| 摘要 |
<p>PURPOSE:To obtain a polyester resin for a toner binder excellent in blocking resistance, low-temp. fixability, offset resistance, and storage stability and having a good grindability and a low moisture absorbency by specifying the amts of a tribasic or higher polycarboxylic acid and an arom. glycol and keeping the gel fraction lower than a specified value. CONSTITUTION:The resin is produced by condensing a dicarboxylic acid or its lower ester, an aliph. glycol, an arom. glycol of the formula (wherein R is 3C or lower alkylene; and x and y are each an integer of 1 or higher provided that the mean value of x+y is 2-7) in an amt. of 40mol.% or higher of the total amt. of all the reactants, and a tribasic or higher carboxylic acid, its anhydride, of its lower ester in an amt. of 15mol.% of the total amt. of all the reactants. The resin is a cross-lnked polymer having a Tg of 45-75 deg.C, an acid value of 2.0mgKOH/g or lower, and a gel fraction of lower than 3% and has a good balance among blocking resistance, low-temp. fixability, and offset resistance, a good grindability, a low moisture absorbency, and an excellent storage stability.</p> |
