CONTROL OF BIODEGRADATION RATE AND BIODEGRADABLE MULTI- LAYERED MOLDING

摘要

PROBLEM TO BE SOLVED: To enable suppressing the biodegradation rate per unit volume by mixing a polyhydroxybutyric acid having a relatively rapid biodegradation rate with an aliphatic polyester to reduce the biodegradation rate of the aliphatic polyester. SOLUTION: This method for controlling the biodegradation rate is to mix (A) an aliphatic polyester synthesized from a glycol and an aliphatic dicarboxylic acid or a polycaprolactone and (B) a poly-3-hydroxybutyric acid (preferably having >=100,000 weight-average molecular weight) for suppressing the biodegradation rate of the component A. Further it is preferable to mix the component B with the component A by 20-80%. Also, it is preferable to mix with melting and kneading in 130-250 deg.C temperature range in mixing the component B to the component A. In a multi-layered molding having outer layers consisting of the mixture at both surfaces of an inner layer consisting of the mixture of the components A and B, by changing the mixing ratio of the component B, it is possible to obtain a biodegradable multi-layered molding corresponding to its objective.