HEATING MOLDING METHOD OF POLY(METHYL METHACRYLATE) SHEET AND WORKED PRODUCT OBTAINED THROUGH SAID METHOD

摘要

PURPOSE: To keep the outer appearance and color of a sheet even after being thermoformed and, even after a long term storage, the sheet can easily be separated by a method wherein a protective film made of an ethylene polymer having specified density and melt index is used. CONSTITUTION: In the thermoforming method of a poly-sheet having the reduced viscosity of 1.5 or more, as an ethylene polymer protective film, the ethylene polymer having the density of below 0.935 and the melt index of 1.5 g/10 min or less is employed. When the protective film is employed as it is or with no coating of an acrylic adhesive, the ethylene polymer film having the density of below 0.935 and about 0.910 or more is selected. Though the ethylene polymer film can be pasted to a poly(methyl methacrylate) (henceforth expressed as PMMA) sheet by means of various methods, until the time when a pressure is applied to a laminate of a sheet/film, either the ethylene polymer film or the PMMA sheet is heated so as to soften the ethylene polymer for its favorable bonding with the sheet.