Adhesive composition, rubber-organic fiber cord composite, and tire

Abstract

The present invention addresses the problem of providing an adhesive composition that can achieve excellent adhesion even when resorcin is not included therein, as well as a rubber-organic fiber cord composite and a tire that have a light impact on the environment, high producibility, and excellent adhesion between the rubber and the organic fiber cord. This problem is solved by an adhesive composition that is characterized by including a polyphenol and formaldehyde, a rubber-organic fiber cord composite that is characterized by comprising a rubber member and an organic fiber cord wherein at least a portion of the organic fiber cord is coated with said adhesive composition, and a tire that is characterized by comprising said rubber-organic fiber cord composite.

Description

Technical Field

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

Background Art

[0002] Conventionally, organic fibers such as polyester fibers have high initial elastic modulus and excellent thermal dimensional stability, and thus are used as reinforcing materials for rubber articles such as tires, belts, air springs, and rubber hoses in the form of filaments, cords, cables, cord fabrics, canvases, etc. Also, various adhesive compositions have been proposed to improve the adhesiveness between these fibers and rubber. For example, as the adhesive composition, a technique is known in which an RFL (resorcinol-formalin-latex) adhesive containing resorcinol, formalin, rubber latex, etc. is used, and the adhesive force is ensured by thermally curing the RFL adhesive (Patent Documents 1 to 3).

[0003] Regarding the adhesive composition, a technique using a resorcinol formalin resin obtained by initially condensing resorcinol and formalin (Patent Documents 4 and 5), and a technique for improving the adhesive force by pretreating a tire cord made of polyester fiber or the like with an epoxy resin are known.

[0004] Here, resorcinol generally used in the above-mentioned adhesive composition is required to reduce the usage amount from the viewpoint of the environment. Therefore, several adhesive compositions and adhesion methods that do not contain resorcinol and consider the environment have been proposed (Patent Document 6).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, an adhesive composition that does not contain resorcin requires time for curing, and thus further improvement is required in terms of productivity and adhesiveness.

[0007] Therefore, an object of the present invention is to provide an adhesive composition that solves the above problems of the prior art and can achieve excellent adhesiveness even when resorcin is not contained. Another object of the present invention is to provide a rubber-organic fiber cord composite and a tire that have less environmental impact, high productivity, and excellent adhesiveness between the rubber and the organic fiber cord.

Means for Solving the Problems

[0008] The gist of the present invention for solving the above problems is as follows.

[0009] The adhesive composition of the present invention is characterized by containing polyphenols and formaldehyde. Such an adhesive composition of the present invention can achieve excellent adhesiveness even when resorcin is not contained.

[0010] In a preferred example of the adhesive composition of the present invention, the polyphenols have three or more hydroxyl groups. In this case, more excellent adhesiveness can be achieved.

[0011] In another preferred example of the adhesive composition of the present invention, the polyphenols are at least one selected from the group consisting of phloroglucinol, morin, phloroglucide, lignin, and tannin. Also in this case, more excellent adhesiveness can be realized.

[0012] The adhesive composition of the present invention preferably further contains an isocyanate compound. Also in this case, more excellent adhesiveness can be realized.

[0013] Here, the isocyanate compound is preferably an (blocked) isocyanate group-containing aromatic compound. In this case, even more excellent adhesiveness can be realized.

[0014] The adhesive composition of the present invention preferably further contains a rubber latex. Also in this case, more excellent adhesiveness can be realized.

[0015] Here, the rubber latex preferably 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 rubber (NBR), and vinyl pyridine-styrene-butadiene copolymer rubber (Vp). In this case, even more excellent adhesiveness can be realized.

[0016] Further, the total content of the polyphenols and the formaldehyde is preferably 5 to 65% by mass in terms of solid content, the content of the latex is preferably 30 to 95% by mass in terms of solid content, and the content of other components is 0 to 65% by mass. In this case, even more excellent adhesiveness can be realized.

[0017] Since the adhesive composition of the present invention can improve the adhesiveness between the organic fiber cord and the rubber, it is preferable as an adhesive composition for organic fiber cords.

[0018] Further, the rubber-organic fiber cord composite of the present invention comprises a rubber member and an organic fiber cord. At least a part of the organic fiber cord is coated with the above adhesive composition. The rubber-organic fiber cord composite of the present invention has excellent adhesion between the rubber and the organic fiber cord.

