GB1513197A - Poly(butyleneterephthalate)-polyurethane blends - Google Patents

Abstract

1513197 Polyurethane; poly (butyleneterephthalate) blends MOBAY CHEMICAL CORP 18 Oct 1976 [20 Oct 1975] 43164/76 Heading C3R A low temperature impact resistant composition comprises an intimate mixture of 25 to 50 p.p.w. of poly(butyleneterephthalate) whose intrinsic viscosity [n] may be within the range 0À6 to 1À5, and 50 to 75 p.p.w. of a thermoplastic processable polyurethane which is defined as a block polymer prepared from a diisocyanate, a polyester or polyether and a chain extender and is processable by compression or injection mould. ing or extrusion. Articles may be formed from these blends by a method which comprises mixing the reactants from which the polyurethane is obtained at for example 100‹ C. to form a liquid reaction mixture; casting this mixture on to a heated surface, e.g. at 100‹ C. and allowing it to solidify; removing the thermoplastic processable polyurethane thus formed from the surface and allowing to cool; blending this polyurethane with a poly(butyleneterephthalate) and shaping the blend under heat and pressure to give the required articles. In an example 75 p.p.w. of a thermoplastic processable polyurethane prepared by reacting a polyester Mol. Wt. 2,000 obtained from adipic acid and 1,4 butane diol; ethylene glycol as chain extender and sufficient diphenylmethane diisocyanate (free HCl content 0À017 p.p.w.) to react with all the hydroxy groups in the reaction mixture and to provide a 6% by weight excess, was blended, by means of a single screw extruder, with 25 parts of poly(butyleneterephthalate). This blend was cut into pellets and moulded to provide 4 inch diameter, 0À1 to 0À125 inch thick test discs which where flexible at - 70‹ C. and had low temperature impact values 65À2 to 57À37 ft. lb. after immersion in methanol at - 70‹ C. for two minutes.