the rubber reinforcing fiber treatment agent set of the present invention do not contain resorcinol and formaldehyde. In the present invention, "does not contain resorcinol and formaldehyde" means that in addition to not containing resorcinol and formaldehyde, or substantially not containing both, it also substantially does not contain the resorcinol-formaldehyde initial condensate obtained by condensing resorcinol and formaldehyde. "Substantially free" of these compounds means that the content of each compound is less than 0.1% by mass. The content is preferably less than 0.01% by mass, and most preferably 0% by mass (undetectable).

[0023] The treating agent and treating agent set substantially free of resorcinol, formaldehyde, and a resorcinol-formaldehyde initial condensate of resorcinol and formaldehyde can be produced by using raw materials that substantially do not contain resorcinol, formaldehyde, and a resorcinol-formaldehyde initial condensate or that do not generate resorcinol, formaldehyde, and a resorcinol-formaldehyde initial condensate during the production process.

[0024] The liquid medium is preferably an aqueous medium. An aqueous medium refers to a liquid medium containing more than 50% by mass of water. As the water to be used, it is preferred to use pure water without impurities, but as long as the effect of the present invention can be achieved, industrial water or tap water etc. can also be used. In addition to water, the aqueous medium can also contain other liquid media. In addition to water, the liquid medium can also contain water-soluble organic solvents such as monohydric alcohols, polyols, glycol ethers, glycol esters, etc., and can be selected as needed based on low harmfulness, not easy to cause deterioration of the working environment due to volatile vapors etc.

[0025] Polycarboxylic acid polymers The polycarboxylic acid polymer used in the present invention refers to a polymer containing a structural unit derived from an unsaturated carboxylic acid monomer.

[0026] Unsaturated carboxylic acid monomers refer to monomers containing a carboxyl group (-COOH), a salt thereof or a carboxylic anhydride group (-CO-O-CO-) and a polymerizable carbon-carbon double bond. In the present invention, they refer to unsaturated carboxylic acids, salts thereof, and unsaturated carboxylic acid anhydrides. Specifically, unsaturated monocarboxylic acids and salts thereof such as acrylic acid, methacrylic acid, crotonic acid, α-hydroxyacrylic acid, and α-hydroxymethylacrylic acid; unsaturated dicarboxylic acids and salts thereof (which may be monosalts or disalts) such as fumaric acid, maleic acid, methyleneglutaric acid, and itaconic acid; unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride, etc. may be exemplified.

[0027] Examples of the above-mentioned salts include metal salts, ammonium salts, and organic amine salts. Examples of metal salts include salts of alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium, and transition metals such as iron and aluminum. Examples of organic amine salts include salts of alkylamines such as methylamine, n-butylamine, diethylamine, and triethylamine, alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, and dipropanolamine, and polyamines such as ethylenediamine and diethylenetriamine. Ammonium salts are salts formed with ammonium radicals.

[0028] In the polycarboxylic acid polymer used in the present invention, the structural unit derived from the unsaturated carboxylic acid monomer refers to a structural unit formed by polymerization of the unsaturated carboxylic acid monomer, specifically, a structure after the polymerizable carbon-carbon double bond of the unsaturated carboxylic acid monomer forms a single bond. For example, when the unsaturated carboxylic acid monomer is acrylic acid (CH2=CHCOOH), the structural unit derived from the unsaturated carboxylic acid monomer can be represented by -CH2-CH(COOH)-.

[0029] It should be noted that, in the present invention, the structural unit formed by a method other than polymerization of the unsaturated carboxylic acid monomer may also be included in the structural unit derived from the unsaturated carboxylic acid monomer, as long as it has the same structure as the structural unit derived from the unsaturated carboxylic acid monomer. The polycarboxylic acid polymer used in the present invention may contain one structural unit derived from the unsaturated carboxylic acid monomer, or may contain two or more.

[0030] The polycarboxylic acid polymer may contain a total of two or more carboxyl groups and / or salts thereof per molecule, or contain two or more carboxylic acid anhydride groups per molecule.

[0031] The polycarboxylic acid polymer used in the present invention may have a structural unit derived from a monomer other than the unsaturated carboxylic acid monomer (hereinafter also referred to as “other monomer”).

[0032] As other monomers, specific examples include, but are not particularly limited to, sulfonic acid monomers such as 3-allyloxy-2-hydroxypropanesulfonic acid, (meth)allylsulfonic acid, isoprenesulfonic acid, vinylsulfonic acid, styrenesulfonic acid and salts thereof; amino group-containing monomers such as vinylpyridine, vinylimidazole, dimethylaminoethyl (meth)acrylate, dimethylaminopropyl acrylate, aminoethyl methacrylate, diallylamine, diallyldimethylamine and quaternary compounds or quaternary ammonium salts thereof; nitrogen atom-containing monomers such as (meth)acrylonitrile; N-vinyl monomers such as N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylformamide, N-vinyl-N-methylacetamide, N-vinyloxazolidinone; (meth) Amide monomers such as 1,2-dihydroxypropane, 3-(meth)allyloxy-1,2-dihydroxypropane, (meth)allyl alcohol, and isoprene glycol; polyalkylene glycol monomers having a structure in which an alkylene oxide is added to the above unsaturated alcohol monomers; alkyl (meth)acrylate monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and dodecyl (meth)acrylate (among which, C (meth)acrylate is preferred) 1～10 Alkyl ester, more preferably (meth) acrylic acid C 1～5 (meth)acrylate-2-hydroxyethyl, (meth)acrylate-2-hydroxypropyl, (meth)acrylate-3-hydroxypropyl, (meth)acrylate-2-hydroxybutyl, (meth)acrylate-4-hydroxybutyl (meth)acrylate, and other hydroxyalkyl (meth)acrylate esters (among which, (meth)acrylate C 1～8 Hydroxyalkyl ester, more preferably (meth) acrylic acid C 1～4hydroxyalkyl esters), ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, trimethylolpropanol trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, Polymethacrylates such as dipentaerythritol hexamethacrylate, unsaturated glycidyl compounds such as (meth)allyl glycidyl ether and (meth) acrylate, monomers having a structure in which an alcohol is added to an unsaturated glycidyl compound such as 1-allyloxy-3-butoxypropane-2-ol, divinyl ether, diallyl ethers such as dialkylene glycol diallyl ether (diethylene glycol diallyl ether, dipropylene glycol diallyl ether, dibutylene glycol diallyl ether, etc.), polyalkylene glycol diallyl ether (polyethylene glycol diallyl ether, polypropylene glycol diallyl ether, polybutylene glycol diallyl ether, etc.), benzene Ethylene, alkyl styrenes (o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, ethylvinylbenzene, p-tert-butylstyrene, etc.), halogen-containing styrenes (o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.), vinyl aromatic monomers such as divinylbenzene, trivinylbenzene, divinylnaphthalene, indene, and vinylaniline, alkenyl-containing hydrocarbons such as isobutylene, 1,3-butadiene, octene, and trivinylcyclohexane, and carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate (among which, esters of saturated fatty acids and vinyl alcohol are preferred, and carbonyl groups having 1 to 5 carbon atoms are more preferred) esters of saturated fatty acids and vinyl alcohol), alkoxysilyl-containing silane coupling agents (vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tri(methoxyethoxy)silane, γ-(meth)acryloxypropyl trimethoxysilane, 2-phenylethyl trimethoxysilane, etc.), halogenated silane coupling agents (vinyl trichlorosilane, etc.), silanol-containing silane coupling agents (γ-(meth)acryloxypropyl hydroxysilane, γ-(meth)acryloxypropyl methylhydroxysilane, etc.), methacryloyl-modified polydimethylsiloxane and other silicon-containing monomers, etc. In addition, the above other monomers may be used alone or in combination of two or more.

[0033] In the polycarboxylic acid polymer used in the present invention, the structural unit derived from other monomers refers to a structural unit formed by polymerization of other monomers, specifically a structure in which the polymerizable carbon-carbon double bond possessed by other monomers forms a single bond. For example, in the case where the other monomer is butyl acrylate (CH2=CHCOOC4H9), the structural unit derived from other monomers can be represented by -CH2-CH(COOC4H9)-.

[0034] The polycarboxylic acid polymer used in the present invention may be a polymer having a cross-linked structure and contained in the polycarboxylic acid polymer particles, or a polymer without a cross-linked structure. A polymer without a cross-linked structure may also be a polymer contained in the polycarboxylic acid polymer particles having a cross-linked structure. It should be noted that in this specification, particles containing polycarboxylic acid polymers are also referred to as "polycarboxylic acid polymer particles". The polycarboxylic acid polymer particles containing polycarboxylic acid polymers having a cross-linked structure certainly have a cross-linked structure.

[0035] In the case where the polycarboxylic acid polymer is a polymer without a crosslinked structure, the structural unit derived from the unsaturated carboxylic acid monomer is preferably contained in an amount of 50 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less, and further preferably 90 mol% or more and 100 mol% or less, relative to 100 mol% of the total of the structural unit derived from the unsaturated carboxylic acid monomer and the structural unit derived from other monomers. By being within the above range, it is expected that the compounding stability of the rubber reinforcing fiber treatment agent will be improved.

[0036] In the case where the above-mentioned polycarboxylic acid polymer is a polymer without a cross-linked structure, relative to the total 100 mol% of the structural units derived from the unsaturated carboxylic acid monomer and the structural units derived from other monomers, the structural units derived from acrylic acid or acrylate preferably contain 50 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less, and further preferably 90 mol% or more and 100 mol% or less. By being within the above range, it is expected to improve the coordination stability of the fiber treatment agent for rubber reinforcement. The salt in the acrylate can exemplify the same salt as the above salt. The structural unit derived from acrylic acid or acrylate may contain only the structural unit derived from acrylic acid or only contain any one of the structural units derived from acrylate, may contain both, or may contain one or more of the structural units derived from acrylate.

[0037] The polycarboxylic acid polymer used in the present invention preferably contains neutralized carboxyl groups. That is, it is preferred that a part or all of the carboxyl groups contained in the polymer are in the form of salts of carboxyl groups.

[0038] The pH value of the aqueous solution of the polymer is preferably 3.5 to 10.0, more preferably 5.0 to 9.5, and even more preferably 6.0 to 9.0. Within the above range, the blending stability of the rubber reinforcing fiber treatment agent is expected to be improved. It should be noted that the pH value is a value measured by a glass electrode method.

[0039] In addition, the "salt" in the above-mentioned salt of a carboxyl group can be exemplified by the same salts as those in the above-mentioned salt of the unsaturated carboxylic acid-based monomer.