[0019] Further, the tire of the present invention comprises the above rubber-organic fiber cord composite. The tire of the present invention has excellent adhesion between the rubber and the organic fiber cord.

Effect of the Invention

[0020] According to the present invention, an adhesive composition capable of achieving excellent adhesion even when resorcinol is not contained can be provided. Further, according to the present invention, a rubber-organic fiber cord composite and a tire with less environmental load, high productivity, and excellent adhesion between the rubber and the organic fiber cord can be provided.

Mode for Carrying Out the Invention

[0021] Hereinafter, the adhesive composition, rubber-organic fiber cord composite, and tire of the present invention will be specifically illustrated and described based on their embodiments.

[0022] <Adhesive Composition> The adhesive composition of the present invention is characterized by containing polyphenols and formaldehyde. Since resorcinol is not used in the adhesive composition of the present invention, the environmental load can be reduced. Further, the polyphenols used in place of resorcinol form a polyphenols / formaldehyde resin together with formaldehyde, and the resin has an adhesive action equivalent to that of the resorcinol / formaldehyde resin. Therefore, by treating the organic fiber cord with an adhesive composition containing polyphenols and formaldehyde, the adhesion between the organic fiber cord and the rubber can be improved. Therefore, even when the adhesive composition of the present invention does not contain resorcinol, excellent adhesiveness can be achieved. Further, the adhesive composition of the present invention is preferable as an adhesive composition for organic fiber cords.

[0023] (Polyphenols) The adhesive composition contains polyphenols as a resin component. By including polyphenols in the adhesive composition, the adhesiveness of the resin composition can be enhanced. Here, the polyphenols are water-soluble polyphenols, and there is no limitation as long as they are polyphenols other than resorcinol (resorcinol), and the number of aromatic rings and the number of hydroxyl groups can be appropriately selected.

[0024] Further, from the viewpoint of achieving more excellent adhesiveness, the polyphenols preferably have two or more hydroxyl groups, and more preferably have three or more hydroxyl groups. By having three or more hydroxyl groups, the polyphenols or the condensate of the polyphenols can be more dissolved in the adhesive composition liquid containing moisture and can be uniformly distributed in the adhesive composition, so that more excellent adhesiveness can be achieved. Furthermore, when the polyphenols are polyphenols containing a plurality (two or more) of aromatic rings, in each of those aromatic rings, two or three hydroxyl groups are present at the ortho, meta or para positions.

[0025] Examples of the polyphenols having three or more hydroxyl groups described above include phloroglucinol represented by the following structural formula (1), morin (i.e., 2’,4’,3,5,7-pentahydroxyflavone) represented by the following structural formula (2), phloroglucide (i.e., 2,4,6,3’,5’-biphenylpentol) represented by the following structural formula (3), and further lignin, tannin, etc. obtained from various plants. [Chemical formula]

[0026] The lignin and tannin are obtained from plants, but the plants of origin are not particularly limited. Further, the lignin and tannin may be natural products themselves or may be those subjected to various chemical treatments. For example, examples of the lignin include delignified lignin, alkali lignin, sodium sulfonate lignin, and the like. Examples of the tannin include plant tannin derived from mimosa, plant tannin derived from quebracho, and the like.

[0027] The polyphenols may be used alone or in combination of two or more. Further, the content of the polyphenols in the adhesive composition is preferably adjusted as appropriate so that the mass ratio as the solid content with formaldehyde described later is within a suitable range.

[0028] (Formaldehyde) The adhesive composition contains formaldehyde as a resin component in addition to the polyphenols described above. By containing formaldehyde in the adhesive composition, high adhesiveness can be achieved together with the polyphenols described above.

[0029] In the adhesive composition, the polyphenols and formaldehyde are in a condensed state, and the mass ratio of the polyphenols to formaldehyde (content of formaldehyde / content of polyphenols) is preferably 0.1 or more and 3 or less, and more preferably 0.15 or more and 2.5 or less. A condensation reaction occurs between the polyphenols and formaldehyde, but if it is within the suitable range of the above mass ratio, the hardness and adhesiveness of the resulting resin will be more suitable.

