Adhesive composition for organic fibers, organic fiber-rubber composite, and tire

Abstract

The present invention addresses the problem of providing an adhesive composition for organic fibers which is reduced in environmental burden, has satisfactory application efficiency, and can bring about satisfactory adhesion between the organic fibers and a coating rubber composition. The adhesive composition for organic fibers is characterized by comprising (A) a latex of a rubber including an unsaturated diene, (B) a polypeptide, and at least one compound selected from the group consisting of (C) a water-compatible compound having a (thermally dissociable blocked) isocyanate group, (D) an epoxide compound, and (E) a polyphenol, and by containing no resorcinol.

Description

[Technical Field]

[0001] The present invention relates to an adhesive composition for organic fibers, an organic fiber-rubber composite, and a tire. [Background technology]

[0002] Conventionally, for the purpose of reinforcing rubber products such as tires, organic fibers such as tire cords made of nylon fibers, polyester fibers, etc. have been bonded to a rubber composition for tires to form an organic fiber-rubber composite. A commonly used technique for the bonding is to coat organic fibers (particularly organic fiber cords) with an adhesive composition for organic fibers, embed them in the rubber composition for tires, and co-vulcanize them with the rubber composition for tires.

[0003] In addition, in the step of coating the organic fiber cord with the adhesive composition for organic fibers, a solvent is generally used to adjust the viscosity of the adhesive composition for organic fibers, but since the solvent volatilizes in the step, it is preferable to use water, which has a low environmental impact, as the solvent. Furthermore, when coating with the adhesive composition for organic fibers by immersion, it is necessary to lower the viscosity of the adhesive composition for organic fibers to a level that allows it to be applied by immersion.

[0004] In general, components contained in aqueous adhesive compositions that are water-soluble (water-soluble or water-dispersible) must have a polar molecular structure. However, polymeric materials such as rubber and organic fiber substrates that serve as adherends have low polarity, and adhesion becomes difficult when the polarity of the surface of the rubber or organic fiber substrate differs greatly from the polarity of the components contained in the adhesive composition for organic fibers. Therefore, in order to use the aqueous adhesive composition as an adhesive composition for organic fibers, the components contained in the aqueous adhesive composition must have polarity because they are aqueous. However, this polarity must be controlled so that a difference in polarity with the adherend does not result in a decrease in adhesion. Therefore, aqueous adhesive compositions for organic fibers that can achieve both of these tradeoffs are preferably used.

[0005] Here, with regard to the step of coating the organic fiber cord with the adhesive composition for organic fibers, an example of a step in which the organic fiber cord is immersed in the adhesive composition for organic fibers will be described with reference to FIG. 1.

[0006] The organic fiber cord 1 is unwound and runs into a dipping bath 3 containing an adhesive composition 2 for organic fibers, where it is immersed in the adhesive composition 2. The organic fiber cord 4 coated with the adhesive composition 2 for organic fibers is then lifted out of the dipping bath 3, and excess adhesive composition 2 for organic fibers is removed by a squeeze roll 5. The organic fiber cord 4 coated with the adhesive composition 2 for organic fibers is then transported by the rolls, dried in a drying zone 6, heat-cured in a hot zone 7 while applying tension to stretch the cord, and heat-cured in a normalization zone 8 while precisely adjusting the tension to achieve the desired strength and elongation properties (normalizing). After air-cooling outside the zones, the organic fiber cord 4 coated with the adhesive composition 2 for organic fibers is wound up. In this way, the organic fiber cord is coated with the adhesive composition for organic fibers.

[0007] As the adhesive composition for organic fibers, RFL (resorcinol-formaldehyde-latex) adhesive compositions obtained by maturing a mixed liquid containing resorcinol, formaldehyde, and rubber latex, or adhesive compositions obtained by mixing a specific adhesion promoter into the RFL adhesive composition have conventionally been used (see Patent Documents 1 to 4).

[0008] As is well known, in the rubber industry, an adhesive composition (Patent Document 1) consisting of a water-dispersible rubber latex component and an aqueous phenolic resin obtained by mixing and maturing water-soluble resorcinol and formaldehyde has been found to have the function of both bonding to the rubber substrate and bonding to the surface of a substrate with low polarity, such as an organic fiber cord material, and is therefore widely used worldwide. In bonding using the RFL adhesive composition, the rubber latex component contained in the RFL adhesive composition bonds to the rubber substrate by co-vulcanization, while the phenolic resin component consisting of a condensate of resorcinol and formaldehyde, which has adhesive properties with organic fiber substrates, bonds to the substrate.

[0009] The reason why resorcinol is preferably used here is that it provides a phenolic condensation resin, which is a resin type that has high adhesion to the substrate, and the polar functional group introduced into the phenol ring to obtain water solubility is a hydroxyl group, which has relatively low polarity and is unlikely to cause steric hindrance, and therefore it can provide a resin component that has high adhesion to the organic fiber substrate.

[0010] The RFL adhesive composition is obtained by mixing and maturing resorcinol, formaldehyde, and a rubber latex that uses rosin acid or the like as an emulsifier during polymerization in the presence of a basic composition. It is presumed that this causes the water-dissolved resorcinol and formaldehyde to condense in a resol-type condensation reaction in the presence of a base (Patent Document 2), and that the rosin acid on the surface of the latex undergoes addition condensation with the terminal methylol group of a resol-type phenol-formaldehyde addition condensate (Non-Patent Document 1).

[0011] During this aging, the latex crosslinks with the resol-type resorcinol-formaldehyde condensate via the rosin acid, strengthening the adhesion, and the latex forms an encapsulated protective colloid in combination with the aqueous resin. This suppresses the rubber-like tackiness of the latex when the adhesive composition is treated using the apparatus shown in Figure 1 or the like, thereby reducing staining of the apparatus due to the adhesive composition sticking to it, making this apparatus suitable for use.

[0012] As the adhesion promoter added to the RFL adhesive composition, an aqueous (water-dispersible or water-soluble) adhesion promoter has been used to improve adhesion of the aqueous adhesive composition to the surface of a substrate with low polarity, such as an organic fiber cord material.

[0013] Examples of the water-dispersible adhesion promoters that have been used include (blocked) isocyanates such as methylene diphenyl diisocyanate having a particle size of 0.01 to 0.50 μm (see Patent Document 3), and water-dispersed particles of water-insoluble phenolic novolac resins such as cresol novolac polyfunctional epoxy resins (see Patent Document 4).

[0014] Furthermore, examples of the adhesion promoter containing a water-soluble group that has been used in combination with an RFL adhesive composition include a sodium hydroxide solution of a novolac condensate obtained by a novolac reaction between resorcinol and formaldehyde (see Patent Document 5), and an ammonium solution of a novolac condensate of a chlorophenol and formaldehyde, as well as phenolic resins that dissolve in water in the presence of a basic substance, or aqueous urethane compounds having a (thermally dissociable blocked) isocyanate group and a group that is self-water-soluble (see Patent Document 6).

[0015] However, in recent years, there has been a demand to reduce the amount of resorcinol used as a water-soluble component in RFL adhesive compositions in order to reduce the environmental impact.

[0016] In order to address this issue, various adhesive compositions for organic fibers that do not contain resorcinol but use water as a solvent have been investigated and proposed.

[0017] For example, adhesive compositions for organic fibers that do not contain resorcinol include an adhesive composition comprising rubber latex, a blocked isocyanate compound, an epoxide compound, and an amino compound curing agent (see Patent Document 7), and an adhesive composition for organic fibers that contains a urethane resin having a (thermally dissociable blocked) isocyanate group, an epoxide compound, a polymer having an oxazoline group, a basic catalyst with a number-average molecular weight of 1,000 to 75,000, and rubber latex (see Patent Document 8). [Prior art documents] [Patent documents]

[0018] [Patent Document 1] U.S. Patent No. 2,128,229 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-263887 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-37251 [Patent Document 4] Japanese Patent Application Publication No. 9-12997 [Patent Document 5] International Publication No. 97 / 013818 [Patent Document 6] Japanese Patent Application Laid-Open No. 2011-241402 [Patent Document 7] International Publication No. 2010 / 125992 [Patent Document 8] Japanese Patent Application Laid-Open No. 2013-64037 [Non-patent literature]

[0019] [Non-Patent Document 1] Koichi Hakata, Network Polymer, Vol. 31, No. 5, p. 252, (2010) Summary of the Invention [Problem to be solved by the invention]

[0020] However, when using an adhesive composition for organic fibers that does not contain resorcinol as described above, the adhesive strength of the rubber latex, measured as the mechanical stability of the adhesive solution under shear strain, increases. As a result, for example, in the process of coating the organic fiber cord 1 shown in Figure 1 with the adhesive composition for organic fibers 2 and drying and heat curing it, the adhesive composition for organic fibers 2 adheres more to the squeeze roll 5 and the rolls in the drying zone 6, resulting in a new problem of poor workability in the process.

[0021] Furthermore, the adhesive composition for organic fibers that does not contain resorcinol as described above is - Since crosslinking between the latex component in the coating rubber composition and the resorcinol-formaldehyde condensate in the adhesive composition for organic fibers is not achieved in the first place, the adhesive properties are lower than those of conventional RFL adhesive compositions. The organic fibers tend to stick to the device used in the step of coating the organic fiber with the adhesive composition, which causes the surface coated with the adhesive to become rough, resulting in a decrease in adhesiveness. There was also the following issue.

[0022] Furthermore, the above-mentioned adhesive composition for organic fibers that does not contain resorcinol has the problem of reducing the cord strength of the organic fiber cord coated with the adhesive composition for organic fibers.

[0023] The present invention has been made in view of the above circumstances, (1) By not using resorcinol, the environmental impact is low. (2) By suppressing the tackiness of the rubber latex, which is measured as the mechanical stability under shear strain of the adhesive liquid, it is possible to suppress the adhesion of the adhesive composition for organic fibers to rolls, etc., in the process of coating organic fibers with the adhesive composition for organic fibers and drying and heat curing, thereby improving workability. (3) Good adhesion between the organic fiber and the coating rubber composition; The object of the present invention is to provide an adhesive composition for organic fibers that can achieve the above effects. Another object of the present invention is to provide an organic fiber-rubber composite using organic fibers coated with the adhesive composition for organic fibers, and a tire using the organic fiber-rubber composite. [Means for solving the problem]

[0024] In order to solve the above problems, the present inventors have conducted extensive research into the composition of adhesives for organic fibers, and as a result, have discovered that an adhesive composition for organic fibers comprising (A) a rubber latex having an unsaturated diene, (B) a polypeptide, and one or more of (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group, (D) an epoxide compound, and (E) a polyphenol, (1) By not using resorcinol, the environmental impact is low. (2) By suppressing the tackiness of the rubber latex, which is measured as the mechanical stability under shear strain of the adhesive liquid, it is possible to suppress the adhesion of the adhesive composition for organic fibers to rolls, etc., in the process of coating organic fibers with the adhesive composition for organic fibers and drying and heat curing, thereby improving workability. (3) Good adhesion between the organic fiber and the coating rubber composition; The present inventors have found that there is an adhesive composition for organic fibers that solves the above-mentioned problems, and have completed the present invention.

[0025] That is, the adhesive composition for organic fibers of the present invention comprises: (A) a rubber latex having an unsaturated diene; (B) a polypeptide, and The following (C)~(E): (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group; (D) epoxide compounds, (E) polyphenols, and one or more compounds selected from the group consisting of It is characterized by not containing resorcinol.

[0026] The organic fiber-rubber composite of the present invention is characterized by using organic fibers coated with the adhesive composition for organic fibers described above.

[0027] The organic fiber cord-rubber composite of the present invention is characterized by using an organic fiber cord coated with the adhesive composition for organic fibers described above.

