JP2013173893A - Rubber composition for tire and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a rubber composition that combines a low exothermic property and abrasion resistance; and a pneumatic tire using the rubber composition.SOLUTION: A rubber composition for a tire combines, based on 100 pts.mass of a rubber component including a modified diene-based rubber that has an interaction with silica: 1-50 pts.mass of carbon black containing silica; 15-90 pts.mass of silica; and 0-30 pts.mass of carbon black, and the total content of the carbon black containing silica, the silica, and the carbon black is 20-100 pts.mass.

Description

The present invention relates to a rubber composition for tires and a pneumatic tire using the same.

Conventionally, reinforcing fillers such as carbon black and silica have been blended in tire rubber compositions for the purpose of reinforcing rubber (for example, Patent Document 1). When carbon black is blended, a rubber composition having good processability and excellent durability can be obtained, but the heat build-up becomes high and the rolling resistance of the tire increases. On the other hand, when silica is uniformly dispersed in a rubber composition and blended, silica exothermic rubber has been attracting attention because of its low heat build-up and reduced rolling resistance.

Recently, low heat generation has been required not only for tires with a high tread ratio, but also for other components such as base treads, but replacing carbon black with silica has the effect of reducing rolling resistance. On the other hand, there is a problem that the reinforcing property is lowered. Especially for base treads, carbon black with a large particle size is usually used in many cases, so the effect of reducing the rolling resistance when changing to silica is small, but the breaking strength, elongation at break, etc. Degradation characteristics will be reduced.

In this way, low rolling resistance performance and high reinforcement are generally in a trade-off relationship, but one of the factors is that silica dispersibility is insufficient, so silica performance is maximized. It is possible that it has not been demonstrated. In addition, blending of carbon black and silica has been studied to improve performance such as destructive properties. However, it is inevitable that low heat build-up becomes insufficient due to the incorporation of carbon black. As described above, since it is generally difficult to achieve both low exothermic properties and fracture characteristics, it is desired to improve these performances in a balanced manner.

Japanese Patent Laid-Open No. 2001-164051

An object of the present invention is to solve the above-mentioned problems, and to provide a rubber composition having both low heat buildup and fracture characteristics, and a pneumatic tire using the rubber composition.

In the present invention, 1 to 50 parts by mass of silica-containing carbon black, 15 to 90 parts by mass of silica, and 0 to 0 of carbon black with respect to 100 parts by mass of a rubber component containing a modified diene rubber having an interaction with silica. It is related with the rubber composition for tires which mix | blends-30 mass parts, and the total content of this silica containing carbon black, this silica, and this carbon black is 20-100 mass parts.

The rubber component preferably further includes natural rubber and butadiene rubber.
The silica content in 100% by mass of the silica-containing carbon black is preferably 0.1 to 70% by mass.

Furthermore, it is preferable to include a silane coupling agent having a mercapto group.
The rubber composition is preferably used as a rubber composition for a base tread.
The present invention also relates to a pneumatic tire having a base tread produced using the rubber composition described above.

According to the present invention, a predetermined amount of silica-containing carbon black, silica, and carbon black is blended with a rubber component including a modified diene rubber having an interaction with silica, and the total amount thereof is also set to a predetermined amount. Since the rubber composition for tires is adjusted, the performance balance between low heat buildup and fracture characteristics can be improved, and both of these performances can be achieved. Therefore, it can be suitably applied to a rubber composition for base treads.

The graph showing the relationship between the rolling resistance index measured by the Example and the comparative example, and fracture energy.

The rubber composition for tires of the present invention contains a predetermined amount of each component of silica-containing carbon black, silica, and carbon black in a rubber component containing a modified diene rubber having an interaction with silica. The total amount is adjusted to a predetermined amount. By mixing and kneading silica-containing carbon black and silica, uniform dispersion of silica, which is difficult with silica alone, is promoted by silica-containing carbon black. Accordingly, since the filler is sufficiently dispersed, the low exothermic property that is the merit of silica can be obtained, and at the same time, the lack of destructive property that is a demerit can be compensated, and both the low exothermic property and the destructive property can be achieved. .

In the present invention, a modified diene rubber having an interaction with silica is used as the rubber component. For example, a compound having a functional group that interacts with silica (preferably a functional group containing at least one atom selected from the group consisting of nitrogen, oxygen, and silicon) at one end of a diene rubber (modified) End-modified diene rubber modified with the agent 1), main-chain modified diene rubber having the above functional group in the main chain, main chain end-modified diene rubber having the above functional group in the main chain and terminal (for example, And a main chain terminal-modified diene rubber having the functional group in the main chain and at least one terminal modified with the modifier 1).

Examples of the functional group include amino group, amide group, alkoxysilyl group, isocyanate group, imino group, imidazole group, urea group, ether group, carbonyl group, oxycarbonyl group, sulfide group, disulfide group, sulfonyl group, sulfinyl group. Thiocarbonyl group, ammonium group, imide group, hydrazo group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group and the like. These functional groups may have a substituent. Among these, from the viewpoint of fuel economy and destructive properties, 1, 2 or 3 amino groups (preferably 1 or 2 hydrogen atoms of primary amino groups are substituted with alkyl groups having 1 to 6 carbon atoms. A secondary or tertiary amino group), an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), or an alkoxysilyl group (preferably an alkoxysilyl group having 1 to 6 carbon atoms) is preferable.

Examples of the diene rubber into which the functional group is introduced (polymer constituting the skeleton of the modified diene rubber) include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), and styrene butadiene rubber (SBR). And diene polymers such as styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). Of these, SBR is preferable. In the following, a modified diene rubber in which the polymer constituting the skeleton of the modified diene rubber is SBR is also referred to as a modified SBR.

