Process for preparing shelf-stable curable polysilazanes, and polysilazanes prepared thereby
A process for preparing curable oligomeric and/or polymeric polysilazanes comprises (a) forming at least one dihalosilane-base adduct by reacting at least one dihalosilane with at least one base; (b) optionally, combining at least one dihalosilane-base adduct and at least one organodihalosilane; and (c) carrying out ammonolysis of at least one dihalosilane-base adduct or of the resulting combination of at least one dihalosilane-base adduct and at least one organodihalosilane; with the proviso that the base (1) is used for the dihalosilane-base adduct formation in a limited amount that is less than or equal to twice the stoichiometric amount of silicon-halogen bonds in the dihalosilane or (2) is used for the dihalosilane-base adduct formation in excess of this limited amount and, prior to the ammonolysis, the total amount of the resulting reacted and unreacted base is reduced to no more than this limited amount.
3M Innovative Properties Company
C
C08G
inventional
Yu George G. I.
Yang Moore