[0030] Further, the total content of the polyphenols and formaldehyde in the adhesive composition is preferably 5 to 65% by mass, more preferably 5 to 50% by mass, and still more preferably 5 to 40% by mass. This is because within this suitable range, excellent adhesiveness can be ensured without deteriorating workability and the like. In addition, the mass ratio and total content of the polyphenols and formaldehyde are values in terms of the mass of the dried product (solid content ratio).

[0031] (Isocyanate compound) Preferably, the adhesive composition further contains an isocyanate compound in addition to the polyphenols and formaldehyde described above. When the adhesive composition contains an isocyanate compound, the adhesiveness of the adhesive composition can be greatly enhanced by the synergistic effect with the polyphenols and formaldehyde. Here, the isocyanate compound is a compound having an action of promoting adhesion to a resin material (for example, organic fiber cord) which is an adherend of the adhesive composition, and is a compound having an isocyanate group as a polar functional group.

[0032] The type of the isocyanate compound is not particularly limited, but from the viewpoint of further improving adhesiveness, it is preferably an (blocked) isocyanate group-containing aromatic compound. When the isocyanate compound is contained in the adhesive composition, the (blocked) isocyanate group-containing aromatic compound is distributed in the vicinity of the interface between the adherend fiber and the adhesive composition, and an effect of promoting adhesion can be obtained. By this action effect, the adhesion with the organic fiber cord can be further enhanced. The (blocked) isocyanate group-containing aromatic compound is an aromatic compound having a (blocked) isocyanate group. The term "(blocked) isocyanate group" means a blocked isocyanate group or an isocyanate group, and includes, in addition to the isocyanate group, a blocked isocyanate group generated by reacting with a blocking agent for the isocyanate group, an unreacted isocyanate group with respect to the isocyanate group, or an isocyanate group generated by dissociation of the blocking agent of the blocked isocyanate group.

[0033] Furthermore, the (blocked) isocyanate group-containing aromatic compound preferably includes a molecular structure in which aromatics are bonded by an alkylene chain, and more preferably includes a molecular structure in which aromatics are methylene-bonded. Examples of the molecular structure in which aromatics are bonded by an alkylene chain include molecular structures found in diphenylmethane diisocyanate, polyphenylene polymethylene polyisocyanate, condensates of phenols and formaldehyde, and the like.

[0034] Examples of the (blocked) isocyanate group-containing aromatic compound include compounds containing an aromatic polyisocyanate and a thermal dissociation blocking agent, water-dispersible compounds containing components obtained by blocking diphenylmethane diisocyanate or an aromatic polyisocyanate with a thermal dissociation blocking agent, aqueous urethane compounds, and the like.

[0035] Preferred examples of the compound containing an aromatic polyisocyanate and a thermal dissociation blocking agent include blocked isocyanate compounds containing diphenylmethane diisocyanate and a known isocyanate blocking agent. Examples of the water-dispersible compound containing components obtained by blocking diphenylmethane diisocyanate or an aromatic polyisocyanate with a thermal dissociation blocking agent include reaction products obtained by blocking diphenylmethane diisocyanate or polymethylene polyphenyl polyisocyanate with a known blocking agent for blocking isocyanate groups. Specifically, commercially available blocked polyisocyanate compounds such as Elastron BN69 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Elastron BN77 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and Makeanate TP-10 (manufactured by Meisei Chemical Industry Co., Ltd.) can be used.

[0036] The aqueous urethane compound is obtained by reacting an organic polyisocyanate compound (α) containing a molecular structure in which aromatics are bonded by an alkylene chain, preferably a molecular structure in which aromatics are methylene-bonded, a compound (β) having a plurality of active hydrogens, and a thermal dissociable blocking agent (γ) for isocyanate groups. Further, due to its flexible molecular structure, the aqueous urethane compound has not only the function as an adhesion improver but also the function of suppressing the fluidization of the adhesive at high temperatures as a flexible crosslinking agent. Note that "aqueous" indicates water solubility or water dispersibility, and "water solubility" does not necessarily mean complete water solubility, but means partially water-soluble or those that do not phase-separate in the aqueous solution of the adhesive composition of the present invention.

