JP2013249416A - Rubber composition and crosslinked rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition that sufficiently maintains the effect of an anti-aging substance for rubber.SOLUTION: A rubber composition comprises (a) an anti-aging agent for rubber containing mesoporous silica having a BET specific surface area of 20-200 m/g and an anti-aging substance for rubber and (b) a rubber component.

Description

  The present invention relates to a rubber composition and a crosslinked rubber composition.

  Patent Document 1 contains porous hollow silica impregnated or filled with N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, which is an anti-aging agent for rubber, and a rubber component. A rubber composition is described.

JP 2011-132471 A

  In the conventional crosslinked rubber composition containing an anti-aging substance for rubber, the anti-aging substance for rubber migrates in the crosslinked rubber composition (finally, the anti-aging substance for rubber bleeds out to the surface), and the anti-aging is prevented. In some cases, the effect was not sufficiently sustained. The present invention has been made paying attention to such circumstances, and its purpose is to provide a rubber anti-aging agent in which the migration of rubber anti-aging substances is suppressed and the anti-aging effect is sufficiently sustained. There is to do.

  As a result of intensive studies by the present inventors, by using a rubber anti-aging substance in combination with a mesoporous silica having a specific BET specific surface area, the migration of the rubber anti-aging substance in the crosslinked rubber composition is suppressed. It was found that the anti-aging effect can be sufficiently sustained. The present invention based on this finding is as follows.

[1] A rubber anti-aging agent containing (a) mesoporous silica having a BET specific surface area of 20 to ²⁰⁰ m ² / g and an anti-aging agent for rubber, and (b) a rubber composition containing a rubber component.
[2] (a) An anti-aging agent for rubber containing mesoporous silica having a BET specific surface area of 20 to ²⁰⁰ m ² / g and an anti-aging agent for rubber, and (b) obtained by kneading a rubber component. Rubber composition.
[3] The rubber composition according to [1] or [2], wherein the rubber anti-aging substance is supported on the mesoporous silica.
[4] The rubber composition according to any one of the above [1] to [3], wherein the rubber anti-aging substance is a compound represented by the formula (I).

(In formula (I), R ¹ represents a hydrogen atom or an alkyl group having 1 to 13 carbon atoms.)
[5] The rubber composition according to any one of the above [1] to [4], wherein the content of mesoporous silica is 1 to 50 parts by mass with respect to 10 parts by mass of the antiaging substance for rubber.
[6] A crosslinked rubber composition obtained by crosslinking the rubber composition according to any one of [1] to [5].
[7] A tire comprising the crosslinked rubber composition according to [6].
[8] A sidewall, an inner liner, a cap tread or an under tread for a tire including the crosslinked rubber composition according to [6].
[9] A tire belt including a steel cord coated with the crosslinked rubber composition according to [6].
[10] A tire carcass including a carcass fiber cord covered with the crosslinked rubber composition according to [6].

  In the crosslinked rubber composition containing both the rubber anti-aging substance and the specific mesoporous silica, the anti-aging effect of the rubber anti-aging substance is sufficiently sustained.

It is a figure explaining the method to measure the transfer amount of the anti-aging substance for rubber | gum of a crosslinked rubber composition.

<Anti-aging agent for rubber>
The rubber composition and the crosslinked rubber composition of the present invention are characterized by containing an anti-aging agent for rubber containing both an anti-aging agent for rubber and a specific mesoporous silica, instead of the anti-aging agent for rubber alone. Therefore, first, the antiaging substance for rubber and the specific mesoporous silica will be described in order.

<Rubber aging prevention substances>
The anti-aging substance for rubber in the present invention is an organic substance blended for the purpose of preventing the aging of the rubber product and extending its life. Only one type of rubber anti-aging substance may be used, or two or more types may be used in combination.

  The anti-aging substance for rubber is not particularly limited. For example, amine-based anti-aging agent, amine-ketone-based anti-aging agent, phenol-based anti-aging agent, imidazole-based anti-aging agent, sulfur-based anti-aging agent, phosphorus-based anti-aging agent. Examples include inhibitors. Specifically, those described in pages 436 to 443 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association, reaction products of aniline and acetone (TMDQ), synthetic wax (paraffin) Wax, etc.), vegetable wax and the like.

  The anti-aging agent for rubber tends to migrate in the crosslinked rubber composition as the molecular weight decreases. From the point that the effect of the present invention of suppressing the migration can be further exhibited, the rubber anti-aging substance preferably has a relatively low molecular weight, more preferably has a molecular weight of about 150 to 600, and a molecular weight of 150 to 600. What is about 400 is still more preferable.

  As the rubber anti-aging substance, an amine-based anti-aging substance is preferable. As an amine type anti-aging substance, for example, formula (I):

(In formula (I), R ¹ represents a hydrogen atom or an alkyl group having 1 to 13 carbon atoms.)
A compound of formula (II):

(In Formula (II), R ² represents a hydrogen atom or an alkyl group having 1 to 13 carbon atoms. R ³ represents a hydrogen atom or an alkoxy group having 1 to 13 carbon atoms.)
Or a polymer thereof or the like.

  The alkyl group having 1 to 13 carbon atoms may be linear or branched, and is preferably branched. The carbon number is preferably 1 to 10, more preferably 2 to 8. The alkoxy group having 1 to 13 carbon atoms may be linear or branched. The carbon number is preferably 1 to 10, more preferably 2 to 8.

R ¹ is preferably an alkyl group having 1 to 13 carbon atoms, more preferably a branched alkyl group having 3 to 8 carbon atoms, still more preferably isopropyl or 1,3-dimethylbutyl, particularly preferably. Is 1,3-dimethylbutyl. R ² is preferably a hydrogen atom. R ³ is preferably a hydrogen atom or an alkoxy group having 1 to 5 carbon atoms, more preferably a hydrogen atom or ethoxy.

  Examples of the compound represented by the formula (I) include N-isopropyl-N′-phenyl-p-phenylenediamine (IPPD) and N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine. (6PPD). Examples of the compound represented by the formula (II) include 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (ETMDQ), 2,2,4-trimethyl-1,2-dihydroquinoline and the like. Can be mentioned. Examples of the polymer of the compound represented by the formula (II) include poly (2,2,4-trimethyl-1,2-dihydroquinoline) (“Antioxidant FR” manufactured by Matsubara Sangyo Co., Ltd.). In these, the compound shown by Formula (I) is preferable, N-isopropyl-N'-phenyl-p-phenylenediamine, N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine Are more preferable, and N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine is more preferable.

<Mesoporous silica>
The mesoporous silica used in the present invention is mesoporous silica having a BET specific surface area of 20 to ²⁰⁰ m ² / g. Here, in the present invention, the mesoporous silica means silica having pores (mesopores) having a diameter of 2 to 50 nm. In IUPAC, in the field of catalysis, a hole having a width exceeding about 50 nm is called a macro hole, a hole having a width not exceeding about 2 nm is called a micro hole, and a hole having an intermediate size is called a meso hole. If the BET specific surface area of the mesoporous silica used is 200 m ² / g or less, the migration of the rubber anti-aging substance can be sufficiently suppressed.

