Impact resistant moldable polyacetal resin compositions and processes for making same

Abstract

Moldable polyacetal resin compositions include a polyacetal base resin and an impact resistant effective amount of a thermoplastic polyurethane resin melt-blended therewith. The polyacetal base resin is itself a mixture of (A.sub.1) a low hydroxyl-containing (LHC) polyacetal resin having less than 50 mmol/kg hydroxyl groups in its molecule, and (A.sub.2) a high hydroxyl-containing (HHC) polyacetal resin having greater than 50 mmol/kg hydroxyl groups in its molecule. The polyacetal resin compositions optionally may include a reactive compound having at least one reactive moiety to further enhance the desirable properties that are achieved by inclusion of the HHC polyacetal resin. The components are melt-blended and subjected to conditions (which typically occur during the melt-blending step) to allow the polyurethane resin to react with the HHC polyacetal resin. As a result, a compatibilizing copolymer is formed in situ so that the polyurethane resin is compatabilized with the LHC polyacetal resin thereby minimizing delamination and increasing weld strengths of molded articles formed of the same.

Dependencies are inferred from the claim text.