Patent ID: 6518367
Filing Date: 2003-02-11
Classification: B60C,C08K,C08L

Abstract:
A vulcanized rubber composition comprising (i) a vulcanizable rubber, (ii) a reinforcing filler, and (iii) a sulfur compound having the formula (I):â€”(SxR1)nâ€”â€ƒâ€ƒ(I) wherein R1 represents an organic group,x is an average number of 3 to 5, and n is an integer of 1 to 100, â€ƒand (iv) at least one vulcanization accelerator selected from the group consisting of a thiazole base, sulfenamide base, thiuram base, and dithio acid salt base accelerators in an amount such that a ratio (iii)/(iv) by weight of the vulcanization accelerator (iv) and the polysulfide polymer (iii) is 0.3 to 4, â€ƒwherein a ratio (VM/VD) is not more than 0.4, in which: a value VM is obtained from the degree of change before and after toluene swelling of the vulcanized rubber composition treated in a lithium aluminum hydride saturated tetrahydrofuran/toluene (ratio by volume 1/1) mixed solution using the formula (A): VM=-1VS&CenterDot;[ln&af;(1-vrM)+vrM+Î¼&CenterDot;vrM2vrM1/3-vrM/2]&it;&NewLine;&it;wherein&it;â€ƒ&it;vrM=1-Ï†XM-Ï†(A)â€ƒwherein XM is the degree of change before and after toluene swelling (volume after toluene swelling/volume before toluene swelling) after treatment in a lithium aluminum hydride saturated tetrahydrofuran/toluene (ratio by volume 1/1) mixed solution, &phgr; is the volume percentage of the reinforcing filler in the rubber composition, Vs is the molecular volume of toluene, &mgr; is the rubber.toluene interaction coefficient, and vrM is the volume percentage of rubber in the swelled rubber after treatment in a lithium aluminum hydride saturated tetrahydrofuran/toluene (ratio by volume 1/1) mixed solution) and a value VD is obtained from the degree of change before and after toluene swelling of the vulcanized rubber composition treated in a propane-2-thiol (0.4 mol/1)/piperidine (0.4 mol/1) added tetrahydrofuran/toluene (ratio by volume 1/1) mixed solution using the formula (B): VD=-1VS&CenterDot;[ln&af;(1-vrD+M)+vrD+M+Î¼&CenterDot;vrD+M2vrD+M1/3-vrD+M/2-&NewLine;&it;â€ƒ&it;ln&af;(1-vrM)+vrM+Î¼&CenterDot;vrM2vrM1/3-vrM/2]&it;&NewLine;&it;wherein&it;â€ƒ&it;vrD+M=1-Ï†XD+M-Ï†(B)â€ƒwherein XD+M is the degree of change before and after toluene swelling (volume after toluene swelling/volume before toluene swelling) after treatment in a propane-2-thiol (0.4 mol/1)/piperidine (0.4 mol/1) added tetrahydrofuran/toluene (ratio by volume 1/1) mixed solution and vrD+M is the volume percentage of rubber in the swelled rubber after treatment in a propane-2-thiol (0.4 mol/1)/piperidine (0.4 mol/1) added tetrahydrofuran/toluene (ratio by volume 1/1) mixed solution.