The BET specific surface area of mesoporous silica is preferably 10 to 150 m ² / g, more preferably 10 to 130 m ² / g or less, and still more preferably 10 to 120 m ² / g or less. This BET specific surface area can be measured by the method described in Examples described later.

The particle diameter of the mesoporous silica used in the present invention is preferably 1.0 to 10.0 μm, more preferably 1.0 to 7.0 μm. The particle size analyzes the particle size distribution of the mesoporous silica by laser diffraction method, the value of D ₅₀ obtained from the chart.

  The mesoporous silica may be used alone or in combination of two or more. The mesoporous silica is commercially available from ABCNANOTECH, for example, under the product names SILNOS 130, SILNOS 230, and SILNOS 260OTS.

  The content of the mesoporous silica in the anti-aging agent for rubber is preferably 1 to 50 parts by weight, more preferably 1 to 40 parts by weight, and still more preferably 1 to 30 parts with respect to 10 parts by weight of the anti-aging material for rubber. Part by mass. When the content is 1 part by mass or more, the durability of the anti-aging performance is excellent. Conversely, when the content is 50 parts by mass or less, the physical properties of the crosslinked rubber composition are improved.

<Method for producing anti-aging agent for rubber>
The rubber anti-aging agent can be obtained by mixing a rubber anti-aging material and the mesoporous silica. The rubber anti-aging agent is preferably one in which a rubber anti-aging substance is supported on the mesoporous silica. Here, the carrying | support in this invention means that the antiaging substance for rubbers has adhered to the surface of mesoporous silica, or the inside (namely, surface of a hole). The rubber anti-aging agent in which the rubber anti-aging substance is supported on the mesoporous silica can be produced by, for example, the following method (1), the following method (2) and the like.

(1) A method in which after the rubber anti-aging substance is dissolved in a solvent, the solution and mesoporous silica are mixed to remove the solvent.
Here, the “solvent” is not particularly limited as long as it can dissolve the rubber anti-aging substance and can be removed (for example, distilled off), but for example, toluene, xylene, hexane, heptane, etc. Examples thereof include hydrocarbon solvents, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and alcohol solvents such as methanol, ethanol, and isopropanol.
In this method, there is no particular limitation on the mixing method of the rubber anti-aging substance solution and the mesoporous silica. For example, the mesoporous silica may be added to the solution, or the solution may be sprayed on the mesoporous silica. In the method, the solid obtained after removing the solvent may be pulverized as necessary.

(2) A method in which after the rubber anti-aging material is melted, the melt and mesoporous silica are mixed and cooled.
In this method, the method for cooling the mixture is not particularly limited, and for example, forced air cooling by blowing or cooling can be employed. In this method, the solid obtained after cooling may be pulverized as necessary.

<Rubber composition>
The rubber composition of the present invention can be obtained by kneading the rubber anti-aging agent and a rubber component.

  The rubber anti-aging agent may be used alone or in combination of two or more. Similarly, only 1 type may be used for a rubber component and it may use 2 or more types together. The kneading is not particularly limited and can be performed by a known method. The rubber composition of the present invention is, for example, a master batch (usually, a solid or a granular material in which a large amount of the antioxidant for rubber and a rubber component are pre-kneaded before producing a crosslinked rubber composition). May be. The rubber composition of the present invention may further contain other compounding agents (for example, a filler, zinc oxide, stearic acid, a crosslinking agent, a vulcanization accelerator, etc.). Each compounding agent may be used alone or in combination of two or more.

  When a crosslinking agent (or sulfur and vulcanization accelerator) is blended in the rubber composition, the crosslinking agent (or sulfur and vulcanization accelerator) and the rubber anti-aging agent may be kneaded together with the rubber component. The kneaded product and the crosslinking agent (or sulfur and vulcanization accelerator) may be further kneaded after kneading the rubber anti-aging agent and the rubber component.

When the rubber composition of the present invention is a masterbatch, the content of the rubber anti-aging agent in the rubber composition is, for example, 0.1 to 990 parts by mass, preferably 0 with respect to 100 parts by mass of the rubber component. 0.1 to 900 parts by mass, more preferably 0.1 to 700 parts by mass, and particularly preferably 0.1 to 500 parts by mass.
When the rubber composition of the present invention is a rubber composition obtained by adding a rubber component and, if necessary, a compounding agent to a masterbatch, the content of the rubber anti-aging agent in the rubber composition is rubber. It is 0.1-50 mass parts with respect to 100 mass parts of components, Preferably it is 0.5-30 mass parts, More preferably, it is 1-20 mass parts.

  Examples of the rubber component include natural rubber and modified natural rubber (for example, epoxidized natural rubber, deproteinized natural rubber, etc.); polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR). Various synthetic rubbers such as acrylonitrile / butadiene copolymer rubber (NBR), isoprene / isobutylene copolymer rubber (IIR), ethylene / propylene-diene copolymer rubber (EPDM), halogenated butyl rubber (HR), etc. it can. The rubber component is preferably highly unsaturated, and natural rubber, modified natural rubber, styrene / butadiene copolymer rubber, and polybutadiene rubber are more preferable, and natural rubber is more preferable. Moreover, you may use together the above-mentioned various rubber | gum. Examples of combined use include use of natural rubber and styrene / butadiene copolymer rubber, use of natural rubber and polybutadiene rubber, and the like.

Examples of the natural rubber include grades of natural rubber such as RSS # 1, RSS # 3, TSR20, and SIR20.
Examples of the epoxidized natural rubber include those having a degree of epoxidation of 10 to 60 mol% (for example, ENR25, ENR50, etc. manufactured by Kumpoulan Guthrie).
Examples of the deproteinized natural rubber include a deproteinized natural rubber having a total nitrogen content of 0.3% by mass or less.
Examples of other modified natural rubbers are obtained by reacting natural rubber with 4-vinylpyridine, N, N-dialkylaminoethyl acrylate (for example, N, N-diethylaminoethyl acrylate), 2-hydroxy acrylate, and the like. And modified natural rubber containing a polar group.

  Examples of the styrene-butadiene copolymer rubber (SBR) include emulsion polymerization SBR and solution polymerization SBR described in pages 210 to 211 of the “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. Can be mentioned.

