| 摘要 |
The invention is a packaging bag for storing contents such as coffee beans and MISO (fermented soybean paste) that breathe and produce gas, which is capable of controlling oxidization of the contents during storage as well as venting the gas produced inside the bag. The body of the packaging bag includes a vent line formed on a part thereof and a synthetic resin film layer provided along the vent line; wherein the film layer contains particles made of a material that does not melt at the melting point of the film layer, and is drawn to be stretched. In the bag thus constructed, fine interstices are formed as ventholes adjacent to each particles in the thickness direction of the film layer so as to allow the gas inside the bag to be vented therethrough, when the bag expands with the gas produced by the contents through their breathing and the pressure inside the bag reaches a certain level.
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