Patent ID: 6737495
Filing Date: 2004-05-18
Classification: C08G

Abstract:
A method for preparing polyorganosiloxanes (POS) by (a) polycondensation of monosilanes and/or of acyclic siloxanes carrying reactive Siâ€”OR units with R&boxH;H or alkyl, or by (b) redistribution/polycondensation of siloxane compounds based on cyclosiloxanes and optionally acyclic siloxanes which may carry reactive Siâ€”OR units as defined above, Siâ€”H units or Si-alkenyl units, in the presence of an acid catalyst, said method using at least one catalyst of the following formula (I):(CmF2m+1SO2)nAâ€ƒâ€ƒ(I) in which:&Dgr; m is an integer greater than or equal to 1; &Dgr; n is an integer equal to 1 or 2 and A represents OH, NH2 or NH with: (i) n=1 and A=OH or (ii) n=1 and A=NH2 or (iii) n=2 and A=NH; &Dgr; with the proviso according to which: &compfn; when this catalyst corresponds to the formula I(i), it is supported on an inert material, in a quantity by mass QM expressed as % by weight relative to the total mass (a) of the monosilanes and/or acyclic siloxanes or (b) of the starting siloxane compounds, which is equal to or less than 1.5; and &compfn; when this catalyst corresponds to formula I(iii): either it is supported on an inert material in the case of the preparation of polyorganosiloxanes (POS) by (a) polycondensation of monosilanes and/or acyclic siloxanes or by (b) redistribution/polycondensation of siloxane compounds based on cyclosiloxanes and optionally acyclic siloxanes.