JP6016297B2 - Cocondensate and rubber composition containing the same - Google Patents

Description

The present invention relates to a cocondensate obtained from an alkylphenol or the like, a rubber composition using the cocondensate, and a method for producing the cocondensate.

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, a cocondensate is obtained by reacting alkylphenols such as p-tert-octylphenol and p-nonylphenol with formalins, and the cocondensate is reacted with resorcin. Condensates are known. (For example, patent document 1).

JP-A-6-234824

Since rubber kneading is usually carried out at about 150 to 190 ° C., the cocondensate used as such an adhesive is required to be efficiently dispersed at this temperature, and the softening point of the cocondensate is at this temperature. If it is higher, it causes a dispersibility failure. These cocondensates have a unique odor derived from volatile components such as alkylphenols as raw materials, and it is preferable that the odor due to the volatile components is small from the viewpoint of the working environment.

On the other hand, in the process of searching for a new adhesive for use in rubber processing, the inventors of the present application often have carbon numbers such as p-tert-octylphenol and p-nonylphenol, which are often used as raw materials for cocondensates. When a cocondensate was synthesized by using p-tert-butylphenol having a small number of carbons as a raw material instead of alkylphenols having a large amount of carbon, it was found that the obtained resin had a very high softening point and was not preferable as an adhesive. .

The present invention is a co-condensate for adhesives used in the field of rubber products reinforced with a reinforcing material, and is a co-condensate using p-tert-butylphenol as an alkylphenol as a raw material. It is to provide a cocondensate that is efficiently dispersed.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have not used p-tert-butylphenol alone as a raw material of the cocondensate, but simultaneously with p-tert-butylphenol, the following formula (1)

(式中のRは、炭素数1〜3のアルキル基を表す。)
で示される置換フェノールとホルムアルデヒドとを、アルカリ触媒の存在下で反応させて得られるレゾール型縮合物に、さらにレゾルシンを反応させた共縮合物であって、前記共縮合物を構成するｐ−ｔｅｒｔ−ブチルフェノール成分（ユニット）と式（１）で表される置換フェノール成分（ユニット）の合計量に対するｐ−ｔｅｒｔ−ブチルフェノール成分（ユニット）の割合が、物質量（モル）基準で１０〜５０％であることを特徴とする共縮合物とすることにより、ｐ−ｔｅｒｔ−ブチルフェノールを原料として単独で使用した場合に比べ大幅に軟化点が低下し、混練時にゴムに効率よく分散する新規な共縮合物を提供することが可能であることを見出し、本発明を完成するに至った。具体的には下記〔１〕〜〔６〕記載の発明を含む。
〔１〕ｐ−ｔｅｒｔ-ブチルフェノールと、式（１）

(R in the formula represents an alkyl group having 1 to 3 carbon atoms.)
A co-condensate obtained by further reacting resorcin with a resole-type condensate obtained by reacting a substituted phenol represented by formula (II) with formaldehyde in the presence of an alkali catalyst, and constituting the co-condensate -The ratio of the p-tert-butylphenol component (unit) to the total amount of the substituted phenol component (unit) represented by the formula (1) and the butylphenol component (unit) is 10 to 50% based on the substance amount (mol). By using a cocondensate characterized by being a novel cocondensate that has a significantly lower softening point than p-tert-butylphenol used alone as a raw material and is efficiently dispersed in rubber during kneading. The present invention has been found to be able to be provided. Specifically, the inventions described in the following [1] to [6] are included.
[1] p-tert-butylphenol and the formula (1)

