Sheet for forming sleeve and process for producing the same
AssigneeSekisui Kaseihin Kogyo Kabushiki Kaisha
InventorsMasahiro Tsubone, Bon Machida
Life of this patent
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Abstract
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.
Claims13
A sleeve comprising a laminated sheet having a more highly shrinkable foamed film and a lesser shrinkable non-foamed film, said films comprising polystyrene containing more than 50% by weight of styrene residues, said non-foamed film also comprising rubber in an amount not more than 30% by weight;
- flow-direction ends of said laminated sheet being bonded together so that a thicker skin surface of said foamed film faces the interior of said sleeve;
- said laminated sheet having a flow-direction shrinkage rate of 60% or less and a widthwise shrinkage rate of 10% or less, said flow-direction shrinkage rate being greater than said widthwise shrinkage rate.
A process for producing a sheet for forming a sleeve which comprises:
- forming a laminated sheet by concurrently extruding a foamed polystyrene film and a non-foamed polystyrene film;
- cooling said foamed film more quickly than said non-foamed film, so that said foamed film has a higher shrinkage rate than said non-foamed film, and said foamed film has a surface skin layer thickner on its side opposite that laminated to said non-foamed film;
- stretching said laminated sheet at different rates relative to the flow and widthwise directions of said laminated sheet, so that the resulting flow-direction shrinking rate is greater than the widthwise shrinking rate and is 60% or less and said widthwise shrinkage rate is 10% or less.
A laminate comprising a sheet having a more highly shrinkable foamed film and a lesser shrinkable non-foamed film, said films comprising polystyrene, said foamed film having a skin surface thicker on its side opposite that laminated to said non-foamed film;
- said laminated sheet having a flow-direction shrinkage rate of 60% or less and a widthwise shrinkage rate of 10% or less, said flow-direction shrinkage rate being greater than said widthwise shrinkage rate.
Dependencies are inferred from the claim text.