Vacuum packaging bags and multi-layer vacuum packaging film

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 - 8 . (canceled)  
   
   
       9 . A multi-layer film suitable for use in forming a vacuum packaging bag, said multi-layer film comprising: 
 a patterned layer formed of a first material including a heat-sealable resin, said patterned layer having a plurality of grooves which operate to form channels suitable for evacuation of gas when said multi-layer film is used to form said vacuum packaging bag, said patterned layer formed through melt extrusion of said first material onto a patterned roller, whereby said patterned layer has a substantially uniform distribution of material substantially lacking deformities present in an embossed film having a similar pattern formed by an embossing process;    a base layer coupled to said patterned layer, said base layer including at least a gas impermeable layer,    wherein said patterned layer serves as a heat-sealable inner layer in a typical vacuum packaging application, and said gas impermeable layer serves to maintain a vacuum in said typical vacuum packaging application.    
   
   
       10 . A multi-layer film as recited in  claim 9 , wherein said heat-sealable resin is a polyethylene resin.  
   
   
       11 . A multi-layer film as recited in  claim 9 , wherein said pattern is a wave pattern.  
   
   
       12 . A multi-layer film as recited in  claim 9 , wherein said pattern is a criss-cross pattern.  
   
   
       13 . A multi-layer film as recited in  claim 9  wherein said pattern is a straight-line pattern.  
   
   
       14 . A multi-layer film as recited in  claim 9 , wherein said pattern is an uneven pattern.  
   
   
       15 . A multi-layer film as recited in  claim 9 , wherein said base layer is laminated onto said patterned layer.  
   
   
       16 . A multi-layer film as recited in  claim 9 , wherein said base layer includes at least one structural layer for adding strength to the multi-layer film.  
   
   
       17 . A multi-layer film comprising a substantially flat base layer including a gas impermeable layer and a patterned layer including a heat-sealable resin, said patterned layer having a first side and a second side, said second side of said patterned layer coupled to said substantially flat base layer, said multi-layer film characterized in that: 
 said multi-layer film is for use as vacuum packaging bag material;    said second side of said patterned layer is formed substantially flat without a pattern; and    said first side of said patterned layer includes a pattern that has a plurality of protrusions formed in said first side such that space between said plurality of protrusions defines air channels useful for evacuation in vacuum packaging applications.    
   
   
       18 . A multi-layer film as recited in  claim 17 , wherein said pattern formed by said plurality of protrusions is a wave pattern.  
   
   
       19 . A multi-layer film as recited in  claim 17 , wherein said pattern formed by said plurality of protrusions is a criss-cross pattern.  
   
   
       20 . A multi-layer film as recited in  claim 17 , wherein said pattern formed by said plurality of protrusions is a straight-line pattern.  
   
   
       21 . A heat-sealable vacuum packaging bag for holding food or other product, said heat-sealable vacuum packaging bag comprising: 
 a first sheet formed of a multi-layer plastic film, said multi-layer plastic film including: 
 a patterned inner layer formed of a heat-sealable material, said patterned inner layer having a plurality of grooves which operate to form channels suitable for evacuation of gas when said multi-layer film is used to form said vacuum packaging bag, said patterned inner layer formed through heat extrusion of said heat-sealable material onto a patterned roll, whereby said inner layer has a substantially uniform distribution of material substantially lacking deformities normally present in an embossed film having a pattern formed by an embossing process; and  
 an outer layer laminated onto said patterned inner layer, said outer layer including a gas impermeable material;  
   a second sheet having a footprint substantially similar to said first sheet; and    said first and second sheets arranged with said patterned inner layer of said first sheet facing said second sheet, said first and second sheets heat-sealed on opposing lateral sides and at an end side,    whereby said first and second sheet form said vacuum packaging bag having an opening for insertion of food or other product, said vacuum packaging bag heat-sealable at said opening for insertion of food.    
   
