| 摘要 |
PURPOSE:To provide a copolymer which can give an undercoat excellent in adhesion to gelatin, water resistance, etc., by using terephthalic acid/isophthalic acid mixture, a sulfonate-containing dicarboxylic acid, an alicyclic dicarboxylic acid and ethylene glycol as the main components. CONSTITUTION:A polyester copolymer is produced by copolymerizing an acid component containing terephthalic acid (esterifiable derivative) and isophthalic acid (esterifiable derivative) in a molar ratio of 30/70-70/30, 5-15mol%, based on the total dicarboxylic acid component, sulfonate-containing dicarboxylic acid (esterifiable derivative), e.g. sodium 5-sulfoisophthalate, and an alicyclic dicarboxylic acid (esterifiable derivative), e.g. 1,4-cyclohexanedicarboxylic acid, with a glycol component containing at least 50mol% ethylene glycol. This copolymer can be suitably used for the production of especially an undercoat of a polyester film. |