[0040] The polycarboxylic acid polymer preferably contains a structural unit derived from a metal salt of an unsaturated carboxylic acid and / or a structural unit derived from an organic amine salt of an unsaturated carboxylic acid and / or a structural unit derived from an ammonium salt of an unsaturated carboxylic acid. In the present invention, "a structural unit containing a metal salt derived from an unsaturated carboxylic acid" means a salt (e.g., -COO-X ﹢ .X ﹢ The metal salt may be, for example, the above-mentioned metal salt. Similarly, the "structural unit containing an organic amine salt derived from an unsaturated carboxylic acid" means a salt (for example, -COO-X ﹢ .X ﹢ Represents the state of organic amine cation). As the organic amine salt, for example, the above-mentioned organic amine salt can be exemplified. In addition, it can be, but is not particularly limited to, a salt formed with a primary amine, a salt formed with a secondary amine, a salt formed with a tertiary amine, a quaternary ammonium salt, etc. It can be a salt formed with an amine having only one amino group, or a salt formed with an amine having two or more amino groups, for example, it can also be a salt formed with a diamine, a salt formed with a triamine, and a salt formed with a polyamine, etc. As X in the above-mentioned organic amine salt, it is preferred that the molar ratio of nitrogen atoms to carbon atoms is 1:1 to 1:20, and more preferably 1:1 to 1:10. Similarly, "a structural unit containing an ammonium salt derived from an unsaturated carboxylic acid" means a state in which a salt of at least one carboxyl group contained in the structural unit derived from the unsaturated carboxylic acid and ammonium is formed.

[0041] In the above-mentioned polycarboxylic acid polymer, relative to the total 100 mol% of the structural units derived from the unsaturated carboxylic acid monomer and the structural units derived from other monomers, the total of the structural units derived from the metal salt of the unsaturated carboxylic acid, the structural units derived from the organic amine salt of the unsaturated carboxylic acid and the ammonium salt of the unsaturated carboxylic acid preferably contain more than 50 mol% and less than 100 mol%, more preferably more than 70 mol% and less than 100 mol%, and further preferably more than 90 mol% and less than 100 mol%. It can contain any one or more of the structural units derived from the metal salt of the unsaturated carboxylic acid and / or the organic amine salt of the unsaturated carboxylic acid and / or the ammonium salt of the unsaturated carboxylic acid, and it can also contain one or more respectively. More preferably, it is a structural unit containing an organic amine salt derived from an unsaturated carboxylic acid. By being within the above range, it is expected to improve the coordination stability of the fiber treatment agent for rubber reinforcement.

[0042] When the polycarboxylic acid polymer used in the present invention is a polymer without a crosslinking structure, the weight average molecular weight is preferably 500 or more and 100,000 or less, more preferably 1,500 or more and 80,000 or less, and further preferably 2,000 or more and 50,000 or less, in order to improve the compounding stability of the rubber reinforcing fiber treatment agent. The above-mentioned weight average molecular weight is a value measured by the measurement method described below.

[0043] It should be noted that since the polycarboxylic acid polymer particles having a cross-linked structure are water-insoluble / water-dispersible particles, the molecular weight of the polycarboxylic acid polymer cannot be measured. Water-insoluble means that the polycarboxylic acid polymer particles can maintain their particle shape when the solid content is less than 20% in water at a liquid temperature of 25°C.

[0044] The structural units in the polycarboxylic acid polymer used in the present invention may exist randomly or in a regular pattern such as in blocks.

[0045] The polycarboxylic acid polymer particles may have a uniform composition throughout the particles or may have different compositions in some parts. For example, the particles may have a core-shell structure including a core and a shell provided on the surface of the core (core-shell particles).

[0046] The content ratio of the shell part in the core-shell particles is preferably 10 mass % or more, more preferably 20 mass % or more, further preferably 30 mass % or more, particularly preferably 50 mass % or more in 100 mass % of the core-shell particles.

[0047] The polycarboxylic acid polymer particles preferably contain a polycarboxylic acid polymer in at least the surface layer. In the case of core-shell particles, preferably at least the shell contains a polycarboxylic acid polymer. In the case where the shell has multiple layers, preferably at least the outermost layer (the layer located on the surface side of the particle) contains a polycarboxylic acid polymer.

[0048] The content ratio of the polycarboxylic acid polymer in the polycarboxylic acid polymer particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 10% by mass or more, further preferably 20% by mass or more, further preferably 50% by mass or more, further preferably 70% by mass or more, and particularly preferably 90% by mass or more in 100% by mass of the particles.

[0049] In the case of core-shell particles, the content ratio of the polycarboxylic acid polymer in the shell part is preferably 50 mass % or more, more preferably 60 mass % or more, further preferably 80 mass % or more, particularly preferably 90 mass % or more in 100 mass % of the shell part.

[0050] The volume average particle size of the polycarboxylic acid polymer particles is preferably 10 nm to 10 μm, more preferably 50 nm to 5 μm, further preferably 100 nm to 1 μm, and particularly preferably 150 to 500 nm. When the volume average particle size is 10 nm to 10 μm, it is expected that the bonding performance between the rubber reinforcing fiber and the rubber composition in a high temperature environment will be significantly enhanced.

[0051] In the present invention, the volume average particle size is a value obtained by measuring the particle size distribution of a particle dispersion using a dynamic light scattering particle size distribution measuring apparatus and analyzing the particle size distribution based on normal distribution.

[0052] The method for producing the polycarboxylic acid polymer is not limited, but various conventionally known methods or combinations thereof can be exemplified. For example, the polycarboxylic acid polymer can be produced by a method including a step of polymerizing a monomer component having the unsaturated carboxylic acid monomer as an essential component (hereinafter, the step of polymerizing the monomer component is also referred to as a "polymerization step").

[0053] Alternatively, the polycarboxylic acid polymer particles may be produced by a method comprising a step of polymerizing a monomer component including a polymerizable monomer capable of generating a carboxyl group upon hydrolysis, and a step of hydrolyzing a precursor of the polymer obtained thereby. When the polycarboxylic acid polymer particles are produced by this method, the hydrolysis may be performed after the production of the particles containing the polymer precursor is completed in the polymerization step.

[0054] The polymerization method in the polymerization step can be, but is not particularly limited to, for example, solution polymerization, bulk polymerization, suspension polymerization, reverse suspension polymerization, or casting polymerization, film polymerization, spray polymerization, etc. In the case of manufacturing polycarboxylic acid polymer particles, the manufacturing method of known resin particles in the past, such as suspension polymerization, emulsion polymerization, etc., can be adopted. The situation other than this is preferably solution polymerization. In addition, the above-mentioned polymerization step can be carried out by batch mode or by continuous mode.

[0055] Examples of the polymerizable monomer capable of generating a carboxyl group by hydrolysis include unsaturated carboxylic acid esters and unsaturated carboxylic acid anhydrides.

[0056] As the unsaturated carboxylic acid ester, the ester of the above-mentioned unsaturated carboxylic acid (the ester of the above-mentioned unsaturated monocarboxylic acid, the monoester and diester of the above-mentioned unsaturated dicarboxylic acid) and the like can be exemplified. The compounds cited as the other monomers mentioned above can also be used. For example, esters of unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, α-hydroxyacrylic acid, α-hydroxymethylacrylic acid and the like; esters of unsaturated dicarboxylic acids such as fumaric acid, maleic acid, methyleneglutaric acid, itaconic acid (monoester, diester) and the like can be exemplified. More specifically, alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and dodecyl (meth)acrylate can be exemplified; (meth)acrylates containing an amino group such as dimethylaminoethyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, (meth)acrylate Hydroxyalkyl (meth)acrylates such as 2-hydroxypropyl acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; glycidyl (meth)acrylate; polymethacrylates; monomers containing silicon atoms such as γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropylhydroxysilane, γ-(meth)acryloxypropylmethylhydroxysilane, and methacryloyl-modified polydimethylsiloxane.

[0057] Examples of the unsaturated carboxylic acid anhydride include the above-mentioned maleic anhydride and itaconic anhydride.

[0058] Among them, the alkyl esters of the above-mentioned unsaturated carboxylic acids (alkyl esters of unsaturated monocarboxylic acids, alkyl esters of unsaturated dicarboxylic acids (monoalkyl esters and dialkyl esters) and the anhydrides of unsaturated carboxylic acids are preferred because the resulting polymer is easily hydrolyzed. The alkyl esters of the above-mentioned unsaturated carboxylic acids having 1 to 10 carbon atoms are more preferred. The alkyl esters of the above-mentioned unsaturated carboxylic acids having 1 to 5 carbon atoms are further preferred. The alkyl esters of the above-mentioned unsaturated carboxylic acids having 1 to 4 carbon atoms are further preferred. The alkyl esters of the above-mentioned unsaturated carboxylic acids having 1 or 2 carbon atoms are still more preferred. The alkyl esters of the above-mentioned unsaturated carboxylic acids having 1 carbon atoms are particularly preferred.

[0059] For the same reason, esters of unsaturated carboxylic acids having a hydrophilic group such as a hydroxyl group in the molecule, such as α-hydroxyacrylic acid and α-hydroxymethylacrylic acid, are also preferred.

[0060] In the polycarboxylic acid polymer, the total content of the structural units derived from the above-mentioned unsaturated carboxylic acid monomer and the above-mentioned polymerizable monomer that can be hydrolyzed to form a carboxyl group is preferably 0.1% by mass, more preferably 1% by mass or more, further preferably 10% by mass or more, further preferably 20% by mass or more, further preferably 50% by mass or more, further preferably 70% by mass or more, and particularly preferably 90% by mass or more in 100% by mass of the polymer.

[0061] When producing polycarboxylic acid polymer particles, it is preferred to use at least one crosslinkable monomer selected from the group consisting of divinylbenzene, 1,3-butadiene, diallyl ethers and polymethacrylates, among which divinylbenzene and 1,3-butadiene are more preferred, and divinylbenzene is even more preferred.

[0062] Specific examples of the polycarboxylic acid polymer in the polycarboxylic acid polymer particles include (meth)acrylic acid-ethylene glycol dimethacrylate copolymers, (meth)acrylic acid-triethylene glycol dimethacrylate copolymers, (meth)acrylic acid-trimethylolpropane trimethacrylate copolymers, (meth)acrylic acid-polyethylene glycol diallyl ether copolymers, (meth)acrylic acid-divinylbenzene copolymers, hydrolyzates of methyl acrylate-ethylene glycol dimethacrylate copolymers, hydrolyzates of methyl acrylate-triethylene glycol dimethacrylate copolymers, hydrolyzates of methyl acrylate-polyethylene glycol diallyl ether copolymers, hydrolyzates of methyl acrylate-divinylbenzene copolymers, hydrolyzates of methyl α-hydroxyacrylate-trimethylolpropane trimethacrylate copolymers, and hydrolyzates of methyl α-hydroxymethylacrylate-divinylbenzene copolymers.

[0063] When the polycarboxylic acid polymer particles are core-shell particles, the outermost layer of the shell part preferably contains the polycarboxylic acid polymer. The polymer constituting the core part may be exemplified by, but not particularly limited to, polymethyl methacrylate, polybutyl acrylate, polystyrene, methacrylic acid-styrene copolymer, methacrylic acid-butyl acrylate copolymer, and the like.