Examples of the modifier 1 include 3-glycidoxypropyltrimethoxysilane, (3-triethoxysilylpropyl) tetrasulfide, 1- (4-N, N dimethylaminophenyl) -1-phenylethylene, 1,1. -Dimethoxytrimethylamine, 1,2-bis (trichlorosilyl) ethane, 1,3,5-tris (3-triethoxysilylpropyl) isocyanurate, 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate 1,3-dimethyl-2-imidazolidinone, 1,3-propanediamine, 1,4-diaminobutane, 1- [3- (triethoxysilyl) propyl] -4,5-dihydroimidazole, 1-glycidyl -4- (2-pyridyl) piperazine, 1-glycidyl-4-phenylpiperazine, 1-glyci Ru-4-methylpiverazine, 1-glycidyl-4-methylhomopiverazine, 1-glycidylhexamethyleneimine, 11-aminoundecyltriethoxysilane, 11-aminoundecyltrimethoxysilane, 1-benzyl-4-glycidyl Piperazine, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (4-morpholinodithio) benzothiazole, 2- (6-aminoethyl) -3-aminopropyltrimethoxysilane, 2- (tri Ethoxysilylethyl) pyridine, 2- (trimethoxysilylethyl) pyridine, 2- (2-pyridylethyl) thiopropyltrimethoxysilane, 2- (4-pyridylethyl) thiopropyl trimethoxysilane, 2,2-diethoxy -1,6-diaza-2-silacyclooctane, , 2-Dimethoxy-1,6-diaza-2-silacyclooctane, 2,3-dichloro-1,4-naphthoquinone, 2,4-dinitrobenzenesulfonyl chloride, 2,4-tolylene diisocyanate, 2- ( 4-pyridylethyl) triethoxysilane, 2- (4-pyridylethyl) trimethoxysilane, 2-cyanoethyltriethoxysilane, 2-tributylstannyl-1,3-butadiene, 2- (trimethoxysilylethyl) pyridine, 2-vinylpyridine, 2- (4-pyridylethyl) triethoxysilane, 2- (4-pyridylethyl) trimethoxysilane, 2-laurylthioethylphenylketone, 3- (1-hexamethyleneimino) propyl (triethoxy) Silane, 3- (1,3-dimethylbutylidene) aminopropyltriethoxy Silane, 3- (1,3-dimethylbutylidene) aminopropyltrimethoxysilane, 3- (2-aminoethylaminopropyl) trimethoxysilane, 3- (m-aminophenoxy) propyltrimethoxysilane, 3- (N , N-dimethylamino) propyltriethoxysilane, 3- (N, N-dimethylamino) propyltrimethoxysilane, 3- (N-methylamino) propyltriethoxysilane, 3- (N-methylamino) propyltrimethoxy Silane, 3- (N-allylamino) propyltrimethoxysilane, 3,4-diaminobenzoic acid, 3-aminopropyldimethylethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyl Tris (methoxydiethoxy) silane, 3-a Nopropyldiisopropylethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-diethylaminopropyltrimethoxy Silane, 3-diethoxy (methyl) silylpropyl succinic anhydride, 3- (N, N-diethylaminopropyl) triethoxysilane, 3- (N, N-diethylaminopropyl) trimethoxysilane, 3- (N, N-dimethyl) Aminopropyl) diethoxymethylsilane, 3- (N, N-dimethylaminopropyl) triethoxysilane, 3- (N, N-dimethylaminopropyl) trimethoxysilane, 3-triethoxysilylpropyl succinic anhydride, 3- G Ethoxysilylpropyl acetic anhydride, 3-triphenoxysilylpropyl succinic anhydride, 3-triphenoxysilylpropyl acetic anhydride, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-hexamethyleneiminopropyltriethoxysilane, 3-mercaptopropyl Trimethoxysilane, (3-triethoxysilylpropyl) diethylenetriamine, (3-trimethoxysilylpropyl) diethylenetriamine, 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4′- (Imidazol-1-yl) -acetophenone, 4- [3- (N, N-diglycidylamino) propyl] morpholine, 4-glycidyl-2,2,6,6-tetramethylpiberidinyloxy, 4- Ami Nobutyltriethoxysilane, 4-vinylpyridine, 4-morpholinoacetophenone, 4-morpholinobenzophenone, m-aminophenyltrimethoxysilane, N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1 -Propanamine, N- (1,3-dimethylbutylidene) -3- (trimethoxysilyl) -1-propanamine, N- (1-methylethylidene) -3- (triethoxysilyl) -1-propanamine N- (2-aminoethyl) -3-aminopropylmethyldiethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyl Triethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2- Minoethyl) -11-aminoundecyltriethoxysilane, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane, N- (2-aminoethyl) -3-aminoisobutylmethyldiethoxysilane, N- (2-aminoethyl) -3-aminoisobutylmethyldimethoxysilane, N- (3-diethoxymethylsilylpropyl) succinimide, N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole, N- (3 -Triethoxysilylpropyl) pyrrole, N- (3-trimethoxysilylpropyl) pyrrole, N-3- [amino (polypropyleneoxy)] aminopropyltrimethoxysilane, N- [5- (triethoxysilyl) -2- Aza-1-oxopentyl] caprolactam, N- [5- (trimeth) Sisilyl) -2-aza-1-oxopentyl] caprolactam, N- (6-aminohexyl) aminomethyltriethoxysilane, N- (6-aminohexyl) aminomethyltrimethoxysilane, N-allyl-aza-2, 2-diethoxysilacyclopentane, N-allyl-aza-2,2-dimethoxysilacyclopentane, N- (cyclohexylthio) phthalimide, Nn-butyl-aza-2,2-diethoxysilacyclopentane, N -N-butyl-aza-2,2-dimethoxysilacyclopentane, N, N, N ', N'-tetraethylaminobenzophenone, N, N, N', N'-tetramethylthiourea, N, N, N ' , N′-tetramethylurea, N, N′-ethyleneurea, N, N′-diethylaminobenzophenone, N, N′-diethylaminobenzofe Non, N, N′-diethylaminobenzofuran, methyl N, N′-diethylcarbamate, N, N′-diethylurea, (N, N-diethyl-3-aminopropyl) triethoxysilane, (N, N-diethyl) -3-aminopropyl) trimethoxysilane, N, N-dioctyl-N′-triethoxysilylpropylurea, N, N-dioctyl-N′-trimethoxysilylpropylurea, methyl N, N-diethylcarbamate, N , N-diglycidylcyclohexylamine, N, N-dimethyl-o-toluidine, N, N-dimethylaminostyrene, N, N-diethylaminopropylacrylamide, N, N-dimethylaminopropylacrylamide, N-ethylaminoisobutyltriethoxy Silane, N-ethylaminoisobutyltrimethoxysilane N-ethylaminoisobutylmethyldiethoxysilane, N-oxydiethylene-2-benzothiazolesulfenamide, N-cyclohexylaminopropyltriethoxysilane, N-cyclohexylaminopropyltrimethoxysilane, N-methylaminopropylmethyldimethoxysilane, N-methylaminopropylmethyldiethoxysilane, N-vinylbenzylazacycloheptane, N-phenylpyrrolidone, N-phenylaminopropyltriethoxysilane, N-phenylaminopropyltrimethoxysilane, N-phenylaminomethyltriethoxysilane, N-phenylaminomethyltrimethoxysilane, n-butylaminopropyltriethoxysilane, n-butylaminopropyltrimethoxysilane, N-methylaminopropylto Riethoxysilane, N-methylaminopropyltrimethoxysilane, N-methyl-2-piperidone, N-methyl-2-pyrrolidone, N-methyl-ε-caprolactam, N-methylindolinone, N-methylpyrrolidone, p- (2-dimethylaminoethyl) styrene, p-aminophenyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, (aminoethylamino) -3-isobutyldiethoxysilane, ( Aminoethylamino) -3-isobutyldimethoxysilane, (aminoethylaminomethyl) phenethyltriethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, acrylic acid, diethyl adipate, acetamidopropyltrimethoxysilane, amino Phenyltrimethoxysilane, aminobenzophenone, ureidopropyltriethoxysilane, ureidopropyltrimethoxysilane, ethylene oxide, octadecyldimethyl (3-trimethoxysilylpropyl) ammonium chloride, glycidoxypropyltriethoxysilane, glycidoxypropyltrimethoxysilane , Glycerol tristearate, chlorotriethoxysilane, chloropropyltriethoxysilane, chloropolydimethylsiloxane, chloromethyldiphenoxysilane, diallyldiphenyltin, diethylaminomethyltriethoxysilane, diethylaminomethyltrimethoxysilane, diethyl (glycidyl) amine, diethyl Dithiocarbamic acid 2-benzothiazoyl ester, diethoxydichlorosilane, (Cyclohexylaminomethyl) triethoxysilane, (cyclohexylaminomethyl) trimethoxysilane, diglycidylpolysiloxane, dichlorodiphenoxysilane, dicyclohexylcarbodiimide, divinylbenzene, diphenylcarbodiimide, diphenylcyanamide, diphenylmethane diisocyanate, diphenoxymethylchlorosilane, dibutyldichlorotin , Dimethyl (acetoxy-methylsiloxane) polydimethylsiloxane, dimethylaminomethyltriethoxysilane, dimethylaminomethyltrimethoxysilane, dimethyl (methoxy-methylsiloxane) polydimethylsiloxane, dimethylimidazolidinone, dimethylethyleneurea, dimethyldichlorosilane, Dimethylsulfomoyl chloride, silsesquioxa , Sorbitan trioleate, sorbitan monolaurate, titanium tetrakis (2-ethylhexoxide), tetraethoxysilane, tetraglycidyl-1, 3-bisaminomethylcyclohexane, tetraphenoxysilane, tetramethylthiuram disulfide, tetra Methoxysilane, triethoxyvinylsilane, tris (3-trimethoxysilylpropyl) cyanurate, triphenyl phosphate, triphenoxychlorosilane, triphenoxymethylsilicon, triphenoxymethylsilane, carbon dioxide, bis (triethoxysilylpropyl) amine, bis ( Trimethoxysilylpropyl) amine, bis [3- (triethoxysilyl) propyl] ethylenediamine, bis [3- (trimethoxysilyl) propyl] Tylenediamine, bis [3- (triethoxysilyl) propyl] urea, bis [(trimethoxysilyl) propyl] urea, bis (2-hydroxymethyl) -3-aminopropyltriethoxysilane, bis (2-hydroxymethyl) -3-aminopropyltrimethoxysilane, bis (2-ethylhexanoate) tin, bis (2-methylbutoxy) methylchlorosilane, bis (3-triethoxysilylpropyl) tetrasulfide, bisdiethylaminobenzophenone, bisphenol A diglycidyl Ether, bisphenoxyethanol fluorenediglycidyl ether, bis (methyldiethoxysilylpropyl) amine, bis (methyldimethoxysilylpropyl) -N-methylamine, hydroxymethyltriethoxysilane, vinyl (2-ethylhexyloxy) silane, vinylbenzyldiethylamine, vinylbenzyldimethylamine, vinylbenzyltributyltin, vinylbenzylpiperidine, vinylbenzylpyrrolidine, pyrrolidine, phenylisocyanate, phenylisothiocyanate, (phenylaminomethyl) methyldimethoxysilane, (Phenylaminomethyl) methyldiethoxysilane, phthalic acid amide, hexamethylene diisocyanate, benzylidene aniline, polydiphenylmethane diisocyanate, polydimethylsiloxane, methyl-4-pyridyl ketone, methylcaprolactam, methyltriethoxysilane, methyltriphenoxysilane , Methyl lauryl thiopropionate, silicon tetrachloride, dimethylaminopropyl bromide, diethylamino bromide Nopropyl, dipropylaminopropyl bromide, dimethylaminopropyl chloride, diethylaminopropyl chloride, dipropylaminopropyl chloride and the like. Among these, 3- (N, N-dimethylamino) propyltrimethoxysilane, 3- (N, N-diethylamino) propyltrimethoxysilane, 3- (N, N-dimethyl) because of the large performance improvement effect. Amino) propyltriethoxysilane, 3- (N, N-diethylamino) propyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (4-pyridylethyl) triethoxysilane, 1- [3- (tri Ethoxysilyl) propyl] -4,5-dihydroimidazole, silicon tetrachloride, dimethylaminopropyl bromide, diethylaminopropyl bromide, dipropylaminopropyl bromide, dimethylaminopropyl chloride, diethylaminopropyl chloride, dipropylaminopropyl chloride preferable. These may be used alone or in combination of two or more.

