JP2017082069A - Resin composition and manufacturing method therefor, rubber composition containing resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for an adhesive used for a rubber product reinforced by a reinforcer and used in a processing process of a rubber and capable effectively being dispersed during mixing with the rubber by sufficiently reducing the softening point of the resin composition to a level without blocking.SOLUTION: It is found that a cashew nut shell liquid can specifically be used as a softening agent of a co-condensed resin for an adhesive used in a processing process of a rubber and further that the softening point of the resulting resin composition is effectively reduced by use thereof.SELECTED DRAWING: None

Description

  The present invention relates to an improvement in a resin composition obtained from an alkylphenol or the like.

  In rubber products such as tires, belts, hoses, and the like that need to be reinforced with reinforcing materials such as steel cords and organic fibers, strong adhesion between the rubber and the reinforcing material is required. In order to bond with rubber, a method of treating a reinforcing material with various adhesives and a method of blending an adhesive together with other various compounding agents in a rubber processing step are known. Among these, a method of blending an adhesive in the rubber processing step is widely adopted because it can be firmly vulcanized and bonded regardless of whether or not the reinforcing material is treated with an adhesive. As an adhesive used in such a rubber processing step, p-tert-octylphenol or p-nonylphenol is reacted with formalin to obtain a cocondensate, and the cocondensate obtained by reacting resorcin with the cocondensate ( For example, Patent Document 1), co-condensates obtained by reacting p-tert-butylphenol and o-phenylphenol with formalins to obtain a co-condensate, and reacting resorcin with the co-condensate (for example, Patent Document 2) It has been known.

  On the other hand, the adhesive used in the rubber processing step is required to be softened in the rubber processing step. For example, in the tire rubber field where phenolic resins are often used as an adhesive, it is known that the rubber processing step is usually performed at around 170 ° C. (for example, Non-Patent Document 1). Therefore, the resin used as an adhesive used in the rubber processing step must have a softening point sufficiently lower than the maximum temperature during rubber processing and 150 ° C. or less. Furthermore, from the viewpoint of improving the dispersibility during use of the resin, it is preferable that the softening point is as low as possible so that the resin does not block during storage.

JP-A-6-234824 JP-A-2015-52097

Japan Rubber Association Paper Vol. 73 (2000), no. 9, p488-493

  The present invention is a resin composition for an adhesive used in a rubber product reinforced with a reinforcing material and used in a rubber processing step, and sufficiently lowers the softening point of the resin composition so as not to block. Thus, an object of the present invention is to provide a resin composition that can be efficiently dispersed during kneading with rubber, and a method for producing the same.

  As a result of diligent investigations aimed at solving the problems, the present inventors have used a process oil usually used for rubber processing as a softening agent. Separation of the resin layer and the oil layer occurs, the effect as a softening agent cannot be sufficiently obtained, and furthermore, the resin composition causes blocking due to poor compatibility, making it difficult to produce industrially. While finding that problems may arise, cashew nut shell liquid can be used specifically as a softening agent for the co-condensation resin, and further, its use effectively reduces the softening point of the resulting resin composition. It has been found that by lowering to a low level, dispersibility in rubber during kneading can be improved, and at the same time blocking during storage can be avoided. Specifically, the following invention is included.

[1]
The following general formula (1)

（Ｒは分岐を有しても良いアルキル基またはフェニル基を表す。）
で表されるフェノール類、レゾルシン及びホルムアルデヒド由来の構成単位を有する共縮合樹脂及びカシューナッツシェル液を含む樹脂組成物。

(R represents an alkyl group or a phenyl group which may have a branch.)
The resin composition containing the co-condensation resin which has the structural unit derived from phenols, resorcinol, and formaldehyde represented by these, and cashew nut shell liquid.

[2]
The resin composition according to [1], wherein the content of the cashew nut shell liquid in the resin composition is 5 to 40% by weight.

[3]
[1] or [2], wherein the phenol represented by the general formula (1) is at least one selected from the group consisting of p-tert-butylphenol, o-phenylphenol, p-tert-octylphenol, and cresol. Resin composition.

[4]
The resin composition according to any one of [1] to [3], wherein the phenols represented by the general formula (1) are p-tert-butylphenol and o-phenylphenol.

[5]
The process for producing a resin composition according to any one of [1] to [4], comprising the steps (I) to (III) in this order.
(I) A step of obtaining a phenol resin by reacting one or more phenols represented by the general formula (1) with formaldehyde in the presence of an alkali.
(II) A step of reacting the phenolic resin with resorcin to obtain a cocondensation resin having structural units derived from phenols, resorcin and formaldehyde represented by the general formula (1).
(III) A step of mixing the co-condensation resin and cashew nut shell liquid.

[6]
The process for producing a resin composition according to [5], wherein the steps (II) and (III) are performed at 150 ° C. or lower.

[7]
[1] to [4] A rubber composition comprising the resin composition according to any one of [1] to [4].

  According to the present invention, it is possible to sufficiently reduce the softening point of a resin composition for an adhesive used in a rubber product reinforced with a reinforcing material and not used in a rubber processing step. When kneading, the resin composition is efficiently dispersed in the rubber. As a result, it is possible to provide a resin composition capable of strengthening the adhesion between the rubber and the reinforcing material. In addition, since the softening point of the resin composition of the present invention is significantly lower than 150 ° C., the kneaded product at the end of rubber kneading is added to the blending in which the temperature of the kneaded product at the end of rubber kneading is about 170 ° C. Since the compounding at a lower temperature is possible, the timing of compounding the resin composition at the time of preparing the rubber composition becomes more flexible.

<Cocondensation resin contained in the resin composition of the present invention>
Hereinafter, the present invention will be described in detail. The cocondensation resin contained in the resin composition of the present invention has the following formula (2) in the main chain.

（Ｒは分岐を有しても良いアルキル基またはフェニル基を表す。）
で示されるフェノール類由来の構成単位、以下式（３）

(R represents an alkyl group or a phenyl group which may have a branch.)
A structural unit derived from phenols represented by the following formula (3)

で示されるレゾルシン由来の構成単位およびホルムアルデヒド由来の構成単位を必ず含んでいることを特徴とする。なお、これら構成単位は通常、共縮合樹脂主鎖中に含まれるが、側鎖中に含まれる場合もある。

And a structural unit derived from resorcin and a structural unit derived from formaldehyde. These structural units are usually contained in the co-condensation resin main chain, but may be contained in the side chain.

