Method of cleaning melt-processing equipment with a thermoplastic polyolefin and a bifunctional siloxane

Abstract

A method of cleaning melt-processing equipment which comprises processing in such equipment a thermoplastic composition which comprises at least one thermoplastic polyolefin and at least one siloxane-containing additive having at least two moieties, A and B, in which: (A) said additive is compatible with said polyolefin at melt extrusion temperatures but is incompatible at temperatures below melt extrusion temperatures, but each of moiety A and moiety B, if present as separate compounds, would be incompatible with said polyolefin at melt extrusion temperatures and at temperatures below melt extrusion temperatures; (B) moiety A contains at least one tetrasubstituted disiloxanylene group; (C) moiety B has at least one functional group which is a poly(oxyalkylene) moiety; (D) the molecular weight of said additive is in the range of from about 400 to about 16,000; and (E) said additive is present in said thermoplastic composition at a level of from about 3 to about 12 percent by weight, based on the weight of said thermoplastic polyolefin; in which (1) said at least one thermoplastic polyolefin is not the same polymer as last employed in the melt-processing equipment to be cleaned, and (2) the amount of thermoplastic composition and the processing time are sufficient to clean said processing equipment.

Dependencies are inferred from the claim text.