Examples of methods for modifying the diene rubber with the modifier 1 include conventionally known methods such as the methods described in JP-B-6-53768, JP-B-6-57767, JP-T2003-514078, and the like. Can be used. For example, the diene rubber and the modifier 1 may be brought into contact. After the diene rubber is synthesized by anionic polymerization, a predetermined amount of the modifier 1 is added to the polymer rubber solution, and the polymerization terminal of the diene rubber is added. Examples thereof include a method of reacting (active terminal) with the modifier 1 and a method of adding the modifier 1 to the diene rubber solution and reacting it.

The main chain-modified diene rubber can be polymerized using a conventionally known method. For example, it is obtained by polymerizing using a monomer having the above functional group (for example, p-methoxystyrene etc.) as a part of the monomer used for polymerization. The main chain terminal-modified diene rubber can be obtained, for example, by bringing the main chain-modified diene rubber into contact with the modifier 1.

Among the above-mentioned modified diene rubbers, at least one end of the diene rubber is modified with the above modifier 1 because of its high effect of improving fuel economy and breaking properties (functional group interacting with silica). A terminal-modified diene rubber having at least one terminal is preferable, and a terminal-modified diene rubber having both terminals modified with the modifier 1 (having functional groups that interact with silica at both terminals) is more preferable. Further, a both-end modified SBR in which both ends are modified with the modifying agent 1 is more preferable.

As the both-end-modified diene rubber, a modified diene polymer (hereinafter also referred to as a modified diene polymer) obtained by reacting the following (A) and (B) is particularly preferable.

（式（１）中、Ｒ^１１及びＲ^１２は、同一若しくは異なって、水素原子、分岐若しくは非分岐のアルキル基、分岐若しくは非分岐のアリール基、分岐若しくは非分岐のアルコキシ基、分岐若しくは非分岐のシリルオキシ基、分岐若しくは非分岐のアセタール基、カルボキシル基（−ＣＯＯＨ）、メルカプト基（−ＳＨ）又はこれらの誘導体を示す。Ａは、分岐若しくは非分岐のアルキレン基、分岐若しくは非分岐のアリーレン基又はこれらの誘導体を示す。） (A): an active conjugated diene polymer having an alkali metal end obtained by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in the presence of (C) below (B): functional group Modifier (C) having: a chemical species obtained by reacting a compound represented by the following formula (1) with an organic alkali metal compound

(In Formula (1), R ¹¹ and R ¹² are the same or different and each represents a hydrogen atom, a branched or unbranched alkyl group, a branched or unbranched aryl group, a branched or unbranched alkoxy group, a branched or unbranched group. A silyloxy group, a branched or unbranched acetal group, a carboxyl group (—COOH), a mercapto group (—SH) or a derivative thereof, wherein A represents a branched or unbranched alkylene group, a branched or unbranched arylene group Or these derivatives are shown.)

In order to perform the polymerization reaction using the chemical species (C) obtained by reacting the compound represented by the above formula (1) and the organic alkali metal compound as a polymerization initiator, the polymer chain obtained by the polymerization reaction (above (A) (Active conjugated diene polymer)) has both ends as living polymer ends. Therefore, both ends of the active conjugated diene polymer (A) can be modified with the modifier (B), and the modified diene polymer obtained by modifying both ends of (A) with the above (B) Compared with the case where only one end is modified, excellent fuel economy and breaking characteristics can be obtained, and these performances can be improved in a well-balanced manner.

The above (A) is obtained by using the above (C) as a polymerization initiator, and the polymer chain extends in two directions by the polymerization reaction, and there are two living polymer terminals. Can be introduced. Therefore, by blending the modified diene polymer obtained by reacting the above (A) and (B) together with silica-containing carbon black and silica, a rubber composition having excellent balance between fuel efficiency and fracture characteristics. A thing is obtained.

(A) is an active conjugated diene polymer having an alkali metal end obtained by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in the presence of (C). The active conjugated diene polymer has two alkali metal terminals.

(C) is a chemical species obtained by reacting the compound represented by the above formula (1) with an organic alkali metal compound.

In the formula (1), examples of the branched or unbranched alkyl group of R ¹¹ and R ¹² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an iso-butyl group, sec -1-30 carbon atoms (preferably 1-8 carbon atoms, etc.) such as butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group, decyl group Preferred examples include alkyl groups having 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms. The alkyl group includes a group in which a hydrogen atom of the alkyl group is substituted with an aryl group (such as a phenyl group).

Examples of the branched or unbranched aryl group of R ¹¹ and R ¹² include those having 6 to 18 carbon atoms (preferably 6 to 8 carbon atoms) such as phenyl group, tolyl group, xylyl group, naphthyl group, and biphenyl group. An aryl group is mentioned. The aryl group includes a group in which a hydrogen atom of the aryl group is substituted with an alkyl group (such as a methyl group).

Examples of the branched or unbranched alkoxy group for R ¹¹ and R ¹² include 1 to 8 carbon atoms such as a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a t-butoxy group. Alkoxy groups (preferably having 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms). The alkoxy group includes a cycloalkoxy group (cycloalkoxy group having 5 to 8 carbon atoms such as cyclohexyloxy group) and an aryloxy group (aryloxy group having 6 to 8 carbon atoms such as phenoxy group and benzyloxy group). ) Is also included.

Examples of the branched or unbranched silyloxy group of R ¹¹ and R ¹² include a silyloxy group substituted with an aliphatic group having 1 to 20 carbon atoms or an aromatic group (trimethylsilyloxy group, triethylsilyloxy group, triisopropylsilyl group). Oxy group, diethyl isopropylsilyloxy group, t-butyldimethylsilyloxy group, t-butyldiphenylsilyloxy group, tribenzylsilyloxy group, triphenylsilyloxy group, tri-p-xylylsilyloxy group, etc.) Can be mentioned.

Examples of the branched or unbranched acetal group of R ¹¹ and R ¹² include groups represented by —C (RR ′) — OR ″ and —O—C (RR ′) — OR ″. . Examples of the former include a methoxymethyl group, an ethoxymethyl group, a propoxymethyl group, a butoxymethyl group, an isopropoxymethyl group, a t-butoxymethyl group, and a neopentyloxymethyl group. Methoxy group, propoxymethoxy group, i-propoxymethoxy group, n-butoxymethoxy group, t-butoxymethoxy group, n-pentyloxymethoxy group, n-hexyloxymethoxy group, cyclopentyloxymethoxy group, cyclohexyloxymethoxy group, etc. Can be mentioned.

R ¹¹ and R ¹² are preferably a hydrogen atom, a branched or unbranched alkyl group, or a branched or unbranched aryl group. This can improve the balance between low fuel consumption and wet grip performance. Moreover, because it can grow evenly polymer in two directions, it is preferable R ^11, R ¹² are identical groups.

Examples of the branched or unbranched alkylene group of A include, for example, a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, an undecylene group, and a dodecylene group. Group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group, etc., and alkylene groups having 1 to 30 carbon atoms (preferably having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms). .

