| 摘要 |
PROBLEM TO BE SOLVED: To restrain occurrence of clearance between cylindrical walls in a gas injection valve for airtight bags, fitted in an airtight bag used as a cushioning body or cargo shift preventive material when easy-to-break or easy-to-be-damaged commodities are packaged and transported, and thus enhance the airtightness thereof, and to facilitate operation of discharging gas from the airtight bag. SOLUTION: The gas injection valve 2 is constituted of a plurality of layers of flexible polymeric films 4, 4', 5, 5', and mounted on a part of the airtight bag 1. One end of the gas injection valve 2 is positioned outside the airtight bag 1 while the other end is positioned inside the airtight bag 1. The gas injection valve 2 is so formed that a double-layer portion S1 constituted of the outside polymeric films 4, 4' and inside polymeric films 5, 5' is placed in communication with a uni-layer portion S2 constituted only of the inside polymeric films 5, 5' at the tip end side, both of their side rim portions 10, 10' being integrally thermally bonded for their whole layers, thereby being made into a flat dual cylindrical form. The double-layer portion S1 of the gas injection valve 2 is positioned outside the airtight bag 1 while the uni-layer portion S2 is positioned inside. At the central portion of the tip end portion 8 of the uni-layer portion S2 positioned inside the airtight bag 1, a micro joint portion 9 is partially provided. COPYRIGHT: (C)2005,JPO&NCIPI
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