Process for the polymerization of cyclic diorganopolysiloxanes w

Details Process for the polymerization of cyclic diorganopolysiloxanes w Process for the polymerization of cyclic diorganopolysiloxanes w

1977-07-06

1979-06-05

Shaver, Paul F.

Chemistry of carbon compounds

Miscellaneous organic carbon compounds

C-metal

C07F 708

Patent

active

041573374

ABSTRACT:
Diorganopolysiloxane homo- and copolymers having a viscosity from 50 to 200,000,000 centipoise at 25.degree. C., are produced by (A) reacting a composition of (i) a first cyclic siloxane having 3 to 6 units alone or admixed with (ii) a second cyclic tetrasiloxane having 3 to 6 units, (i) being present in an amount of 30 to 100 mol % of the composition, at a temperature in the range of 90.degree. to 150.degree. C. and in the presence of 5 to 500, preferably 5 to 50 parts per million, as KOH, of a catalyst comprising (a) KOH complexed with a molar equivalent of a cyclic polyesther, or (b) a silanolate of KOH complexed with a molar equivalent of a cyclic polyether and (B) neutralizing the catalyst in the reaction mixture after equilibrium has been reached. Especially useful products of the process are homopolymers and copolymers including siloxane chain units of the formula R R.sup.1 SiO wherein R.sup.1 is alkyl, halogenated alkyl or cycloalkyl, and preferably, perfluoroalkyl, and R is the same as R.sup.1 and, in addition, methyl, ethyl, vinyl or phenyl.

REFERENCES:
patent: 3002951 (1961-10-01), Johannson
patent: 3050492 (1962-08-01), Polmanteer et al.
patent: 3584027 (1971-06-01), Damle et al.
patent: 3661962 (1972-05-01), Geipel
patent: 3779987 (1973-12-01), Razzano
Boileau et al., "Polymer Letters Edition", vol. 12, pp. 217-220 (1974).

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