[0064] In the above-mentioned polymerization step, it is preferred to use a polymerization initiator when the polymerization is carried out. As the polymerization initiator, for example, hydrogen peroxide, persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate, azo compounds such as 2,2'-azobis(2-methylpropionic acid) dimethyl ester, 2,2'-azobis(isobutylnitrile), 2,2'-azobis(2-methylpropionamide) dihydrochloride, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamide] hydrate, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis(1-imino-1-pyrrolidinyl-2-methylpropane) dihydrochloride, and organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, di-tert-butyl peroxide, and cumene peroxide are preferably used. Among these polymerization initiators, hydrogen peroxide and persulfates are preferred, and persulfates are most preferred. These polymerization initiators can be used alone or in the form of a mixture of two or more thereof. The amount of the polymerization initiator used is preferably 0.1 g to 25 g, more preferably 0.1 g to 20 g, and even more preferably 0.1 g to 12 g, relative to 1 mol of the amount of the monomer (all monomers).

[0065] In the above polymerization step, a chain transfer agent may be used as needed. Specific examples of chain transfer agents include mercaptan chain transfer agents such as mercaptoethanol, thioglycolic acid, mercaptopropionic acid, and n-dodecyl mercaptan; halides such as carbon tetrachloride, dichloromethane, bromoform, and trichlorobromoethane; secondary alcohols such as isopropyl alcohol and glycerol; hypophosphorous acid (salts) such as hypophosphorous acid and sodium hypophosphite (including hydrates thereof); phosphorous acid (salts) such as phosphorous acid and sodium phosphite; sulfurous acid (salts) such as sodium sulfite and potassium sulfite; hydrogen sulfite (salts) such as sodium bisulfite and potassium bisulfite; dithionous acid (salts) such as sodium dithionite; pyrosulfite (salts) such as potassium pyrosulfite. The above chain transfer agents may be used alone or in the form of a mixture of two or more.

[0066] The amount of the chain transfer agent used is preferably 0 g or more and 20 g or less, more preferably 0 g or more and 15 g or less, and further preferably 1 g or more and 7 g or less, based on 1 mol of the monomers (all monomers) used.

[0067] In the above polymerization step, heavy metal ions may be used for the purpose of promoting the reaction. In the present invention, heavy metal ions refer to ions with a density of 4 g / cm 3By using heavy metal ions, the amount of polymerization initiator used can be reduced. The heavy metal ions are not particularly limited, as long as they are metals that can be contained in the form of ions, but due to excellent operability, it is preferred to use a solution in which a heavy metal compound is dissolved. Examples of the heavy metal compound include iron (II) sulfate ammonium hexahydrate, ferrous sulfate heptahydrate, ferrous chloride, ferric chloride, manganese chloride, and the like. The amount of the heavy metal ions used is preferably 0 ppm or more and 100 ppm or less, and more preferably 0 ppm or more and 50 ppm or less, relative to the total polymerization reaction solution.

[0068] In the above-mentioned polymerization step, a solvent is preferably used. As the solvent, water is preferably contained, and more preferably, the water content is 50% by mass or more and 100% by mass or less relative to the total solvent, and more preferably, the water content is 80% by mass or more and 100% by mass or less. As the solvent that can be used in the above-mentioned polymerization step, water, lower alcohols such as methanol, ethanol, and isopropanol, lower ketones such as acetone, butanone, and diethyl ketone, ethers such as dimethyl ether and dioxane, and amides such as dimethylformamide can be exemplified. These solvents can be used alone or in the form of a mixture of two or more.

[0069] The amount of the solvent used is preferably 40 to 400% by mass relative to 100% by mass of the monomer. It is more preferably 45% by mass or more, and further preferably 50% by mass or more. It is more preferably 350% by mass or less, and further preferably 300% by mass or less. When the amount of the solvent used is less than 40% by mass, the molecular weight of the resulting polymer may increase; and when it exceeds 400% by mass, the concentration of the resulting polymer may decrease, and the cost of storage and the like may be relatively high.

[0070] In the above polymerization step, the polymerization temperature is not particularly limited, and is preferably carried out at 0°C or above, and preferably at 150°C or below. It is more preferably at 40°C or above, further preferably at 60°C or above, and particularly preferably at 80°C or above. It is more preferably at 120°C or below, and further preferably at 110°C or below. The above polymerization temperature does not need to be always kept nearly constant during the polymerization reaction. For example, the polymerization can be started from room temperature, and the temperature can be raised to a set temperature with an appropriate heating time or heating rate, and then maintained at the set temperature. The temperature can also be changed over time (heating or cooling) during the polymerization reaction according to the dropwise addition method of the monomer components, initiator, etc.

[0071] The polymerization time in the polymerization step is not particularly limited, but is preferably 30 to 500 minutes when carried out in a batch method, for example.

[0072] The pressure in the reaction system in the above-mentioned polymerization step can be any situation under normal pressure (atmospheric pressure), under reduced pressure, or under pressure. From the perspective of the molecular weight of the obtained polymer, it is preferably carried out under normal pressure, or after the reaction system is sealed and under pressure. In addition, from the perspective of equipment such as a pressurizing device or a pressure reducing device, a pressure-resistant reaction vessel or a pipeline, it is preferably carried out under normal pressure (atmospheric pressure). As the environment in the reaction system, it can be an air environment or an inert gas environment. For example, the system can be replaced with an inert gas such as nitrogen before the polymerization starts.

[0073] The polycarboxylic acid polymer used in the present invention may be any polymer, and may be produced by steps other than the above-mentioned polymerization step, such as aging step, neutralization step, deactivation step of polymerization initiator or chain transfer agent, dilution step, drying step, concentration step, purification step, etc.

[0074] When a polycarboxylic acid polymer having a crosslinked structure contained in the polycarboxylic acid polymer particles is used, the polycarboxylic acid polymer has a crosslinked structure in addition to the structural units derived from the unsaturated carboxylic acid monomer, so that not only the adhesion between the rubber reinforcing fiber and the rubber composition is further improved, but also the adhesion between the rubber reinforcing fiber and the rubber composition in a high temperature environment is significantly increased. Excellent effect.

[0075] Since the polycarboxylic acid polymer contains a structural unit formed by polymerization of a hydrophilic unsaturated carboxylic acid monomer, it is generally a water-soluble polymer.

[0076] On the other hand, the polycarboxylic acid polymer having a cross-linked structure or the polycarboxylic acid polymer particles having a cross-linked structure are water-insoluble fine particles.

[0077] The polycarboxylic acid polymer having a crosslinked structure or the polycarboxylic acid polymer particles having a crosslinked structure can be made water-insoluble by, for example, adjusting the proportion of the structural unit constituting the crosslinked structure in the structural units constituting the polymer or the particles.

[0078] Epoxides Examples of the epoxy compound include glycidyl ethers such as ethylene glycol glycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, bisphenol A diglycidyl ether, bisphenol S diglycidyl ether, novolac glycidyl ether, and brominated bisphenol A diglycidyl ether; glycidyl esters such as hexahydrophthalic acid glycidyl ester and diol acid glycidyl ester; triglycidyl isocyanurate, glycidyl hydantoin, , tetraglycidyl diaminodiphenylmethane, triglycidyl p-aminophenol, triglycidyl m-aminophenol, diglycidyl aniline, diglycidyl toluidine, tetraglycidyl m-xylylenediamine, diglycidyl tribromoaniline, tetraglycidyl bisaminomethylcyclohexane and other glycidylamines; alicyclic or aliphatic epoxy compounds such as 3,4-epoxycyclohexylmethylcarboxylate, epoxidized polybutadiene, epoxidized soybean oil, etc. (excluding the polycarboxylic acid polymer used in the present invention). Among them, ethylene glycol glycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, which are compounds having good solubility in aqueous media, are preferred. As commercially available products, Denacol (registered trademark) series manufactured by Nagase Chemical Co., Ltd. are preferably used. In addition, only one of them can be used, or two or more can be used in combination.

[0079] Rubber emulsion having a structure derived from vinylpyridine in the polymer molecule The rubber emulsion having a structure derived from vinylpyridine in the polymer molecule is a preparation having properties in a state where a rubber component having a structure derived from vinylpyridine in the polymer molecule (excluding the polycarboxylic acid polymer and epoxy compound used in the present invention) is emulsified and dispersed in an aqueous medium.

[0080] The rubber component having a structure derived from vinylpyridine in the polymer molecule contains a polymer molecule of a copolymer of a rubber-forming monomer and vinylpyridine, and examples of the rubber-forming monomer include ethylene, propylene, butadiene, isoprene, isobutylene, styrene, etc. Among the copolymers, a vinylpyridine-styrene-butadiene copolymer is preferred.

[0081] As the vinylpyridine-styrene-butadiene copolymer preferably used in the present invention, it is preferred that the content ratio of the monomers used for polymerization is 0.5 to 30% by mass of vinylpyridine, 10 to 60% by mass of styrene, and 30 to 80% by mass of butadiene. It is also preferred to polymerize a monomer mixture containing 0.5 to 15% by mass of vinylpyridine, 30 to 60% by mass of styrene, and less than 60% by mass of butadiene, and then polymerize a monomer mixture containing 5 to 20% by mass of vinylpyridine, 10 to 40% by mass of styrene, and 45 to 75% by mass of butadiene to obtain a vinylpyridine-styrene-butadiene copolymer emulsion having a double bond structure. In addition, it may be a copolymer emulsion obtained by further polymerizing with monomers other than vinylpyridine, styrene, and butadiene.

[0082] It is also possible to use a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule and a rubber emulsion having no structure derived from vinyl pyridine in the polymer molecule. As the rubber emulsion having no structure derived from vinyl pyridine in the polymer molecule, natural rubber emulsion, styrene-butadiene copolymer rubber emulsion, carboxyl-modified styrene-butadiene copolymer rubber emulsion, nitrile rubber emulsion, chloroprene rubber emulsion, etc. can be exemplified. Among them, styrene-butadiene copolymer rubber emulsion, carboxyl-modified styrene-butadiene copolymer rubber emulsion, etc. are preferred. In the case of using two kinds of emulsions in combination, vinyl pyridine-styrene-butadiene copolymer rubber emulsion and styrene-butadiene copolymer emulsion are preferably used. In this case, the blending ratio of the two emulsions is preferably, but not particularly limited to, for example, the solid component mass ratio of vinyl pyridine-styrene-butadiene copolymer rubber emulsion to styrene-butadiene copolymer emulsion is 40:60 to 95:5, more preferably 60:40 to 90:10.

[0083] Blocked isocyanate compounds The blocked isocyanate compound is a compound having a blocked isocyanate group in the molecule (excluding the polycarboxylic acid polymer, epoxy compound and rubber component having a structure derived from vinylpyridine in the polymer molecule used in the present invention), which is obtained by, for example, an addition reaction of a known blocking agent with an isocyanate group of a known polyisocyanate compound. Specifically, it can be synthesized by, for example, reacting the following raw material components (a), (b) and, if necessary, (c).

[0084] (a) Polyisocyanate compounds (b) Capping agent (c) Compounds containing activated hydrogen (but excluding components (a) and (b) above) The blocked isocyanate compound preferably has a plurality of blocked isocyanate groups in the molecule.

[0085] Each raw material component will be described in more detail below.

[0086] (a) Polyisocyanate compound (hereinafter referred to as "polyisocyanate compound (a)").

