| abstract |
PURPOSE:To prepare the title resin which is excellent in blocking resistance, by reacting a dicarboxylic acid, a glycol, a carboxylic acid having a valency of at least three and/or an alcohol having a valency of at least three with the addition of an arom. monocarboxylic acid in a specified amt. CONSTITUTION:A dicarboxylic acid (e.g., terephthalic acid), a glycol (e.g., ethylene glycol), a carboxylic acid having a valency of at least three (e.g., trimellitic anhydride) in an amt. of 2-30mol.% to the total carboxylic acid content and/or an alcohol having a valency of at least three (e.g., glycerin), with the addition of an arom. monocarboxylic acid (e.g., benzoic acid) in an amt. of 0.5-20mol.% to the total carboxylic acid content, in the presence of a catalyst (e.g., dibutyltin oxide), are heated under normal pressure to carry out esterification until the water formed as a by-product has thoroughly been removed by evaporation. The product is submitted to polycondensation under reduced pressure to give the title resin. |