Stock material or miscellaneous articles – Layer or component removable to expose adhesive – Protective layer
Reexamination Certificate
1998-11-13
2001-10-16
Cole, Elizabeth M. (Department: 1771)
Stock material or miscellaneous articles
Layer or component removable to expose adhesive
Protective layer
C428S041800, C428S354000, C428S343000
Reexamination Certificate
active
06303203
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an optically clear layer for application to images on substrates.
BACKGROUND OF THE INVENTION
Electronic graphics produced via electrographic processes, inkjet processes, and the like, is rapidly becoming a preferred method for the formation of images. The Scotchprint™ Electronic Graphics Systems commercially available from Minn. Mining and Manufacturing Company of St. Paul, Minn. (“3M Company”) uses an electrostatic process for forming an image and transferring that image to a durable substrate. One description of the process is found in U.S. Pat. No. 5,114,520 (Wang et al.).
The image formed on a durable substrate requires protection from abrasion and ultraviolet light. An optically clear, transparent overlaminate, comprising an optically clear, transparent durable film covered on a major surface by an optically clear, transparent pressure sensitive adhesive, is preferably applied over the image on the durable substrate. Commercially available clear, transparent overlaminates include Product Nos. 8910, 8911, 8912, 8913, 8920, 8930, and 8931 films from the Commercial Graphics Division of 3M Company, St. Paul, Minn. Of these, 8913 and 8930 are optically clear. Some of the clear, transparent overlaminates include a vinyl or polyester film covered with a pressure sensitive adhesive, which is in turn is protected by a paper or polyester liner until usage. Other clear, transparent overlaminates include a vinyl or polyester film covered with a hot melt adhesive, and a scrim liner to prevent blocking.
In the absence of the use of a clear, transparent overlaminate, some fabricators apply a protective clear coat of a vinyl/acrylic material, such as Product Nos. 3920, 8920, 9720, 6620I, and 2120 protective coatings from the Commercial Graphics Division of 3M Company to protect the durable, imaged substrate. But such application of a liquid to a solid flat surface is subject to the inconsistencies of climate, circumstances, and craftsmen.
While the optically clear, transparent overlaminates known in the art are quite acceptable for large format graphics uses, vinyl-based optically clear, transparent overlaminate films remain extremely elusive to achieve.
SUMMARY OF THE INVENTION
The art of electronic graphics needs an inexpensive, durable, optically clear, transparent layer to protect images formed on a major surface of substrates, when compared to other transparent layers known to those skilled in the art. This is especially true when the substrate is a perforated film with holes to allow viewing through the non-imaged surface.
One aspect of the present invention is an inexpensive, durable, optically clear, transparent layer formed on a polymeric release liner that has preferred surface properties to permit the layer of the present invention to have optical clarity within acceptable ranges.
A layer to cover and protect an imaged substrate comprises a composition comprising vinyl chloride resin, optional acrylic resin, optional plasticizer, and optional stabilizer, wherein the composition is formed on a polymeric release liner having thickness values from about 0.05 mm (0.002 inches) to about 0.12 mm (0.005 inches).
Another aspect of the present invention is a method of forming an inexpensive, durable, optically clear, transparent layer formed on an image residing on a durable substrate. A method of forming the layer comprises the steps of forming the optically clear, transparent layer having two major surfaces from an organosol on a first polymeric release liner having a thickness ranging from about 0.05 mm (0.002 inches) to about 0.127 mm (0.005 inches); optionally adhering a field of pressure sensitive adhesive to a second release liner; and optionally laminating the field of pressure sensitive adhesive to an exposed major surface of the optically clear, transparent layer; and optionally removing the first polymeric release liner.
Another aspect of the invention is a composite of an inexpensive, durable, optically clear, transparent layer covering a durable, imaged substrate. A composite comprises an optically clear, transparent layer covering a durable, imaged substrate, wherein the optically clear, transparent layer identified above.
A feature of the invention is the formation of the durable, optically clear, transparent layer on a polymeric release layer from a thermally processable composition, wherein the surface properties of the polymeric release layer determine the optical clarity of the layer of the present invention.
Another feature of the invention is the transfer of the durable, optically clear, transparent layer from the second release layer to the durable, imaged substrate.
An advantage of the invention is the ability to transfer the optically clear, transparent layer from a release layer to an imaged substrate.
Another advantage of the invention is the ability of the durable, optically clear, transparent layer to provide stabilization and protection from abrasion and ultraviolet light degradation.
Therefore, the present invention also includes a method of protecting an imaged substrate, comprising the steps of forming a layer of the present invention on a polymeric release liner; and laminating the layer of the present invention to the imaged substrate.
Embodiments of the invention are described with reference to the following drawings.
REFERENCES:
patent: 5085907 (1992-02-01), Smith
patent: 5114520 (1992-05-01), Wang, Jr. et al.
patent: 5370960 (1994-12-01), Cahill et al.
patent: 5397634 (1995-03-01), Cahill
patent: 5647935 (1997-07-01), Hoshino
patent: 5681660 (1997-10-01), Bull et al.
patent: 5869179 (1999-02-01), Cahill
patent: WO 93/22137 (1993-11-01), None
Richard J. Lewis, Sr., Hawley's Condensed Chemical Dictionary, 13thed., (1997), p. 825.
Patent Abstract of Japan-JP60195146; Nippon Carbide Kogyo KK; Oct. 3, 1985.
Patent Abstracts of Japan-JP62074910; Toyo Soda Mfg Co Ltd.; Apr. 6, 1987.
Research Disclosure-No. 323, (1991) Mar.; p. 198 XP 000176287 “Improvement of Image Surface Quality by Planarization with a Second Index-Matching Medium”.
3M Innovatives Properties Company
Bjorkman Dale A.
Cole Elizabeth M.
Singh Arti R.
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