| 摘要 |
<p>PURPOSE:To enhance resistance to gas permeability by using a multi-layer container constituted of at least five layers or more, constituting of polystyrene outer layers and inner layers and a high density polyethylene intermediate layer and constituting ethylene-vinyl acetate copolymer bonding layers between said layers. CONSTITUTION:As for resin constituting outer and inner layers of a multi-layer container, polystyrene of superior molding properties of the container, particularly of deep drawing properties and rigidity, is used. As for polystyrene, a styrene single polymer, a styrene and vinyl compound or a copolymer (Copolymerization ratio of vinyl compound or unsaturated carboxylic acid is 50wt.% or less.) composed of styrene and unsaturated carboxylic acid (for example, oleic acid, maleic acid or the like), or else, high-impact strength styrene copolymer is used, and particularly the high-impact strength styrene copolymer is preferred. As for resin composing an intermediate layer, high-density polyethylene of superior resistance to gas permeability is used, and its density should be 0.95g/cm<3> or more. As for resin composing the area between the outer layer and the intermediate layer or the area between the inner layer and the intermediate layer, an ethylene-vinyl acetate copolymer is used.</p> |
