Method of increasing dielectric break-down strengths of thermoplastic films

Abstract

A method is provided of increasing the dielectric breakdown strength of tmoplastic films such as thin films of polypropylene obtained from polypropylene resin powder. The method involves melt extruding the resin powder with a small amount of ceresine wax.

What is claimed is: 
     
       1. Method of increasing the dielectric breakdown strength of thin thermoplastic films from a thermoplastic resin powder comprising melt extruding the resin powder with a small amount of a hydrocarbon that can act as a trapping center for electrons. 
     
     
       2. Method according to claim 1 wherein the thermoplastic resin is selected from the group consisting of polypropylene, polyethylene, polyvinylidene fluoride, and trifluoroethylene and copolymers of these materials and wherein the hydrocarbon that can act as a trapping center for electrons is selected from the group consisting of ceresine wax, naphthalene, anthracene, and paraffins. 
     
     
       3. Method according to claim 2 wherein the thermoplastic resin is polypropylene and wherein the hydrocarbon that can act as a trapping center for electrons is ceresine wax. 
     
     
       4. Method according to claim 3 wherein the small amount of ceresine wax is about one weight percent to about two weight percent. 
     
     
       5. A thin thermoplastic resin film with a small amount of a hydrocarbon that can act as a trapping center for electrons uniformly distributed throughout the resin films. 
     
     
       6. A thin thermoplastic resin film according to claim 5 wherein the thermoplastic resin film is selected from the group consisting of polypropylene, polyethylene, polyvinylidene fluoride, trifluorethylene, and copolymers of these materials and wherein the hydrocarbon that can act as a trapping center for electrons is selected from the group consisting of ceresine wax, naphthalene, anthracene and paraffins. 
     
     
       7. A thin thermoplastic resin film according to claim 6 wherein the thermoplastic resin is polypropylene and wherein the hydrocarbon that can act as a trapping center for electrons is ceresine wax.