| 摘要 |
PURPOSE:To minimize curling and to improve the peel strength between layers and folding tendency by a method in which corona discharging treatment is applied onto the surface of polysthylene resin film layer with a specified high density, and on said film, the flexible sheet layer with a specified Young's modulus, is laminated through an adhesive, and then photoinsulating material is incorporated in any layer thereof. CONSTITUTION:A multilayer coextruded film layer 4a having the film layer 2a of corona discharge-treated high density polyethylene (HDPE) resin having 0.1-5 g/10min. melt index and 0.941 g/cm<3> or more of density and the film layer 3a of linear chain low density polyethylene (L-LDPE) resin, is laminated on the flexible sheet layer 1 with 60 kg/mm<2> or more longitudinal Young's modulus through an adhesive layer 5, while corona discharge treatment is applied onto the surface of HDPE resin film 2a. A light screening material such as carbon black is incorporated in any layer thereof. As the flexible sheet 1, a biaxially oriented thermoplastic resin film with 6-50mum thickness or aluminium vacuum deposited biaxially oriented thermoplastic resin film is preferable. The adhesive layer 5 contains 20 wt.% or more of L-LDPE resin being copolymer resin made of ethylene and alpha-olefin with 4-8 carbon atoms.
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