Blocked mercaptosilane coupling agents for filled rubbers

Abstract

Disclosed herein is a blocked mercaptosilane selected from the group consisting of[[(ROC(═O))—(G)]—Y—S]—G—(SiX); and  (1)[(XSi)—G]—[Y—[S—G—SiX]]  (2)wherein each R is chosen independently from hydrogen, straight, cyclic, or branched alkyl that may or may not contain unsaturation, alkenyl groups, aryl groups, and aralkyl groups, with each R containing from 1 to 18 carbon atoms; each G is independently a monovalent or polyvalent group derived by substitution of alkyl, alkenyl, aryl, or aralkyl, wherein G can contain from 1 to 18 carbon atoms, with the proviso that G is not such that the blocked mercaptosilane would contain an α,β-unsaturated carbonyl that can undergo polymerization reactions, and if G is univalent, G can be a hydrogen atom; X is independently selected from the group consisting of —Cl, —Br, RO—, RC(═O)O—, RC═NO—, RNO—, RN—, —R, and —(OSiR)(OSiR) wherein each R is as above and at least one X is not —R; p is 0 to 5; r is 1 to 3; z is 0 to 2; q is 0 to 6; a is 0 to 7; b is 1 to 3; j is 0 to 1, but it may be 0 only if p is 1; c is 1 to 6; t is 0 to 5; s is 1 to 3; k is 1 to 2; with the provisos that (I) if A is carbon, sulfur or sulfonyl, then (i) a+b is 2 and (ii) k is 1; (II) if A is phosphorus, then a+b is 3 unless both (i) c is greater than 1 and (ii) b is 1, in which case a is c+1; and (III) if A is phosphorus, then k is 2.