[0037] Here, as the aqueous urethane compound, for example, the following general formula (4): [Chemical formula] [In the formula, A represents the residue obtained by eliminating the active hydrogen of the organic polyisocyanate compound (α) containing a molecular structure in which aromatics are bonded by an alkylene chain, Y represents the residue obtained by eliminating the active hydrogen of the thermal dissociable blocking agent (γ) for isocyanate groups, Z represents the residue obtained by eliminating the active hydrogen of the compound (δ), X is the residue obtained by eliminating the active hydrogen of the compound (β) having a plurality of active hydrogens, n is an integer of 2 to 4, and p + m is an integer of 2 to 4 (m ≥ 0.25).] The aqueous urethane compound represented thereby is preferred.

[0038] Examples of the organic polyisocyanate compound (α) containing a molecular structure in which aromatics are bonded by an alkylene chain include methylene diphenyl polyisocyanate and polymethylene polyphenyl polyisocyanate. Further, the compound (β) having a plurality of active hydrogens preferably has 2 to 4 active hydrogens and is a compound having an average molecular weight of 5,000 or less. Examples of such a compound (β) include (i) polyhydric alcohols having 2 to 4 hydroxyl groups, (ii) polyvalent amines having 2 to 4 primary and / or secondary amino groups, (iii) amino alcohols having 2 to 4 primary and / or secondary amino groups and hydroxyl groups, (iv) polyester polyols having 2 to 4 hydroxyl groups, (v) polybutadiene polyols having 2 to 4 hydroxyl groups and copolymers thereof with other vinyl monomers, (vi) polychloroprene polyols having 2 to 4 hydroxyl groups and copolymers thereof with other vinyl monomers, and (vii) polyether polyols having 2 to 4 hydroxyl groups, which are C2-C4 alkylene oxide adducts of polyvalent amines, polyvalent phenols, and amino alcohols, C2-C4 alkylene oxide adducts of polyhydric alcohols having 3 or more carbon atoms, C2-C4 alkylene oxide copolymers, or C3-C4 alkylene oxide polymers, etc. Furthermore, the thermally dissociable blocking agent (γ) for the isocyanate group is a compound capable of liberating the isocyanate group by heat treatment, and examples thereof include known isocyanate blocking agents. Furthermore, the compound (δ) is a compound having at least one active hydrogen and an anionic and / or nonionic hydrophilic group. Examples of the compound having at least one active hydrogen and an anionic hydrophilic group include aminosulfonic acids such as taurine, N-methyltaurine, N-butyltaurine, and sulfanilic acid, and aminocarboxylic acids such as glycine and alanine. On the other hand, examples of the compound having at least one active hydrogen and a nonionic hydrophilic group include compounds having a hydrophilic polyether chain.

[0039] In addition, the content of the isocyanate compound in the adhesive composition is not particularly limited, but from the viewpoint of more reliably ensuring excellent adhesiveness, it is preferably in the range of 5 to 65% by mass, and more preferably 10 to 45% by mass. The content of the isocyanate compound is a value in terms of the mass of the dried product (solid content ratio).

[0040] (rubber latex) In addition to the polyphenols, formaldehyde, and isocyanate compound described above, the adhesive composition can further substantially contain rubber latex. By including rubber latex in the adhesive composition, the adhesiveness to rubber members can be further enhanced.

[0041] The rubber latex is obtained by dispersing fine particles of a rubber component in water or the like. The concentration of the rubber component in the rubber latex is preferably in the range of 10 to 60% by mass, and more preferably in the range of 20 to 50% by mass. Here, the rubber component of the rubber latex is not particularly limited, and in addition to natural rubber (NR), 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 rubber (NBR), and vinyl pyridine-styrene-butadiene copolymer rubber (Vp) can be used. These rubber components may be used alone or in combination of two or more.

[0042] Also, with respect to the rubber latex, it is preferable to mix it with the polyphenols and the formaldehyde before blending the isocyanate compound. Furthermore, the content of the rubber latex in the adhesive composition is preferably 30 to 95% by mass, more preferably 40 to 90% by mass, and even more preferably 50 to 85% by mass as the solid content (rubber component).

[0043] The total content of the polyphenols and the formaldehyde in the adhesive composition is preferably 5 to 65% by mass in terms of solid content, the content of the latex is preferably 30 to 95% by mass in terms of solid content, and the content of other components is preferably 0 to 65% by mass. In this case, even better adhesion can be achieved.