[0087] The polyisocyanate compound (a) is not limited, but examples thereof include aromatic polyisocyanates, aromatic aliphatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and polyisocyanate derivatives including derivatives of these polyisocyanates.

[0088] Examples of the aromatic polyisocyanate include toluene diisocyanate (2,4-, 2,6-toluene diisocyanate or a mixture thereof) (TDI), phenylene diisocyanate (m-phenylene, p-phenylene diisocyanate or a mixture thereof), 4,4'-biphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), diphenylmethane diisocyanate (4,4'-, 2,4'- or 2,2'-diphenylmethane diisocyanate or a mixture of two or more thereof) (MDI), o-tolylene diisocyanate (TODI), and 4,4'-diphenyl ether diisocyanate.

[0089] Examples of aromatic aliphatic polyisocyanates include xylene diisocyanate (1,3- or 1,4-xylene diisocyanate or a mixture thereof) (XDI), tetramethylxylene diisocyanate (1,3-, 1,4-tetramethylxylene diisocyanate or a mixture thereof) (TMXDI), and ω,ω′-diisocyanate-1,4-diethylbenzene.

[0090] Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, 1,2-propylene diisocyanate, butane diisocyanate (tetramethylene diisocyanate, 1,2-butane diisocyanate, 2,3-butane diisocyanate or 1,3-butane diisocyanate), 1,5-pentane diisocyanate (PDI), 1,6-hexamethylene diisocyanate, and 2,6-diisocyanate methyl caproate.

[0091] Examples of the alicyclic polyisocyanate include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate or 1,3-cyclohexane diisocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate) (IPDI), methylenebis(cyclohexyl isocyanate) (4,4'-, 2,4'- or 2,2'-methylenebis(cyclohexyl isocyanate), Their trans, trans-isomers, trans, cis-isomers, cis, cis-isomers, or mixtures of two or more thereof) (H12MDI), methyl cyclohexane diisocyanate (methyl-2,4-cyclohexane diisocyanate or methyl-2,6-cyclohexane diisocyanate), norbornane diisocyanate (various isomers or mixtures of two or more thereof) (NBDI), bis(methyl isocyanate)cyclohexane (1,3- or 1,4-bis(methyl isocyanate)cyclohexane or mixtures thereof) (H6XDI), etc.

[0092] Examples of the polyisocyanate derivatives include polymers of the above-mentioned polyisocyanate (monomer) (e.g., dimers, trimers (e.g., isocyanurate-modified products, iminooxydiazinedione-modified products), pentamers, heptamers, etc.), allophanate-modified products (e.g., allophanate-modified products obtained by further adding isocyanate groups of the polyisocyanate (monomer) to carbamate groups formed by the reaction of the above-mentioned polyisocyanate (monomer) with a low molecular weight polyol described later), adducts (e.g., adducts (alcohol adducts) obtained by the reaction of the polyisocyanate (monomer) with a low molecular weight polyol described later), etc. ), biuret modified body (for example, biuret modified body generated by the reaction of the above-mentioned polyisocyanate (monomer) with water or amines, etc.), urea modified body (for example, urea modified body generated by further adding isocyanate groups of polyisocyanate (monomer) to urea groups formed by the reaction of the above-mentioned polyisocyanate (monomer) with diamines, etc.), oxadiazinetrione modified body (for example, oxadiazinetrione generated by the reaction of the above-mentioned polyisocyanate (monomer) with carbon dioxide, etc.), carbodiimide modified body (carbodiimide modified body generated by decarbonylation condensation reaction of the above-mentioned polyisocyanate (monomer), etc.), uretdione modified body, uretonimine modified body, etc. In addition, polymethylene polyphenyl polyisocyanate (crude MDI, polymeric MDI) and the like can also be exemplified.

[0093] The polyisocyanate compound (a) may be used alone or in combination of two or more. When two or more polyisocyanate compounds (a) are used in combination, in the production of blocked isocyanate, for example, the two or more polyisocyanate compounds may be reacted simultaneously, or blocked isocyanates obtained by using the respective polyisocyanate compounds may be mixed.

[0094] The polyisocyanate compound (a) is preferably an aliphatic polyisocyanate and its derivatives, an alicyclic polyisocyanate and its derivatives, or an aromatic polyisocyanate and its derivatives, because it can provide a rubber reinforcing fiber treating agent having excellent bonding strength between the rubber reinforcing fiber and the rubber composition.

[0095] (b) Capping agent (hereinafter referred to as "capping agent (b)") The blocking agent is a compound having the function of adding to the isocyanate group by addition reaction to inactivate (protect) the isocyanate group to form a blocked isocyanate group, and on the other hand, detaching (deprotecting) from the blocked isocyanate group by heating, etc. to form an isocyanate group again and restore the reaction activity. Examples of the blocking agent (b) include alcohol compounds, alkylphenol compounds, phenol compounds, active methylene compounds, thiol compounds, amide compounds, imide compounds, imidazole compounds, imidazoline compounds, pyrimidine compounds, guanidine compounds, triazole compounds, carbamic acid compounds, urea compounds, oxime compounds, amine compounds, imide compounds, imine compounds, pyrazole compounds, and hydrogen sulfite. Among them, amide compounds, active methylene compounds, oxime compounds, and pyrazole compounds are preferred, and ε-caprolactam, acetylacetone, diethyl malonate, butanone oxime, cyclohexanone oxime, 3-methylpyrazole, 3,5-dimethylpyrazole, etc. are more preferred. The end-capping agent (b) may be used alone or in combination of two or more.

[0096] (c) Compounds containing activated hydrogen (hereinafter referred to as "compounds containing activated hydrogen (c)") The compound (c) containing activated hydrogen is not limited, but various alcohols, polyols, and amines containing activated hydrogen can be exemplified.

[0097] The alcohols containing activated hydrogen are not limited, but examples thereof include polyether monools obtained by adding oxyalkylene groups (e.g., ethylene oxide, propylene oxide, butylene oxide, etc.) to methanol, ethanol, propanol, butanol, hexanol, octanol, etc. These alcohols containing activated hydrogen may be used alone or in combination of two or more.

[0098] The polyol containing activated hydrogen is not limited, but examples thereof include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2,2-trimethylpentanediol, 3,3-dihydroxymethylheptane, alkane (C7-20) diols, 1,3- or 1,4-cyclohexanediol or a mixture thereof, 1,3- or 1,4-cyclohexanediol or its mixture, hydrogenated bisphenol A, 1,4-dihydroxy-2-butene, 2,6-dimethyl-1-octene-3,8-diol, bisphenol A, diethylene glycol, triethylene glycol, dipropylene glycol and other diols; glycerol, trimethylolpropane, triisopropanolamine and other triols; tetramethylolmethane (pentaerythritol), diglycerol and other tetraols; xylitol and other pentaols; sorbitol, mannitol, allitol, iditol, galactitol, aloesin Hexavalent alcohols such as tropol, inositol, and dipentaerythritol; heptavalent alcohols such as mannoheptol; octavalent alcohols such as sucrose; random and / or block copolymers of polyoxyethylene glycol, polyoxyethylene triol, and oxyalkylene compounds such as ethylene oxide and propylene oxide (e.g., polyoxypropylene polyoxyethylene copolymer diol or triol, polyoxypropylene polyoxyethylene block polymer diol or triol, Pluronic (registered trademark) type polypropylene glycol or triol with ethylene oxide added to the end of polypropylene glycol, etc.), polyoxyethylene Polyether polyols such as bisphenol A ether, polyoxypropylene trimethylol propane ether, and polytetramethylene ether polyol; polyester polyols such as adipic acid polyester polyols, phthalic acid polyester polyols, and lactone polyester polyols; polycarbonate polyols, polyurethane polyols (polyether polyols, polyester polyols, polycarbonate polyols, etc. polyols modified with polyisocyanates), epoxy polyols, vegetable oil polyols, acrylic polyols, vinyl monomer modified polyols, etc. These polyols containing activated hydrogen can be used alone or in combination of two or more.

[0099] There are no particular limitations on the amine containing activated hydrogen, and specifically, diamines and polyamines can be used. Examples of diamines include ethylenediamine, trimethylenediamine, piperazine, and isophoronediamine. Examples of polyamines include diethylenetriamine, dipropylenetriamine, and triethylenetetramine. These amines containing activated hydrogen may be used alone or in combination of two or more.

[0100] Among these compounds containing activated hydrogen, hydrophilic compounds such as polyether monools, polyoxyethylene diols, polyoxyethylene triols, random and / or block copolymers of oxyalkylene compounds such as ethylene oxide and propylene oxide (e.g., polyoxypropylene polyoxyethylene copolymer diols or triols, polyoxypropylene polyoxyethylene block polymer diols or triols, polypropylene glycol terminal addition polymerization ethylene oxide Pluronic (registered trademark) type polypropylene glycol or triols, etc.) with ethylene oxide added to methanol, ethanol, propanol, butanol, hexanol, octanol, etc. can introduce hydrophilic groups (such as oxyethylene groups, etc.) into the molecular structure of the blocked isocyanate compound, thereby giving it self-emulsification (dispersibility in water), and are therefore preferred. In addition, anionic and cationic hydrophilic groups can also be used as hydrophilic groups. The number average molecular weight of these hydrophilic compounds is preferably 300 to 5000. These hydrophilic compounds can be used alone or in combination of two or more. In order to impart self-emulsification, the amount of these compounds introduced is preferably 1 mol% or more and 50 mol% or less, more preferably 40 mol% or less, and further preferably 30 mol% or less, based on the total amount of isocyanate groups used for the reaction.

[0101] The reaction conditions for synthesizing the blocked isocyanate compound are not particularly limited, but the blocked isocyanate compound can be synthesized, for example, under atmospheric pressure, under pressure, or under an inert gas (e.g., nitrogen, argon, etc.) environment at a reaction temperature of 0° C. to 150° C., preferably 30° C. to 100° C. The reaction time is, for example, 0.5 hours to 120 hours, preferably 1 hour to 72 hours.

[0102] Although the reaction can be carried out in the absence of a solvent during the synthesis, the reaction can also be carried out in ketones such as acetone, butanone, methyl isobutyl ketone, and cyclohexanone; nitriles such as acetonitrile; alkyl esters such as methyl acetate, ethyl acetate, butyl acetate, and isobutyl acetate; aliphatic hydrocarbons such as n-hexane, n-heptane, and octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; methyl cellosolve acetate, ethyl cellosolve acetate, methyl carbitol acetate, ethyl carbitol acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, 3-methyl-3-methoxybutyl acetate, ethyl The reaction is carried out in the presence of glycol ether esters such as 2-3-ethoxypropionate; ethers such as diethyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether; halogenated aliphatic hydrocarbons such as methyl chloride, dichloromethane, chloroform, carbon tetrachloride, methyl bromide, diiodomethane, dichloroethane; polar aprotic solvents such as N-methylpyrrolidone, dimethylformamide, N,N'-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphonamide; and known solvents such as propylene glycol-1-monomethyl ether-2-acetate. In addition, a synthesis catalyst can be used as needed.

