Reduced blocking metallized film

Abstract

Low temperature sealable metallized packaging films are found to have reduced blocking tendencies when an oxidized polyethylene wax is blended into a low temperature sealing composition including an ethylene-carboxylic acid copolymer. The films are useful for high-speed packaging applications requiring sealability at low temperatures. The films exhibit low blocking performance during unwinding of the film while maintaining positive low temperature sealability characteristics.

What is claimed is:  
     
         1 . A film comprising: 
 (a) a substrate having a first surface and a second surface;    (b) a metallic layer on the first surface; and    (c) a coating on the second surface comprised of at least one ethylene copolymer and at least one oxidized polyethylene wax.    
     
     
         2 . The film of  claim 1  wherein the coating is comprised of from about 5 Phr to about 25 Phr of the at least one oxidized polyethylene wax based upon 100 parts by weight of the ethylene copolymer.  
     
     
         3 . The film of  claim 2  wherein the metallic layer is uncoated and is comprised of a metal selected from the group consisting of aluminum, copper, silver, chromium, gold, and mixtures thereof.  
     
     
         4 . The film of  claim 3  wherein the at least one oxidized polyethylene wax has a drop point from about 85° C. to about 145° C.  
     
     
         5 . The film of  claim 4  wherein the substrate is comprised of a material selected from the group consisting of polypropylene, polyethylene, polybutene, polystyrene, polyvinyl chloride, polyesters, polyethylene terephtalate glycol, polyethylene naphthalate, and oriented nylon.  
     
     
         6 . The film of  claim 5  wherein the ethylene copolymer is selected from the group consisting of a copolymer of ethylene and a carboxylic acid and a copolymer of ethylene and an acrylic ester.  
     
     
         7 . The film of  claim 6  wherein the at least one ethylene copolymer has a melting point from about 65° C. to about 105° C.  
     
     
         8 . The film of  claim 7  wherein the at least one oxidized polyethylene wax has a drop point of from about 95° C. to about 140° C.  
     
     
         9 . The film of  claim 8  wherein the at least one ethylene copolymer is a copolymer of ethylene and carboxylic acid and the carboxylic acid is selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, crotonic acid, itaconic acid, citraconic acid, and mixtures thereof.  
     
     
         10 . The film of  claim 7  wherein the coating is comprised of from about 7 Phr to about 20 Phr of the at least one polyethylene wax based upon 100 parts by weight of the at least one ethylene copolymer.  
     
     
         11 . The film of  claim 9  wherein the carboxylic acid of the ethylene-carboxylic acid copolymer is selected form the group consisting of acrylic acid and methylacrylic acid, and mixtures thereof.  
     
     
         12 . The film of  claim 11  wherein the copolymer of ethylene and carboxylic acid comprises ions selected from the group consisting of sodium ions, potassium ions, lithium ions, calcium ions, zinc ions, and mixtures thereof.  
     
     
         13 . The film of  claim 10  wherein the at least one ethylene copolymer is a copolymer of ethylene and acrylic ester, wherein the acrylic ester is selected from the group consisting of methylacrylate, methylmethacrylate, butylacrylate, and mixtures thereof.  
     
     
         14 . The film of  claim 11  wherein the metallic layer is comprised of aluminum.  
     
     
         15 . The film of  claim 14  wherein the at least one oxidized polyethylene wax has a drop point of from about 98° C. to about 115° C.  
     
     
         16 . The film of  claim 15  wherein the substrate is comprised of a biaxially oriented polypropylene film.  
     
     
         17 . The film of  claim 16  wherein the substrate is a three layer film.  
     
     
         18 . The film of  claim 17  wherein the three layer film is comprised of a core layer comprised of biaxially oriented film and at least one skin layer.  
     
     
         19 . The film of  claim 18  wherein the skin layer of the film is comprised of a polymer selected from the group consisting of a copolymer of propylene and ethylene and a terpolymer of propylene, ethylene, and butylene.  
     
     
         20 . The film of  claim 17  wherein the film is opaque.  
     
     
         21 . The film of  claim 17  wherein at least one layer of the film is voided.  
     
     
         22 . The film of  claim 16  wherein the substrate is a five layer biaxially oriented film.  
     
     
         23 . The film of  claim 15  wherein the coating is comprised of from about 8 Phr to about 18 Phr of the at least one oxidized polyethylene wax based upon 100 parts by weight of the ethylene-carboxylic acid copolymer.  
     
     
         24 . The film of  claim 14  wherein the coating is comprised of about 10 Phr of the at least one oxidized polyethylene wax based upon 100 parts by weight of the ethylene-carboxylic acid copolymer and the at least one oxidized polyethylene wax has a drop point from about 98° C. to about 110° C.  
     
     
         25 . A package comprised of a film comprising: 
 (a) a substrate having a first surface and a second surface;    (b) a metallic layer on the first surface; and    (c) a coating on the second surface comprised of at least one ethylene copolymer and from about 5 Phr to about 25 Phr of a polyethylene wax based upon 100 parts by weight of the at least one ethylene copolymer.    
     
     
         26 . The packaged product of  claim 25  wherein the at least one ethylene copolymer is selected from the group consisting of a copolymer of ethylene and a carboxylic acid and a copolymer of ethylene and an acrylic ester.  
     
     
         27 . The packaged product of  claim 26  wherein the substrate is comprised of a material selected from the group consisting of polypropylene, polyethylene, polybutene, polystyrene, polyvinyl chloride, polyesters, polyethylene terephtalate glycol, polyethylene naphthalate, and oriented nylon and the polyethylene wax has a drop point of from about 95° C. to about 140° C.