[0028] The tire of the present invention is characterized by using the above organic fiber-rubber composite (or organic fiber cord-rubber composite). [Effects of the Invention]

[0029] According to the present invention, (1) By not using resorcinol, the environmental impact is low. (2) By suppressing the tackiness of the rubber latex, which is measured as the mechanical stability under shear strain of the adhesive liquid, it is possible to suppress the adhesion of the adhesive composition for organic fibers to rolls, etc., in the process of coating organic fibers with the adhesive composition for organic fibers and drying and heat curing, thereby improving workability. (3) Good adhesion between the organic fiber and the coating rubber composition; The adhesive composition for organic fibers that can achieve the above effects is provided. Also provided are an organic fiber-rubber composite using organic fibers coated with the adhesive composition for organic fibers, and a tire using the organic fiber-rubber composite. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic diagram showing an example of a process for coating an organic fiber cord with an adhesive composition for organic fibers by dipping. [Figure 2] FIG. 1 is a schematic diagram illustrating an example of the principle by which an adhesive composition for organic fibers of the present invention, in an embodiment, using a water-dispersible (thermally dissociable blocked) isocyanate compound (C-1), which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups, suppresses the tackiness of rubber latex and improves the adhesion between organic fibers and a coating rubber composition. [Figure 3](C-2) A schematic diagram illustrating an example of the principle by which the adhesive composition for organic fibers of the present invention, in an embodiment, suppresses the tackiness of rubber latex and improves the adhesion between organic fibers and a coating rubber composition when an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group is used. [Figure 4] 1 is a cross-sectional schematic view showing an example of an organic fiber-rubber composite of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] The adhesive composition for organic fibers, the organic fiber-rubber composite, and the tire of the present invention will be described in detail below based on their embodiments. These descriptions are for the purpose of illustrating the present invention and are not intended to limit the present invention in any way.

[0032] When a range is expressed herein, unless otherwise specified, the ends of the range are included within the range.

[0033] [Adhesive composition for organic fibers] The adhesive composition for organic fibers of the present invention comprises: (A) a rubber latex having an unsaturated diene; (B) a polypeptide, and The following (C)~(E): (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group; (D) epoxide compounds, (E) polyphenols, and one or more compounds selected from the group consisting of It is characterized by not containing resorcinol. The adhesive composition for organic fibers of the present invention is (1) By not using resorcinol, the environmental impact is low. (2) By suppressing the tackiness of the rubber latex, which is measured as the mechanical stability under shear strain of the adhesive liquid, it is possible to suppress the adhesion of the adhesive composition for organic fibers to rolls, etc., in the process of coating organic fibers with the adhesive composition for organic fibers and drying and heat curing, thereby improving workability. (3) Good adhesion between the organic fiber and the coating rubber composition; This has the effect of:

[0034] In the adhesive composition for organic fibers of the present invention, (A) the rubber latex having an unsaturated diene and (C) one or more compounds selected from the group consisting of an aqueous compound having a (thermally dissociable blocked) isocyanate group, (D) an epoxide compound, and (E) a polyphenol contribute to improving the adhesion between the organic fiber and the coating rubber composition. In addition, in the adhesive composition for organic fibers of the present invention, the polypeptide (B) contributes to improving workability. Furthermore, the adhesive composition for organic fibers of the present invention does not contain resorcinol, and therefore the environmental load can be reduced.

[0035] <Organic fibers (especially organic fiber cords)> The organic fibers (particularly organic fiber cords) of the organic fiber adhesive composition of the present invention are used to supplement the strength of rubber articles such as tires. When using the organic fiber cords as a reinforcing material, first, spun organic fiber raw yarns are twisted to form organic fiber cords. Then, the organic fibers (particularly organic fiber cords) are embedded in rubber coating the organic fibers (particularly organic fiber cords) using the organic fiber adhesive composition, and the resulting mixture is vulcanized and bonded to form an organic fiber-rubber composite (particularly organic fiber coat-rubber composite), which can be used as a reinforcing member for rubber articles such as tires.

[0036] The material of the organic fiber cord is not particularly limited, but examples of fiber materials that can be used include aliphatic polyamide fiber cords such as polyester, 6-nylon, 6,6-nylon, and 4,6-nylon, protein fiber cords such as artificial fibroin fiber, polyketone fiber cords, aromatic polyamide fiber cords such as polynonamethylene terephthalamide and paraphenylene terephthalamide, acrylic fiber cords, carbon fiber cords, and cellulose fiber cords such as rayon and lyocell. Of these, polyester, 6-nylon, and 6,6-nylon are preferred, with polyester being particularly preferred.

[0037] The polyester material is a polymer having ester bonds in the main chain, and more specifically, 80% or more of the bonding patterns of the repeating units in the main chain are ester bonding patterns. Examples of the polyester include, but are not limited to, those obtained by condensing glycols such as ethylene glycol, propylene glycol, butylene glycol, methoxypolyethylene glycol, and pentaerythritol with dicarboxylic acids such as terephthalic acid, isophthalic acid, and their dimethyl derivatives through an esterification reaction or an ester exchange reaction. The most representative polyester is polyethylene terephthalate.

[0038] The organic fiber cord is preferably an organic fiber cord formed by twisting together a plurality of monofilament filaments, particularly for the purpose of reinforcing rubber articles such as tires and conveyor belts. The organic fiber cord is also preferably an organic fiber cord formed by twisting together a top-twisted monofilament filament and a bottom-twisted monofilament filament. In this case, it is more preferable that the twist coefficient of the bottom twist be 1,300 or more and 2,500 or less, and / or the twist coefficient of the top twist be 900 or more and 1,800 or less.

[0039] <(A) Rubber Latex Having Unsaturated Diene> The "(A) latex having an unsaturated diene" in the adhesive composition for organic fibers of the present invention refers to a rubber latex containing an unsaturated diene that is vulcanizable with sulfur.

[0040] In one embodiment of the present invention, an example of the principle of action exhibited by the "(A) rubber latex having an unsaturated diene" contained in the adhesive composition for organic fibers will be described with reference to FIGS. 2 and 3. The rubber latex having an unsaturated diene 11 is a component for bonding an adhesive layer 32 of the adhesive composition for organic fibers 2 to a coating rubber composition 33 that is the adherend. The rubber latex having an unsaturated diene 11 is compatible with the rubber polymer contained in the coating rubber composition 33 that is the adherend, and further, the unsaturated diene moiety co-vulcanizes to form a rubber co-vulcanization bond 21. As a result, the adhesive composition for organic fibers of the present invention that contains the "(A) rubber latex having an unsaturated diene" provides good adhesion between the organic fibers and the coating rubber composition.

[0041] The (A) latex having an unsaturated diene is not limited, but examples thereof include "synthetic rubber latexes having an unsaturated diene" such as styrene-butadiene copolymer rubber latex, vinylpyridine-styrene-butadiene copolymer rubber latex, carboxyl group-modified styrene-butadiene copolymer rubber latex, nitrile rubber latex, and chloroprene rubber latex; and natural rubber latex such as field latex, ammonia-treated latex, and deproteinized latex. These may be used alone or in combination of two or more. Among these, vinylpyridine-styrene-butadiene copolymer rubber latex is preferred because it is a rubber latex that has been widely used in adhesive compositions for organic fibers and in articles such as tires, and because it also provides good bonding between the adhesive layer and the rubber substrate in the adhesive composition for organic fibers of the present invention, and because it is relatively soft and flexible, it allows the adhesive layer to deform without splitting.

[0042] The content (solids content) of the (A) unsaturated diene-containing rubber latex in the adhesive composition for organic fibers of the present invention is not particularly limited, but the lower limit is preferably 25% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more. The upper limit is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 65% ​​by mass or less. A content of 25% by mass or more ensures a more suitable compatibility between the rubber polymers of the rubber composition and the rubber latex contained in the adhesive composition for organic fibers, resulting in better adhesion of the coating rubber in the organic fiber-rubber composite. A content of 80% by mass or less ensures a certain relative amount of resin components contained as other components in the adhesive composition, resulting in sufficient cohesive fracture resistance of the adhesive layer and reduced fracture resistance within the adhesive layer, thereby achieving sufficient adhesion.

[0043] The synthetic rubber latex containing the unsaturated diene can be obtained, for example, by dissolving an emulsifier such as potassium rosinate in water, adding the monomer mixture, and then adding an electrolyte such as sodium phosphate and a peroxide as a polymerization initiator to carry out polymerization. After a predetermined conversion rate is reached, a charge transfer agent is added to terminate the polymerization, and the remaining monomer is removed. It is also preferable to use a chain transfer agent in the polymerization.

[0044] The emulsifier may be one or more of anionic surfactants such as alkali metal salts of fatty acids, alkali metal salts of rosin acid, formaldehyde-condensed sodium naphthalenesulfonate, sulfate esters of higher alcohols, alkylbenzenesulfonates, and aliphatic sulfonates, or nonionic surfactants such as alkyl esters, alkyl ethers, and alkylphenyl ethers of polyethylene glycol. Among these emulsifiers, it is preferable to include a metal salt of rosin acid, which can be used alone (only one type) or in combination with two or more other emulsifiers. In the production of the synthetic rubber latex containing an unsaturated diene in the examples of the present invention, an alkali metal salt of rosin acid was used alone as the emulsifier. Rosin acid is a mixture of resin acids with similar chemical structures, primarily consisting of tricyclic diterpenes obtained from pine resin, etc. These resin acids have a three-ring structure, two double bonds, and one carboxyl group, and the double bond portion has a highly reactive functional group that can esterify with the carboxyl group and the methylol end of unsaturated carboxylic acids or resol-type phenolic resins. The amount of such an emulsifier used is usually 0.1 to 8 parts by mass, and preferably 1 to 5 parts by mass, per 100 parts by mass of all the monomers used in the latex polymerization.

[0045] As the polymerization initiator, for example, a water-soluble initiator such as potassium persulfate, sodium persulfate, or ammonium persulfate, or a redox initiator, or an oil-soluble initiator such as benzoyl peroxide can be used. In the production of the synthetic rubber latex containing the unsaturated diene in the examples of the present invention, potassium persulfate was used as the polymerization initiator.

[0046] Examples of the chain transfer agent include monofunctional alkyl mercaptans such as n-hexyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan, and t-hexyl mercaptan; bifunctional mercaptans such as 1,10-decanedithiol and ethylene glycol dithioglycolate; trifunctional mercaptans such as 1,5,10-caneditrithiol and trimethylolpropane tristhioglycolate; tetrafunctional mercaptans such as pentaerythritol tetrakisthioglycolate; disulfides; halogen compounds such as carbon tetrachloride, carbon tetrabromide, and ethylene bromide; α-methylstyrene dimer, terpinolene, α-terpinene, dipentene, and allyl alcohol. These may be used alone or in combination of two or more. Of these chain transfer agents, alkyl mercaptans are preferred, and n-octyl mercaptan and t-dodecyl mercaptan are more preferred. In the production of the synthetic rubber latex containing the unsaturated diene in the examples of the present invention, t-dodecyl mercaptan was used as a chain transfer agent. The amount of such a chain transfer agent used is usually 0.01 to 5 parts by mass, preferably 0.1 to 3 parts by mass, per 100 parts by mass of all the monomers used in the latex polymerization.

[0047] In addition to the above, the latex may contain additives such as antioxidants such as hindered phenols, silicone-based, higher alcohol-based and mineral oil-based antifoaming agents, reaction terminators and antifreezing agents, if necessary.

[0048] <<Vinylpyridine-styrene-butadiene copolymer rubber latex>> The vinylpyridine-styrene-butadiene copolymer rubber latex is usually a terpolymer of a vinylpyridine-based monomer, a styrene-based monomer, and a conjugated diene-based butadiene monomer, but may further contain other monomers copolymerizable with these monomers.

[0049] Here, the vinylpyridine monomer includes vinylpyridine and substituted vinylpyridines in which hydrogen atoms in the vinylpyridine are substituted with substituents. Examples of the vinylpyridine compound include 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, and 5-ethyl-2-vinylpyridine. Among these, 2-vinylpyridine is preferred. These vinylpyridine monomers may be used alone or in combination of two or more.

[0050] The styrene-based monomer includes styrene and substituted styrenes in which hydrogen atoms in the styrene are substituted with substituents. Examples of the styrene-based monomer include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diynopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, and hydroxymethylstyrene. Among these, styrene is preferred. These styrene-based monomers may be used alone or in combination of two or more.

[0051] Examples of the conjugated diene-based butadiene monomer include aliphatic conjugated butadiene compounds such as 1,3-butadiene and 2-methyl-1,3-butadiene, and among these, 1,3-butadiene is preferred. These conjugated diene-based butadiene monomers may be used alone or in combination of two or more.

