Process for preparing linear silanol chain-stopped diorganopolysiloxanes

Claim 1

THE PROCESS OF PREPARING A LINEAR SILANOL CHAINSTOPPED DIORGANOPOLYSILOXANE HAVING A PREDETERMINED SILANOL CONTENT AND HAVING A VISCOSITY IN EXCESS OF 1,000 CENTISTOKES AND UP TO ABOUT 50,000,000 CENTISTOKES WHEN MEASURED AT 25*C., WHICH PROCESS CONSISTS ESSENTIALLY OF HEATING UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS AT A TEMPERATURE OF FROM 80 TO 180*C. IN CONTACT WITH A CATALYTIC AMOUNT OF AN ALKALINE ORGANOPOLYSILOXANE REARRANGEMENT AND CONDENSATION CATALYST (1) A CYCLIC DIORGANOPOLYSILOXANE CONTAINING FROM 3 TO 9 DIORGANOSILOXANE UNITS PER MOLECULE WITH (2) A MEMBER SELECTED FROM THE CLASS CONSISTING OF DIPHENYLSILANEDIOL AND A LINEAR SILANOL CHAIN-STOPPED DIORGANOPOLYSILOXANE HAVING A VISCOSITY BELOW ABOUT 1,000 CENTISTOKES WHEN MEASURED AT 25*C., THE PROPORTIONS OF (1) AND (2) BEING SELECTED SO AS TO PROVIDE SAID PREDETERMINED SILANOL CONTENT, THE ORGANO GROUPS OF THE DIORGANOPOLYSILOXANES BEING SELECTED FROM THE CLASS CONSISTING OF MONOVALENT HYDROCARBON RADICALS, HALOGENATED MONOVALENT HYDROCARBON RADICALS AND CYANOALKYL RADICALS.