Examples of preferable rubber components of the rubber composition for tread and the rubber composition for sidewall include the following.
(1) Solution polymerization SBR.
(2) Modified solution polymerization SBR. Examples of the modified solution polymerization SBR include the following.
(I) Solution polymerization SBR in which molecular ends are modified with 4,4′-bis- (dialkylamino) benzophenone such as “Nippol (registered trademark) NS116” manufactured by Nippon Zeon.
(Ii) Solution polymerization SBR in which molecular terminals are modified using a tin halide compound such as “SL574” manufactured by JSR.
(Iii) Silane-modified solution polymerization SBR such as “E10” and “E15” manufactured by Asahi Kasei Corporation.
(Iv) Molecules using any of lactam compounds, amide compounds, urea compounds, N, N-dialkylacrylamide compounds, isocyanate compounds, imide compounds, silane compounds having an alkoxy group (trialkoxysilane compounds, etc.) and aminosilane compounds Solution polymerization SBR having nitrogen or silicon elements at the molecular ends, obtained by modifying the ends.
(V) Multiple elements of nitrogen, tin, and silicon at the molecular ends obtained by modifying the molecular ends using two or more different compounds such as tin compounds, alkylacrylamide compounds, and silane compounds having an alkoxy group Solution polymerized SBR.
(3) Oil-extended SBR in which oil such as process oil and aroma oil is added after emulsion polymerization SBR and solution polymerization SBR.

  Examples of the polybutadiene rubber (BR) include high cis BR having a cis bond of 90% or more, solution polymerization BR such as low cis BR having a cis bond of around 35%, and low cis BR having a high vinyl content. Among these, low cis BR having a high vinyl content is preferable.

More preferable polybutadiene rubber (BR) includes, for example, the following.
(1) Tin-modified BR such as “Nipol (registered trademark) BR 1250H” manufactured by ZEON.
(2) 4,4′-bis- (dialkylamino) benzophenone, tin halide compound, lactam compound, amide compound, urea compound, N, N-dialkylacrylamide compound, isocyanate compound, imide compound, silane having an alkoxy group A solution polymerized BR having an element of nitrogen, tin or silicon at the molecular terminal obtained by modifying the molecular terminal with either a compound (trialkoxysilane compound or the like) and an aminosilane compound.
(3) Multiple elements of nitrogen, tin, and silicon at the molecular ends obtained by modifying the molecular ends using two or more different compounds such as tin compounds, alkylacrylamide compounds, and silane compounds having an alkoxy group. Solution polymerized BR having

  Polybutadiene rubber (BR) is preferable as the rubber component of the rubber composition for treads and the rubber composition for sidewalls. BR is usually used in a blend of SBR and / or natural rubber. In the case of a rubber composition for a tread, the content of SBR and natural rubber (or the total amount of SBR and natural rubber) in the rubber component is, for example, 60 to 100% by mass, and the content of BR is, for example, 0 to 40% by mass. In the case of the rubber composition for a sidewall, the content of SBR and natural rubber (or the total amount of SBR and natural rubber) in the rubber component is, for example, 10 to 70% by mass, and the BR content is For example, it is 90-30 mass%. In the case of the rubber composition for sidewall, the content of natural rubber in the rubber component is preferably 40 to 60% by mass, and the content of BR is preferably 60 to 40% by mass. In the case of sidewall rubber, a blend of modified SBR and non-modified SBR or a blend of modified BR and non-modified BR can also be preferably used.

  Examples of the filler include carbon black, silica, talc, clay, titanium oxide and the like that are usually used in the rubber field. Among these, carbon black and silica are preferable, and carbon black is more preferable.

  Examples of the carbon black include those described on page 494 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. Preferably, for example, HAF (High Abrasion Furnace), SAF (Super Abrasion Furnace), ISAF (Intermediate SAF), FEF (Fast Extrusion Furnace), MAF (Medium Abrasion Furnace), GPF (General Purpose Furnace), SRF (Semi-Furnace) Carbon black such as Reinforcing Furnace).

If the tread rubber composition is preferably, CTAB (Cetyl Tri-methyl Ammonium Bromide) a specific surface area 40~250m ² / g, nitrogen adsorption specific surface area 20 to 200 m ² / g, carbon black having a particle diameter 10~50nm Can be mentioned. More preferably, for example, carbon black having a CTAB specific surface area of 70 to 180 m ² / g can be used. Specifically, for example, in the ASTM standard, N110, N220, N234, N299, N326, N330, N330T, N339, N343, N351 and the like can be mentioned. Moreover, as a preferable thing, the surface treatment carbon black which made silica adhere to the surface of carbon black 0.1-50 mass% can also be mentioned. More preferably, for example, a combination of carbon black and silica, a combination of several kinds of fillers, and the like can be given.

  In the case of a rubber composition for a tread, it is preferable to use carbon black alone or a combination of carbon black and silica as a filler.

In the case of the rubber composition for carcass and the rubber composition for sidewall, carbon black having a CTAB specific surface area of 20 to 60 m ² / g and a particle diameter of 40 to 100 nm is preferable as the filler. Specifically, for example, in the ASTM standard, N330, N339, N343, N351, N550, N568, N582, N630, N642, N660, N662, N754, N762 and the like can be mentioned.

  When using a filler, the content in the rubber composition is not particularly limited, but is, for example, 5 to 100 parts by mass with respect to 100 parts by mass of the rubber component. When only carbon black is used as a filler, the content thereof is preferably 30 to 80 parts by mass with respect to 100 parts by mass of the rubber component. Moreover, when using the combination of carbon black and a silica as a filler in a tread member use, Preferably content of carbon black is 5-60 mass parts with respect to 100 mass parts of rubber components. As a compounding ratio (mass ratio) of silica / carbon black, the range of 0.7 / 1-1 / 0.1 can be mentioned, for example.

Examples of the filler include silica having a CTAB specific surface area of 50 to 180 m ² / g, silica having a nitrogen adsorption specific surface area of 50 to 300 m ² / g, and the like. Examples of commercially available products of silica include “AQ” and “AQ-N” manufactured by Tosoh Silica Co., Ltd., “Ultrasil (registered trademark) VN3”, “Ultrasil (registered trademark) 360”, and “Ultrasil” manufactured by Degussa. (Registered trademark) 7000 "," Zeosil (registered trademark) 115GR "," Zeosil (registered trademark) 1115MP "," Zeosil (registered trademark) 1205MP "," Zeosil (registered trademark) Z85MP ", manufactured by Nippon Silica Co., Ltd. “Nip seal (registered trademark) AQ” and the like. Further, for example, (i) silica having a pH of 6 to 8, (ii) silica containing sodium in an amount of 0.2 to 1.5 mass%, (iii) having a roundness of 1 to 1.3 Spherical silica, (iv) Silicone oil such as dimethylsilicone oil; Organosilicon compound containing ethoxysilyl group; Silica surface-treated with alcohol such as ethanol and polyethylene glycol, (v) Different nitrogen adsorption specific surface area You may mix | blend the mixture etc. of 2 or more types of silica as a filler.

