Patent ID: 6833096
Filing Date: 2004-12-21
Classification: B29B,B29C,B29K,C08G

Abstract:
A method for removing volatile components from a polymer powder, wherein said polymer powder is a polycarbonate comprising structural units I wherein R1 is independently at each occurrence a halogen atom, nitro group, cyano group, C1-C20 alkyl group, C4-C20 cycloalkyl group, or C6-C20 aryl group; n and m are independently integers 0-4; and W is a bond, an oxygen atom, a sulfur atom, a SO2 group, a C1-C20 aliphatic radical, a C6-C20 aromatic radical, a C6-C20 cycloaliphatic radical or the group wherein R2 and R3 are independently a hydrogen atom, C1-C20 alkyl group, C4-C20 cycloalkyl group, or C4-C20 aryl group; or R2 and R3 together form a C4-C20 cycloaliphatic ring which is optionally substituted by one or more C1-C20 alkyl, C6-C20 aryl, C5-C21 aralkyl, C5-C20 cycloalkyl groups or a combination thereof, said method comprising:Step (A) introducing the polymer powder comprising water into an extruder, said extruder comprising; (i) a powder conveying section; (ii) a powder seal section located downstream of said powder conveying section; (iii) a kneading and melting section located downstream of said powder seal section; and (iv) a vacuum vent located downstream of said kneading and melting section; Step (B) conveying the polymer powder through said powder seal section; Step (C) heating and shearing the polymer powder in said kneading and melting section to form a polymer melt comprising water; and Step (D) subjecting said polymer melt to vacuum venting at said vacuum vent.