[0052] The vinylpyridine-styrene-butadiene copolymer rubber latex can be synthesized by a known method, specifically, the method described in JP-A-9-78045, which was studied by the inventors of the present application, can be used. By using these methods, it is possible to give the vinylpyridine-styrene-butadiene copolymer rubber latex various compositions and intra-particle structures, such as copolymers having uniform or different composition ratios within the same particle.

[0053] With regard to the vinylpyridine-styrene-butadiene copolymer rubber latex, examples of commercially available copolymers having a uniform monomer mixing ratio within the same particle include Nipol 2518 manufactured by Nippon Zeon Co., Ltd. and Piratex manufactured by Nippon A&L Co., Ltd. Furthermore, examples of commercially available copolymers having different monomer mixing ratios within the same particle include V0658 manufactured by JSR Corporation. All of these can be used as (A) the rubber latex having an unsaturated diene in the adhesive composition for organic fibers of the present invention.

[0054] The vinylpyridine-styrene-butadiene copolymer rubber latex is not particularly limited in terms of the vinylpyridine:styrene:butadiene monomer ratio. However, it is preferred that the copolymer constituting the vinylpyridine-styrene-butadiene copolymer particles contains a copolymer obtained by polymerizing a monomer mixture consisting of 5-20% by weight of vinylpyridine, 10-40% by weight of styrene, and 45-75% by weight of butadiene. A vinylpyridine content of 5% by weight or more provides an appropriate amount of pyridine moieties, which have a vulcanization-accelerating effect, in the rubber component. This increases the degree of crosslinking by sulfur, further improving the adhesive strength of the adhesive layer overall. A vinylpyridine content of 20% by weight or less prevents the rubber from becoming over-crosslinked, resulting in a hard adhesive. Furthermore, a styrene content of 10% by weight or more ensures sufficient strength of the latex particles and adhesive layer, further improving adhesive strength. A styrene content of 40% by weight or less ensures adequate co-vulcanization between the adhesive layer and the rubber substrate, while still ensuring sufficient adhesive strength. Furthermore, if the butadiene content is 45% by mass or more, more sufficient crosslinking can be formed, and if the butadiene content is 75% by mass or less, the crosslinking is moderate, and durability against changes in volume and modulus can be well ensured. In the synthetic rubber latex having an unsaturated diene in the examples of the present invention, the composition ratio of the monomer mixture of vinylpyridine:styrene:butadiene was set to 15:15:70.

[0055] <(B) Polypeptide> The "(B) polypeptide" in the adhesive composition for organic fibers of the present invention is a molecule in which amino acids are used as monomers and linked together in a chain (short chain) by peptide bonds. Examples of the polypeptide include polypeptides obtained by hydrolyzing proteins (derived from wool, milk, beans, silk, fish scales, or skin). It also includes derivatives in which the N-terminus of the polypeptide is converted to quaternary ammonium.

[0056] In one embodiment of the present invention, an example of the principle of action exhibited by the above-mentioned "(B) polypeptide" contained in the adhesive composition for organic fibers of the present invention will be described with reference to Figures 2 and 3. In conventional adhesive compositions for organic fibers containing resorcinol and formaldehyde, the resorcinol and formaldehyde form a resol-type resorcinol-formaldehyde condensate between rubber latex particles dispersed in an aqueous solvent, and also co-condense on the surface of the rubber latex in the adhesive composition for organic fibers by adding the methylol groups of the resorcinol-formaldehyde condensate to rosinate salts, etc., used as emulsifiers. This results in a coating of chemically crosslinked phenolic resins, which suppresses the tackiness of the rubber latex. On the other hand, in the adhesive composition for organic fibers of the present invention, polypeptide molecules of polypeptide 12 form a network in water at or below the gelation temperature, coating the surface of rubber latex 11 (core) having unsaturated diene. Rubber latex 11 having unsaturated diene is negatively (-) charged by rosin acid salts and carboxylic acids of unsaturated fatty acids emulsified on the surface, and cationic groups such as amino groups (-NH2) and (if present) thiol groups (-SH) of polypeptide 12 molecules are adsorbed to the network by electrostatic attraction to form a complex. This coating suppresses the adhesion of rubber latex 11 having unsaturated diene (latex-polypeptide protective film effect 20). As a result, the adhesive composition for organic fibers of the present invention containing "(B) polypeptide" suppresses the tackiness of rubber latex, which is measured as the mechanical stability of the adhesive liquid under shear strain. This makes it possible to suppress adhesion of the adhesive composition for organic fibers to rolls, etc., during the process of coating organic fibers with the adhesive composition for organic fibers and drying and heat curing, thereby improving workability. Furthermore, the polypeptide 12 of the adhesive composition 2 for organic fibers of the present invention coated on the surface of the organic fiber cord 1 is chemically crosslinked with the carboxylic acid portion of the highly reactive rosin acid by an amide bond or an ester bond upon heat treatment, thereby improving the adhesion between the organic fiber and the coating rubber composition.

[0057] Furthermore, when the adhesive composition for organic fibers of the present invention contains (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group, the amino group (-NH2), hydroxyl group (-OH), thiol group (-SH), etc. of the polypeptide 12 forms a polypeptide-isocyanate crosslink 22 with the activated isocyanate group 14 of the urethane resin 13 formed by the aqueous compound having a (thermally dissociable blocked) isocyanate group through high-temperature heat treatment after drying. As a result, an adhesive composition containing "(B) polypeptide" and "(C) an aqueous compound having a (thermally dissociable blocked) isocyanate group" exhibits better adhesion between organic fibers and coating rubber compositions.

[0058] In the organic fiber adhesive composition of the present invention, the (B) polypeptide is preferably a polypeptide obtained by hydrolyzing a protein. The polypeptide obtained by hydrolyzing a protein is not particularly limited, but examples thereof include protein hydrolysates obtained by hydrolyzing (or partially hydrolyzing) a protein with an acid or alkali. Protein sources for the protein hydrolysates include those derived from animals such as wool, milk, silk (silk fibroin), fish scales, and skins (pig skin, etc.), and those derived from plants such as beans (soybeans, almonds, etc.).

[0059] In the adhesive composition for organic fibers of the present invention, the polypeptide (B) is not particularly limited, but preferably has a number-average molecular weight of 100 to 20,000, more preferably 200 to 15,000, and even more preferably 300 to 8,000. The higher the number-average molecular weight, the greater the effect of improving adhesion, and the lower the number-average molecular weight, the better the stability in the adhesive composition. Within the above range, both adhesion and stability in the adhesive composition can be achieved. Furthermore, when the number-average molecular weight of the polypeptide is 300 to 8,000, the adhesion between the organic fiber and the coating rubber composition is improved.

[0060] As the polypeptide (B) in the adhesive composition for organic fibers of the present invention, commercially available polypeptides can be used. The polypeptides may be used singly or in combination of two or more.

[0061] In the adhesive composition for organic fibers of the present invention, the content (solids content) of the polypeptide (B) is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.3% by mass or more. It is also preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. A content of 0.1% by mass or more can further inhibit adhesion of the adhesive composition for organic fibers to rolls and the like, which has the advantage of improving workability. A content of 15% by mass or less prevents the amount of polypeptide contained in the adhesive layer from becoming too large, ensuring sufficient fracture resistance of the adhesive layer.

[0062] <(C), (D) and (E)> The adhesive composition for organic fibers of the present invention comprises (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group, (D) an epoxide compound, and (E) one or more compounds selected from the group consisting of a polyphenol. In the adhesive composition for organic fibers of the present invention, (C) the aqueous compound having a (thermally dissociable blocked) isocyanate group and (D) the epoxide compound function as crosslinking agents, contributing to improving the adhesion between the organic fibers and the coating rubber composition. On the other hand, (E) polyphenol has the function of improving the affinity between the adhesive composition and the surface of the organic fiber, and as a result, the adhesion between the organic fiber and the coating rubber composition can be improved. Therefore, (C) the aqueous compound having a (thermally dissociable blocked) isocyanate group, (D) the epoxide compound, and (E) the polyphenol all contribute to improving the adhesion between the organic fiber and the coating rubber composition.

[0063] <(C) Aqueous Compound Having a (Thermally Dissociable Blocked) Isocyanate Group> The "(thermally dissociable blocked) isocyanate group" in the "(C) aqueous compound having a (thermally dissociable blocked) isocyanate group" means a thermally dissociable blocked isocyanate group or an isocyanate group, (A) a thermally dissociable blocked isocyanate group formed by the reaction of an isocyanate group with a thermally dissociable blocking agent for the isocyanate group; (b) an isocyanate group which has not reacted with a thermally dissociable blocking agent for said isocyanate group; (c) an isocyanate group generated by dissociation of a thermally dissociable blocking agent from a thermally dissociable blocked isocyanate group; (d) an isocyanate group, Includes:

[0064] The term "aqueous" in the "(C) aqueous compound having a (thermally dissociable blocked) isocyanate group" refers to water-soluble or water-dispersible, and the term "water-soluble" does not necessarily mean complete water-solubility, but rather means partial water-solubility or no phase separation in the aqueous solution of the adhesive composition for organic fibers.

[0065] The "(C) aqueous compound having a (thermally dissociable blocked) isocyanate group" is preferably a water-dispersible (thermally dissociable blocked) isocyanate compound (C-1), which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups. In this case, the adhesion between the organic fiber and the coating rubber composition is improved. Here, with regard to the "(C-1) water-dispersible (thermally dissociable blocked) isocyanate compound, which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups," the "active hydrogen group" refers to a group containing hydrogen that becomes active hydrogen (atomic hydrogen (hydrogen radical) and hydride ion (hydride)) under suitable conditions. Examples of the active hydrogen group include an amino group and a hydroxyl group.

[0066] The thermally dissociable blocking agent is not particularly limited as long as it is a blocking agent compound that can protect the isocyanate groups from any chemical reaction while dissociating the blocking agent by heat treatment as necessary to restore the isocyanate groups. Specifically, the temperature of the heat treatment for thermal curing after the adhesive treatment liquid is applied and dried in the step shown in Figure 1 is preferably a thermal dissociation temperature at which the crosslinking reactivity of the isocyanate groups that have been blocked with the thermally dissociable blocking agent and whose reactivity has been suppressed can be restored. Examples of the blocking agent include, but are not limited to, alcohols, phenols, active methylenes, oximes, lactams, amines, and the like. Specific examples of the blocking agent include lactams such as ε-caprolactam, δ-valerolactam, and γ-butyrolactam; phenols such as phenol, cresol, ethylphenol, butylphenol, octylphenol, nonylphenol, dinonylphenol, thiophenol, chlorophenol, and amylphenol; oximes such as methyl ethyl ketoxime, acetoxime, acetophenone oxime, benzophenone oxime, and cyclohexanone oxime; alcohols such as methanol, ethanol, butanol, isopropyl alcohol, butyl alcohol, and cyclohexanol; malonic acid dialkyl esters such as dimethyl malonate and diethyl malonate; active methylenes such as methyl acetoacetate, ethyl acetoacetate, and acetylacetone; and mercaptans such as butyl mercaptan and dodecyl mercaptan. Examples of suitable amines include captans; amides such as acetanilide and acetic acid amide; imides such as succinimide, phthalimide, and maleimide; sulfites such as sodium bisulfite; cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; pyrazoles such as pyrazole, 3,5-dimethylpyrazole, 3-methylpyrazole, 4-benzyl-3,5-dimethylpyrazole, 4-nitro-3,5-dimethylpyrazole, 4-bromo-3,5-dimethylpyrazole, and 3-methyl-5-phenylpyrazole; amines such as dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, dicyclohexylamine, diphenylamine, xylidine, N,N-diethylhydroxyamine, N,N'-diphenylformamidine, 2-hydroxypyridine, 3-hydroxypyridine, and 2-mercaptopyridine; and triazoles such as 1,2,4-triazole. Mixtures of two or more of these may also be used. As these blocking agents, phenol, ε-caprolactam and ketoxime can be suitably used, which easily and stably achieve thermal curing of the adhesive composition by thermal dissociation upon heating.

