| 摘要 |
PURPOSE:To provide the title compsn. which is lowly shrinkable and gives molded items having excellent surface smoothness, by blending a specified unsaturated polyester resin dissolved in an ethylenically unsaturated monomer with a styrene/butadiene/styrene block copolymer. CONSTITUTION:An unsaturated polyester (A) having an MW of not higher than 300 per double bond (e.g., one obtd. by condensing maleic anhydride with propylene glycol) is reacted with a polybutadiene derivative (B) having hydroxyl groups [e.g., alpha,omega-polybutadiene glycol of the formula (wherein n is 15-54)] in a weight ratio of B to (A+B) of 0.01-0.2. The reaction product is dissolvent in an ethylenically unsaturated monomer (C) (e.g., styrene). The resulting unsaturated polyester resin is blended with a styrene/butadiene/styrene block copolymer (D) to obtain the title compsn. According to the above method, a phase separation of the component D as a shrinkage controlling agent from the unsaturated polyester resin can be inhibited and molded products having excellent surface smoothness can be obtd.
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