Preparation of polyvinyl alcohol

Claim 1

A METHOD FOR THE CONTINUOUS MANUFACTURE OF POLYVINYL ALCOHOL WHICH COMPRISES PREPARING AN ESSENTIALLY ANHYDROUS ALCOHOLIC SOLUTION OF AN ALKALI METAL HYDROXIDE OF THE GROUP CONSISTING OF LITHIUM, SODIUM AND POTASSIUM HYDROXIDES, AND AN ESSENTIALLY ANHYDROUS ALCOHOLIC SOLUTION OF POLYVINYL ACETATE, SIMULTANEOUSLY INTRODUCING SAID SOLUTIONS INTO A MIXING CHAMBER AND THOROUGHLY MIXING SAID SOLUTIONS, WHILE THE RESULTANT MIXTURE IS IN A FLUID STATE CONTINUOUSLY FLOWING IT OUT ONTO AN INERT SURFACE CONTINUOUSLY MOVING AWAY FROM THE SOURCE OF MIXING, ALLOWING THE MIXTURE TO FORM A GEL ON SAID SURFACE AND AFTER APPROXIMATELY TWICE THE GELLING TIME OF SAID MIXTURE AND BEFORE SUBSTANTIAL SYNERESIS HAS TAKEN PLACE CONTINUOUSLY REMOVING THE GEL FROM THE SURFACE AND IMMEDIATELY THEREAFTER COMMINUTING THE GEL, ALLOWING THE COMMINUTED GEL TO SYNERESE FOR AT LEAST ONE HOUR AND WASHING IT WITH WATER AT A TEMPERATURE BELOW THE MINIMUM SOLUTION TEMPERATURE OF THE GEL.

Claim 2

A METHOD FOR THE CONTINUOUS MANUFACTURE OF POLYVINYL ALCOHOL WHICH COMPRISES PREPARING AN ESSENTIALLY ANHYDROUS ALCOHOLIC SOLUTION OF AN ALKALI METAL HYDROXIDE OF THE GROUP CONSISTING OF LITHIUM, SODIUM AND POTASSIUM HYDROXIDES, AND AN ESSENTIALLY ANHYDROUS ALCOHOLIC SOLUTION OF POLYVINYL ACETATE, SIMULTANEOUSLY INTRODUCING SAID SOLUTIONS INTO A MIXING CHAMBER AND THOROUGHLY MIXING SAID SOLUTIONS, WHILE THE RESULTANT MIXTURE IS IN A FLUID STATE CONTINUOUSLY FLOWING IT OUT ONTO AN INERT SURFACE CONTINUOUSLY MOVING AWAY FROM THE SOURCE OF MIXING, ALLOWING THE MIXTURE TO FORM A GEL ON SAID SURFACE AND AFTER APPROXIMATELY TWICE THE GELLING TIME OF SAID MIXTURE AND BEFORE SUBSTANTIAL SYNERESIS HAS TAKEN PLACE CONTINUOUSLY REMOVING THE GEL FROM THE SURFACE AND IMMEDIATELY THEREAFTER COMMINUTING THE GEL, ALLOWING THE COMMINUTED GEL TO SYNERESE FOR AT LEAST ONE HOUR AND WASHING IT WITH WATER AT A TEMPERATURE BELOW THE MINIMUM SOLUTION TEMPERATURE OF THE GEL.