  Among these structural units, as the structural unit derived from the phenols represented by the above formula (2), for example, the substituent R in the above formula (2) may have a branched alkyl group having 1 to 12 carbon atoms or A phenyl group is exemplified, and a methyl group, a tert-butyl group, a tert-octyl group, and a phenyl group are preferable from the viewpoint of availability of raw materials. One or two or more of these phenol-derived structural units may be contained.

  Since some alkylphenols may be difficult to use industrially due to the laws and regulations of each country, the possibility of being subject to laws and regulations is low, and the softening point of the cocondensation resin itself is relatively low. More preferred is a cocondensation resin having a structural unit derived from two types of phenols, p-tert-butylphenol and o-phenylphenol. In the case of a cocondensation resin having a structural unit derived from two types of phenols, p-tert-butylphenol and o-phenylphenol, the ratio thereof is o with respect to 1 mol of the structural unit derived from p-tert-butylphenol. -It is preferable to make the structural unit derived from phenylphenol into 0.5-6 times mole, and it is more preferable to set it as 1.5-6 times mole. When the amount is more than 0.5 times mol, the softening point of the cocondensation resin itself becomes sufficiently low, and when the amount is 6 times mol or less, the cocondensation resin can be produced at a lower cost.

  As a ratio of these structural units, for example, the structural unit derived from resorcin is usually contained in an amount of 0.5 to 2.0 times mol with respect to 1 mol of the total amount of the structural units derived from phenols. By setting the content to 0.5 times mol or more, it becomes possible to improve the ability as an adhesive between the rubber and the reinforcing material used by mixing with rubber during kneading, and content of 2.0 times mol or less By making it into an amount, it can be easily produced industrially. Moreover, the structural unit derived from formaldehyde (methylene group and / or dimethylene ether group) is usually contained in an amount of 1 to 2 moles per mole of the total amount of the structural units derived from phenols. The production cost of the co-condensation resin can be reduced by including a formaldehyde-derived linking group at least 1 mol.

  The ratio of these structural units can be determined, for example, by analyzing the resin composition obtained in the present invention using NMR. Specifically, a method of analyzing the resin composition by NMR and determining the ratio from the integrated values and chemical shifts derived from each structural unit among the obtained analysis results is exemplified.

  In the cocondensation resin contained in the resin composition of the present invention, a constituent unit other than the constituent units described above can be included as necessary. Examples of such structural units include structural units derived from various aldehydes, which are raw materials for cocondensation resins generally used as adhesives used in rubber processing steps.

  The softening point of the cocondensation resin contained in the resin composition of the present invention is usually 150 ° C. or lower, preferably 80 to 150 ° C., more preferably 80 to 140 ° C., and particularly 90 to 130 ° C. It is particularly preferred that By setting the softening point to 150 ° C. or lower, when mixing with a cashew nut shell liquid to obtain a resin composition, it becomes possible to mix with a sufficient amount of cashew nut shell liquid, and as a result, the softening point of the resin composition is sufficiently Can be reduced. Moreover, it becomes possible to reduce generation | occurrence | production of blocking more by making a softening point 80 degreeC or more.

<Resin composition of the present invention>
The cashew nut shell liquid (Cashew Nut Shell Liquid, hereinafter also referred to as CNSL) used in the present invention is a natural plant liquid obtained from cashew nut shells. Cashew nut shell liquid is a mixture composed of phenol derivatives having saturated or unsaturated hydrocarbon side chains. In particular, anacardic acid, cardanol, cardol (also referred to as curdle), and methyl cardol (also referred to as methyl curdle) are mainly included as its components. As a method for preparing the cashew nut shell liquid, there are a heating method and a solvent extraction method. Usually, an industrial cashew nut shell liquid is heated. Anacardic acid is decarboxylated by this heat treatment and converted to cardanol, so cardanol, cardol, and methyl cardol are the main components. Therefore, the composition ratio (wt% ) Are cardanol (75-85%), cardol (15-20%), methyl cardol (1-5%). In the present invention, the cashew nut shell liquid is obtained by appropriately purifying each component contained in the liquid by separating and purifying the cashew nut shell liquid, or by polymerizing a part of the cashew nut shell liquid without adding another component. Also included is a cashew nut shell polymer.

  As commercially available cashew nut shell liquid, for example, cashew liquid products (CNSL, LB-7000, LB-7250, CD-5L) manufactured by Tohoku Kako Co., Ltd., TAN HOA HOP PHAT Co. , Ltd. CNSL and the like. These cashew nut shell liquids may be used alone or in combination of two or more as required.

  The content of the cashew nut shell liquid in the resin composition of the present invention is usually 5 to 40% by weight, preferably 10 to 30% by weight, based on the total amount of the resin composition. By setting the content to 40% by weight or less, it becomes possible to reduce the blocking of the resin composition and the decrease in performance as an adhesive for rubber. By making the content 5% by weight or more, the softening point Is sufficiently exerted.

  Moreover, the resin composition of this invention may contain the softening agent compatible with the cocondensation resin contained in the resin composition of this invention other than cashew nut shell liquid as needed. As such a softening agent, for example, coumarone resin generally used in a rubber processing step is exemplified.

  The softening point of the resin composition of the present invention is, for example, 150 ° C. or less, preferably 80 ° C. to 140 ° C., particularly preferably 90 ° C. to 120 ° C. When the resin composition of the present invention is kneaded into rubber at a normal kneading temperature of about 170 ° C., a softening point of 150 ° C. or less is sufficient, but 100 to 100 for the purpose of suppressing resorcinol transpiration during kneading. When kneading at a low temperature of 130 ° C., the problem of poor dispersibility may occur unless the softening point is 120 ° C. or lower, which is lower than the kneading temperature. As a result, the performance as an adhesive between rubber and a reinforcing material It may not be fully expressed. On the other hand, if it is lower than 80 ° C., it may block during storage.

  The content of free resorcin contained in the resin composition of the present invention is preferably 8% by weight or less. By setting it to 8% by weight or less, it is possible to suppress transpiration of resorcin at the time of rubber kneading, which is preferable in terms of working environment.

  The total amount of phenols represented by the general formula (1), which is an unreacted monomer other than free resorcin, and the residual solvent used in the reaction, contained in the resin composition of the present invention is 5% by weight or less. Preferably, it is more preferably 3% by weight or less. By setting the amount to 5% by weight or less, the odor derived from the unreacted monomer and the residual solvent can be reduced, and the volatile organic compound is also reduced.