[0103] By reacting the raw material components under such conditions, a part of the isocyanate groups of the polyisocyanate compound (a) can be reacted with the compound (c) containing activated hydrogen used as required to obtain a prepolymer in which unreacted isocyanate groups still remain. Thereafter, by allowing the blocking agent (b) to react with the obtained prepolymer, the remaining isocyanate groups are passivated to obtain a blocked isocyanate. In addition, the reaction sequence is not limited to the above, and for example, the blocking agent (b) can be reacted with the polyisocyanate compound (a) in a ratio that will leave unreacted isocyanate groups, and then reacted with the compound (c) containing activated hydrogen used as required to obtain a blocked isocyanate compound. It should be noted that the termination of the reaction can be determined by determining the concentration of isocyanate groups in the reaction solution measured, for example, according to the A method of JIS K1603-1:2007.

[0104] As described above, when a hydrophilic compound is used as a compound (c) containing activated hydrogen, a hydrophilic group can be introduced into the molecular structure of the blocked isocyanate compound, and self-emulsification (dispersibility in water) can be imparted. This self-emulsifying blocked isocyanate compound can be dispersed in the above-mentioned aqueous medium in the presence of an emulsifier as required, to form a water-dispersible blocked isocyanate. In addition, it is also possible to disperse the blocked isocyanate compound in an aqueous medium by applying a mechanical shear force to the blocked isocyanate compound as required in the presence of an emulsifier, etc., to obtain a water-dispersible blocked isocyanate. It should be noted that the blocked isocyanate compound as a dispersant has a solid state at room temperature or a liquid state at room temperature due to its chemical structure, so the names of the dispersed forms in these aqueous media are usually "suspension (suspension agent)" and "emulsion (emulsion)", but in the present invention, it is referred to as "water-dispersible blocked isocyanate" without distinction. As a method for obtaining a water-dispersible blocked isocyanate, there can be used, but not particularly limited to, a method of stirring and mixing a blocked isocyanate compound with water or the above-mentioned aqueous medium using a stirring device such as a homomixer, a homodispersor, a homogenizer, a magnetic stirrer, etc., a method of dispersing by high-speed stirring by filling glass beads, zirconia beads, etc. into a dispersing device such as a ball mill, a horizontal sand mixer, a vertical sand mixer, a grinder, a bead mill, etc. Then, in the case where the water-dispersible blocked isocyanate contains an unnecessary volatile organic solvent, the organic solvent can be volatilized and removed by, for example, reducing the pressure or heating under reduced pressure on the water-dispersible blocked isocyanate as needed.

[0105] In the water-dispersible blocked isocyanate thus obtained, the particle size of the dispersed particles of the blocked isocyanate compound is not limited but can be, for example, 10000 nm or less, preferably 1000 nm or less, more preferably 700 nm or less, further preferably 500 nm or less, and usually 50 nm or more in terms of volume average particle size. When the particle size of the dispersed particles of the blocked isocyanate compound is within this range, excellent dispersion stability can be ensured.

[0106] Furthermore, additives such as a dispersant and a defoaming agent may be appropriately added to the water-dispersible blocked isocyanate as required.

[0107] In addition, the blocked isocyanate compound of the present invention may be used alone or in combination of two or more.

[0108] Polymer compound having oxazoline group The treatment agent set of the present invention contains a polymer compound having an oxazoline group. The treatment agent of the present invention preferably contains a polymer compound having an oxazoline group in addition to a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, and a blocked isocyanate compound.

[0109] The polymer compound having an oxazoline group is a compound having an oxazoline group in the side chain of the polymer chain (excluding the polycarboxylic acid polymer, epoxy compound, rubber component having a structure derived from vinyl pyridine in the polymer molecule and blocked isocyanate compound used in the present invention). The compound acts as a crosslinking agent utilizing the reactivity of the oxazoline group. As the polymer chain, examples include acryl polymers, styrene-acryl copolymers, and copolymers grafted with polyoxyalkylene structures, and the number average molecular weight is preferably in the range of 5,000 to 300,000. As the polymer compound having an oxazoline group, it is preferred to use commercially available or known products, and as commercially available products, the EPOCROS (registered trademark) series manufactured by Nippon Shokubai Co., Ltd. can be exemplified.

[0110] The treatment agent of the present invention can be obtained by, for example, mixing a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, and a blocked isocyanate compound and a high molecular compound having an oxazoline group as required in an aqueous medium, and then adding the following additives as required, and supplementing the aqueous medium, etc. The mixing order and addition order of these materials can be appropriately adjusted. The treatment agent of the present invention can be directly used as a processing liquid used when performing an attachment treatment on the fiber, and can also be used as a processing liquid after being appropriately diluted from a high concentration stock solution state when performing the attachment treatment.

[0111] When the treatment agent of the present invention is used as a processing liquid for the attachment treatment of fibers, the concentration of the solid component (non-volatile components other than the aqueous medium) can be appropriately adjusted according to the processing method and the expected amount of solid component adhesion to the fibers, for example, to 0.1 to 50% by mass, preferably 1 to 30% by mass, and more preferably 5 to 25% by mass. The content ratio of each component in the solid component contained in the treatment agent of the present invention can be appropriately adjusted according to the type of fiber used, the composition of the rubber composition, the obtained bonding performance, etc. For example, the content of the rubber emulsion (solid component) having a structure derived from vinyl pyridine in the polymer molecule in the solid component is preferably 50 to 95% by mass, and the content of each of the epoxy compound (solid component) and the blocked isocyanate compound (solid component) is preferably 0.1 to 30% by mass.

[0112] From the viewpoint of bonding performance, the content ratio of the solid content of the polycarboxylic acid polymer contained in the treatment agent of the present invention is preferably 0.1 to 20% by mass of the total solid content contained in the treatment agent, more preferably 0.5 to 10% by mass, and even more preferably 1.0 to 5.0% by mass.

[0113] When the treatment agent of the present invention contains a polymer compound having an oxazoline group, the solid content thereof is preferably 0.01 to 5.0% by mass, more preferably 0.05 to 3.0% by mass, and even more preferably 0.1 to 1.0% by mass, based on the total solid content of the treatment agent from the viewpoint of bonding performance.

[0114] The treatment agent 1 contained in the treatment agent kit of the present invention can be obtained by, for example, mixing an epoxy compound and a blocked isocyanate compound in an aqueous medium, and then adding the following additives as needed, and then adding an aqueous medium. The treatment agent 2 contained in the treatment agent kit of the present invention can be obtained by, for example, mixing a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, a polycarboxylic acid polymer, and a high molecular compound having an oxazoline group in an aqueous medium, and then adding the following additives as needed, and then adding an aqueous medium. The mixing order and the addition order of these materials can be appropriately adjusted. The treatment agent 1 and the treatment agent 2 contained in the treatment agent kit of the present invention can be directly used as a processing liquid used when performing an attachment treatment on the fiber, and can also be used as a processing liquid after being appropriately diluted from a high concentration stock solution state when performing the attachment treatment.

[0115] When the treatment agent 1 is used as a processing liquid for the adhesion treatment of the fiber, the concentration of the solid component (non-volatile components other than the aqueous medium) can be appropriately adjusted according to the processing method and the expected amount of solid component adhesion to the fiber, for example, to 0.1 to 20% by mass, preferably 1 to 5% by mass. The content ratio of each component in the solid component contained in the treatment agent 1 can be appropriately adjusted according to the type of fiber used, the composition of the rubber composition, the obtained bonding performance, etc. For example, the content of the epoxy compound (solid component) in the solid component is preferably 10 to 90% by mass, and the content of the blocked isocyanate compound (solid component) is preferably 10 to 90% by mass.

[0116] When the treatment agent 2 is used as a processing liquid for the adhesion treatment of the fiber, the concentration of the solid component (non-volatile components other than the aqueous medium) can be appropriately adjusted according to the processing method and the expected amount of solid component adhesion to the fiber, for example, to 0.1 to 50% by mass, preferably 10 to 30% by mass. The content ratio of each component in the solid component contained in the treatment agent 2 can be appropriately adjusted according to the type of fiber used, the composition of the rubber composition, the obtained bonding performance, etc. For example, the content of the rubber emulsion (solid component) having a structure derived from vinylpyridine in the polymer molecule in the solid component is preferably 70 to 99% by mass.

[0117] In the treatment agent set of the present invention, the content ratio of the solid content of the polycarboxylic acid polymer is preferably 0.1 to 30% by mass of the total solid content contained in the treatment agent 2. It is more preferably 0.5 to 20% by mass, and further preferably 1.0 to 15% by mass.

[0118] In the treatment agent set of the present invention, the solid content of the polymer compound having an oxazoline group is preferably 0.01 to 5.0% by mass of the total solid content of the treatment agent 2. It is more preferably 0.05 to 5.0% by mass, and even more preferably 0.1 to 4.0% by mass.

[0119] The treatment agent and the treatment agent 1 and the treatment agent 2 of the treatment agent set of the present invention may further contain optional additives as long as they can produce the effects of the present invention. Examples of the additives include resin components other than the essential components of the present invention, crosslinking agents, surfactants, antioxidants, ultraviolet absorbers, pigments, metal powder pigments, rheology control agents, curing accelerators, plasticizers, flame retardants, antistatic agents, deodorants, antibacterial agents, etc.

[0120] The rubber reinforcing fiber of the present invention is attached to the fiber surface with a bonding composition obtained by heating a composition containing a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, and a blocked isocyanate compound. In another embodiment of the rubber reinforcing fiber of the present invention, the fiber surface is attached with a bonding composition obtained by heating a composition containing a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, and a blocked isocyanate compound, and a polymer compound having an oxazoline group. It should be noted that in the present invention, "bonding composition" refers to a composition that helps to show good bonding performance between the rubber reinforcing fiber and the rubber composition after being made into a final rubber product, but it itself does not necessarily have to have the adhesiveness of a bonding agent or adhesive. In addition, although the rubber emulsion has the performance of emulsifying and dispersing the rubber component in an aqueous medium as described above, in the bonding composition obtained by heating, the aqueous medium is volatilized and removed, so in the bonding composition, the rubber emulsion does not necessarily have to maintain this performance. When the composition before the heat treatment contains polycarboxylic acid polymer particles, it is not necessary to maintain the particle shape of the polycarboxylic acid polymer particles in the adhesive composition obtained by the heat treatment. In addition, since it is impossible to completely determine the structure of the "adhesive composition" at this stage, or it is difficult to determine the structure to an impractical degree, the invention of the rubber reinforcing fiber is characterized by the production method.

[0121] In addition, the rubber reinforcing fiber of the present invention further comprises the treating agent or treating agent set of the present invention, and preferably all treating agents used in its production process do not contain resorcinol and formaldehyde, and the bonding composition thereof does not contain resorcinol, formaldehyde, and components derived therefrom.

