Modified diene elastomer predominantly comprising a diene elastomer coupled by an alkoxysilane compound bearing an epoxide group and amine-functionalized at the end of the chain

#This application is a 371 national phase entry of PCT/EP2014/073236, filed 29 Oct. 2014, which claims benefit of French Patent Application No. 1360607, filed 30 Oct. 2013, the entire contents of which are incorporated herein by reference for all purposes.

#The invention relates to a modified diene elastomer comprising predominantly the diene elastomer functionalized in the middle of the chain by an alkoxysilane group, optionally hydrolysed, bearing an epoxide function and functionalized at the chain end by an amine function. The invention also relates to a process for the preparation of such a modified diene elastomer, to a composition comprising it, and to a semi-finished article and a tire comprising this composition.

#Now that savings in fuel and the need to protect the environment have become a priority, it is desirable to produce mixtures having good mechanical properties, in particular a hysteresis which is as low as possible, in order to be able to process them in the form of rubber compositions which can be used in the manufacture of various semi-finished products participating in the composition of tire casings and in order to obtain tires having a reduced rolling resistance.

#FIG. 1 shows the dynamic properties and the Mooney viscosity of compositions comprising different diene elastomers.

#In the present description, unless expressly indicated otherwise, all the percentages (%) shown are % by weight. Furthermore, any interval of values denoted by the expression “between a and b” represents the range of values extending from more than a to less than b (that is to say, limits a and b excluded), whereas any interval of values denoted by the expression “from a to b” means the range of values extending from a up to b (that is to say, including the strict limits a and b).

#The term “functionalization of the chain ends to at least 70 mol % by an amine function” is understood to mean a molar degree of functionalization at the chain end of at least 70%, with respect to the number of moles of chain end. In other words, after the polymerization of the monomers, at least 70 mol % of the living chains synthesized bear, at the non-reactive end of the chain, an amine function resulting from the polymerization initiator.

#This thus means that at least 70 mol % of the chain ends of the modified diene elastomer are functionalized by an amine function and that, in particular, at least 70 mol % of the chain ends of the entity functionalized in the middle of the chain by an alkoxysilane group, optionally partially or completely hydrolysed to give silanol, bearing an epoxide function and the silicon atom of which bonds the two pieces of the chain, are functionalized by an amine function.