Compositions containing silica, a phenoplast or an aminoplast, and a silane

Abstract

Silica containing mixtures for the improvement of the adhesion of vulcanizable mixtures of natural and/or synthetic rubber to reinforcing fillers or supports of textile and/or metallic fabrics after the vulcanization are prepared that substantially consist of (A) active synthetically produced silica or silicates having a specific surface area according to the BET procedure of about 50 to 500 m.sup.2 /g and an average primary particle size of from about 5 to 100 and at least one of (B) phenolic resin or aminoplast forming components, namely on the one hand phenols and/or amines and on the other hand aldehydes or aldehyde donors, and/or at least (C) one organosilane which can be a bisalkoxysilylalkyl-oligosulfide of the formula I. z-alk-S.sub.n -Alk-Z, in which Z stands for the group ##EQU1## in which R.sub.1 is an alkyl group with 1 to 4 carbon atoms or the phenyl group and R.sub.2 is an alkoxy group with 1 to 8, preferably 1 to 4 carbon atoms, a cycloalkyl group with 5 to 8 carbon atoms or a straight or branched chain alkylmercapto group with 1 to 8 carbon atoms and wherein all the R.sub.1 and R.sub.2 groups can be the same or different. Alk is a divalent hydrocarbon group with 1 to 8 carbon atoms. It can be straight or branched chain and can be a saturated aliphatic hydrocarbon group, an unsaturated aliphatic hydrocarbon group or a cyclic hydrocarbon group. Preferably Alk has 1 to 6, most preferably 2 or 3 carbon atoms and n is a number of 2 to 6, especially 2, 3 or 4, most preferably 4. The organosilane can be a mercapto group containing silane of the formula Ii. z-alk-SH in which Z and Alk areas are defined as in formula I, or the organosilane can have the general formula Iii. z-alk-A wherein Z and Alk are as defined in formula I and A is the group A. N.tbd.C-S-, b. R-S-, c. RO-CS-S-, d. RS-CS-S-, or E. R.sub.3 S-CS-S- Where R and R.sub.3 are monovalent organic groups, including hydrocarbon groups, saturated or unsaturated, branched or straight chain, acyclic, cyclic, heterocyclic or heteroaromatic group with 1 to 15 carbon atoms and 1 to 5 heteroatoms from the group of nitrogen, oxygen and sulfur and in formula III(e) R.sub.3 can be ##EQU2## wherein R.sub.4 and R.sub.5 are the same or different and are hydrogen, alkyl of 1 to 3 carbon atoms, benzyl, cycloalkyl with 5 to 7 carbon atoms or both together with the nitrogen atom form a ring having 5 to 8 atoms with up to one further nitrogen, oxygen or sulfur atom. R preferably is hydrocarbon with 1 to 8 carbon atoms, e.g., alkyl or alkenyl or heterocyclic with up to 3 nitrogen atoms.

Dependencies are inferred from the claim text.