[0067] Furthermore, the "(C-1) water-dispersible (thermally dissociable blocked) isocyanate compound which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups" specifically includes aromatic polyisocyanates or araliphatic polyisocyanates, and examples of aromatic isocyanates include phenylene diisocyanates such as m-phenylene diisocyanate and p-phenylene diisocyanate; tolylene diisocyanates such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate (TDI); 2,4'-diphenylmethane diisocyanate; diphenylmethane diisocyanates such as 4,4'-diphenylmethane diisocyanate (MDI), dialkyldiphenylmethane diisocyanate, and tetraalkyldiphenylmethane diisocyanate; polymethylene polyphenyl polyisocyanate (polymeric MDI); m- or p-isocyanatophenylsulfonyl isocyanates; diisocyanatobiphenyls such as 4,4'-diisocyanatobiphenyl and 3,3'-dimethyl-4,4'-diisocyanatobiphenyl; and naphthalene diisocyanates such as 1,5-naphthylene diisocyanate. Examples of aromatic aliphatic polyisocyanates include xylylene diisocyanates such as m-xylylene diisocyanate, p-xylylene diisocyanate (XDI), and tetramethylxylylene diisocyanate; diethylbenzene diisocyanate; and α,α,α,α-tetramethylxylylene diisocyanate (TMXDI). Further examples include modified products of the above polyisocyanates, such as carbodiimide, polyol, and allophanate. Of these polyisocyanates containing an aromatic ring in the molecule, from the viewpoint of the cord bundling properties of the adhesive composition, aromatic isocyanates are preferred, more preferred are tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI) or polymethylene polyphenyl polyisocyanate (polymeric MDI), and particularly preferred is diphenylmethane diisocyanate (MDI). The water-dispersible (thermally dissociable blocked) isocyanate compound (C-1), which is an addition product of an aromatic ring-containing polyisocyanate and a blocking agent having one or more active hydrogen groups, is preferably a blocked product of methylene diphenyl diisocyanate (also called "diphenylmethane diisocyanate"), which improves the adhesion between the organic fiber and the coating rubber composition.

[0068] Furthermore, the "(C) aqueous compound having a (thermally dissociable blocked) isocyanate group" is more preferably (C-2) an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group, which also improves the adhesion between the organic fiber and the coating rubber composition. The (C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group will be described in detail below.

[0069] The content (solids content) of the aqueous compound (C) having a (thermally dissociable blocked) isocyanate group is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. It is also preferably 75% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. A content of 5% by mass or more improves the adhesion between the organic fiber and the coating rubber composition. A content of 75% by mass or less ensures that the amount of other components, such as rubber latex, blended into the adhesive composition for organic fibers is at a certain level, resulting in better adhesion to the rubber coating.

[0070] In conventional adhesive compositions for organic fibers containing resorcinol and formaldehyde, a sea-island structure is formed in which rubber latex particles (likely islands) are dispersed in a phenolic resin (likely the sea) formed by co-condensation of the resorcinol and formaldehyde, thereby achieving good adhesion between the phenolic resin that coats the surface of the organic fiber and the organic fiber.

[0071] On the other hand, in a preferred embodiment of the adhesive composition for organic fibers of the present invention, the "(C) aqueous compound having a (thermally dissociable blocked) isocyanate group" functions as an adhesion promoter in place of the phenolic resin obtained by co-condensation of resorcinol and formaldehyde, and has the following two functional effects: (a) The functional effect of distributing the aqueous compound near the interface between the organic fiber and the adhesive layer of the adhesive composition for organic fiber, thereby promoting adhesion between the organic fiber and the adhesive layer. (b) Within the adhesive layer of the organic fiber adhesive composition, a three-dimensional network structure is formed by crosslinking through the isocyanate groups of the compound having the (thermally dissociable blocked) isocyanate group, thereby providing a functional effect of reinforcing the adhesive layer. As a result, in the adhesive composition for organic fibers, the “(C) aqueous compound having a (thermally dissociable blocked) isocyanate group” contributes to the characteristic of good adhesion between the organic fibers and the coating rubber composition.

[0072] In one embodiment of the adhesive composition for organic fibers of the present invention, an example of the principles of (a) and (b), which are the functional effects of the “(C) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group” as the two adhesion promoters, is as follows: In the case where the "(C) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" is a water-dispersible (thermally dissociable blocked) isocyanate compound that is an addition product of (C-1) a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups, the following is described with reference to FIG. 2: In the case where the "(C) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" is an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group (C-2), the following is performed with reference to FIG. 3: A detailed explanation will be given below.

[0073] <<(a) Functional effect as an adhesion promoter>> Polyester synthetic resin materials such as polyethylene terephthalate, which are widely used as organic fibers, are composed of flat, linear polymer chains. The surfaces of the polymer chains or the gaps between the polymer chains have a π-electron atmosphere derived from aromatics contained in the polymer chains. Furthermore, polyester has particularly fewer hydroxyl groups on its surface than 6,6-nylon. Therefore, adhesive compositions for organic fibers used for polyester organic fibers have been conventionally formulated to obtain sufficient adhesive strength by: The adhesive composition for organic fibers is dispersed into the gaps between the polymer chains of the organic fibers, and The adhesive layer of the adhesive composition for organic fibers adheres closely to the surface of the polymer chains of the organic fibers. To this end, molecules with a planar structure having aromatic rings with aromatic π electrons on the sides ("portions that easily diffuse into organic fibers") have been included as adhesion promoters. As a specific example of such an adhesion promoter, the above-mentioned "(C-1) water-dispersible (thermally dissociable blocked) isocyanate compound which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups" has been used.

[0074] The "(C-1) water-dispersible (thermally dissociable blocked) isocyanate compound which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups" is preferably a (blocked) isocyanate such as methylene diphenyl diisocyanate having a particle size of 0.01 to 0.50 μm (see Patent Document 3). In the adhesive layer containing the "(C-1) water-dispersible (thermally dissociable blocked) isocyanate compound which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups," as shown in FIG. 2, in the adhesive layer 32 made of the adhesive composition for organic fibers 2, the (C-1) water-dispersible (thermally dissociable blocked) isocyanate compound which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups diffuses into the organic fiber cord 1 (aromatic isocyanate-organic fiber diffusion effect 41) and forms a polypeptide-isocyanate crosslink 22 by a covalent bond with a polypeptide 12 contained in the adhesive layer, thereby The adhesive composition for organic fibers 2 is dispersed into the gaps between the polymer chains of the organic fiber cord 1, and The adhesive layer 32 of the organic fiber adhesive composition 2 adheres closely to the surface of the polymer chain of the organic fiber cord 1. This becomes:

[0075] As mentioned above, the "water-dispersible (thermally dissociable blocked) isocyanate compound (C-1), which is an addition product of an aromatic ring-containing polyisocyanate and a blocking agent having one or more active hydrogen groups," preferably has a particle size of 0.01 to 0.50 μm. However, if the particle size is less than 0.01 μm, the compound will tend to diffuse over time from the surface of the organic fiber polymer chains in the adhesive layer to the gaps between the organic fiber polymer chains, where aromatic π electrons are more abundant, thereby reducing its effectiveness as an adhesion promoter. Therefore, a certain particle size is required to remain on the surface of the organic fiber. Furthermore, if the particle size is 0.50 μm or less, the compound is less likely to settle in the liquid and less likely to be dispersed unevenly in the adhesive layer.

[0076] It is further preferable that the adhesive composition for organic fibers contains "(C-2) an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" that has, in its molecular structure, not only a hydrophobic aromatic polyisocyanate portion that is "a portion that easily diffuses into organic fibers" but also a hydrophilic molecular chain portion that is "a portion that is difficult to diffuse into organic fibers."

[0077] As shown in Figure 3, in the adhesive layer 32 made of the organic fiber adhesive composition 2, the urethane resin 13 formed by the aqueous urethane compound having a (thermally dissociable blocked) isocyanate group has both a portion 15 that easily interacts with the organic fiber cord 1 and a portion 16 that is difficult to diffuse into the organic fiber cord 1. Among these, the adhesive layer 32 of the organic fiber adhesive composition 2 adheres closely to the surface of the polymer chain of the organic fiber cord 1 due to the presence of the portion 15 that is likely to interact with the organic fiber cord. Furthermore, due to the presence of the portions 16 that are difficult to diffuse in the organic fiber cord 1, the urethane resin 13 formed from the aqueous urethane compound having a (thermally dissociable blocked) isocyanate group maintains its functional effect of promoting adhesion at the interface with the adhesive layer 32 (aqueous urethane-organic fiber interface effect 24). As a result, an adhesive composition for organic fibers containing "(C-2) an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" exhibits good adhesion between organic fibers and a coating rubber composition.

[0078] In addition, if the aqueous compound having (C) a (thermally dissociable blocked) isocyanate group is an aromatic polyisocyanate compound having an anionic or nonionic water-soluble functional group, it tends to disperse in water from the surface of the hydrophobic organic fiber cord 1, and therefore it is more preferable that the aqueous compound be (C-2) a (thermally dissociable blocked) isocyanate group.

[0079] <<(b) Functional effect as an adhesion promoter>> In addition, in an adhesive layer containing (C-1) a water-dispersible (thermally dissociable blocked) isocyanate compound, which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups, as shown in Figure 2, the activated isocyanate group formed by thermal dissociation of the blocking agent in the water-dispersible (thermally dissociable blocked) isocyanate compound 40, which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups, forms a polypeptide-isocyanate crosslink 22 with the molecular chain of the adjacent polypeptide 12, resulting in an adhesive layer having a three-dimensional network structure. As a result, an adhesive composition for organic fibers containing "(C-1) a water-dispersible (thermally dissociable blocked) isocyanate compound which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups" exhibits good adhesion between the organic fibers and the coating rubber composition.

[0080] Since the material used is one in which aromatic-based powder is forcibly emulsified and dispersed, it is preferable to agitate the dipping bath 3 in Figure 1 to prevent the compounds from settling in the liquid and becoming unevenly dispersed in the adhesive layer, resulting in aggregation.

[0081] On the other hand, the adhesive composition for organic fibers of the present invention more preferably contains the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" as an adhesion promoter. The "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" contains an alkylene oxide moiety or the like in the molecule, and therefore can be uniformly dispersed in water by self-emulsification due to swelling in water.

[0082] Furthermore, since the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" uniformly dispersed in water contains a hydrophobic organic isocyanate moiety within the compound molecule, the hydrophobic moieties of adjacent water-soluble urethanes form stable association micelles, similar to the water-soluble urethanes used in, for example, associative thickeners, and a three-dimensional network structure is formed due to hydrophobic interactions between the aqueous urethanes uniformly dispersed in the liquid.

[0083] Next, the organic fiber adhesive composition having a three-dimensional network structure formed by hydrophobic bonds is coated onto an organic fiber cord, followed by drying and thermal curing. As a result, as shown in Figure 3, adjacent activated isocyanate groups 14 formed by thermal dissociation of the blocking agent form activated isocyanate crosslinks 23 via covalent bonds, resulting in an adhesive layer containing a three-dimensional network structure of urethane resin 13 formed by the aqueous urethane compound having a (thermally dissociable, blocked) isocyanate group. As a result, the organic fiber adhesive composition containing "(C-2) an aqueous urethane compound having a (thermally dissociable, blocked) isocyanate group" provides good adhesion between the organic fiber and the coating rubber composition.

[0084] <<Thermal dissociation blocking agent, water-based urethane compound>> The thermally dissociable blocking agent for the (C-2) aqueous compound having a (thermally dissociable blocked) isocyanate group is not particularly limited as long as it is a blocking agent compound that can protect the isocyanate group from any chemical reaction while dissociating the blocking agent by heat treatment as necessary to restore the isocyanate group. Specific examples of the thermally dissociable blocking agent include the same compounds as those described above for the (C-1) water-dispersible (thermally dissociable blocked) isocyanate compound, which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups. Preferred examples include phenols such as phenol, thiophenol, chlorophenol, cresol, resorcinol, p-sec-butylphenol, p-tert-butylphenol, p-sec-amylphenol, p-octylphenol, and p-nonylphenol; secondary or tertiary alcohols such as isopropyl alcohol and tert-butyl alcohol; Examples of the compound include aromatic secondary amines such as diphenylamine and xylidine; phthalimides; lactams such as δ-valerolactam; caprolactams such as ε-caprolactam; dialkyl malonate esters such as diethyl malonate and dimethyl malonate, active methylene compounds such as acetylacetone and alkyl acetoacetate esters; oximes such as acetoxime, methyl ethyl ketoxime, and cyclohexanone oxime; basic nitrogen compounds such as 3-hydroxypyridine, 1,2-pyrazole, 3,5-dimethylpyrazole, 1,2,4-triazole, diisopropylamine, and N,N'-diphenylformamidine; and acidic sodium sulfite. As these blocking agents, phenol, ε-caprolactam and ketoxime can be suitably used, which easily and stably achieve thermal curing of the adhesive composition by thermal dissociation upon heating.