   
       22 . A heat-sealable vacuum packaging bag as recited in  claim 21  characterized in that: 
 said outer layer is substantially flat;    said patterned inner layer has a first side and a second side;    said second side is substantially flat and coupled to said outer layer;    said first side has a plurality of protrusions formed in said first side such that space between said plurality of protrusions defines said plurality of grooves useful for evacuation in vacuum packaging applications; and    said first side is facing said second sheet.    
   
   
       23 . A heat-sealable vacuum packaging bag for holding food or other product, said heat-sealable vacuum packaging bag comprising: 
 a first sheet formed of a multi-layer plastic film, said multi-layer plastic film including: 
 a patterned inner layer including a sealable resin, said patterned inner layer having a plurality of grooves which operate to form channels suitable for evacuation of gas when said multi-layer film is used to form said vacuum packaging bag, said inner layer formed through heat extrusion of said first material onto a patterned cold roll, whereby said inner layer has a substantially uniform distribution of material substantially lacking deformities normally present in an embossed film having a pattern formed by an embossing process; and  
 an outer layer laminated onto said patterned inner layer, said outer layer including a gas impermeable material;  
   a second sheet including a gas impermeable material, said second sheet having an unpatterned inner layer made of a sealable resin; and    said first and second sheets arranged with respective inner layers facing one another, said first and second sheets sealed on opposing lateral sides and at an end side,    whereby said first and second sheet form said vacuum packaging bag having an opening for insertion of food or other product, said vacuum packaging bag heat-sealable at said opening for insertion of food.    
   
   
       24 . A vacuum packaging bag comprising: 
 a first sheet having a first patterned side and a second substantially flat side, said first sheet manufactured by a process including: 
 providing a gas impermeable base layer;  
 melt-extruding a heat-sealable resin onto said gas impermeable base layer thereby forming a heat-sealable layer coupled to said gas impermeable base layer;  
 forming said first patterned side by forming a pattern into an exposed side of said heat-sealable layer before said melt-extruded heat-sealable resin significantly solidifies;  
   a second sheet having a footprint substantially similar to said first sheet; and    said first and second sheets arranged with said patterned inner layer of said first sheet facing said second sheet, said first and second sheets heat-sealed on opposing lateral sides and at an end side,    whereby said first and second sheet form said vacuum packaging bag having an opening for insertion of food or other product, said vacuum packaging bag heat-sealable at said opening for insertion of food.    
   
   
       25 . A vacuum packaging bag as recited in  claim 24 , wherein said first sheet manufactured by said process is further characterized in that providing said gas impermeable layer includes feeding said gas impermeable layer into a laminating unit, said laminating unit including a laminating roll and a patterned roll,  
   
   
       26 . A vacuum packaging packaging bag as recited in  claim 25 , wherein said first sheet manufactured by said process is further characterized in that forming said first patterned side of said heat-sealable layer is accomplished by cooling and molding the melt-extruded heat-sealable resin between said patterned roll and said gas impermeable base layer, wherein said gas impermeable base layer is pressure applied to said heat-sealable layer via said laminating roll.  
   
   
       27 . A vacuum packaging bag as recited in  claim 25 , wherein said first sheet manufactured by said process is further characterized in that said process further includes controlling a temperature of said patterned roll.  
   
   
       28 . A vacuum packaging bag as recited in  claim 27 , wherein said patterned roll is cooled to a temperature between about −15 C and −10 C.  
   
   
       29 . A vacuum packaging bag comprising a first sheet and a second sheet, said first and second sheets arranged with inner heat-sealable layers facing one another, said first and second sheets heat sealed on opposing lateral sides and on an end side, whereby said first and second sheet form said vacuum packaging bag having an opening for insertion of food or other product, said vacuum packaging bag heat-sealable at said opening, said first sheet having a gas impermeable layer and a patterned heat-sealable layer, said vacuum packaging bag characterized in that: 
 said patterned heat-sealable layer has a first side that is formed substantially flat;    said first side of said heat-sealable layer is coupled to said gas impermeable layer of said first sheet; and    said patterned heat-sealable layer has a second side including a pattern that has a plurality of protrusions formed in said second side such that space between said plurality of protrusions defines air channels useful for evacuation in vacuum packaging applications.