Adhesive agent composition, organic fibrous material, rubber article, organic fiber-rubber composite, and tire

Abstract

The present invention addresses the problem of providing an adhesive agent composition that can ensure desired adhesiveness without using resorcin and that does not compromise the workability during use. This adhesive agent composition, which is a solution to the problem, is characterized by comprising (A) a rubber latex having an unsaturated diene, and (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule, and further comprising (D) an aqueous component having a plurality of phenolic hydroxy groups in the molecule, (E) an aqueous component having a plurality of amino groups in the molecule, and (F) at least one compound selected from the group consisting of compounds including an amide bond structure.

Description

Adhesive composition, organic fiber material, rubber article, organic fiber-rubber composite, and tire

[0001] The present invention relates to an adhesive composition, an organic fiber material, a rubber article, an organic fiber-rubber composite, and a tire.

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

[0003] In addition, in the step of coating the organic fibers with the adhesive composition, a solvent is generally used to adjust the viscosity of the adhesive composition, 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 the organic fibers with the adhesive composition by immersion, it is necessary to adjust the viscosity of the adhesive composition to a low enough level that it can be applied by immersion.

[0004] Generally, components contained in aqueous adhesive compositions that are water-based, i.e., capable of dissolving or dispersing in water, must have a polar molecular structure. However, polymeric materials such as rubber and organic fibers that serve as adherends have low polarity, and adhesion becomes difficult when the difference between the polarity of the surface of the rubber or organic fibers and the polarity of the components contained in the adhesive composition becomes large. Therefore, in order to use the aqueous adhesive composition as an adhesive composition for rubber articles, the components contained in the aqueous adhesive composition must have polarity because they are aqueous. However, this requires controlling the polarity so that a difference in polarity with the adherend does not result in a decrease in adhesion. Therefore, aqueous adhesive compositions that can satisfy these contradictory requirements are preferably used.

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

[0006] An organic fiber cord 1 is unwound from a winding roll, transported by rolls, and placed in a dipping bath (dipping tank) 3 containing an adhesive composition 2, where it is immersed in the adhesive composition 2. The organic fiber cord 4 coated with the adhesive composition 2 is pulled out of the dipping bath 3, and excess adhesive composition 2 is removed by a squeeze roll 5. The organic fiber cord 4 coated with the adhesive composition 2 is then further transported by rolls, dried in a drying zone 6, stretched by application of tension in a hot zone 7 and subjected to thermal curing of the resin, and thermally cured in a normalization zone 8 while the tension is precisely adjusted to achieve the desired strength and elongation properties (normalization), air-cooled outside the zone, and then wound up on a take-up roll. In this manner, the organic fiber is coated with the adhesive composition.

[0007] As the adhesive composition, compositions containing a rubber latex component such as rubber cement have long been used. In particular, an RFL (resorcinol-formaldehyde-latex) adhesive composition obtained by aging a mixed liquid containing resorcinol, formaldehyde, and rubber latex was discovered, and subsequently adhesive compositions in which a specific adhesion promoter was mixed with the RFL adhesive composition have 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 adhering to the rubber substrate and adhering to the surface of a substrate with low polarity, such as organic fibers, and is widely used worldwide. In adhesion using the RFL adhesive composition, first, the rubber latex component is included to bond to the rubber substrate by co-vulcanization, and then, on the other hand, a phenolic resin component consisting of a condensate of resorcinol and formaldehyde, which is included as a component to improve adhesion to organic fiber substrates, firmly bonds to the substrate.

[0009] The reason why resorcinol is preferably used here is that it can provide a phenolic condensation resin, which is a resin type that has high fracture resistance and high adhesion to resin adherends, and the polar functional group introduced into the phenol ring to achieve water solubility is a hydroxyl group, which has relatively little 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 aging 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. As a result, it is presumed that the water-soluble resorcinol and formaldehyde condense in a resol-type condensation reaction in the presence of a base (see 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 (see Non-Patent Document 1).

[0011] This aging causes the latex to crosslink 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 processed in an apparatus such as that shown in FIG. 1, thereby reducing staining of the apparatus due to the adhesion of the adhesive composition.

[0012] As the adhesion promoter added to the RFL adhesive composition, an aqueous adhesion promoter, i.e., an adhesion promoter that is soluble or dispersible in water, 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.

[0013] Examples of 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, as adhesion promoters containing a water-soluble group, there have been proposed phenolic resins that dissolve in water in the presence of a basic substance, such as 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 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 from the viewpoint of reducing the environmental load.

[0016] In order to address this issue, various adhesive compositions using water as a solvent by using polyphenols that do not contain resorcinol have been investigated and proposed.

[0017] For example, adhesive compositions containing rubber latex and lignin resin (see Patent Document 7) and aqueous adhesive compositions based on rubber latex, polyphenols such as flavonoids, and aromatic polyaldehyde (see Patent Documents 8 and 9) are known as adhesive compositions that do not contain resorcinol or formaldehyde.

[0018] Furthermore, Patent Document 10 listed below discloses a diene copolymer latex containing an aliphatic polyaminoamide compound and a coating composition for offset printing paper using the same. However, the coating composition disclosed in Patent Document 10 is a coating composition for coating only one side of the resin surface, not both the rubber and the resin, and there is little knowledge about adhesive compositions containing polyacrylamide for bonding rubber and resin that do not contain resorcinol or formaldehyde.

[0019] Furthermore, Patent Document 11 below discloses a resin composition for printing ink containing a polyhydric acrylate monomer obtained by reacting polyglycerin with an alkylene oxide. Furthermore, Patent Document 12 below discloses an aqueous composition containing a polymerizable (meth)acrylate or (meth)acrylamide monomer having a hydrophilic group, characterized by the absence of a photoinitiator, a polymerization catalyst, and an organic solvent, but there is little disclosure of findings regarding aqueous adhesive compositions of these polyhydric acrylates and rubber latex.

[0020] US Patent No. 2,128,229 Specification JP 2005-263887 A JP 2006-37251 A JP 9-12997 A International Publication No. 97 / 013818 JP 2011-241402 A International Publication No. 2018 / 003572 International Publication No. 2013 / 017421 Special Publication No. 2016-528337 JP 8-34879 A JP 2008-045103 A Special Publication No. 2022-522769 A

[0021] Koichi Hakata, Network Polymer Vol. 31, No. 5, p. 252 (2010)

[0022] However, when the above-mentioned adhesive composition for organic fiber cords that does not contain resorcinol is used, the adhesiveness of the rubber latex, which is measured as the mechanical stability of the adhesive solution under shear strain, increases. As a result, for example, in the process of coating an organic fiber cord 1 with an adhesive composition 2 and drying and thermal curing it as shown in Figure 1, the adhesive composition 2 adheres more to the squeeze roll 5, the rolls in the drying zone 6, and the like, resulting in a new problem of poor workability in the process.

[0023] Furthermore, such adhesive compositions that do not contain resorcinol and formaldehyde (so-called rubber cements) do not suppress the tackiness of rubber latex unless they are coated with a resorcinol-formaldehyde condensate, and therefore adhesion to the device in particular tends to deteriorate due to the surface of the adhesive coating becoming rough. Furthermore, since no crosslinking is obtained between the latex component and the resorcinol-formaldehyde condensate, there is also the problem that the adhesion between the organic fiber and the coated rubber composition is reduced compared to conventional RFL adhesive compositions.

[0024] Furthermore, as in Patent Document 7, when an aqueous adhesive composition is produced by mixing a polyphenol mixed with rubber latex with an aromatic dialdehyde such as terephthalaldehyde or 2,5-furandicarboxaldehyde, which has low solubility in water, the aromatic dialdehyde is poorly soluble in water during production, resulting in insufficient workability. Furthermore, compared to a condensate of resorcinol and formaldehyde, which is water-soluble even without the addition of alkali, in the process of preparing the adhesive composition, a condensate of aromatics and aromatic dialdehydes, which generally has low water solubility, is made water-soluble by adding alkali to the phenolic group. As a result, the amount of base contained in the adhesive composition increases during the subsequent vulcanization bonding with the adhered rubber, which generally accelerates the vulcanization reaction of the included rubber latex, resulting in a problem of reduced adhesion due to over-vulcanization over time under heat.

[0025] Furthermore, the above-mentioned adhesive compositions not containing resorcinol have the problem of reducing the cord strength of organic fiber cords coated with the adhesive compositions.

[0026] Therefore, an object of the present invention is to provide an adhesive composition that can ensure desired adhesion without using resorcinol and does not impair workability during use, as well as an organic fiber material, a rubber article, an organic fiber-rubber composite, and a tire that use the same.

[0027]

[0006] In order to solve the above problems, the present inventors conducted extensive research into the composition of adhesive compositions, and as a result, discovered that by blending a predetermined rubber latex with an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule, and further blending one or more of an aqueous component having multiple phenolic hydroxy groups in the molecule, an aqueous component having multiple amino groups in the molecule, and a compound containing an amide bond structure, it is possible to obtain an adhesive composition that improves adhesion without using resorcinol and does not impair workability during use, thereby completing the present invention. That is, the adhesive composition, organic fiber material, rubber article, organic fiber-rubber composite, and tire of the present invention are generally configured as follows.

[0028] [1] An adhesive composition comprising: (A) a rubber latex having an unsaturated diene; and (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule; and further comprising one or more compounds selected from the group consisting of the following (D) to (F): (D) an aqueous component having multiple phenolic hydroxy groups in the molecule, (E) an aqueous component having multiple amino groups in the molecule, and (F) a compound containing an amide bond structure.

[0029] [2] The adhesive composition according to [1], further comprising (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group.

[0030] [3] The adhesive composition according to [1] or [2], wherein the (A) rubber latex having an unsaturated diene comprises at least one selected from the group consisting of natural rubber (NR), isoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), halogenated butyl rubber, acrylonitrile-butadiene copolymer rubber (NBR), and vinylpyridine-styrene-butadiene copolymer rubber (Vp).

[0031] [4] The adhesive composition according to any one of [1] to [3], wherein the aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule is an aqueous compound containing a polyether structure in the molecule.

[0032] [5] The adhesive composition according to any one of [1] to [4], wherein the (B) aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in its molecule is (B-1) a compound containing two or more polymerizable (meth)acrylate structures and a polyglycerin structure in its molecule, (B-2) a compound containing two or more polymerizable (meth)acrylamide structures and a main chain-linked ether structure in its molecule, (B-3) a compound containing two or more polymerizable (meth)acrylamide structures and a main chain-linked amine structure in its molecule, or (B-4) a compound containing two or more polymerizable (meth)allyl structures and a dimethylammonium chloride structure in its molecule.

[0033] [6] The adhesive composition according to any one of [1] to [5], wherein the (D) aqueous component having a plurality of phenolic hydroxy groups in the molecule is a plant-derived component having a plurality of phenolic hydroxy groups in the molecule.

[0034] [7] The adhesive composition according to [6], wherein the aqueous component (D) having a plurality of phenolic hydroxy groups in the molecule is lignin, tannin, tannic acid, a flavonoid, or a derivative thereof.

[0035] [8] The adhesive composition according to [7], wherein the aqueous component (D) having a plurality of phenolic hydroxy groups in the molecule is a derivative of lignosulfonic acid.

[0036] [9] The adhesive composition according to any one of [1] to [8], wherein the (E) aqueous component having a plurality of amino groups in the molecule is (E-1) a polypeptide having an amino group, (E-2) a polyetheramine, (E-3) a polyethyleneimine, or (E-4) a polyamidoamine.

[0037]

[10] The adhesive composition according to [9], wherein the aqueous component (E) having a plurality of amino groups in the molecule is polylysine.

[0038]

[11] The adhesive composition according to any one of [1] to

[10] , wherein the (F) compound having an amide bond structure is a polymer of (meth)acrylamide or a copolymer containing (meth)acrylamide and another polymerizable monomer.

[0039]

[12] The adhesive composition according to any one of [2] to

[11] , wherein the aqueous compound (C) having a (thermally dissociable blocked) isocyanate group is a water-dispersible (thermally dissociable blocked) isocyanate compound (C-1) formed from an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups.

[0040]

[13] The adhesive composition according to

[12] , wherein the (C-1) water-dispersible (thermally dissociable blocked) isocyanate compound formed as 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.

[0041]

[14] The adhesive composition according to any one of [2] to

[11] , 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).

[0042]

[15] The aqueous urethane compound having a (thermally dissociable blocked) isocyanate group (C-2) comprises: (α) an organic polyisocyanate compound having 3 to 5 functional groups and a number average molecular weight of 2,000 or less; (β) a compound having 2 to 4 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 hydrophilic group that is anionic, cationic, or nonionic, in a mixing ratio of each of (α), (β), (γ), and (δ) relative to the total amount of (α), (β), (γ), and (δ): 40% by mass or more and 85% by mass or less for (α), 5% by mass or more and 35% by mass or less for (β), 5% by mass or more and 35% by mass or less for (γ), and 5% by mass or more and 35% by mass or less for (δ). and reacting the components so that 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.

[0043]

[16] The aqueous urethane compound (C-2) having a (thermally dissociable blocked) isocyanate group is represented by the following general formula (1): The adhesive composition according to

[14] or

[15] , represented by formula (1): [in which A represents a residue of an organic polyisocyanate compound from which an active hydrogen group has been eliminated, X represents a residue of a polyol compound having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less from which an active hydrogen group has been eliminated, Y represents a residue of a thermally dissociable blocking agent from which an active hydrogen group has been eliminated, Z represents a residue of a compound having at least one active hydrogen group and at least one salt-forming group or a hydrophilic polyether chain from which an active hydrogen group has been eliminated, n represents an integer of 2 to 4, and p+m represents an integer of 2 to 4 (m≧0.25)].

[0044]

[17] The adhesive composition according to any one of [1] to

[16] , which does not contain resorcinol.

[0045]

[18] The adhesive composition according to any one of [1] to

[17] , which does not contain a photoinitiator.

[0046]

[19] The adhesive composition according to any one of [1] to

[18] , which is for bonding to rubber.

[0047]

[20] The adhesive composition according to any one of [1] to

[19] , which is for bonding to organic fibers.

[0048]

[21] The adhesive composition according to any one of [1] to

[20] , which is for bonding rubber and organic fibers.

[0049]

[22] An organic fiber material comprising organic fibers and an adhesive layer covering the surface of the organic fibers, wherein the adhesive layer is made of the adhesive composition according to any one of [1] to

[21] .

[0050]

[23] The organic fiber material according to

[22] , wherein the organic fiber is an organic fiber cord formed by twisting together a plurality of filaments.

[0051]

[24] The organic fiber material according to

[23] , wherein the organic fiber cord is formed by first twisting and second twisting, the fiber thickness of the twisted cord is 100 dtex to 5000 dtex, and the number of twists is 10 to 50 times / 10 cm for the first twist and 10 to 50 times / 10 cm for the second twist.

[0052]

[25] The organic fiber material according to

[23] or

[24] , wherein the adhesive layer has a dry mass of 0.5 to 6.0 mass% of the mass of the organic fiber cord.

[0053]

[26] The organic fiber material according to any one of

[22] to

[25] , wherein the organic fiber is made of a polyester resin.

[0054]

[27] A rubber article, characterized by being reinforced with the organic fiber material according to any one of

[22] to

[26] .

[0055]

[28] An organic fiber-rubber composite, which is a composite of organic fiber and rubber, characterized in that the organic fiber is coated with the adhesive composition according to any one of [1] to

[21] .

[0056]

[29] A tire characterized by using the organic fiber-rubber composite according to

[28] .

[0057] According to the present invention, it is possible to provide an adhesive composition that can ensure desired adhesion without using resorcinol and does not impair workability during use, as well as an organic fiber material, a rubber article, an organic fiber-rubber composite, and a tire that use the same.

[0058] 1 is a schematic diagram showing an example of a process for coating an organic fiber cord with an adhesive composition by dipping. 2 is a schematic cross-sectional view showing an example of an organic fiber-rubber composite of the present invention.

[0059] The adhesive composition, organic fiber material, rubber article, organic fiber-rubber composite, and 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.

[0060] [Definitions] The compounds described herein may be derived in part or in whole from fossil resources, biological resources such as plant resources, recycled resources such as used tires, or a mixture of two or more of fossil, biological, and recycled resources.

