Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2001-06-01
2003-11-25
Bell, Mark L. (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031750, C106S031770, C106S031860, C106S031690, C106S031880, C523S160000, C523S161000
Reexamination Certificate
active
06652638
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a UV sensitive marking composition, and more particularly to a marking composition that progressively fades under exposure to UV light until it is substantially invisible.
BACKGROUND OF THE INVENTION
Surface marking has been widely practiced in the construction and survey industries. For example, highly visible site marks are needed to indicate the location of underground utilities. Surface marking is also used in landscape surveys, traffic marking, athletic field marking, and aisle striping in parking lots.
In certain situations, especially for survey marking or construction site marking, it is desirable to minimize unsightly locator marks in visually sensitive areas after the construction or surveys are completed. Therefore, there is a need for a UV-sensitive marking composition that fades to such an extent that it will not be visually disturbing, after the marking purposes have been accomplished.
Moreover, it has been shown that UV-sensitive marking compositions utilizing UV-sensitive pigments, rather than dyes, demonstrate better contrast between the marking composition and the surface to which it is applied. Additionally, UV-sensitive pigments remain visible for longer than UV-sensitive dyes. This is an important consideration in surveying and construction, where a user may mark a particular site, but then not return to the site for several weeks.
Accordingly, a need exists for a marking composition that utilizes pigments, and the advantages associated therewith, while at the same time being of a temporary nature-such that the marks do not remain after the purpose of the marks has been accomplished.
PRIOR ART
Examples of patents related to various marking compositions, each of which is incorporated by reference for its supporting teachings, are as follows:
U.S. Pat. No. 5,714,090 to Waters et al. discloses a non-formaldehyde thermoset fluorescent pigment which is used to color plastics, particularly flexible vinyl, and which is solvent resistant, particularly to acetone. Moreover, the pigment does not bleed in plastics. The pigment comprises a polymer matrix and a fluorescent dye. The polymer matrix has a molecular weight of greater than about 330, preferably greater than about 1000. Embodiments which lack the water insoluble resin, have a molecular weight greater than about 330, preferably greater than about 500. The polymer matrix contains: from about 15 to 50 mole percent, preferably 30 to 40 mole percent, of a carboxylate functional oligomer; 30 to 80 mole percent, preferably 50 to 60 mole percent, of a metal ion; and 0 to 40 mole percent, preferably about 1 to 40 mole percent, more preferably from 1 to 30 mole percent, most preferably from about 3 to 10 mole percent of a water insoluble resin. In embodiments where no water insoluble resin is used, the metal is present from at least 51 mole percent. The oligomer comprises from about 10 to about 60 mole percent, preferably 20 to 35 mole percent of a first monomer, 40 to 90 mole percent, preferably 65 to 80 mole percent of second monomer. The weight average molecular weight of the oligomer is 330 to 2000, preferably about 560 to 600. The invention also relates to a novel method for producing the fluorescent pigments.
U.S. Pat. No. 6,103,006 to DiPietro discloses thermoplastic, non-water soluble, fluorescent pigments having improved lightfastness and which are suitable for coloring a variety of materials including plastics, particularly polyolefins, as well as paints, inks and textiles. The pigments, referred to herein as the “light fast pigments”, demonstrate good color, migration resistance, heat stability, water insolubility, friability and resistance to plateout. The light fast pigments have several embodiments, the polyamide embodiment, polyamide ester embodiment and the polyester embodiment. The pigments comprise a polymer which comprises polymerized units of fluorescent dye and polymerized monomers such as for example dicarboxylicacids, polycarboxylicacids, diamines, polyamines, alkanolamines, carboxyalcohols, carboxyamines and difunctional alcohols, and/or polyhydric alcohols. The polyamide pigment embodiment and polyamide-ester pigment embodiment are polymers which comprise polyamide linkages. The polyester pigment embodiment are polymers that comprise polyester linkages, but substantially lacks polyamide linkages. The light fast pigments contain a fluorescent dye reacted into, and covalently bound to the polymer backbone; this distinguishes the light fast pigment from conventional pigments which typically exist as a solid state solution of fluorescent dye and polymer carrier. In the polyester pigment embodiment, the fluorescent dye, which is physically incorporated into the backbone of polymer chain, is the BXDA fluorescent dye or an analog thereof. In the polyamide pigment and polyamide-ester pigment embodiments, the fluorescent dye is the BXDA fluorescent dye or its analogs thereof, or certain conventional dyes. While the light fast pigment demonstrates improved lightfastness, the addition of an optional light stabilizer enhances the lightfastness of the pigment. The invention also relates to a method of making such light fast pigment.
U.S. Pat. No. 5,548,010 to Franer discloses a color additive, which when added to paints, whether water-based or oil-based, varnishes, sealers, lacquers, and other protective or decorative compositions, and to additives therefor, and when applied on a surface provides for a color that dissipates within a reasonable time frame, generally from hours to a few days leaving the paint the original color. The color additives temporarily impart color to paint, the color dissipating over a short period of time substantially to the color of the original composition prior to the addition of the colorant thereto, whether they are water white, tinted or pigmented. A method of temporarily imparting a fugitive color to paint is also disclosed.
None of the foregoing prior art references address the need for a marking composition that utilizes UV-sensitive pigments, and the advantages associated therewith, while at the same time being of a temporary nature—such that the marks do not remain after the purpose of the marks has been accomplished.
SUMMARY OF THE INVENTION
A marking composition for placing a temporarily visible mark on a surface is therefore provided. The marking composition of the present invention includes a paint base and a pigmented colorant. The colorant is dispersed within the paint base, and has characteristics that cause the mark to progressively become substantially invisible upon exposure to UV light. In one embodiment, UV absorbers and/or anti-oxidants are added. These additives effect the rate at which the mark becomes invisible.
The pigmented colorant may be a dispersion of dyed melamine-toluenesulfonamide-formaldehyde polymer in a mixture of alkyl based resins and aliphatic hydrocarbons. The colorant can be about 2-30 parts by weight of the marking composition. A variety of colors may be selected for the pigmented colorant. For example, the colorant may have a color selected from the group consisting of red, orange, yellow, pink, blue and green. More particularly, the colorant may be a Special Fugitive Colorant, which is a dispersion of a dyed melamine-toluenesulfonamide-formaldehyde polymer in a mixture of alkyd based resins and aliphatic hydrocarbons, made by and commercially available from Day-Glo Color Corporation of Cleveland, Ohio. Examples of suitable Special Fugitive Colorants include: Special Fugitive Yellow Dispersion, No. 121M6669; Special Fugitive Orange Dispersion, No. 121M6665; Special Fugitive Red Dispersion, No. 121M6850; Special Fugitive Red Dispersion; No. MT6633; Special Fugitive Pink Dispersion, No. 121M6832; Special Fugitive Green Dispersion No. 121M6853.
In one embodiment, the paint base comprises a binder, a solvent and paint additives. The binder may be about 8 to 45 parts, the solvent may be about 10 to 60 parts and the paint additives may be about 1 to 15 parts, by weight of the marking c
Finke Christopher P.
Fox Neil S.
Aervoe Pacific Company, Inc.
Bell Mark L.
Faison Veronica F.
Jones Waldo Holbrook & McDonough
Winder Brent T.
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