Process, modified rubbers and rubber compositions

A process of preparing chemically modified uncured rubber compositions comprising mixtures of at least one elastomer and at least one reinforcing filler which comprises the steps of

• (A) preparing a first mixture comprising an elastomer, at least one reinforcing filler and at least one chemical agent capable of promoting the formation of filler-elastomer linkages;
• (B) preparing a second mixture comprising an elastomer, at least one reinforcing filler and at least one chemical agent capable of promoting the formation of filler-elastomer linkages, wherein at least one of the elastomer, filler or chemical agent in the second mixture is different from the elastomer, filler or chemical agent in the first mixture;
• and
• (C) blending the first and second mixtures to form a third mixture wherein the chemical agents in the mixtures of (A) and (B) are selected from the group consisting of
• (A) aromatic furazan oxides of the partial formula ##STR35## wherein the depicted carbon atoms are a part of a single fused armatic ring,
• (B) aromatic heterocyclic di-N-oxides of the formula ##STR36## wherein R1, R2, R3 and R4 may be hydrogen, hydrocarbyl, hydrocarbyloxy, halogen, halohydrocarbyl, hydrocarbyl sulfonyl, hydrocarbyl thio, hydrocarbyl sulfoxide, amino, cyano,
• --OH
• --CHO
• --CH(O hydocarbyl)2
• --C(O)R.sup.5
• --C(O)OR.sup.5
• --C(O)NR.sup.5 R.sup.8
• --CH.dbd.N--NH--C(O)OR.sup.5
• --CH.sub.2 OC(O)CH.sub.3
• --R.sup.6 YR.sup.5
• --C(O)NHR.sup.6 OH
• --C(NH)NRR.sup.6 OH
• --C(NH)NR.sup.9 R.sup.10, or
• --C(O)NHN(R.sup.5).sub.2
• wherein each R.sup.5 is independently hydrogen or a hydrogcarbyl group, R.sup.6 is a divalent hydrocarbyl group, R.sup.8 is hydrogen, hydrocarbyl, --R.sup.6 OR.sup.5, or --R.sup.6 COOR.sup.5 ;
• R.sup.9 is hydrogen or hydrocarbyl group;
• R.sup.10 is hydrogen or a hydrocarbyl, an amino, or a hydroxyl group;
• R.sup.9 and R.sub.10 may be hydrocarbyl groups joined together to form a ring including the nitrogen atom, and Y is O, divalent S, --NH--, --S(O)-- or --S(O)-- or --S(O).sub.2 or R.sup.5 and R.sup.6 may be joined together to form a ring including the nitrogen atom, and Y is O or divalent S, or R.sup.1 and R.sup.2 and/or R.sup.3 and R.sup.4 may be joined together to form further ring systems which may be saturated or unsaturated, and further substituted or unsubstituted,
• (C) 1-hydroxy-benzimidazole 3-oxide compounds of the formula ##STR37## wherein R is hydrogen, or a halogen, hydroxyl, lower acyl, lower hydrocarbyl, lower hydrocarbyloxy, lower hydrocarbylthio, carboxyl, cyano, amino, amide or --C(O)-- lower hydrocarbyl group, and R' is hydrogen, or a lower hydrocarbyl, lower hydrocarbyl amide, carboxamide carboxy acid, carboxy ester or aryl group,
• (D) 1,3-hihydroxy-benzimidazolinone compound of the formula ##STR38## wherein R is hydrogen, or a halogen, hydroxyl, lower hydrocarbyl, lower hydrocarbyloxy, lower hydrocarbylthio, lower hydrocarbyl nitrile, carboxyl, cyano, nitro, amino, amide or --C(O)--R'" where R'" is an aryl or a lower hydrocarbyl group;
• each R' independently is H, lower alkyl, acyl, CONR"2 or CONHR" where R" is alkyl or aryl, or
• (E) aromatic nitroso compounds selected from the group consisting of nitroso-substituted aromatic amines and phenols.