Apparatus for applying protective films

Abstract

An improved method of protecting finished surfaces of, for example, automobiles replaces the prior art methods of spraying and hand laying large plastic sheets. In this method a slotted die extrudes a ribbon of a polymeric emulsion onto the surface to be protected under robotic control so as to maintain a constant spacing between die and surface. The die can be moved quickly and with great precision. The applied film is cured and, at a later time, is peeled from the surface.

What is claimed is: 
     
         1 . A method of applying a peelable film of a cured polymeric emulsion to the painted surface of an article of manufacture comprising the steps of:
 a. supplying an emulsion of a polymer to an extrusion die having a body with a long, narrow slot-shaped outlet;   b. robotically moving the die over said surface while maintaining a constant distance between the die outlet and the surface;   c. extruding said emulsion onto said surface in the form of a non-atomized ribbon of said material through said outlet while moving the die relative to the surface and maintaining said predetermined distance to adhere one or more ribbons to said surface; and thereafter,   d. curing the applied ribbon or ribbons of film.   
     
     
         2 . The method defined in  claim 1  wherein the viscosity of the emulsion is between about 3,000 and 12,0000 centipoise at a predetermined operating temperature. 
     
     
         3 . The method defined in  claim 1  wherein the distance between the die outlet and the finished surface is about 15 mm. 
     
     
         4 . The method defined in  claim 1  including the further step of maintaining the temperature of the body at said predetermined operating temperature. 
     
     
         5 . The method defined in  claim 1  including the further step of peeling the cured applied ribbon from the article. 
     
     
         6 . The method defined in  claim 1  wherein the thickness of the applied ribbons is about 200 microns. 
     
     
         7 . The method defined in  claim 1  wherein the robot moves the die body during application of said ribbons at a speed of between 1,500 mm and 2,000 mm per second. 
     
     
         8 . The method defined in  claim 1  wherein the robot applies multiple ribbons in overlapping strokes. 
     
     
         9 . The method defined in  claim 1  wherein the polymer is PVA. 
     
     
         10 . The method defined in  claim 1  wherein the article of manufacture is a painted automobile body component.