Patent ID: 6451964
Filing Date: 2002-09-17
Classification: C08F,C08L

Abstract:
A method for removing a hydrocarbon solvent from a hydrocarbon solvent solution of a hydrogenated block copolymer,said hydrogenated block copolymer being obtained by hydrogenating a block copolymer comprising at least one polymer block composed mainly of vinyl aromatic monomer units and at least one polymer block composed mainly of conjugated diene monomer units, wherein the weight ratio of said vinyl aromatic monomer units to said conjugated diene monomer units is in the range of from 5/95 to 95/5, said hydrogenated block copolymer having a degree of hydrogenation of 30% or more with respect to the double bonds in said conjugated diene monomer units, said method comprising the steps of: (1) mixing a hydrocarbon solvent solution of said hydrogenated block copolymer with heated water to obtain a dispersion of said hydrocarbon solvent solution in said heated water, wherein said dispersion is not emulsified, and (2) introducing said dispersion into a steam stripping vessel containing heated water, wherein said dispersion is spouted into the gaseous phase in said steam stripping vessel toward the surface of the heated water in said steam stripping vessel under conditions wherein the vapor pressure P1 (MPa) of said dispersion and the pressure P2 (MPa) of said gaseous phase in said steam stripping vessel satisfy the following formula: P1&gE;P2 thereby effecting a steam stripping of said dispersion to remove said hydrocarbon solvent from said dispersion and obtain porous crumbs of said hydrogenated block copolymer.