<The manufacturing method of the resin composition of this invention>
The resin composition of the present invention can be obtained by mixing a cocondensation resin having structural units derived from phenols, resorcin and formaldehyde represented by the general formula (1) and a cashew nut shell liquid. As the co-condensation resin, those produced by a known method such as Patent Document 1 (Japanese Patent Laid-Open No. 6-234824) and Patent Document 2 (Japanese Patent Laid-Open No. 2015-52097) can be used. In addition, when the cashew nut shell liquid is used in the same manner as a normal organic solvent in the production process of the cocondensation resin (reaction process of phenols, resorcin and formaldehyde represented by the general formula (1)), the cashew nut shell liquid is This may affect the reaction with phenols, resorcinol and formaldehyde represented by the general formula (1), or the physical properties of the resulting resin composition may change. In some cases, the rubber after vulcanization becomes unsuitable as an adhesive between the rubber and the reinforcing material.

  The co-condensation resin having a structural unit derived from phenols, resorcinol and formaldehyde represented by the general formula (1) and the cashew nut shell liquid are mixed with the co-condensation resin and the cashew nut shell obtained by the above-mentioned known methods. The co-condensation resin and the cashew nut shell liquid are heated to a temperature at which the co-condensation resin and the cashew nut shell liquid are sufficiently mixed (for example, 100 ° C. to 150 ° C.) and stirred as necessary. It is carried out by making it the state which was fully mixed. When carrying out the mixing operation, the container is brought to normal pressure or reduced pressure, and unreacted monomers (phenols, resorcin, formaldehyde represented by the above general formula (1)) and the solvent used in the reaction are contained in the cocondensation resin. It may be distilled off. Moreover, when obtaining the resin composition of this invention as solid, it obtains by cooling and solidifying the resin composition mixed as mentioned above.

  The resin composition of the present invention obtained as described above can be used as an adhesive between rubber and various reinforcing materials by kneading into the rubber composition. This is particularly effective in vulcanization adhesion with a reinforcing material. Examples of the reinforcing material include organic fibers such as nylon, rayon, polyester, and aramid, and steel cords such as a brass-plated steel cord and a galvanized steel cord. In particular, it is particularly effective in vulcanization adhesion with a steel cord plated with brass. In addition, the resin composition of this invention can also be used for the use mentioned above individually or in mixture of 2 or more types of resin compositions as needed.

<Rubber composition containing the resin composition of the present invention>
Then, the rubber composition containing the resin composition of this invention is explained in full detail.

  The rubber composition of the present invention is obtained by kneading the above-described resin composition of the present invention, a rubber component, a filler, and sulfur. It is preferable to knead a vulcanization accelerator, zinc oxide, a methylene donor compound and an organic cobalt compound together with these.

  The resin composition of the present invention is usually used in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the rubber component. Among these, the range of 1 to 5 parts by weight is preferable. When the amount is less than 0.5 parts by weight, it does not function usefully as an adhesive between the reinforcing material and the rubber. When the amount is more than 10 parts by weight, there is no problem with the above effect, but an effect commensurate with the amount of addition does not appear and is economically preferable. Absent.

  The rubber components used in the present invention include natural rubber, epoxidized natural rubber, deproteinized natural rubber and other modified natural rubber, as well as polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), polybutadiene. Various synthetic rubbers such as rubber (BR), acrylonitrile / butadiene copolymer rubber (NBR), isoprene / isobutylene copolymer rubber (IIR), ethylene / propylene-diene copolymer rubber (EPDM), halogenated butyl rubber (HR), etc. Illustrative examples include highly unsaturated rubbers such as natural rubber, styrene / butadiene copolymer rubber, and polybutadiene rubber. Particularly preferred is natural rubber. It is also effective to combine several rubber components such as a combination of natural rubber and styrene / butadiene copolymer rubber, a combination of natural rubber and polybutadiene rubber.

  Examples of natural rubber include natural rubber of grades such as RSS # 1, RSS # 3, TSR20, SIR20 and the like. As the epoxidized natural rubber, those having a degree of epoxidation of 10 to 60 mol% are preferable, and examples thereof include ENR25 and ENR50 manufactured by Kumpoulan Guthrie. As the deproteinized natural rubber, a deproteinized natural rubber having a total nitrogen content of 0.3% by weight or less is preferable. The modified natural rubber contains a polar group obtained by reacting natural rubber with 4-vinylpyridine, N, N, -dialkylaminoethyl acrylate (for example, N, N, -diethylaminoethyl acrylate), 2-hydroxyacrylate, or the like in advance. Natural rubber is preferably used.

  Examples of the SBR include emulsion polymerization SBR and solution polymerization SBR described in pages 210 to 211 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. In particular, solution polymerization SBR is preferably used, and further, solution polymerization SBR, JSR in which molecular ends are modified with 4,4′-bis- (dialkylamino) benzophenone such as “Nippol (registered trademark) NS116” manufactured by Nippon Zeon Co., Ltd. Solution polymerized SBR having a molecular end modified with a tin halide compound such as “SL574” manufactured by the company, commercially available silane-modified solution polymerized SBR such as “E10” and “E15” manufactured by Asahi Kasei Corporation, lactam compounds, amide compounds, A urea compound, an N, N-dialkylacrylamide compound, an isocyanate compound, an imide compound, a silane compound having an alkoxy group (trialkoxysilane compound, etc.), an aminosilane compound alone, or a tin compound and an alkoxy group Silane compounds with alkyl and alkyl acrylamide compounds And silane compound having an alkoxy group or the like, and using two or more different compounds described above and modifying the molecular terminals, respectively, nitrogen, tin, silicon, or a plurality of these elements A solution-polymerized SBR having the following is particularly preferably used.

  Examples of BR include solution polymerization BR such as high cis BR having 90% or more of cis 1,4 bond and low cis BR having cis bond of around 35%, and low cis BR having a high vinyl content is preferably used. . Furthermore, tin-modified BR such as “Nipol (registered trademark) BR 1250H” manufactured by Nippon Zeon, 4,4′-bis- (dialkylamino) benzophenone, tin halide compound, lactam compound, amide compound, urea compound, N, An N-dialkylacrylamide compound, an isocyanate compound, an imide compound, a silane compound having an alkoxy group (trialkoxysilane compound, etc.), an aminosilane compound alone, or a silane compound having a tin compound and an alkoxy group, Using two or more different compounds as described above, such as an alkylacrylamide compound and a silane compound having an alkoxy group, each of the molecular ends obtained by modifying the molecular ends is either nitrogen, tin, or silicon, or those Solution polymerization B with multiple elements But particularly preferably used. These BRs are usually used in blends with natural rubber.

  The rubber component described above is preferably natural rubber, and the proportion of natural rubber in the rubber component is preferably 70% by weight or more.

