MULTILAYER STRUCTURAL SHEET

PURPOSE:To obtain a low cost transparent sheet excellent in heat resistance and secondary processability by constituting the sheet of a core layer composed of thermoplastic polyester and a sheath layer composed of a copolymer of thermoplastic polyester and polyallylate baud specifying the wt. ratio of the core layer and the sheath layer. CONSTITUTION:A multilayer structural sheet consists of a core layer composed of thermoplastic polyester having 80% or more of an ethylene terephthalate unit and a sheath layer composed of a copolymer wherein the wt. ratio of thermoplastic polyester and polyallylate is within a range of (60:40)-(0:100) and the wt. ratio of the core layer and the sheath layer is set to (60:40)-(97:3). The thermoplastic polyester used as the core layer is obtained by copolymerizing 2-30 mol.% of isophthalic acid and 98-70 mol.% of terephthalic acid and has intrinsic viscosity of 0.65 or more. This multilayer structural sheet has an advantage capable of extremely reducing expensive polyallylate and is excellent in heat resistance and secondary processability and keeps transparency even in hot water for long time and, therefore, it can be widely utilized in a use for a food container.