Examples of the derivative of the alkylene group of A include an alkylene group substituted with an aryl group or an arylene group.

As said arylene group of A, a phenylene group, a tolylene group, a xylylene group, a naphthylene group etc. are mentioned, for example.

Examples of the arylene group derivative of A include an arylene group substituted with an alkylene group.

As A, a branched or unbranched arylene group is preferable, and a phenylene group (a compound represented by the following formula (2)) is more preferable.

^{R 11} and ^{R 12} in the formula (2) are the same as ^{R 11} and ^{R 12} in the formula (1).

Specific examples of the compound represented by the formula (1) or (2) include 1,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene, 1,2-diisopropenylbenzene, 1,3-diisopropenylbenzene, 1,4-diisopropenylbenzene, 1,2-diisobutenylbenzene, 1,3-diisobutenylbenzene, 1,4-diisobutenylbenzene, 1,3-phenylenebis (1 -Vinylbenzene), 1,4-phenylenebis (1-vinylbenzene), 1,1'-methylenebis (2-vinylbenzene), 1,1'-methylenebis (3-vinylbenzene), 1,1'-methylenebis (4-vinylbenzene) and the like. These may be used alone or in combination of two or more. Of these, 1,3-divinylbenzene, 1,3-diisopropenylbenzene, and 1,3-phenylenebis (1-vinylbenzene) are preferable.

Examples of the organic alkali metal compound used in the present invention include hydrocarbon compounds containing an alkali metal such as lithium, sodium, potassium, rubidium, and cesium. Of these, lithium or sodium compounds having 2 to 20 carbon atoms are preferred. Specific examples thereof include, for example, ethyl lithium, n-propyl lithium, iso-propyl lithium, n-butyl lithium, sec-butyl lithium, t-octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, 2 -Butyl-phenyl lithium, 4-phenyl-butyl lithium, cyclohexyl lithium, 4-cyclopentyl lithium, 1,4-dilithio-butene-2 and the like. Among these, n-butyllithium or sec-butyllithium is preferable in that the reaction proceeds rapidly to give a polymer having a narrow molecular weight distribution.

The method for preparing (C) is not particularly limited as long as it is a method in which the compound represented by the above formula (1) is brought into contact with the organic alkali metal compound. Specifically, the compound represented by the formula (1) and the organic alkali metal compound are separately dissolved in an organic solvent inert to the reaction, for example, a hydrocarbon solvent, and represented by the formula (1). (C) can be prepared by dropping the organic alkali metal compound solution into the compound solution with stirring. In addition, as for the reaction temperature at the time of preparing (C), 40-60 degreeC is preferable.

The hydrocarbon solvent does not deactivate the organic alkali metal compound (alkali metal catalyst), and the suitable hydrocarbon solvent is selected from aliphatic hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons. Propane, n-butane, iso-butane, n-pentane, iso-pentane, n-hexane, cyclohexane, propene, 1-butene, iso-butene, trans-2-butene, particularly having 2 to 12 carbon atoms, Examples thereof include cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, and ethylbenzene. Moreover, these solvents can be used in mixture of 2 or more types.

Examples of the conjugated diene monomer used in the present invention include 1,3-butadiene, isoprene, 1,3-pentadiene (piperine), 2,3-dimethyl-1,3-butadiene, 1,3-hexadiene and the like. Of these, 1,3-butadiene and isoprene are preferred from the viewpoint of the physical properties of the resulting polymer and the availability for industrial implementation.

Examples of the aromatic vinyl monomer used in the present invention include styrene, α-methylstyrene, vinyl toluene, vinyl naphthalene, divinyl benzene, trivinyl benzene, and divinyl naphthalene. Of these, styrene is preferred from the viewpoint of the physical properties of the polymer obtained and the availability for industrial implementation.

As the monomer, only a conjugated diene monomer may be used, or a conjugated diene monomer and an aromatic vinyl monomer may be used in combination. When the conjugated diene monomer and the aromatic vinyl monomer are used in combination, the ratio of both is preferably 50/50 to 90/10, more preferably 55/45 to 85/15, in terms of the conjugated diene monomer / aromatic vinyl monomer mass ratio. It is. If the ratio is less than 50/50, the polymer rubber may become insoluble in the hydrocarbon solvent, and uniform polymerization may not be possible. On the other hand, if the ratio exceeds 90/10, the strength of the polymer rubber may be reduced. May decrease.

As the modified diene polymer, one obtained by copolymerizing a conjugated diene monomer and an aromatic vinyl monomer is preferable, and one obtained by copolymerizing 1,3-butadiene and styrene (modified styrene butadiene rubber). Is particularly preferred. When such a modified copolymer is used together with silica-containing carbon black and silica, it is possible to improve the performance balance between low fuel consumption and fracture characteristics.

There is no restriction | limiting in particular as a preparation method of (A) except using (C) as a polymerization initiator, A conventionally well-known method can be used. Specifically, a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer are optionally used in a reaction inert organic solvent such as a hydrocarbon solvent, using (C) as a polymerization initiator. By polymerizing in the presence of a mizer, an active conjugated diene-based polymer having two target alkali metal ends can be obtained.

As a hydrocarbon solvent, the thing similar to the case of the preparation of said (C) can be used conveniently.

A randomizer is a microstructure control of a conjugated diene moiety in a polymer, such as an increase in 1,2-bond in butadiene, a 3,4-bond in isoprene, or a control of the composition distribution of monomer units in the polymer, for example It is a compound having an action such as randomization of butadiene units and styrene units in a butadiene-styrene copolymer.

Various compounds can be used as a randomizer. Of these, ether compounds or tertiary amines are preferred from the viewpoint of industrial availability. Examples of ether compounds include cyclic ethers such as tetrahydrofuran, tetrahydropyran, and 1,4-dioxane; aliphatic monoethers such as diethyl ether and dibutyl ether; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether, Examples thereof include aliphatic ethers such as diethylene glycol dibutyl ether; aromatic ethers such as diphenyl ether and anisole. Examples of tertiary amine compounds include triethylamine, tripropylamine, tributylamine, N, N, N ′, N′-tetramethylethylenediamine, N, N-diethylaniline, pyridine, quinoline and the like. Can give.

(B) is a modifier having a functional group. As (B), the same modifier as the above-mentioned modifier 1 can be used suitably, and the functional group which the modifier has is also preferably the same functional group as the modifier 1.

Moreover, it is preferable that (B) to be used is one type (the modifiers introduced at both ends of (A) are the same). By using only one type of (B), the same functional group can be introduced at both ends of (A), and the reactivity with silica is stabilized by forming uniform polymer ends.

The modified diene polymer is obtained by reacting (A) and (B) in an organic solvent inert to the reaction, for example, a hydrocarbon solvent.

As a hydrocarbon solvent, the thing similar to the case of the preparation of said (C) can be used conveniently.

The amount of the modifier (B) having a functional group is preferably 0.1 to 10 mol, more preferably 0.5 to 2 mol, relative to 1 mol of the organic alkali metal compound. When the amount is less than 0.1 mol, the effect of improving the fuel efficiency is small. Conversely, when the amount exceeds 10 mol, (B) remains in the polymerization solvent. This is economically undesirable because it requires a separation step.

Since the reaction between (A) and (B) occurs rapidly, the reaction temperature and reaction time can be selected in a wide range. Generally, it is room temperature (25) -80 degreeC and several seconds-several hours. The reaction may be performed by bringing (A) and (B) into contact. For example, a method of polymerizing a diene polymer using (C) and adding a predetermined amount of (B) to the polymer solution. However, it can be exemplified as a preferred embodiment, but is not limited to this method.

From the viewpoint of kneadability, _a coupling agent represented by the general formula R _a MX _b may be added before or after the reaction of (A) and (B) (wherein R is an alkyl group, an alkenyl group, A cycloalkenyl group or an aromatic hydrocarbon group, M represents a silicon or tin atom, X represents a halogen atom, a represents an integer of 0 to 2, and b represents an integer of 2 to 4. The amount of the coupling agent is preferably 0.03 to 0.4 mol, more preferably 0.05 to 0.3 mol, per mol of the organic alkali metal compound (alkali metal catalyst) used. When the amount used is less than 0.03, the effect of improving the workability is small. Conversely, when the amount exceeds 0.4 mol, the alkali metal terminal reacting with the modifier having a functional group is reduced, and the fuel efficiency is improved. The effect is reduced.

