METHOD FOR PREPARING POLYORGANOSILOXANES (POS) WITH THIOL FUNCTIONS, POS OBTAINABLE BY THIS METHOD AND THEIR USE PARTICULARLY IN RUBBER MATERIALS

摘要

Method for preparing multi-functionalised polyorganosiloxanes containing polar alkoxyl groups, and groups, each of which has a thiol group, said polymers having formula (I) is claimed. A-[Si(R)(X)-O]m-[Si(R)(Y)-O]n-[Si(R)(Z)-O]p-[Si(R)(W)-O]q -B R = 1-6C alkyl, or phenyl; X = 1-15C alkoxyl; Y = chain R' containing ethylenic double bond; where R' = 2-30C with optional oxygen atoms with chain termination of type -C(R1)=C(R2)(R3) or intermediate unsaturation such as -C(R4)=C(R5)- in which R1-R5 = H or 1-3C alkyl; Z = chain R" linked to SH group of type e.g. -C(H)(R1)-C(R2)(R3)-SH, or -C(SH)(R1)-C(R2)(R3)-H; W = -R"-(S)i-R"-Sitriple bound where i >=1 and Sitriple bound belongs to another or the same polyorganosiloxane chain; m + n + p +q = 2-300; m = 1-150; n = 0-85; p = 1-100; q = 0-25; A = radical of type (R)3Si-O-; and B = radical of type -Si(R)3. Method involves reaction of hydrogen sulphide with copolymer of formula (II). A-[Si(R)(X)-O]a-[Si(R)(Y)-O]b-B (II) a = m and b = n + p + q. The reaction is carried out in presence of catalyst based on one or more free radical initiators at a temperature = 23-150[deg]C. Also claimed are polyorganosiloxanes (POS) prepared by the method; use of the (POS) as coupling agent; and compositions containing white elastomer filler using said agent.