[0122] As the fiber used for rubber reinforcing fiber of the present invention, in the case of rubber products requiring high strength such as tires, power transmission belts, and high-pressure hoses, it is preferred that the organic fiber be twisted into a rope-like shape. In the case of sheet-like rubber products such as rubber sheets for buildings, the ropes can be arranged in a mesh shape, a fabric shape, etc. There is no limitation on the material of the organic fiber, but polyolefins such as nylon, polyester, aramid (aromatic polyamide), rayon, polypropylene and polyethylene, polycarbonate, polyacrylate, ABS resin, vinyl chloride resin, etc. can be exemplified. Among them, the fiber preferably includes any one or more of polyester, nylon and aramid, wherein, when polyester or aramid, which is relatively difficult to be joined to the rubber composition by conventional methods, is used, the effect of the present invention will be more significant. In addition, when the rubber reinforcing fiber used in the present invention contains aramid, the effect of the present invention will be more significant by using the synthetic montmorillonite described in Japanese Patent Publication No. 9-21073 and the carbon black described in Japanese Patent Publication No. 2009-127149 as additives contained in the treating agent and treating agent set of the present invention.

[0123] The rubber reinforcing fiber of the present invention can be manufactured by attaching a processing liquid containing the treatment agent of the present invention to the fiber, and then performing a drying treatment and a heating treatment. As the attachment treatment method, examples include dipping, brushing, casting, spraying, roller coating, blade coating, etc., among which dipping treatment is preferably adopted. The temperature during the drying treatment is preferably 60 to 200°C, and more preferably 80 to 150°C. The drying time is preferably 20 seconds to 10 minutes, and more preferably 30 seconds to 5 minutes. The temperature during the heating treatment is preferably 100 to 280°C, and more preferably 150 to 260°C. The heating time is preferably 20 seconds to 10 minutes, and more preferably 30 seconds to 5 minutes. A one-time treatment combining both drying treatment and heating treatment can also be performed. As the device used for the drying treatment and the heating treatment, a heating device using warm air, infrared rays, high-frequency waves, etc. can be used but is not particularly limited.

[0124] By manufacturing the rubber reinforcing fiber of the present invention in this way, the bonding composition generated from the components of the treatment agent of the present invention is attached to the fiber surface. The amount of the solid component of the bonding composition attached to the fiber can be appropriately adjusted according to the type of fiber used, the composition of the rubber composition, the required bonding properties, etc., and can be expressed as an attachment rate (the ratio of the mass of the solid component of the bonding composition attached to the mass of the fiber before treatment), for example, 1 to 20% by mass.

[0125] In the case of using the treatment agent set 1 of the present invention, the method for producing rubber reinforcing fibers of the present invention has a two-step process of first performing a treatment for attaching a processing liquid containing treatment agent 1 to the fibers, and then performing a treatment for attaching a processing liquid containing treatment agent 2 to the fibers. It is preferred that a drying treatment and a heating treatment are performed after the treatment for attaching the processing liquid containing treatment agent 1 and before the treatment for attaching the processing liquid containing treatment agent 2, and that a drying treatment and a heating treatment are also performed after the treatment for attaching the processing liquid containing treatment agent 2. The methods, apparatuses, conditions, etc. of the attachment treatment, the drying treatment, and the heating treatment are the same as those described above.

[0126] The rubber product of the present invention contains the rubber reinforcing fiber of the present invention. Such a rubber product is obtained by, for example, embedding the rubber reinforcing fiber of the present invention in unvulcanized rubber and vulcanizing the unvulcanized rubber to form a rubber composition, and the rubber composition and the rubber reinforcing fiber have excellent bonding properties. Such a rubber product itself can be a final product such as a tire, a power transmission belt, a hose, or a rubber sheet for buildings, or it can be a member for reinforcing a final rubber product in which the rubber composition is attached to the surface of the rubber reinforcing fiber to form a rope or sheet.

[0127] The rubber component contained in the rubber composition is not limited, but examples thereof include natural rubber (NR), polyisoprene rubber (IR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR) and other conjugated diene synthetic rubbers, ethylene-propylene copolymer rubber (EPM), ethylene-propylene-diene copolymer rubber (EPDM), polysiloxane rubber, etc. These rubber components may be used alone or in combination of two or more.

[0128] Examples of the vulcanizing agent used in the vulcanization treatment of the unvulcanized rubber include sulfur, polysulfide thiuram compounds such as tetramethylthiuram disulfide and dipentamethylenethiuram tetrasulfide, 4,4-dithiomorpholine, p-benzoquinone dioxime, p,p'-dibenzobenzoquinone dioxime, cyclic sulfimide, peroxide, etc. In addition, various compounding agents such as fillers such as carbon black, silica, and aluminum hydroxide, colorants, vulcanization accelerators, antioxidants, and softeners may be appropriately blended into the rubber composition.

[0129] The following contents are described in this manual.

[0130] The present invention (1) relates to a fiber-treating agent for rubber reinforcement, wherein the fiber-treating agent does not contain resorcinol and formaldehyde, and comprises a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinylpyridine in the polymer molecule, and a blocked isocyanate compound.

[0131] The present invention (2) is the rubber reinforcing fiber treating agent according to the present invention (1), further comprising a polymer compound having an oxazoline group.

[0132] The present invention (3) is the rubber reinforcing fiber treating agent according to the present invention (1) or (2), wherein the polycarboxylic acid polymer has a crosslinked structure and is contained in polycarboxylic acid polymer particles, or is a polymer without a crosslinked structure.

[0133] The present invention (4) is the rubber reinforcing fiber treating agent according to the present invention (3), wherein the polycarboxylic acid polymer particles are fine particles having a volume average particle size of 10 nm to 10 μm.

[0134] The present invention (5) relates to a set of rubber reinforcing fiber treatment agents, wherein the set is a rubber reinforcing fiber treatment agent set that does not contain resorcinol and formaldehyde, and includes a treatment agent 1 containing an epoxy compound and a blocked isocyanate compound, and a treatment agent 2 containing a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, a polycarboxylic acid polymer, and a high molecular compound having an oxazoline group.

[0135] The present invention (6) is the rubber reinforcing fiber treatment agent kit according to the present invention (5), wherein the polycarboxylic acid polymer has a cross-linked structure and is contained in polycarboxylic acid polymer particles, or is a polymer without a cross-linked structure.

[0136] The present invention (7) is the rubber reinforcing fiber treatment agent kit according to the present invention (6), wherein the polycarboxylic acid polymer particles are fine particles having a volume average particle size of 10 nm to 10 μm.

[0137] The present invention (8) relates to a method for producing a rubber reinforcing fiber, which comprises the steps of using the rubber reinforcing fiber treating agent set according to any one of the present inventions (5) to (7), subjecting the fiber to a treatment in which a processing liquid containing the treating agent 1 is attached, and then subjecting the fiber to a treatment in which a processing liquid containing the treating agent 2 is attached.

[0138] The present invention (9) relates to a rubber reinforcing fiber, wherein a bonding composition obtained by heating a composition containing a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, and a blocked isocyanate compound is attached to the fiber surface.

[0139] The present invention (10) relates to a rubber reinforcing fiber, wherein a bonding composition obtained by heating a composition containing a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, and a blocked isocyanate compound and a polymer compound having an oxazoline group is attached to the fiber surface.

[0140] The present invention (11) is the rubber reinforcing fiber according to the present invention (9) or (10), wherein the polycarboxylic acid polymer has a crosslinked structure and is contained in polycarboxylic acid polymer particles, or is a polymer without a crosslinked structure.

[0141] The present invention (12) is the rubber-reinforcing fiber according to (11), wherein the polycarboxylic acid polymer particles are fine particles having a volume average particle diameter of 10 nm to 10 μm.

[0142] The present invention (13) is the rubber-reinforcing fiber according to any one of the present inventions (9) to (12), wherein the fiber contains any one of polyester, nylon and aramid.

[0143] The present invention (14) relates to a rubber product comprising the rubber-reinforcing fiber according to any one of the present inventions (9) to (13).

[0144] Example The present invention is described in more detail below by way of examples, but the present invention is not limited to these examples. It should be noted that, in the present examples, "parts" means parts by mass, and "%" means % by mass, unless otherwise specified.

[0145] <Description of raw materials> (If the solid content concentration is not indicated, the concentration is 100%).

[0146] ·Denacol EX-313: Glycerol polyglycidyl ether, epoxy resin equivalent 141 g / eq, manufactured by Nagase Chemical Co., Ltd. Denacol EX-614: Sorbitol polyglycidyl ether, epoxy resin equivalent 167 g / eq, manufactured by Nagase Chemical Co., Ltd. · PYRATEX (registered trademark)-LB: Vinylpyridine-styrene-butadiene copolymer rubber emulsion, solid content concentration 38.8%, manufactured by Japan A & L Co., Ltd. Nipol (registered trademark) LX-112: Styrene-butadiene copolymer rubber emulsion, solid component concentration 41%, manufactured by Zeon Co., Ltd., Japan ·EPOCROS (registered trademark) K-2035E: Aqueous emulsion of a high molecular compound with styrene-acryl copolymer as the polymer main chain and oxazoline groups in the side chain, solid content concentration 40%, manufactured by Nippon Shokubai Co., Ltd. ·EPAN (registered trademark) 680: Pluronic (registered trademark) type nonionic surfactant, number average molecular weight 8750, ethylene oxide weight percentage 80%, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Neocol (registered trademark) P: dioctyl sulfosuccinate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Sumicanol (registered trademark) 700S: Resorcinol-formaldehyde initial condensate, solid component concentration 65%, manufactured by Sumitomo Chemical Co., Ltd. DM-6400: MDI type water-dispersible blocked isocyanate, solid component concentration 42%, regenerated isocyanate group (isocyanate group after the blocking agent is separated from the water-dispersible blocked isocyanate) concentration 7.90%, manufactured by Meisei Chemical Industry Co., Ltd. · SUMECTON (registered trademark)-ST: synthetic montmorillonite, manufactured by Kunimine Industries, Ltd. FUJI SP BLACK 203: Carbon black dispersion, solid content concentration 23.5%, manufactured by Fuji Color Co., Ltd.

[0147] <Measurement Conditions for Weight Average Molecular Weight of Polycarboxylic Acid Polymer> The weight average molecular weight of the polymer was measured using gel permeation chromatography (GPC) under the following conditions.

[0148] Device: HLC-8320GPC manufactured by Tosoh Corporation of Japan Detector: RI Chromatographic columns: TSKgel guardcolumn G3000PWXL (two pieces) manufactured by Tosoh Corporation of Japan were connected in sequence from the sample injection port.

[0149] Column temperature: 40°C Flow rate: 0.5ml / min Standard substances for drawing the calibration curve: sodium polyacrylate standard samples manufactured by American Polymer Standards Company (seven types with peak molecular weight (Mp) = 900 to 475,000) Calibration curve: cubic equation based on the Mp value and elution time of the above standard substances Eluent: 0.08M phosphate buffer <Measurement of pH Value of Polycarboxylic Acid Polymer> The pH value of the polymer was measured under the following conditions.

[0150] Device: pH METER D-52 manufactured by Horiba Manufacturing Co., Ltd. Electrode: Glass electrode Temperature: 25℃ <Measurement of Volume Average Particle Diameter of Polycarboxylic Acid Polymer> The aqueous dispersion of polycarboxylic acid polymer particles is diluted with ion-exchanged water to a polymer particle concentration of 0.01 to 0.05 mass %, and the volume average particle diameter (nm) of the polymer particles is determined by a dynamic light scattering method using a light scattering particle size distribution measuring apparatus (Zetasizer Ultra manufactured by Spectris Corporation).

