The invention relates to silane mixtures comprising a silane of the formula I
((R.sup.1).sub.y(R.sup.2).sub.3-ySi—R.sup.3—SH  (I)
and a silane of the formula II
(R.sup.1).sub.y(R.sup.2).sub.3-ySi—R.sup.3—(S—R.sup.4).sub.z—Si(R.sup.1).sub.y(R.sup.2).sub.3-y  (II)
where the molar ratio of silane of the formula I to silane of the formula II is 20:80-85:15. The silane mixture according to the invention can be prepared by mixing the silanes of the formula I and silanes of the formula II.

The invention relates to a copolymer of ethylene and of a 1,3-diene of formula CH.sub.2═CR—CH═CH.sub.2, which copolymer bears a silanol or alkoxysilane function, the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms. Such a copolymer improves the compromise between the content of ethylene in the polymer, its crystallinity and the stiffness of a rubber composition containing it.

The invention relates to a copolymer of ethylene and of a 1,3-diene of formula CH.sub.2═CR—CH═CH.sub.2, which copolymer bears a silanol or alkoxysilane function, the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms. Such a copolymer improves the compromise between the content of ethylene in the polymer, its crystallinity and the stiffness of a rubber composition containing it.

Provided is a rubber composition having excellent low heat generating properties. The rubber composition of the present disclosure contains a rubber component, a filler containing silica, and a silane coupling agent, where the rubber component contains a conjugated diene-based polymer modified with a modifier containing a compound represented by the formula (1), and the silane coupling agent is a compound represented by the formula (2).

##STR00001##

Provided is a rubber composition having excellent low heat generating properties. The rubber composition of the present disclosure contains a rubber component, a filler containing silica, and a silane coupling agent, where the rubber component contains a conjugated diene-based polymer modified with a modifier containing a compound represented by the formula (1), and the silane coupling agent is a compound represented by the formula (2).

##STR00001##

Provided is a rubber composition having excellent low heat generating properties. The rubber composition of the present disclosure contains a rubber component, a filler containing silica, and a silane coupling agent, where the rubber component contains a conjugated diene-based polymer modified with a modifier containing a compound represented by the formula (1), and the silane coupling agent is a compound represented by the formula (2).

##STR00001##

Disclosed is a method of preparing a rubber composition comprising the steps of (a) blending in at least one preparatory mixing step at least one natural or synthetic rubbery polymer, a silica filler, a silica coupling agent, and at least one vulcanization accelerator; and (b) subsequently blending therewith in a final mixing step a sulfur curative, wherein the average glass transition temperature of the polymer(s) is −55° C. or less.

Disclosed is a method of preparing a rubber composition comprising the steps of (a) blending in at least one preparatory mixing step at least one natural or synthetic rubbery polymer, a silica filler, a silica coupling agent, and at least one vulcanization accelerator; and (b) subsequently blending therewith in a final mixing step a sulfur curative, wherein the average glass transition temperature of the polymer(s) is −55° C. or less.

Disclosed is a method of preparing a rubber composition comprising the steps of (a) blending in at least one preparatory mixing step at least one natural or synthetic rubbery polymer, a silica filler, a silica coupling agent, and at least one vulcanization accelerator; and (b) subsequently blending therewith in a final mixing step a sulfur curative, wherein the average glass transition temperature of the polymer(s) is −55° C. or less.

The present invention provides an adhesion promoting composition, or a sulfide compound-containing polysiloxane composition, having good adhesion, capable of forming a laminate having high adhesion between a metal layer and a polysiloxane layer. The adhesion promoting composition according to the present invention is an adhesion promoting composition applied to between a metal layer and a polysiloxane layer, and comprises a sulfide compound having a certain structure and a solvent. The sulfide compound-containing polysiloxane composition according to the present invention comprises a sulfide compound having a certain structure, a polysiloxane, and a solvent.