Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
1999-08-13
2001-12-18
Zirker, Daniel (Department: 1771)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S343000, C428S3550AC, C428S906000
Reexamination Certificate
active
06331352
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to correction tapes having dye migration blocking properties. More specifically, the present invention includes a correction tape having a dye migration barrier. The dye migration barrier comprises an organic material that serves as a physical barrier to prevent ink dye from markings covered by the correction tape from migrating to an upper visible surface of the correction tape. Additionally, the present invention is directed to a process for the manufacture of a correction tape having a dye migration barrier.
Correction tape is a commonly used method to cover markings. The tape typically comprises two parts, a polymeric support member as a base and a correction medium releasably attached to the base. A correction medium may be multi-layered, and may contain pigments, fillers, such as clay, a polymeric binder and dispersant to anchor the pigments to the paper, as well as, a dispersant medium or solvent to maintain fluid viscosity. The correction medium is later transferred onto paper to cover markings once pressure is applied on the tape.
Conventional correction tapes typically allow ink dyes from the covered markings to bleed through the applied correction medium. The dissolution of the underlying ink dyes from the reaction of the ink dye with the correction medium causes the so-called bleeding or smudging of the markings into the correction medium, which discolors the correction medium on the corrected marking. Bleeding causes the typically white correction medium to assume a bluish or reddish tint or other type of blemish color due to the ink dye migrating toward the upper visible surface of the layer of correction medium. This bleeding effect is a known shortcoming of conventional correction tapes.
Correction fluids have been developed to solve the problem of bleed-through. See, European Publication No. 0 647 689 A1, PCT Publication No. WO 92/07039, PCT Publication No. WO 94/29393, PCT Publication No. WO 96/01878, and PCT Publication No. WO 98/30641.
Japanese Patent No. 2,692,642 discloses a correction tape comprising a correction material, a metal thin film layer, and an adhesive layer. The metal thin film layer provides a masking effect. The correction medium layer has the same color tone as that of a plain paper effected by incorporating a white pigment into a resin material or by providing a white printing layer on the surface of the base material layer. The correction tape manufactured with a metal thin film layer is costly because the metal thin film layer is applied using specialized vapor deposition techniques instead of standard layering techniques. Additionally, the vapor deposition of a metal requires harsh manufacturing conditions that strain the correction medium layer such as high temperatures, low pressures, and drying periods under vacuum.
Some of the commercially available correction tape products are made using polymers dissolved in organic solvents which provide some protection against bleeding, however, environmental regulations restrict the use of organic solvents on an industrial scale due to pollution problems. Measures taken to decrease the environmental impact of the use of organic solvents increase production costs of correction tapes. Other commercial products do not have adequate bleed inhibiting characteristics.
Despite these efforts correction tapes having better bleed through resistance are still desired by the industry. As new water and solvent based ink compositions are developed, new compositions and formulations of correction tapes are necessary to maintain good bleed through resistance.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a correction tape that inhibits bleed-through through the correction medium when applied to printed or ink dye markings.
Another object of the present invention is to provide a manufacturing process for a correction tape with a dye migration barrier.
Another object of the present invention is that film integrity of the correction tape is improved thus avoiding premature breakage, as found in current correction tapes.
Yet another object of the present invention is to provide a manufacturing process that does employ environmentally friendly chemicals and chemical processes.
The present invention is directed to a correction tape comprising at least one support member, at least one correction medium, at least one dye migration barrier, and at least one pressure sensitive adhesive layer. The support member retains a correction medium, dye migration barrier and an adhesive layer. Typically the support member is paper, thermoplastic film, a metallic foil, or a coated glassine paper to facilitate removal of the correction medium. Optionally, the support member can be coated with a releasing agent, such as a polyolefin, polysiloxane, polyfluoroolefin, or a mixture thereof. The dye migration barrier is present in an amount sufficient to prevent ink from migrating through at least the dye migration barrier and retain correction medium integrity when the correction medium is transferred to a surface. The dye migration barrier is typically an organic polymer or copolymer made of acrylate, methacrylate, styrene, styrene acrylic, styrene butadiene, vinyl acetate homopolymer, a low volatile organic compound, vinyl acetate, vinyl acetate ethylene, cellulose, or copolymers thereof. Preferably, the organic polymer comprises at least one ethylene, vinyl acetate, ethylene vinyl acetate, or copolymers thereof. The dye migration layer thickness may be between about 1 micron to about 100 microns in thickness, preferably, between about 3 microns to about 45 microns.
The pressure sensitive adhesive typically includes at east one organic polymer made from monomers of acrylic, ethacrylic, or a mixture thereof.
Another aspect of the present invention includes a process for the manufacture of a correction tape having the steps of providing a support member; applying a correction material in a sufficient amount onto the support member to form a first layer, a correction medium, preferably with a thickness of between about 40 to about 60 microns when wet; allowing the first layer to dry to form a correction medium; applying an organic polymer to the first layer in a sufficient amount to form a second layer, preferably with a thickness of between about 3 micron to about 5 microns; allowing the second layer to dry to form a dye migration barrier; applying an adhesive material to the second layer in a sufficient amount to form a third layer; and allowing the third layer to dry.
Optionally, the process includes a curing step wherein either the first, second, or third layer is allowed to cure after drying, at about room temperature and for a minimum time of about 24 hours. Optionally, the process includes coating the support member with a releasing agent such as polyolefin, polysiloxane, polyfluoroolefin, or a mixture thereof in a sufficient amount to facilitate the release of the correction medium and dye migration barrier from the support member. The process may include a step wherein the correction tape is slitted to a width of about 4.2 mm.
The drying step within the process can be performed in a drying tunnel having at least one IR lamp, convection oven, hot air blower, or a combination thereof.
The organic polymer of the process can be at least one acrylate, methacrylate, styrene, styrene acrylic, styrene butadiene, vinyl acetate homopolymer, a low volatile organic compound, vinyl acetate, vinyl acetate ethylene copolymer, cellulose, or copolymers thereof, preferably at least one of ethylene, vinyl acetate, ethylene vinyl acetate, or copolymers thereof. The releasing agent can be a polyolefin, polysiloxane, polyfluoroolefin, or a mixture thereof.
REFERENCES:
patent: 5221577 (1993-06-01), Inaba et al.
patent: 5700552 (1997-12-01), Katsuro et al.
patent: 5997994 (1999-12-01), Matsushima
patent: 647689 (1995-12-01), None
patent: 647689 A1 (1995-12-01), None
patent: 727378 A1 (1996-08-01), None
patent: 8258494 (1996-10-01), None
patent: WO 92/07039 (19
Bradley Creg G.
Gabriele Peter D.
Hopper Teresa B.
Bic Corporation
Pennie & Edmonds LLP
Zirker Daniel
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