Patent ID: 7544414

Claim:
An oriented syndiotactic polystyrene-based film, comprising a film consisting of a styrene-based polymer having a syndiotactic structure, and a laminated adhesiveness-improving layer on at least one side of said film, wherein said layer comprises one or more of the following resins (A)-(H): (A) a water-dispersible polymer made by copolymerizing a monomer having an aromatic ring on its side chain with an acrylic monomer; (B) a water-dispersible copolymerized polyester having a glass transition temperature of 30° C. or less, and/or a water-dispersible copolymerized polyester satisfying the following (1): (1) a ratio of B/(A+B) is 0.07 to 0.25, wherein A and B are the integrated values at chemical shifts of 1.0 ppm to 6.0 ppm and 7.0 ppm to 9.0 ppm, respectively, in 1 H NMR; (C) a water-soluble and/or a water-dispersible polyurethane resin; (D) a water-soluble and/or a water-dispersible polyamide resin; (E) a water-dispersible polyacrylonitrile resin; (F) a water-dispersible ethylene-vinyl ester copolymer resin; (G) a water-dispersible modified polyolefinic resin; and (H) a copolymer resin having an isobutylene unit, a maleic acid unit, and a n-butyl acrylate unit; wherein said adhesiveness-improving layer comprises a polymer comprising a polystyrene sulfonate salt as a major component.