  Examples of the filler used in the present invention include carbon black, silica, talc, clay, aluminum hydroxide, titanium oxide and the like which are usually used in the rubber field. These fillers are used alone or as necessary. Two or more kinds may be mixed and used. As these fillers, carbon black and silica are preferably used, and carbon black is more preferably used. In particular, the proportion of carbon black in the filler is preferably 70% by weight or more.

Examples of the carbon black include those described on page 494 of the “Rubber Industry Handbook <Fourth Edition” edited by the Japan Rubber Association. ), FEF (Fast Extraction Furnace), MAF, GPF (General Purpose Furnace), SRF (Semi-Reinforming Furnace) and the like are preferable. The rubber composition for a tire tread CTAB surface 40~250m ² / g, nitrogen adsorption specific surface area 20 to 200 m ² / g, carbon black having a particle diameter 10~50nm is preferably used, with CTAB surface 70~180m ² / g A certain carbon black is more preferable, and examples thereof include N110, N220, N234, N299, N326, N330, N330T, N339, N343, N351 and the like in the ASTM standard. A surface-treated carbon black in which 0.1 to 50% by weight of silica is attached to the surface of the carbon black is also preferable. Furthermore, it is also effective to combine several kinds of fillers such as a combination of carbon black and silica.

Examples of the silica include silica having a CTAB specific surface area of 50 to 180 m ² / g and a nitrogen adsorption specific surface area of 50 to 300 m ² / g. “AQ”, “AQ-N” manufactured by Tosoh Silica Co., Ltd., Degussa "Ultrasil (registered trademark) VN3", "Ultrasil (registered trademark) 360", "Ultrasil (registered trademark) 7000" manufactured by Rhodia, "Zeosil (registered trademark) 115GR", "Zeosil (registered trademark) 1115MP" manufactured by Rhodia , “Zeosil (registered trademark) 1205MP”, “Zeosil (registered trademark) Z85MP”, “Nippal (registered trademark) AQ” manufactured by Nippon Silica Co., Ltd., and the like are preferably used. When silica is usually used as a filler, bis (3-triethoxysilylpropyl) tetrasulfide ("Si-69" manufactured by Degussa) or bis (3-triethoxysilylpropyl) disulfide ("Si-" manufactured by Degussa) 75 "), bis (3-diethoxymethylsilylpropyl) tetrasulfide, bis (3-diethoxymethylsilylpropyl) disulfide, octanethioic acid S- [3- (triethoxysilyl) propyl] ester (General Electronic Silicones) It is preferable to add a compound having an element such as silicon that can be bonded to silica or a functional group such as alkoxysilane, such as one or more silane coupling agents selected from the group consisting of “NXT silane” manufactured by the same manufacturer.

Examples of the aluminum hydroxide include aluminum hydroxide having a nitrogen adsorption specific surface area of 5 to 250 m ² / g and a DOP oil supply amount of 50 to 100 ml / 100 g.

  For example, the amount of the filler used is preferably in the range of 10 to 120 parts by weight per 100 parts by weight of the rubber component. Particularly preferred is 30 to 70 parts by weight.

  Examples of the sulfur component used in the present invention include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. Usually, powdered sulfur is preferred, and insoluble sulfur is preferred when used for tire members having a large amount of sulfur such as tire belt members. Although the usage-amount of a sulfur component is not specifically limited, The range of 1-10 weight part per 100 weight part of rubber components is preferable. The range of 5 to 10 parts by weight is preferable for tire belt members and the like.

  Examples of vulcanization accelerators used in the present invention include thiazole series described on pages 412 to 413 of Rubber Industry Handbook <Fourth Edition> (issued by the Japan Rubber Association on January 20, 1994). Examples include vulcanization accelerators, sulfenamide vulcanization accelerators, and guanidine vulcanization accelerators.

Specifically, for example, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS),
N, N-dicyclohexyl-2-benzothiazolesulfenamide (DCBS), 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), diphenylguanidine (DPG) can be mentioned. Among them, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS), N, N-dicyclohexyl-2-benzothiazolesulfenamide ( DCBS) or dibenzothiazyl disulfide (MBTS) and diphenylguanidine (DPG) are preferably used in combination.

  As a usage-amount of a vulcanization accelerator, the range of 0.5-3 weight part per 100 weight part of rubber components is preferable, for example. In particular, the range of 0.5 to 1.2 parts by weight is particularly preferable.

  For example, the amount of zinc oxide used is preferably in the range of 3 to 15 parts by weight per 100 parts by weight of the rubber component. Among these, the range of 5 to 10 parts by weight is particularly preferable.

  Examples of methylene donor compounds used in the present invention include those usually used in the rubber industry such as hexamethylenetetramine, hexakis (methoxymethyl) melamine, pentakis (methoxymethyl) methylolmelamine, tetrakis (methoxymethyl) dimethylolmelamine Can be mentioned. Among them, hexakis (methoxymethyl) melamine alone or a mixture containing it as a main component is preferable. These formaldehyde generators can be used alone or in combination, and the blending amount thereof is preferably in the range of about 0.5 to 4 parts by weight with respect to 100 parts by weight of the rubber component, and 1 to 3 parts by weight. A range of the degree is more preferable.

  Examples of the organic cobalt compound used in the present invention include acid cobalt salts such as cobalt naphthenate and cobalt stearate, and fatty acid cobalt / boron complex compounds (for example, trade name “Manobond C (registered trademark)” manufactured by Rhodia). Etc. The amount of the organic cobalt compound used is preferably in the range of 0.05 to 0.4 parts by weight in terms of cobalt content with respect to 100 parts by weight of the rubber component.

  The rubber composition of the present invention can be compounded with various compounding agents conventionally used in the rubber field and kneaded. Examples of such compounding agents include anti-aging agents, oils, retarders, peptizers, and stearic acid.

  Examples of the anti-aging agent include those described in pages 436 to 443 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. Among them, N-phenyl-N′-1,3-dimethylbutyl-p-phenylenediamine (6PPD), reaction product of aniline and acetone (TMDQ), poly (2,2,4-trimethyl-1,2-) dihydro Quinoline) (“Antioxidant FR” manufactured by Matsubara Sangyo Co., Ltd.), synthetic wax (paraffin wax, etc.) and vegetable wax are preferably used.

  Examples of the oil include process oil and vegetable oil. Examples of the process oil include paraffinic process oil, naphthenic process oil, and aromatic process oil.

  Examples of the retarder include phthalic anhydride, benzoic acid, salicylic acid, N-nitrosodiphenylamine, N- (cyclohexylthio) -phthalimide (CTP), sulfonamide derivatives, diphenylurea, bis (tridecyl) pentaerythritol-diphosphite, etc. N- (cyclohexylthio) -phthalimide (CTP) is preferably used.

