Rubber composition suitable for automobile tires and its production

Claim 1

A rubber composition comprising a base rubber comprising at least 50% by weight of a styrene/butadiene copolymer rubber, a filler consisting essentially of carbon black, and the following components each based on 100 parts by weight of the base rubber: (A) 0.1 to 10 parts by weight of a dinitrodiamine compound represented by the following formula (I): ##STR7## wherein X is a divalent aliphatic, alicyclic or aromatic group which may contain halogen or oxygen in the group; R 1 is hydrogen or an aliphatic, alicyclic or aromatic group, provided that two nitrogen atoms linking through X may further link through R 1 when both X and R 1 are the aliphatic groups; and R 2 and R 3 independently of one another are each hydrogen or an alkyl of 1 to 12 carbon atoms, provided that R 2 and R 3 may conjointly form a ring; and (B) 0.1 to 1 part by weight of a sulfide compound selected from the group consisting of disulfide represented by the following formula (II): R.sup.4 --S--S--R.sup.4 (II) wherein R 4 is benzothiazyl or N,N-dialkylthiocarbamoyl having 1 to 6 carbon atoms in each alkyl; and a substituted phenol sulfide resin represented by the following formula (III): ##STR8## wherein R 5 is an aliphatic group of 1 to 12 carbon atoms or hydroxy, y is a numeral of 1 to 6, and n is a numeral of 1 to 20; said components (A) and (B) being added to the base rubber together with the carbon black at a high temperature ranging from about 140° to about 200° C.

Claim 20

A method for lowering a rolling resistance of an automobile tire, which comprises blending a base rubber comprising at least 50% by weight of a styrene/butadiene copolymer rubber with (A) a dinitrodiamine compound represented by the following formula (I): ##STR11## wherein X is a divalent aliphatic, alicyclic or aromatic group which may contain halogen or oxygen in the group; R 1 is hydrogen or an aliphatic, alicyclic or aromatic group, provided that two nitrogen atoms linking through X may further link through R 1 when both X and R 1 are the aliphatic groups; and R 2 and R 3 independently of one another are each hydrogen or an alkyl of 1 to 12 carbon atoms, provided that R 2 and R 3 may conjointly form a ring; and (B) a sulfide compound selected from the group consisting of disulfide represented by the following formula (II): R.sup.4 --S--S--R.sup.4 (II) wherein R 4 is benzothiazyl or N,N-dialkylthiocarbamoyl having 1 to 6 carbon atoms in each alkyl; and a substituted phenol sulfide resin represented by the following formula (III): ##STR12## wherein R 5 is an aliphatic group of 1 to 12 carbon atoms or hydroxy, y is a numeral of 1 to 6, and n is a numeral of 1 to 20; simultaneously together with a filler consisting essentially of carbon black in a kneading step of a high temperature ranging from about 140° to about 200° C.

Claim 21

A method for lowering a rolling resistance of an automobile tire, which comprises blending a base rubber comprising at least 50% by weight of a styrene/butadiene copolymer rubber with (A) a dinitrodiamine compound represented by the following formula (I): ##STR11## wherein X is a divalent aliphatic, alicyclic or aromatic group which may contain halogen or oxygen in the group; R 1 is hydrogen or an aliphatic, alicyclic or aromatic group, provided that two nitrogen atoms linking through X may further link through R 1 when both X and R 1 are the aliphatic groups; and R 2 and R 3 independently of one another are each hydrogen or an alkyl of 1 to 12 carbon atoms, provided that R 2 and R 3 may conjointly form a ring; and (B) a sulfide compound selected from the group consisting of disulfide represented by the following formula (II): R.sup.4 --S--S--R.sup.4 (II) wherein R 4 is benzothiazyl or N,N-dialkylthiocarbamoyl having 1 to 6 carbon atoms in each alkyl; and a substituted phenol sulfide resin represented by the following formula (III): ##STR12## wherein R 5 is an aliphatic group of 1 to 12 carbon atoms or hydroxy, y is a numeral of 1 to 6, and n is a numeral of 1 to 20; simultaneously together with a filler consisting essentially of carbon black in a kneading step of a high temperature ranging from about 140° to about 200° C.