| 摘要 |
PROBLEM TO BE SOLVED: To provide a laminated foam sheet mainly made of a polyolefin material high in the gas barrier properties of foam, without collapse of foam even if stress is applied over a long period of time and deterioration in its cushioning capacity. SOLUTION: In a plastic foam sheet constituted by laminating a cap film made of a plastic material and having a large number of cap shaped bulges and a flat back film 2 made of a plastic material along the bottom surface of the cap film, each of the cap film and the back film is a laminated film wherein two or four layers (A, B) of the same kind or a different kind are laminated. This laminated film is produced by dividing the flow of a molten plastic material into left and right flows during a period when the molten plastic material reaches a T-die from an extruder and performing operation for supperposing the divided flows one upon another at least once.
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