VISCOSITY MODIFIER FOR UNSATURATED POLYESTER RESIN, COMPOSITE MATERIAL AND MOLDING USING THE SAME, AND METHOD FOR MANUFACTURING THE VISCOSITY MODIFIER FOR UNSATURATED POLYESTER RESIN

摘要

PROBLEM TO BE SOLVED: To provide a viscosity modifier for an unsaturated polyester resin capable of favorably impregnating an unsaturated polyester resin composition with a fiber material while improving surface smoothness of a molding.SOLUTION: A styrene fumaric acid copolymer as the viscosity modifier for an unsaturated polyester resin is obtained by subcritical water decomposition of a material containing an unsaturated polyester resin cured product obtained by the reaction of an unsaturated polyester resin and a crosslinking agent comprising a styrene at a temperature of less than a thermal decomposition temperature of the unsaturated polyester resin cured product.