[0061] When ranges are expressed herein, unless otherwise specified, the ends of the range are included within the range.

[0062] [Adhesive Composition] The adhesive composition of the present invention is characterized by comprising (A) a rubber latex having an unsaturated diene, and (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule, and further comprising one or more compounds selected from the group consisting of (D) an aqueous component having a plurality of phenolic hydroxy groups in the molecule, (E) an aqueous component having a plurality of amino groups in the molecule, and (F) a compound having an amide bond structure.

[0063] The adhesive composition of the present invention, having the above-described structure, can achieve good adhesion without using resorcinol, and in particular, can ensure good adhesion between organic fibers and the coating rubber composition. In the adhesive composition of the present invention, (A) the rubber latex having an unsaturated diene can improve the adhesion between the adhesive composition and the rubber substrate, thereby contributing to improved adhesion. Furthermore, by using (A) the rubber latex having an unsaturated diene in combination with components (D) to (F), which are (D) an aqueous component having multiple phenolic hydroxy groups in the molecule, (E) an aqueous component having multiple amino groups in the molecule, and (F) a compound containing an amide bond structure, the tack of the rubber latex, measured as the mechanical stability of the adhesive liquid under shear strain, can be suppressed. This can suppress adhesion of the adhesive composition to rolls and the like during the process of coating organic fibers with the adhesive composition and drying and thermal curing, thereby improving workability.

[0064] Furthermore, when the adhesive composition of the present invention is combined with (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in its molecule, and organic fibers are coated with the adhesive composition and then dried and heat-cured, the adhesive composition undergoes a Michael addition reaction with the above-mentioned components (D) to (F), or component (B) wetted within component (F) crosslinks to form a mutually wetting network. This increases the interaction between the components, further stabilizing the dispersion state of the rubber latex (A) containing an unsaturated diene. This further improves workability, particularly during the process of thermally curing organic fibers with the adhesive composition, by suppressing adhesion of the adhesive composition to rolls and the like. Furthermore, the adhesive strength at high temperatures is also improved and excellent. Therefore, the adhesive composition of the present invention can achieve the desired adhesive properties without using resorcinol, while also ensuring good workability during use.

[0065] Furthermore, the adhesive composition of the present invention does not require the use of resorcinol, which reduces the environmental impact. Therefore, the adhesive composition of the present invention can be one that does not contain resorcinol. Furthermore, the adhesive composition of the present invention preferably does not contain formaldehyde. In this case, the environmental impact can be further reduced. Furthermore, the adhesive composition of the present invention preferably does not contain a photoinitiator. In this case, adhesion to organic fibers can be achieved by heating rather than by light.

[0066] Furthermore, although not particularly limited, the adhesive composition of the present invention preferably further contains (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group. In this case, excellent adhesive properties and mechanical stability can be achieved even in the absence of formaldehyde and resorcinol.

[0067] The adhesive composition of the present invention has high adhesion to rubber, making it preferable as an adhesive composition for bonding to rubber. Furthermore, the adhesive composition of the present invention has high adhesion to organic fibers, making it preferable as an adhesive composition for bonding to organic fibers. Furthermore, the adhesive composition of the present invention has high adhesion to both rubber and organic fibers, making it even more preferable as an adhesive composition for bonding rubber to organic fibers. The adhesive composition of the present invention is particularly useful when applied to organic fiber cords, as described below.

[0068] (A) Rubber Latex Having Unsaturated Diene In the adhesive composition of the present invention, examples of the (A) rubber latex having unsaturated diene include synthetic rubber latex having unsaturated diene and natural rubber latex.

[0069] The synthetic rubber latex having an unsaturated diene in the adhesive composition of the present invention means a synthetic rubber latex containing an unsaturated diene that is vulcanizable with sulfur.

[0070] In one embodiment of the present invention, the (A) rubber latex having an unsaturated diene contained in the adhesive composition is a component for bonding the adhesive layer of the adhesive composition to the coated rubber composition, which is the adherend, similar to the rubber cement described above. The (A) rubber latex having an unsaturated diene is compatible with the rubber polymer contained in the coated rubber composition, which is the adherend, and further, the unsaturated diene moieties co-vulcanize to form a rubber co-vulcanization bond. As a result, the adhesive composition of the present invention containing the (A) rubber latex having an unsaturated diene can, for example, provide good adhesion between an organic fiber cord and the coated rubber composition.

[0071] The (A) rubber latex having an unsaturated diene is not limited, but specific examples include natural rubber (NR) latex, and latexes of synthetic rubbers such as isoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), halogenated butyl rubber, acrylonitrile-butadiene copolymer rubber (NBR), and vinylpyridine-styrene-butadiene copolymer rubber (Vp). These may be used alone or in combination of two or more. When the (A) rubber latex having an unsaturated diene contains at least one selected from the group consisting of natural rubber (NR), isoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), halogenated butyl rubber, acrylonitrile-butadiene copolymer rubber (NBR), and vinylpyridine-styrene-butadiene copolymer rubber (Vp), when the adhesive composition is used on organic fibers, the adhesion between the organic fibers and the coating rubber composition becomes better.

[0072] Among the above, vinylpyridine-styrene-butadiene copolymer rubber latex is preferred. Vinylpyridine-styrene-butadiene copolymer rubber latex is a rubber latex that has been widely used in adhesive compositions and articles such as tires, and in the adhesive composition of the present invention, it also provides good bonding between the adhesive layer and the adhered rubber, and has the advantages of being relatively soft and flexible, which imparts strain relaxation due to rubber elasticity to the adhesive layer, thereby increasing fracture resistance and also making it possible to accompany deformation of the organic fiber cord.

[0073] Furthermore, the content (solids content) of the (A) rubber latex having an unsaturated diene relative to the total solids in the adhesive composition of the present invention is not particularly limited, but is preferably 25% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. Furthermore, the content of the (A) rubber latex having an unsaturated diene is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. When the content of the (A) rubber latex having an unsaturated diene is 50% by mass or more, the compatibility of the rubber polymers of the rubber composition to be adhered and the rubber latex contained in the adhesive composition becomes more appropriate, resulting in a more excellent adhesion state of the coating rubber in the organic fiber-rubber composite. On the other hand, when the content of the (A) rubber latex having an unsaturated diene is 95% by mass or less, the amount of the coating component that suppresses the adhesion of the latex contained as another component in the adhesive composition can be secured to a relatively constant level or more, compared to a rubber cement, and the mechanical stability of the adhesive liquid under shear strain can be obtained, and in the step of coating the adhesive composition on a fiber material to be adhered, adhesion of the adhesive composition to an apparatus such as that shown in Fig. 1 can be suppressed. Furthermore, the problem of the surface of the coated adhesive composition becoming rough and the adhesion to the coating rubber composition being reduced is less likely to occur, thereby improving adhesion.

[0074] The rubber latex (A) having an unsaturated diene can be obtained, for example, by dissolving an emulsifier such as potassium rosinate in water, adding a mixture of monomers thereto, and then adding an electrolyte such as sodium phosphate and a peroxide as a polymerization initiator to carry out polymerization, and then, after a predetermined conversion rate is reached, adding a charge transfer agent to terminate the polymerization, and then removing the remaining monomers. It is also preferable to use a chain transfer agent during the polymerization.

[0075] The emulsifier is used to emulsify a monomer mixture in an aqueous system, and 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 naphthalene sulfonate, sulfate esters of higher alcohols, alkylbenzene sulfonates, and aliphatic sulfonates, or nonionic surfactants such as alkyl esters, alkyl ethers, and alkylphenyl ethers of polyethylene glycol. Among these emulsifiers, metal salts of rosin acid, particularly alkali metal salts of rosin acid, are preferred. These emulsifiers may be used alone, i.e., alone, or in combination with two or more other emulsifiers. Rosin acid is a mixture of resin acids with similar chemical structures, primarily consisting of tricyclic diterpenes obtained from pine resin and the like. These resin acids have three ring structures, two double bonds, and one carboxyl group, and the double bond portion has a highly reactive functional group that can be esterified with the carboxyl group portion and the methylol terminal of an unsaturated carboxylic acid or a resol-type phenolic resin. 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 monomers used in latex polymerization.

[0076] Examples of the polymerization initiator that can be used include water-soluble initiators such as potassium persulfate, sodium persulfate, and ammonium persulfate, redox initiators, and oil-soluble initiators such as benzoyl peroxide. Among these, potassium persulfate is preferred.

[0077] Examples of the chain transfer agent that can be used 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. Of these, t-dodecyl mercaptan is preferred. The amount of such a chain transfer agent used is usually 0.01 to 5 parts by mass, and preferably 0.1 to 3 parts by mass, per 100 parts by mass of all monomers used in latex polymerization.

[0078] In addition to the above components, the latex may contain, as necessary, general-purpose additives such as antiaging agents such as hindered phenols, silicone-based, higher alcohol-based, or mineral oil-based antifoaming agents, reaction terminators, antifreezing agents, etc. The components (B) to (F) of the present invention can be added to the latex in advance, and in that case, they are considered to be included in the composition consisting of (A) to (F) in the adhesive composition of the present invention.

[0079] --Vinylpyridine-styrene-butadiene copolymer rubber latex-- The vinylpyridine-styrene-butadiene copolymer rubber latex is a terpolymer of a vinylpyridine-based monomer, a styrene-based monomer, and a conjugated diene-based butadiene monomer, and may further contain other monomers copolymerizable with these monomers.

[0080] Here, the vinylpyridine monomer includes vinylpyridine and substituted vinylpyridines in which hydrogen atoms in the vinylpyridine are substituted with substituents. Examples of such vinylpyridine monomers include 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, and 5-ethyl-2-vinylpyridine, and among these, 2-vinylpyridine is preferred. These vinylpyridine monomers may be used alone or in combination of two or more.

[0081] 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.

[0082] 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.

[0083] The vinylpyridine-styrene-butadiene copolymer rubber latex can be synthesized by a known method, specifically, for example, the method described in JP-A-9-78045, which was studied by the present inventors. By using these methods, various compositions and intra-particle structures can be imparted to the same particle of the vinylpyridine-styrene-butadiene copolymer rubber latex, such as copolymers having uniform or different composition ratios.

[0084] 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. In addition, 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 the unsaturated diene-containing rubber latex (A) in the adhesive composition of the present invention.

[0085] In the vinylpyridine-styrene-butadiene copolymer rubber latex, the monomer ratio of vinylpyridine:styrene:butadiene is not particularly limited, but it is preferable that the copolymer constituting the vinylpyridine-styrene-butadiene copolymer particles contains a copolymer obtained by polymerizing a monomer mixture consisting of 5 to 20% by mass of vinylpyridine, 10 to 40% by mass of styrene, and 45 to 75% by mass of butadiene. A vinylpyridine content of 5% by mass or more provides an appropriate amount of pyridine moieties that have a vulcanization-accelerating effect within the rubber component, and the increased degree of crosslinking by sulfur further improves the adhesive strength of the entire adhesive layer. A vinylpyridine content of 20% by mass or less prevents the degree of crosslinking of the rubber from becoming over-vulcanized, resulting in a hard adhesive. Furthermore, a styrene content of 10% by mass or more provides sufficient strength for the latex particles and adhesive layer, further improving adhesive strength. A styrene content of 40% by mass or less leads to adequate co-vulcanization between the adhesive layer and the adhered rubber, while still ensuring 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. The composition ratio of the vinylpyridine:styrene:butadiene monomer mixture can be suitably set to, for example, 15:15:70.

[0086] In the present invention, as the (A) rubber latex having an unsaturated diene, natural rubber latex can be used in addition to synthetic rubber latex having an unsaturated diene. The natural rubber latex is not particularly limited, and examples thereof that can be used include field latex, ammonia-treated latex, centrifugal concentrated latex, deproteinized latex treated with a surfactant or enzyme, and combinations thereof. Among these, it is preferable to use field latex.

[0087] <(B) Aqueous Compound Having Two or More Polymerizable (Meth)acrylate Structures, (Meth)acrylamide Structures, or (Meth)allyl Structures in the Molecule> The adhesive composition of the present invention comprises (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule, and is less susceptible to deterioration due to hydrolysis of functional groups caused by moisture, resulting in superior shelf stability (pot life) of the adhesive composition compared to, for example, water-soluble epoxide compounds. Furthermore, the aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule has low reactivity toward radical polymerization at room temperature, and therefore does not cause an increase in liquid viscosity due to crosslinking of the adhesive composition in aqueous solution. This results in superior stability during the coating process in which the adhesive composition is applied to an organic fiber cord, and the composition can undergo a radical reaction by heating in the drying and curing process of the subsequent adhesive treatment process. For this reason, the adhesive composition of the present invention, which contains (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule, has the effect of reducing adhesion to rolls in an oven during the curing step of the adhesive treatment process, and also has the effect of improving the adhesive strength of the adhesive composition at high temperatures of 100°C or higher.

[0088] The polymerizable (meth)acrylate structure may include a (meth)acryloyloxy group (CH ２ =CH-CO-O-, CH ２ =C(CH ３)-CO-O-), and the polymerizable (meth)acrylamide structure includes a (meth)acryloylamino group (CH ２ =CH-CO-NH-, CH ２ =C(CH ３ )-CO-NH-), and the polymerizable (meth)allyl structure includes a (meth)allyl group (CH ２ =CH-CH ２ -, CH ２ =C(CH ３ )-CH ２ -) etc.

[0089] The aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule has a structure that imparts hydrophilicity to the molecule. Specific examples of the structure include, but are not limited to, a structure containing a main chain linking ether bond, a structure containing a main chain linking amine bond, a structure in which a polyol compound and a hydroxyl group-containing acrylic monomer are urethane-modified with an isocyanate compound, and a structure in which a reactive group of an acrylic monomer is introduced into an acrylic polymer.

[0090] As the (B) aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in its molecule, an aqueous compound having a polyether structure in its molecule is one of the preferred structures because the hydrophilicity of the ether group confers water solubility. When the (B) aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in its molecule is an aqueous compound having a polyether structure in its molecule, the (B) aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in its molecule can be mixed with the (A) adhesive composition containing rubber latex, which is an aqueous solvent, without separation from the aqueous phase. Furthermore, aqueous compounds having a polyether structure in their molecule are nonionic and miscible with aromatic hydrocarbon-based solvent systems, and therefore have a high affinity for organic fiber tire cords having aromatic hydrocarbons in their molecular skeleton. The polyether structure in the molecule may contain other functional groups, such as acidic groups such as carbonate, sulfate, sulfonate, sulfinate, phosphate, phosphonate, and phosphinate groups, hydroxyl groups, amino groups, amine groups, and thiol groups.

[0091] In this way, the aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule contains a structure that imparts hydrophilicity in the molecule, thereby making it possible to prepare a uniform adhesive composition liquid using water as a solvent. Furthermore, the aqueous compound (B) can be combined with other components of the adhesive composition, such as the aqueous component (D) having multiple phenolic hydroxy groups in the molecule, the aqueous component (E) having multiple amino groups in the molecule, and the compound (F) containing an amide bond structure, to wet in water and form networks in water that penetrate each other.

[0092] The aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in its molecule can be obtained, for example, by reacting an α,β-unsaturated acid with a compound that forms the main chain skeleton structure. Furthermore, when two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures (i.e., polymerizable functional groups) are introduced per molecule, the compound becomes capable of crosslinking by an addition reaction. For example, as the aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in its molecule, a polyfunctional monomer such as a bifunctional, trifunctional, tetrafunctional, pentafunctional, hexafunctional, heptafunctional, octafunctional, nonafunctional, or decafunctional monomer can be used. However, the introduction of a large number of hydrophobic (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures (functional groups) also reduces solubility in aqueous solutions. Therefore, the aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule is not particularly limited, but preferably has 2 to 5 polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures per molecule.

