Patent ID: 6365710
Filing Date: 2002-04-02
Classification: B29C,C08F,C08G

Abstract:
A method for removing volatile components from a solid polymeric material, said method comprising:Step (A) introducing a solid polymeric material comprising water into an extruder, said extruder comprising; (i) a primary kneading and melting section, said primary kneading and melting section consisting essentially of forward flighted kneading elements and optionally, forward flighted conveying elements; (ii) a first vacuum vent located downstream of said primary kneading and melting section; (iii) a secondary melt kneading section located downstream of the first vacuum vent; and (iv) a second vacuum vent located downstream of said secondary melt kneading section; Step (B) heating and shearing said polymeric material in said primary kneading and melting section to form a polymer melt comprising water; Step (C) removing a portion of the water from the polymer melt through said first vacuum vent to form a partially devolatilized polymer melt; Step (D) subjecting the partially devolatilized polymer melt to additional melt kneading in a secondary melt kneading section; and Step (E) removing an additional amount of water from the partially devolatilized polymer melt at said second vacuum vent.