RUBBER COMPOSITION FOR A TYRE COMPRISING A HYDROXYSILANE COVERING AGENT
Rubber composition which can be used in particular for the manufacture of tyres or tyre semi-finished products, such as treads, the said composition being based on at least a diene elastomer, a reinforcing inorganic filler, a coupling agent and a hydroxysilane of formula (I): R 1 (R 2 ) n Si(OH) 3-n in which: n is equal to 0, 1 or 2; R 1 represents a hydrocarbon group having at least 4 carbon atoms; R 2 represents an alkyl having from 1 to 4 carbon atoms, the R 2 alkyls being identical or different if n is equal to 2.
1 . Rubber composition based on at least a diene elastomer, a reinforcing inorganic filler, a coupling agent and a hydroxysilane of formula (I):
R 1 (R 2 ) n Si(OH) 3-n
in which:
n is equal to 0, 1 or 2;
R 1 represents a hydrocarbon group having at least 4 carbon atoms;
R 2 represents an alkyl having from 1 to 4 carbon atoms, the R 2 alkyls being identical or different if n is equal to 2.
2 . Composition according to claim 1 , in which R 1 comprises at least 5 carbon atoms.
3 . Composition according to claim 2 , in which R 1 is an alkyl having from 5 to 36 carbon atoms.
4 . Composition according to claim 3 , in which R 1 is an alkyl having from 5 to 28 carbon atoms.
5 . Composition according to claim 4 , in which R 1 is an alkyl having from 5 to 20 carbon atoms.
6 . Composition according to claim 1 , in which R 2 represents a methyl or ethyl group.
7 . Composition according to claim 6 , in which the hydroxysilane is a hydroxysilane of formula (VI), (VII) or (VIII):
in which m is greater than 2, preferably included within a range from 3 to 35.
8 . Composition according to claim 7 , in which m is greater than 3, preferably included within a range from 4 to 27.
9 . Composition according to claim 1 , in which n is equal to 1 or 2.
10 . Composition according to claim 9 , in which n is equal to 1.
11 . Composition according to claim 1 , in which the diene elastomer is chosen from the group consisting of polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers and the mixtures of these elastomers.
12 . Composition according to claim 1 , in which the reinforcing inorganic filler comprises a silica.
13 . Composition according to claim 1 , additionally comprising carbon black.
14 . Tyre or tyre semi-finished product comprising a rubber composition according to claim 1 .
15 . Tyre tread comprising a composition according to claim 1 .
16 . Use of a rubber composition according to claim 1 for the manufacture of a tyre or of a tyre semi-finished product.
17 . Process for preparing a rubber composition according to claim 1 , the said process comprising the following stages:
incorporating in a diene elastomer, during a first “non-productive” stage, at least one reinforcing inorganic filler and one coupling agent, the combined mixture being kneaded thermomechanically until a maximum temperature of between 110° C. and 190° C. is reached;
cooling the combination to a temperature of less than 100° C.;
subsequently incorporating, during a second “productive” stage, a crosslinking (or vulcanizing) system;
kneading the combined mixture until a maximum temperature of less than 120° C. is reached,
and wherein a hydroxysilane of formula (I):
R 1 (R 2 ) n Si(OH) 3-n
in which:
n is equal to 0, 1 or 2;
R 1 represents a hydrocarbon group having at least 4 carbon atoms;
R 2 represents an alkyl having from 1 to 4 carbon atoms, the R 2 alkyls being identical or different if n is equal to 2,
is additionally incorporated during the non-productive stage and/or the productive stage.