Rubber composition comprising a blocked mercaptosilane coupling agent

Abstract

The invention relates to a rubber composition that is free of zinc or that contains less than 0.5 parts per hundred parts of elastomer, phr, of zinc, and that is free of guanidine derivatives or contains less than 0.5 phr of guanidine derivatives, based on at least a diene elastomer, an inorganic filler as reinforcing filler, a blocked mercaptosilane corresponding to the general formula (I): in which: -the R1 symbols, which are identical or different, each represent a monovalent hydrocarbon-based group chosen from alkyls, which are linear or branched, cycloalkyls or aryls, having from 1 to 18 carbon atoms; -the R2 symbols, which are identical or different, each represent hydrogen or a monovalent hydrocarbon-based group chosen from alkyls, which are linear or branched, cycloalkyls or aryls, having from 1 to 18 carbon atoms; -the A symbol represents hydrogen or a monovalent hydrocarbon-based group chosen from alkyls, which are linear or branched, cycloalkyls or aryls, having from 1 to 18 carbon atoms and alkoxyalkyls, which are linear or branched, having from 2 to 8 carbon atoms; -the Z symbol represents a divalent bonding group comprising from 1 to 18 carbon atoms; -a is an integer equal to 1, 2 or 3.

Description

technical field [0001] The present invention relates to diene rubber compositions reinforced with inorganic fillers, such as silica, which can be used in particular for the manufacture of tires or tire semi-finished products, such as treads. Background technique [0002] In order to couple the reinforcing inorganic filler to the diene elastomer, use is made in a known manner of means intended to provide a connection of satisfactory chemical and / or physical properties between the inorganic filler (its particle surface) and the diene elastomer. An at least bifunctional coupling agent (or binding agent). [0003] The term "coupling agent" is understood to mean, in a known manner, an agent capable of establishing a bond of satisfactory chemical and / or physical properties between the inorganic filler and the diene elastomer, such an at least bifunctional coupling The linking agent has, for example, the simplified general formula "Y-Z-X", wherein: [0004] -Y represents a functi...

AI Technical Summary

Problems solved by technology

[0015] However, it was found that the removal of zinc oxide, in particular from rubber compositions reinforced with inorganic fillers such as silica, is extremely detrimental to the processing characteristics ("processability") of the rubber composition in the green state, the scorch time The reduction is absolutely unacceptable from an industrial point of view

It should be borne in mind that during the preparation of rubber compositions in a mixer, the phenomenon of "scorch" quickly leads to premature vulcanization ("scorch"), to very high viscosities in the green state and finally to almost impossible handling and Rubber compositions for industrial processing

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