PURPOSE: To prepare the titled polymer having excellent curability and giving a cured product having excellent mechanical properties, by reacting phthalic anhydride with a dihydric alcohol at a specific ratio, adding an unsaturated dicarboxylic acid anhydride, etc. to the reaction mixture, and carrying out the ring-opening addition polymerization reaction.
CONSTITUTION: The objective polymer is prepared by (1) reacting (A) phthalic anhydride with (B) a dihydric alcohol (preferably ethylene glycol) at a molar ratio of 2:1W1:2, (2) adding (C) an α,β-unsaturated dicarboxylic acid anhydride (preferably maleic anhydride) and (D) an alkylene oxide (preferably ethylene oxide, etc.) to the above reaction mixture and subjecting to the ring-opening addition polymerization, and (3) carrying out the polycondensation of the unsaturated oligoester obtained by the ring-opening addition polymerization. The component (C) is preferably molten by heating at the temperature of the reaction mixture before adding to the reaction mixture, and the atmosphere is sufficiently substituted with an inert gas to prevent the discoloration of the polymer.
HASEGAWA TAKASHI
MIKI MINORU
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