Vibration-insulating rubber composition

Abstract

A vibration-insulating rubber composition includes: a rubber component (A) that is composed of an isoprene-based rubber; a rubber component (B) that is composed of a butadiene-based rubber; carbon black that is present mainly in the rubber component (B); and silica that is present mainly in the rubber component (A). The rubber composition exhibits improved durability without suffering from deterioration of vibration-insulation characteristics.

1 . A vibration-insulating rubber composition comprising:
 a rubber component (A) comprising an isoprene-based rubber;   a rubber component (B) comprising a butadiene-based rubber;   a carbon black that is present mainly in the rubber component (B); and   a silica that is present mainly in the rubber component (A).   
     
     
         2 . The vibration-insulating rubber composition of  claim 1 , wherein at least 70 wt % of a total amount of the carbon black is present in the rubber component (B), and at least 70 wt % of a total amount of the silica is present in the rubber component (A). 
     
     
         3 . The vibration-insulating rubber composition of  claim 1 , wherein the silica is modified by a silane coupling agent. 
     
     
         4 . The vibration-insulating rubber composition of  claim 3 , wherein the silane coupling agent is a polysulfide-based silane coupling agent. 
     
     
         5 . The vibration-insulating rubber composition of  claim 1 , comprising the rubber component (A) and the rubber component (B) in a weight ratio (A)/(B) in a range of 90/10 to 30/70. 
     
     
         6 . A vibration-insulating rubber composition comprising:
 a total amount of an isoprene-based rubber and a butadiene-based rubber that equals 100 parts by weight;   5 to 60 parts by weight of a carbon black; and   5 to 60 parts by weight of a silica,   wherein at least 70% of a total amount of the carbon black is unevenly distributed in the butadiene-based rubber, and at least 70% of a total amount of the silica is unevenly distributed in the isoprene-based rubber.   
     
     
         7 . A vibration-insulating rubber composition comprising:
 a rubber component comprising an isoprene-based rubber and a butadiene-based rubber; and   a reinforcing agent component comprising a carbon black and a silica, the rubber component and the reinforcing agent component being compounded,   wherein the silica in the reinforcing agent component comprises:   a silica (A) comprising silica particles whose surface has been surface-treated by a polysulfide-based silane coupling agent; and   a silica (B) comprising silica particles whose surface has been surface-treated by a silane-based surface treatment agent.   
     
     
         8 . The vibration-insulating rubber composition of  claim 7 , wherein the silane-based surface treatment agent is an alkylsilane. 
     
     
         9 . The vibration-insulating rubber composition of  claim 7 , comprising the silica (A) and the silica (B) in a weight ratio (A)/(B) of (90/10) to (40/60). 
     
     
         10 . The vibration-insulating rubber composition of  claim 7 , wherein the silica (B) is a hydrophobically modified silica obtained by processing a surface of silica with an alkylsilane. 
     
     
         11 . The vibration-insulating rubber composition of  claim 7 , wherein the rubber component comprises the isoprene-based rubber and the butadiene-based rubber in a ratio in a range of 90/10 to 30/70. 
     
     
         12 . A vibration-insulating rubber composition comprising:
 a total amount of an isoprene-based rubber and a butadiene-based rubber that equals 100 parts by weight;   5 to 60 parts by weight of a carbon black; and   5 to 60 parts by weight of a silica,   wherein the silica comprises:   40 to 90 wt % of a silica (A) that has been surface-treated by a polysulfide-based silane coupling agent, and   10 to 60 wt % of a silica (B) that has been surface-treated by an alkylsilane.   
     
     
         13 . The vibration-insulating rubber composition of  claim 1 , wherein the isoprene-based rubber comprises natural rubber, a polyisoprene rubber, or both. 
     
     
         14 . The vibration-insulating rubber composition of  claim 1 , wherein the isoprene-based rubber comprises natural rubber having a Mooney viscosity of 10 to 200. 
     
     
         15 . The vibration-insulating rubber composition of  claim 1 , wherein the isoprene-based rubber comprises natural rubber having a Mooney viscosity of 30 to 100. 
     
     
         16 . The vibration-insulating rubber composition of  claim 1 , wherein the butadiene-based rubber comprises at least one polybutadiene rubber selected from the group consisting of: a high cis-polybutadiene rubber having cis-1,4 coupling of about 90% or more, and a high vinyl-polybutadiene rubber having 1,2-coupling of about 10% or more. 
     
     
         17 . The vibration-insulating rubber composition of  claim 16 , wherein the polybutadiene rubber has a Mooney viscosity of 10 to 100. 
     
     
         18 . The vibration-insulating rubber composition of  claim 16 , wherein the polybutadiene rubber has a Mooney viscosity of 30 to 70. 
     
     
         19 . The vibration-insulating rubber composition of  claim 1 , comprising the rubber component (A) and the rubber component (B) in a weight ratio (A)/(B) in a range of 80/20 to 40/60. 
     
     
         20 . The vibration-insulating rubber composition of  claim 1 , comprising the rubber component (A) and the rubber component (B) in a weight ratio (A)/(B) in a range of 80/20 to 50/50.