[0093] The (B) aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures or (meth)allyl structures in the molecule is, for example, a compound having a main chain ether derived from a compound having a main chain skeleton structure such as trimethylolpropane, pentaerythritol, xylitol, diglycerol, triglycerol, dipentaerythritol, sorbitol, (poly)glycerin, diethylene glycol, aliphatic polyether, polyethylene glycol, polypropylene glycol, etc., and an aliphatic spacer (CH ２ CH ２ or a main chain-linked amine and an aliphatic spacer (CH ２ CH ２It is preferable that the aqueous compound (B) contains a skeleton structure containing units in which (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures are linked together, and two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule. Alternatively, the aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule is diallyldimethylammonium chloride, or a mixture of diallyldimethylammonium chloride and acrylamide, allylamine, dimethylamine, epichlorohydrin, maleic acid, SO ２ and two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures or (meth)allyl structures in the molecule.

[0094] The aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule is particularly preferably (B-1) a compound containing two or more polymerizable (meth)acrylate structures and a polyglycerin structure in the molecule, (B-2) a compound containing two or more polymerizable (meth)acrylamide structures and a main chain-linked ether structure in the molecule, (B-3) a compound containing two or more polymerizable (meth)acrylamide structures and a main chain-linked amine structure in the molecule, or (B-4) a compound containing two or more polymerizable (meth)allyl structures and a dimethylammonium chloride structure in the molecule. When the (B) aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule is (B-1) a compound containing two or more polymerizable (meth)acrylate structures and a polyglycerin structure in the molecule, (B-2) a compound containing two or more polymerizable (meth)acrylamide structures and a main chain-linked ether structure in the molecule, (B-3) a compound containing two or more polymerizable (meth)acrylamide structures and a main chain-linked amine structure in the molecule, or (B-4) a compound containing two or more polymerizable (meth)allyl structures and a dimethylammonium chloride structure in the molecule, the adhesive composition provides better adhesion between the organic fiber and the coating rubber composition when used with the organic fiber.

[0095] In the compound (B-1) containing two or more polymerizable (meth)acrylate structures and a polyglycerin structure in the molecule, the constituent polyglycerin preferably has an average degree of polymerization of 2 to 20, more preferably 4 to 20. There are no particular restrictions on the production method, but it can be obtained by adding an alkylene oxide (ethylene oxide, propylene oxide, etc.) to the hydroxyl group of polyglycerin and then reacting the terminal hydroxyl group with acrylic acid or methacrylic acid. Specifically, SA-TE60, a polyglycerin-based (meth)acrylate manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., or the like can be used.

[0096] The compound (B-2) containing two or more polymerizable (meth)acrylamide structures and a main chain-linked ether structure in the molecule includes compounds represented by the following structural formula: N,N'-{[(2-acrylamido-2-[(3-acrylamidopropoxy)methyl]propane-1,3-diyl)bis(oxy)]bis(propane-1,3-diyl)}diacrylamide represented by the following structural formula: Examples of commercially available products that can be used include FOM-03006 and FOM-03008 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0097] The compound (B-3) containing two or more polymerizable (meth)acrylamide structures and a main chain-linked amine structure in the molecule includes compounds represented by the following structural formula: N,N',N''-triacryloyldiethylenetriamine represented by the following structural formula: Examples of polyfunctional (meth)acrylamide compounds include N,N',N'',N'''-tetraacryloyltriethylenetetramine, and commercially available products such as FOM-03007 and FOM-03009 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. can be used.

[0098] The compound (B-4) containing two or more polymerizable (meth)allyl structures and a dimethylammonium chloride structure in the molecule includes compounds represented by the following structural formula: Examples of commercially available products include DADMAC manufactured by Osaka Sword Co., Ltd. and D2003 manufactured by Tokyo Chemical Industry Co., Ltd., and further, a solution of its polymer, poly(diallyldimethylammonium chloride) manufactured by Sigma-Aldrich Japan LLC, can also be used.

[0099] The content (solids content) of the (B) aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule relative to the total solids content of the adhesive composition is not particularly limited, but is preferably 0.3% by mass or more, and more preferably 0.7% by mass or more. Furthermore, the content of the (B) aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule is preferably 7% by mass or less, and more preferably 3% by mass or less. When the content of the (B) aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule is 0.3% by mass or more, the adhesive composition can be combined with the other components of the adhesive composition, namely, (D) an aqueous component having multiple phenolic hydroxy groups in the molecule, (E) an aqueous component having multiple amino groups in the molecule, and (F) a compound containing an amide bond structure, to wet in water and form a network in which each component penetrates into the other components in water. Furthermore, if the content of (B) the aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures or (meth)allyl structures in the molecule is 7 mass % or less, it becomes possible to ensure that the amounts of other components such as (A) the rubber latex and components (D) to (F) blended into the adhesive composition are at least a certain level relative to one another, resulting in better adhesion to the adherend rubber.

[0100] <(D) Aqueous Component Having Multiple Phenolic Hydroxy Groups in the Molecule> One embodiment of the adhesive composition of the present invention comprises (A) a rubber latex having an unsaturated diene, (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule, and (D) an aqueous component having multiple phenolic hydroxy groups in the molecule.

[0101] The aqueous component (D) having a plurality of phenolic hydroxy groups in the molecule is preferably a plant-derived aqueous component having a plurality of phenolic hydroxy groups in the molecule, in which case, when the adhesive composition is used on organic fibers, the adhesion between the organic fibers and the coating rubber composition is improved.

[0102] The plant-derived aqueous component having multiple phenolic hydroxy groups in the molecule is preferably a plant-derived polymer having multiple phenolic hydroxy groups in the molecule, and preferably a water-soluble polyphenol. Specific examples include polyphenols such as lignin, tannin, tannic acid, flavonoids, and derivatives thereof. In this case, when the adhesive composition is used on organic fibers, the adhesion between the organic fibers and the coating rubber composition is further improved.

[0103] The aqueous component (D) having multiple phenolic hydroxy groups per molecule (also referred to as "polyphenols") chemically or physically adsorbs to latex particles of the rubber latex (A) having an unsaturated diene, similar to the rosin acid salt used as a latex emulsifier, and can function as a dispersant for disperse dyes due to the phenolic hydroxy groups. By stably dispersing each particle, the aqueous component (D) having multiple phenolic hydroxy groups per molecule effectively improves the shelf stability (pot life) and mechanical stability of the adhesive composition. Furthermore, the aqueous component (D) having multiple phenolic hydroxy groups per molecule acts as a phenolic antioxidant, suppressing oxidation degradation at the unsaturated diene moieties of the rubber latex (A) having an unsaturated diene contained in the adhesive composition. This prevents the reduction of the unsaturated diene content on the adhesive composition surface over time due to radical oxidation reactions caused by heat or light. Therefore, when the aqueous component (D) having multiple phenolic hydroxy groups per molecule is used in an adhesive composition, adhesion between the organic fiber and the coating rubber composition is reduced over time, resulting in good adhesion.

[0104] 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 (see, for example, Japanese Patent Application Laid-Open No. 07-53858). However, there is little knowledge about producing aqueous adhesive compositions that do not contain resorcinol, and in particular, little knowledge about producing aqueous adhesive compositions that contain rubber latex having an unsaturated diene.

[0105] The aqueous component (D) having multiple phenolic hydroxy groups in its molecule is preferably lignin or a derivative thereof. Lignin, along with polysaccharides such as cellulose, is a major component of plant cell walls. Lignin contains functional groups such as hydroxyl groups, methoxy groups, carbonyl groups, and carboxyl groups. The phenolic hydroxy groups are particularly highly reactive, and therefore can be added to the aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures via an electron-withdrawing group such as a (meth)acrylate structure, a (meth)acrylamide structure, or a (meth)allyl structure, or can interact with an aqueous compound having a cationic substance such as the aqueous component (E) having multiple amino groups in its molecule.

[0106] Lignin is a polymer with a structure based on phenylpropane, but the molecular structure of lignin is diverse and it is a huge biopolymer that forms a three-dimensional network structure, so its molecular structure has not yet been fully elucidated.

[0107] Because natural lignin forms a strong composite material with polysaccharides such as cellulose in plant cell walls, it is considered extremely difficult to isolate natural lignin without denaturing its chemical structure. Various industrial separation methods are used to extract lignin from materials such as wood. Lignins obtained after separation include sulfonate lignin, kraft lignin, soda lignin, and steam-exploded lignin. Among these industrially handled lignins, lignins obtained on a large scale from the pulp waste liquor of chemical pulping in paper pulp manufacturing processes, i.e., lignosulfonates or kraft lignin, are well-known materials from the standpoints of availability and economy.

[0108] Examples of other lignins include lignins modified by hydroxymethylation, epoxidation, denitrification, acylation, or hydroxylation, diethanolamine-modified lignin, enzyme-modified lignin, laccase-modified lignin, urea-modified lignin, lignosulfonate, Alcel process lignin, alkali granite process lignin, polyethylene glycol-added lignin, and the like.

[0109] Kraft lignin is derived from a chemical pulping method (high-temperature, high-pressure reaction) called the kraft cooking method, which involves introducing wood chips, such as hardwood, softwood, miscellaneous wood, bamboo, kenaf, and bagasse, into a digester together with a cooking liquor containing sodium hydroxide, sodium sulfide, or the like. The kraft lignin is obtained by adding acid and / or carbon dioxide to the kraft waste liquor obtained after the kraft cooking process to precipitate the dissolved modified lignin, and then dehydrating and washing the resulting precipitate. The precipitate after dehydration and washing can be further purified by adding an organic solvent such as alcohol or acetone to dissolve the insoluble impurities, separating them, and drying, or by modifying the precipitate by introducing various functional groups as needed. Commercially available kraft lignin can be obtained. Among these, kraft lignin from Sigma-Aldrich Co., Ltd. Preferred examples of such reagents include those under the name "Lignin Alkali Craft" (CAS Number: 8068-05-1) manufactured by Biochem. LLC, and BioPiva 100 (CAS Number: 8068-05-1) or BioPiva 395 (CAS Number: 8068-05-1) manufactured by UPM Biochemicals.

[0110] The sulfonated lignins are lignin sulfonic acids and salts thereof obtained from waste liquor eluted from sulfite pulp during chemical pulping using a sulfite cooking method in which wood chips are reacted with a cooking liquor containing sulfite and / or a sulfite salt at high temperature and high pressure, and calcium lignin sulfonate, sodium lignin sulfonate, potassium lignin sulfonate, and magnesium lignin sulfonate are particularly preferred. Of these, sodium lignin sulfonate is preferred. These sulfonated lignins are commercially available, and examples of lignin sulfonates or modified lignin sulfonates include the Sunex series manufactured by Nippon Paper Industries Co., Ltd.

[0111] Examples of high-value-added lignin sulfonates include not only high-purity products but also partially desulfonated (low-) lignin sulfonates, which have a reduced degree of sulfonation, obtained by heating lignin sulfonates in an alkaline aqueous solution using sodium hydroxide or ammonia in the presence of an oxidizing agent such as oxygen (see, for example, JP 2016-135834 A). Examples of high-purity lignin sulfonates or modified lignin sulfonates include the Pearlex series manufactured by Nippon Paper Industries Co., Ltd., and examples of partially desulfonated lignin sulfonates include the Vanilex series manufactured by Nippon Paper Industries Co., Ltd. Among these, a partially desulfonated (low-) sulfonated lignin sulfonate with a reduced degree of sulfonation, manufactured by Tokyo Chemical Industry Co., Ltd., under the reagent name "Lignin (Alkali)" (CAS Number: 8061-51-6, solid powder), is preferred. The aqueous component (D) having multiple phenolic hydroxy groups in its molecule is preferably a derivative of lignin sulfonic acid. When the aqueous component (D) having multiple phenolic hydroxy groups in the molecule is a derivative of lignosulfonic acid, when the adhesive composition is used on organic fibers, the adhesion between the organic fibers and the coating rubber composition is particularly good. In this specification, the term "derivative of lignosulfonic acid" includes lignosulfonates, modified lignosulfonates, partially desulfonated lignosulfonic acids, partially (low) desulfonated lignosulfonates, etc.

[0112] The lignosulfonic acid can be preferably used if it is a partially desulfonated lignosulfonic acid, since it has good dispersibility on the surface of organic fibers when the organic fibers are fixed (see JP-A-2002-146028).

[0113] Tannins are a group of polyphenols found in a wide range of plants, including woody trees, as well as fruits, leaves, and seeds, such as grapes, persimmons, berries, cloves, legumes, medicinal herbs, tea leaves, and cocoa beans. Tannin molecules generally contain numerous hydroxyl groups, and often also carboxyl groups, and tend to form strong complexes and conjugates with a wide range of macromolecules.

[0114] The tannins include tannic acid, proanthocyanidins, flavonoids, gallic acid esters, catechins, etc., as well as their salts and derivatives such as modified forms. Flavonoids are ubiquitous in the leaves, stems, and bark of plants and are generally called tannins, which consist of hydrolyzable tannins and condensed tannins. These tannins can be distinguished by boiling them in dilute hydrochloric acid; condensed tannins form insoluble precipitates, while hydrolyzable tannins are hydrolyzed to produce water-soluble substances.

[0115] Both hydrolyzable tannins and condensed tannins are water-soluble and can be obtained by extraction from plant materials such as wood, bark, leaves, fruits, pods, and insect larvae using hot water extraction or other methods. Hydrolyzable tannins can be obtained, for example, from the wood of chestnuts and nuts, oak bark, tea leaves, and the insect larvae of Chinese gallnuts and gallnuts, while condensed tannins can be obtained from the wood of quebracho trees, mimosa bark, persimmons, buckwheat seeds, etc. Particularly preferred as a condensed tannin is "Mimosa" (solid powder), a product name obtained from mimosa bark, manufactured by Kawamura Tsusho Co., Ltd.

[0116] The content (solids content) of the aqueous component (D) having multiple phenolic hydroxy groups in the molecule relative to the total solids content of the adhesive composition is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. The content of the aqueous component (D) having multiple phenolic hydroxy groups in the molecule is preferably 60% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. When the content of the aqueous component (D) having multiple phenolic hydroxy groups in the molecule is 1% by mass or more, the adhesion between the organic fiber and the coating rubber composition is improved. When the content of the aqueous component (D) having multiple phenolic hydroxy groups in the molecule is 60% by mass or less, the amount of other components, such as rubber latex, blended into the adhesive composition can be kept at a certain level, resulting in better adhesion to the rubber substrate.

[0117] <(E) Aqueous Component Having Multiple Amino Groups in the Molecule> A preferred embodiment of the adhesive composition of the present invention comprises (A) a rubber latex having an unsaturated diene, (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule, and (E) an aqueous component having multiple amino groups in the molecule. Note that the aqueous component (E) having multiple amino groups in the molecule of the present invention is not particularly limited as long as there are multiple amino groups in one molecule, and may have two, three, or more amino groups.

[0118] The (E) aqueous component having multiple amino groups in its molecule is preferably a polyfunctional amine compound having two or more primary, secondary, or tertiary amino groups. When the (E) aqueous component having multiple amino groups in its molecule is a polyfunctional amine compound having two or more primary, secondary, or tertiary amino groups, the adhesive composition can improve the adhesion between the organic fiber and the coating rubber composition when used with the organic fiber. Examples of the (E) aqueous component having multiple amino groups in its molecule include ethylenediamine, propylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, phenylenediamine, metaxylenediamine, diethylenetriamine, triethylenetetramine, and triaminopropane, as well as amino-group-containing resins having amino groups, such as polyvinylamine, polyethyleneimine, polyallylamine, polyetheramine, and polylysine.

[0119] The number average molecular weight of the amino group-containing resin is, for example, 100 to 1,000,000, preferably 200 to 10,000, and more preferably 300 to 5,000. The number average molecular weight of the amino group-containing resin is determined, for example, by a known viscosity method. If the molecular weight of the amino group-containing resin is too large, the viscosity may become too high due to gel crosslinking in the adhesive composition liquid, which may cause problems in workability.

[0120] The aqueous component (E) having multiple amino groups in its molecule coats the surface of the rubber latex (A) having an unsaturated diene in the adhesive composition, thereby suppressing tackiness. The surface-adsorbing function of the component (E) coats the surface of the rubber latex (A) having an unsaturated diene, forming a composite with the rubber latex (A) having an unsaturated diene. This coating can suppress the tackiness of the rubber latex (A) having an unsaturated diene, and has the effect of improving the shelf life (pot life) and mechanical stability of the adhesive composition. Furthermore, coating the adhesive composition on an organic fiber cord also has the effect of improving the heat-resistant adhesive strength between the rubber and the organic fiber cord.

