Resins for electrohotographic toners

A resin for electrophotographic toner comprising a degradable polyester resin which is one prepared by reacting a semicrystalline poly( .alpha.-hydroxycarboxylic acid), having a number-average molecular weight ranging from 1000 to 7000 and prepared by direct dehydration-polycondensation of an .alpha.-hydroxycarboxylic acid, with a polyol having at least three hydroxyl groups in the molecule and wherein the degradable polyester has a rate of the terminal hydroxyl groups of not less than 90% of the total terminal groups of the polyester.

A resin for electrophotographic toner comprising a degradable polyester which is an urethane-modified polyester produced by reacting a diisocyanate with a polyester, which is prepared by reacting a semicrystalline poly( .alpha.-hydroxycarboxylic acid) having a number-average molecular weight ranging from 2000 to 7000 and prepared by direct dehydration-polycondensation of an .alpha.-hydroxycarboxylic acid with a polyol having at least three hydroxyl groups in the molecule, so that isocyanate groups are added to the polyester in an amount of not less than 0.8 molar equivalent per molar equivalent of the hydroxyl group of the latter.

A resin for electrophotographic toner comprising a degradable polyester resin which is one prepared by reacting a semicrystalline poly-(.alpha.-hydroxycarboxylic acid), having a number-average molecular weight ranging from 100 to 7000 and prepared by direct dehydration-polycondensation of an .alpha.-hydroxycarboxylic acid, with a polycarboxylic acid having at least three carboxyl groups in the molecule and which has a rate of terminal carboxyl groups of not less than 90% of the total terminal groups of the polyester.