Process for calendering of polymeric vinyl films exhibiting high gloss and structural stability

Abstract

A method and apparatus for calendering polymeric vinyl films exhibiting high gloss and structural stability. Specifically, the invention presents a method and apparatus for calendering polyvinyl chloride film of such a nature. In accordance with the invention, a casting sheet is interposed within the calendering head wherein a blend of polyvinyl chloride resin is formed, in standard fashion, into a continuous film web. In accordance with one embodiment of the invention, the casting sheet, preferably of heat resistant polyester film, is introduced into a nip between existent processing rolls near the end of the processing head. Alternatively, a separate nip may be provided by the addition of a separate roll in juxtaposition to a final roll in the calendering head. In either instance, the casting sheet is forcefully applied to the polyvinyl chloride film prior to engagement with the embossing rolls of the manufacturing process.

What is claimed is:  
     
         1 . Apparatus for calendering polymeric vinyl films, comprising: 
 a calendering head for receiving a resin blend and forming a hot film therefrom;    an embossing station receiving said hot film; and    a casting sheet applicator introducing a casting sheet to said hot film prior to transfer to said embossing station.    
     
     
         2 . The apparatus for calendering polymeric vinyl films according to  claim 1 , wherein said calendering head comprises a plurality of rolls through which the resin blend and hot film passes, said casting sheet applicator applying said casting sheet to one of said calendering head rolls.  
     
     
         3 . The apparatus for calendering polymeric vinyl films according to  claim 2 , wherein said casting sheet is applied to said one of said calendering head rolls at a point prior to a calender nip.  
     
     
         4 . The apparatus for calendering polymeric vinyl films according to  claim 3 , wherein heat and pressure of said calender nip laminates said hot film to said casting sheet.  
     
     
         5 . The apparatus for calendering polymeric vinyl films according to  claim 4 , wherein said resin blend is a polyvinyl chloride resin blend and said casting sheet is a polyester film.  
     
     
         6 . The apparatus for calendering polymeric vinyl films according to  claim 1 , wherein said calendering head comprises a plurality of rolls through which the resin blend and hot film passes, said casting sheet applicator applying said casting sheet to said film as it exists said calendering head and prior to said embossing station.  
     
     
         7 . The apparatus for calendering polymeric vinyl films according to  claim 6 , wherein said casting sheet applicator comprises a roll of casting sheet and a nip roll, said nip roll effecting a pressure application of said casting sheet to said hot film.  
     
     
         8 . The apparatus for calendering polymeric vinyl films according to  claim 7 , wherein said cast sheet is a polyester film.  
     
     
         9 . A process for calendering polymeric vinyl films, comprising: 
 introducing a resin blend into a calendering head and forming a hot film therefrom;    applying a casting sheet to said hot film; and    passing said casting sheet carrying said hot film through an embossing station.    
     
     
         10 . The process for calendering polymeric vinyl films according to  claim 9 , wherein said resin blend is polyvinyl chloride.  
     
     
         11 . The process for calendering polymeric vinyl films according to  claim 9 , wherein said casting sheet is applied to said hot film at said calendering head.  
     
     
         12 . The process for calendering polymeric vinyl films according to  claim 11 , wherein said casting sheet is applied to a roller of said calendering head for application to said hot film.  
     
     
         13 . The process for calendering polymeric vinyl films according to  claim 9 , wherein said calendering sheet is applied to said hot film between a last nip of calendering head and said embossing station.  
     
     
         14 . The process for calendering polymeric vinyl films according to  claim 13 , wherein said calendering sheet is applied to said hot film by a nip roller.