Coating processes – Coating remains adhesive or is intended to be made adhesive – Heat sensitive adhesive
Reexamination Certificate
1999-02-24
2001-06-12
Pianalto, Bernard (Department: 1762)
Coating processes
Coating remains adhesive or is intended to be made adhesive
Heat sensitive adhesive
C427S208800, C427S412100, C427S099300, C427S420000, C427S428010
Reexamination Certificate
active
06245382
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a protective coating for a data carrying device, a protected data carrying device and methods for making the protective coating and protected data carrying device.
BACKGROUND OF THE INVENTION
Polymeric data carying devices are well-known and include identification cards, telephone calling cards, instant cash cards, credit cards, and company identification cards. Typically, polymeric data carrying devices include a polymeric substrate, on which information, such as a person's name, account number, address, or picture, is imprinted. After the polymeric substrate is customized, the card is typically protected with a clear protective overlay.
Typical protective overlays include a resin such as methyl methacrylate, ethyl methacrylate, vinyl chloride/vinyl acetates, cellulose acetate butyrates and other similar resins. The protective overlay may be applied to the polymeric substrate as a wet lacquer by dissolving the resin in a solvent or carrier. After the lacquer is applied to the substrate, the solvent or carrier is evaporated and the residual resin forms the protective overlay.
Alternately, the protective overlay can be applied to the polymeric substrate as a laminate. In this technique, the resin is first applied to a carrer such as polyester film. To evenly disperse the resin on the film, the protective resin is typically dissolved in a solvent or carrier solution and coated onto the film using a solution coating machine, such as a machine for gravure printing, mayer rod metering, reverse roll, slot die, curtain coating or screen printing. After the solution is applied to the film, the solvent or carrier solution is evaporated, typically by the application of heat. Similarly, a resinous heat sealable adhesive, such as butyl methacrylate or vinyl chloride/vinyl acetate polymers, is coated on top of the protective coating. The resultant protective laminate can then be laminated to the polymeric substrate with the application of heat and pressure. After lamination, the carrier film is stripped away, leaving a protective coating on the card surface which protects images thereon from abrasion, solvent or plasticiser attack.
Other protective laminates include clear films such as polyester, polypropylene, polyvinyl chloride, acetate, etc. that can be laminated to the surfaces of the card. According to this technique, a solution including a heat sealable adhesive is coated onto the clear film. The solvent is evaporated to leave an adhesive layer on the clear film. The film is then die cut to the desired dimensions and hot laminated to the card using a hot roller or hot platen.
Other known protective coatings for data carrying devices include ultraviolet radiation curable (“U.N. curable”) compositions. U.V. curable compositions include monomers and/or oligomers that polymerize upon exposure to U.V. radiation. U.V. curable coatings are generally applied to a data carrying device as a flowable composition and subsequently cured to form a protective coating. U.V. cured protective coatings provide superior abrasion and chemical resistance as compared to other resinous protective coatings due to cross-linking of the monomers and/or oligomers in the coating induced by exposure to U.V. radiation.
However, there are disadvantages associated with U.V. curable compositions. The U.V. curable composition must be exposed to U.N. radiation, thus an end user risks exposure to U.V. radiation. Furthermore, the equipment necessary for curing a U.V. curable composition is both expensive and complex.
A protective coating for data carrying devices that has the superior physical properties of U.V. curable coatings without the disadvantages associated therewith is therefore desirable. It is filrther desirable to have a protective coating that can be applied to a data carrying device by an unskilled end user without significant exposure to hazardous chemicals or need for complex machinery.
SUMMARY OF THE INVENTION
The present invention is directed towards a protective coating having abrasion and chemical resistance of known curable coatings, but which is applied to a polymeric substrate, such as a data carrying device, using an adhesive. Unlike known polymeric laminates, the protective coating of the invention includes a protective layer made from a curable composition. However, instead of applying the curable composition directly to the data carrying device and then curing the curable composition, the curable composition is included in a protective film and cured and then adhered to the data carrying device using an adhesive. Thus, the protective coating of the invention is safe and easy for an end user to apply to a data carrying device. Furthermore, the protective coating of the invention can be applied to the data carrying device in multiple layers. The more layers that are applied, the more protection for the data carrying device. Preferably the curable coating is a U.V. curable coating and the adhesive is a heat sealable adhesive. Preferably the protective coating is applied using a conventional heat lamination process.
The protective film of the invention includes a base film, a protective layer and an adhesive layer. Preferably, the protective film also includes a release layer. Generally, the base film is a flexible sheet of polymers, such as polycarbonate, polyethylene naphthalate or polyester, that finctions as a substrate and carrier for the protective coating of the invention. If present, the release layer is adjacent to the base film. According to the invention, the release layer is a resinous composition that facilitates separation of the base film from the protective coating when the protective coating is applied to a polymeric substrate. Suitable resins for the release layer include acrylics, acrylates, methacrylates, polyesters, polyvinyl butyrals, cellulose acetate butyrates, cellulose acetate propionoates, polyvinyl acetates and polyvinyl chlorides. The protective layer is adjacent to the release layer, if present, and on the opposite side of the release layer from the base film. If no release layer is present, the protective layer is applied directly to the base film. The protective layer is formed by applying a curable composition to the release layer and curing the curable composition. The curable composition includes a polymerizable composition and a solvent, and preferably a polymerization initiator. Preferably, the polymerizable composition includes ethylenically unsaturated monomers and/or oligomers such as acrylates, diacrylates and triacrylates. Preferably, the polymerization initiator is activated by actinic radiation. Preferably the solvent is an organic solvent. Most preferably the curable composition is cured by exposure to ultraviolet (U.V.) radiation. The protective film of the invention also includes an adhesive layer that is adjacent to the protective layer, on side of the protective layer opposite the release layer and base film. Preferably, the adhesive layer includes a heat sealable adhesive. Preferably the adhesive layer includes resins such as acrylics, ethyl methacrylate, polyvinyl acetate, butyl methacrylate, methacrylate copolymers, polyester, copolyester and/or vinyl chloride/vinyl acetate copolymers.
The invention is also directed towards methods of making the protective film of the invention. According to one embodiment of the invention, the protective film is made using a one-step curing process. According to this embodiment, a release composition which includes a resinous component is applied to a base film (if a release layer is present in the protective coating). Preferably the release composition includes a solvent. If a solvent is included in the release composition, the solvent is evaporated from the release composition after application to the base film. The remaining resinous material forms the release layer. A curable composition is then applied to the release layer. if no release layer is present, the curable composition can be applied directly to the base film. The curable composition includes a p
Knipp Roman T.
Shvartsman Felix P.
DataCard, Inc.
Merchant & Gould P.C.
Pianalto Bernard
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