METHOD OF PRODUCING PLASTICISED POLYVINYL ALCOHOL, AND ITS USE

摘要

The method of producing plasticised polyvinyl alcohol by mixing polyvinyl alcohol in the presence of an organic plasticiser and water in a quantity which is insufficient to dissolve the polyvinyl alcohol under normal conditions, includes the steps of: i) pre-plasticising the polyvinyl alcohol at a maximum temperature no higher than its softening point so as to produce a pre-plasticised polyvinyl alcohol having a melting point below the softening point of the polyvinyl alcohol used, and ii) further processing the pre-plasticised polyvinyl alcohol thus produced at a temperature above its melting point, under shear-stress conditions and for a period of time such as to produce a substantially homogeneous melt.