  In addition, when silica is used as the filler, a silane coupling agent, a compound that can be bonded to silica (for example, a compound that can be bonded to silica or a compound having a functional group such as an alkoxysilyl group) Is preferably added. Examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide (eg, “Si-69” manufactured by Degussa), bis (3-triethoxysilylpropyl) disulfide (eg, manufactured by Degussa “ Si-75 "), bis (3-diethoxymethylsilylpropyl) tetrasulfide, bis (3-diethoxymethylsilylpropyl) disulfide, octanethioic acid S- [3- (triethoxysilyl) propyl] ester (" 3- Also referred to as “octanoylthiopropyltriethoxysilane”, for example, “NXT silane” manufactured by General Electronic Silicones), octanethioic acid S- [3-{(2-methyl-1,3-propanedialkoxy) ethoxysilyl} propyl ] Ester, octanethioic acid S- [3-{(2-methyl- , 3-propanedialkoxy) methylsilyl} propyl] ester, methyltrimethoxysilane, methyltriethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isobutyltrimethoxysilane, isobutyltri Ethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, 3 -Methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopro Rutriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, (3-glycidoxypropyl) trimethoxysilane, (3-Glycidoxypropyl) triethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-isocyanate Examples thereof include propyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane.

  The addition timing of the silane coupling agent and the compound capable of binding to silica is not particularly limited, but it is preferable to blend it with the rubber component simultaneously with silica. When using these, the compounding quantity (when these are used together, these total amounts) is 2-10 mass parts with respect to 100 mass parts of silica, Preferably it is 7-9 mass parts. The compounding temperature at the time of compounding these with a rubber component is 80-200 degreeC, for example, Preferably it is 110-180 degreeC.

  Further, when silica is used as the filler, it is further divalent such as monohydric alcohols such as ethanol, butanol and octanol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, pentaerythritol, polyether polyol and the like. You may mix | blend the above-mentioned alcohol, N-alkylamine, an amino acid, the liquid polybutadiene by which the molecular terminal was carboxyl-modified or amine-modified.

  When using a zinc oxide, the content in a rubber composition is 1-15 mass parts with respect to 100 mass parts of rubber components, Preferably it is 1-8 mass parts.

  When using a stearic acid, the content in a rubber composition is 0.5-10 mass parts with respect to 100 mass parts of rubber components, Preferably it is 1-5 mass parts.

  Examples of the crosslinking agent include sulfur, a sulfur-containing compound (for example, morpholine disulfide), a peroxide crosslinking agent (for example, dicumyl peroxide), a metal crosslinking agent (for example, zinc oxide), and an amine crosslinking agent (for example, hexagonal). Methylenediamine), an oxime crosslinking agent (for example, p-quinonedioxime, 4,4′-dibenzoylquinonedioxime) and the like, and sulfur is preferable. Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. Of these, powdered sulfur is preferred. For example, in the case where a crosslinked rubber composition described later is used for a tire member having a large amount of sulfur such as a belt member, insoluble sulfur is preferable. When sulfur is added to the rubber composition of the present invention, the content thereof in the rubber composition is, for example, 0.3 to 5 parts by mass, preferably 0.5 to 3 parts by mass with respect to 100 parts by mass of the rubber component. It is.

  When performing crosslinking (ie, vulcanization) using sulfur, it is preferable to use a vulcanization accelerator. Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators and sulfenamide-based vulcanization accelerators described in pages 412 to 413 of “Rubber Industry Handbook <Fourth Edition>” edited by the Japan Rubber Association. And guanidine vulcanization accelerators.

  Specific examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (BBS), N, N-dicyclohexene. Examples include xyl-2-benzothiazolylsulfenamide (DCBS), 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), and diphenylguanidine (DPG).

  For example, when carbon black is used as a filler, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (CBS) can be used as a vulcanization accelerator. BBS), N, N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS), dibenzothiazyl disulfide (MBTS) and diphenylguanidine (DPG) are preferably used in combination.

  For example, when a combination of silica and carbon black is used as a filler, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzo is used as a vulcanization accelerator. Any one of thiazolylsulfenamide (BBS), N, N-dicyclohexyl-2-benzothiazolylsulfenamide (DCBS), dibenzothiazyl disulfide (MBTS) and diphenylguanidine (DPG) can be used together preferable.

  The mass ratio of sulfur and vulcanization accelerator (sulfur / vulcanization accelerator) is not particularly limited, but is, for example, 2/1 to 1/2. EV vulcanization in which the mass ratio of sulfur / vulcanization accelerator, which is a method for improving heat resistance in a rubber member mainly composed of natural rubber, is 1 or less is preferably used in applications requiring improvement in heat resistance.

  As compounding agents other than those described above, various compounding agents usually used in the rubber field may be further compounded. Examples of such a compounding agent include oils; fatty acids other than stearic acid; Coumarone resin G-90 (softening point 80 to 100 ° C.) manufactured by Nikkaku Chemical, and process resin AC8 (softening point) manufactured by Kobe Oil Chemical Co., Ltd. 95 ° C.) coumarone / indene resin; terpene resins such as terpene resin, terpene / phenol resin, aromatic modified terpene resin; “Nikanol (registered trademark) HP-100” (softening point 105 to 125) manufactured by Mitsubishi Gas Chemical Company, Inc. ° C) xylene / formaldehyde resin; Rosin derivatives such as “Ester gum” series and “Neotor” series manufactured by Arakawa Chemical Co., Ltd .; Hydrogenated rosin derivatives; Novolac alkylphenol resins; Resole alkylphenol resins; C5 petroleum resins Liquid polybutadiene; and the like. Examples of the oil include process oil and vegetable oil. Examples of the process oil include paraffinic process oil, naphthenic process oil, aromatic process oil, and TDAE oil.

<Crosslinked rubber composition>
The crosslinked rubber composition of the present invention can be obtained by crosslinking the rubber composition of the present invention. Crosslinking is usually performed using a crosslinking agent (eg, sulfur or peroxide crosslinking agent). When using a rubber composition containing sulfur, crosslinking (ie, vulcanization) is usually performed by heat-treating the rubber composition. Moreover, when using the rubber composition containing a peroxide crosslinking agent, bridge | crosslinking is normally performed by heat-processing or light-irradiating the said rubber composition. The crosslinking is preferably vulcanized, and the crosslinked rubber composition of the present invention is preferably a vulcanized rubber composition. The heat treatment temperature is, for example, 120 to 180 ° C. The heat treatment may be usually performed at normal pressure or under pressure.

  The crosslinked rubber composition of the present invention can be suitably used for tires, for example. Examples of the tire include a pneumatic tire and a solid tire. Moreover, the crosslinked rubber composition of the present invention can be used for producing each member constituting a tire. Examples of such members include a tire belt including a steel cord coated with the crosslinked rubber composition of the present invention, a tire carcass including a carcass fiber cord coated with the crosslinked rubber composition of the present invention, and the present invention. Examples include tire sidewalls, tire inner liners, tire cap treads, tire undertreads, and the like that include the crosslinked rubber composition of the invention.

