| 摘要 |
PURPOSE:To provide the titled composition effective to prevent the generation of plane defects, by dissolving a specific unsaturated polyester in a styrene (derivative) and a mono or diester of an unsaturated dibasic acid at a specific ratio, and adding maleic anhydride to the dissolved composition. CONSTITUTION:(A) An unsaturated polyester having a molecular weight of 500-8,000 per 1mol of the unsaturated group and obtained by the reaction of (i) an acid component containing an unsaturated dibasic acid and/or acid anhydride (e.g. maleic acid) and if necessary other polybasic acid (e.g. phthalic anhydride) and (ii) an alcohol component, is dissolved in (B) styrene and/or its derivative, and the solution is added with (C) a monoester and/or diester of an unsaturated dibasic acid. The amounts of the components A, B and C are selected to satisfy the formula (a, b and c are molar numbers of unsaturated groups in the components A, B and C, respectively). The objective composition can be produced by dissolving (D) 0.5-10pts.(wt.) of maleic anhydride to 100pts. of the composition produced by the above process under heating at 54-60 deg.C.
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