[0044] (Method for producing the adhesive composition) The method for producing the adhesive composition is not particularly limited. For example, there are a method of mixing raw materials such as the polyphenols, formaldehyde, and the rubber latex and aging them, or a method of mixing and aging the polyphenols and formaldehyde and then further adding the rubber latex and aging. When the isocyanate compound is included, the rubber latex can be added, aged, and then the isocyanate compound can be added. Also, the polyphenols and formaldehyde are preferably dissolved in water and used as an aqueous solution. At this time, when the polyphenols are difficult to dissolve in water, it is preferable to heat the water to a temperature of preferably 40°C or higher, more preferably 60°C or higher. Alternatively, it is also preferable to add an aqueous sodium hydroxide solution, an aqueous ammonia solution, etc. to the water to make it alkaline.

[0045] <Rubber - organic fiber cord composite> The rubber - organic fiber cord composite of the present invention comprises a rubber member and an organic fiber cord, and is characterized in that at least a part of the organic fiber cord is coated with the above - mentioned adhesive composition. Such a rubber - organic fiber cord composite of the present invention has excellent adhesion between the rubber and the organic fiber cord. Further, since the adhesive composition is used in the rubber - organic fiber cord composite, the environmental load is small.

[0046] In the rubber - organic fiber cord composite, the adhesive composition only needs to cover at least a part of the organic fiber cord, but from the viewpoint of further improving the adhesion between the rubber and the organic fiber cord, it is preferable that the adhesive composition coats the entire surface of the organic fiber cord. In addition, as a method for coating at least a part of the organic fiber cord with the above adhesive composition, it is not particularly limited, and examples include dipping, coating, spraying, etc. Further, when the above adhesive composition contains a solvent, the solvent can be removed by a drying treatment after coating.

[0047] The material of the organic fiber cord is not particularly limited and can be appropriately selected according to the application. Examples of the organic fiber cord include a fiber cord made of a polyester such as polyethylene terephthalate (PET), a fiber cord made of an aliphatic polyamide such as 6-nylon, 6,6-nylon, 4,6-nylon, a fiber cord made of polyketone, a fiber cord made of an aromatic polyamide such as para-phenylene terephthalamide, and a cellulose-based fiber cord such as rayon.

[0048] The form of the organic fiber cord is not particularly limited, and a monofilament or an organic fiber cord formed by twisting a plurality of single fiber filaments can be used. In this case, the average diameter of the single fiber filament is preferably 2 μm or more, more preferably 15 μm or more, and preferably 50 μm or less from the viewpoint of providing sufficiently high reinforcing properties to the rubber article. Also, the form of the organic fiber cord may be in a curtain shape.

[0049] In the rubber-organic fiber cord composite of the present invention, the organic fiber cord may be treated with a solution containing an isocyanate compound and / or an epoxy compound as a pretreatment for coating with the above adhesive composition. Note that a treatment form in which the organic fiber cord is directly treated with the above adhesive composition without performing a pretreatment on the organic fiber cord may be referred to as a "one-bath treatment", while a treatment form in which the organic fiber cord is treated with the above adhesive composition after performing a pretreatment on the organic fiber cord may be referred to as a "two-bath treatment".

[0050] Here, as the isocyanate compound used in the pretreatment solution, the same isocyanate compounds that can be contained in the above-described adhesive composition can be used. The isocyanate compound has an effect of promoting adhesion to the organic fiber cord which is the adherend of the adhesive composition. The content of the isocyanate compound in the pretreatment solution is not particularly limited, but as a solid content ratio, a range of more than 5% by mass and 95% by mass or less is preferable, a range of 15% by mass or more and 85% by mass or less is more preferable, and a range of 15% by mass or more and 70% by mass or less is even more preferable. If the content of the isocyanate compound is more than 5% by mass, the strength and chemical resistance of the adhesive layer composed of the adhesive composition are improved, and the adhesion and adhesiveness to the organic fiber cord are also improved. Further, if the content of the isocyanate compound is 95% by mass or less, the cohesive failure resistance of the adhesive layer at high temperature can be sufficiently ensured, and the adhesive strength at high temperature is also sufficient.

[0051] In addition, as the epoxy compound used in the above-described pretreatment solution, various compounds having at least one epoxy group in one molecule can be used. The epoxy compound acts as a crosslinking agent for the above-described adhesive composition and has excellent adhesiveness, heat resistance, durability, strength, flexibility, electrical insulation, etc.

