| 摘要 |
<p>PURPOSE:To obtain a lowly hygroscopic polyester resin well balanced among offset resistance, blocking resistance and low-temperature fixability by specifying the content of an at least tribasic carboxylic acid and an aromatic glycol. CONSTITUTION:The polyester resin is prepared by poly-condensing a carboxylic acid component comprising a dicarboxylic acid or its lower alkyl ester (A) and an at least tribasic carboxylic acid or its anhydride or lower alkyl ester (B) with a glycol component comprising an aliphatic glycol (C) and an aromatic glycol (D) of the formula wherein R is 3 C or lower alkylene; x and y are each an integer of 1 or greater; and x+y is 2-7 on the averaged. The constitution ratio is such that 40-70mol%, based on the whole carboxylic acid component, component A, 30-60mol%, based on the whole carboxylic acid component, component B, 2-20mol%, based on the whole glycol component, component C and 80-98mol%, based on the whole glycol component, component D are present. This polyester has a glass transition temperature of 50-75 deg.C, an acid value of 2.0mgKOH/g or below, and a gel fraction of below 3%.</p> |
