Method for preparing air channel-equipped film for use in vacuum package

Abstract

Disclosed is a method for preparing an air channel-equipped film for use in vacuum packages, which comprises the step of providing a gas-impermeable base, along with a melt-extruded heat-sealable resin, to a laminating unit consisting of a laminating roll and a cooling roll, to form a heat-sealable resin layer on the gas-impermeable base, characterized in that the heat-sealable resin is molded and quenched in such a way that a plurality of protrusions, corresponding to a plurality of grooves formed in a predetermined pattern on the circumferential surface of the cooling roll, are formed on the molded heat-sealable resin layer, defining channels for the evacuation of air therebetween. The method is simple because of its ability to form air channels without the aid of additional embossing techniques, as well as being economically favorable owing to the employment of no embossing molds.

1 . A method for preparing an air channel-equipped film for use in vacuum package, comprising the step of feeding a gas-impermeable base, along with a melt-extruded heat-sealable resin, to a laminating unit consisting of a laminating roll and a cooling roll to form a heat-sealable resin layer on a gas-impermeable base layer, said heat-sealable resin layer being molded and cooled in such a way that a plurality of protrusions, corresponding to a plurality of grooves formed in a predetermined pattern on a circumferential surface of the cooling roll, are formed on the heat-sealable resin layer, defining channels for the evacuation of air therebetween.  
   
   
       2 . The method according to  claim 1 , wherein the gas-impermeable base layer is made of a material selected from the group consisting of polyamide, polyester, and ethylene vinyl alcohol (EVOH).  
   
   
       3 . The method according to  claim 1 , wherein the heat-sealable resin layer is made of polyethylene.  
   
   
       4 . The method according to  claim 1 , wherein the grooves of the cooling roll are formed in an uneven pattern on the circumferential surface of the cooling roll.  
   
   
       5 . The method according to  claim 1 , wherein the grooves of the cooling roll are formed in a wave pattern on the circumferential surface of the cooling roll.  
   
   
       6 . The method according to  claim 1 , wherein the grooves of the cooling roll are formed in a stripe pattern on the circumferential surface of the cooling roll.  
   
   
       7 . The method according to  claim 2 , wherein the gas-impermeable base layer consists of single layer, or two or more layers.  
   
   
       8 . A bag for use in vacuum packages, comprising a first sheet and a second sheet overlapping with each other, each of which is composed of a laminated film consisting of a gas-impermeable base layer as an outer layer and a heat-sealable resin layer as an inner layer, said first sheet and the second sheet being bonded to each other along lower, left, and right edges thereof so as to form a space for receiving a product to be vacuum packaged therein, wherein at least one of the first sheet and the second sheet is a film for use in vacuum packages produced according to the method of  claim 1.