[0121] The aqueous component (E) having multiple amino groups in the molecule is preferably (E-1) a polypeptide having amino groups, (E-2) a polyetheramine, (E-3) a polyethyleneimine, or (E-4) a polyamidoamine. When the aqueous component (E) having multiple amino groups in the molecule is (E-1) a polypeptide having amino groups, (E-2) a polyetheramine, (E-3) a polyethyleneimine, or (E-4) a polyamidoamine, the adhesive composition used on organic fibers provides better adhesion between the organic fibers and the coating rubber composition.

[0122] In the adhesive composition of the present invention, the content of the (E) aqueous component having multiple amino groups in the molecule is not particularly limited, but is preferably 0.05% by mass or more and 20% by mass or less. The content of the (E) aqueous component having multiple amino groups in the molecule is more preferably 0.2% by mass or more and 15% by mass or less, and particularly preferably 0.5% by mass or more and 12% by mass or less. When the content of the (E) aqueous component having multiple amino groups in the molecule is 0.05% by mass or more, the adhesion between the organic fiber and the coating rubber composition is improved. Furthermore, when the content of the (E) aqueous component having multiple amino groups in the molecule is 20% by mass or less, it is possible to ensure a certain amount or more of other components, such as rubber latex, blended into the adhesive composition, resulting in better adhesion to the rubber substrate.

[0123] --(E-1) Polypeptide Having an Amino Group--Specific examples of the (E-1) polypeptide having an amino group include animal-derived proteins such as polylysine, wool, milk, silk (silk fibroin), fish scales, and skin (pigskin, etc.), plant-derived proteins such as beans (soybeans, almonds, etc.), denatured proteins such as acid casein, and hydrolyzed polypeptides obtained by hydrolyzing these proteins. The (E-1) polypeptide having multiple amino groups in the molecule is not particularly limited in the present invention, but polylysine was used in the examples described below. When the (E) aqueous component having multiple amino groups in the molecule is polylysine, the adhesive composition used on organic fibers further improves the adhesion between the organic fibers and the coating rubber composition.

[0124] The polylysine is a polyamino acid in which L-lysine, an essential amino acid, is polymerized in a linear chain, and examples thereof include α-polylysine produced by chemical synthesis and ε-polylysine produced by fermentation. ε-poly-L-lysine is a water-soluble polyamino acid in which the amino group at the ε-position of L-lysine is peptide-bonded to a carboxyl group, resulting in a linear chain. It is an excellent cationic polymer with biodegradability, produced by bacterial fermentation, etc., and is used as a natural food preservative. Polylysine is represented by the following structural formula (2): In the above formula, n represents the degree of polymerization of lysine.

[0125] The degree of polymerization n of the polylysine is preferably 25 to 35. The weight-average molecular weight of the polylysine is preferably 3,000 or more, more preferably 4,000 or more, and preferably 10,000 or less, more preferably 8,000 or less, even more preferably 6,000 or less, particularly preferably 5,000 or less.

[0126] --(E-2) Polyetheramine-- The (E-2) polyetheramine is a polyetheramine containing at least one primary and / or secondary amine functional group bonded to the polyether backbone, or a modified product of such a compound. Useful polyetheramines include polyetheramines in which an amine functional group is introduced at the end of a polyether polymer. Examples of the (E-2) polyetheramine include polyether monoamines, polyether diamines, polyether triamines, and polyether polyamines.

[0127] The polyetheramine (E-2) is preferably a compound containing a polyether skeletal structure and an amine functional group, where "a polyether skeletal structure" refers to a hydrocarbon chain incorporating an oxygen atom of an ether bond. Generally, as long as the effects of the present invention are not significantly impaired, polyether polymers obtained by ring-opening polymerization of cyclic monomers such as polyalkylene oxides or polyalkyleneimines, or polyethers such as naturally occurring molecules, may be included. For example, polyethers obtained by ring-opening polymerization of the cyclic monomers include polyether polymers such as polyethylene oxide obtained by ring-opening polymerization of ethylene oxide, polypropylene oxide obtained by ring-opening polymerization of propylene oxide, and polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran. Polyether polymers obtained by ring-opening polymerization of cyclic polyalkylene oxides contain oxyalkylene units -R in the molecular chain of the polymer. １ -O-(R １ is a linear or branched alkylene group having 1 to 14 carbon atoms), and examples of the repeating oxyalkylene units include -CH ２ O-, -CH ２ CH ２ O— (i.e., oxyethylene unit), —CH ２ CH (CH ３ ) O— (i.e., oxypropylene unit), —CH ２ CH(C ２ H ５ ) O—, —CH ２ C(CH３ ) ２ O-, -CH ２ CH ２ CH ２ CH ２ The repeating oxyalkylene units of this polyether polymer may be composed of only one type of repeating unit, or may be composed of two or more types of units.

[0128] When the polyether skeletal structure of the polyether (E-2) is a "polyether polymer obtained by polymerizing a polyalkylene oxide," the polyether amine (E-2) is easily soluble or dispersible in water. Therefore, the molecular chain of the polyether polymer preferably contains a hydrophilic alkylene oxide unit, specifically, a structure containing an oxyethylene unit, an oxypropylene unit, or a combination of an oxyethylene unit and an oxypropylene unit is preferred. When the molecular chain of such a polyether has an HLB value, as determined by the Griffin method, within the range of 8 to 20, the polyether amine (E-2) is particularly preferred because it is easily soluble in water.

[0129] In the present invention, the polyether polymer obtained by ring-opening polymerization of the cyclic monomer also includes dimers, trimers, and oligomers, but preferably has a weight average molecular weight Mw of 200 to 200,000 as measured by GPC and converted using a polystyrene calibration curve. The lower limit of the weight average molecular weight Mw is more preferably 300, and even more preferably 500. The upper limit of the weight average molecular weight Mw is more preferably 100,000, even more preferably 10,000, and particularly preferably 3,000.

[0130] In one embodiment, the (E-2) polyetheramine is preferably a polyetheramine selected from the group consisting of polyethermonoamines, polyetherdiamines, polyethertriamines, polyfunctionalized polyetheramines, and mixtures thereof.

[0131] The commercially available polyether monoamine is not particularly limited, but examples of polyether monoamines include JEFFAMINE (registered trademark) M-600, M-1000, M-2005, M-2070, M-2095, and M-3085 manufactured by Huntsman Petrochemical LLC, and Genamin (registered trademark) M41 / 2000 manufactured by CLARIANT AG.

[0132] Examples of polyether diamines include JEFFAMINE (registered trademark) D-230, D-400, D-2000, D-2010, D-4000, ED-600, ED-900, ED-2003, EDR-148, THR-100, and THR-170 manufactured by Huntsman Petrochemical LLC, and secondary diamine SD-2001; Baxxodur (registered trademark) EC-130, EC-280, EC-301, EC-302, and EC-303 manufactured by BASF SE; Genamin (registered trademark) D01 / 2000 manufactured by CLARIANT AG; , Ltd. D-230, D-400, D-2000, ED-600, ED-900, ED-2003, Yantai Dasteck Chemicals Co. , Ltd. D-400, D-2000, WUXI ACRYL TECHNOLOGY CO. , MA-223, MA-240, MA-2200 manufactured by Yantai Minsheng Chemicals Co., Ltd. , Ltd. AMD-230, AMD-400, AMD-1000, AMD-2000, IRO COATING ADDITIVE CO., LTD. , LTD. Examples of such a filter include D-230, D-400, and D-2000 manufactured by the company.

[0133] Examples of polyether triamines include JEFFAMINE (registered trademark) T-403, T-3000, and T-5000 manufactured by Huntsman Petrochemical LLC, Baxxodur (registered trademark) EC-311 and EC-5000 manufactured by BASF SE, Genamin (registered trademark) T01 / 5000 manufactured by CLARIANT AG, T-403 and T-3000 manufactured by Yangzhou Chehua New Materials Co., Ltd., T-403 manufactured by Yantai Dasteck Chemicals Co., Ltd., and T-5000 manufactured by WUXI ACRYL TECHNOLOGY CO., LTD. Examples of suitable polyetheramines include MA-340 and MA-3500 manufactured by Yantai Minsheng Chemicals Co., Ltd., AMT-403 and AMT-5000 manufactured by Yantai Minsheng Chemicals Co., Ltd., and T-403, T-3000, and T-5000 manufactured by IRO COATING ADDITIVE CO., LTD. In the examples described below, Baxxodur EC301, a polyoxypropylene diamine manufactured by BASF SE, was used as the polyetheramine (E-2).

[0134] --(E-3) Polyethyleneimine-- In the present invention, the above-mentioned (E-3) polyethyleneimine can be suitably used as the aqueous component (E) having a plurality of amino groups in the molecule. Polyethyleneimine is a water-soluble polymer obtained by polymerizing ethyleneimine, and is a polymer of amine and ethylene (CH ２ CH ２ ) repeating units. Polyethyleneimine generally contains primary, secondary, and tertiary amino groups, and for example, polyethyleneimine having a branched structure rather than a completely linear molecule, and having an average molecular weight of about 600 as a commercially available reagent, can be used. The polyethyleneimine (E-3) is available in liquid form, but when used in the adhesive composition of the present invention, it is preferably used as an aqueous solution.

[0135] --(E-4) Polyamidoamine-- Examples of the (E-4) polyamidoamine include reaction products of polyamines with long-chain carboxylic acids (polycarboxylic acids). Examples of polyamines include ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tripropylenetetramine, tetraethylenepentamine, hexamethylenediamine, iminobispropylamine, bis(hexamethylene)triamine, 1,3,6-trisaminomethylhexane, trimethylhexamethylenediamine, polyetherdiamine, diethylaminopropylamine, 1,4-cyclohexanediamine, isophoronediamine, bis(aminomethyl)norbornane, bis(4-aminocyclohexyl)methane, N-aminoethylpiperazine, diaminodicyclohexylmethane, bisaminomethylcyclohexane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro(5.5)undecane, and norbornenediamine. Examples of long-chain carboxylic acids (polycarboxylic acids) include dimer acids (polymers of unsaturated fatty acids).

[0136] <(F) Compound Containing an Amide Bond Structure> One preferred embodiment of the adhesive composition of the present invention comprises (A) a rubber latex having an unsaturated diene, (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures or (meth)allyl structures in the molecule, and (F) a compound containing an amide bond structure.

[0137] By using a compound containing an amide bond (F) in the adhesive composition together with the rubber latex containing an unsaturated diene (A), the compound containing an amide bond (F) covers the surface of the rubber latex particles, preventing the rubber latex particles from aggregating. As a result, the dispersibility of the rubber latex when subjected to mechanical load is improved, achieving excellent mechanical stability. As a result, the adhesive composition containing the compound containing an amide bond (F) can prevent the adhesive composition from adhering to rolls or the like during the process of coating an organic fiber cord with the adhesive composition for organic fiber cords, drying, and thermal curing, thereby improving workability. Furthermore, the compound containing an amide bond (F) is fixed to the surface of the rubber latex containing an unsaturated diene (A), thereby improving the adhesion between the adhesive composition and the rubber composition to be adhered.

[0138] Furthermore, as described above, by incorporating an aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule, the compound (F) having an amide bond structure has affinity with the aqueous compound (B) having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule due to similarities in some structures, and the compound (F) having an amide bond structure and the wetted component (B) crosslink to form a mutual wetting network, which increases the interaction between the components and improves the adhesion between the adhesive composition and the rubber composition to be adhered.

[0139] The compound (F) containing an amide bond structure is preferably a polymer of (meth)acrylamide or a copolymer containing (meth)acrylamide and another polymerizable monomer, and may, for example, contain a structure consisting of (a) (meth)acrylamide and / or (b) a copolymer of a vinyl monomer having a cationic group, and / or (c) a vinyl monomer having an anionic group, and / or (d) a copolymer of other copolymerizable polymerizable monomers. When the compound (F) containing an amide bond structure is a polymer of (meth)acrylamide or a copolymer containing (meth)acrylamide and another polymerizable monomer, the adhesive composition used on organic fibers provides better adhesion between the organic fibers and the coating rubber composition.

[0140] Here, the (a) (meth)acrylamide refers to acrylamide and methacrylamide. In the following, (meth)acryl is considered to be synonymous with acrylic and / or methacrylic, and will be abbreviated in the same manner. The "amide bond structure" can be obtained mainly from a structure formed by polymerizing the (a) (meth)acrylamide. The (meth)acrylamides can be used alone or in combination of two types. Preferably, acrylamide is used alone from the standpoint of economy.

[0141] The content of the (meth)acrylamide (a) relative to the total monomers constituting the acrylamide polymer is, for example, 50 mol % or more, preferably 60 mol % or more, and preferably 100 mol % or less. If the content of the (meth)acrylamide (a) component is less than 50 mol %, the adhesive strength due to the cohesive force of hydrogen bonding or the like caused by the amide moiety will be reduced.

[0142] Examples of the vinyl monomer having a cationic group (b) include vinyl monomers having a primary amino group, a secondary amino group, a tertiary amino group, or a quaternary ammonium salt.

[0143] Examples of the vinyl monomer having a primary amino group include 2-propenylamine and 2-methyl-2-propenylamine; inorganic acid salts such as hydrochlorides and sulfates of the primary amino monomers; and organic acid salts such as formates and acetates of the primary amino monomers.

[0144] Examples of the vinyl monomer having a secondary amino group include di(2-propenyl)amine (diallylamine), di(2-methyl-2-propenyl)amine; or inorganic acid salts such as hydrochlorides and sulfates of the secondary amino monomers; or organic acid salts such as formates and acetates of the secondary amino monomers.

[0145] Examples of the vinyl monomer having a tertiary amino group include dialkylaminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylate; dialkylaminoalkyl (meth)acrylamides such as N,N-dimethylaminoethyl (meth)acrylamide, N,N-diethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, and N,N-diethylaminopropyl (meth)acrylamide; tertiary amine monomers such as allylamine, diallylamine, and vinylpyridine; inorganic acid salts such as hydrochlorides and sulfates of the above-mentioned tertiary amino monomers; and organic acid salts such as formates and acetates of the above-mentioned tertiary amino monomers. Among these, N,N-dimethylaminoethyl (meth)acrylate is preferred in terms of polymerizability and cost.

[0146] The vinyl monomer having a quaternary ammonium salt is a cationic copolymerizable monomer having a quaternary ammonium group and an ethylenic double bond, and examples thereof include a vinyl monomer of a quaternary ammonium salt (quaternary amino monomer) obtained by reacting the vinyl monomer having a tertiary amino group with an alkylating agent, and a quaternary amino monomer obtained by quaternizing the tertiary amino group of a diallylamine derivative monomer, etc. These quaternary ammonium monomers can be used alone or in combination of two or more.

[0147] Examples of the quaternized tertiary amino monomer include alkylating agents that quaternize the tertiary amino group of the polymerizable monomer having a tertiary amino group, such as alkyl halides such as methyl chloride (methyl chloride) and methyl bromide; aralkyl halides such as benzyl chloride (benzyl chloride); dimethyl sulfate, diethyl sulfate, epichlorohydrin, glycidyl trialkyl ammonium chloride, and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride. Among these quaternized tertiary amino monomers, preferred are quaternized dialkylaminoalkyl (meth)acrylamides. Preferred quaternizing alkylating agents include quaternized methyl chloride or benzyl chloride.

[0148] Examples of the quaternary products of the diallylamine derivative monomer include diallyldimethylammonium chloride, diallyldimethylammonium bromide, diallyldiethylammonium chloride, diallyldibutylammonium chloride, diallylmethylethylammonium chloride, etc. Of these quaternary products of the diallylamine derivative monomer, diallyldimethylammonium chloride is preferred.

[0149] In the present invention, vinyl monomers having these primary amino groups, secondary amino groups, tertiary amino groups or quaternary ammonium salts can be used alone or in combination of two or more. Note that while primary to tertiary amino groups are prevented from dissociating at pH 7 or higher, when a quaternary ammonium salt group is contained, dissociation is possible even at pH 9 or higher. Therefore, when mixed with a latex generally having a pH of 10 or higher, the function as a cation can be maintained over a wide range of pH. However, primary amine groups have a stronger hydrogen bonding strength than tertiary and quaternary amines, and therefore can enhance interaction with other components of the adhesive composition.