After completion of the reaction, the modified diene polymer can be coagulated by a coagulation method used in the production of rubber by ordinary solution polymerization such as addition of a coagulant or steam coagulation, and can be separated from the reaction solvent. The solidification temperature is not limited at all.

A modified diene polymer is obtained by drying the coagulated product separated from the reaction solvent. For drying the coagulated product, a band drier, an extrusion drier, etc. used in normal synthetic rubber production can be used, and the drying temperature is not limited at all.

The vinyl content of the conjugated diene part of the modified diene rubber is not particularly limited, but is preferably 10 to 70 mol%, more preferably 15 to 60 mol%. The lower limit is more preferably 35 mol% or more, and particularly preferably 40 mol% or more. When it is less than 10 mol%, the glass transition temperature of the polymer becomes low, and when used as a polymer for tires, grip performance (wet grip performance) tends to be inferior, whereas when it exceeds 70 mol%, The glass transition temperature of the polymer rises and tends to be inferior in rebound resilience.
The vinyl content (1,2-bond butadiene unit amount) can be measured by the method described in the examples.

The styrene content of the modified diene rubber is not particularly limited, but is preferably 5 to 35 mol%, more preferably 8 to 25 mol%, still more preferably 8 to 15 mol%. If it is less than 5 mol%, the wet grip performance tends to be inferior. On the other hand, if it exceeds 35 mol%, the fuel economy may be deteriorated.
The styrene content can be measured by the method described in the examples.

The weight average molecular weight of the modified diene rubber is not particularly limited, but is preferably 100,000 to 2,000,000, more preferably 150,000 to 1500,000. If it is less than 100,000, the fuel efficiency tends to be inferior. On the other hand, if it exceeds 2000000, the processability tends to deteriorate.
In addition, a weight average molecular weight can be measured by the method as described in an Example.

The content of the modified diene rubber in 100% by mass of the rubber component is 10% by mass or more, preferably 30% by mass or more, more preferably 50% by mass or more, and further preferably 70% by mass or more. If it is less than 10% by mass, sufficient fuel economy and destructive properties may not be obtained. The content of the diene polymer may be 100% by mass, but is preferably 90% by mass or less.

As another rubber component, the above-mentioned diene polymer is mentioned, for example. Of these, NR and BR are preferable. These may be used alone or in combination of two or more.

The NR is not particularly limited, and for example, those commonly used in the tire industry such as SIR20, RSS # 3, TSR20 and the like can be used.

When NR is blended in the rubber composition of the present invention, the content of NR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more. If it is less than 5% by mass, the fracture strength and low heat build-up tend to be inferior. The NR content is preferably 40% by mass or less, more preferably 30% by mass or less. If it exceeds 40% by mass, fuel economy and grip performance (wet grip performance) may be deteriorated.

The BR is not particularly limited. For example, BR1220 manufactured by Nippon Zeon Co., Ltd., BR150B manufactured by Ube Industries, Ltd., high cis content BR, etc. Commonly used in the tire industry such as BR containing 2-syndiotactic polybutadiene crystal (SPB) can be used. Among these, BR having a cis content of 95% by mass or more is preferable.

When BR is blended in the rubber composition of the present invention, the content of BR in 100% by mass of the rubber component is preferably 15% by mass or more, more preferably 30% by mass or more. If it is less than 15% by mass, the fracture strength and low heat build-up tend to be inferior. The BR content is preferably 65% by mass or less, more preferably 50% by mass or less. If it exceeds 65% by mass, fuel economy and grip performance (wet grip performance) may be deteriorated.

In the rubber composition of the present invention, silica-containing carbon black, silica, and, if necessary, carbon black are used as fillers. By using silica-containing carbon black together with silica, the dispersibility of silica, which was difficult with silica alone, is improved. Therefore, the performance of silica is exhibited to the maximum, and both low exothermic properties and fracture characteristics can be achieved.

Silica-containing carbon black (carbon black containing silica) is such that carbon black and silica are three-dimensionally mixed in one particle, and both silica and carbon black are exposed on the particle surface. Yes, for example, those described in JP-A-2001-167051.

In the silica-containing carbon black, both the carbon black part and the silica part have a part exposed on the surface of the particle, so the effect obtained by using the carbon black, for example, excellent fracture characteristics under severe conditions can get. Further, since silica is also contained, it becomes easy to bond to the polymer via the binder, and hysteresis can be reduced.

The silica content in 100% by mass of silica-containing carbon black is preferably from 0.1 to 70% by mass, preferably from 0.2 to 50% by mass, more preferably from the viewpoint of the balance between low fuel consumption and performance of fracture characteristics. It is 0.5-25 mass%, More preferably, it is 2-10 mass%. The silica-containing carbon black preferably has the same range of silica content on the surface. The content of silica present on the surface can be measured from a photograph taken with an electron microscope.

The method for producing the silica-containing carbon black is not particularly limited, but a method in which an organic siloxane is reacted simultaneously with the raw material oil and produced in one step is preferable. The preferred production method is disclosed in detail in, for example, WO 96/37547.

The content of the silica-containing carbon black is preferably 1 part by mass or more, more preferably 7 parts by mass or more, and still more preferably 10 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 1 part by mass, the effect of blending may not be sufficiently obtained. Further, the content of the silica-containing carbon black is preferably 50 parts by mass or less, more preferably 35 parts by mass or less, and still more preferably 30 parts by mass or less. When it exceeds 50 mass parts, workability will fall and there exists a tendency for low-fuel-consumption property and destruction characteristics to deteriorate.

The silica is not particularly limited, and examples thereof include dry process silica (anhydrous silicic acid), wet process silica (hydrous silicic acid), and the like, but wet process silica is preferable because of its large number of silanol groups.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 100 m ² / g or more, more preferably 150 m ² / g or more. If it is less than 100 m ² / g, the reinforcing effect is small, and the fracture characteristics tend to deteriorate. Further, N ₂ SA of silica is preferably 220 m ² / g or less, more preferably 200 m ² / g or less. When it exceeds 220 m ² / g, the dispersibility of silica is lowered, and there is a possibility that sufficient fuel economy, fracture characteristics and wet grip performance may not be obtained.
The nitrogen adsorption specific surface area of silica is a value measured by the BET method according to ASTM D3037-81.

The content of silica is preferably 15 parts by mass or more, more preferably 25 parts by mass or more with respect to 100 parts by mass of the rubber component. When the amount is less than 15 parts by mass, the fuel efficiency tends to decrease. The silica content is preferably 90 parts by mass or less, more preferably 70 parts by mass or less, and still more preferably 55 parts by mass or less. When it exceeds 90 mass parts, workability will fall and performance, such as a fracture characteristic, tends to deteriorate.

The carbon black is not particularly limited, and for example, GPF, HAF, ISAF, SAF and the like can be used.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 30 m ² / g or more, more preferably 50 m ² / g or more, and still more preferably 60 m ² / g or more. When N ₂ SA is less than 30 m ² / g, there is a tendency that sufficient reinforcing properties cannot be obtained. Also, _N 2 SA is preferably 150 meters ² / g or less of carbon black, more preferably not more than ^{100m 2 / g, 80m 2 /} g or less is more preferable. When N ₂ SA exceeds 150 m ² / g, fuel economy tends to deteriorate.
In addition, the nitrogen adsorption specific surface area of carbon black is measured according to JIS K6217-2: 2001.

Carbon black has a dibutyl phthalate (DBP) oil absorption of preferably 90 ml / 100 g or more, more preferably 110 ml / 100 g or more, and even more preferably 120 ml / 100 g or more. The DBP oil absorption of carbon black is preferably 160 ml / 100 g or less, more preferably 140 ml / 100 g or less. By making it within this range, fuel economy and destruction characteristics can be improved in a well-balanced manner.
The DBP oil absorption of carbon black is measured according to JIS K6217-4: 2001.

When carbon black is blended, the content thereof is preferably 2 parts by mass or more, more preferably 4 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 2 parts by mass, the reinforcing effect may not be sufficiently obtained. The carbon black content is preferably 30 parts by mass or less, more preferably 15 parts by mass or less. If it exceeds 30 parts by mass, the fuel efficiency tends to deteriorate.

The total content of silica-containing carbon black, silica and carbon black is preferably 20 parts by mass or more, and more preferably 40 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 20 parts by mass, the reinforcing effect may not be sufficiently obtained. The total content is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, and still more preferably 70 parts by mass or less. If it exceeds 100 parts by mass, the processability tends to deteriorate, and the fuel economy and fracture characteristics tend to deteriorate.

