| 摘要 |
PROBLEM TO BE SOLVED: To improve floating holding ability irrespective of its small size. SOLUTION: A balloon is composed of a laminated film of 1-10μm in thickness of a layer A, 5-30μm in thickness of a layer B, and (the thickness of the layer A)/(the thickness of the layer B)<=0.8 wherein a laminate containing respectively at least one layer of ethylene vinylester copolymer saponified material layer (the layer A) and a heat sealed layer consisting of polyolefin resin (the layer B) is costretched or corolled longitudinally and/or laterally to at least 1.5 times in area.
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