JPS6474263A - Flame-retarding polyurethane composition - Google Patents

Abstract

PURPOSE:To obtain the title melt-moldable composition which can give a product excellent in flame retardancy and mechanical properties, by mixing a thermoplastic polyurethane with a specified hydroxy compound and a phosphorous (phosphoric) ester. CONSTITUTION:A halogenated bisphenol of formula I (wherein R2-3 are each H, CH3, or C2H5, X is Br or Cl, and m is 2-4) is reacted with an epoxide compound (e.g., epichlorohydrin) to obtain a halogenated epoxy-modified hydroxylated polymer (B) of formula II (wherein R1 is H or a group of formula III or IV, and n is 5-20). A thermoplastic polyurethane (A) of an intrinsic viscosity of 0.6-1.2, obtained by polymerizing a polymer diol of an average-MW of 500-3,000 with an organic diisocyanate and a compound of an MW >=300, having two active hydrogen atoms is mixed with a flame retardant comprising of 5-20wt.% component B and a phosphoric and/or phosphorous ester (C) in an amount to give a P to X ratio of 1/5-20 (wherein X is the amount of the halogen atoms and P is the amount of component C) and, optionally, a metal compound (D) (e.g., Sb2O3) as a flame retarding aid in an amount to give an M to X ratio of 1/1-5 (wherein M is the amount of component D).