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US 4,289,685 AGranted
Process for the preparation of flame-resistant polycarbonates
AssigneeBayer Aktiengesellschaft
InventorsFrank Druschke, Dieter Margotte, Erhard Tresper, Ludwig Bottenbruch, Wolfgang Cohnen, Uwe Hucks
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Abstract
The invention relates to a process for rendering flame-resistant the thermoplastic aromatic polycarbonates prepared by a solution process, characterized by dispersing an aqueous solution of salt-like flameproofing agent in a washed and neutral polycarbonate/organic solvent system.
Claims4
In the process of rendering flame-resistant the thermoplastic aromatic polycarbonates prepared by a solution process, the improvement comprising steps
- (i) washing the polycarbonate/organic solvent system until neutral and free of electrolytes and
- (ii) adding to the neutral and electrolyte free system an effective amount of an aqueous solution of a salt-like flameproofing agent and
- (iii) dispersing said aqueous solution, in the form of particulates of less than 2 .mu.m in diameter, in said system and
- (iv) isolating the polycarbonate/salt-like flameproofing agent composition by evaporating the water and the organic solvent.
1 more element
Dependencies are inferred from the claim text.