[0085] The term "aqueous" in the "aqueous urethane compound" refers to water-soluble or water-dispersible compounds, and the term "water-soluble" does not necessarily mean complete water-solubility, but rather means partial water-solubility or no phase separation in the aqueous solution of the organic fiber adhesive composition.

[0086] The "urethane compound" in the "aqueous urethane compound" is a compound having a covalent bond formed between the nitrogen of an amine and the carbon of a carbonyl group, and refers to a compound represented by the following general formula (2). [ka] In the above formula (2), R and R' represent hydrocarbon groups.

[0087] The molecular weight of the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" is not particularly limited as long as it maintains its aqueous nature, but the number average molecular weight is preferably 1,500 to 100,000, and particularly preferably 9,000 or less.

[0088] As described above, the method for synthesizing the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" is not particularly limited, but may be a known method such as the method described in JP-A-63-51474.

[0089] <<Preferred Embodiments of "(C-2) Aqueous Urethane Compound Having a (Thermally Dissociable Blocked) Isocyanate Group">> A preferred embodiment of the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" is (α) an organic polyisocyanate compound having 3 or more and 5 or less functional groups and a number average molecular weight of 2,000 or less; (β) a compound having 2 or more and 4 or less active hydrogen groups and a number average molecular weight of 5,000 or less; (γ) a thermally dissociable blocking agent, and (δ) a compound having at least one active hydrogen group and at least one anionic, cationic, or nonionic hydrophilic group; The mixing ratio of each of (α), (β), (γ) and (δ) to the total amount is (α) is 40 mass% or more and 85 mass% or less, (β) is 5% by mass or more and 35% by mass or less, (γ) is 5 mass% or more and 35 mass% or less, and (δ) is 5% by mass or more and 35% by mass or less, The reaction product after mixing and reacting is The composition ratio of the (thermally dissociable blocked) isocyanate group in the reaction product is 0.5% by mass or more and 11% by mass or less, when the molecular weight of the isocyanate group (-NCO) is 42. In this case, the adhesion between the organic fiber and the coating rubber composition is improved. This is because the above-mentioned "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" has both a moiety consisting of a (thermally dissociable blocked) isocyanate group and a hydrophilic moiety having a hydrophilic group, and therefore has the advantage of increasing the self-water solubility of the urethane compound.

[0090] The (α) organic polyisocyanate compound having 3 to 5 functional groups and a number-average molecular weight of 2,000 or less is not particularly limited, but is preferably an aromatic polyisocyanate compound and its oligomer, or may be other aliphatic, alicyclic, or heterocyclic polyisocyanate compound and its oligomer. This is because the reaction product obtained by reacting such (α) organic polyisocyanate compound having 3 to 5 functional groups and a number-average molecular weight of 2,000 or less, "(C-2) aqueous urethane compound having (thermally dissociable blocked) isocyanate groups," is more likely to disperse into the gaps between the polymer chains of organic fibers. Specific examples of aliphatic polyisocyanate compounds include ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate, and lysine diisocyanate. Specific examples of alicyclic polyisocyanate compounds include cyclobutane diisocyanate, cyclobutane diisocyanate, and cyclohexane diisocyanate. Heterocyclic polyisocyanate compounds include 1,3,5-tris(2'-hydroxybenzoate), 1,3-diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, isophorone diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate, and 1,3-(isocyanatomethyl)cyclohexane. Examples of aromatic polyisocyanate compounds include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, m-tetramethylxylylene diisocyanate, p-tetramethylxylylene diisocyanate, methine tris(4-phenylisocyanate), tris(4-isocyanatophenyl)methane, thiophosphate tris(4-isocyanatophenyl ester), 3-isopropenyl-α',α'-dimethylbenzyl isocyanate, and oligomer mixtures thereof; and modified products of these polyisocyanate compounds such as carbodiimide, polyol, and allophanate. Among these, aromatic polyisocyanate compounds are preferred, and methylene diphenyl polyisocyanate, polyphenylene polymethylene polyisocyanate, etc. are particularly preferred. Polyphenylene polymethylene polyisocyanate with a number average molecular weight of 2,000 or less is preferred, and polyphenylene polymethylene polyisocyanate with a number average molecular weight of 1,000 or less is particularly preferred. This is because the reaction product obtained by reacting such (α) organic polyisocyanate compounds having 3 to 5 functional groups and a number average molecular weight of 2,000 or less, "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group," is more easily dispersed into the gaps between polymer chains of organic fibers.

[0091] The (β) compound having 2 or more and 4 or less active hydrogen groups and a number average molecular weight of 5,000 or less is not particularly limited, but specific examples thereof include compounds selected from the group consisting of the following (i) to (vii): (i) Polyhydric alcohols having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less; (ii) polyamines having 2 to 4 primary and / or secondary amino groups and a number average molecular weight of 5,000 or less; (iii) amino alcohols having two to four primary and / or secondary amino groups and a hydroxyl group and a number average molecular weight of 5,000 or less; (iv) polyester polyols having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less; (v) Polybutadiene polyols and copolymers thereof with other vinyl monomers, having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less; (vi) Polychloroprene polyols and copolymers thereof with other vinyl monomers, having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less; (vii) Polyether polyols having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less; polyamines, C2-C4 alkylene oxide polyaddition products of polyhydric phenols and amino alcohols, C2-C4 alkylene oxide polyaddition products of C3 or higher polyhydric alcohols, C2-C4 alkylene oxide copolymer, or C3-C4 alkylene oxide polymer.

[0092] Here, in the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group," the "active hydrogen group" refers to a group containing hydrogen that becomes active hydrogen (atomic hydrogen (hydrogen radical) and hydride ion (hydride)) under suitable conditions. Examples of the active hydrogen group include an amino group and a hydroxyl group.

[0093] The compound having at least one active hydrogen group and at least one anionic hydrophilic group in the "(δ) compound having at least one active hydrogen group and at least one anionic, cationic, or nonionic hydrophilic group" is not particularly limited, but examples thereof include taurine, N-methyltaurine, N-butyltaurine, aminosulfonic acids such as sulfanilic acid, and aminocarboxylic acids such as glycine and alanine.

[0094] The method for synthesizing the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" by mixing and reacting the (α), (β), (γ), and (δ) is not particularly limited, but may be a known method such as the method described in JP-A-63-51474.

[0095] <<Another Preferred Embodiment of “(C-2) Aqueous Urethane Compound Having a (Thermally Dissociable Blocked) Isocyanate Group”>> Another preferred embodiment of the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" is (α) an organic polyisocyanate compound having 3 or more and 5 or less functional groups and a number average molecular weight of 2,000 or less; (β) a compound having 2 or more and 4 or less active hydrogen groups and a number average molecular weight of 5,000 or less; (γ) a thermally dissociable blocking agent, and (δ) a compound having at least one active hydrogen group and at least one anionic, cationic, or nonionic hydrophilic group; (ε) Compounds containing active hydrogen groups other than (α), (β), (γ), and (δ) The mixing ratio of each of (α), (β), (γ), (δ) and (ε) to the total amount is (α) is 40 mass% or more and less than 85 mass%; (β) is 5% by mass or more and 35% by mass or less, (γ) is 5 mass% or more and 35 mass% or less, (δ) is 5% by mass or more and 35% by mass or less, (ε) is greater than 0 mass% and less than 45 mass% The reaction product after mixing and reacting is Furthermore, when the molecular weight of the isocyanate group (-NCO) is 42, the composition ratio of the (thermally dissociable blocked) isocyanate group in the reaction product is 0.5 mass % or more and 11 mass % or less. This is because the above-mentioned (C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group has both a moiety consisting of a (thermally dissociable blocked) isocyanate group and a hydrophilic moiety having a hydrophilic group, and therefore has the advantage of increasing the self-water solubility of the urethane compound.

[0096] Here, (α) the organic polyisocyanate compound having 3 to 5 functional groups and a number-average molecular weight of 2,000 or less, (β) the compound having 2 to 4 active hydrogen groups and a number-average molecular weight of 5,000 or less, (γ) the thermally dissociable blocking agent, and (δ) the compound having at least one active hydrogen group and at least one anionic, cationic, or nonionic hydrophilic group are as described in the above-mentioned <<Preferred embodiment of “(C-2) Aqueous urethane compound having a (thermally dissociable blocked) isocyanate group”>>, except for the mixing ratio.

[0097] The method for synthesizing the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" by mixing and reacting the (α), (β), (γ), (δ), and (ε) is not particularly limited, but may be a known method such as the method described in JP-A-63-51474.

[0098] <<Further Preferred Embodiment of “(C-2) Aqueous Urethane Compound Having a (Thermally Dissociable Blocked) Isocyanate Group”>> Another preferred embodiment of the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" is a compound represented by the following general formula (1): [ka] [In formula (1), A is a residue of an organic polyisocyanate compound from which an active hydrogen group has been eliminated, X is a residue of a polyol compound having 2 or more and 4 or less hydroxyl groups and a number average molecular weight of 5,000 or less, from which an active hydrogen group has been eliminated; Y is a residue of the thermally dissociable blocking agent from which the active hydrogen group has been eliminated, Z is a residue of a compound having at least one active hydrogen group and at least one salt-forming group or hydrophilic polyether chain, from which the active hydrogen group has been eliminated; n is an integer between 2 and 4, p+m is an integer between 2 and 4 (m≧0.25), In this case, the adhesion between the organic fiber and the coating rubber composition is improved. The above-mentioned "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" has both a moiety consisting of a (thermally dissociable blocked) isocyanate group and a hydrophilic moiety having a hydrophilic group, and therefore has the advantage of increasing the self-water solubility of the urethane compound.

[0099] Here, it is preferable that the "organic polyisocyanate compound" of the "residue of an organic polyisocyanate compound from which an active hydrogen group has been eliminated," which is A in formula (1), contains an aromatic ring, because this allows the "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" to be more easily dispersed into the gaps between the polymer chains of the organic fiber. Although not particularly limited, examples include methylene diphenyl polyisocyanate, polyphenylene polymethylene polyisocyanate, etc. Polyphenylene polymethylene polyisocyanate having a number average molecular weight of 6,000 or less is preferred, and polyphenylene polymethylene polyisocyanate having a number average molecular weight of 4,000 or less is particularly preferred.

[0100] The "polyol compound having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less" of the "residue resulting from the elimination of an active hydrogen group from a polyol compound having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less" represented by X in formula (1) is not particularly limited, and specific examples thereof include compounds selected from the group consisting of the following (i) to (vi): (i) Polyhydric alcohols having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less; (ii) amino alcohols having two to four primary and / or secondary amino groups and a hydroxyl group and a number average molecular weight of 5,000 or less; (iii) polyester polyols having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less; (iv) Polybutadiene polyols and copolymers thereof with other vinyl monomers, each having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less; (v) Polychloroprene polyols and copolymers thereof with other vinyl monomers, having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less; (vi) Polyether polyols having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less. polyamines, C2-C4 alkylene oxide polyaddition products of polyhydric phenols and amino alcohols, C2-C4 alkylene oxide polyaddition products of C3 or higher polyhydric alcohols, C2-C4 alkylene oxide copolymer, or C3-C4 alkylene oxide polymer.

[0101] The "(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group" is not particularly limited, but commercially available products such as Elastron BN27, BN77, and BN11 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. may also be used. Preferably, BN77 was used in the following examples of this specification.

[0102] <(D) Epoxide Compound> One embodiment of the adhesive composition for organic fibers of the present invention comprises (A) a rubber latex having an unsaturated diene, (B) a polypeptide, and (D) an epoxide compound. The adhesive composition does not contain resorcinol.