[0150] The content of the (b) vinyl monomer having a cationic group is not particularly limited, but when included, it is, for example, 0.01 mol% or more, preferably 0.5 mol% or more, and for example, 20 mol% or less, preferably 10 mol% or less, based on the total monomers constituting the acrylamide-based polymer. When the content of the vinyl monomer having a cationic group is 0.01 mol% or more, the latex particles dispersed in water with an anionic surfactant are adsorbed by coacervation to form a surface coating, thereby suppressing the stickiness of the latex. A content of 0.5 mol% or more is preferred. A content of 20 mol% or less is undesirable because it increases the cohesion between particles. A content of 10 mol% or less of the vinyl monomer having a cationic group is preferred because it tends to prevent the degree of polymerization from becoming short during production.

[0151] The (c) vinyl monomer having an anionic group is not particularly limited as long as it is a vinyl monomer having an anionic group in the molecule, and examples thereof include unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, unsaturated tricarboxylic acids, unsaturated tetracarboxylic acids, and salts thereof. Specific examples include unsaturated monocarboxylic acids such as (meth)acrylic acid, angelic acid, tiglic acid, crotonic acid, and isocrotonic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, aconitic acid, mesaconic acid, muconic acid, and citraconic acid; unsaturated tricarboxylic acids such as 3-butene-1,2,3-tricarboxylic acid, 4-pentene-1,2,4-tricarboxylic acid, and aconitic acid; alkali metal salts such as sodium salts and potassium salts or ammonium salts of these various organic acids; sulfonic acid monomers having a vinyl group such as vinyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, (meth)allylsulfonic acid, and diacryloylimide; and alkali metal salts such as sodium salts and potassium salts or ammonium salts of these various organic acids. In the present invention, these vinyl monomers having an anionic carboxyl group and their salts can be used alone or in combination of two or more. Among these, in terms of polymerizability and cost, unsaturated monocarboxylic acids and unsaturated dicarboxylic acids, specifically acrylic acid, 2-acrylamido-N-glycolic acid, itaconic acid and salts thereof are preferred, and acrylic acid or its sodium salt is particularly preferred.

[0152] The content of the (c) vinyl monomer having an anionic group is not particularly limited, but when it is included, it is, for example, 0.01 mol% or more, preferably 0.5 mol% or more, and for example, 20 mol% or less, preferably 10 mol% or less, based on the total monomers constituting the acrylamide-based polymer. When the polymerization components contain 0.01 mol% or more of anionic polymerizable monomer, the polyamide adsorbed to the latex has dispersibility due to the anionic group, and the adhesiveness suppression effect is enhanced. On the other hand, if the number of carboxyl groups increases, the acidity becomes stronger during rubber vulcanization, and here, the sulfur crosslinking reaction of the rubber latex is slowed when the acidity is strong, so the crosslinking of the adhesive layer tends to be reduced.

[0153] In addition, the compound (F) containing an amide bond structure may be a copolymer containing other copolymerizable monomers (d) from the viewpoint of processability.

[0154] Specific examples of other polymerizable monomers include N-substituted lower alkylacrylamides other than (meth)acrylamides, such as N-ethylacrylamide, N,N-dimethylacrylamide, and N-isopropylacrylamide; N,N-dialkyl(meth)acrylamides, such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, and N,N-diisopropyl(meth)acrylamide; alkylenebis(meth)acrylamides, such as methylenebis(meth)acrylamide and ethylenebis(meth)acrylamide; allyl(meth)acrylamide; and N-substituted acrylamide monomers, such as N,N'-dimethylacrylamide, diacetoneacrylamide, and isopropylacrylamide. Examples of other copolymerizable polymerizable monomers containing an imide group include diacryloyl imide. Preferred examples include alkyl(meth)acrylates and hydroxyalkyl(meth)acrylates.

[0155] In addition, other copolymerizable polymerizable monomers that do not contain an amide group or an imide group include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate; hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate; (meth)acrylates having a hydroxyl group such as glycerol mono(meth)acrylate; polyalkylene glycol mono(meth)acrylates such as diethylene glycol (meth)acrylate and methoxypolyethylene glycol (meth)acrylate; ethylene glycol nitrile compound monomers such as acryloylmorpholine and (meth)acrylonitrile; olefins such as vinyl acetate, vinyl chloride, vinylidene chloride, ethylene, propylene, and butene; substituted vinyl acetates such as isopropenyl acetate and 1-methoxyvinyl acetate; and aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, vinylpyrrolidone, and vinyloxazoline.

[0156] These other polymerizable monomers may be used alone or in combination of two or more. Among them, it is preferable to use crosslinkable monomers containing an amide group such as N-substituted acrylamide monomers such as methylene bis(meth)acrylamide, ethylene bis(meth)acrylamide, allyl (meth)acrylamide, N,N'-dimethylacrylamide, diacetone acrylamide, and isopropyl acrylamide; crosslinkable monomers containing an imide group such as diacryloyl imide; nitrogen-free bifunctional crosslinkable monomers such as divinylbenzene, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and allyl (meth)acrylate; and nitrogen-free polyfunctional crosslinkable monomers such as pentaerythritol triacrylate, trimethylolpropane acrylate, and tetraallyloxyethane, because when a branched structure is introduced by the elongation reaction during polymerization, the cured film after heat treatment of the adhesive composition has high hardness and excellent adhesion to the substrate. Of these, N,N-dialkyl(meth)acrylamides and alkylenebis(meth)acrylamides are preferred, and N,N-dimethylacrylamide and methylenebis(meth)acrylamide are more preferred.

[0157] (d) Other monomers used in the copolymer containing other copolymerizable polymerizable monomers are not limited to the monomers exemplified above. These are optional components, and their amount is not particularly limited, but is generally 0.01 mol % or more, preferably 0.1 mol % to 40 mol %. For example, 0.01 mol % or more, preferably 0.1 mol % or more, and for example, 30 mol % or less, preferably 20 mol % or less.

[0158] The (F) compound having an amide bond structure may be further modified, and includes modified products crosslinked by adding a hydrazide compound such as hydrazine, modified products obtained by Mannich modification of polyacrylamide in which part of the acrylamide structure derived from (a) (meth)acrylamide is modified to a cationic group, and modified products of cationic polyacrylamides such as glyoxalated polyacrylamide with a formaldehyde-based crosslinking agent such as glyoxal.

[0159] Specifically, with regard to the compound (F) containing an amide bond structure, a polymer made of (a) (meth)acrylamide is also called nonionic polyacrylamide, a copolymer made of (a) (meth)acrylamide and (b) a vinyl monomer having a cationic group is also called cationic polyacrylamide, a compound made of a copolymer of (a) (meth)acrylamide and (c) a vinyl monomer having an anionic group is also called anionic polyacrylamide, and a copolymer of a polymer made of (a) (meth)acrylamide and (b) a vinyl monomer having a cationic group and (c) a vinyl monomer having an anionic group is also called amphoteric polyacrylamide.

[0160] These (F) compounds containing an amide bond structure can be obtained by reacting nonionic polyacrylamide, cationic polyacrylamide, anionic polyacrylamide containing a carboxyl group, or amphoteric polyacrylamide using known methods. For example, the production method is not particularly limited, and they can be obtained by copolymerizing a mixture of (meth)acrylamide and a cationic vinyl monomer and / or an ionic vinyl monomer by aqueous solution polymerization, emulsion polymerization using water and an organic solvent, suspension polymerization, or the like. They can also be produced by various conventional methods such as simultaneous polymerization and continuous drop polymerization. For example, a copolymer can be produced by charging the monomer mixture and water, adding a known radical polymerization initiator such as a persulfate salt (e.g., potassium persulfate, ammonium persulfate) or a redox polymerization initiator, and optionally adding a chain transfer agent, at approximately 15°C to 100°C for 0.1 to several hours with stirring. The polymerization reaction can also be terminated by adding a known polymerization terminator (e.g., sodium thiosulfate, sodium sulfite, etc.).

[0161] Examples of chain transfer agents include isopropyl alcohol and mercapto compounds (e.g., mercaptoethanol, thiourea, thioglycolic acid, mercaptopropionic acid, thiosalicylic acid, thiolactic acid, aminoethanethiol, thioglycerol, thiomalic acid, etc.), etc. The amount of such a chain transfer agent used is usually 0.01 to 5 parts by mass, and preferably 0.1 to 3 parts by mass, per 100 parts by mass of the total monomer weight of the compound containing an acrylamide structure having a cationic group and / or a carboxyl group.

[0162] The compound (F) containing an amide bond structure obtained in this manner can be obtained in the form of a product such as an aqueous solution or aqueous dispersion. Polyacrylamide obtained in the form of a gel may be mechanically pulverized and then re-dispersed in water for use. When used in the adhesive composition of the present invention, it is preferably used as an aqueous solution.

[0163] The weight-average molecular weight of the copolymerized polyacrylamide obtained in this manner is, for example, 1 million or more, preferably 2 million or more, and more preferably 2 million or more, and for example, 15 million or less, preferably 10 million or less, and more preferably 8 million or less. When the weight-average molecular weight of the acrylamide-containing compound is 1 million or more, aggregation of the rubber latex particles can be more reliably suppressed, and when the weight-average molecular weight of the acrylamide-containing compound is 15 million or less, problems such as crosslinking of the acrylamide-containing compound to form gels do not occur.

[0164] Furthermore, if the pH is generally about 3 to 9 and the viscosity is about 100 to 10,000 mPa·s in a 10% by mass aqueous solution, storage and transfer in a liquid state and use in liquid form become easy.

[0165] As the compound (F) containing an amide bond structure, commercially available nonionic, anionic, cationic, or amphoteric polyacrylamide products can be used. In particular, papermaking chemicals such as internal additives for paper, such as retention aids, drainage aids, and paper strength agents, can be used.

[0166] Copolymerized polyacrylamide, a papermaking agent, can strengthen the paper product by adsorbing (fixing) to pulp. Addition of a paper strength enhancer improves the adhesive strength between the cellulose fibers that make up paper during papermaking (Takahata, Yasushi, Use of Synthetic Polymers in the Papermaking Industry (1), Journal of the Paper and Pulp Technology Association, Vol. 27, No. 12, p. 607, 1973). The amide groups of polyacrylamide resins are highly reactive and have a strong affinity with fillers due to hydrogen bonds, van der Waals forces, etc., resulting in excellent cohesive strength. Therefore, the amide moiety is a moiety that improves paper strength. (a) A compound containing an amide bond structure such as (meth)acrylamide is preferred in the adhesive composition of the present invention, as it improves the cohesive failure resistance of the adhesive layer between the adhered fiber filaments.

[0167] Incidentally, even in the case of nonionic polyacrylamides made of (a) (meth)acrylamide, some of the amide bond structures are decomposed to have anionic and cationic groups, so that they are not completely nonionic but have slight amphoteric properties. These nonionic polyacrylamides are inexpensive and have fixing properties due to their slight amphoteric properties, which makes them preferable. Amphoteric polyacrylamides have the function of fixing to the rubber latex and the function of fixing to the substrate, and even if added in excess, they have the function of fixing by themselves even if the cationic groups become excessive, so that they are less likely to thicken the liquid and can be used favorably.

[0168] The content (solid content) of the (F) compound containing an amide bond structure relative to the total solid content of the adhesive composition is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.4% by mass or more. The content of the (F) compound containing an amide bond structure is preferably 25% by mass or less, more preferably 15% by mass or less, and even more preferably 8% by mass or less. When the content of the (F) compound containing an amide bond structure is 0.1% by mass or more, the adhesion between the organic fiber and the coating rubber composition is improved. When the content of the (F) compound containing an amide bond structure is 25% by mass or less, it is 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 substrate.

[0169] <(C) Aqueous Compound Having a (Thermally Dissociable Blocked) Isocyanate Group> A preferred embodiment of the adhesive composition of the present invention comprises (A) a rubber latex having an unsaturated diene, (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures or (meth)allyl structures in the molecule, and (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group, and further comprises one or more compounds selected from the group consisting of the following (D) to (F): (D) an aqueous component having a plurality of phenolic hydroxy groups in the molecule, (E) an aqueous component having a plurality of amino groups in the molecule, and (F) a compound containing an amide bond structure.

[0170] The adhesive composition of the preferred embodiment contains the aqueous compound (C) having a (thermally dissociable blocked) isocyanate group, and thus can achieve excellent adhesion and mechanical stability even when the adhesive composition does not contain formaldehyde or resorcinol.

[0171] The (thermally dissociable blocked) isocyanate group of the (C) aqueous compound having a (thermally dissociable blocked) isocyanate group means a thermally dissociable blocked isocyanate group or an isocyanate group. Specifically, the (thermally dissociable blocked) isocyanate group includes (i) a thermally dissociable blocked isocyanate group formed by reaction of an isocyanate group with a thermally dissociable blocking agent for the isocyanate group, (ii) an isocyanate group that has not reacted with the thermally dissociable blocking agent for the isocyanate group, (iii) an isocyanate group formed by dissociation of a thermally dissociable blocking agent from a thermally dissociable blocked isocyanate group, and (iv) an isocyanate group.

[0172] The term "aqueous" in the aqueous compound (C) having a (thermally dissociable blocked) isocyanate group refers to water-soluble or water-dispersible. Furthermore, the term "water-soluble" does not necessarily mean complete water-solubility, but may also mean partial water-solubility or no phase separation in the aqueous solution of the adhesive composition.

[0173] The aqueous compound (C) having a (thermally dissociable, blocked) isocyanate group is preferably a water-dispersible (thermally dissociable, blocked) isocyanate compound (C-1) consisting of an addition product of a polyisocyanate having an aromatic ring and a blocking agent having one or more active hydrogen groups (hereinafter also referred to simply as "component (C-1)"). In this case, when the adhesive composition is used on organic fibers, the adhesion between the organic fibers and the coating rubber composition becomes better.

[0174] Here, with regard to the component (C-1), 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.

[0175] 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, in the step shown in Fig. 1, the temperature of the heat treatment for thermal curing after the adhesive treatment liquid is applied and dried 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.

[0176] Examples of the blocking agent include, but are not limited to, alcohols, phenols, active methylenes, oximes, lactams, amines, etc., and specifically include lactams such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, etc.; phenols such as phenol, cresol, ethylphenol, butylphenol, octylphenol, nonylphenol, dinonylphenol, thiophenol, chlorophenol, amylphenol, etc.; oximes such as methyl ethyl ketoxime, acetoxime, acetophenone oxime, benzophenone oxime, cyclohexanone oxime, etc.; alcohols such as methanol, ethanol, butanol, isopropyl alcohol, butyl alcohol, cyclohexanol, etc.; malonic acid dialkyl esters such as dimethyl malonate, diethyl malonate, etc.; active methylenes such as methyl acetoacetate, ethyl acetoacetate, acetylacetone, etc.; mercaptans such as butyl mercaptan, dodecyl mercaptan, etc. 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. Among these blocking agents, phenol, ε-caprolactam, and ketoxime can be preferably used, as they are easily thermally dissociated by heating to stably achieve thermal curing of the adhesive composition.

[0177] The component (C-1) specifically includes aromatic polyisocyanates or aromatic aliphatic polyisocyanates, and examples of the 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, 4,4'-diphenylmethane diisocyanate (MDI); dialkyl Examples of the aromatic polyisocyanates include diphenylmethane diisocyanates such as diphenylmethane 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; naphthalene diisocyanates such as 1,5-naphthylene diisocyanate; etc. Examples of the 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 carbodiimides, polyols, and allophanates. Of these polyisocyanates containing an aromatic ring in the molecule, aromatic isocyanates are preferred from the viewpoint of the cord bundling properties of the adhesive composition, more preferably tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), or polymethylene polyphenyl polyisocyanate (polymeric MDI), and particularly preferably diphenylmethane diisocyanates (MDIs). By using a blocked methylene diphenyl isocyanate, particularly a blocked methylene diphenyl diisocyanate (also referred to as "diphenylmethane diisocyanate"), as component (C-1), the adhesion between the organic fiber and the coating rubber composition is further improved when the adhesive composition is used on organic fiber.