<The manufacturing method of the rubber composition containing the resin composition of this invention>
The rubber composition containing the resin composition of the present invention can be obtained, for example, by the following method.

(A) Step of kneading filler and rubber component Kneading of the filler and rubber component can be performed using a closed kneading apparatus such as a Banbury mixer. Such kneading usually involves heat generation, and the temperature at the end of kneading is preferably in the range of 140 ° C. to 180 ° C., more preferably in the range of 150 ° C. to 170 ° C. The kneading time is about 5 to 10 minutes.

(B) The step of kneading the kneaded product obtained in step A, the sulfur component and the vulcanization accelerator The kneaded product obtained in step A, the sulfur component and the vulcanization accelerator are kneaded, for example, in a sealed manner such as a Banbury mixer It can be performed using a kneading apparatus or an open roll. The temperature of the kneaded product at the end of kneading is preferably 30 ° C to 100 ° C, and more preferably 60 ° C to 90 ° C. The kneading time is usually about 5 to 10 minutes.

  Since the resin composition of the present invention has a low softening point, it can be added in the step (A) or (B), but it is preferably added in the step (A).

  When using zinc oxide, an antioxidant, oil, fatty acids, and peptizer, these are preferably added in the step (A).

When using a retarder, it is preferable to add at the process of (B).

  The rubber composition containing the resin composition of the present invention thus obtained is particularly effective in vulcanization adhesion with a reinforcing material. Examples of the reinforcing material include organic fibers such as nylon, rayon, polyester, and aramid, and steel cords such as a brass-plated steel cord and a galvanized steel cord. In particular, it is particularly effective in vulcanization adhesion with a steel cord plated with brass.

  A rubber composition containing the resin composition of the present invention is molded together with a reinforcing material, and a rubber product in which the rubber and the reinforcing material are firmly bonded can be obtained through a vulcanization process. The vulcanization step is preferably performed at 120 ° C to 180 ° C. The vulcanization step is performed at normal pressure or under pressure.

  Hereinafter, the present invention will be described more specifically by showing examples and comparative examples. The present invention is not limited by these examples. Unless otherwise specified, the content of each component, the amount of residual solvent, and the amount of free monomer described in the Production Examples, Examples and Comparative Examples below are resins containing the obtained cocondensation resin or cashew nut shell liquid. % By weight of the substance relative to the total amount in the composition.

Analysis and performance evaluation of the co-condensation resin and the resin composition were performed as follows.
[1] Measurement of average molecular weight of resin The average molecular weight of the cocondensation resin and the resin composition was calculated as a weight average molecular weight in terms of polystyrene by gel permeation chromatography (GPC).
Equipment used: HLC-8220GPC (manufactured by Tosoh Corporation)
Column: TSK guard column SUPER HZ-L (manufactured by Tosoh)
+ TSK-GEL SUPER HZ1000 (4.6 mmφ × 150 mm)
+ TSK-GEL SUPER HZ2500 (4.6mmφ × 150mm)
+ TSK-GEL SUPER HZ4000 (4.6 mmφ × 150 mm)
Column temperature: 40 ° C
Injection volume: 10 μL
Carrier and flow rate: Tetrahydrofuran 0.35 mL / min
Sample preparation: About 0.02 g of the cocondensation resin or resin composition of the present invention is dissolved in 20 mL of tetrahydrofuran.

[2] Measurement of free monomer and residual solvent The free monomer content and the residual solvent content were determined by gas chromatography based on the following conditions.
Equipment used: Gas chromatograph GC-14B manufactured by Shimadzu Corporation
Column: Glass column outer diameter 5 mm x inner diameter 3.2 mm x length 3.1 m
Filler: Filler Silicone OV-17 10% Chromosorb WHP 80/100 mesh, max. temp. 340 ° C
Column temperature: 80 ° C → 280 ° C
Vaporization chamber temperature: 250 ° C
Detector temperature: 280 ° C
Detector: FID
Carrier: N ₂ (40 ml / min)
Combustion gas: Hydrogen (60 kPa), Air (60 kPa)
Injection volume: 2 μL
1 g of the cocondensation resin or resin composition of the present invention and 0.05 g of anisole as a standard were dissolved in 10 mL of acetone and analyzed under the above conditions. By the internal standard method (GC-IS method), the residual solvent and free monomer content (%) in the co-condensation resin or resin composition were quantified.

[3] Measurement of softening point Measured by a method based on JIS-K2207.

<Production Example 1>
“Synthesis of co-condensation resin containing structural units derived from p-tert-butylphenol, o-phenylphenol and resorcin”
In a four-necked separable flask equipped with a reflux condenser and a thermometer, 360.0 g (4.44 mol) of formalin having a purity of 37%, 60.0 g (0.40 mol) of p-tert-butylphenol, o-phenylphenol 340 0.0 g (2.00 mol) was added in order. Thereafter, the temperature was raised to 40 ° C., 120.0 g (0.72 mol) of a 24% aqueous sodium hydroxide solution was added, and the mixture was stirred until the exotherm subsided. After confirming that the exotherm had subsided, the temperature was raised to an internal temperature of 65 ° C., and the reaction was carried out at the same temperature for 2 hours.
After completion of the reaction, 105.9 g (0.32 mol) of 30% sulfuric acid and 4.53 (0.036 mol) of oxalic acid dihydrate were added and stirred for 0.2 hours, and then 50.0 g of sodium sulfate was added for 0.2 hours. The mixture was allowed to stand after stirring, and the aqueous layer was removed.
Subsequently, 369.6 g (3.36 mol) of resorcin was added, the temperature was raised to an internal temperature of 110 ° C., and dehydration was performed for 2 hours under slightly reduced pressure (92 kPa). During this time, the internal temperature rose from 115 ° C to 118 ° C. Subsequently, the internal temperature was raised to 125 ° C. and dehydration (92 kPa) was performed for 1 hour. Subsequently, the internal temperature was raised to 140 ° C. and dehydration (92 kPa) was performed for 1 hour. Then, it heated up to 145-150 degreeC of internal temperature, and water was distilled off by heat-retaining for 1 hour. Thereafter, the pressure was reduced to 16 kPa while maintaining the internal temperature at 140 to 150 ° C., and water was further distilled off to obtain 817 g of a brown cocondensation resin.
Average molecular weight of co-condensation resin: 2200, softening point: 125 ° C., free p-tert-butylphenol content: 0.0%, free o-phenylphenol content: 1.7%, free resorcin content: 7.9%.