  The crosslinked rubber composition of the present invention can be used not only for the tires described above, but also as an anti-vibration rubber for automobiles such as engine mounts, strut mounts, bushes and exhaust hangers.

  Hereinafter, although a manufacture example and a test example are given and this invention is demonstrated concretely, this invention is not limited to these.

The rubber anti-aging substances and mesoporous silica used are as follows.
<Rubber aging prevention substances>
(A1) “Antigen 6C” (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Sumitomo Chemical Co., Ltd.
<Mesoporous silica>
(B1) “SILNOS 130” manufactured by ABCNANOTECH (BET specific surface area: 99.9 m ² / g, particle diameter (D ₅₀ ): 3.75 μm)
(B2) “SILNOS 230” manufactured by ABCNANOTECH (BET specific surface area: 28.4 m ² / g, particle diameter (D ₅₀ ): 3.24 μm)
(B3) “SILNOS 260OTS” manufactured by ABCNANOTECH (BET specific surface area: 49.4 m ² / g, particle diameter (D ₅₀ ): 5.35 μm)
(X1) “Silicia 710” manufactured by Fuji Silysia Co., Ltd. (BET specific surface area: 720 m ² / g, particle diameter (D ₅₀ ): 2.41 μm)
(X2) “Silicia 730” manufactured by Fuji Silysia Co., Ltd. (BET specific surface area: 555 m ² / g, particle diameter (D ₅₀ ): 3.25 μm)

The BET specific surface area of the above mesoporous silica is an actual measurement value measured under the following conditions.
Measuring device: BELSORP-mini (made by BEL Japan)
Pretreatment device: BELPREP-vacII (manufactured by Nippon BEL)
Test method: Nitrogen adsorption method Pretreatment method: Perform vacuum degassing at 120 ° C for 8 hours Measurement method: Measure adsorption desorption isotherm with nitrogen using constant volume method Adsorption temperature: 77K
Adsorbent: Nitrogen Specific surface area: Calculated by BET method

Production Example 1 (Manufacture of anti-aging agent for rubber)
A 500 mL beaker was charged with 20 parts by mass of mesoporous silica (B1), and 100 mL of methanol was added thereto to obtain a silica gel slurry. On the other hand, 20 parts by mass of an antiaging substance for rubber (A1) was charged into a 100 mL Erlenmeyer flask, and 60 mL of methanol was added thereto to obtain a methanol solution. Add a methanol solution of the rubber anti-aging agent (A1) to the silica gel slurry solution beaker prepared earlier, then wash the 100 mL Erlenmeyer flask containing this methanol solution with 20 mL of methanol, and add the cleaning solution to the beaker. Gave a mixture. The resulting mixture was stirred at 25 ° C. under air for 1 day. After completion of the stirring, the resulting mixture was dried by an evaporator to obtain an antiaging agent for rubber (1) as a gray solid.

Production Example 2 (Production of rubber anti-aging agent using mesoporous silica within the scope of the present invention)
An anti-aging agent for rubber (2) was obtained in the same manner as in Production Example 1, except that the mesoporous silica (B1) was changed to mesoporous silica (B2).

Production Example 3 (Production of anti-aging agent for rubber using mesoporous silica within the scope of the present invention)
A rubber anti-aging agent (3) was obtained in the same manner as in Production Example 1 except that the mesoporous silica (B1) was changed to the mesoporous silica (B3).

Production Example 4 (Production of anti-aging agent for rubber using mesoporous silica outside the scope of the present invention)
An anti-aging agent for rubber (Y1) was obtained in the same manner as in Production Example 1 except that the mesoporous silica (B1) was changed to the mesoporous silica (X1).

Production Example 5 (Production of anti-aging agent for rubber using mesoporous silica outside the scope of the present invention)
An anti-aging agent for rubber (Y2) was obtained in the same manner as in Production Example 1 except that mesoporous silica (B1) was changed to mesoporous silica (X2).

Production Example 6 (Production of basic rubber composition)
A 10-liter kneader is charged with 50 parts by mass of both commercially available natural rubber (product name “SMR-CV60”, standard Malaysian rubber) and butadiene rubber (product name “JSR BR01”, manufactured by JSR) and kneaded for 2 minutes. did. After adding the raw materials shown in Table 1 to the obtained kneaded product, the mixture was further kneaded for 10 minutes to obtain a basic rubber composition. The temperature for discharging the rubber composition from the kneader was 95 ° C.

Production Example 7 (Production of a crosslinked rubber composition not containing an antiaging substance for rubber)
163.5 parts by mass of the basic rubber composition obtained in Production Example 6, 3 parts by mass of zinc oxide, and a vulcanization accelerator (N-tert-butyl-2-benzothiazolesulfenamide (TBBS)) 0.8 A rubber composition was obtained by kneading mass parts and 1.5 mass parts of sulfur with an open roll machine having a roll set temperature of 60 ° C. The obtained rubber composition was subjected to hot press molding at 145 ° C. to obtain a crosslinked rubber composition (Z1) having a sheet shape having a width of 15.5 cm, a length of 16.0 cm, and a thickness of 2 mm. Incidentally, between 90% vulcanization of the measured rubber composition in conformity with JIS K 6300-2 to _(t c ₍₉₀₎₎ than the extended 5 minutes time and the vulcanization time.
The obtained crosslinked rubber composition (Z1) does not contain any rubber anti-aging substance and mesoporous silica.

Production Example 8 (Production of crosslinked rubber composition containing no mesoporous silica)
163.5 parts by mass of the basic rubber composition obtained in Production Example 6, 3 parts by mass of zinc oxide, and a vulcanization accelerator (N-tert-butyl-2-benzothiazolesulfenamide (TBBS)) 0.8 A rubber composition was obtained by kneading 3 parts by mass of sulfur, 1.5 parts by mass of sulfur, and 3 parts by mass of an antiaging substance for rubber (A1) with an open roll machine having a roll set temperature of 60 ° C. The obtained rubber composition was subjected to hot press molding at 145 ° C. to obtain a sheet-shaped crosslinked rubber composition (Z2) having a width of 15.5 cm, a length of 16.0 cm, and a thickness of 2 mm. Incidentally, between 90% vulcanization of the measured rubber composition in conformity with JIS K 6300-2 to _(t c ₍₉₀₎₎ than the extended 5 minutes time and the vulcanization time.
The obtained crosslinked rubber composition (Z2) contains a rubber anti-aging substance, but does not contain mesoporous silica.

Test Example 1 (Measurement of migration amount of anti-aging substance for rubber)
The amount of migration of the anti-aging agent for rubber of the crosslinked rubber composition (Z2) obtained in Production Example 8 was measured as follows.

  First, three blank sheets manufactured from a crosslinked rubber composition (Z1) not containing a rubber aging substance and three measurement sheets manufactured from a crosslinked rubber composition (Z2) containing a rubber aging substance The initial weight of each sheet was measured.

