Patent ID: 7217385

Claim:
A method for preparing a plasticized particulate polyvinyl alcohol (PVA) composition comprising: mixing, in a mixer, a particulate PVA resin, in an amount from 80% to 90% by weight of the mixture; and plasticizer, in an amount from 10% to 20% by weight of the mixture, wherein at least a portion of the plasticizer is water; monitoring the apparent viscosity of the mixture during mixing; and continuing mixing until the apparent viscosity of the mixture has peaked to a maximum and dropped off to a substantially constant level, to obtain a plasticised particulate mixture having a moisture content in the range from 7% to 14%; and stopping mixing, and removing the mixture from the mixer, wherein the mixing is at a speed and for a time sufficient that the mixture attains a temperature of at least 50° C.; and wherein the mixture temperature is kept below 100° C. at all times during mixing.