Method for producing a substantially continuous, nonporous thermoplastic coating and articles constructed therefrom

Abstract

This invention relates to a non-contact coating method for producing a substantially continuous coating and articles constructed therefrom. This invention further relates to a non-contact slot coating method for producing a variety of coatings and laminations. This invention particularly relates to a method of coating a non-porous substrate including film, foil and paper with a molten thermoplastic composition which reduces streaking caused by particles such as impurities, fillers and superabsorbent polymers. This invention further relates to thermoplastic compositions useful in the present non-contact coating method.

1 . A method of making a laminate, said method comprising: 
 releasing a molten hot melt adhesive composition from a slot nozzle in the form of a substantially continuous non-porous film, said slot nozzle being free from contact with a substrate, said hot melt adhesive composition having a complex viscosity of less than 500 poise at 1000 radians/second and less than 1000 poise at 1 radian/second at 177° C.;    disposing the substantially continuous non-porous film between a nip formed by a first roller and a second roller;    contacting a first nonporous substrate with the substantially continuous non-porous film;    contacting a second substrate with the substantially continuous non-porous film; and    nipping said first substrate, said substantially continuous non-porous film and said second substrate to form a laminate that is free of entrapped air.    
     
     
         2 . The method of  claim 1 , wherein said disposing, said contacting, and said nipping occur substantially simultaneously.  
     
     
         3 . The method of  claim 1 , wherein at least one of said first substrate and said second substrate comprises a polymer film.  
     
     
         4 . The method of  claim 1 , wherein at least one of said first substrate and said second substrate comprises a metal foil.  
     
     
         5 . The method of  claim 1 , wherein at least one of said first substrate and said second substrate comprises a metallized polymer film.  
     
     
         6 . The method of  claim 1 , wherein said first substrate and said second substrate comprise a polymer film.  
     
     
         7 . The method of  claim 1 , wherein said first substrate and said second substrate comprise a metal foil.  
     
     
         8 . The method of  claim 1 , wherein said first substrate comprises a polymer film and said second substrate comprise a metallized polymer film.  
     
     
         9 . The method of  claim 1 , wherein said first substrate comprises a plane film or embossed film.  
     
     
         10 . The method of  claim 1 , wherein said first substrate comprises a polymer film selected from the group consisting of oriented polypropylene, polyethylene, polyesters, polyacetate, nylon, cellulose acetate, and combinations thereof.  
     
     
         11 . The method of  claim 1 , wherein said substantially continuous nonporous film has a coating weight of less than 10 g/m 2 .  
     
     
         12 . The method of  claim 1 , wherein said hot melt adhesive composition comprises thermoplastic polymer, tackifying resin, and no greater than 40% by weight plasticizer.  
     
     
         13 . A method of making a laminate comprising: 
 releasing a hot melt adhesive composition that has been thermally made flowable from a coating device in the form of a substantially continuous nonporous film, said coating device being free from contact with a substrate or a roller,    contacting a release coated roller with said substantially continuous nonporous film;    contacting said substantially continuous nonporous film with a first nonporous substrate; and    nipping said substantially continuous nonporous film and said first substrate between a first roller and a second roller,    said substantially continuous nonporous film forming a coating on said first substrate, said coating having a coating weight less than 20 g/m 2 .    
     
     
         14 . The method of  claim 13 , wherein said first roller is said release coated roller.  
     
     
         15 . The method of  claim 13 , wherein contacting said substantially continuous nonporous film with a first substrate and nipping said substantially continuous nonporous film and said first substrate between a first roller and a second roller occur substantially simultaneously.  
     
     
         16 . The method of  claim 13  further comprising contacting said substantially continuous nonporous film with a second substrate.  
     
     
         17 . The method of  claim 16  further comprising nipping said second substrate, said substantially continuous nonporous film and said second substrate between a third roller and a fourth roller.  
     
     
         18 . The method of  claim 17 , wherein contacting said substantially continuous nonporous film with said second substrate, and nipping said second substrate, said substantially continuous nonporous film, said first substrate between a third roller and a fourth roller occur substantially simultaneously.  
     
     
         19 . The method of  claim 16 , wherein said first substrate and said second substrate are of a different composition.  
     
     
         20 . The method of  claim 16 , wherein said first substrate and said second substrate are of the same composition.  
     
     
         21 . The method of  claim 16 , wherein said first substrate comprises metal foil, metallized polymer film or polymer film, and said second substrate comprises metal foil, metallized polymer film or polymer film.  
     
     
         22 . The method of  claim 13 , wherein said hot melt adhesive composition has a complex viscosity of less than 500 poise at 1000 radians/second and less than 1000 poise at 1 radian/second at 177° C.;  
     
     
         23 . The method of  claim 13 , wherein said hot melt adhesive composition comprises thermoplastic polymer, tackifying resin, and no greater than 40% by weight plasticizer.  
     
     
         24 . The method of  claim 13 , wherein said coating device comprises a slot nozzle.  
     
     
         25 . The method of  claim 13 , wherein said first substrate comprises plane or embossed film.  
     
     
         26 . The method of  claim 13 , wherein the first substrate comprises oriented polypropylene, polyethylene, polyesters, polyacetate, nylon, cellulose acetate and combinations thereof.  
     
     
         27 . The method of  claim 16 , wherein said second substrate is selected from the group consisting of paper and cardboard.  
     
     
         28 . The method of  claim 13 , wherein said continuous film has a coating weight of less than 10 g/m 2 .  
     
     
         29 . The method of  claim 13  wherein at least one of said first roller and said second roller is heated.