| abstract |
The present invention relates to a method for preparing a biodegradable polyester copolymer resin with improved hydrolysis resistance. The method according to the present invention comprises the steps of: first reacting an aliphatic dihydroxy compound and an aliphatic dicarboxylic acid compound; and further adding an aromatic dicarboxylate after the first reaction to secondarily react the same, wherein a short-chain alcohol type branching agent is added to a first or a second esterification reaction. The method allows slow esterification by an acid to proceed first, and then applies an aromatic dicarboxylate compound having no acid groups, thereby effectively controlling unreacted products or partially reacted products, which affect the acidity of a product, during the reaction, and thus it is possible to effectively control the acidity even without an excessive amount of excessive BDO, an excessive amount of chain extender or an expensive anti-hydrolysis agent, thereby improving hydrolysis resistance. In addition, it is possible to improve tear strength by minimizing branching agent content used therein. |