| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a card material for allowing practical manufacturing of the card material by giving strength and heat resistance to a polylactic acid sheet obtained by extrusion so that it can endure manufacturing of cards and by allowing post-processing such as printing. SOLUTION: The method for manufacturing card base material includes: a sheet forming step wherein a resin principally consisting of polylactic acid is extruded into a sheet at a temperature higher than a melting point of the resin and then cooled to be formed into a flat sheet; a heating step wherein the flat sheet is heated and maintained at a temperature higher than a crystallization temperature of the resin and lower than the melting point while keeping the flat shape of the sheet; and a cooling step wherein subsequently the flat sheet is cooled and maintained at a temperature lower than the crystallization temperature of the resin while keeping the flat shape of the sheet. COPYRIGHT: (C)2011,JPO&INPIT |
