METHOD OF PREVENTING CORROSION IN CONNECTION WITH EXTRUSION OF MIXTURES CONTAINING POLYVINYL CHLORIDE AND WOOD FLOUR OR SIMILAR CELLULOSIC MATERIAL AND ANALOGOUS MIXTURES CONTAINING POLYSTYRENE OR ACRYLONITRILE BUTADIENE STYRENE RESIN RESPECTIVELY

摘要

1409187 Preventing corrosion during extrusion SONESSON PLAST AB 30 Oct 1973 [3 Nov 1972 1 Dec 1972] 50512/73 Heading B5A [Also in Division C3] Corrosion and wear during extrusion of a composition of polyvinyl chloride, polystyrene or acrylonitrile/butadiene/styrene resin with cellulosic material, for example, wood flour, is prevented by effecting the extrusion in the presence of a gaseous alkaline compound. This is done by incorporating a compound which will volatalize or degrade to give a gaseous alkali during extrusion in the composition. In examples the additive was urea, monoethanolamine, triethanolamine or ammonium sulphate. Polyvinyl chloride compositions also contained lead and calcium stearate and chalk. Alternatively gaseous ammonia could be introduced into the extruder directly.