Rubber composition, method for producing same, and tire
Objects of the present invention are to provide a rubber composition that can obtain a rubber elastic body having small rolling resistance and excellent impact resilience and a method for producing the same, and to provide a tire having small rolling resistance and excellent impact resilience. The rubber composition of the present invention is obtained by kneading a rubber component containing 30 to 95% by mass of a conjugated diene polymer (A) and 5 to 70% by mass of cross-linked rubber particles (B) with 20 to 100 parts by mass of silica (C) based on 100 parts by mass of the rubber component.
1. A rubber composition, comprising:
a rubber component; and
silica,
wherein the silica is included in an amount of from 20 to 100 parts by mass based on 100 parts by mass of the rubber component, and
the rubber component comprises from 30 to 95% by mass of a conjugated diene polymer comprising a hydrocarbyloxysilyl group, and from 5 to 70% by mass of cross-linked rubber particles based on the total mass of rubber component.
2. The rubber composition of claim 1 , wherein the conjugated diene polymer further comprises at least one functional group selected from the group consisting of a primary amino group, a secondary amino group, a tertiary amino group, a thiol group, an epoxy group, a thioepoxy group, an oxetane group, and a hydrocarbylthio group.
3. The rubber composition of claim 1 , wherein the cross-linked rubber particles comprise a cross-linked rubber comprising at least one rubber polymer selected from the group consisting of isoprene rubber, butadiene rubber, styrene-butadiene copolymerized rubber, styrene-isoprene copolymerized rubber, butadiene-isoprene copolymerized rubber, styrene-butadiene-isoprene copolymerized rubber, styrene-acrylonitrile-butadiene copolymerized rubber, acrylonitrile-butadiene copolymerized rubber, ethylene-α-olefin copolymerized rubber, ethylene-α-olefin-diene copolymerized rubber, chloroprene rubber, halogenated butyl rubber, polysiloxane rubber, and a graft polymer obtained by graft polymerizing at least one of a conjugated diene compound and a styrene compound thereto.
4. The rubber composition of claim 3 , wherein the cross-linked rubber is obtained by a process comprising subjecting monomers to emulsion polymerization or suspension polymerization, and the monomers comprise a multifunctional compound for forming a cross-linked structure in an amount of from 0.5 to 5 parts by mass based on 100 parts by mass of the monomers subjected to the polymerization.
5. The rubber composition of claim 4 , wherein the cross-linked rubber has a structural unit derived from at least one compound selected from the group consisting of hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, tert-butoxydimethylsilylstyrene, and isopropoxy-dimethylsilylstyrene.
6. The rubber composition of claim 1 , wherein an average particle size of the cross-linked rubber particles is from 10 to 800 nm.
7. The rubber composition of claim 1 , wherein the rubber component further comprises at least one selected from the group consisting of natural rubber, butadiene rubber, butyl rubber, synthetic isoprene rubber, styrene-butadiene copolymerized rubber, ethylene-α-olefin copolymerized rubber, ethylene-α-olefin-diene copolymerized rubber, acrylonitrile-butadiene copolymerized rubber, chloroprene rubber, and halogenated butyl rubber.