  FIG. 1 is a diagram for explaining a method for measuring the migration amount of a rubber anti-aging substance in a crosslinked rubber composition. After stacking the six sheets after the weight measurement (measurement sheets 1 to 3 and blank sheets 4 to 6), the entire laminate was wrapped with aluminum foil 7, and further wrapped with aluminum laminate 8 from above. . About 3 kg of weight 9 was placed on the aluminum foil and aluminum laminate package thus obtained.

The package on which the weight was placed was left in a thermostatic chamber at 25 ° C. for 6 days, then the aluminum foil and the aluminum laminate package were opened, each sheet was taken out, and the weight of each sheet was measured. The amount of migration of the rubber anti-aging substance was a change in weight from the initial weight of the blank sheet. The results are shown in Table 2 below.
In addition, as a result of separately extracting and quantifying the anti-aging agent for rubber from the crosslinked rubber composition of each sheet, it was confirmed that the weight change was caused by the migration of the anti-aging agent for rubber.

Production Example 9 (Production of the crosslinked rubber composition of the present invention)
163.5 parts by mass of the basic rubber composition obtained in Production Example 6, 3 parts by mass of zinc oxide, and a vulcanization accelerator (N-tert-butyl-2-benzothiazolesulfenamide (TBBS)) 0.8 A rubber composition is obtained by kneading 6 parts by mass of an anti-aging agent for rubber (1) obtained in Production Example 1 with an open roll machine having a roll set temperature of 60 ° C. I got a thing. The obtained rubber composition was subjected to hot press molding at 145 ° C. to obtain a crosslinked rubber composition (1) of the present invention having a sheet shape having a width of 15.5 cm, a length of 16.0 cm, and a thickness of 2 mm. . Incidentally, between 90% vulcanization of the measured rubber composition in conformity with JIS K 6300-2 to _(t c ₍₉₀₎₎ than the extended 5 minutes time and the vulcanization time.

Test Example 2 (Measurement of migration amount of anti-aging agent for rubber)
In the same manner as in Test Example 1 except that the crosslinked rubber composition (Z2) was changed to the crosslinked rubber composition (1) obtained in Production Example 9, the anti-aging agent for rubber of the crosslinked rubber composition (1) was used. The amount transferred was measured. The results are shown in Table 2 below.

Production Example 10 (Production of the crosslinked rubber composition of the present invention)
163.5 parts by mass of the basic rubber composition obtained in Production Example 6, 3 parts by mass of zinc oxide, and a vulcanization accelerator (N-tert-butyl-2-benzothiazolesulfenamide (TBBS)) 0.8 A rubber composition is obtained by kneading, by weight, 1.5 parts by mass of sulfur and 6 parts by mass of the anti-aging agent for rubber (2) obtained in Production Example 2 with an open roll machine having a roll set temperature of 60 ° C. I got a thing. The obtained rubber composition was subjected to hot press molding at 145 ° C. to obtain a crosslinked rubber composition (2) of the present invention having a sheet shape having a width of 15.5 cm, a length of 16.0 cm, and a thickness of 2 mm. . Incidentally, between 90% vulcanization of the measured rubber composition in conformity with JIS K 6300-2 to _(t c ₍₉₀₎₎ than the extended 5 minutes time and the vulcanization time.

Test Example 3 (Measurement of migration amount of anti-aging agent for rubber)
Except that the crosslinked rubber composition (Z2) was changed to the crosslinked rubber composition (2) obtained in Production Example 10, the same procedure as in Test Example 1 was conducted for the rubber anti-aging material for the crosslinked rubber composition (2). The amount transferred was measured. The results are shown in Table 2 below.

Production Example 11 (Production of the crosslinked rubber composition of the present invention)
163.5 parts by mass of the basic rubber composition obtained in Production Example 6, 3 parts by mass of zinc oxide, and a vulcanization accelerator (N-tert-butyl-2-benzothiazolesulfenamide (TBBS)) 0.8 A rubber composition is obtained by kneading 6 parts by mass of an anti-aging agent for rubber (3) obtained in Production Example 3 with an open roll machine having a roll set temperature of 60 ° C. I got a thing. The obtained rubber composition was subjected to hot press molding at 145 ° C. to obtain a crosslinked rubber composition (3) of the present invention having a sheet shape having a width of 15.5 cm, a length of 16.0 cm, and a thickness of 2 mm. . Incidentally, between 90% vulcanization of the measured rubber composition in conformity with JIS K 6300-2 to _(t c ₍₉₀₎₎ than the extended 5 minutes time and the vulcanization time.

Test Example 4 (Measurement of migration amount of anti-aging agent for rubber)
Except that the crosslinked rubber composition (Z2) was changed to the crosslinked rubber composition (3) obtained in Production Example 11, the same procedure as in Test Example 1 was carried out. The amount transferred was measured. The results are shown in Table 2 below.

Production Example 12 (Production of a crosslinked rubber composition containing mesoporous silica outside the scope of the present invention)
163.5 parts by mass of the basic rubber composition obtained in Production Example 6, 3 parts by mass of zinc oxide, and a vulcanization accelerator (N-tert-butyl-2-benzothiazolesulfenamide (TBBS)) 0.8 A rubber composition is obtained by kneading a mass part, 1.5 parts by mass of sulfur, and 6 parts by mass of an antioxidant for rubber (Y1) obtained in Production Example 4 with an open roll machine having a roll set temperature of 60 ° C. I got a thing. The obtained rubber composition was subjected to hot press molding at 145 ° C. to obtain a sheet-shaped crosslinked rubber composition (Z3) having a width of 15.5 cm, a length of 16.0 cm, and a thickness of 2 mm. Incidentally, between 90% vulcanization of the measured rubber composition in conformity with JIS K 6300-2 to _(t c ₍₉₀₎₎ than the extended 5 minutes time and the vulcanization time.
The obtained crosslinked rubber composition (Z3) contains mesoporous silica having a BET specific surface area outside the scope of the present invention.

Test Example 5 (Measurement of migration amount of anti-aging agent for rubber)
In the same manner as in Test Example 1 except that the crosslinked rubber composition (Z2) was changed to the crosslinked rubber composition (Z3) obtained in Production Example 12, the anti-aging material for rubber of the crosslinked rubber composition (Z3) was used. The amount transferred was measured. The results are shown in Table 2 below.

