| abstract |
(57) [Summary] (Modifications) [PROBLEMS] The present invention has excellent water vapor permeability resistance, easy piercing property, printability, and does not generate adhesiveness when heat-sealed to a base material at high temperature. Excellent sealing strength, Further, the present invention provides a cover material sheet containing polystyrene having a substantially syndiotactic structure, in which a used cover material can be incinerated under the same conditions as the bottom material. The present invention comprises, as an essential component, a composition in which a surface layer (A) layer comprises a specific amount of a styrene polymer having a syndiotactic structure and a polyolefin polymer or amorphous polystyrene. A) a layer composed solely of a layer or a composition comprising the above (A) and an amorphous polystyrene-based polymer and / or a copolymer of an α-olefin and a cyclic polyolefin as an essential component; Wherein the layer (A) is heat-treated to crystallize a styrenic polymer having a substantially syndiotactic structure. |