[0151] <Preparation of polycarboxylic acid polymer> Production Example 1 Monoethanolamine and triethylamine were added to an aqueous solution of polyacrylic acid having a weight average molecular weight of 10,000, and the pH was adjusted to 7.0, followed by adjustment with pure water to obtain a polycarboxylic acid polymer composition of Production Example 1 having a solid content concentration of 53.0% containing a polycarboxylic acid polymer (1). It should be noted that the obtained polycarboxylic acid polymer is a polymer having no crosslinking structure, and since no undissolved matter was confirmed in the composition at a liquid temperature of 25° C., the polycarboxylic acid polymer (1) is water-soluble.

[0152] Production Example 2 Diethylamine and triethylamine were added to an aqueous solution of polyacrylic acid having a weight average molecular weight of 10,000, and the pH was adjusted to 7.0, followed by adjustment with pure water to obtain a polycarboxylic acid polymer composition of Production Example 2 having a solid content concentration of 53.5% containing a polycarboxylic acid polymer (2). It should be noted that the obtained polycarboxylic acid polymer is a polymer without a crosslinked structure, and since no undissolved matter was confirmed in the composition at a liquid temperature of 25° C., the polycarboxylic acid polymer (2) is water-soluble.

[0153] Production Example 3 In Production Example 1, diethanolamine was used instead of triethylamine, and the pH was adjusted to 7.2, and then adjusted with pure water to obtain a polycarboxylic acid polymer composition of Production Example 3 containing a polycarboxylic acid polymer (3) with a solid content concentration of 40.9%. It should be noted that the obtained polycarboxylic acid polymer is a polymer without a crosslinked structure, and since no undissolved matter was confirmed in the composition at a liquid temperature of 25° C., the polycarboxylic acid polymer (3) is water-soluble.

[0154] Production Example 4 Triethylamine was further added to the polycarboxylic acid polymer composition of Production Example 1, and the pH was adjusted to 7.2, and then the pH was adjusted with pure water to obtain a polycarboxylic acid polymer composition of Production Example 4 having a solid content concentration of 41.7% containing a polycarboxylic acid polymer (4). It should be noted that the obtained polycarboxylic acid polymer is a polymer without a crosslinked structure, and since no undissolved matter was confirmed in the composition at a liquid temperature of 25° C., the polycarboxylic acid polymer (4) is water-soluble.

[0155] Production Example 5 In Production Example 1, aqueous ammonia was used instead of triethylamine, and the pH was adjusted to 7.2, and then adjusted with pure water to obtain a polycarboxylic acid polymer composition of Production Example 5 containing a polycarboxylic acid polymer (5) having a solid content concentration of 45.1%. It should be noted that the obtained polycarboxylic acid polymer is a polymer without a crosslinked structure, and since no undissolved matter was confirmed in the composition at a liquid temperature of 25° C., the polycarboxylic acid polymer (5) is water-soluble.

[0156] Production Example 6 Monoethanolamine and diethanolamine were added to an aqueous solution of an acrylic acid-maleic acid copolymer having a weight average molecular weight of 10,000, and the pH was adjusted to 7.2, followed by adjustment with pure water to obtain a polycarboxylic acid polymer composition of Production Example 6 having a solid content concentration of 36.7% containing a polycarboxylic acid polymer (6). It should be noted that the obtained polycarboxylic acid polymer is a polymer without a crosslinked structure, and since no undissolved matter was confirmed in the composition at a liquid temperature of 25° C., the polycarboxylic acid polymer (6) is water-soluble.

[0157] Production Example 7 A polycarboxylic acid polymer composition of Production Example 7 having a solid content concentration of 16.6% and containing polycarboxylic acid polymer particles (RX-6-AQ-WA-2210 manufactured by Nippon Shokubai Co., Ltd.) composed of a polycarboxylic acid polymer (7) having a crosslinked structure (a hydrolyzate of α-hydroxymethylacrylate-divinylbenzene copolymer) was obtained. The particles had a uniform composition as a whole, a volume average particle diameter of 397 nm, and maintained their particle shape in an aqueous dispersion at a liquid temperature of 25°C.

[0158] Production Example 8 A polycarboxylic acid polymer composition of Production Example 8 was obtained, wherein the core contained an acryl-based polymer having no cross-linking structure (not belonging to the polycarboxylic acid polymer of the present invention) and the shell contained a polycarboxylic acid polymer (7) having a cross-linking structure (a hydrolyzate of α-hydroxymethylacrylate-divinylbenzene copolymer) (RX-6-AQ-WA-11210 manufactured by Nippon Shokubai Co., Ltd.) having a solid content concentration of 12.9%. The shell of the obtained polycarboxylic acid polymer particles had a cross-linking structure, the average particle size was 450 nm, and the particle shape was maintained in an aqueous dispersion at a liquid temperature of 25°C.

[0159] Production Example 9 A polycarboxylic acid polymer composition of Production Example 9 was obtained, wherein the core contained an acryl polymer having a cross-linked structure (not belonging to the polycarboxylic acid polymer of the present invention) and the shell contained a polycarboxylic acid polymer (7) having a cross-linked structure (a hydrolyzate of α-hydroxymethylacrylate-divinylbenzene copolymer) (RX-6-AQ-WA-51310 manufactured by Nippon Shokubai Co., Ltd.) having a solid content concentration of 18.1%. The core and shell of the polycarboxylic acid polymer particles had a cross-linked structure, the average particle size was 349 nm, and the particle shape was maintained in an aqueous dispersion at a liquid temperature of 25°C.

[0160] <Preparation of Water-Dispersible Blocked Isocyanate> Production Example 10 100 parts of 4,4'-diphenylmethane diisocyanate (isocyanate group content 0.800 mol), 100 parts of ε-caprolactam (NH group content 0.884 mol), and 200 parts of dioxane were added to a separable flask equipped with a stirrer, a cooling tube, and a thermometer. The liquid temperature was gradually raised and maintained at 85°C under continuous stirring. After reacting for 120 minutes, dioxane was removed to obtain a blocked isocyanate compound. Then, 100 parts of the blocked isocyanate compound and 10.7 parts of EPAN680 were added to 94.3 parts of water, and the mixture was finely dispersed using a wet micro-pulverizer to obtain a water-dispersible blocked isocyanate of Manufacturing Example 10 with a solid component concentration of 54%. The concentration of the regenerated isocyanate group (isocyanate group when the blocking agent is removed from the water-dispersible blocked isocyanate) of the water-dispersible blocked isocyanate of Manufacturing Example 10 was 8.60%.

[0161] <Preparation of rubber reinforcing fiber treating agent and rubber reinforcing fiber> Example 1-1 11.6 parts of Denacol EX-313 were added to 582.3 parts of water and dissolved uniformly. Next, 36.3 parts of the water-dispersible blocked isocyanate of Manufacturing Example 10 (19.6 parts of solid content) were added and mixed uniformly. Then 360.8 parts (140.0 parts of solid content) of PYRATEX-LB were added and mixed uniformly. Then 7.17 parts (3.8 parts of solid content) of the polycarboxylic acid polymer composition of Manufacturing Example 1 were added and mixed uniformly. Finally, 1.80 parts of EPOCROS K-2035E (0.56 parts of solid content) were added while slowly stirring and mixed uniformly to obtain the rubber reinforcement fiber treatment agent of Example 1-1 with a solid content concentration of 17.6%.

[0162] The rubber reinforcing fiber treatment agent of Example 1-1 thus obtained was used as a processing liquid as it is, and the fibers (polyester cord, HL wire, 1670 dtex, twisted pair) were impregnated, dried at 130°C for 2 minutes, and then heated at 240°C for 2 minutes to obtain the rubber reinforcing fiber of Example 1-1 with the adhesive composition attached to the fiber surface. The amount of solid component of the adhesive composition attached to the fiber was 10.4% in terms of the attachment rate (the ratio of the mass of the solid component of the attached adhesive composition to the mass of the fiber before the treatment).

[0163] Examples 1-2 to 1-14, Comparative Examples 1-1 to 1-4 The same method as in Example 1-1 was carried out, except that the raw materials and fibers (polyester rope is represented by "PET" and nylon rope (1400 dtex, twisted pair) is represented by "Ny") used in the rubber reinforcing fiber treatment agent were replaced by the materials and amounts described in Tables 1 and 2, to obtain rubber reinforcing fiber treatment agents and rubber reinforcing fibers of Examples 1-2 to 1-14 and Comparative Examples 1-1 to 1-4.

[0164] Reference Example 1: 300.7 parts of PYRATEX-LB (116.7 parts of solid content) and 125.0 parts of Nipol LX-112 (51.3 parts of solid content) were added to 384.7 parts of water and mixed uniformly to obtain an emulsion dilution. On the other hand, 7.0 parts of a 10% sodium hydroxide aqueous solution were added to 126.5 parts of water and mixed, and 45.0 parts (29.3 parts of solid content) of Sumicanol700S were added and dissolved uniformly to obtain a resorcinol-formaldehyde initial condensate solution. Then, while slowly stirring the emulsion dilution, the resorcinol-formaldehyde initial condensate solution was added thereto, and 11.1 parts of formalin (37% aqueous solution) was added and mixed uniformly to obtain a rubber reinforcing fiber treatment agent with a solid content concentration of 20.0%. The rubber reinforcing fiber treatment agent was used as a processing liquid, and the fiber (nylon rope, 1400 dtex, twisted pair) was impregnated, dried at 130°C for 2 minutes, and then heated at 240°C for 2 minutes to obtain a rubber reinforcing fiber with an adhesive composition attached to the fiber surface. The solid content of the adhesive composition attached to the fiber was 7.2% in terms of the attachment rate.

[0165] <Preparation and Evaluation of Rubber Products> 70 parts of natural rubber, 30 parts of styrene-butadiene copolymer rubber, 60 parts of carbon black powder, 4 parts of zinc oxide powder, 1.5 parts of stearic acid, 8 parts of aromatic oil, 2.5 parts of sulfur, and 1.1 parts of vulcanization accelerator (N-cyclohexyl-2-benzothiazolylsulfonamide) were fully kneaded and formed into a sheet to make an unvulcanized rubber sheet. The 7 rubber reinforcing fibers of Example 1-1 were buried near the surface of the unvulcanized rubber sheet, and vulcanized at a temperature of 150°C for 30 minutes at a pressing pressure of 4.7 MPa to form a sheet with the rubber composition attached to the rubber reinforcing fibers, and the rubber product of Example 1-1 was obtained. Rubber products were also obtained in the same manner for each rubber reinforcing fiber of Examples 1-2 to 1-14, Comparative Examples 1-1 to 1-4, and Reference Example 1.

[0166] Bonding strength evaluation Using a precision universal testing machine (Autograph (registered trademark) AG-X, manufactured by Shimadzu Corporation), a flat gripper was used to leave the two ends of the rope and fix the five ropes. The ropes were peeled off at a speed of 300 mm / min in a direction 90 degrees relative to the surface of the rubber sheet, and the force required at that time was measured. The measured value was divided by 5 (the force per rope) as the joint strength. When the joint strength is 17N or more, it can be used for practical applications. The results are shown in Tables 1 and 2.