Production Example 13 (Production of a crosslinked rubber composition containing mesoporous silica outside the scope of the present invention)
163.5 parts by mass of the basic rubber composition obtained in Production Example 6, 3 parts by mass of zinc oxide, and a vulcanization accelerator (N-tert-butyl-2-benzothiazolesulfenamide (TBBS)) 0.8 A rubber composition is prepared by kneading a mass part, 1.5 parts by mass of sulfur, and 6 parts by mass of an antioxidant for rubber (Y2) obtained in Production Example 5 with an open roll machine having a roll set temperature of 60 ° C. I got a thing. The obtained rubber composition was subjected to hot press molding at 145 ° C. to obtain a crosslinked rubber composition (Z4) having a sheet shape having a width of 15.5 cm, a length of 16.0 cm, and a thickness of 2 mm. Incidentally, between 90% vulcanization of the measured rubber composition in conformity with JIS K 6300-2 to _(t c ₍₉₀₎₎ than the extended 5 minutes time and the vulcanization time.
The obtained crosslinked rubber composition (Z4) contains mesoporous silica having a BET specific surface area outside the scope of the present invention.

Test Example 6 (Measurement of migration amount of anti-aging agent for rubber)
Except for changing the crosslinked rubber composition (Z2) to the crosslinked rubber composition (Z4) obtained in Production Example 13, in the same manner as in Test Example 1, the anti-aging agent for rubber of the crosslinked rubber composition (Z4) was obtained. The amount transferred was measured. The results are shown in Table 2 below.

  As shown in Table 2, the crosslinked rubber compositions (1) to (3) of the present invention include a crosslinked rubber composition (Z2) containing no mesoporous silica and mesoporous silica having a BET specific surface area outside the scope of the present invention. Compared with the crosslinked rubber compositions (Z3) and (Z4) to be contained, the migration amount of the antiaging substance for rubber is small. From this result, it can be seen that the crosslinked rubber composition of the present invention has the effect of inhibiting the anti-aging of rubber, and the anti-aging effect is sufficiently maintained.

Production Example 14 (Production of the crosslinked rubber composition of the present invention)
The crosslinked rubber composition obtained by the following first step and second step is suitable for undertread.
<First step>
(Procedure 1)
Using a Banbury mixer (600 mL Laboplast Mill manufactured by Toyo Seiki Co., Ltd.), 100 parts by mass of styrene / butadiene copolymer rubber (“SBR # 1502” manufactured by Sumitomo Chemical Co., Ltd.), ISAF-HM (“Asahi # 80” manufactured by Asahi Carbon Co., Ltd.) 35 parts by mass, 2 parts by mass of stearic acid, 3 parts by mass of zinc oxide, 8 parts by mass of the anti-aging agent for rubber (1), and 2 parts by mass of wax (“OZOACE-0355” manufactured by Nippon Seiwa Co., Ltd.) A rubber composition is obtained by kneading within a range of ˜175 ° C. for 5 minutes at a mixer rotational speed of 50 rpm.
(Procedure 2)
In the range of 60 to 80 ° C. with an open roll machine, the total amount of the rubber composition obtained in Procedure 1, 2 parts by mass of N-cyclohexyl-2-benzothiazole sulfenamide (CBS) as a vulcanization accelerator, By kneading 0.5 part by mass of diphenylguanidine (DPG) as a vulcanization accelerator, 0.8 part by mass of dibenzothiazyl disulfide (MBTS) as a vulcanization accelerator and 1 part by mass of sulfur, a rubber composition is obtained. can get.
<Second step>
A crosslinked rubber composition is obtained by heat-treating the rubber composition obtained in the first step (procedure 2) at 145 ° C.

Production Example 15 (Production of the crosslinked rubber composition of the present invention)
The crosslinked rubber composition obtained by the following first step and second step is suitable for a belt.
<First step>
(Procedure 1)
Using a Banbury mixer (600 mL Lab Plast Mill manufactured by Toyo Seiki), 100 parts by mass of commercially available natural rubber (RSS # 1), 45 parts by mass of HAF (“Asahi # 70” manufactured by Asahi Carbon Co., Ltd.), 3 parts by mass of stearic acid, 5 parts by mass of zinc oxide, 10 parts by mass of hydrous silica (“Nipsil (registered trademark) AQ” manufactured by Tosoh Silica), 16 parts by mass of the anti-aging agent for rubber (1), 2 parts by mass of resorcin and 2 parts by mass of cobalt naphthenate The rubber composition is obtained by kneading the parts within a range of 160 to 175 ° C. for 5 minutes at a mixer rotational speed of 50 rpm.
(Procedure 2)
The total amount of the rubber composition obtained in Procedure 1 within the range of 60 to 80 ° C. with an open roll machine, and 1 mass of N, N-dicyclohexyl-2-benzothiazolesulfenamide (DCBS) as a vulcanization accelerator. A rubber composition is obtained by kneading 3 parts by mass, 6 parts by mass of sulfur and 3 parts by mass of a methoxylated methylol melamine resin (“SUMIKANOL 507AP” manufactured by Sumitomo Chemical Co., Ltd.).
<Second step>
A crosslinked rubber composition is obtained by heat-treating the rubber composition obtained in the first step (procedure 2) at 145 ° C.

Production Example 16 (Production of the crosslinked rubber composition of the present invention)
The crosslinked rubber composition obtained by the following first step and second step is suitable for an inner liner.
<First step>
(Procedure 1)
Using a Banbury mixer (600 mL Laboplast Mill, manufactured by Toyo Seiki Co., Ltd.), 100 parts by mass of halogenated butyl rubber (“Br-IIR2255” manufactured by ExxonMobil), 60 parts by mass of GPF, 1 part by mass of stearic acid, 3 parts by mass of zinc oxide, A rubber composition is obtained by kneading 10 parts by weight of paraffin oil (“Diana Process Oil” manufactured by Idemitsu Kosan Co., Ltd.) within a range of 160 to 175 ° C. for 5 minutes at a mixer rotational speed of 50 rpm.
(Procedure 2)
The total amount of the rubber composition obtained in the procedure 1 in the range of 60 to 80 ° C. in an open roll machine, 2 parts by mass of the rubber anti-aging agent (1), and dibenzothiazyl disulfide (MBTS) as a vulcanization accelerator A rubber composition is obtained by kneading 1 part by mass and 2 parts by mass of sulfur.
<Second step>
The kneaded product obtained in the first step (procedure 2) is heat-treated at 145 ° C. to obtain a crosslinked rubber composition.

Production Example 17 (Production of the crosslinked rubber composition of the present invention)
The crosslinked rubber composition obtained by the following first step and second step is suitable for sidewalls.
<First step>
(Procedure 1)
Using a Banbury mixer (600 mL Laboplast Mill, manufactured by Toyo Seiki Co., Ltd.), 40 parts by mass of commercially available natural rubber (RSS # 3), 60 parts by mass of polybutadiene rubber (“BR150B” manufactured by Ube Industries, Ltd.), 50 parts by mass of FEF, and stearic acid 2 0.5 parts by mass, 3 parts by mass of zinc oxide, 16 parts by mass of the rubber anti-aging agent (1), 10 parts by mass of aromatic oil (“NC-140” manufactured by Cosmo Oil Co., Ltd.) and wax (Ouchi Shinsei Chemical Co., Ltd.) A rubber composition is obtained by kneading 2 parts by mass of “Sannok (registered trademark) wax”) in a range of 160 to 175 ° C. for 5 minutes at a mixer rotation speed of 50 rpm.
(Procedure 2)
N-tert-butyl-2-benzothiazolylsulfenamide (BBS) 0.75 which is the total amount of the rubber composition obtained in the procedure 1 and vulcanization accelerator within the range of 60 to 80 ° C. with an open roll machine. A rubber composition is obtained by kneading mass parts and 1.5 mass parts of sulfur.
<Second step>
A crosslinked rubber composition is obtained by heat-treating the rubber composition obtained in the first step (procedure 2) at 145 ° C.

