Patent ID: 8304516

Claim:
A method of continuously washing a poly(vinyl butyral) resin, comprising the steps: providing a first continuous stirred tank reactor; providing a second continuous stirred tank reactor; adding a continuous stream of poly(vinyl butyral) slurry to said first continuous stirred tank reactor; adding a first fresh solvent to said second continuous stirred tank reactor; washing said continuous stream of poly(vinyl butyral) slurry with a moving solvent in said first continuous stirred tank reactor to form a once washed poly(vinyl butyral) slurry; moving said once washed poly(vinyl butyral) slurry to said second continuous stirred tank reactor; washing said once washed poly(vinyl butyral) slurry with said first fresh solvent in said second continuous stirred tank reactor to form a twice washed poly(vinyl butyral) slurry and said moving solvent; removing said twice washed poly(vinyl butyral) slurry from said second continuous stirred tank reactor; moving said moving solvent from said second continuous stirred tank reactor to said first continuous stirred tank reactor.