Method to make a solid polymeric phosphate and resinous compositions containing it

Abstract

Disclosed is a method for the preparation of polymeric phosphate flame retardants with a molecular weight of at least about 1500 and a softening temperature of at least about 10° C. comprising the steps of (a) reacting a phosphorus oxyhalide with a monohydroxyaromatic compound, (b) removing substantially all of any remaining phosphorus oxyhalide; (c) reacting the monoaryldichlorophosphate product with a dihydroxyaromatic compound and (d) reacting the product of step (c) with a monohydroxyaromatic compound. The solid polymeric flame retardant has a linear structure and less than 10 ppm halogen bound to phosphorus. Also disclosed are resinous compositions comprising the solid polymeric phosphate made by the method of the invention and at least one other polymeric resin.

Dependencies are inferred from the claim text.