Flame retardant squaring means for high molecular weight organic compounds

摘要

PURPOSE:To prepare the titled flame retardant having excellent flame retardancy, compatibility, weather resistance and heat resistance, extremely low migration tendency in a polymeric material, and giving no detrimental effect to the mechanical properties of the polymer, by blocking the terminal hydroxyl groups of the polycondensation product of a halogenated phenol. CONSTITUTION:A halogenated phenol is subjected to polycondensation in the presence of e.g. a caustic alkali and a metallic catalyst, and the resultant polycondensation product is made to react with a metallic compound having two or more functional groups reactive with the terminal hydroxyl group, e.g. halide of Mg, Al, Ca, Sn, etc. or an organic compound having two or more functional groups reactive with the terminal hydroxyl group, e.g. alkyl dihalide, phosphoric acid dihalide, cyanuric halide, etc. in the presence of a caustic alkali or in a nonpolar solvent using a Lewis acid.