| 摘要 |
PURPOSE:To improve the moldability of resin coated sand and the casting mold strength at elevated temp. in an unsatd. polyester resin compsn. for binding of sand by using hydrogenated bisphenol A for a polyhydric alcohol component and adding a specific metallic oxide thereto. CONSTITUTION:A titled compsn. contains an unsatd. polyester of >=50 deg.C softening point measured by a ring and ball method which is prepared by reacting alpha,beta- unsatd. dibasic acid and an acid component including satd. dibasic acid as required, with a polyhydric alcohol component in which 10-100mol% of polyhydric alcohol is hydrogenated bisphenol A, an unsatd. monomer or prepolymer having >= one polymerizable double bond in a molecule, a polymerization catalyst and an oxide of a metal of the group I -IV or VIII. The softening point of the unsatd. polyester resin obtd. by the above-mentioned method is high and the heat resistance is improved. Since the melt sticking point is improved by the addition of the above-described metallic oxide without increasing the softening point considerably, the purpose is achieved. |
