| 摘要 |
PURPOSE:To obtain a thermoplastic resin container free of torsion, warping, etc., by a method in which in the manufacture of a video tape cassette, for example, a developed plate of thermoplastic resin is molded, a printing is applied to the developed plate in such a way so to forcily fix the printing ink, and the developed plate is made into a box form. CONSTITUTION:A developed plate 2 of a thermoplastic resin (e.g., polypropylene resin, etc.) is molded by extrusion into a long form by a T-die, and a fixed thickness of the thermoplastic resin flat plate so obtained is notched to form notches 13-16. Ruled lines 12 are then formed on the flat plate by compression molding or cutting process. A print is applied to the plate 2, the printing ink is forcibly fixed within 30min, and the plate 2 is bent at the ruled lines 12 into a box form. Since the average thickness of the ruled line is 5% or more thinner than the developed plate, or 0.15-1.5mm., the ruled line itself can keep its necessary rigidity and also the deformation to be encountered when the printing ink is forcibly fixed can be reduced. |
