| abstract |
The invention concerns the use of a compound comprising a polyfunctional polyorganosiloxane (POS) bearing at least a hydroxyl radical and/or at least an alkoxyl radical and at least an activated double ethylene bond, as coupling agent (white filler-elastomer) in rubber compositions based on isoprene elastomer(s) comprising a white filler as reinforcing filler. The invention also concerns isoprene elastomer compositions obtained by using said coupling agent, and elastomeric articles having a body comprising said compositions. The coupling agent is a compound comprising a POS with similar or different units of formula (R2)aYbXcSiO[4-a(a+b+c)]/2 wherein: (1) R2 is a monovalent hydrocarbon group; (2) Y represents a OH or an alkoxyl; (3) X is a function comprising an activated double ethylene bond selected among a maleimide, isomaleimide, maleamic acid, maleamic ester and acrylamide function; (4) a = 0, 1, 2 or 3, b = 0, 1, 2 or 3, c = 0 or 1, the sum a + b + c is different from 0 and ≤ 3; (5) function Y rate is ≥ 0.8 %, (6) function X rate is ≥ 0.4 % (rate = number of functions for 100 Si atoms). |