| 摘要 |
PURPOSE: To absorb expansion and shrinkage in an airtight chamber generated by the variation of temperature by the existence of a foamed body by overlapping three sheets consisting of two synthetic resin films of high airtightness and a non-stretchable sheet, interposing the foamed body between the synthetic resin film and sheets and heat welding peripheral edges. CONSTITUTION: Synthetic films 1, 1 and a sheet 2 are overlapped and a foamed body is interposed between the films 1 and the sheet 2, and then the peripheral edges of films 1, 1 and the sheet 2 are heat welded, and an airtight chamber 5 and an air chamber 6 with a built-in foamed body 3 are formed by a peripheral edge sheet 4. A plug 7 for injecting and exhausting air to the airtight chamber 5 is set on the peripheral edge 4. The material quality of the sheet 2 is non-stretchable by expansion pressure and heat weldable with the synthetic resin film in use, and a plurality of venting holes are formed on its surface. The increase and decrease of air volume generated by the variation of temperature can be absorbed and replenished to prevent the breakage of a stored article generated by the breakage or contraction by the foamed body 3 and also the breakage of a stored article generated by the breakage or shrinkage of a case caused by expansion can be prevented. |