[0178] Furthermore, it is more preferable that 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) (hereinafter also referred to simply as "component (C-2)"). In this case, when the adhesive composition is used on organic fibers, the adhesion between the organic fibers and the coating rubber composition becomes better. Details of the component (C-2) will be described later for convenience of explanation.

[0179] The content (solids content) of the aqueous compound having a (thermally dissociable blocked) isocyanate group (C) relative to the total solids content of the adhesive composition is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 18% by mass or more. The content of the aqueous compound having a (thermally dissociable blocked) isocyanate group (C) is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 45% by mass or less. When the content of the aqueous compound having a (thermally dissociable blocked) isocyanate group (C) is 5% by mass or more, the adhesion between the organic fiber and the coating rubber composition is improved. When the content of the aqueous compound having a (thermally dissociable blocked) isocyanate group (C) is 70% by mass or less, the amount of other components, such as rubber latex, blended into the adhesive composition can be kept at a certain level, resulting in improved adhesion to the rubber substrate.

[0180] In conventional adhesive compositions 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 resorcinol and formaldehyde, thereby providing good adhesion between the phenolic resin coating the surface of the organic fiber and the organic fiber.

[0181] On the other hand, in one preferred embodiment of the adhesive composition of the present invention, the aqueous compound having a (thermally dissociable, blocked) isocyanate group (C) acts as an adhesion promoter in place of the phenolic resin obtained by co-condensation of resorcinol and formaldehyde, due to the following two functional effects (x) and (y): As a result, in the adhesive composition, the aqueous compound having a (thermally dissociable, blocked) isocyanate group (C) contributes to the characteristic of good adhesion between the organic fiber and the coating rubber composition.

[0182] (x) the functional effect of distributing the aqueous compound near the interface between the organic fiber and the adhesive layer formed by the adhesive composition, thereby promoting adhesion between the organic fiber and the adhesive layer, and (y) the functional effect of forming a three-dimensional network structure within the adhesive layer formed by the adhesive composition through crosslinking by the isocyanate groups of the compound having a (thermally dissociable blocked) isocyanate group, thereby reinforcing the adhesive layer.

[0183] In one embodiment of the adhesive composition of the present invention, an example of the principle behind the functional effects (x) and (y) of the aqueous compound (C) having a (thermally dissociable blocked) isocyanate group as the two adhesion promoters will be described in detail below.

[0184] --Functional Effect of (x) as an Adhesion Promoter-- Synthetic resin materials commonly used as organic fibers, such as 6,6-nylon and polyethylene terephthalate, consist of flat, linear polymer chains. The surfaces of these polymer chains and the gaps between them possess a π-electron atmosphere derived from the aromatics and other components contained in the polymer chains. Therefore, adhesive compositions used with organic fibers such as polyester have traditionally contained, as an adhesion promoter, molecules with a planar structure (i.e., a portion that easily diffuses into organic fibers) having aromatic rings with aromatic π-electrons on their sides, with the aim of ensuring that the adhesive composition disperses into the gaps between the polymer chains of the organic fibers and that the adhesive layer formed by the adhesive composition adheres closely to the surfaces of the polymer chains of the organic fibers, thereby achieving sufficient adhesive strength. In the present invention, even for adhesive compositions that do not contain resorcinol, an aromatic compound, it is preferable to add an adhesion promoter with molecules with a planar structure (i.e., a portion that easily diffuses into organic fibers) having aromatic rings with aromatic π-electrons on their sides to promote adhesion, even in adhesive compositions for 6,6-nylon.

[0185] --Functional effect of (y) as an adhesion promoter-- When the adhesive composition contains an aqueous component having a plurality of phenolic hydroxy groups in the (D) molecule, in an adhesive layer containing the (C) component, the phenolic hydroxy groups of the aqueous component having a plurality of phenolic hydroxy groups in the (D) molecule form covalent bonds through isocyanate crosslinking with isocyanates from which the blocking agent has been dissociated by heat treatment, thereby strengthening the adhesion of the adhesive composition.

[0186] As mentioned above, the particle size of the component (C-1) is preferably 0.01 to 0.50 μm. When the particle size of the component (C-1) is 0.50 μm or less, the smaller the particle size, the less likely the component (C-1) is to settle in the liquid, and the less likely the component is to be dispersed non-uniformly in the adhesive layer. On the other hand, (C-2) is an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group. Because of its high water solubility, the component sedimentation in the adhesive composition liquid is less likely to occur, and there is little component non-uniformity even when the composition is stored stationary, which is preferable because it provides stable adhesion over time.

[0187] --Thermal Dissociative Blocking Agent, Aqueous Urethane Compound-- The thermal dissociative blocking agent of component (C-2) is not particularly limited as long as it is a blocking 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 thermal dissociative blocking agent include the same compounds as the blocking agents described above for component (C-1). 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; aromatic secondary amines such as diphenylamine and xylidine; and phthalimide. lactams such as δ-valerolactam; caprolactams such as ε-caprolactam; active methylene compounds such as dialkyl malonate, dimethyl malonate, and other malonic acid dialkyl esters, acetylacetone, and acetoacetic acid alkyl 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.

[0188] Among these blocking agents, phenol, ε-caprolactam, and ketoxime can be preferably used, as they are easily thermally dissociated by heating to stably achieve thermal curing of the adhesive composition.

[0189] Here, the term "aqueous" in the aqueous urethane compound means that the compound is water-soluble or water-dispersible. Furthermore, the term "water-soluble" does not necessarily mean that the compound is completely water-soluble, but rather that the compound is partially water-soluble or does not undergo phase separation in an aqueous solution of the adhesive composition.

[0190] The urethane compound of 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 means a compound represented by the following general formula (3). In the above formula (3), R and R' represent hydrocarbon groups.

[0191] The molecular weight of the aqueous urethane compound having a (thermally dissociable blocked) isocyanate group (C-2) is not particularly limited as long as it can maintain its aqueous nature, and the number average molecular weight is preferably 1,500 to 100,000, and particularly preferably 9,000 or less.

[0192] As mentioned above, the method for synthesizing the component (C-2) is not particularly limited, and can be a known method such as the method described in JP-A-63-51474.

[0193] --(C-2) Preferred Embodiment of Aqueous Urethane Compound Having (Thermally Dissociable Blocked) Isocyanate Groups-- A preferred embodiment of the component (C-2) is a reaction product obtained by mixing and reacting (α) an organic polyisocyanate compound having 3 to 5 functional groups and a number average molecular weight of 2,000 or less, (β) a compound having 2 to 4 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 hydrophilic group that is anionic, cationic, or nonionic, in a predetermined mixing ratio, wherein the constituent ratio of the (thermally dissociable blocked) isocyanate group in the reaction product is 0.5 to 11 mass % when the molecular weight of the isocyanate group (-NCO) is 42. Here, the mixing ratio of each of (α), (β), (γ), and (δ) relative to the total amount is 40% by mass or more and 85% by mass or less for (α), 5% by mass or more and 35% by mass or less for (β), 5% by mass or more and 35% by mass or less for (γ), and 5% by mass or more and 35% by mass or less for (δ). In this case, when the adhesive composition is used on organic fibers, the adhesion between the organic fibers and the coating rubber composition is further improved. This is because such component (C-2) has both a moiety consisting of a (thermally dissociable blocked)isocyanate group and a hydrophilic moiety having a hydrophilic group, thereby having the advantage of increasing the self-water solubility of the urethane compound.

[0194] 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, and may also be other aliphatic, alicyclic, or heterocyclic polyisocyanate compounds and their oligomers. This is because the component (C-2), which is the reaction product obtained after reacting such (α) organic polyisocyanate compound having 3 to 5 functional groups and a number-average molecular weight of 2,000 or less, is more easily dispersed in the gaps between the polymer chains of the organic fiber.

[0195] Specific examples of the aliphatic polyisocyanate compound 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 the alicyclic polyisocyanate compound include cyclobutane diisocyanate, cyclobutane diisocyanate, and cyclohexane diisocyanate. Examples of the heterocyclic polyisocyanate compounds include 1,3,5-tris(2'-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.

[0196] Among these, aromatic polyisocyanate compounds are preferred, and particularly preferred are methylene diphenyl polyisocyanate, polyphenylene polymethylene polyisocyanate, etc. In particular, polyphenylene polymethylene polyisocyanate having a number average molecular weight of 2,000 or less is preferred, and polyphenylene polymethylene polyisocyanate having a number average molecular weight of 1,000 or less is particularly preferred. This is because component (C-2), which is a reaction product obtained after reacting such an organic polyisocyanate compound (α) having 3 to 5 functional groups and a number average molecular weight of 2,000 or less, is more likely to disperse in the gaps between polymer chains of organic fibers.

[0197] The (β) compound having two or more and four 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) polyhydric amines 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 2 to 4 primary and / or secondary amino groups and hydroxyl groups 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 having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less, and copolymers thereof with other vinyl monomers, (vi) polychloroprene polyols having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less, and copolymers thereof with other vinyl monomers, (vii) polyether polyols having 2 to 4 hydroxyl groups and a number average molecular weight of 5,000 or less, C2-C4 alkylene oxide polyadducts of polyamines, polyhydric phenols and amino alcohols, C2-C4 alkylene oxide polyadducts of C3 or higher polyhydric alcohols, C2-C4 alkylene oxide copolymers, or C3-C4 alkylene oxide polymers.

[0198] Here, with regard to the component (C-2), the active hydrogen group refers to a group containing hydrogen that becomes active hydrogen (atomic hydrogen (hydrogen radical) and hydride ion (hydride)) when placed under suitable conditions. Examples of the active hydrogen group include an amino group and a hydroxyl group.

[0199] The compound having at least one active hydrogen group and at least one anionic hydrophilic group (δ) among the compounds 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.

[0200] The method for synthesizing the component (C-2) by mixing and reacting the components (α), (β), (γ), and (δ) is not particularly limited, but can be a known method such as the method described in JP-A-63-51474.

[0201] --(C-2) Another Preferred Embodiment of Aqueous Urethane Compound Having (Thermally Dissociable Blocked) Isocyanate Groups-- Another preferred embodiment of the component (C-2) is a reaction product obtained by mixing and reacting (α) an organic polyisocyanate compound having 3 to 5 functional groups and a number average molecular weight of 2,000 or less, (β) a compound having 2 to 4 active hydrogen groups and a number average molecular weight of 5,000 or less, (γ) a thermally dissociable blocking agent, (δ) a compound having at least one active hydrogen group and at least one anionic, cationic, or nonionic hydrophilic group, and (ε) a compound other than (α), (β), (γ), and (δ) that contains an active hydrogen group, in a predetermined mixing ratio, wherein the proportion of (thermally dissociable blocked) isocyanate groups in the reaction product is 0.5 to 11 mass %, where the molecular weight of the isocyanate group (-NCO) is 42. Here, the mixing ratio of each of (α), (β), (γ), (δ), and (ε) relative to the total amount is 40% by mass or more and less than 85% by mass for (α), 5% by mass or more and 35% by mass or less for (β), 5% by mass or more and 35% by mass or less for (γ), 5% by mass or more and 35% by mass or less for (δ), and more than 0% by mass and 45% by mass or less for (ε). This is because such a (C-2) component has both a moiety consisting of a (thermally dissociable blocked)isocyanate group and a hydrophilic moiety having a hydrophilic group, thereby providing the advantage of increasing the self-water solubility of the urethane compound.

[0202] 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 section “(C-2) Preferred embodiment of an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group” except for their mixing ratios.

[0203] The method for synthesizing the component (C-2) by mixing and reacting the components (α), (β), (γ), (δ), and (ε) is not particularly limited, but can be a known method such as the method described in JP-A-63-51474.

[0204] --(C-2) Yet Another Preferred Embodiment of an Aqueous Urethane Compound Having a (Thermally Dissociable Blocked) Isocyanate Group-- Yet another preferred embodiment of the component (C-2) is an aqueous urethane compound represented by the following general formula (1): [In formula (1), A represents a residue of an organic polyisocyanate compound from which an active hydrogen group has been eliminated, X represents a residue of a polyol compound having two or more and four 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 represents a residue of a thermally dissociable blocking agent from which an active hydrogen group has been eliminated, Z represents 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 an active hydrogen group has been eliminated, n represents an integer of 2 or more and 4 or less, and p + m represents an integer of 2 or more and 4 or less (m≧0.25)]. In this case, too, when the adhesive composition is used on organic fibers, the adhesion between the organic fibers and the coating rubber composition is further improved. This is because the component (C-2) has both a moiety consisting of a (thermally dissociable blocked) isocyanate group and a hydrophilic moiety having a hydrophilic group, thereby providing the advantage of increased self-water solubility of the urethane compound.

[0205] Here, the organic polyisocyanate compound A in general formula (1), which is the residue of the organic polyisocyanate compound from which the active hydrogen group has been eliminated, preferably contains an aromatic ring, because this makes it easier for the component (C-2) to disperse in the gaps between the polymer chains of the organic fiber.

[0206] Although not particularly limited, specific 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.

[0207] The polyol compound having two or more and four or less hydroxyl groups and a number average molecular weight of 5,000 or less, which is the residue obtained by eliminating the active hydrogen group from a polyol compound having two or more and four or less hydroxyl groups and a number average molecular weight of 5,000 or less, represented by X in general formula (1), is not particularly limited, but 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 2 to 4 primary and / or secondary amino groups and hydroxyl groups 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 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, C2-C4 alkylene oxide polyadducts of polyamines, polyhydric phenols and amino alcohols, C2-C4 alkylene oxide polyadducts of C3 or higher polyhydric alcohols, C2-C4 alkylene oxide copolymers, or C3-C4 alkylene oxide polymers.

[0208] The component (C-2) is not particularly limited, but commercially available products such as Elastron BN27, BN77, BN11, and F-2955-D manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. can also be used. Of these, Elastron BN77 is preferred.

[0209] When the adhesive composition of the present invention contains (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group, the mixing mass ratio [(A):(C)] (on a solids basis) is not particularly limited, but is preferably in the range of 100:0 to 100:80, more preferably in the range of 100:10 to 100:70, and even more preferably in the range of 100:20 to 100:60. A mixing mass ratio of 100:70 or less (a ratio value of 0.7 or less) is favorable because it reduces hardening of the adhesive composition associated with excessive crosslinking, allows the adhesive composition layer to maintain mobility when subjected to strain input during tire running, and prevents deterioration of the strength of the adhesive layer of the organic fiber coated with the adhesive composition or the organic fiber cord under strain.

[0210] Other additives that can be used in the adhesive composition of the present invention include polyvinyl alcohol, gum arabic, carrageenan, CMCs, water-soluble epoxide compounds, organic salts, or metal salts of aluminum, iron, chromium, copper, tin, nickel, titanium, etc. Furthermore, water-soluble liquids in which the film-forming material dissolves less than in water can also be used, such as alcohols such as ethanol and propanol, polyethylene glycol, glycerol, or water-soluble polymers such as isobutylene-maleic anhydride ring-opening copolymer salts.

[0211] <Method for producing adhesive composition> The adhesive composition of the present invention is characterized by containing (A) a rubber latex having an unsaturated diene, (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures or (meth)allyl structures in the molecule, and one or more compounds selected from the group consisting of the following (D) to (F): (D) an aqueous component having multiple phenolic hydroxy groups in the molecule, (E) an aqueous component having multiple amino groups in the molecule, and (F) a compound containing an amide bond structure, and preferably further contains (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group.

[0212] In producing the adhesive composition, (A) the rubber latex having an unsaturated diene, (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures or (meth)allyl structures in the molecule, and one or more compounds selected from the group consisting of (D) to (F), preferably further (C) an aqueous compound having a (thermally dissociable blocked)isocyanate group, can be mixed in any order.

[0213] Although not particularly limited, a preferred order of addition of the components to be contained in the adhesive composition is (D) an aqueous component having a plurality of phenolic hydroxy groups in the molecule, (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group, (E) an aqueous component having a plurality of amino groups in the molecule, (F) a compound containing an amide bond structure, (A) a rubber latex having an unsaturated diene, and (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule.

