Method for preparing polyorganosiloxanes by polymerization catalyzed by a catalytic system based on triflic acid or triflic acid derivatives

Abstract

The invention concerns a method for preparing polyorganosiloxanes (POS) by (a) condensation polymerisation of monosilanes and/or acyclic siloxanes bearing reactive Si—OR units with R═H, or alkyl, or by (b) redistribution/condensation polymerisation of siloxane compounds based on cyclosiloxanes and/or acyclic siloxanes capable of bearing reactive Si—OR units such as defined above, Si—H or Si-alkenyl units, in the presence of an acid catalyst. Said method is characterised in that it consists in using at least a catalyst of the following formula (I) (C F SO ) A wherein: m is an integer not less than 1; n is an integer equal to 1 or 2 and A represents OH, NH or NH with: (i) n=1 and A=OH or (ii) n=1 and A=NH or (iii) n=2 and A=NH; provided that, when said catalyst corresponds to formula (I) (i), it is brought in the presence of an inert support in mass amount QM, expressed in weight % relative to the total mass (a) of monosilanes and/or acyclic siloxanes or (b) of the initial siloxane compounds, which is not more than 1.5. The invention also concerns a catalyst for use in the preparation of POS by said process (a) or (b) consisting of at least a compound selected among the compound of formula I(ii), the compound of formula I(iii) and mixtures thereof.