[0103] The "(D) epoxide compound" refers to a compound having an oxacyclopropane (oxirane) (epoxy group), which is a three-membered ring ether, in its structural formula.

[0104] The "(D) epoxide compound" functions as a crosslinking agent component in the adhesive composition for organic fibers. That is, when the adhesive composition contains the "(D) epoxide compound," crosslinks are introduced between the hydroxyl groups, amine groups, and thiol groups contained in the amino acid units of the "(B) polypeptide," resulting in improved fracture resistance of the adhesive layer and significant improvements in adhesive strength at high temperatures.

[0105] Furthermore, it is preferable to heat the "(D) epoxide compound" mixed with the "(C) aqueous compound having a (thermally dissociable blocked) isocyanate group." When such a "(D) epoxide compound" and the "(C) aqueous compound having a (thermally dissociable blocked) isocyanate group" are mixed and heated, crosslinking occurs in the adhesive composition for organic fibers, which is mainly composed of urethane bonds, due to a nucleophilic reaction between the epoxy group of the "(D) epoxide compound" and the amine, alcohol, thiol, phenol, carboxylic acid, or isocyanate (from which the thermally dissociable block has dissociated) contained in the (C) aqueous compound having a (thermally dissociable blocked) isocyanate group, thereby suppressing creep and flow due to stress at high temperatures. Furthermore, it is preferable that the epoxy group of the "(D) epoxide compound" is polyfunctional, because this enhances the suppression effect, further increases the fracture resistance of the adhesive layer formed by the adhesive composition for organic fibers, and further increases the adhesive strength at high temperatures.

[0106] The "(D) epoxide compound" is preferably a compound containing two or more epoxy groups in one molecule. It is particularly preferably a compound containing four or more epoxy groups in one molecule. The reason for this is that the epoxy groups become multifunctional, and as described above, the fracture resistance of the adhesive layer formed by the adhesive composition for organic fibers is further increased, and the adhesive strength at high temperatures is also further increased. Furthermore, when the (D) epoxide compound has two or more epoxy groups in one molecule, creep and flow due to stress in the high temperature range are further suppressed in an adhesive composition for organic fibers containing such an epoxide compound (D), and the adhesive strength at high temperatures is further increased.

[0107] Specific examples of the "(D) epoxide compound" include reaction products of epichlorohydrin with polyhydric alcohols such as diethylene glycol diglycidyl ether, polyethylene diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, and sorbitol polyglycidyl ether; novolac epoxy resins such as phenol novolac epoxy resins and cresol novolac epoxy resins; and bisphenol A epoxy resins. Reaction products of polyhydric alcohols and epichlorohydrin or novolac epoxy resins are preferred, and reaction products of polyhydric alcohols and epichlorohydrin are more preferred. The (D) epoxide compound, which is a reaction product of a polyhydric alcohol and epichlorohydrin, can be used by dissolving it in water or dispersing it in water by emulsification, and therefore, an adhesive composition for organic fibers containing such a (D) epoxide compound can be produced more easily. The sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, and novolac epoxy resin may be commercially available chemicals.

[0108] The "(D) epoxide compound" can be used by dissolving it in water or dispersing it in water by emulsification. For example, the "(D) epoxide compound" can be dissolved in water as is. Alternatively, the "(D) epoxide compound" can be dissolved in a small amount of solvent as needed, and the resulting solution can be emulsified in water using a known emulsifier (e.g., sodium alkylbenzenesulfonate, dioctyl sulfosuccinate sodium salt, nonylphenol ethylene oxide adduct, etc.) to prepare an emulsion.

[0109] The content (solids content) of the "(D) epoxide compound" is not particularly limited, but is preferably 1% by mass or more, and more preferably 5% by mass or more. It is also preferably 45% by mass or less, and more preferably 40% by mass or less. A content of 1% by mass or more improves the adhesion between the resin and the coating rubber composition. A content of 40% by mass or less makes it possible to ensure a certain relative amount of other components, such as rubber latex, blended into the adhesive composition, resulting in better adhesion to the rubber coating.

[0110] <(E) Polyphenols> One embodiment of the adhesive composition for organic fibers of the present invention comprises (A) a rubber latex having an unsaturated diene, (B) a polypeptide, and (E) a polyphenol. The adhesive composition does not contain resorcinol, and preferably does not contain formaldehyde.

[0111] The "(E) polyphenol" is preferably a plant-derived compound having multiple phenolic hydroxy groups in the molecule, which improves the adhesion between the organic fiber and the coating rubber composition.

[0112] Research has long been conducted into the production of adhesives by separating polyphenols such as lignin and tannin, which are components of wood and bark, and reacting them with formaldehyde (for example, JP-A-07-53858), but there is little knowledge about producing aqueous adhesive compositions that do not contain resorcinol.

[0113] Furthermore, the (E) polyphenol is preferably lignin or a derivative thereof. In this case, the adhesion between the organic fiber and the coating rubber composition is also improved. Particularly preferred examples of the lignin or its derivative include calcium lignin sulfonate, sodium lignin sulfonate, potassium lignin sulfonate, and magnesium lignin sulfonate, which are derived from the eluate of sulfite pulp or the like. Among these, sodium lignin sulfonate is preferred.

[0114] The content (solids content) of the "(E) polyphenol" is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more. It is also preferably 75% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. A content of 5% by mass or more improves the adhesion between the organic fiber and the coating rubber composition. A content of 75% by mass or less ensures that the amount of other components, such as rubber latex, blended into the adhesive composition for organic fibers is at least a certain level, resulting in better adhesion to the rubber coating.

[0115] <Method of manufacturing adhesive composition for organic fibers> The adhesive composition for organic fibers of the present invention comprises: (A) a rubber latex having an unsaturated diene; (B) a polypeptide, and The following (C)~(D): (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group; (D) epoxide compounds, (E) polyphenols, In producing the adhesive composition for organic fibers, (A) a rubber latex having an unsaturated diene, (B) a polypeptide, (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group, (D) an epoxide compound, and (E) a polyphenol can be mixed in any order.

[0116] However, when the "(D) epoxide compound" is mixed with water, the epoxy groups tend to react with water, gradually deactivating its function as a crosslinking agent. Therefore, after mixing the "(D) epoxide compound" with water, it is preferable to subject the adhesive composition for organic fibers to a coating treatment for organic fibers as soon as possible. Specifically, after mixing the "(D) epoxide compound" with water, it is preferable to subject the adhesive composition for organic fibers to a coating treatment for organic fibers within two days, and more preferably within one day.

[0117] In the adhesive composition for organic fibers of the present invention, the mixing mass ratio [(A):(B)] (solid content equivalent) of the "(A) rubber latex having an unsaturated diene" to the "(B) polypeptide" is not particularly limited, but is preferably in the range of 100:0.1 to 100:25, and more preferably in the range of 100:0.2 to 100:5 (both of the mixing mass ratios). When the mixing mass ratio is 100:0.1 or more (when the ratio value is 1000 or less), a microcapsule membrane of "(B) polypeptide" can be formed around "(A) rubber latex having unsaturated diene" as a core, and an adhesive layer of sufficient strength can also be obtained. Furthermore, if the mixing mass ratio is 100:25 or less (if the ratio value is 4 or more), the microcapsule coating of "(B) polypeptide" formed around the "(A) rubber latex having an unsaturated diene" as a core will not become too thick, and when the coated rubber composition as an adherend of the organic fiber and the adhesive composition for organic fiber are co-vulcanized to bond them, the coated rubber composition as an adherend and the "(A) rubber latex having an unsaturated diene" will be well miscible, and as a result, the initial process of adhesion between the coated rubber composition as an adherend and the adhesive composition for organic fiber will proceed smoothly.

[0118] When mixing the "(A) rubber latex having an unsaturated diene" with the "(B) polypeptide," a known water-soluble material capable of strengthening the film of the "(B) polypeptide" by a conventional coacervate can be used in combination. For example, gum arabic, carrageenan, CMCs, and electrolyte substances consisting of organic or inorganic salts, such as salts having cations such as sodium chloride, potassium chloride, magnesium chloride, and ammonium chloride, and salts having anions such as sulfate, phosphate, carbonate, and acetate can be used. Furthermore, a water-soluble liquid in which the film-forming material dissolves less than in water, such as alcohols such as ethanol and propanol, or water-soluble polymers such as isobutylene-maleic anhydride ring-opening copolymer salts, can also be used.

[0119] In the adhesive composition for organic fibers of the present invention, the mixing mass ratio [(A):[(C)+(D)+(E))] (solid content equivalent) of "(A) rubber latex having an unsaturated diene" to "(C) aqueous compound having a (thermally dissociable blocked) isocyanate group, (D) epoxide compound, and (E) compound selected from the group consisting of polyphenol" is not particularly limited, but is preferably in the range of 100:5 to 100:300, more preferably in the range of 100:15 to 100:150, and even more preferably in the range of 100:20 to 100:70 (both of these mixing mass ratios are included). When the mixing mass ratio is 100:5 or more (when the ratio value is 20 or less), the ratio of "(A) rubber latex having an unsaturated diene" in the adhesive composition for organic fibers does not become too large, and the fracture resistance of the adhesive layer formed by the adhesive composition for organic fibers can be sufficiently maintained, and a decrease in adhesion under strain can be prevented. Furthermore, if the mixing mass ratio is 100:300 or less (if the ratio value is 1 / 3 or more), the ratio of the "(A) rubber latex having an unsaturated diene" in the adhesive composition for organic fibers will not be too low, and when the coated rubber composition that is the adherend of the organic fibers and the adhesive composition for organic fibers are co-vulcanized to bond them, the coated rubber composition that is the adherend and the "(A) rubber latex having an unsaturated diene" will be well miscible with each other, and as a result, the adhesion between the coated rubber composition that is the adherend and the adhesive composition for organic fibers will be sufficiently high.

[0120] Furthermore, the (A) rubber latex having an unsaturated diene, (B) polypeptide, (C) aqueous compound having a (thermally dissociable blocked) isocyanate group, (D) epoxide compound, and (E) polyphenol are preferably aqueous, since water, which causes less environmental pollution, can be used as a solvent.

[0121] [Organic fiber-rubber composite] The organic fiber-rubber composite of the present invention is characterized by using organic fibers coated with the adhesive composition for organic fibers of the present invention, and has the effects (1), (2), and (3) described above. The organic fiber cord-rubber composite of the present invention is characterized by using an organic fiber cord coated with the adhesive composition for organic fibers of the present invention, and has the effects (1), (2), and (3) described above. The organic fiber-rubber composite of the present invention will be described in detail with reference to FIG.

[0122] Fig. 4 is a cross-sectional schematic diagram showing an example of an organic fiber-rubber composite of the present invention. In the organic fiber-rubber composite 31 shown in Fig. 4, the outer surface in the outer diameter direction of an organic fiber cord 1 is coated with an adhesive layer 32 made of the organic fiber adhesive composition 2 of the present invention. The organic fiber cord 1 is then bonded to a coating rubber composition 33 located further outward in the outer diameter direction via the adhesive 32 made of the organic fiber adhesive composition 2, thereby forming the organic fiber-rubber composite 31 of the present invention.

[0123] In addition to the organic fiber-rubber composite (organic fiber cord-rubber composite), the rubber reinforcing material using the organic fiber adhesive composition of the present invention can also be in the form of a film, short fiber, nonwoven fabric, etc.

[0124] <<Organic fiber (especially organic fiber cord) of organic fiber-rubber composite>> The organic fiber (particularly, organic fiber cord) constituting the organic fiber-rubber composite of the present invention is as described in the section <Organic fiber (particularly, organic fiber cord)>.

[0125] <<Coating rubber composition of organic fiber-rubber composite>> On the other hand, the coating rubber composition constituting the organic fiber-rubber composite of the present invention is preferably a rubber component blended with compounding agents commonly used in the rubber industry. The rubber component is not particularly limited, and examples thereof include natural rubber, conjugated diene-based synthetic rubbers such as polyisoprene rubber (IR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR), as well as ethylene-propylene copolymer rubber (EPM), ethylene-propylene-diene copolymer rubber (EPDM), and polysiloxane rubber. Among these, natural rubber and conjugated diene-based synthetic rubber are preferred. These rubber components may be used alone or in combination.