<Example 1>
In a four-necked separable flask equipped with a reflux condenser and a thermometer, 160.0 g of the co-condensation resin obtained in Production Example 1, industrial cashew nut shell liquid (CNSL manufactured by TAN HOA HOP PHAT Co., Ltd.) (at room temperature) (Oil) 40.0 g was added in order. Thereafter, the temperature was raised to 140 ° C. and stirred for 1 hour while keeping the temperature at 140 to 150 ° C., and the co-condensation resin and the cashew nut shell liquid were mixed so as to be uniform. Thereafter, the product was taken out on a metal vat, cooled to room temperature, and crushed in a mortar to obtain 197.8 g of a brown resin composition containing a cashew nut shell liquid.
Average molecular weight of resin composition containing cashew nut shell liquid: 2060, softening point: 93 ° C., free p-tert-butylphenol: 0.0%, free o-phenylphenol: 1.1%, free resorcin: 6.5% Cashew nut shell content: 20%.

<Example 2>
A four-necked separable flask equipped with a reflux condenser and a thermometer was charged with 180.0 g (2.22 mol) of formalin having a purity of 37%, 30.0 g (0.20 mol) of p-tert-butylphenol, 170 of o-phenylphenol. 0.0 g (1.00 mol) was added in order. Thereafter, the internal temperature was raised to 40 ° C., 80.0 g (0.48 mol) of a 24% aqueous sodium hydroxide solution was added, and the mixture was stirred until the exotherm subsided. After confirming that the exotherm had subsided, the temperature was raised to an internal temperature of 65 ° C., and the reaction was carried out at the same temperature for 2 hours.
After completion of the reaction, 70.5 g (0.22 mol) of 30% sulfuric acid and 3.02 (0.024 mol) of oxalic acid dihydrate were added and stirred for 0.2 hours, and then 25.0 g of sodium sulfate was added and added for 0.2 hours. The mixture was allowed to stand after stirring, and the aqueous layer was removed.
Subsequently, 171.6 g (1.56 mol) of resorcin was added, the temperature was raised to an internal temperature of 110 ° C., and dehydration was performed for 2 hours under slightly reduced pressure (92 kPa). During this time, the internal temperature rose from 115 ° C to 118 ° C. Subsequently, the internal temperature was raised to 125 ° C. and dehydration (92 kPa) was performed for 1 hour. Subsequently, the internal temperature was raised to 140 ° C. and dehydration (92 kPa) was performed for 1 hour. Then, it heated up to 145-150 degreeC of internal temperature, and water was distilled off by heat-retaining for 1 hour.
Thereafter, 98.8 g of industrial cashew nut shell liquid (CNSL manufactured by TAN HOA HOP PHAT Co., Ltd.) (oil at normal temperature) was added, and the pressure was reduced to 16 kPa while maintaining the internal temperature at 140 to 150 ° C. to obtain a brown resin composition 493 g was obtained.
Average molecular weight of resin composition containing cashew nut shell liquid: 2231, softening point: 99 ° C., free p-tert-butylphenol content: 0.0%, free o-phenylphenol content: 1.3%, free resorcin content: 5 .6%, cashew nut shell liquid content: 20%.

<Production Example 2>
In Production Example 1, the reaction was conducted in the same manner as in Production Example 1 except that the reaction between phenols and formalin was 65 ° C. for 3 hours and the amount of resorcin used in the reaction with resorcin was 316.8 g (2.88 mol). And 769 g of brown cocondensation resin was obtained.
Average molecular weight of co-condensation resin: 3116, softening point: 142 ° C., free p-tert-butylphenol content: 0.0%, free o-phenylphenol content: 1.0%, free resorcin content: 5.0%.

<Example 3>
In a four-necked separable flask equipped with a reflux condenser and a thermometer, 160.0 g of the cocondensation resin obtained in Production Example 2, industrial cashew nut shell liquid (CNSL manufactured by TAN HOA HOP PHAT Co., Ltd.) (at room temperature) (Oil) 40.0 g was added in order. Then, it heated up to the internal temperature of 140 degreeC, and it mixed so that cocondensation resin and cashew nut shell liquid might become uniform by stirring for 1 hour, keeping at internal temperature 140-150 degreeC. Thereafter, the product was taken out on a metal vat, cooled to room temperature, and crushed in a mortar to obtain 199.0 g of a brown resin composition containing a cashew nut shell liquid.
Average molecular weight of resin composition containing cashew nut shell liquid: 2884, softening point: 109 ° C., free p-tert-butylphenol: 0.0%, free o-phenylphenol: 0.8%, free resorcin: 4.1% Cashew nut shell content: 20%.

<Example 4>
In a four-necked separable flask equipped with a reflux condenser and a thermometer, 135.0 g of the cocondensation resin obtained in Production Example 1, industrial cashew nut shell liquid (CNSL manufactured by TAN HOA HOP PHAT Co., Ltd.) (at room temperature) (Oil) 15.0 g was added in order. Then, it heated up to the internal temperature of 140 degreeC, and it mixed so that cocondensation resin and cashew nut shell liquid might become uniform by stirring for 1 hour, keeping at internal temperature 140-150 degreeC. Thereafter, the product was taken out on a metal vat, cooled to room temperature, and roughly crushed in a mortar to obtain 147.2 g of a brown resin composition containing a cashew nut shell liquid.
Average molecular weight of resin composition containing cashew nut shell liquid: 2077, softening point: 112 ° C., free p-tert-butylphenol: 0.0%, free o-phenylphenol: 1.2%, free resorcin: 7.2% Cashew nut shell liquid content: 10%.

<Example 5>
In a four-neck separable flask equipped with a reflux condenser and a thermometer, 85.1 g of the cocondensation resin obtained in Production Example 1, industrial cashew nut shell liquid (CNSL manufactured by TAN HOA HOP PHAT Co., Ltd.) (at room temperature) (Oil) 4.5 g was added in order. Then, it heated up to the internal temperature of 140 degreeC, and it mixed so that cocondensation resin and cashew nut shell liquid might become uniform by stirring for 1 hour, keeping at internal temperature 140-150 degreeC. Thereafter, the product was taken out on a metal vat, cooled to room temperature, and crushed in a mortar to obtain 88.3 g of a brown resin composition containing a cashew nut shell liquid.
Average molecular weight of resin composition containing cashew nut shell liquid: 2184, softening point: 120 ° C., free p-tert-butylphenol: 0.0%, free o-phenylphenol: 1.2%, free resorcin: 7.5% , Cashew nut shell content: 5%.

