Sekisui Kaseihin Kogyo Kabushiki Kaisha

Bon Machida

Masahiro Tsubone

Nobuyuki Komatsuzaki

A polystyrene foamed sheet suitable for thermoforming and containers such as cups or trays formed therefrom, the foamed sheet comprising a polystyrene resin as the base resin which contains a specific quantity of each a rubber component and a filler, having specific bulk density, thickness, stretch ratio and residual gas quantity, and said sheet being preferably laminated with a film.

Polystyrene foamed sheet suitable for forming

A sleeve and method of making the same comprising a laminate sheet having a more highly shrinkable foamed film and a lesser shrinkable non-foamed film, the ends of the laminate being bonded together so that the foamed film faces the interior of the sleeve. The foamed film has a thicker surface layer on its side opposite that laminated to the non-foamed layer, which therefore faces the interior of the sleeve. The flow direction shrinkage rate of the laminated sheet, which is 60% or less, is greater than the widthwise shrinkage rate of the laminated film. The widthwise shrinkage rate is 10% or less.

Sheet for forming sleeve and process for producing the same

This invention relates to a process for producing economically shaped article of polystyrene foam with a small wall thickness and sufficient strength by a continuous simple operation including a short forming cycle in which the sheet of polystyrene foam having a bulk density of 0.15 to 0.7 g/cm.sup.3, a thickness of 0.3 to 1.0 mm, 5 to 20 cell membranes widthwise of the sheet and a draw ratio of up to 1.25 and containing 0.03 to 0.3 mole/kg of the residual gas of the blowing agent is formed by an extruder and utilized to produce the shaped article.

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Koga, Japan

Bon Machida