[0126] <<Method of manufacturing organic fiber-rubber composites>> The organic fiber-rubber composite of the present invention is produced by coating an organic fiber (particularly an organic fiber cord) with the adhesive composition for organic fibers of the present invention to form an adhesive layer, and then co-vulcanizing and bonding the "(A) unsaturated diene-containing rubber latex" in the adhesive composition for organic fibers and the rubber component in the coating rubber composition, which is the adherend of the organic fiber.

[0127] The method for coating the organic fiber cord with the organic fiber adhesive composition according to the present invention is not particularly limited, and may include a method of immersing the organic fiber cord in the organic fiber adhesive composition, a method of applying the organic fiber adhesive composition to the organic fiber cord with a brush, a method of spraying the organic fiber adhesive composition to the organic fiber cord, etc., and an appropriate method can be selected as needed.

[0128] When coating the organic fiber cord with the adhesive composition for organic fibers, it is preferable to dissolve the adhesive composition for organic fibers in various solvents to reduce the viscosity, which facilitates coating. From an environmental perspective, it is preferable that the solvent for reducing the viscosity of the adhesive composition for organic fibers consists mainly of water.

[0129] Here, the thickness of the adhesive layer formed from the adhesive composition for organic fibers is not particularly limited, but is preferably 50 μm or less, and more preferably 0.5 μm or more and 30 μm or less. Furthermore, as the amount of adhesive composition deposited by the adhesive treatment increases, the adhesive durability under tire rolling tends to decrease. The reason for this is that the adhesive composition at the interface of the adhered fiber material has high rigidity, so it bears the stress caused by strain and undergoes relatively little deformation, but the deformation due to strain increases with increasing distance from the interface. Because the adhesive composition contains a higher amount of thermosetting condensate than the adhered rubber material, it is hard and brittle, and therefore prone to adhesive fatigue under repeated strain. For these reasons, the average thickness of the adhesive composition layer is preferably 50 μm or less, and more preferably 0.5 μm or more and 30 μm or less. The concentration of the adhesive composition for organic fibers impregnated into the organic fiber cord is not particularly limited, but is preferably 5.0 mass % or more and 25.0 mass % or less, and more preferably 7.5 mass % or more and 20.0 mass % or less, relative to the mass of the organic fiber cord (all values ​​are calculated as solid content).

[0130] The organic fibers coated with the adhesive composition for organic fibers are preferably dried, for example, at a temperature of 100°C or higher and 210°C or lower, and then heat-treated at a temperature higher than the glass transition temperature of the polymer chain of the organic fiber (typically, a temperature higher than the melting temperature of the polymer chain: -70°C and lower than the melting temperature of the polymer chain: -10°C). The reason why this is preferable is that if the temperature is equal to or higher than the glass transition temperature of the polymer chains of the organic fibers, the molecular mobility of the polymer chains of the organic fibers becomes good, and the adhesion promoter in the adhesive composition for organic fibers (e.g., (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group) and the polymer chains of the organic fibers can sufficiently interact with each other, thereby obtaining sufficient adhesive strength between the adhesive composition for organic fibers and the organic fibers. The organic fibers may be pretreated in advance with electron beam, microwave, corona discharge, plasma treatment, or the like.

[0131] In the organic fiber-rubber composite of the present invention, when the organic fiber is an organic fiber, the resin material may be in any form, such as a film, cord, cable, filament, filament chip, woven cord, or canvas. Cords formed by twisting together multiple filaments of the resin are particularly suitable for reinforcing rubber articles such as tires and conveyor belts. Furthermore, in such cords, the synthetic fibers preferably have a top twist and a bottom twist, with the twist coefficient of the bottom twist being 1,300 to 2,500 and the twist coefficient of the top twist being 900 to 1,800. In the present invention, the organic fiber cord-rubber composite is preferably a 66 nylon tire cord having a twist structure of 1,400 dtex / 2, a top twist of 39 turns / 10 cm, and a bottom twist of 39 turns / 10 cm, and the adhesive composition for organic fibers is adhered to the tire cord.

[0132] Finally, the organic fiber cord coated with the adhesive composition for organic fibers is bonded by co-vulcanizing the (A) rubber latex containing an unsaturated diene in the adhesive composition for organic fibers and the rubber component in the coating rubber composition that is the adherend for the organic fiber.

[0133] Examples of organic vulcanizing agents used in co-vulcanization of the rubber components in the coating rubber composition include sulfur, thiralium polysulfide compounds such as tetramethylthiralium disulfide and dipentamethylenethiralium tetrasulfide, 4,4-dithiomorpholine, p-quinonedioxime, p,p'-dibenzoquinonedioxime, and cyclic sulfur imides. Of these, sulfur is preferred. Furthermore, various compounding agents commonly used in the rubber industry, such as fillers such as carbon black, silica, and aluminum hydroxide, vulcanization accelerators, antioxidants, and softeners, can be appropriately blended into the rubber components in the coating rubber composition.

[0134] Furthermore, it goes without saying that the adhesive composition for organic fibers of the present invention also provides an adhesive effect in a bonding method characterized in that a vulcanizing agent contained in an adherend made of a synthetic resin material, such as an organic fiber cord, and / or an adherend made of a coated rubber composition migrates to the adhesive composition for organic fibers, and the migrated vulcanizing agent crosslinks the adhesive composition for organic fibers.

[0135] [tire] The tire of the present invention uses the organic fiber-rubber composite (or organic fiber cord-rubber composite) of the present invention, and has the above-mentioned effects (1), (2), and (3). Here, in the tire of the present invention, the organic fiber-rubber composite (particularly the organic fiber cord-rubber composite) can be used as, for example, a reinforcing layer around the belt such as a carcass, a belt, a belt reinforcing layer, or a flipper. Depending on the type of tire to be applied, the tire of the present invention may be obtained by molding an unvulcanized rubber composition and then vulcanizing it, or by molding a semi-vulcanized rubber that has been subjected to a pre-vulcanization process or the like and then further vulcanizing it. The tire of the present invention uses organic fibers treated with the adhesive composition described above in some locations on the tire, but other components are not particularly limited and known components can be used. The tire of the present invention is preferably a pneumatic tire, and the gas to be filled into the pneumatic tire may be normal air or air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, or helium.

[0136] The adhesive composition for organic fibers of the present invention and the organic fiber-rubber composite of the present invention described above can be applied to all kinds of rubber articles, such as conveyor belts, belts, hoses, air springs, etc., in addition to the tires. [Example]

[0137] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0138] <(A) Rubber Latex Having Unsaturated Diene> In the following comparative examples and examples, a vinylpyridine-styrene-butadiene copolymer latex (a synthetic rubber latex having an unsaturated diene) was used as the rubber latex having an unsaturated diene (A) in accordance with Comparative Example 1 described in JP-A-9-78045, which was prepared as follows. A 5-liter autoclave with a nitrogen atmosphere was charged with 130 parts by weight of deionized water and 4.0 parts by weight of potassium rosinate and dissolved. A monomer mixture consisting of 15 parts by weight of vinylpyridine monomer, 15 parts by weight of styrene, and 70 parts by weight of butadiene, and 0.60 parts by weight of t-dodecyl mercaptan were then charged and emulsified. The mixture was then heated to 50°C, and 0.5 parts by weight of potassium persulfate was added to initiate polymerization. After the reaction rate of the monomer mixture reached 90%, 0.1 parts by weight of hydroquinone was added to terminate the polymerization. Next, unreacted monomer was removed under reduced pressure, yielding a vinylpyridine-styrene-butadiene copolymer latex with a solids concentration of 41% by weight.

[0139] <(B) Polypeptide> In the following examples, the (B) polypeptide is Milk-derived polypeptide, "Promis HYDOROMILK" (solid content = 30% by mass) manufactured by Seiwa Kasei Co., Ltd. Soybean-derived polypeptide, product name "Promis WS-HF" (solid content = 25% by mass) manufactured by Seiwa Kasei Co., Ltd. "Promis Silk-1000F" (solid content = 6.5% by mass), a fibroin-derived polypeptide manufactured by Seiwa Kasei Co., Ltd. A fish scale-derived polypeptide, "Promis W32-U" (solid content = 20% by mass) manufactured by Seiwa Kasei Co., Ltd. "Promis W42" (solid content = 30% by mass), a pigskin-derived polypeptide manufactured by Seiwa Kasei Co., Ltd. A cationized milk-derived polypeptide, "N-[2-hydroxy-3-(trimethylammonio)propyl] chloride modified polypeptide, available from Seiwa Kasei Co., Ltd. under the trade name "Promis MILK-Q" (solids concentration = 30% by mass), was used as is.

[0140] <(C) Aqueous Compound Having a (Thermally Dissociable Blocked) Isocyanate Group> In the following Comparative Examples and Examples, the trade name "ELASTRON BN77" manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. [(C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group, blocking agent thermal dissociation temperature: approximately 160°C, pH: 8.0, solid content concentration: 31% by mass] was used as is as the aqueous compound having a (thermally dissociable blocked) isocyanate group (C).

[0141] <(D) Epoxide Compound> In the following comparative examples and examples, the (D) epoxide compound was a sorbitol polyglycidyl ether (trade name "Denacol EX-614B" manufactured by Nagase Chemtec Corporation) (molecular weight: 949, epoxy equivalent: 173, solids concentration: 100% by mass), which was diluted with deionized water to prepare an aqueous solution with a solids concentration of 10% by mass, and this aqueous solution was used to prepare the adhesive composition.

[0142] <(E) Polyphenols> In the following comparative examples and examples, (E) polyphenols manufactured by Tokyo Chemical Industry Co., Ltd. under the trade name "Lignin (alkali)" (CAS Number: 8061-51-6), manufactured by Sigma-Aldrich Co. LLC under the trade name "Lignin, alkali" (CAS Number: 8068-05-1), and manufactured by Kawamura Tsusho Co., Ltd. under the trade name "Mimosa" were diluted with deionized water to prepare aqueous solutions with a solids concentration of 10% by mass, and these aqueous solutions were used to prepare adhesive compositions.

[0143] <<Preparation of Latex Adhesive Composition (Comparative Example 1)>> The (A) rubber latex having an unsaturated diene and water were mixed in amounts adjusted to a solids concentration of 17% by mass, and then thoroughly stirred to obtain a latex adhesive composition (Comparative Example 1).

[0144] <<Preparation of Latex-Waterborne Urethane Adhesive Composition (Comparative Example 2)>> The (A) rubber latex having an unsaturated diene and the (C) aqueous compound having a (thermally dissociable blocked) isocyanate group were blended as shown in Table 2, and the amount of water was adjusted to give a solids concentration of the adhesive composition of 17 mass %, and the mixture was mixed, followed by sufficient stirring, to obtain a latex-aqueous urethane adhesive composition (Comparative Example 2).

[0145] <<Preparation of Latex-Epoxide Adhesive Composition (Comparative Example 3)>> The (A) rubber latex having an unsaturated diene and the (D) epoxide compound were blended as shown in Table 2, and the amount of water was adjusted to give a solids concentration of the adhesive composition of 17 mass %, and the mixture was then thoroughly stirred to obtain a latex-epoxide adhesive composition (Comparative Example 3).

[0146] <<Preparation of Latex-Polyphenol Adhesive Composition (Comparative Example 4)>> The (A) rubber latex having an unsaturated diene and the (E) polyphenol were blended as shown in Table 2, and the amount of water was adjusted to give a solids concentration of the adhesive composition of 17 mass %, and the mixture was then thoroughly stirred to obtain a latex-polyphenol adhesive composition (Comparative Example 4).

[0147] <<Preparation of adhesive compositions for organic fibers (Examples 1 to 17) according to one embodiment of the present invention>> As shown in Tables 2 and 3, each of the specified (A) rubber latex having an unsaturated diene, (B) polypeptide, (C) aqueous compound having a (thermally dissociable blocked) isocyanate group (Examples 1, 3, 6, 9, 12, and 15), (D) epoxide compound (Examples 2, 4, 7, 10, 13, and 16), and (E) polyphenol (Examples 5, 8, 11, 14, and 17) was blended in this order, and the amount of water was adjusted to give a solids concentration of the adhesive composition of 17% by mass. The mixture was then mixed and thoroughly stirred to obtain an adhesive composition for organic fibers (Examples 1 to 17) according to one embodiment of the present invention.