<Example 6>
In a four-necked separable flask equipped with a reflux condenser and a thermometer, 140.0 g of the cocondensation resin obtained in Production Example 2, industrial cashew nut shell liquid (CNSL manufactured by TAN HOA HOP PHAT Co., Ltd.) (at room temperature) (Oil) 60.0 g was added in order. Then, it heated up to the internal temperature of 140 degreeC, and it mixed so that cocondensation resin and cashew nut shell liquid might become uniform by stirring for 1 hour, keeping at internal temperature 140-150 degreeC. Thereafter, the product was taken out on a metal vat, cooled to room temperature, and crushed in a mortar to obtain 198 g of a brown resin composition containing a cashew nut shell liquid.
Average molecular weight of resin composition containing cashew nut shell liquid: 3187, softening point: 109 ° C., free p-tert-butylphenol: 0.0%, free o-phenylphenol: 0.7%, free resorcin: 3.6% Cashew nut shell liquid content: 30%.

<Comparative Example 1>
To a four-necked separable flask equipped with a reflux condenser and a thermometer, 45.0 g of the co-condensation resin obtained in Production Example 1 and 5.0 g of naphthenic process oil were sequentially added. Thereafter, the temperature was raised to an internal temperature of 140 ° C. and stirred for 2 hours while keeping the internal temperature at 140 to 150 ° C. However, the compatibility with the co-condensation resin was poor, and part of the process oil remained separated. Thereafter, the resin composition was taken out on a metal vat to obtain 49.5 g of a resin composition containing a separated naphthenic process oil. For analysis / evaluation, a separated oil-free portion was selected and used.
Average molecular weight of resin composition containing naphthenic process oil: 1898, softening point: 124 ° C., free p-tert-butylphenol: 0.0%, free o-phenylphenol: 1.5%, free resorcin: 7.3 %, Content of process oil (including separation part): 10%.

<Comparative example 2>
To a four-neck separable flask equipped with a reflux condenser and a thermometer, 45.0 g of the cocondensation resin obtained in Production Example 1 and 5.0 g of paraffinic process oil were sequentially added. Thereafter, the temperature was raised to an internal temperature of 140 ° C. and stirred for 2 hours while maintaining the internal temperature at 140 to 150 ° C. However, the compatibility with the co-condensation resin was poor and a part of the process oil remained separated. Thereafter, it was taken out on a metal vat and 49.2 g of a resin composition containing a separated paraffinic process oil was obtained. For analysis and evaluation, a portion without separated oil was selected and used.
Average molecular weight of resin composition containing paraffinic process oil: 1722, softening point: 123 ° C., free p-tert-butylphenol: 0.0%, free o-phenylphenol: 1.5%, free resorcin: 7.2 %, Content of process oil (including separation part): 10%.

<Comparative Example 3>
To the four-necked separable flask equipped with a reflux condenser and a thermometer, 160.0 g of the cocondensation resin obtained in Production Example 1 and 40.0 g of gum rosin were sequentially added. Thereafter, the temperature was raised to an internal temperature of 140 ° C., and the mixture was stirred for 2 hours while being kept at an internal temperature of 140 to 150 ° C. As a result, a transparent resin liquid was obtained. Thereafter, the resin composition was taken out on a metal bat and cooled to room temperature, and 196.9 g of a resin composition containing gum rosin, which was partially cloudy, was obtained.
Average molecular weight of resin composition containing gum rosin: 1425, softening point: 122 ° C., free p-tert-butylphenol: 0.0%, free o-phenylphenol: 1.3%, free resorcinol: 7.4%, gum rosin Content: 20%.

  Below, the composition of the resin composition obtained by the said Examples 1-6 and the comparative examples 1-3, the softening point, and the evaluation result of the uniformity and blocking property of resin are shown. The uniformity and blocking property of the resin were evaluated as follows.

<Uniformity of resin composition>
○: The compatibility of the co-condensation resin and the softening agent (cashew nut shell liquid, each oil or gum rosin) was good, and a uniform resin composition that was solid at room temperature was obtained.
X: The compatibility of the co-condensation resin and the softening agent was poor, and a uniform resin composition that was solid at room temperature could not be obtained.

<Blocking property of resin composition (inter-attachment)>
Each sample was pulverized into a fine powder, and about 5 g was weighed in a plastic bag with a chuck and allowed to stand in an oven at 40 ° C. and 95% RH for 1 to 3 days to confirm the state of the particles.
(Double-circle): There is no mutual attachment between grains by 3 days later. The powder form was retained.
○: Although it can be hardened by 3 days, it can be easily solved.
Δ: Some grains adhered to each other by 3 days later.
X: By one day, the grains were bonded together.

2. Production examples and physical property evaluation of rubber compositions using the resin compositions obtained in the above examples <Manufacture of unvulcanized rubber compositions containing the resin compositions obtained in the above examples>
As a resin adhesive, in order to compare the resin compositions produced in Examples 2, 3, 4 and 6 above, and the physical properties of the resin compositions, a conventional resin adhesive SUMIKANOL620 (Taoka Chemical Industries) was used. Co., Ltd.), a cocondensation resin produced in Production Example 2 that does not contain cashew nut shell liquid, and an unvulcanized rubber composition was produced by the following method without using a resin adhesive as a blank.

In accordance with the composition shown in Table 2 below, first, components other than insoluble sulfur, a vulcanization accelerator and a methylene donor were added and mixed with a pressure kneader made by Toshin, and discharged when the temperature reached 160 ° C. (Step A). Subsequently, insoluble sulfur, a vulcanization accelerator, and a methylene donor were added to and mixed with the obtained mixture with a 6-inch open roll made of Kansai Roll that was kept at 60 ° C. to prepare a rubber composition for coating a steel cord (Step B). ).
In Table 3 below, addition of the resin adhesive was indicated as A in Step A, and addition of B was indicated in Step B as B. Moreover, unless otherwise indicated, the numerical value of Table 2 below represents a mass part.

The origin of each component in Table 2 is as follows.
・ Natural rubber: SMR-CV60
Carbon black: “Seast 300” (HAF-LS grade) manufactured by Tokai Carbon Co., Ltd.
・ Zinc flower: 2 types of zinc flower manufactured by Shodo Chemical Industry Co., Ltd.
Anti-aging agent: “Antioxidant FR” manufactured by Matsubara Sangyo Co., Ltd.
・ Cobalt salt: Cobalt stearate (reagent)
Insoluble sulfur: “Cristex HS OT-20” manufactured by Flexis
・ Vulcanization accelerator: N, N-dicyclohexyl-2-benzothiazolesulfenamide (reagent)
・ Methylene donor: “Sumikanol 507AP” manufactured by Bara Chemical Co., Ltd.

