DEGRADABLE INFORMATION RECORDING CARD

摘要

PURPOSE:To obtain a degradable information recording card having such strength as to cause no trouble at the time of ordinary use. CONSTITUTION:A substrate for a degradable information recording card is formed with a sheet of a polylactic acid polymer. The degree DELTAP of surface orientation of this substrate is >=3.0X10<-3> and the difference (DELTAHm-DELTAHc) between the quantity DELTAHm of heat of crystal melting at the time of heating the sheet and the quantity DELTAHc of heat of crystallization generated by crystallization during heating is >=20J/g. The objective degradable information recording card is produced using the substrate.