Preparation of high solids poly(vinyl alcohol)/water solutions in a single screw extruder

摘要

A method for producing a high solids aqueous solution of poly(vinyl alcohol) in which substantially dry poly(vinyl alcohol) is first fed into a specially designed single screw extruder. Heated water is introduced through a separate entry port downstream of the feed end of the extruder. A temperature of 38 to 121 DEG C. and a back pressure of at least 20,786 kPa are applied to the extruder. The mixture of poly(vinyl alcohol) and water is conveyed through transition and metering sections of the single screw extruder to dispersive and distributive mixing sections to produce a high solids poly(vinyl alcohol) solution which is substantially free of gels. The high solids poly(vinyl alcohol) solution can be used directly in the production of products such as fibers and sheets.