<Rubber property test of unvulcanized rubber composition and vulcanized rubber composition>
After preparing the unvulcanized rubber composition obtained as described above and leaving it to stand at room temperature for 24 hours, it was heated with a 6-inch open roll made of Kansai roll kept at 60 ° C., made into a sheet, and left on a metal plate. Cooled to room temperature. Subsequently, using the unvulcanized sample, Mooney viscosity test (JIS K 6300-1: 2001 compliant, measured at 130 ° C., ML (1 + 4)) and rheometer test (JIS K 6300-2: 2001 compliant, 160 Measurement at ℃, MH, t10, t90) were carried out.
The unvulcanized sample was vulcanized under pressure at 160 ° C. and 6 MPa under the condition of t90 + 5 minutes to prepare a vulcanized rubber sheet having a thickness of 2 mm.
Next, using a rubber test piece prepared from the vulcanized rubber sheet, a tensile test (based on JIS K 6251: 2010, measuring tensile stress M200, breaking strength Tb and breaking elongation Eb at 25 ° C.), resin dispersibility (determination) Criteria: Visually check whether there is any solid foreign matter on the surface of the tensile test specimen.No foreign matter: ○, foreign matter present: x), and hardness measurement (conforms to JIS K 6253: 2006, measured at 25 ° C.) ). In this test result, the rubber composition to which no resin composition was added (Comparative Example 4) was taken as 100, and each was evaluated relatively. The results are shown in Table 3.

  As shown in Table 3 above, the rubber composition containing the resin compositions obtained in Examples 2, 3, 4 and 6 is a known resin adhesion as a result of the unvulcanized rubber physical property test and the vulcanized rubber physical property test. The performance equivalent to that of the agent “SUMIKANOL620” was shown, and it was confirmed that each physical property was improved as compared with the rubber composition to which no resin composition was added.

  Further, the resin composition of the present invention can be added in the step of kneading the filler and the rubber component (the above-mentioned step A), and is obtained in step A, which is performed at a lower temperature than step A. It was found that even when the kneaded product, the sulfur component, and the vulcanization accelerator were kneaded (step B above), the same performance as the known resin adhesive “SUMIKANOL 620” was exhibited (Example 9).

<Evaluation method and evaluation result of initial adhesiveness and wet heat adhesiveness of vulcanized rubber composition including resin compositions obtained in the above Examples, Production Examples and Comparative Examples>

  A rubber-steel cord composite sample was prepared using each of the unvulcanized rubber compositions obtained as described above. Specifically, a brass-plated steel cord (diameter of about 0.8 mm, 3 × 0.20 + 6 × 0.35 mm structure, brass plating of copper / zinc = 64/36 (mass ratio)) at intervals of 1/10 mm For the peel adhesion test, both sides of the array of five were coated with about 2 mm thick unvulcanized rubber sheets made of each of the above unvulcanized rubber compositions, and the cords were laminated in parallel. An unvulcanized sample was prepared. Using the obtained unvulcanized sample, initial adhesiveness and wet heat adhesiveness were evaluated by the following methods.

<Initial adhesiveness>
After preparing the above unvulcanized sample, it was allowed to stand at room temperature for 24 hours, then vulcanized under pressure at 160 ° C. and 6 MPa under conditions of t90 + 5 minutes, and a 1 cm × 1 cm × 6 cm rectangular parallelepiped with 1 cm of 5 steel cords sandwiched A piece of rubber was obtained. This rubber piece is subjected to a steel cord pull-out test for each piece using an autograph “AGC-X” manufactured by Shimadzu Corporation, and the stress at the time of pulling in the vertical direction at 100 mm / min is the rubber pulling strength (kgf ). Moreover, the rubber coverage of the steel cord after drawing was visually observed and evaluated at 0 to 100%. Measurement and evaluation were carried out at N = 10 (pieces), and an average value was obtained. The results are shown in Table 4 below.

  As shown in Table 4 above, when the cocondensation resin produced in Production Example 2 containing no cashew nut shell liquid is used as a resin adhesive, the tensile strength is inferior to that of Comparative Example 4 in which no resin adhesive is used. There was found. This result is presumed to be due to the fact that the cohesive force of the rubber composition is reduced and the performance as a resin adhesive is not exhibited.

<Wet heat adhesion (adhesion after wet heat aging)>
The above-mentioned unvulcanized sample was prepared and allowed to stand at room temperature for 24 hours, and then vulcanized under conditions of t90 + 5 minutes under a pressure of 160 ° C. and 6 MPa. After leaving for 7 days or 20 days, the same pulling test as the above initial adhesiveness was performed, and the rate of change in the drawing strength and the rubber coverage of the steel cord after drawing were measured.
The rate of change in drawing strength is the rate of change when the initial tensile strength is 100 (tensile strength after wet heat aging / tensile strength before wet heat aging × 100), and the rubber coverage of the steel cord after drawing is The rubber coverage of the steel cord after drawing was visually observed and evaluated from 0 to 100%.
In addition, the said measurement and evaluation were implemented by N = 10 (book), and calculated | required the average value. The results are shown in Table 5 below.

  As shown in Table 5 above, the rubber composition containing the resin compositions obtained in Examples 2, 3, 4 and 6 was after wet heat aging as compared with the rubber composition to which no resin adhesive was added. However, it has been found that the rubber-steel cord adhesive force is greatly improved, and the performance is equal to or better than the known resin adhesive “SUMIKANOL620”.

Claims (7)

The following general formula (1)

(R represents an alkyl group or a phenyl group which may have a branch.)
The resin composition containing the co-condensation resin which has the structural unit derived from phenols, resorcinol, and formaldehyde represented by these, and cashew nut shell liquid. The resin composition according to claim 1, wherein the content of the cashew nut shell liquid in the resin composition is 5 to 40% by weight. The resin composition according to claim 1 or 2, wherein the phenol represented by the general formula (1) is at least one selected from the group consisting of p-tert-butylphenol, o-phenylphenol, p-tert-octylphenol, and cresol. object. The resin composition according to any one of claims 1 to 3, wherein the phenols represented by the general formula (1) are p-tert-butylphenol and o-phenylphenol. The manufacturing method of the resin composition as described in any one of Claims 1-4 which includes the process of (I)-(III) in this order below.
(I) A step of obtaining a phenol resin by reacting one or more phenols represented by the general formula (1) with formaldehyde in the presence of an alkali.
(II) A step of reacting the phenolic resin with resorcin to obtain a cocondensation resin having structural units derived from phenols, resorcin and formaldehyde represented by the general formula (1).
(III) A step of mixing the co-condensation resin and cashew nut shell liquid. The method for producing a resin composition according to claim 5, wherein the steps (II) and (III) are carried out at 150 ° C or lower. The rubber composition containing the resin composition as described in any one of Claims 1-4.