[0167] Evaluation of rubber adhesion In the above-mentioned bonding strength evaluation, the surface of the rubber reinforcing fiber peeled off from the rubber sheet was visually observed and evaluated according to the following criteria. When the rubber adhesion amount was "○" or "◎", it can be used for practical application. The results are shown in Tables 1 and 2.

[0168] ◎: The amount of the black rubber composition attached is large, and there is no portion where the rope is visible.

[0169] ○: Although the amount of the black rubber composition adhered was large, there was a portion where a portion of the rope was visible.

[0170] Δ: The amount of the black rubber composition adhered as a whole is small, and there are many portions where the ropes are visible.

[0171] ×: There is no or almost no adhesion of the black rubber composition.

[0172] Evaluation of heat-resistant bonding strength Rubber reinforcing fibers of Examples 1-7, 1-10, and Comparative Example 1-1 were produced again, and the amount of solid content of the adhesive composition attached to the fibers was evaluated again.

[0173] For the rubber products obtained from the rubber reinforcing fibers in the same manner as above, the heat-resistant bonding strength was evaluated in the same manner as the evaluation of the bonding strength, except that the heat-resistant bonding strength was measured in an environment of 120°C after heating in a heating chamber at 120°C for 5 minutes. When the heat-resistant bonding strength is 4.5N or more, it can be used for practical applications. The results are shown in Table 3.

[0174] Evaluation of heat-resistant rubber adhesion In the evaluation of the heat-resistant bonding strength, in addition to visually observing the surface of the rubber reinforcing fiber peeled off from the rubber sheet, the heat-resistant rubber adhesion was evaluated in the same manner as the evaluation of the rubber adhesion. When the heat-resistant rubber adhesion was "△", "○", or "◎", it can be used for practical application. The results are shown in Table 3.

[0175] [Table 1]

[0176] [Table 2]

[0177] [Table 3]

[0178] <Rubber-reinforcing fiber treatment agent set and preparation of rubber-reinforcing fiber> Example 2-1 13.3 parts of Denacol EX-614 and 0.7 parts of Neocol P were added to 973.6 parts of water and uniformly dissolved, and then 12.4 parts of the water-dispersible blocked isocyanate of Manufacturing Example 10 (6.7 parts of solid content) were added and uniformly mixed to obtain a treatment agent 1 with a solid content concentration of 2.07%. In addition, 484.5 parts of PYRATEX-LB (188.3 parts of solid content) were added to 484.3 parts of water and uniformly mixed. Then 23.72 parts (9.7 parts of solid content) of the polycarboxylic acid polymer composition of Manufacturing Example 3 were added and uniformly mixed. Finally, 7.40 parts of EPOCROS K-2035E (2.96 parts of solid content) were added while slowly stirring and uniformly mixed to obtain a treatment agent 2 with a solid content concentration of 20.1%. The obtained treatment agent 1 and treatment agent 2 were used to prepare the rubber reinforcing fiber treatment agent set of Example 2-1.

[0179] The processing agent 1 of the rubber reinforcing fiber processing agent set of Example 2-1 thus obtained was used as a processing liquid, and the fibers (polyester rope, HL wire, 1670 dtex, twisted pair) were impregnated, dried at 130°C for 2 minutes, and then heated at 240°C for 2 minutes. Then, the processing agent 2 of the rubber reinforcing fiber processing agent set of Example 2-1 was used as a processing liquid, and the treated fibers were impregnated with the processing agent 1, dried at 130°C for 2 minutes, and then heated at 240°C for 2 minutes to obtain the rubber reinforcing fiber of Example 2-1 with the bonding composition attached to the fiber surface. The solid content of the bonding composition attached to the fiber was 7.1% in terms of the attachment rate.

[0180] Examples 2-2 to 2-8, Comparative Example 2-1 The same method as in Example 2-1 was followed except that the raw materials used in the rubber reinforcing fiber treatment agent were replaced with the species and amounts listed in Table 4 to obtain rubber reinforcing fiber treatment agent sets and rubber reinforcing fibers of 2-2 to 2-8 and Comparative Example 2-1. All fibers were polyester cords.

[0181] Reference Example 2 13.3 parts of Denacol EX-614 and 0.7 parts of Neocol P were added to 973.6 parts of water and uniformly dissolved. Then, 12.4 parts of the water-dispersible blocked isocyanate of Manufacturing Example 10 (6.7 parts of solid content) were added and uniformly mixed to obtain a pretreatment agent with a solid content concentration of 2.07%. In addition, 300.7 parts of PYRATEX-LB (116.7 parts of solid content) and 125.0 parts of Nipol LX-112 (51.3 parts of solid content) were added to 384.7 parts of water and uniformly mixed to prepare an emulsion dilution. On the other hand, 7.0 parts of a 10% sodium hydroxide aqueous solution were added to 126.5 parts of water and mixed, and 45.0 parts of Sumicanol700S (29.3 parts of solid content) were added and uniformly dissolved to obtain a resorcinol-formaldehyde initial condensate solution. Next, the emulsion dilution was slowly stirred while adding the resorcinol-formaldehyde initial condensate solution thereto, and then 11.1 parts of formalin (37% aqueous solution) was added and mixed evenly to obtain a post-treatment agent having a solid component concentration of 20.0%. The obtained pre-treatment agent and post-treatment agent were used to form a rubber reinforcing fiber treatment agent set of Reference Example 2. The processing conditions of the polyester rope were the same as those of Example 2-1 (treatment agent 1 was replaced by the pre-treatment agent, and treatment agent 2 was replaced by the post-treatment agent), and a rubber reinforcing fiber was obtained.

[0182] Examples 2-9, 2-10, Reference Examples 3, 4 The rubber reinforcing fiber treatment agent sets and rubber reinforcing fibers of Examples 2-9, 2-10, and Reference Examples 3 and 4 were obtained in the same manner as in Example 2-1 or Reference Example 2, except that the raw materials used in the rubber reinforcing fiber treatment agent were replaced with the materials and amounts described in Table 6. Aramid cords (1110 dtex, twisted pair, indicated as "Ara" in the table) were used as the fibers.

[0183] <Preparation and Evaluation of Rubber Products> Using each rubber reinforcing fiber obtained, a rubber product was prepared in the same manner as in Example 1-1, and the bonding strength and rubber adhesion amount were evaluated in the same manner as in Example 1-1. The results are shown in Tables 4 and 6. In the same manner as in Examples 1-7, 1-10, and Comparative Example 1-1, the bonding composition of each rubber reinforcing fiber and each rubber product of Examples 2-1, 2-6, Comparative Example 2-1, and Reference Example 2 was evaluated for the solid component adhesion amount on the fiber, the heat-resistant bonding strength, and the heat-resistant rubber adhesion amount. The results are shown in Table 5.

[0184] [Table 4]

[0185] [Table 5]

[0186] [Table 6]

[0187] From the results of Tables 1 to 6, it can be seen that in the rubber products containing rubber reinforcing fibers obtained by using the rubber reinforcing fiber treatment agent or the rubber reinforcing fiber treatment agent set of the present invention, the bonding strength between the rubber reinforcing fibers and the rubber composition is excellent, and the amount of rubber adhesion reflecting the toughness of the interface between the rubber reinforcing fibers and the rubber composition is also large. In addition, according to the results of Tables 3 and 5, the polycarboxylic acid polymer contained in the rubber reinforcing fiber treatment agent or the rubber reinforcing fiber treatment agent set of the present invention has a cross-linked structure and is contained in the polycarboxylic acid polymer particles. Thus, the rubber products containing rubber reinforcing fibers obtained by using these raw materials have excellent bonding strength between the rubber reinforcing fibers and the rubber composition under high temperature environment, and the amount of rubber adhesion reflecting the toughness of the interface between the rubber reinforcing fibers and the rubber composition is also large.

Claims

1. A rubber reinforcing fiber treating agent, characterized in that: It is a fiber treatment agent for rubber reinforcement that does not contain resorcinol and formaldehyde. Contains a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinylpyridine in the polymer molecule, and a blocked isocyanate compound.

2. The rubber reinforcing fiber treating agent according to claim 1, characterized in that It also contains high molecular weight compounds having an oxazoline group.

3. The rubber reinforcing fiber treating agent according to claim 1 or 2, characterized in that: The polycarboxylic acid polymer has a cross-linked structure and is contained in polycarboxylic acid polymer particles, or is a polymer without a cross-linked structure.

4. The rubber reinforcing fiber treating agent according to claim 3, characterized in that The polycarboxylic acid polymer particles are microparticles having a volume average particle diameter of 10 nm to 10 μm.

5. A rubber reinforcing fiber treatment agent kit, characterized in that: The invention discloses a set of fiber treatment agents for rubber reinforcement that do not contain resorcinol and formaldehyde, comprising a treatment agent 1 containing an epoxy compound and a blocked isocyanate compound, and a treatment agent 2 containing a rubber emulsion having a structure derived from vinyl pyridine in the polymer molecule, a polycarboxylic acid polymer, and a high molecular compound having an oxazoline group.

6. The rubber reinforcing fiber treatment agent kit according to claim 5, characterized in that: The polycarboxylic acid polymer has a cross-linked structure and is contained in polycarboxylic acid polymer particles, or is a polymer without a cross-linked structure.

7. The rubber reinforcing fiber treatment agent kit according to claim 6, characterized in that: The polycarboxylic acid polymer particles are microparticles having a volume average particle diameter of 10 nm to 10 μm.

8. A method for producing a rubber reinforcing fiber, characterized in that: The method comprises the steps of using the rubber reinforcing fiber treating agent set according to any one of claims 5 to 7, subjecting the fibers to a treatment in which a processing liquid containing the treating agent 1 is attached, and then subjecting the fibers to a treatment in which a processing liquid containing the treating agent 2 is attached.

9. A rubber reinforcing fiber, characterized in that: The adhesive composition obtained by heat-treating a composition containing a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinylpyridine in the polymer molecule, and a blocked isocyanate compound is attached to the fiber surface.

10. A rubber reinforcing fiber, characterized in that: The adhesive composition obtained by heating a composition containing a polycarboxylic acid polymer, an epoxy compound, a rubber emulsion having a structure derived from vinylpyridine in the polymer molecule, a blocked isocyanate compound, and a high molecular compound having an oxazoline group is attached to the fiber surface.

11. The rubber reinforcing fiber according to claim 9 or 10, characterized in that: The polycarboxylic acid polymer has a cross-linked structure and is contained in polycarboxylic acid polymer particles, or is a polymer without a cross-linked structure.

12. The rubber reinforcing fiber according to claim 11, characterized in that The polycarboxylic acid polymer particles are microparticles having a volume average particle diameter of 10 nm to 10 μm.

13. The rubber reinforcing fiber according to claim 9 or 10, characterized in that: The fiber contains any of polyester, nylon and aramid.

14. A rubber product, characterized in that: Contains the rubber reinforcing fiber according to claim 9 or 10.

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