[0052] The epoxy compound is not particularly limited, but is preferably a compound having two or more epoxy groups in one molecule, and more preferably a compound having four or more epoxy groups. When the epoxy compound has two or more epoxy groups in one molecule, the compound effectively functions as a crosslinking agent by the epoxy groups, and when it has four or more epoxy groups, crosslinking is performed more densely and flexibility is also imparted. In addition, the epoxy compound is not particularly limited, but preferably has 10 or less epoxy groups in one molecule. In this case, the crosslinking density does not become excessive, and toughness is also provided.

[0053] As the epoxy compound, specifically, reaction products of polyhydric alcohols such as diethylene glycol diglycidyl ether, polyethylene diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6 - hexanediol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether and epichlorohydrin can be mentioned. When these compounds are used as the epoxy compound, the adhesiveness between the organic fiber cord and the rubber can be further improved.

[0054] The content of the epoxy compound in the above - mentioned solution for pretreatment is not particularly limited, but as a ratio of solid content, a range of more than 5% by mass and 95% by mass or less is preferable, a range of 15% by mass or more and 85% by mass or less is more preferable, and a range of 15% by mass or more and 50% by mass or less is even more preferable. If it is contained more than 5% by mass, cross - linking by the epoxy resin is more formed in the adhesive layer composed of the adhesive composition, the cohesive failure resistance and adhesive strength at high temperature are more improved, and flexibility is also more imparted. Also, if it is 95% by mass or less, the resin cross - linking formed in the adhesive layer is sufficient and toughness is also provided.

[0055] As the rubber member of the rubber - organic fiber cord composite of the present invention, various rubber compositions (raw materials) containing at least a rubber component can be used, and it is preferable to form the rubber member from a vulcanized rubber obtained by vulcanizing the rubber composition. The rubber composition can be produced, for example, by blending a filler such as carbon black or silica, a cross - linking agent such as sulfur or peroxide, a cross - linking accelerator, etc. with a rubber component composed of natural rubber or synthetic rubber (butadiene rubber, styrene - butadiene rubber, isoprene rubber, etc.), and kneading, heating, extruding, etc.

[0056] The rubber-organic fiber cord composite of the present invention can be manufactured, for example, by coating at least a part of the organic fiber cord with the above adhesive composition, coating the organic fiber cord coated with the adhesive composition with an unvulcanized rubber composition that is the raw material of the rubber member to produce an unvulcanized rubber-organic fiber cord composite, and then vulcanizing it.

[0057] <Tire> The tire of the present invention is characterized by comprising the above rubber-organic fiber cord composite. The tire of the present invention has excellent adhesiveness between the rubber and the organic fiber cord. Further, since the tire uses a rubber-organic fiber cord composite treated with the adhesive composition, the environmental load is small. Here, in the tire of the present invention, the rubber-organic fiber cord composite can be used, for example, as a belt peripheral reinforcing layer such as a carcass, a belt, a belt reinforcing layer, or a flipper.

[0058] The tire of the present invention may be obtained by molding with an unvulcanized rubber composition and then vulcanizing according to the type of tire to be applied, or may be obtained by molding with a semi-vulcanized rubber that has undergone a pre-vulcanization process or the like and then further fully vulcanizing. In the tire of the present invention, an organic fiber cord treated with the above adhesive composition is used at any location of the tire, but other members are not particularly limited, and known members can be used. Further, the tire of the present invention is preferably a pneumatic tire, and as the gas filled in the pneumatic tire, in addition to normal air or air with adjusted oxygen partial pressure, inert gases such as nitrogen, argon, and helium can be used.

Examples

[0059] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples at all.

[0060] <Preparation of Adhesive Composition> An adhesive composition was prepared according to the formulation shown in Table 1. Specifically, to water, a 1N aqueous sodium hydroxide solution, polyphenols, and formalin (a solution obtained by diluting a 37% formaldehyde aqueous solution manufactured by Kanto Chemical Co., Inc. tenfold) were added and dissolved, and the mixture was stirred at 25°C for 2.5 hours to obtain a polyphenols / formaldehyde resin-containing solution. When adding polyphenols or formalin, an aqueous ammonia solution was added as necessary. To the obtained polyphenols / formaldehyde resin-containing solution, a latex of vinylpyridine-styrene-butadiene copolymer rubber was added, and the mixture was aged at 27°C for 24 hours to prepare an adhesive composition. Details of each component used are shown in Table 2. In addition, the obtained adhesive composition was evaluated for adhesiveness by the following method.