[0214] In the adhesive composition of the present invention, the mixing mass ratio [(A):(B)] (on a solids basis) of (A) the rubber latex having an unsaturated diene and (B) the aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule is not particularly limited, but is preferably in the range of 100:0.1 to 100:40, and more preferably in the range of 100:0.3 to 100:20. When the mixing mass ratio is 100:0.1 or more (a ratio value of 0.001 or more), a coating can be formed around the rubber latex having an unsaturated diene (A) as a core, which protects the latex particles, by the aqueous compound (B), and an adhesive layer with sufficient strength can also be obtained. Furthermore, when the mixing mass ratio is 100:40 or less (when the ratio value is 0.4 or less), the protective layer of the matrix of the aqueous compound (B) formed around the rubber latex having an unsaturated diene (A) as a core does not become too thick, and when the coated rubber composition as an adherend of organic fiber and the adhesive composition are co-vulcanized to bond them, the coated rubber composition as an adherend and the rubber latex having an unsaturated diene (A) are well miscible with each other, and as a result, the initial process of adhesion between the coated rubber composition as an adherend and the adhesive composition proceeds smoothly.

[0215] Furthermore, the components (A) to (F) of the adhesive composition of the present invention are preferably aqueous, since water, which is less polluting to the environment, can be used as the solvent.

[0216] [Organic Fiber Material] The adhesive composition configured as described above is applied to the surface of organic fibers, for example, organic fibers made of nylon resin, polyester resin, aromatic polyamide resin, acrylic resin, or the like, and then subjected to an appropriate heat treatment, whereby an adhesive layer made of the adhesive composition is applied to the surface of the organic fibers (resin substrate), thereby producing an adhesive-treated organic fiber material.

[0217] The organic fiber material of the present invention comprises organic fibers and an adhesive layer covering the surface of the organic fibers, the adhesive layer being made of the adhesive composition described above. This allows for an organic fiber material with excellent durability while ensuring environmental friendliness and workability. It is particularly preferred that the organic fibers be made of nylon resin, polyester resin, aromatic polyamide resin, or acrylic resin. Of these, nylon resin and polyester resin are preferred, and polyester resin was used in the examples described below. When the organic fibers are made of polyester resin, adhesiveness is further improved.

[0218] Methods for coating the surface of the organic fibers with the adhesive composition include immersing the organic fibers (particularly organic fiber cords) in the adhesive composition, applying the adhesive composition with a brush or the like, and spraying the adhesive composition, and an appropriate method can be selected as needed. The method for coating the surface of the organic fibers with the adhesive composition is not particularly limited, but when coating the surface of the organic fibers with the adhesive composition, it is preferable to dissolve the adhesive composition in various solvents to reduce the viscosity, as this makes coating (immersion, application, spraying, etc.) easier. Furthermore, it is environmentally preferable for the solvent for reducing the viscosity of the adhesive composition to consist mainly of water.

[0219] The solution concentration of the adhesive composition impregnated into the organic fibers 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, in terms of solid content, relative to the mass of the organic fibers.

[0220] Here, the thickness of the adhesive layer made of the adhesive composition is not particularly limited, but is preferably 50 μm or less, and more preferably 0.5 μm or more and 30 μm or less.

[0221] In particular, when the organic fiber-rubber composite of the present invention is applied to a tire, if 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 therefore undergoes relatively little deformation, but the deformation caused by strain increases with increasing distance from the interface. Compared to the adhered rubber material, the adhesive composition contains a large amount of thermosetting condensate, making it hard and brittle, which makes it 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.

[0222] The organic fiber is preferably an organic fiber cord formed by twisting together multiple filaments. Organic fiber cords formed by twisting together multiple filaments are suitable for reinforcing rubber articles such as tires and conveyor belts. Furthermore, when the organic fiber is an organic fiber cord, the adhesive layer in the organic fiber material preferably accounts for 0.5 to 6.0% by dry mass of the organic fiber cord. By ensuring that the dry mass of the adhesive layer falls within this range, appropriate adhesiveness can be ensured. Organic fiber cords are described in detail below.

[0223] The organic fibers coated with the adhesive composition can be subjected to drying, heat treatment, etc. in the same manner as in the case of the organic fiber material described above.

[0224] The organic fiber material, in which the surface of the organic fiber is coated with the adhesive composition, is preferably dried, for example, at a temperature of 100°C to 210°C, followed by heat treatment. This heat treatment is preferably carried out at a temperature equal to or higher than the glass transition temperature of the polymer of the organic fiber (resin substrate), preferably at a temperature equal to or higher than the melting temperature of the polymer minus 70°C and equal to or lower than the melting temperature minus 10°C. The reason for this is that below the glass transition temperature of the polymer, the molecular mobility of the polymer is poor, and the adhesive-promoting component of the adhesive composition and the polymer do not interact sufficiently, resulting in insufficient bonding strength between the adhesive composition and the organic fiber. Such organic fibers may be pretreated in advance with electron beams, microwaves, corona discharge, plasma treatment, or the like.

[0225] [Rubber Articles] The adhesive composition of the present invention described above can be suitably used for reinforcing various rubber articles. The rubber article of the present invention is characterized by being reinforced with the organic fiber material described above. This allows the rubber article to be excellent in durability while ensuring environmental friendliness and workability. Examples of such rubber articles of the present invention include tires, as well as conveyor belts, belts, hoses, air springs, etc.

[0226] [Organic Fiber-Rubber Composite] The organic fiber-rubber composite of the present invention is a composite of organic fiber and rubber, characterized in that the organic fiber is coated with the adhesive composition described above. This makes it possible to obtain good adhesion without using resorcinol, and to produce an organic fiber-rubber composite (particularly an organic fiber cord-rubber composite) that is environmentally friendly and easy to work with. The adhesive composition of the present invention particularly exhibits excellent adhesion between organic fibers such as organic fiber cords and the coated rubber composition.

[0227] Next, the organic fiber-rubber composite of the present invention will be described in detail with reference to Figure 2. Figure 2 is a cross-sectional schematic diagram showing an organic fiber cord-rubber composite, which is an example of the organic fiber-rubber composite of the present invention. In the organic fiber-rubber composite 31 shown in Figure 2, the outer surface in the outer diameter direction of an organic fiber cord 1 is coated with an adhesive layer 32 made of 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 adhesive composition 2, thereby forming the organic fiber-rubber composite 31 of the present invention.

[0228] The reinforcing material for rubber articles using the adhesive composition of the present invention may be in the form of short fibers, nonwoven fabrics, etc., in addition to the organic fiber cord-rubber composite.

[0229] <Organic Fiber Cord> An organic fiber cord, which is one example of the organic fiber, is used to supplement the strength of rubber articles such as tires. When using the organic fiber cord as a reinforcing material, first, spun organic fiber raw yarn is twisted to form an organic fiber cord. Then, the organic fiber cord is embedded in rubber that coats the organic fiber cord using an adhesive composition, and the organic fiber cord is bonded by vulcanization to produce an organic fiber-rubber composite, and this organic fiber-rubber composite can be used as a reinforcing member for rubber articles such as tires.

[0230] The material of the organic fiber is not particularly limited, but examples thereof include fiber materials typified by polyester fiber, nylon resin fibers such as 6-nylon, 6,6-nylon, and 4,6-nylon (aliphatic polyamide fiber), protein fibers such as artificial fibroin fiber, polyketone fiber, aromatic polyamide fibers typified by polynonamethylene terephthalamide and paraphenylene terephthalamide, acrylic fiber, carbon fiber, and cellulose fibers such as rayon and lyocell. Of these, polyester, 6-nylon, and 6,6-nylon are preferred, and polyester is particularly preferred.

[0231] The polyester material is a polymer having ester bonds in the main chain, specifically, 80% or more of the bonds in the repeating units in the main chain are ester bonds. This polyester is 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 transesterification reaction. The most representative polyester is polyethylene terephthalate.

[0232] 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 preferably an organic fiber cord formed by twisting together a top-twisted monofilament filament and a bottom-twisted monofilament filament. In other words, the organic fiber cord is preferably formed by twisting together a top twist and a top twist (i.e., the organic fiber cord is preferably a cord formed by twisting together a plurality of filaments, and the cord formed by twisting together a plurality of filaments has a top twist and a bottom twist). In this case, the fiber thickness of the organic fiber cord is preferably in the range of 100 dtex to 5000 dtex. Regarding the number of twists (turns / 10 cm), the number of first twists in the tire of the present invention is preferably 10 to 50 times / 10 cm. The number of top twists in the tire of the present invention is preferably 10 to 50 times / 10 cm. When the organic fiber cord is formed by first twisting and second twisting, the fiber thickness of the twisted cord is 100 dtex to 5000 dtex, and the number of twists is 10 to 50 times / 10 cm for the first twist and 10 to 50 times / 10 cm for the second twist, the organic fiber cord is more suitable for reinforcing rubber articles such as tires and conveyor belts.

[0233] In the present invention, it is preferable that the organic fiber is a polyethylene terephthalate tire cord having 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, and that the adhesive composition be adhered to this tire cord to form an organic fiber-rubber composite.

[0234] <Coating Rubber Composition for Organic Fiber-Rubber Composite> The coating rubber composition constituting the organic fiber-rubber composite of the present invention is preferably a rubber component blended with various 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. Of these, natural rubber and conjugated diene-based synthetic rubber are preferred. These rubber components may be used alone or in combination of two or more.

[0235] <Method for producing organic fiber-rubber composite> The organic fiber-rubber composite of the present invention is produced by coating organic fibers such as organic fiber cords with the adhesive composition 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 and the rubber component in the coating rubber composition that is the adherend of the organic fibers.

[0236] Finally, the organic fibers coated with the adhesive composition are bonded by co-vulcanizing the (A) unsaturated diene-containing rubber latex in the adhesive composition and the rubber component in the coating rubber composition that is the adherend of the organic fibers.

[0237] For the co-vulcanization of the rubber components in the coating rubber composition, organic vulcanizing agents such as sulfur, thiralium polysulfide compounds such as tetramethylthiralium disulfide and dipentamethylenethiralium tetrasulfide, 4,4-dithiomorpholine, p-quinone dioxime, p,p'-dibenzoquinone dioxime, and cyclic sulfur imide can be used. Of these, sulfur is preferably used. 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 compounded with the rubber components in the coating rubber composition.

[0238] Furthermore, it goes without saying that the adhesive composition of the present invention also provides an adhesive effect in an adhesion method in which a vulcanizing agent contained in an adherend made of a synthetic organic fiber material such as organic fiber and / or an adherend made of a coated rubber composition migrates to the adhesive composition, and the adhesive composition is crosslinked by the migrated vulcanizing agent.

[0239] [Tire] The tire of the present invention uses the organic fiber-rubber composite described above, which allows for good adhesion without using resorcinol, and allows for a tire with good environmental friendliness and productivity.

[0240] In the tire of the present invention, the organic fiber-rubber composite can be used as, for example, a carcass, a belt, a belt reinforcing layer, a reinforcing layer around the belt such as a flipper.

[0241] 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 fiber cords or the like treated with the adhesive composition described above at some location 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 can be normal air or air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, or helium.

[0242] The adhesive composition, organic fiber material, and 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, and air springs, in addition to the tires.

[0243] 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.

[0244] <(A) Rubber Latex Having Unsaturated Diene> In the following Comparative Examples 1 to 23 and Examples 1 to 21, a vinylpyridine-styrene-butadiene copolymer latex was used as the (A) rubber latex having unsaturated diene, prepared as follows in accordance with Comparative Example 1 described in JP-A-9-78045.

[0245] A 5-liter autoclave purged with nitrogen was charged with 130 parts by mass of deionized water and 4.0 parts by mass of potassium rosinate as an emulsifier, and dissolved therein. A monomer mixture consisting of 15 parts by mass of vinylpyridine monomer, 15 parts by mass of styrene, and 70 parts by mass of butadiene, and 0.60 parts by mass of t-dodecyl mercaptan as a chain transfer agent, were then charged and emulsified. The temperature was then raised to 50°C, and 0.5 parts by mass of potassium persulfate as a polymerization initiator was added to initiate polymerization. After the reaction rate of the monomer mixture reached 90%, 0.1 parts by mass 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 mass.

[0246] <(B) Aqueous Compound Having Two or More Polymerizable (meth)acrylate Structures, (meth)acrylamide Structures, or (meth)allyl Structures in the Molecule> In the following Comparative Examples 2 to 5, Comparative Examples 19 to 21, Examples 1 to 14, and Examples 15 to 21, the following compounds were used as the (B) aqueous compound component having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule: a compound (B-1) having two or more polymerizable (meth)acrylate structures and a polyglycerin structure in the molecule; a compound (B-2) having two or more polymerizable (meth)acrylamide structures and a main-chain-linked ether structure in the molecule; a compound (B-3) having two or more polymerizable (meth)acrylamide structures and a main-chain-linked amine structure in the molecule; and a compound (B-4) having two or more polymerizable (meth)acrylate monomers and a diallyldimethylammonium chloride structure in the molecule.

[0247] Here, (B-1) was manufactured by Sakamoto Yakuhin Kogyo Co., Ltd. under the trade name "SA-TE60" (liquid), (B-2) was manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. under the trade name "FOM-03006" (liquid), (B-3) was manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. under the trade name "FOM-03007" (liquid), and (B-4) was manufactured by Osaka Soda Co., Ltd. under the trade name "FOM-03007" (liquid), and (B-4) was manufactured by Sigma-Aldrich Japan LLC under the trade name "FOM-03007". These were diluted with deionized water while stirring to produce an aqueous solution with a solids concentration of 5% by mass, and this aqueous solution was used to prepare the adhesive composition.

[0248] <(C) Aqueous Compound Having a (Thermally Dissociable Blocked) Isocyanate Group> In the following Examples 11 to 14 and Examples 20 and 21, (C) the aqueous compound having a (thermally dissociable blocked) isocyanate group was used as is: (C-1) "DM-6400" manufactured by Meisei Chemical Industry Co., Ltd., which is a methyl ethyl ketoxime-blocked diphenylmethane diisocyanate compound (blocking agent thermal dissociation temperature: approximately 130°C, solids concentration: 40% by mass); and (C-2) "Elastron BN77 (F-2955D-1)" manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., which is an aqueous compound having a (thermally dissociable blocked) isocyanate group (blocking agent thermal dissociation temperature: approximately 160°C, pH 8.0, solids concentration: 31% by mass).

[0249] <(D) Aqueous Component Having Multiple Phenolic Hydroxy Groups in the Molecule> In the following Comparative Examples 6 to 7, Comparative Examples 15 to 18, Comparative Example 22, Examples 1 and 2, Examples 8 and 9, Examples 11 to 15, Example 18, and Examples 20 and 21, (D-1) a partially desulfonated lignin sulfonate having a reduced degree of sulfonation, manufactured by Tokyo Chemical Industry Co., Ltd., under the trade name "Lignin (Alkali)", and (D-2) a condensed tannin, manufactured by Kawamura Tsusho Co., Ltd., under the trade name "Mimosa", were used as the aqueous component (D) having multiple phenolic hydroxy groups in the molecule. These solid powder polyphenols were dissolved in deionized water adjusted to 80°C to produce an aqueous solution with a solids concentration of 10% by mass, and this aqueous solution was used in preparing an adhesive composition. In addition, as the aqueous component (D) having a plurality of phenolic hydroxy groups in the molecule, (D-3) kraft lignin was prepared using a product name "BioPiva 100" manufactured by UPM Biochemicals, and the temperature was adjusted to 80°C at a concentration of 1 x 10 －４ The resulting solution had a pH of 9.3 after dissolution.

[0250] <(E) Aqueous Component Having Multiple Amino Groups in the Molecule> In the following Comparative Examples 8 to 11, Comparative Example 15, Comparative Example 18, Comparative Example 23, Examples 3 to 5, Examples 10 and 11, Example 14, Example 16, and Examples 19 and 20, as the aqueous component (E) having multiple amino groups in the molecule, (E-1) a polypeptide having an amino group, manufactured by Ichimaru Pharcos Co., Ltd., trade name "Polylysine 10," (E-2) a polyetheramine, manufactured by BASF SE, trade name "Baxodur EC301," and (E-3) a polyethyleneimine, reagent "Polyethyleneimine Average Molecular Weight 600" manufactured by Wako Pure Chemical Industries, Ltd., were dissolved in deionized water with stirring to a solids concentration of 0.5% by mass, and the resulting aqueous solution was used to prepare an adhesive composition.

