A deoxidizer parcel has a sack-type parcel body and a deoxidizer contained in the parcel body. At least a part of the parcel body being made of a composite sheet which is composed of a gas-permeable sheet such as a sheet of paper or a non-woven cloth and a plastic film laminated on and bonded to the gas-permeable sheet. The plastic film has a multiplicity of minute pores formed by subjecting the plastic film already bonded to the gas-permeable sheet to an irradiation with a laser beam.Get more news about
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The present invention relates to a parcel of a deoxidizer and, more particularly, to a parcel which contains a deoxidizer for long preservation or package of goods such as foodstuffs, garments and drugs.
2. Description of the Related Art
In recent years, a method has been used widely for storing and preserving various goods such as foodstuffs, garments and drugs, by keeping such goods in a sealed system together with a deoxidizer which removes oxygen in the sealed system.
Usually, the deoxidizer in such a sealed system is contained in a small sack or parcel with gas-permeable wall. It is preferred that the material of the parcel enables the gas- or oxygen permeability to be adjusted as desired.
To comply with such a demand, various parcel materials have been proposed hitherto. For instance, Japanese Utility Model Post-Examination Publication No. 44-20879 discloses a laminated sheet material composed of a paper having a large gas-permeability and a polyethylene film having a multiplicity of tiny pores, the paper and the polyethylene film being heat-bonded together. On the other hand, Japanese Patent Post-Examination Publication No. 60-37791 discloses a laminated sheet material composed of two plastic films with tiny pores superposed on each other through the intermediary of a sheet of water-proof paper.
These known materials, which employ plastic films and paper sheets bonded together by heat and pressure, suffer from a common disadvantage in that the tiny pores in the plastic film are refilled or deformed by the heat and pressure applied during the bonding with the result that the gas-permeability of the sack fluctuates greatly. Another problem is that the laminated sheet materials exhibit only a small resistance to any force which acts to delaminate the plastic film and the paper sheet from each other.
Accordingly, an object of the present invention is to provide a deoxidizer parcel made of a laminated sheet material which experiences only a small fluctuation, if any, in the gas-permeability and which has an improved strength against any delaminating force.
To achieve this technical object, the present inventors made an intense study to reach a conclusion that a deoxidizer parcel, which enables an easy adjustment of gas-permeability and which has a large strength against delaminating force, can be obtained by using, as the sack material, a laminated sheet composed of a gas-permeable sheet and a plastic film bonded together, wherein, the plastic film is irradiated with a laser beam after the bonding so that only the plastic film is perforated.
Thus, according to the present invention, there is provided a deoxidizer parcel having a parcel body and a deoxidizer contained in the parcel body, at least a part of the parcel body being made of a composite sheet, the composite sheet comprising: a gas-permeable sheet; and a plastic film laminated on and bonded to the gas-permeable sheet and having a multiplicity of minute pores; the pores having been formed by subjecting the plastic film already bonded to the gas-permeable sheet to irradiation with a laser beam.
