Abstract Excellent adhesion of gelatinous and other coatings to oriented and unoriented polymeric film is achieved under both dry and wet conditions. The polymeric film is transported through an elongated coruscate electrical discharge field generated by a high voltage alternating current source on one side of the polymeric film, and which appears similar to an oxidizing flame. The opposite side of the polymeric film is transported in engagement with a conducting surface causing the electrical discharge field to penetrate the film as it moves through and along the coruscate electrical discharge field. Polymeric film treated by the coruscate electrical discharge field has improved adhesive qualities for use in, among other things, heat sealing operations in which a plastic film is heat sealed to the polymeric film, and photographic coating and subcoating operations in which a photographic emulsion, nucleating layer, actinic radiation-sensitive layer, or the like is coated onto the polymeric film.
The invention according to claim 1 wherein said elongated member is a threaded rod having approximately 32 threads per inch of length.
Claim 2
Dependent Claim
23 words
The invention according to claim 1 wherein said high voltage alternating current power supply generates substantially 34 kilovolts at 5 milliamps, 60 hertz.
Claim 3
Dependent Claim
44 words
The invention according to claim 1 wherein said elongated member is a threaded rod having approximately 32 threads per inch of length and further having rounded ends, and said high voltage alternating current power supply generates substantially 34 kilovolts at 5 milliamps, 60 hertz.
Claim 4
Dependent Claim
49 words
THe invention according to claim 1 wherein said electrically conducting means is provided with a dielectric support surface for supporting each side edge of the film, said apparatus further having air nozzles for directing air under pressure across the edges of the film in engagement with said conducting means.
Claim 5
Dependent Claim
51 words
The invention according to claim 1 wherein said electrically conducting means comprises a metal roller provided with dielectric end caps for supporting each side edge of the film, said apparatus further having air nozzles for directing air under pressure across the edges of the film in engagement with said metal roller.