In the present invention, it is preferable to use a silane coupling agent together with silica. Examples of the silane coupling agent include sulfide, mercapto, vinyl, amino, glycidoxy, nitro, and chloro silane coupling agents. Specifically, a compound represented by the following formula (3) or (4), a silane coupling agent having a mercapto group, and the like can be used. Mercapto-based silane coupling agents are preferred from the standpoint of significantly improving the properties and fracture characteristics.

In formulas (3) and (4), R ^{11 to} R ¹³ represent a branched or unbranched alkyl group, or a branched or unbranched alkoxy group. When R ^{11 to} R ¹³ are branched or unbranched alkyl groups, the carbon number is 1 to 12, and preferably 1 to 10. When R ^{11 to} R ¹³ are branched or unbranched alkoxy groups, the carbon number is 1 to 12, preferably 1 to 6, and more preferably 1 to 3. When the number of carbon atoms in R ^{11 to} R ¹³ exceeds 12, the reactivity with silica tends to decrease.

R ¹⁴ represents a branched or unbranched alkylene group. The number of carbon atoms in R ¹⁴ is 1-6. R ¹⁵ represents a branched or unbranched alkyl group. The number of carbon atoms of R ¹⁵ is 1 to 30.

X represents the number of sulfur atoms in the polysulfide part. The average value of X (average number of sulfur chains) is 2 to 8, preferably 2 to 4. If the average value of X is less than 2, the reactivity with the rubber component tends to be low, and if it exceeds 8, rubber burns tend to occur during processing.

Z represents R ¹¹ R ¹² R ¹³ —Si—R ¹⁴ —, a branched or unbranched alkyl group, a branched or unbranched acyl group, or a branched or unbranched aryl group. When Z is a branched or unbranched alkyl group, it has 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms. When Z is a branched or unbranched acyl group, the carbon number is 2 to 12, preferably 2 to 6. When Z is a branched or unbranched aryl group, the carbon number is 6 to 12, preferably 6 to 10.

（式（５）中、Ｒ^１０１〜Ｒ^１０３は、分岐若しくは非分岐の炭素数１〜１２のアルキル基、分岐若しくは非分岐の炭素数１〜１２のアルコキシ基、又は−Ｏ−（Ｒ^１１１−Ｏ）_ｚ−Ｒ^１１２（ｚ個のＲ^１１１は、分岐若しくは非分岐の炭素数１〜３０の２価の炭化水素基を表す。ｚ個のＲ^１１１はそれぞれ同一でも異なっていてもよい。Ｒ^１１２は、分岐若しくは非分岐の炭素数１〜３０のアルキル基、分岐若しくは非分岐の炭素数２〜３０のアルケニル基、炭素数６〜３０のアリール基、又は炭素数７〜３０のアラルキル基を表す。ｚは１〜３０の整数を表す。）で表される基を表す。Ｒ^１０１〜Ｒ^１０３はそれぞれ同一でも異なっていてもよい。Ｒ^１０４は、分岐若しくは非分岐の炭素数１〜６のアルキレン基を表す。）

（式（６）及び（７）中、Ｒ^２０１は水素、ハロゲン、分岐若しくは非分岐の炭素数１〜３０のアルキル基、分岐若しくは非分岐の炭素数２〜３０のアルケニル基、分岐若しくは非分岐の炭素数２〜３０のアルキニル基、又は該アルキル基の末端の水素が水酸基若しくはカルボキシル基で置換されたものを表す。Ｒ^２０２は分岐若しくは非分岐の炭素数１〜３０のアルキレン基、分岐若しくは非分岐の炭素数２〜３０のアルケニレン基、又は分岐若しくは非分岐の炭素数２〜３０のアルキニレン基を表す。Ｒ^２０１とＲ^２０２とで環構造を形成してもよい。） As a silane coupling agent having a mercapto group (mercapto silane coupling agent), a compound represented by the following formula (5) and / or a binding unit A represented by the following formula (6) and the following formula (7 The compound containing the coupling | bonding unit B shown by can be used suitably.

(In the formula (5), R ^{101 to} R ¹⁰³ are each a branched or unbranched C 1-12 alkyl group, a branched or unbranched C 1-12 alkoxy group, or —O— (R ¹¹¹ — O) _z- R ¹¹² (z R ¹¹¹ represents a branched or unbranched divalent hydrocarbon group having 1 to 30 carbon atoms. The z R ^{111 s} may be the same as or different from each other. ¹¹² represents a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms. Z represents an integer of 1 to 30.) R ^{101 to} R ¹⁰³ may be the same as or different from each other, and R ¹⁰⁴ has 1 to 6 carbon atoms which are branched or unbranched. Represents an alkylene group of

(In the formulas (6) and (7), R ²⁰¹ is hydrogen, halogen, branched or unbranched alkyl group having 1 to 30 carbon atoms, branched or unbranched alkenyl group having 2 to 30 carbon atoms, branched or unbranched. Or an alkyl group substituted with a hydroxyl group or a carboxyl group, and R ²⁰² represents a branched or unbranched C 1-30 alkylene group, branched or It represents an unbranched C2-C30 alkenylene group or a branched or unbranched C2-C30 alkynylene group, and R ²⁰¹ and R ²⁰² may form a ring structure.)

Hereinafter, the compound represented by Formula (5) is demonstrated.
By using the compound represented by Formula (5), a filler can disperse | distribute favorably and low fuel consumption and a fracture characteristic can be improved notably.

R ^{101 to} R ¹⁰³ are each a branched or unbranched alkyl group having 1 to 12 carbon atoms, a branched or unbranched alkoxy group having 1 to 12 carbon atoms, or —O— (R ¹¹¹ —O) _z —R ¹¹² . Represents the group represented. Among these, at least one of R ^{101 to} R ¹⁰³ is preferably a group represented by —O— (R ¹¹¹ —O) _z —R ¹¹² , and two of them are —O— (R ¹¹¹ —O) _z —. a group represented by R ^112, and it is more preferred one is a branched or unbranched alkoxy group having 1 to 12 carbon atoms.

Examples of the branched or unbranched alkyl group having 1 to 12 carbon atoms (preferably 1 to 5 carbon atoms) represented by R ^{101 to} R ¹⁰³ include, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and n-butyl. Group, iso-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group and the like.

Examples of the branched or unbranched alkoxy group having 1 to 12 carbon atoms (preferably 1 to 5 carbon atoms) of R ^{101 to} R ¹⁰³ include, for example, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, n- Examples include butoxy, iso-butoxy, sec-butoxy, tert-butoxy, pentyloxy, hexyloxy, heptyloxy, 2-ethylhexyloxy, octyloxy, nonyloxy and the like.

In —O— (R ¹¹¹ —O) _z —R ¹¹² of R ^{101 to} R ¹⁰³ , R ¹¹¹ represents a branched or unbranched carbon number of 1 to 30 (preferably having 1 to 15 carbon atoms, more preferably 1 carbon number). To 3) a divalent hydrocarbon group. Examples of the hydrocarbon group include a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched alkenylene group having 2 to 30 carbon atoms, and a branched or unbranched alkynylene group having 2 to 30 carbon atoms. And an arylene group having 6 to 30 carbon atoms. Of these, a branched or unbranched alkylene group having 1 to 30 carbon atoms is preferable.

Examples of the branched or unbranched alkylene group having 1 to 30 carbon atoms (preferably 1 to 15 carbon atoms, more preferably 1 to 3 carbon atoms) of R ¹¹¹ include, for example, a methylene group, an ethylene group, a propylene group, and a butylene group. Pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group and the like.

Examples of the branched or unbranched carbon atoms 2-30 alkenylene group (preferably 2 to 15 carbon atoms, more preferably 2 to 3 carbon atoms) of R ^111, for example, vinylene group, propenylene group, 2-propenylene Group, 1-butenylene group, 2-butenylene group, 1-pentenylene group, 2-pentenylene group, 1-hexenylene group, 2-hexenylene group, 1-octenylene group and the like.

Examples of the branched or unbranched carbon atoms 2-30 alkynylene group (preferably 2 to 15 carbon atoms, more preferably 2 to 3 carbon atoms) of R ^111, for example, ethynylene group, propynylene group, butynylene group, pentynylene group Hexynylene group, heptynylene group, octynylene group, noninylene group, decynylene group, undecynylene group, dodecynylene group and the like.

