Abstract: A method of preparing a plasticised particulate polyvinyl alcohol (PVA) composition is provided, comprising: mixing, in a mixer, at a mixer speed and for a time sufficient that the mixture attains a temperature of at least 50° C.: particulate PVA resin in an amount from 80% to 90% by weight of the mixture; and plasticiser in an amount from 10% to 20% by weight of the mixture, wherein at least a portion of the plasticiser 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, thereby to obtain a plasticised particulate mixture having a moisture content in the range from 7% to 14%; preferably adding an anti-caking agent in an amount from 0.05% to 0.
May 13, 2005
Date of Patent:
May 15, 2007
Paul Anthony Taylor, Kevin Mark Goninan, Thomas Vivian Simpkins, Michael Thomas Williams, Anthony Cyril Soden