Polycondensation of hydroxysilylated polysiloxanes
AssigneeRhone-Poulenc Industries
InventorClaude Millet
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Abstract
High molecular weight organopolysiloxanes are rapidly prepared, without formation of the low molecular weight polysiloxanes, by polycondensing a hydroxysilylated polysiloxane in the presence of a catalytic amount of a catalyst system including (i) an alkali or alkaline earth metal, and (ii) a polyheteromacropolycyclic co-catalyst having the structural formula: ##STR1## wherein .SIGMA. is a divalent radical having the structural formula ##STR2## or a divalent radical having the structural formula: ##STR3## further wherein each R, which may be identical or different, is a divalent hydrocarbon radical, each Q, which also may be identical or different, is a divalent hydrocarbon radical, an oxygen atom or a sulfur atom, and m, n and p are each integers equal to 1, 2 or 3.
Claims24
A process for the preparation of a high molecular weight organopolysiloxane by polycondensation of a hydroxysilylated polysiloxane, essentially without formation of low molecular weight polysiloxane, which comprises polycondensing such polysiloxane, essentially without equilibration thereof, in the presence of a catalytic amount of a catalyst system comprising (i) an alkali or alkaline earth metal, and (ii) a polyheteromacropolycyclic cryptate co-catalyst having the structural formula:
- ##STR18##
- wherein .SIGMA. is a divalent radical having the structural formula ##STR19## or a divalent radical having the structural formula:
- ##STR20## further wherein each R, which may be identical or different, is a divalent hydrocarbon radical, each Q, which also may be identical or different, is a divalent hydrocarbon radical, an oxygen atom or a sulfur atom, and m, n and p are each integers equal to 1, 2 or 3.
Dependencies are inferred from the claim text.