(式中のRは、炭素数1〜3のアルキル基を表す。)
で示される置換フェノールと、ホルムアルデヒドとを、アルカリ触媒の存在下で反応させて得られるレゾール型縮合物に、さらにレゾルシンを反応させて得られる共縮合物であって、前記共縮合物を構成するｐ−ｔｅｒｔ−ブチルフェノール成分（ユニット）と式（１）で表される置換フェノール成分（ユニット）の合計量に対するｐ−ｔｅｒｔ−ブチルフェノール成分（ユニット）の割合が、物質量（モル）基準で１０〜５０％であることを特徴とする共縮合物。
〔２〕
軟化点が８０℃以上１６０℃以下であることを特徴とする〔１〕に記載の共縮合物。
〔３〕請求項１または２記載の共縮合物中に含まれるｐ−ｔｅｒｔ-ブチルフェノール、式（１）で示される置換アルキルフェノール及びレゾルシンの総量が15重量％以下であることを特徴とする〔１〕または〔２〕に記載の共縮合物。
〔４〕
式（１）で示される置換アルキルフェノールがｐ−クレゾールであることを特徴とする〔１〕〜〔３〕
に記載の共縮合物。
〔５〕
〔１〕〜〔４〕いずれか一項に記載の共縮合物を含むことを特徴とするゴム組成物。
〔６〕
ｐ−ｔｅｒｔ-ブチルフェノールと式（１）で示される置換アルキルフェノールにホルムアルデヒドを加えて反応させることでレゾール型縮合物を得る工程と、得られたレゾール型縮合物にレゾルシンを加えて共縮合させる工程とを含むことを特徴とする〔１〕〜〔４〕に記載の共縮合物の製造方法。

(R in the formula represents an alkyl group having 1 to 3 carbon atoms.)
A co-condensate obtained by further reacting resorcin with a resole-type condensate obtained by reacting a substituted phenol represented by formula and formaldehyde in the presence of an alkali catalyst, and constituting the co-condensate The ratio of the p-tert-butylphenol component (unit) to the total amount of the p-tert-butylphenol component (unit) and the substituted phenol component (unit) represented by the formula (1) is 10 to 10 on the basis of the substance amount (mol). Cocondensate characterized by being 50%.
[2]
The cocondensate according to [1], wherein the softening point is 80 ° C or higher and 160 ° C or lower.
[3] The total amount of p-tert-butylphenol, substituted alkylphenol represented by the formula (1) and resorcin contained in the cocondensate according to claim 1 or 2 is 15% by weight or less [1] ] Or a cocondensate according to [2].
[4]
The substituted alkylphenol represented by the formula (1) is p-cresol [1] to [3]
Cocondensate described in 1.
[5]
[1] to [4] A rubber composition comprising the cocondensate according to any one of [1] to [4].
[6]
a step of obtaining a resole-type condensate by reacting p-tert-butylphenol with a substituted alkylphenol represented by the formula (1) by adding formaldehyde, and a step of adding resorcin to the resulting resole-type condensate and co-condensing them. The method for producing a cocondensate according to [1] to [4], wherein

According to the present invention, even when p-tert-butylphenol is used as a raw material, it can be efficiently dispersed in rubber during kneading, and the adhesion between the rubber obtained by vulcanizing it and the reinforcing material can be strengthened. A co-condensate useful as an adhesive between a reinforcing material and rubber can be provided.

Hereinafter, the present invention will be described in detail.

Formula (1) below

(式中のＲは、炭素数１〜３のアルキル基を表す。)
で表される置換フェノールとしては、ｐ−クレゾール、４−エチルフェノール、４−プロピルフェノールが例示されるが、この中でも入手性が良いことからｐ−クレゾールが好ましい。また、式（１）で表される置換フェノールの使用量は特に限定されないが、ｐ−ｔｅｒｔ-ブチルフェノール１モルに対し通常１〜１０倍モル使用し、好ましくは１．５〜１０倍モル使用する。

(R in the formula represents an alkyl group having 1 to 3 carbon atoms.)
As the substituted phenol represented by the formula, p-cresol, 4-ethylphenol, and 4-propylphenol are exemplified. Among these, p-cresol is preferable because of its high availability. Moreover, although the usage-amount of the substituted phenol represented by Formula (1) is not specifically limited, 1-10 times mole is normally used with respect to 1 mol of p-tert- butylphenol, Preferably it uses 1.5-10 times mole. .

As formaldehyde used in the present invention, in addition to formaldehyde itself, formalin which is an aqueous solution, and compounds that easily generate formaldehyde such as paraformaldehyde and trioxane can be used. The charge molar ratio of formaldehyde is not limited, but it is preferably 1 to 2 times the total amount of p-tert-butylphenol and the substituted phenol represented by the above formula (1), among which 1.1 to 1. A range of 5 moles is particularly preferred. When the amount is less than 1 mol, there is a concern that unreacted monomers increase and odor and volatile organic compounds increase. When the amount is more than 2 moles, a large amount of formaldehyde remains unreacted, and there is a concern that the resin has a three-dimensional structure and the softening point is increased.

