PURPOSE: To prevent a stamp forming material from absorbing moisture, and prevent hydrolizing due to water content at the time of heating of a thermoplastic resin from happening by a method wherein a stamp forming material of which periphery is covered by a protective film is vacuum-packaged in a packaging bag which is made of a moistureproof film with a specific steam permeation constant.
CONSTITUTION: A stamp forming material of which periphery is covered by a protective film is vacuum-packaged in a packaging bag which is made of a moistureproof film of which steam permeation constant is 0.1g.20μ/m2.day/atm or lower for the title packaged body. For the protective film, normally a flexible film with a thickness of 20μ or higher and fracture ductility of 10% or higher, e.g. a film made of vinyl chloride with a thickness of 100-200μ is suitable. For the moistureproof film, e.g. a film for which on a biaxial orientation film such as polyethylene or vinyl chloride or nonorientation film, aluminum foil is laminated is suitable. By using the stamp forming material packaged body, water content of a stamp forming material can be kept at 500ppm or lower for a long period of time, and forms which are obtained by stamp forming this type of stamp forming material do not receive heat deterioration and have an excellent mechanical performance.
FUJII KIYONOBU
HORI NAONOBU
YAMANA YOSHIHIRO
ONISHI ISAO
