Patent ID: 8129454

Claim:
A method of reducing die lip build-up during profile extrusion of a thermoplastic article, comprising: profile extruding through a die a thermoplastic composition having a temperature of 220 to 240° C.; and cooling the extruded composition to form an extruded thermoplastic article; wherein the thermoplastic composition comprises 56 to 62 weight percent of a poly(arylene ether), 16 to 22 weight percent of a homopolystyrene, 7 to 13 weight percent of a hydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene, and 7 to 13 weight percent of a triaryl phosphate; wherein the thermoplastic composition comprises less than 1 weight percent of unhydrogenated poly(conjugated diene) rubber; wherein all weight percents are based on the total weight of the thermoplastic composition; wherein the thermoplastic composition exhibits an Izod notched impact strength at −30° C. of at least 6 kilojoules/meter 2 , as measured according to ISO 180 using notch configuration A, and a Vicat B value of at least 125° C., measured according to ISO 306, Method B120; wherein the profile extruding the thermoplastic composition produces an average die lip build-up per hour measured over the course of 8 continuous hours of profile extrusion of the thermoplastic composition, measured at a melt temperature of 233° C. using an annular die having an outside diameter of 24.6 millimeters and an inside diameter of 21.35 millimeters; and wherein the average die lip build-up is less than that produced by a corresponding thermoplastic composition in which the hydrogenated block copolymer is replaced by an equal weight of an unhydrogenated block copolymer.