As an alkali catalyst, what is used when manufacturing a normal resol type | mold condensate like the hydroxide or carbonate of an alkali metal or an alkaline-earth metal, ammonia, and an amine can be used. Specific examples of the alkali metal or alkaline earth metal hydroxide or carbonate include sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, and potassium carbonate. Among these, sodium hydroxide and potassium hydroxide are preferable. These alkalis can be used in the form of a solid or an aqueous solution, but it is preferable to use an aqueous solution in terms of reactivity and handling. When an aqueous solution is used, the concentration is usually 10% to 50% by weight. Although it does not normally limit as a preparation molar ratio of an alkali, The range of 0.03-0.2 times mole is preferable with respect to the total amount of the substituted phenol of p-tert- butylphenol and said Formula (1).

The reaction for obtaining the resol-type condensate can also be performed in a solvent. The solvent to be used is not particularly limited, and water, alcohol, aromatic hydrocarbon and the like can be used. Specifically, methanol, ethanol, propanol, butanol, toluene, xylene, ethylbenzene, cumene, monochlorobenzene and the like are exemplified. Of these, water, toluene, and xylene are preferable. These solvents can be used alone or in combination of two or more. The reaction for obtaining the resol-type condensate is usually carried out at a reaction temperature of 40 to 100 ° C. for 1 to 8 hours.

The molar ratio of resorcin charged is not particularly limited, but it is preferably in the range of 0.5 to 4.0 times the total amount of p-tert-butylphenol and the substituted phenol of formula (1). A range of .8 to 1.2 times is particularly preferable.

The reaction between the resole-type condensate and resorcin can also be performed in a solvent. The solvent to be used is not particularly limited, and water, alcohol, aromatic hydrocarbon and the like can be used. Specifically, methanol, ethanol, propanol, butanol, toluene, xylene, ethylbenzene, cumene, monochlorobenzene and the like are exemplified. Of these, water, toluene, and xylene are preferable. These solvents can be used alone or in combination of two or more. The reaction between the resole-type condensate and resorcin is usually carried out at a reaction temperature of 40 to 150 ° C. for 1 to 8 hours.

The cocondensate of the present invention thus obtained is p-tert-butylphenol relative to the total amount of the p-tert-butylphenol component (unit) constituting the cocondensate and the substituted phenol component (unit) represented by formula (1). The ratio of the component (unit) is 10 to 50% on the basis of the substance amount (mol). This ratio is determined by analyzing the obtained cocondensate by ¹ H-NMR and performing the following calculation: (integral value of protons derived from p-tert-butyl group / 9) / [(p- integral value of protons derived from tert-butyl group / 9) + (integral value of protons derived from alkyl group (R) derived from substituted phenol represented by formula (1)) / (number of protons of alkyl group)] × 100
If it is higher than 50%, the softening point becomes high and the rubber is not efficiently dispersed during kneading.

The total amount of unreacted monomer p-tert-butylphenol, substituted alkylphenol represented by formula (1) and resorcin contained in the cocondensate of the present invention is not particularly limited, but is preferably 15% by weight or less. . By setting the content to 15% by weight or less, the odor can be reduced, and the volatile organic compound is reduced.

The softening point of the cocondensate of the present invention is not particularly limited, but is preferably in the range of 80 ° C to 190 ° C. Of these, 90 ° C. to 160 ° C. is particularly preferable. If it is lower than 80 ° C., there is a concern of blocking during storage, and if it is higher than 190 ° C., there is a concern of poor dispersion when kneaded with the rubber component.

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

Although the usage-amount of said cocondensate is not specifically limited, Usually, it is used in the range of 0.5-10 weight part per 100 weight part of rubber components. 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. Absent.

Rubber components 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 rubber (BR), and acrylonitrile. -Various synthetic rubbers such as butadiene copolymer rubber (NBR), isoprene / isobutylene copolymer rubber (IIR), ethylene / propylene-diene copolymer rubber (EPDM), halogenated butyl rubber (HR), etc. are exemplified. Highly unsaturated rubbers such as rubber, styrene / butadiene copolymer rubber and polybutadiene rubber are preferably used. 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.

Natural rubber is preferred as the rubber component, and the proportion of natural rubber in the rubber component is preferably 70% by weight or more.

