| abstract |
The present invention concerns methods and apparatus for laminating polymeric sheet materials wherein the use of a separate adhesive and/or the use of heat as a bonding means are avoided. In particular, methods and apparatus are disclosed wherein at least one polymeric sheet is exposed to a flowing of gaseous cold plasma to form free radicals on the surface thereof. Said free radicals serve to effect bonding upon application of such treated polymeric sheet to a second polymeric sheet. In preferred embodiments, approximately 180,000 to 500,000 volts of electromagnetic energy are applied to a stream of gaseous material, such as argon gas, and utilizing a radio wave frequency discharge of approximately 12.56 mega-Hertz. In some preferred embodiments, the cold plasma may be applied at an effective pressure of approximately 1.1 Torr in the reaction area. |