METHOD FOR MANUFACTURING A BRANCHED POLY(HYDROXYL ACID)

摘要

The invention pertains to an improved method for synthesizing a branched poly(hydroxyl acid) polymer comprising effecting polycondensation reaction of a monomer mixture comprising: (i) at least one hydroxyl acid having only one hydroxyl group and only one carboxylic acid group [hydroxyacid (A)]; (ii) at least one polyol comprising at least three hydroxyl groups and being free from carboxylic acid group [polyol (H)]; (iii) at least one polyacid comprising at least three carboxylic acid groups and being free from hydroxyl groups [polyacid (O)]; and (iv) at least one carboxylic acid having one or two carboxylic acid groups and being free from hydroxyl group [acid (C)], wherein the amount of said acid (C) is such that the number of carboxylic acid groups thereofis comprised between 0.0001 to 0.010 % with respect to the number of hydroxyl groups of hydroxyacid (A).