[0251] <(F) Compound Containing an Amide Bond Structure> In the following Comparative Examples 12 to 14, Comparative Examples 16 to 17, Comparative Example 23, Examples 6 and 7, and Examples 12 to 13, Example 17, Example 19, and Example 21, (F) the compound containing an amide bond structure was (F-1) a nonionic polyacrylamide manufactured by Harima Chemicals Co., Ltd. under the trade name "Haricoat 1057," and (F-2) an amphoteric polyacrylamide manufactured by Seiko PMC Corporation under the trade name "DS4441," as the compound containing an amide bond structure having a cationic group and a carboxyl group. These compounds were dissolved in deionized water with stirring to a solids concentration of 1% by mass, and the resulting aqueous solution was used to prepare an adhesive composition.

[0252] <Preparation of Latex Adhesive Composition (Comparative Example 1)> The above (A) rubber latex and water were blended (wet blending) as shown in Table 2, and the amounts were adjusted and mixed so that the solid content concentration was 21% by mass, followed by sufficient stirring to obtain a latex adhesive composition (Comparative Example 1).

[0253] <Preparation of Adhesive Compositions (Comparative Examples 2 to 23, Examples 1 to 21)> As shown in the formulations (wet formulations) in Tables 2 to 8, the following were blended in this order: water for dilution, (D) an aqueous component having multiple phenolic hydroxy groups in the molecule, (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group, (E) an aqueous component having multiple amino groups in the molecule, (F) a compound containing an amide bond structure, (A) a rubber latex having an unsaturated diene, and (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule. The resulting mixture was mixed so that the solids concentration of the adhesive composition was 21% by mass, and then thoroughly stirred to obtain an adhesive composition according to one embodiment of the present invention.

[0254] <Coating of tire cord with each adhesive composition> As the organic fiber cord, a polyethylene terephthalate tire cord having 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.

[0255] The tire cord was immersed in each of the adhesive compositions of Comparative Examples 1 to 23 and Examples 1 to 21 so that the concentration of the adhesive composition impregnated into the tire cord was 3.5% by mass relative to the mass of the organic fiber cord. The tire cord was then sequentially subjected to drying in a drying zone (135°C, 80 seconds), heat curing of the resin in a hot zone (238°C, 60 seconds) while applying a tension (33 N / cord), and heat curing in a normalization zone (238°C, 60 seconds) while releasing the tension, thereby obtaining tire cords coated with the adhesive compositions of each Comparative Example and Example.

[0256] <Preparation of Tire Cord-Rubber Composite> Tire cords coated with each of the adhesive compositions of Comparative Examples 1 to 23 and Examples 1 to 21 were embedded in an unvulcanized rubber composition and co-vulcanized at 160° 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, etc.

[0257] <Evaluation of Workability of Adhesive Composition> The workability of the adhesive compositions of each of the comparative examples and examples was evaluated as follows.

[0258] (1) Evaluation of Mechanical Stability (Solidification Rate) The mechanical stability (solidification rate) of each adhesive composition was measured in accordance with the method specified in JIS K6392-1995 using a Maron mechanical stability tester for copolymer latex compositions (Maron stability tester No. 2312-II, manufactured by Kumagai Riki Kogyo Co., Ltd.).

[0259] In summary, each adhesive composition was subjected to shear strain for 10 minutes using the rotor of the Maron mechanical stability tester at a compression load of 10 kg and a rotation speed of 1000 r / min, and then the solidification rate (%) was evaluated using the following formula based on the amount of solidified material that was generated, and rounded off to three decimal places to obtain a value. A smaller value indicates better mechanical stability. Solidification rate (%) = [(dry mass of generated solidified material) / (mass of solid content of test adhesive liquid)] x 100

[0260] (2) Evaluation of Adhesion to Squeeze Roll The above-mentioned polyethylene terephthalate tire cord, which is an organic fiber cord, was continuously treated for 2000 m in a dipping treatment machine storing each adhesive composition, and the amount of each adhesive composition adhering to the roll in the resin heat curing zone (238°C, 60 seconds) while applying tension (33 N / cord) in the hot zone was visually observed and evaluated on the following 5-point scale: Extra large: Very large; Large: Large; Medium: Medium; Small: Small; Slight: Very small.

[0261] <Evaluation of Adhesion Properties of Adhesive Compositions> The adhesive properties of the adhesive compositions of each of the comparative examples and examples were evaluated as follows.

[0262] (3) Evaluation of Adhesion Strength The tire cord-rubber composite obtained using each adhesive composition was pulled at a rate of 300 mm / min to peel the tire cord from the tire cord-rubber composite, and the peel resistance per tire cord was determined, which was taken as the room temperature adhesive strength (N / cord). In addition, a similar cord peel resistance test was performed by leaving the tire cord in an oven at 100°C for 5 minutes and then peeling it at the same temperature, and the peel resistance per tire cord was determined, which was taken as the high temperature adhesive strength (N / cord).

[0263] (4) Evaluation of Adhesion State of Covering Rubber The tire cords peeled from the tire cord-rubber composite were visually observed for adhesion state of the covering rubber, and scored according to Table 1 below.

[0264]

[0265] <Results of Workability Evaluation and Adhesion Evaluation of Adhesive Compositions> The formulations of the adhesive compositions of each Comparative Example and Example are shown in Tables 2 to 8 below, and the results of the workability evaluation and adhesion evaluation are shown in Tables 2 to 8 below, respectively.

[0266]

[0267]

[0268]

[0269]

[0270]

[0271]

[0272]

[0273] (A-1): Rubber latex having an unsaturated diene, vinylpyridine-styrene-butadiene copolymer latex synthesized by the above method, solid content concentration 41% by mass

[0274] (B-1): A compound containing two or more polymerizable (meth)acrylate structures and a polyglycerin structure in the molecule, polyglycerin-based (meth)acrylate, manufactured by Sakamoto Pharmaceutical Co., Ltd., trade name "SA-TE60", soluble in water, liquid. (B-2): A compound containing two or more polymerizable (meth)acrylamide structures and a main chain-linked ether structure in the molecule, N,N'-{[(2-acrylamido-2-[(3-acrylamidopropoxy)methyl]propane-1,3-diyl)bis(oxy)]bis(propane-1,3-diyl)}diacrylamide, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "FOM-03006", soluble in water, liquid. (B-3): Compound containing two or more polymerizable (meth)acrylamide structures and main chain-linked amine structures in the molecule, N,N',N''-triacryloyldiethylenetriamine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "FOM-03007", soluble in water, liquid (B-4-1): Compound containing two or more polymerizable (meth)allyl structures and dimethylammonium chloride structures in the molecule, diallyldimethylammonium chloride, manufactured by Osaka Sword Co., Ltd., trade name "DADMAC", 60 wt% aqueous solution (B-4-2): Compound containing two or more polymerizable (meth)allyl structures and dimethylammonium chloride structures in the molecule, poly(diallyldimethylammonium chloride), reagent manufactured by Sigma-Aldrich Japan LLC, CAS number: 26062-79-3, average molecular weight Mw = 200,000-350,000, 20 wt% aqueous solution

[0275] (C-1): Aqueous compound having a (thermally dissociable blocked) isocyanate group, manufactured by Meisei Chemical Industry Co., Ltd., trade name "DM-6400" (blocking agent thermal dissociation temperature: approximately 130°C, solid content concentration: 40% by mass), methyl ethyl ketoxime-blocked diphenylmethane diisocyanate compound, aqueous dispersion. (C-2): Aqueous compound having a (thermally dissociable blocked) isocyanate group, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name "Elastron BN77 (F-2955D-1)" (blocking agent thermal dissociation temperature: approximately 160°C, pH 8.0, solid content concentration: 31% by mass), aqueous dispersion.

[0276] (D-1): Polyphenol (lignin sulfonate), manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Lignin (dealkalized)" (CAS Number: 8061-51-6), partially desulfonated lignin sulfonate with reduced degree of sulfonation, solid powder. (D-2): Polyphenol (condensed tannin), manufactured by Kawamura Tsusho Co., Ltd., trade name "Mimosa", solid powder. (D-3): Kraft lignin, manufactured by UPM Biochemicals, trade name "BioPiva 100" (CAS Number: 8068-5-01), kraft lignin sulfonate, solid powder.

[0277] (E-1): Polylysine, a polypeptide having an amino group, manufactured by Ichimaru Pharcos Co., Ltd., trade name "Polylysine 10" (solid content concentration 10%, aqueous solution), weight average molecular weight 5000. (E-2): Polyetheramine, manufactured by BASF SE, trade name "Baxodur EC301" (CAS number: 9046-10-0, nominal molecular weight Mw: 230, nominal amine hydrogen equivalent: 61 g / Eq, specific gravity: 0.95), colorless liquid. (E-3): Polyethyleneimine, a reagent manufactured by Wako Pure Chemical Industries, Ltd., "Polyethyleneimine average molecular weight 600", solid content 100%, liquid.

[0278] (F-1): Nonionic polyacrylamide, trade name "Haricoat 1057" (20% solids aqueous solution) manufactured by Harima Chemicals Co., Ltd. (F-2): Amphoteric polyacrylamide, trade name "DS4441" (20% solids aqueous solution) manufactured by Seiko PMC Corporation

[0279] It can be seen from Tables 5 to 8 that in each Example, an adhesive composition was obtained that had good workability and good adhesion between the organic fiber and the coating rubber composition. Furthermore, it can be seen that, in particular, when (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule is contained, roll scale in a high-temperature furnace is reduced, and the high-temperature adhesive strength is further improved.

[0280] According to the present invention, it is possible to provide an adhesive composition that can ensure desired adhesiveness without using resorcinol and that does not impair workability during use, as well as an organic fiber material, a rubber article, an organic fiber-rubber composite, and a tire that use the adhesive composition. Therefore, the present invention can be used in industrial fields that manufacture rubber articles such as tires.

[0281] 1: Organic fiber cord 2: Adhesive composition 3: Dipping bath 4: Organic fiber cord coated with adhesive composition 5: Squeeze roll 6: Drying zone 7: Hot zone 8: Normalization zone 31: Organic fiber-rubber composite 32: Adhesive layer made of adhesive composition 33: Coated rubber composition

Claims

1. An adhesive composition comprising: (A) a rubber latex having an unsaturated diene; and (B) an aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures, or (meth)allyl structures in the molecule, further comprising one or more compounds selected from the group consisting of (D) to (F) below: (D) an aqueous component having multiple phenolic hydroxy groups in the molecule; (E) an aqueous component having multiple amino groups in the molecule; and (F) a compound containing an amide bond structure.

2. The adhesive composition according to claim 1, further comprising (C) an aqueous compound having a (thermally dissociable blocked) isocyanate group.

3. The adhesive composition according to claim 1 or 2, wherein the (A) rubber latex having an unsaturated diene comprises at least one selected from the group consisting of natural rubber (NR), isoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), halogenated butyl rubber, acrylonitrile-butadiene copolymer rubber (NBR) and vinylpyridine-styrene-butadiene copolymer rubber (Vp).

4. The adhesive composition according to claim 1 or 2, wherein (B) the aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures or (meth)allyl structures in the molecule is an aqueous compound containing a polyether structure in the molecule.

5. The adhesive composition according to claim 1 or 2, wherein the (B) aqueous compound having two or more polymerizable (meth)acrylate structures, (meth)acrylamide structures or (meth)allyl structures within the molecule is (B-1) a compound containing two or more polymerizable (meth)acrylate structures and a polyglycerin structure within the molecule, (B-2) a compound containing two or more polymerizable (meth)acrylamide structures and a main chain linking ether structure within the molecule, (B-3) a compound containing two or more polymerizable (meth)acrylamide structures and a main chain linking amine structure within the molecule, or (B-4) a compound containing two or more polymerizable (meth)allyl structures and a dimethylammonium chloride structure within the molecule.

6. The adhesive composition according to claim 1 or 2, wherein (D) the aqueous component having a plurality of phenolic hydroxy groups in its molecule is a plant-derived component having a plurality of phenolic hydroxy groups in its molecule.

7. The adhesive composition according to claim 6, wherein the aqueous component (D) having a plurality of phenolic hydroxy groups in the molecule is lignin, tannin, tannic acid, a flavonoid, or a derivative thereof.

8. The adhesive composition according to claim 7, wherein (D) the aqueous component having a plurality of phenolic hydroxy groups in the molecule is a derivative of lignin sulfonic acid.

9. The adhesive composition according to claim 1 or 2, wherein the (E) aqueous component having a plurality of amino groups in the molecule is (E-1) a polypeptide having an amino group, (E-2) a polyetheramine, (E-3) a polyethyleneimine, or (E-4) a polyamidoamine.

10. The adhesive composition according to claim 9, wherein the aqueous component (E) having a plurality of amino groups in the molecule is polylysine.

11. The adhesive composition according to claim 1 or 2, wherein the compound (F) containing an amide bond structure is a polymer made of (meth)acrylamide or a copolymer containing (meth)acrylamide and another polymerizable monomer.

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

13. The adhesive composition according to claim 12, 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.

14. The adhesive composition according to claim 2, wherein the (C) aqueous compound having a (thermally dissociable blocked) isocyanate group is (C-2) an aqueous urethane compound having a (thermally dissociable blocked) isocyanate group.

15. The (C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group comprises: (α) an organic polyisocyanate compound having 3 to 5 functional groups and a number average molecular weight of 2,000 or less; (β) a compound having 2 to 4 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 hydrophilic group that is anionic, cationic or nonionic, in a mixing ratio of each of (α), (β), (γ) and (δ) relative to the total amount of (α), (β), (γ) and (δ) that 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; and reacting the components so that the molecular weight of the isocyanate group (-NCO) is 42, the component ratio of the (thermally dissociable blocked) isocyanate group in the reaction product is 0.5 mass % or more and 11 mass % or less.

16. The (C-2) aqueous urethane compound having a (thermally dissociable blocked) isocyanate group is represented by the following general formula (1):

16. The adhesive composition according to claim 14 or 15, represented by formula (1): [in formula (1), A represents a residue of an organic polyisocyanate compound from which an active hydrogen group has been removed, X represents 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 removed, Y represents a residue of a thermally dissociable blocking agent from which an active hydrogen group has been removed, Z represents 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 an active hydrogen group has been removed, n represents an integer of 2 or more and 4 or less, and p+m represents an integer of 2 or more and 4 or less (m≧0.25)] 17. The adhesive composition according to claim 1 or 2, which does not contain resorcinol.

18. The adhesive composition according to claim 1 or 2, which does not contain a photoinitiator.

19. The adhesive composition according to claim 1 or 2, which is for adhesion to rubber.

20. The adhesive composition according to claim 1 or 2, which is for bonding to organic fibers.

21. The adhesive composition according to claim 1 or 2, which is used for bonding rubber to organic fibers.

22. An organic fiber material comprising organic fibers and an adhesive layer covering the surface of the organic fibers, characterized in that the adhesive layer is made of the adhesive composition described in claim 1 or 2.

23. The organic fiber material according to claim 22, wherein the organic fiber is an organic fiber cord made by twisting together a plurality of filaments.

24. The organic fiber material according to claim 23, wherein the organic fiber cord is formed by first twisting and second twisting, the fiber thickness of the twisted cord is 100 dtex to 5000 dtex, and the number of twists in the twisted cord is 10 to 50 times / 10 cm for the first twist and 10 to 50 times / 10 cm for the second twist.

25. The organic fiber material according to claim 23, wherein the adhesive layer has a dry mass of 0.5 to 6.0 mass % of the mass of the organic fiber cord.

26. The organic fiber material of claim 22, wherein the organic fibers are made of a polyester resin.

27. A rubber article, characterized in that it is reinforced with the organic fiber material according to claim 22.

28. An organic fiber-rubber composite, comprising an organic fiber and rubber, the organic fiber being coated with the adhesive composition according to claim 1 or 2.

29. A tire using the organic fiber-rubber composite material according to claim 28.

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