Silane-mediated enhancement of rubber storage stability

A process for preparing a branched elastomeric polymer, said process comprising:

• (a) polymerizing at least one conjugated diene and a compound of Formula 1 as defined below, and optionally one or more aromatic vinyl monomers, in the presence of an initiator compound,
• (a′) polymerizing at least one conjugated diene and optionally one or more aromatic vinyl monomers in the presence of an initiator compound obtained by reacting a compound of Formula 1 as defined below with an organo-alkali metal compound, or
• (a″) reacting a living polymer, obtained by anionically polymerizing at least one conjugated diene and optionally one or more aromatic vinyl monomers, with a compound of Formula 1 as defined below,
• (A)-Bn (Formula 1)
• wherein
• A is an organic group having at least two amino groups;
• each B is independently selected from a group —Si(R1)(R2)(R3), wherein R1, R2 and R3 are each independently selected from vinyl, butadienyl, methyl, ethyl, propyl, butyl, hexyl, octyl, phenyl and benzyl, with the proviso that at least one of R1, R2 and R3 is selected from vinyl and butadienyl, wherein each group B is a substituent of an amino group of group A;
• at least two of the amino groups of group A are each substituted with at least one group B;
• n is an integer of at least 2;
• and
• all amino groups in group A are tertiary amino groups;
• wherein (a), (a′) and (a″) is carried out in the presence of a stabilizer compound of Formula 2 as defined below:
• wherein
• R′ is independently selected from C1-C12 alkyl, C2-C12 alkenyl, C6-C18 aryl and C7-C18 alkylaryl, wherein the two R′ groups may be connected to form a ring and the ring may contain, further to the Si-bonded nitrogen atom, one or more of an oxygen atom, a nitrogen atom, an >N(C1-C6 alkyl, C6-C18 aryl, C7-C18 alkylaryl) group and a sulfur atom;
• R″ is selected from C1-C6 hydrocarbyl;
• R′″ is independently selected from C1-C18 hydrocarbyl;
• Ra, Rb and Rc are independently selected from hydrogen, methyl, ethyl and vinyl;
• x is an integer selected from 1 and 2;
• y is an integer selected from 0, 1 and 2;
• z is an integer selected from 0, 1 and 2;
• and x+y+z=3;
• m is selected from 0 and 1;
• with the proviso that, when none of Ra, Rb and Rc is vinyl, then m=0.