Examples of the arylene group having 6 to 30 carbon atoms (preferably 6 to 15 carbon atoms) of R ¹¹¹ include a phenylene group, a tolylene group, a xylylene group, and a naphthylene group.

z represents an integer of 1 to 30 (preferably 2 to 20, more preferably 3 to 7, further preferably 5 to 6).

R ¹¹² represents a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms. Represent. Of these, a branched or unbranched alkyl group having 1 to 30 carbon atoms is preferable.

Examples of the branched or unbranched alkyl group having 1 to 30 carbon atoms (preferably 3 to 25 carbon atoms, more preferably 10 to 15 carbon atoms) of R ¹¹² include, for example, a methyl group, an ethyl group, an n-propyl group, Isopropyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl , Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, octadecyl group and the like.

Examples of the branched or unbranched alkenyl group having 2 to 30 carbon atoms (preferably 3 to 25 carbon atoms, more preferably 10 to 15 carbon atoms) for R ¹¹² include, for example, a vinyl group, a 1-propenyl group, and 2-propenyl. Group, 1-butenyl group, 2-butenyl group, 1-pentenyl group, 2-pentenyl group, 1-hexenyl group, 2-hexenyl group, 1-octenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group Group, pentadecenyl group, octadecenyl group and the like.

Examples of the aryl group having 6 to 30 carbon atoms (preferably 10 to 20 carbon atoms) of R ¹¹² include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a biphenyl group.

Examples of the aralkyl group having 7 to 30 carbon atoms (preferably 10 to 20 carbon atoms) of R ¹¹² include a benzyl group and a phenethyl group.

Specific examples of the group represented by —O— (R ¹¹¹ —O) _z —R ¹¹² include, for example, —O— (C ₂ H ₄ —O) ₅ —C ₁₁ H ₂₃ , —O— (C _{2 H 4 -O) 5 -C 12 H} 25, -O- (C 2 H 4 -O) 5 -C 13 H 27, -O- (C 2 H 4 -O) 5 -C 14 H 29, -O _{- (C 2 H 4 -O)} 5 -C 15 H 31, -O- (C 2 H 4 -O) 3 -C 13 H 27, -O- (C 2 H 4 -O) 4 -C 13 H _{27, -O- (C 2 H 4} -O) 6 -C 13 H 27, such as _{-O- (C 2 H 4 -O)} 7 -C 13 H 27 and the like. Among _{these, -O- (C 2 H 4 -O} ) 5 -C 11 H 23, -O- (C 2 H 4 -O) 5 -C 13 H 27, -O- (C 2 H 4 -O) 5 _{-C 15 H 31, -O- (C} 2 H 4 -O) 6 -C 13 H 27 are preferable.

Examples of the branched or unbranched alkylene group having 1 to 6 carbon atoms (preferably 1 to 5 carbon atoms) of R ¹⁰⁴ include the same groups as the branched or unbranched alkylene group having 1 to 30 carbon atoms of R ^111. Can give.

Examples of the compound represented by the above formula (5) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the following formula: The compound represented by the following formula (Si363 manufactured by EVONIK-DEGUSSA) and the like can be used, and a compound represented by the following formula can be preferably used. These may be used alone or in combination of two or more.

Next, the compound containing the bond unit A represented by the formula (6) and the bond unit B represented by the formula (7) will be described.

The compound containing the bond unit A represented by the formula (6) and the bond unit B represented by the formula (7) is more viscous during processing than a polysulfide silane such as bis- (3-triethoxysilylpropyl) tetrasulfide. The rise is suppressed. This is presumably because the increase in Mooney viscosity is small because the sulfide portion of the bond unit A is a C—S—C bond and is thermally stable compared to tetrasulfide and disulfide.

Moreover, the shortening of the scorch time is suppressed as compared with mercaptosilane such as 3-mercaptopropyltrimethoxysilane. This is because the bonding unit B has a structure of mercaptosilane, but the —C ₇ H ₁₅ part of the bonding unit A covers the —SH group of the bonding unit B, so that it does not easily react with the polymer and scorch is less likely to occur. This is probably because of this.

In the silane coupling agent having the above structure, the content of the bond unit A is preferably 30 from the viewpoint that the effect of suppressing the increase in viscosity during processing and the effect of suppressing the shortening of the scorch time can be enhanced. It is at least mol%, more preferably at least 50 mol%, preferably at most 99 mol%, more preferably at most 90 mol%. The content of the binding unit B is preferably 1 mol% or more, more preferably 5 mol% or more, further preferably 10 mol% or more, and preferably 70 mol% or less, more preferably 65 mol% or less, More preferably, it is 55 mol% or less. Further, the total content of the binding units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%.
The content of the bond units A and B is an amount including the case where the bond units A and B are located at the terminal of the silane coupling agent. The form in which the bonding units A and B are located at the end of the silane coupling agent is not particularly limited, as long as the units corresponding to the formulas (6) and (7) indicating the bonding units A and B are formed. .

Examples of the halogen for R ²⁰¹ include chlorine, bromine, and fluorine.

^Examples of the branched or unbranched alkyl group having 1 to 30 carbon atoms of R ²⁰¹ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, iso-butyl group, sec-butyl group, tert- Examples thereof include a butyl group, a pentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group, an octyl group, a nonyl group, and a decyl group. The number of carbon atoms of the alkyl group is preferably 1-12.

^Examples of the branched or unbranched C 2-30 alkenyl group of R ²⁰¹ include a vinyl group, 1-propenyl group, 2-propenyl group, 1-butenyl group, 2-butenyl group, 1-pentenyl group, and 2-pentenyl. Group, 1-hexenyl group, 2-hexenyl group, 1-octenyl group and the like. The alkenyl group preferably has 2 to 12 carbon atoms.

^Examples of the branched or unbranched alkynyl group having 2 to 30 carbon atoms of R ²⁰¹ include ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, heptynyl group, octynyl group, nonynyl group, decynyl group, undecynyl group, And dodecynyl group. The alkynyl group preferably has 2 to 12 carbon atoms.

Examples of the branched or unbranched alkylene group having 1 to 30 carbon atoms of R ²⁰² include an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, an undecylene group, Examples include dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group and the like. The alkylene group preferably has 1 to 12 carbon atoms.

^Examples of the branched or unbranched C2-C30 alkenylene group of R202 include vinylene group, 1-propenylene group, 2-propenylene group, 1-butenylene group, 2-butenylene group, 1-pentenylene group and 2-pentenylene. Group, 1-hexenylene group, 2-hexenylene group, 1-octenylene group and the like. The alkenylene group preferably has 2 to 12 carbon atoms.

Examples of branched or unbranched alkynylene group having 2 to 30 carbon atoms R ^202, ethynylene group, propynylene group, butynylene group, pentynylene group, hexynylene group, heptynylene group, octynylene group, nonynylene group, decynylene group, undecynylene group, And dodecynylene group. The alkynylene group preferably has 2 to 12 carbon atoms.

In the compound containing the bond unit A represented by the formula (6) and the bond unit B represented by the formula (7), the total number of repetitions of the bond unit A repeat number (x) and the bond unit B repeat number (y) The number (x + y) is preferably in the range of 3 to 300. Within this range, since the mercaptosilane of the bond unit B is covered by —C ₇ H ₁₅ of the bond unit A, it is possible to suppress the scorch time from being shortened and to have good reactivity with silica and rubber components. Can be secured.

For example, NXT-Z30, NXT-Z45, or NXT-Z60 manufactured by Momentive is used as the compound containing the binding unit A represented by the formula (6) and the coupling unit B represented by the formula (7). Can do. These may be used alone or in combination of two or more.

The content of the silane coupling agent having a mercapto group is preferably 2 parts by mass or more and more preferably 4 parts by mass or more with respect to 100 parts by mass of the total amount of silica and silica-containing carbon black. If it is less than 2 parts by mass, the fracture characteristics tend to be lowered. The content is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less. When the amount exceeds 15 parts by mass, effects such as improvement of fracture characteristics and reduction of rolling resistance due to the addition of the silane coupling agent tend to be insufficient.
In the present invention, even when another silane coupling agent such as sulfide is used, the total content of the silane coupling agent to be blended is preferably within the above range.

In addition to the above components, the rubber composition of the present invention includes compounding agents generally used in the production of rubber compositions, such as reinforcing fillers such as clay, zinc oxide, stearic acid, various anti-aging agents, aromas Oils such as oils, waxes, vulcanizing agents such as sulfur, vulcanization accelerators, and the like can be appropriately blended.