[0061] <Adhesiveness evaluation method 1 (one-bath treatment: Examples 1 to 7)> A 66 nylon cord for tires (66Ny, cord structure: 1400 dtex / 2 / 3) was treated with the above adhesive composition, and then embedded in an unvulcanized rubber composition containing a rubber component composed of natural rubber and styrene-butadiene copolymer, carbon black, and a crosslinking agent to prepare a rubber-organic fiber cord composite. Further, it was vulcanized at 160°C for 20 minutes under a pressure of 20 kgf / cm 2 2. The obtained vulcanizate was cooled to room temperature, the cord was dug out from the vulcanizate, and the resistance force (N / cord) when peeling the cord from the vulcanizate at a speed of 30 cm / min was measured at a room temperature atmosphere of 25 ± 1°C, and the adhesion state of the rubber was observed. The results are shown in Table 1. The evaluation criteria for the score of the rubber adhesion state in Table 1 are as shown in Table 3.

[0062] <Adhesiveness evaluation method 2 (two-bath treatment: Examples 8 to 10)> A polyethylene terephthalate cord for tires (PET, cord structure: 1670 dtex / 2) was pretreated with an aqueous solution containing 1% by mass of an epoxy compound (manufactured by Nagase ChemteX Corporation, trade name "Denacol EX614B"), 3% by mass of an isocyanate compound (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name "Elastron BN77"), and 6% by mass of isoban (manufactured by Kuraray Co., Ltd.) (first bath). After treating the pretreated PET cord with the above adhesive composition (second bath), it was embedded in an unvulcanized rubber composition containing natural rubber, a rubber component composed of a styrene-butadiene copolymer, carbon black, and a crosslinking agent to produce a rubber-organic fiber cord composite. Further, at 160 °C for 20 minutes under a pressure of 20 kgf / cm 2 It was vulcanized under pressure. The obtained vulcanizate was cooled to room temperature, the cord was dug out from the vulcanizate, and the resistance force (N / cord) when peeling the cord from the vulcanizate at a speed of 30 cm / min was measured at a room temperature atmosphere temperature of 25 ± 1 °C, and the adhesion state of the rubber was observed. The results are shown in Table 1. The evaluation criteria for the score of the rubber adhesion state in Table 1 are as shown in Table 3.

[0063]

Table 1

[0064]

Table 2

[0065]

Table 3

[0066] From Table 1, it can be seen that by treating the organic fiber cord with the adhesive composition of the present invention, the adhesiveness between the cord and the rubber can be sufficiently increased.

Industrial Applicability

[0067] According to the present invention, it is possible to provide an adhesive composition capable of achieving excellent adhesiveness even when resorcinol is not contained. Further, according to the present invention, it is possible to provide a rubber-organic fiber cord composite and a tire that have a small environmental load and excellent adhesiveness between the rubber and the organic fiber cord.

Claims

**Claim 1**: A pressure-sensitive adhesive composition comprising phloroglucinol, formaldehyde, and rubber latex, wherein the content of the rubber latex is 84.1 to 95% by mass in terms of solid content. **Claim 2** The pressure-sensitive adhesive composition according to claim 1, further comprising an isocyanate compound. **Claim 3** The pressure-sensitive adhesive composition according to claim 2, wherein the isocyanate compound is an aromatic compound containing (blocked) isocyanate groups. **Claim 4** The pressure-sensitive adhesive composition according to claim 1, wherein the rubber latex 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 rubber (NBR), and vinyl pyridine-styrene-butadiene copolymer rubber (Vp). **Claim 5** The pressure-sensitive adhesive composition according to any one of claims 1 to 4, which is a pressure-sensitive adhesive composition for organic fiber cords. **Claim 6** A rubber-organic fiber cord composite comprising a rubber member and an organic fiber cord, wherein at least a part of the organic fiber cord is coated with the pressure-sensitive adhesive composition according to any one of claims 1 to 5. **Claim 7** A tire comprising the rubber-organic fiber cord composite according to claim 6.

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