Examples of the filler include carbon black, silica, talc, clay, aluminum hydroxide, titanium oxide and the like that are usually used in the rubber field. Carbon black and silica are preferably used, and carbon black is particularly preferable. Preferably used. Examples of the carbon black include those described on page 494 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. HAF (High Abrasion Furnace), SAF (Super Abrasion Furnace), ISAF (Intermediate). Carbon blacks such as SAF), FEF (Fast Extrusion Furnace), MAF, GPF (General Purpose Furnace), and SRF (Semi-Reinforcing Furnace) are preferred. For the tire tread rubber composition, carbon black having a CTAB surface area of 40 to 250 m @ 2 / g, a nitrogen adsorption specific surface area of 20 to 200 m @ 2 / g, and a particle diameter of 10 to 50 nm is preferably used, and a carbon black having a CTAB surface area of 70 to 180 m @ 2 / g. More preferable examples include N110, N220, N234, N299, N326, N330, N330T, N339, N343, and N351 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., manufactured by Degussa "Ultrasil (registered trademark) VN3", "Ultrasil (registered trademark) 360", "Ultrasil (registered trademark) 7000", "Zeosil (registered trademark) 115GR", "Zeosil (registered trademark) 1115MP" manufactured by Rhodia Commercially available products such as “Zeosil (registered trademark) 1205MP”, “Zeosil (registered trademark) Z85MP”, and “Nip Seal (registered trademark) AQ” manufactured by Nippon Silica Co., Ltd. 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 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.

The amount of the filler used is not particularly limited, but 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.

The filler is preferably carbon black, and the proportion of carbon black in the filler is preferably 70% by weight or more.

Examples of the sulfur component 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 include thiazole-based vulcanization accelerators and sulfur compounds described on pages 412 to 413 of Rubber Industry Handbook <Fourth Edition> (issued by the Japan Rubber Association on January 20, 1994). Examples thereof include phenamide vulcanization accelerators and guanidine vulcanization accelerators.

Specifically, for example, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS), N, N-dicyclohexyl-2 -Benzothiazolylsulfenamide (DCBS), 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), diphenylguanidine (DPG). Among them, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS), N, N-dicyclohexyl-2-benzothiazolylsulfur It is preferable to use phenamide (DCBS) or dibenzothiazyl disulfide (MBTS) and diphenylguanidine (DPG) in combination.

Although the usage-amount of a vulcanization accelerator is not specifically limited, The range of 0.5-3 weight part per 100 weight part of rubber components is preferable. In particular, the range of 0.5 to 1.2 parts by weight is particularly preferable.

Although the usage-amount of zinc oxide is not specifically limited, The range of 3-15 weight part per 100 weight part of rubber components is preferable. Among these, the range of 5 to 10 parts by weight is particularly preferable.

Examples of the formaldehyde generator include those usually used in the rubber industry such as hexamethylenetetramine, hexakis (methoxymethyl) melamine, pentakis (methoxymethyl) methylolmelamine, and tetrakis (methoxymethyl) dimethylolmelamine. 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 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). . 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 rubber composition containing the cocondensate of the present invention can be obtained, for example, by the following method.

(A) Process of kneading filler and rubber component The filler and rubber component can be kneaded 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., and more preferably (more) in the range of 150 ° C. to 170 ° C. The kneading time is about 5 to 10 minutes.

(B) The kneaded product obtained in step A, the sulfur component and the vulcanization accelerator are kneaded. 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.

The cocondensate, zinc oxide, antioxidant, oil, fatty acids and peptizer of the present invention are preferably added in the step (A).

The retarder is preferably added in the step (B).

The rubber composition containing the cocondensate 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.

The rubber composition containing the cocondensate 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. In addition, this invention is not limited at all by these examples.

The analysis and performance evaluation of the cocondensate were performed as follows.
"Measurement of average molecular weight of resin"
The average molecular weight of the cocondensate was calculated as a polystyrene-converted weight average molecular weight by gel permeation chromatography (GPC).

