Paper-plastic laminate sheeting

Abstract

A paper-plastic laminate sheeting capable of being converted by conventional equipment into envelopes, grocery bags and other dilatable container products that initially are in a flat state and are normally made of paper. The sheeting is composed of a paper facing sheet cold-laminated by means of a water-based adhesive to a reinforcing film of synthetic plastic material, such as polypropylene. The film is oriented to impart exceptional tear and burst strength characteristics to the resultant waterproof product. The product, whose exterior surface is formed by the paper facing sheet, is readily printable. For some applications, a second paper facing sheet is cold-laminated to the other side of the film to produce a three-ply laminate sheeting whose exposed surfaces are readily printable and can accept conventional adhesives.

1 . A paper-plastic laminate comprising at least one paper sheet, a reinforcing film of a synthetic oriented polymer that has at least one surface treated to increase its dynes and make it receptive to adhesives, wherein the film is laminated to at least one of the paper sheets by an adhesive and in a manner that does not affect the orientation of the polymer film, with the paper sheet contacting the treated surface of the film that carries the adhesive so that water present in the adhesive is absorbed by the paper sheet to effect lamination of the film to the paper.  
     
     
         2 . The laminate sheeting of  claim 1  wherein the film has undergone molecular orientation to increase its strength prior to lamination, and the surface of the film is treated by ionization using corona discharge.  
     
     
         3 . The laminate sheeting of  claim 1  wherein the film is biaxially oriented.  
     
     
         4 . The laminate sheeting of  claim 1  wherein the film is polypropylene, polyethylene, or polyester.  
     
     
         5 . The laminate sheeting of  claim 1  wherein the water-based adhesive is a polyacrylate or vinyl acetate ethylene copolymer.  
     
     
         6 . The laminate sheeting of  claim 1  wherein the paper facing sheet is formed of Kraft paper.  
     
     
         7 . A paper-plastic-paper laminate comprising first and second paper outer facing sheets each having first and second surfaces, and a reinforcing film of a synthetic oriented polymer film having first and second surfaces, with each surface of the film treated to increase its dynes and its affinity to adhesives, wherein the film is laminated to the first surface of each facing sheet by an adhesive, with the first surface of each paper sheet contacting a treated surface of the film that carries the adhesive so that water present in the adhesive is absorbed by the paper sheets to effect lamination of the film to the paper sheets.  
     
     
         8 . The laminate sheeting of  claim 7  wherein the film has undergone molecular orientation to increase its strength prior to lamination, and the surface of the film is treated by ionization using corona discharge.  
     
     
         9 . The laminate sheeting of  claim 7  wherein the film is biaxially oriented.  
     
     
         10 . The laminate sheeting of  claim 7  wherein the film is polypropylene, polyethylene, or polyester.  
     
     
         11 . The laminate sheeting of  claim 7  wherein the water-based adhesive is a polyacrylate or vinyl acetate ethylene copolymer.  
     
     
         12 . The laminate sheeting of  claim 7  wherein the paper facing sheet is formed of Kraft paper.  
     
     
         13 . A method of making a flexible paper-plastic laminate which comprises: providing a supply of a first paper sheet having first and second surfaces; providing a supply of a reinforcing film of a synthetic oriented polymer material having first and second surfaces; treating the first surface of the film to increase its dynes and its affinity to adhesives; applying a water-based adhesive to the treated first surface of the film; and laminating the adhesive bearing first film surface to the first surface of the paper sheet in a manner Such that the orientation of the polymer film is not detrimentally affected and the water of the adhesive is absorbed by the paper sheet to effect lamination thereof and form a paper-plastic laminate.  
     
     
         14 . The method of  claim 13 , which further comprises: providing a supply of a second paper sheet having first and second surfaces; treating the second surface of the film to increase its dynes and its affinity to adhesives; applying a water-based adhesive to the treated second surface of the film; and laminating the adhesive bearing second film surface to the first surface of the second paper sheet such that the water of the adhesive is absorbed by the second paper sheet to effect lamination thereof and form a non-curling, three-ply laminate sheeting product that has an inner plastic film and outer paper surfaces.  
     
     
         15 . The method of  claim 14 , wherein the film has undergone molecular orientation to increase its strength prior to lamination, and the treated first and second surfaces are achieved by ionization using corona discharge.  
     
     
         16 . The method of  claim 15 , wherein the film is biaxially oriented.  
     
     
         17 . The method of  claim 16 , wherein the orientation of the film is unchanged after cold laminating.  
     
     
         18 . The method of  claim 13 , wherein the film is polypropylene, polyethylene or polyester.  
     
     
         19 . The method of  claim 13 , wherein the water-based adhesive comprises a polyacrylate or vinyl acetate ethylene copolymer and the paper facing sheet is formed of Kraft paper, white paper or coated paper.  
     
     
         20 . The method of  claim 14 , wherein each water-based adhesive comprises a polyacrylate or vinyl acetate ethylene copolymer and the paper facing sheet is formed of Kraft paper, white paper or coated paper.  
     
     
         21 . The method of  claim 13 , wherein the laminate sheeting is produced at a speed of 150 to 500 feet per minute or greater.