[0148] <Coating of tire cord with each adhesive composition for organic fibers> As the organic fiber cord, a tire cord made of polyethylene terephthalate with a twist structure of 1670 dtex / 2, a top twist number of 39 times / 10 cm, and a bottom twist number of 39 times / 10 cm was used. The tire cord was immersed in each of the organic fiber adhesive compositions of Comparative Examples 1 to 4 and Examples 1 to 17 so that the concentration of the organic fiber adhesive composition impregnated in the tire cord was 3.8 mass % relative to the mass of the organic fiber cord. Next, the tire cord was dried in the drying zone (150°C, 60 seconds), the resin was thermally cured in the hot zone while applying tension (0.8 kg / cord), and thermally cured in the normalization zone (240°C, 60 seconds) while the tension was released, to obtain tire cords coated with each of the organic fiber adhesive compositions of Comparative Examples 1 to 4 and Examples 1 to 17.

[0149] <Formation of tire cord-rubber composite> The tire cords coated with the adhesive compositions for organic fibers of Comparative Examples 1 to 4 and Examples 1 to 17 were embedded in an unvulcanized rubber composition and co-vulcanized at 155° C. for 20 minutes. The unvulcanized rubber composition used for coating was a rubber composition containing natural rubber, styrene-butadiene rubber, carbon black, vulcanization chemicals, and the like.

[0150] <Evaluation of workability of adhesive compositions for organic fibers> The adhesive compositions for organic fibers of Comparative Examples 1 to 4 and Examples 1 to 17 were evaluated for workability as follows.

[0151] <<Evaluation of mechanical stability (solidification rate)>> The mechanical stability (coagulation rate) of each of the adhesive compositions for organic fibers in Comparative Examples 1 to 4 and Examples 1 to 17 was measured in accordance with the method using a Maron mechanical stability tester for copolymer latex compositions (Maron stability tester No. 2312-II, manufactured by Kumagai Riki Kogyo Co., Ltd.) specified in JIS K6392-1995. In summary, each of the adhesive compositions for organic fibers of Comparative Examples 1 to 4 and Examples 1 to 17 was subjected to shear strain for 10 minutes at a compression load of 10 kg and a rotation speed of 1000 r / min using the rotor of the Maron mechanical stability tester, and the solidification rate (%) was evaluated from the amount of solidified material that was generated using the following formula. Coagulation rate % = (dry mass of coagulated material) / (mass of solid content of test adhesive liquid) × 100 A smaller value indicates better mechanical stability.

[0152] <<Evaluation of adhesion to squeeze rolls>> The polyethylene terephthalate tire cord, which is an organic fiber cord, was continuously treated for 2000 m in a dipping treatment machine storing each of the organic fiber adhesive compositions of Comparative Examples 1 to 4 and Examples 1 to 17, and the amount of each of the organic fiber adhesive compositions of Comparative Examples 1 to 4 and Examples 1 to 17 adhering to the squeeze roll was visually observed and evaluated on the following five-point scale. Extra large: Especially large Large: Many Medium: Moderate Few: Few Minor: Very little

[0153] <Evaluation of Adhesion Properties of Adhesive Compositions for Organic Fibers> The adhesive properties of each of the adhesive compositions for organic fibers of Comparative Examples 1 to 4 and Examples 1 to 17 were evaluated as follows.

[0154] <<Evaluation of adhesive strength>> The tire cord-rubber composites obtained using the adhesive compositions for organic fibers of Comparative Examples 1 to 4 and Examples 1 to 17 were pulled at a speed of 300 mm / min to peel the tire cords from the tire cord-rubber composites, and the peel resistance per tire cord was determined, which was taken as the adhesive strength (N / cord).

[0155] <<Evaluation of the adhesion state of coated rubber>> The tire cord peeled from the tire cord-rubber composite was visually observed for the state of adhesion of the coated rubber, and scored according to Table 1 below.

[0156] [Table 1]

[0157] <Results of workability evaluation and adhesion evaluation of adhesive compositions for organic fibers> The formulations of the adhesive compositions for organic fibers of Comparative Examples 1 to 4 and Examples 1 to 17, and the results of the workability evaluation and adhesiveness evaluation are shown in Tables 2 and 3 below.

[0158] [Table 2]

[0159] [Table 3]

[0160] <Columns for adhesive composition> A1: Vinylpyridine latex, vinylpyridine-styrene-butadiene copolymer latex synthesized by the above method, solid content = 41% by mass B1: Milk-derived polypeptide, manufactured by Seiwa Kasei Co., Ltd., product name "Promis HYDOROMILK", number average molecular weight = 600, solid content = 30% by mass B2: Soybean-derived polypeptide, manufactured by Seiwa Kasei Co., Ltd., product name "Promis WS-HF", number average molecular weight = 700, solid content = 25% by mass B3: Fibroin-derived polypeptide, manufactured by Seiwa Kasei Co., Ltd., product name "Promis Silk-1000F", number average molecular weight = 1000, solid content = 6.5% by mass B4: Fish scale-derived polypeptide, manufactured by Seiwa Kasei Co., Ltd., product name "Promis W32-U", number average molecular weight = 400, solid content concentration = 20% by mass B5: Pig skin-derived polypeptide, manufactured by Seiwa Kasei Co., Ltd., product name "Promis W42", number average molecular weight = 1000, solid content = 30% by mass B6: Trimethyl quaternary ammonium modified milk-derived polypeptide, manufactured by Seiwa Kasei Co., Ltd., product name "Promis MILK-Q", number average molecular weight = 800, solid content = 30% by mass C1: Aqueous urethane compound, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name "Elastron BN77" (F-2955D-1), an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group, blocking agent thermal dissociation temperature: approximately 160°C, pH: 8.0, solid content concentration = 31% by mass D1: Epoxide compound, sorbitol polyglycidyl ether, Nagase Chemtec Corporation, product name "Denacol EX-614B", molecular weight = 949, epoxy equivalent = 173, solid content concentration: used as an aqueous solution of 10 mass% E1: Polyphenol, manufactured by Tokyo Chemical Industry Co., Ltd., product name "Lignin (alkali)", solid content = 10% by mass

[0161] Tables 2 and 3 show that adhesive compositions containing, in addition to (A) a rubber latex having an unsaturated diene and (B) a polypeptide, one or more of (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group, (D) an epoxide compound, and (E) a polyphenol have good workability and good adhesion between organic fibers and the coating rubber composition. [Industrial Applicability]

[0162] According to the present invention, (1) By not using resorcinol, the environmental impact is low. (2) By suppressing the tackiness of the rubber latex, which is measured as the mechanical stability under shear strain of the adhesive liquid, it is possible to suppress the adhesion of the adhesive composition for organic fibers to rolls, etc., in the process of coating organic fibers with the adhesive composition for organic fibers and drying and heat curing, thereby improving workability. (3) Good adhesion between the organic fiber and the coating rubber composition; The adhesive composition for organic fibers that can achieve the above effects is provided. The present invention also provides an organic fiber-rubber composite using organic fibers coated with the adhesive composition for organic fibers, and a tire using the organic fiber-rubber composite. Therefore, the present invention can be used in industrial fields that manufacture rubber articles such as tires. [Explanation of symbols]

[0163] 1: Organic fiber cord 2: Adhesive composition for organic fibers 3: Dipping bath 4: Organic fiber cord coated with adhesive composition for organic fibers 5: Squeeze roll 6: Drying zone 7: Hot Zone 8: Normalization Zone 11: Rubber latex containing unsaturated diene 12: Polypeptide 13: Urethane resin formed from an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group 14: Activated isocyanate group 15: Part that is likely to interact with organic fibers 16: Parts that are difficult to diffuse into organic fibers 20:Latex-polypeptide protective film effect 21: Rubber co-vulcanization adhesive 22: Polypeptide-isocyanate crosslinking 23: Activated isocyanate crosslinking 24: Water-based urethane-organic fiber interface effect 31: Organic fiber-rubber composite 32: Adhesive layer made of adhesive composition for organic fibers 33: Coating rubber composition 40: Water-dispersible (thermally dissociable blocked) isocyanate compound, which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups. 41: Aromatic isocyanate - organic fiber diffusion effect

Claims

1. (A) a rubber latex having an unsaturated diene, (B) a polypeptide, and The following (C) to (E): (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group, (D) an epoxide compound, (E) Polyphenols and one or more compounds selected from the group consisting of: Does not contain resorcinol The adhesive composition for organic fibers is characterized in that the polypeptide has a number average molecular weight of 300 to 8,000.

2. The adhesive composition for organic fibers according to claim 1 , wherein the polypeptide is a polypeptide obtained by hydrolyzing a protein.

3. 3. The adhesive composition for organic fibers according to claim 1 or 2, wherein the aqueous compound having a (thermally dissociable blocked) isocyanate group (C) is a water-dispersible (thermally dissociable blocked) isocyanate compound (C-1) that is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups.

4. The adhesive composition for organic fibers according to claim 3, wherein the water-dispersible (thermally dissociable blocked) isocyanate compound (C-1), which is an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups, is a blocked product of methylene diphenyl diisocyanate.

5. 3. The adhesive composition for organic fibers according to claim 1 or 2, wherein the aqueous compound having a (thermally dissociable blocked) isocyanate group (C) is an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group (C-2).

6. The aqueous urethane compound (C-2) having a (thermally dissociable blocked) isocyanate group is (α) an organic polyisocyanate compound having 3 or more and 5 or less functional groups and a number average molecular weight of 2,000 or less; (β) a compound having 2 or more and 4 or less active hydrogen groups and a number average molecular weight of 5,000 or less; (γ) a thermally dissociable blocking agent, and (δ) a compound having at least one active hydrogen group and at least one anionic, cationic, or nonionic hydrophilic group; The mixing ratio of each of (α), (β), (γ) and (δ) to the total amount is (α) is 40% by mass or more and 85% by mass or less, (β) is 5% by mass or more and 35% by mass or less, (γ) is 5% by mass or more and 35% by mass or less, and (δ) is 5% by mass or more and 35% by mass or less, The reaction product after mixing and reacting is and a constituent ratio of (thermally dissociable blocked) isocyanate groups in the reaction product is 0.5 mass % or more and 11 mass % or less, when the molecular weight of the isocyanate group (—NCO) is 42.

7. The aqueous urethane compound (C-2) having a (thermally dissociable blocked) isocyanate group is represented by the following general formula (1): 【Chemistry 1】 [In formula (1), A is a residue of an organic polyisocyanate compound from which an active hydrogen group has been eliminated, X is a residue of a polyol compound having 2 or more and 4 or less hydroxyl groups and a number average molecular weight of 5,000 or less, from which an active hydrogen group has been eliminated; Y is a residue of the thermally dissociable blocking agent from which the active hydrogen group has been eliminated; Z is a residue of a compound having at least one active hydrogen group and at least one salt-forming group or a hydrophilic polyether chain, in which the active hydrogen group has been eliminated; n is an integer between 2 and 4, p + m is an integer between 2 and 4 (m≧0.25) The adhesive composition for organic fibers according to claim 5, wherein

8. The adhesive composition for organic fibers according to any one of claims 1 to 7, wherein the epoxide compound (D) has two or more epoxy groups in one molecule.

9. The adhesive composition for organic fibers according to any one of claims 1 to 8, wherein the (D) epoxide compound is a reaction product of a polyhydric alcohol and epichlorohydrin.

10. The adhesive composition for organic fibers according to any one of claims 1 to 9, wherein the (E) polyphenol is a plant-derived compound having multiple phenolic hydroxy groups in the molecule.

11. The adhesive composition for organic fibers according to any one of claims 1 to 10, wherein the (E) polyphenol is lignin or a derivative thereof.

12. An organic fiber-rubber composite, characterized by using organic fibers coated with the adhesive composition for organic fibers described in any one of claims 1 to 11.

13. An organic fiber cord-rubber composite, characterized by using an organic fiber cord coated with the adhesive composition for organic fibers according to any one of claims 1 to 11.

14. A tire characterized by using the organic fiber-rubber composite according to claim 12.

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