"Measurement of residual monomer and solvent"
The residual monomer and residual solvent were quantified by gas chromatography based on the following conditions.
Equipment used: Gas chromatograph GC-14B manufactured by Shimadzu Corporation
Column: Glass column outer diameter 5mm x inner diameter 3.2mm x length 3.1m
Filler: Filler Silicone OV-17 10% Chromosorb WHP 80 / 100meshx, max.temp. 340 ℃
Column temperature: 80 ° C → 280 ° C
Vaporization chamber temperature: 250 ° C
Detector temperature: 280 ° C
Detector: FID
Carrier: N ₂ (40ml / min)
Combustion gas: Hydrogen (60kPa), Air (60kPa)
Injection volume: 2 μL
1 g of a resin crosslinking agent and 0.05 g of anisole as a standard were dissolved in 10 mL of acetone and analyzed under the above conditions. Residual solvent and residual monomer content (%) in the resin was measured by an internal standard method (GC-IS method).
The contents (%) described in the texts of the examples and comparative examples are expressed as weight percent unless otherwise specified.

"Measurement of softening point"
Measured by a method based on JIS-K2207. A material having a softening point exceeding 190 ° C. is not preferable as an adhesive between a reinforcing material and rubber because of its poor dispersibility in rubber.

“Ratio of the p-tert-butylphenol component (unit) to the total amount of the p-tert-butylphenol component (unit) constituting the cocondensate and the substituted phenol component (unit) represented by the formula (1)”
¹ H-NMR analysis was performed by a method based on the following conditions, and calculation was performed based on the calculation formula described in [0019].
Equipment: “JMN-ECS” (400 MHz) manufactured by JEOL Ltd.
Solvent: Chemical shift of each component of deuterium-substituted dimethyl sulfoxide: Tetramethylsilane was used as a reference (0 ppm), and the peaks shown in the following values were taken as the peaks of the respective components.
Proton of p-tert-butyl group derived from p-tert-butylphenol: 1.0 to 1.2 ppm
Proton of methyl group derived from p-cresol (alkyl group (R) derived from substituted phenol represented by formula (1)): 1.9 to 2.3 ppm

A four-necked separable flask equipped with a reflux condenser and a thermometer was charged with 43.5 g (1.33 mol) of paraformaldehyde having a purity of 92%, 75.0 g (0.50 mol) of p-tert-butylphenol, and 54.0 g (0.50 mol) of p-cresol. ) And 75.0 g of toluene were sequentially added. Thereafter, the internal temperature was raised to 45 ° C., 4.16 g (0.05 mol) of a 48% 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 kept at that temperature for 2 hours. Thereafter, the temperature was raised again until the internal temperature reached 80 ° C., and the temperature was further maintained for 1.5 hours.
After completion of the reaction, the mixture was cooled to an internal temperature of 75 ° C. or less, neutralized by adding 3.15 g (0.025 mol) of oxalic acid dihydrate, and then added with 110 g (1.00 mol) of resorcin, and an internal temperature of 108 to 111 ° C. The temperature was raised to azeotropic dehydration over 4 hours. Subsequently, the temperature was raised to an internal temperature of 145 to 150 ° C. with normal pressure, and the solvent toluene was distilled off by keeping the temperature for 2 hours. Thereafter, the pressure was reduced to 16 kPa while maintaining the internal temperature at 140 to 150 ° C., and the solvent toluene was further distilled off by keeping the temperature for 2 hours.
By the above operation, 259 g of orange cocondensate was obtained.
Average molecular weight of the cocondensate: 1334, softening point of the cocondensate: 184.6 ° C., residual toluene content in the cocondensate: 1.4%, residual p-tert-butylphenol content: 4.4%, residual p-cresol content: 2.7% Residual resorcin content: 5.5%. Ratio of p-tert-butyl group to the total amount of p-tert-butyl group and R: 50%.

In Example 1, the synthesis was performed under the same conditions except that the amount of p-tert-butylphenol charged was changed to 60.0 g (0.40 mol) and the amount of p-cresol charged was changed to 64.8 g (0.60 mol).
By the above operation, 253 g of orange cocondensate was obtained.
Average molecular weight of the cocondensate: 1425, softening point of the cocondensate: 156.4 ° C., residual toluene content in the cocondensate: 1.5%, residual p-tert-butylphenol content: 4.9%, residual p-cresol content: 3.3% Residual resorcin content: 4.2%. Ratio of p-tert-butyl group to the total amount of p-tert-butyl group and R: 41%.

