Rhodia Chimie

Jos&eacute; Martins

Jean-Roger Desmurs

G&eacute;rard Mignani

L&eacute;on Ghosez

Christian Bordone

The invention concerns a method for preparing polyorganosiloxanes (POS) by (a) condensation polymerisation of monosilanes and/or acyclic siloxanes bearing reactive Si&mdash;OR units with R&boxH;H, or alkyl, or by (b) redistribution/condensation polymerisation of siloxane compounds based on cyclosiloxanes and/or acyclic siloxanes capable of bearing reactive Si&mdash;OR units such as defined above, Si&mdash;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&equals;1 and A&equals;OH or (ii) n&equals;1 and A&equals;NH or (iii) n&equals;2 and A&equals;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.

Growing community of inventors

Rillieux, France

José Martins

Growing community of inventors

Rillieux, France

Jos&eacute; Martins

José Martins