Food packaging film

Abstract

In the present invention, there is provided a food packaging film which is excellent in workability, processability, productivity, gas barrier properties, low-temperature heat sealing properties, safety and mechanical strengths, which can be used as an alternative film to generally used cellophane/wax films, and can be suitably used as a packaging film for melting cheese. The food packaging film according to the present invention comprises at least five layers of a heat seal layer/an adhesive layer/a gas barrier layer/an adhesive layer/a heat seal layer, which heat seal layer comprises an olefin-based resin and melts at not lower than 60° C. and lower than 90° C.

1 .- 10 . (canceled) 
     
     
         11 . A method of making an air-tight food packaging comprising:
 (a) forming a container of the food packaging film comprising at least five layers of a heat seal layer/an adhesive layer/a gas barrier layer/an adhesive layer/a heat seal layer, which heat seal layer comprises an olefin-based resin and melts at not lower than 60° C. and lower than 90° C.,   in which the heat seal layer comprises 40 to 100% by weight of polyethylene obtained by polymerization in the presence of a metallocene catalyst, or the heat seal layer comprises 40 to 95% by weight of the olefin-based resin and 5 to 40% by weight of an anti-blocking agent and/or a lubricant,   (b) feeding a melted food having a temperature of not lower than 60° C. and less than 90° C. into the container,   (c) folding the food packaging film, and   (d) heat-sealing at least part of a surface of one side and the surface of an opposite side of the folded and overlapped food packaging film by heat of the fed melted food having a temperature of not lower than 60° C. and less than 90° C.   
     
     
         12 . The method according to  claim 11 , wherein the heat seal layer of the food packaging film comprises 40 to 75% by weight of polyethylene having a density of less than 0.905 g/cm 3  and obtained by polymerization in the presence of a metallocene catalyst, and 25 to 60% by weight of low-density polyethylene having a density of not less than 0.905 g/cm 3 . 
     
     
         13 . The method according to  claim 11 , wherein the polyethylene of the food packaging film is obtained by polymerization in the presence of a metallocene catalyst has a melting point of 60 to 70° C. 
     
     
         14 . The method according to  claim 11 , wherein the gas barrier layer of the food packaging film comprises at least one polymer selected from the group consisting of polyamide, ethylene-vinylalcohol copolymer, polyethylene terephthalate, polyethylene naphthalate and polycarbonate. 
     
     
         15 . The method according to  claim 11 , wherein the adhesive layer of the food packaging film comprises an unsaturated carboxylic acid-modified polyolefin. 
     
     
         16 . The method according to  claim 11 , wherein the food is melted cheese. 
     
     
         17 . The method according to  claim 11 , wherein the food packaging film is colored. 
     
     
         18 . A method of packaging a product comprising the steps of:
 (a) forming a container for a food product from a food packaging film comprising at least five layers of a heat seal layer/an adhesive layer/a gas barrier layer/an adhesive layer/a heat seal layer, which heat seal layer comprises an olefin-based resin and melts at not lower than 60° C. and lower than 90° C.,   in which the heat seal layer comprises 40 to 100% by weight of polyethylene obtained by polymerization in the presence of a metallocene catalyst, or the heat seal layer comprises 40 to 95% by weight of the olefin-based resin and 5 to 40% by weight of an anti-blocking agent and/or a lubricant,   (b) filing the container formed in step (a) with a food product having a temperature of not lower than 60° C. and lower than 90° C.,   thereby causing the heat seal layer or layers in contact with each other to fusion seal from the heat of the food product thereby heat sealing the food product in an air-tight container.