Abstract: The present invention provides a card base which is degradable by microbes in natural environment. The card base is excellent in properties necessary for card bases, such as tensile strength, impact strength, flex temperature, heat resistance, resistance to thermal expansion and contraction, blocking resistance and humidity resistance, and has rigidity, bending resistance and durability. The card base contains, as essential components, a 3-hydroxybutylate/3-hydroxyvalerate copolymer and a lactic acid polymer, and, where necessary, a polycaprolactone or a high-molecular aliphatic polyester. The card base has a single-layer structure, or a sandwich structure further having overlay layers comprising a composition containing, as essential components, a lactic acid polymer and either or both of a polycaprolactone and a high-molecular alphatic polyester.

Abstract: The invention provides a marine fishery article of threads which is made of threads consisting essentially of polycaprolactone represented by the formula ##STR1## wherein n is 300 to 2,000.

Abstract: Disclosed is a method for modifying a medical material of lactic acid polymer, the method comprising heat-treating the material at a temperature which is not lower than 100.degree. C. and is lower than the melting point of the polymer for at least 10 minutes while continuously releasing the gas from the system.