As a method for producing the rubber composition of the present invention, a known method can be used. For example, the above components are kneaded using a rubber kneader such as an open roll or a Banbury mixer, and then vulcanized. Can be manufactured.

The rubber composition of the present invention can be suitably used for a base tread. The base tread is an inner layer portion of a tread having a multilayer structure. For example, a tread having a two-layer structure (a surface layer (cap tread) and an inner surface layer (base tread)) is an inner surface layer.

The pneumatic tire of the present invention is produced by a usual method using the rubber composition. That is, a rubber composition blended with various additives as necessary is extruded according to the shape of the base tread of the tire at an unvulcanized stage, and molded by a normal method on a tire molding machine, After bonding together with other tire members to form an unvulcanized tire, the tire can be manufactured by heating and pressing in a vulcanizer.

The tire of the present invention is suitably used as a passenger car tire, bus tire, truck tire, and the like.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

Hereinafter, various chemicals used in the production examples will be described together. In addition, the chemical | medical agent refine | purified according to the usual method as needed.
Cyclohexane: Tokyo Chemical Industry Co., Ltd. Tetrahydrofuran: Kanto Chemical Co., Ltd. Styrene: Kanto Chemical Co., Ltd. 1,3-Butadiene: Tokyo Chemical Industry Co., Ltd. 1,3-Divinylbenzene Hexane Solution (1. 6M): Tokyo Chemical Industry Co., Ltd. n-butyllithium hexane solution (1.6M): Kanto Chemical Co., Ltd. n-butyllithium: Kanto Chemical Co., Ltd. Methanol: Kanto Chemical Co., Ltd. 2, 6-di-tert-butyl-p-cresol: Nocrack 200 manufactured by Ouchi Shinsei Chemical Co., Ltd.
3- (N, N-dimethylaminopropyl) trimethoxysilane: manufactured by AMAX Co., Ltd. dimethylaminopropyl bromide: manufactured by Kanto Chemical Co., Inc.

(Production Example 1 Preparation of polymerization initiator)
To a 1000 ml pressure vessel fully purged with nitrogen, 100 ml of hexane solution of 1,3-divinylbenzene (1.6 M) was added, and 200 ml of hexane solution of n-butyllithium (1.6 M) was added dropwise at 0 ° C., The polymerization initiator solution was obtained by stirring for 1 hour.

(Production Example 2 Synthesis of Both-End Modified SBR (1))
An autoclave reactor with an internal volume of 5 liters purged with nitrogen was charged with 2500 g of cyclohexane, 25 g of tetrahydrofuran, 100 g of styrene, and 390 g of 1,3-butadiene. After adjusting the temperature of the reactor contents to 10 ° C., 15 ml of the polymerization initiator solution obtained in Production Example 1 was added to initiate polymerization. The polymerization was carried out under adiabatic conditions and the maximum temperature reached 85 ° C.
When the polymerization conversion rate reached 99%, 10 g of 1,3-butadiene was added, and after further polymerizing for 5 minutes, 1570 mg of 3- (N, N-dimethylaminopropyl) trimethoxysilane was added for 15 minutes. Reaction was performed. 2,6-Di-tert-butyl-p-cresol was added to the polymer solution after the reaction. Subsequently, the solvent was removed by steam stripping to obtain a both-end modified SBR (1).

(Production Example 3 Synthesis of Both-End Modified SBR (2))
Both ends modified SBR (2) was obtained in the same manner as in Production Example 2 except that 1680 mg of dimethylaminopropyl bromide was added instead of 1570 mg of 3- (N, N-dimethylaminopropyl) trimethoxysilane.

The following evaluation was performed about each obtained polymer.

(Vinyl content of conjugated diene part)
The vinyl content of the conjugated diene part of each polymer was measured by 270 MHz ¹ H-NMR.

(Styrene content)
The styrene content of each polymer was measured by 270 MHz ¹ H-NMR.

(Weight average molecular weight)
The weight average molecular weight (Mw) of each polymer is gel permeation chromatograph (GPC) (GPC-8000 series, manufactured by Tosoh Corporation), detector: differential refractometer, column: TSKGEL SUPERMALTPORE HZ-M manufactured by Tosoh Corporation. ) Based on standard polystyrene conversion.

Hereinafter, various chemicals used in Examples and Comparative Examples will be described together.
NR: RSS # 3
Both-end modified SBR (1): Production Example 2 (vinyl content of conjugated diene part: 56 mol%, bound styrene content: 20 mass%, weight average molecular weight: 300,000)
Both-end modified SBR (2): Production Example 3 (vinyl content of conjugated diene part: 54 mol%, bound styrene content: 20 mass%, weight average molecular weight: 280,000)
BR: BR130B manufactured by Ube Industries, Ltd.
Silica: Ultrasil VN3 manufactured by Degussa (N ₂ SA: 175 m ² / g)
Silica-containing carbon black: CRX2000 (N234 carbon black + silica, silica content: 4.7% by mass, silica content on the surface: 4.7% by mass) manufactured by Cabot Japan
Carbon black: N351 made by Cabot Japan (N ₂ SA: 69 m ² / g, DBP oil absorption: 128 ml / 100 g)
Silane coupling agent 1: NXT-Z45 manufactured by Momentive (copolymer of bonding unit A and bonding unit B (bonding unit A: 55 mol%, bonding unit B: 45 mol%))
Silane coupling agent 2: Si363 manufactured by Evonik Degussa
Aroma oil: Diana Process AH-24 manufactured by Idemitsu Kosan Co., Ltd.
Wax: Sunnock N manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Anti-aging agent: Antigen 6C manufactured by Sumitomo Chemical Co., Ltd.
Stearic acid: NOF made by NOF Corporation
Zinc oxide: Sulfur manufactured by Mitsui Mining & Smelting Co., Ltd .: Powder sulfur vulcanization accelerator NS manufactured by Karuizawa Sulfur Co., Ltd. NS: Noxeller NS manufactured by Ouchi Shinsei Chemical Co., Ltd.

(Examples and Comparative Examples)
In accordance with the formulation shown in Table 1 (the numbers in the table are parts by mass), using a 1.7 L Banbury mixer, kneading chemicals other than sulfur and a vulcanization accelerator for 5 minutes at 140 ° C. A kneaded paste was obtained. Furthermore, using an open roll, sulfur and a vulcanization accelerator were added to the kneaded product, and kneaded for 2 minutes at 70 ° C. to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was press vulcanized with a 0.5 mm thick mold at 170 ° C. for 20 minutes to obtain a vulcanized rubber composition.

The obtained vulcanized rubber composition was evaluated as follows, and the results are shown in Table 1. FIG. 1 shows a summary of the evaluation results.

(Destructive property test)
The prepared vulcanized rubber composition was subjected to a tensile test using a No. 3 dumbbell according to JIS-K6251, and the breaking strength (TB) and elongation at break (EB) were measured. Further, TB × EB / 2 (breaking energy) was calculated using the obtained measurement results.

(Rolling resistance index)
Using a viscoelastic spectrometer VES (manufactured by (Chichi) Iwamoto Seisakusho), the tan δ of each formulation was measured under the conditions of a temperature of 70 ° C., an initial strain of 10%, and a dynamic strain of 2%. The index was displayed. The larger the index, the better the rolling resistance.

From FIG. 1 and Table 1, an example in which three types of silica-containing carbon black, silica, and carbon black as fillers and a mercapto silane coupling agent as a silane coupling agent were blended with NR, BR, and both-end-modified SBR. Then, it became clear that the performance balance of fracture characteristics and rolling resistance was improved as compared with comparative examples such as silica and carbon black alone.

Claims (6)

1 to 50 parts by mass of silica-containing carbon black, 15 to 90 parts by mass of silica, and 0 to 30 parts by mass of carbon black with respect to 100 parts by mass of a rubber component containing a modified diene rubber having an interaction with silica A rubber composition for tires that is blended and the total content of the silica-containing carbon black, the silica, and the carbon black is 20 to 100 parts by mass. The rubber composition for a tire according to claim 1, wherein the rubber component further contains natural rubber and butadiene rubber. The rubber composition for tires according to claim 1 or 2, wherein the silica content in 100% by mass of the silica-containing carbon black is 0.1 to 70% by mass. Furthermore, the rubber composition for tires in any one of Claims 1-3 containing the silane coupling agent which has a mercapto group. It is a rubber composition for base treads, The rubber composition for tires in any one of Claims 1-4. The pneumatic tire which has a base tread produced using the rubber composition in any one of Claims 1-5.

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