Possesses water absortion power and moisture containment Characteristic the polystyrene type resin foaming sheet layered product

摘要

PROBLEM TO BE SOLVED: To provide a polystyrene resin expanded sheet laminate, which can absorb, and adsorb and retain steam or solidified water, and is suitable for a packaging container of perishable foods, lid material for heated foods or the like. SOLUTION: A polystyrene resin expanded sheet laminate is constituted by laminating non-expanded resin on one surface of a substrate made of polystyrene resin expanded sheet containing resin of water absorption properties. On the substrate surface opposite to the side laminated with the non-expanded resin, the ratio of 14kHz - vertical wave's propagation velocity in the extrusion direction and orthogonal direction to the extrusion direction on the surface layer (propagation velocity in the extrusion direction/propagation velocity in the orthogonal direction) is 0.8-0.9 or 1.1-1.2. And two or more cuts with the depth of 1/2-2/3 of the base thickness are provided on the base surface.