In Example 1, the synthesis was performed under the same conditions except that the amount of p-tert-butylphenol charged was changed to 50.0 g (0.33 mol) and the amount of p-cresol charged was changed to 72.0 g (0.66 mol).
By the above operation, 248 g of orange cocondensate was obtained.
Average molecular weight of cocondensate: 1223, softening point of cocondensate: 109.8 ° C., residual toluene content in cocondensate: 0.4%, residual p-tert-butylphenol content: 3.7%, residual p-cresol content: 6.4% Residual resorcin content: 11.5%. Ratio of p-tert-butyl group to the total amount of p-tert-butyl group and R: 33%.

<Comparative Example 1>
In a four-necked separable flask equipped with a reflux condenser and a thermometer, paraformaldehyde 43.5 g (1.33 mol) with a purity of 92%, p-tert-butylphenol 100 g (0.67 mol), p-cresol 36.0 g (0.33 mol) Then, 75.0 g of toluene was sequentially added. Thereafter, the internal temperature was raised to 45 ° C., 4.16 g (0.05 mol) of a 48% 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 kept at that temperature for 2 hours. Thereafter, the temperature was raised again until the internal temperature reached 80 ° C., and the temperature was further maintained for 1.5 hours.
After completion of the reaction, the mixture was cooled to an internal temperature of 75 ° C. or less, neutralized by adding 3.15 g (0.025 mol) of oxalic acid dihydrate, and then added with 110 g (1.00 mol) of resorcin, and an internal temperature of 108 to 111 ° C. The temperature was raised to azeotropic dehydration over 4 hours. Subsequently, the temperature was raised to an internal temperature of 145 to 150 ° C. with normal pressure, and the solvent toluene was distilled off by keeping the temperature for 2 hours. Thereafter, the pressure was reduced to 16 kPa while maintaining the internal temperature at 140 to 150 ° C., and the solvent toluene was further distilled off by keeping the temperature for 2 hours.
By the above operation, 273 g of orange cocondensate was obtained.
Average molecular weight of the cocondensate: 1306, softening point of the cocondensate: 195 ° C. or higher, residual toluene content in the cocondensate: 0.8%, residual p-tert-butylphenol content: 2.9%, residual p-cresol content: 0.9 %, Resorcin content: 7.5%. Ratio of p-tert-butyl group to the total amount of p-tert-butyl group and R: 67%.

<Comparative example 2>
Synthesis was carried out under the same conditions as in Comparative Example 1, except that the amount of p-tert-butylphenol charged was changed to 150 g (1.00 mol) and that the amount of p-cresol was not charged.
By the above operation, 286 g of orange cocondensate was obtained.
Average molecular weight of the cocondensate: 1212, softening point of the cocondensate: 195 ° C. or higher, residual toluene content in the cocondensate: 2.0%, residual p-tert-butylphenol content: 2.6%, residual resorcin content: 10.0%.

  The cocondensate obtained by the present invention can be used as an adhesive between rubber and various reinforcing materials by kneading into the rubber composition.

Claims (6)

p-tert-butylphenol and the formula (1)

(R in the formula represents an alkyl group having 1 to 3 carbon atoms.)
A co-condensate obtained by further reacting resorcin with a resole-type condensate obtained by reacting a substituted phenol represented by formula and formaldehyde in the presence of an alkali catalyst, and constituting the co-condensate The ratio of the p-tert-butylphenol component (unit) to the total amount of the p-tert-butylphenol component (unit) and the substituted phenol component (unit) represented by the formula (1) is 10 to 10 on the basis of the substance amount (mol). Cocondensate characterized by being 50%. 2. The cocondensate according to claim 1, wherein the softening point is 80 ° C. or higher and 160 ° C. or lower. The total amount of p-tert-butylphenol, which is a monomer remaining in the cocondensate according to claim 1 or 2, the substituted alkylphenol represented by the formula (1), and resorcin is 15% by weight or less. The cocondensate according to 1 or 2. The co-condensate according to any one of claims 1 to 3, wherein the substituted alkylphenol represented by the formula (1) is p-cresol. A rubber composition comprising the cocondensate according to any one of claims 1 to 4. a step of obtaining a resole-type condensate by reacting p-tert-butylphenol with a substituted alkylphenol represented by the formula (1) by adding formaldehyde, and a step of adding resorcin to the obtained resole-type condensate and co-condensing them. The manufacturing method of the cocondensate as described in any one of Claims 1-4 characterized by the above-mentioned.