Production Example 18 (Production of the crosslinked rubber composition of the present invention)
The crosslinked rubber composition obtained by the following first step and second step is suitable for carcass.
<First step>
(Procedure 1)
Using a Banbury mixer (600 mL Laboplast Mill, manufactured by Toyo Seiki Co., Ltd.), 70 parts by mass of commercially available natural rubber (TSR20), 30 parts by mass of styrene / butadiene copolymer rubber (“SBR # 1502” manufactured by Sumitomo Chemical Co., Ltd.), N339 (Mitsubishi) Chemical Co., Ltd.) 60 parts by mass, stearic acid 2 parts by mass, zinc oxide 5 parts by mass, process oil (“Diana Process PS32” by Idemitsu Kosan Co., Ltd.) 7 parts by mass within the range of 160 to 175 ° C. for 5 minutes, By kneading at a mixer rotational speed of 50 rpm, a rubber composition is obtained.
(Procedure 2)
The total amount of the rubber composition obtained in Procedure 1 within the range of 60 to 80 ° C. with an open roll machine, and 1 part by mass of N-tert-butyl-2-benzothiazolylsulfenamide (BBS) as a vulcanization accelerator A rubber composition is obtained by kneading 3 parts by mass of sulfur and 8 parts by mass of the anti-aging agent for rubber (1).
<Second step>
A vulcanized rubber composition is obtained by heat-treating the rubber composition obtained in the first step (procedure 2) at 145 ° C.

Production Example 19 (Production of the crosslinked rubber composition of the present invention)
The crosslinked rubber composition obtained by the following first step and second step is suitable for cap treads.
<First step>
(Procedure 1)
Using a Banbury mixer (600 mL Laboplast Mill, manufactured by Toyo Seiki Co., Ltd.), 100 parts by mass of styrene / butadiene copolymer rubber (“SBR # 1500” manufactured by JSR), silica (“Ultrasil (registered trademark) VN3-G manufactured by Degussa) 78.4 parts by mass, carbon black (“N-339” manufactured by Mitsubishi Chemical Corporation), 6.4 parts by mass, silane coupling agent (bis (3-triethoxysilylpropyl) tetrasulfide, “Si— 69 ") 6.4 parts by mass, process oil (" NC-140 "manufactured by Cosmo Oil Co., Ltd.) 47.6 parts by mass, rubber anti-aging agent (1) 12 parts by mass, zinc oxide 2 parts by mass, stearic acid 2 The mass part is kneaded in the range of 70 to 120 ° C. for 5 minutes at a mixer rotational speed of 80 rpm, and subsequently in the range of 70 to 120 ° C. for 5 minutes for 100 r. By kneading in a mixer rotation speed of m, the rubber composition is obtained.
(Procedure 2)
In the range of 30 to 80 ° C. with an open roll machine, the total amount of the rubber composition obtained in the procedure 1, 1 part by mass of N-cyclohexyl-2-benzothiazolesulfenamide (CBS) as a vulcanization accelerator, By kneading 1 part by mass of diphenylguanidine (DPG) as a vulcanization accelerator, 1.5 parts by mass of wax (“Sunnock (registered trademark) N” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) and 1.4 parts by mass of sulfur A rubber composition is obtained.
<Second step>
A crosslinked rubber composition is obtained by heat-treating the rubber composition obtained in the first step (procedure 2) at 160 ° C.

Production Example 20 (Production of the crosslinked rubber composition of the present invention)
Production Example 19 is the same as Production Example 19 except that instead of styrene-butadiene copolymer rubber (“SBR # 1500” manufactured by JSR), solution polymerization SBR (“ASAPrene (registered trademark)” manufactured by Asahi Kasei Chemicals) is used. Similarly, a crosslinked rubber composition is obtained. The resulting crosslinked rubber composition is suitable for cap treads.

Production Example 21 (Production of the crosslinked rubber composition of the present invention)
In Production Example 19, instead of “SBR # 1500” manufactured by JSR as styrene / butadiene copolymer rubber, “SBR # 1712” manufactured by JSR was used, and the amount of process oil used was changed to 21 parts by mass. A crosslinked rubber composition is obtained in the same manner as in Production Example 19 except that the timing of charging zinc is changed to Procedure 2. The resulting crosslinked rubber composition is suitable for cap treads.

  The crosslinked rubber composition of the present invention has a sufficient effect of the anti-aging agent for rubber contained therein and is suitable for various applications (for example, tires).

1,2,3 Measurement sheet produced from a crosslinked rubber composition containing an anti-aging substance for rubber 4,5,6 Blank sheet produced from a crosslinked rubber composition not containing an anti-aging substance for rubber 7 Aluminum foil 8 Aluminum laminate 9 Weight

Claims (10)

(A) an anti-aging agent for rubber containing mesoporous silica having a BET specific surface area of 20 to ²⁰⁰ m ² / g and an anti-aging agent for rubber, and (b) a rubber composition containing a rubber component. (A) an anti-aging agent for rubber containing mesoporous silica having a BET specific surface area of 20 to ²⁰⁰ m ² / g and an anti-aging agent for rubber, and (b) a rubber composition obtained by kneading a rubber component. .   The rubber composition according to claim 1 or 2, wherein a rubber anti-aging substance is supported on the mesoporous silica. The rubber composition according to any one of claims 1 to 3, wherein the rubber anti-aging substance is a compound represented by the formula (I).

(In formula (I), R ¹ represents a hydrogen atom or an alkyl group having 1 to 13 carbon atoms.)   The rubber composition according to any one of claims 1 to 4, wherein the mesoporous silica content is 1 to 50 parts by mass with respect to 10 parts by mass of the rubber anti-aging agent.   The crosslinked rubber composition obtained by bridge | crosslinking the rubber composition as described in any one of Claims 1-5.   A tire comprising the crosslinked rubber composition according to claim 6.   A sidewall, inner liner, cap tread or under tread for a tire comprising the crosslinked rubber composition according to claim 6.   A tire belt comprising a steel cord coated with the crosslinked rubber composition according to claim 6.   A tire carcass comprising a carcass fiber cord coated with the crosslinked rubber composition according to claim 6.

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