| abstract |
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. |