Compositions – Organic luminescent material containing compositions
Reexamination Certificate
1999-06-24
2001-04-24
Koslow, C. Melissa (Department: 1755)
Compositions
Organic luminescent material containing compositions
C101S491000, C427S157000, C106S031150, C106S031650, C106S499000, C106S413000
Reexamination Certificate
active
06221279
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a pigment composition for invisibly marking a substrate and more particularly to a modified thermoplastic polyester containing a near infrared fluorescing compound. Advantageously, the pigment can be milled to a finely divided solid having an average particle size of less than about 20 microns. The pigment of the present invention may be used as a security ink or for document authentication, sensing marks, invisible identification marks or admixed into plastics and the like. The pigment may be applied using known techniques such as letterpress, flexographic, lithographic and gravure.
BACKGROUND OF THE INVENTION
Fluorescent pigments are will known in commerce and have many uses. Pigments prepared from a frangible polymer into which a fluorescent dye has been dissolved are particularly well known. The dyes are usually those which fluoresce in daylight to produce very brilliant colors. They are widely used in inks and coatings, especially for outdoor signs. U.S. Pat. Nos. 5,470,502; 3,922,232; 3,812,051 and 3,812,053 are but a few patents that disclose these types of fluorescent dyes.
In recent years, there has been a great deal of interest in methods for marking various products and substrates in a way that the markings are poorly visible or invisible in the visible wavelength, i.e., 400 nm to about 700 nm but which may be detected by means of their fluorescence when they are excited or irradiated with an energy in the near infrared or infrared wavelength region. For example, U.S. Pat. No. 5,093,147 describes an ink containing dyes which are poorly absorptive of radiation in the visible range of about 400 nm to 700 nm but are highly absorptive of radiation in the near infrared range of at least about 750 nm. Those materials which absorb radiation in the near infrared range of 650-1100 nm and fluoresce at a somewhat longer wavelength than that at which they absorb are referred to as near infrared fluorophores.
U.S. Pat. No. 5,525,516 discloses a method for imparting invisible markings for identification purposes to petroleum hydrocarbons using one or more infrared fluorophores selected from the classes of phthalocyanines, squaraines and naphthalocyanines.
Near infrared fluorescing compounds may be mono or multi-functional and may be copolymerized into a variety of condensation polymers. Suitably functionalized near infrared fluorescing compounds may be incorporated into certain polyesters to render the near infrared fluorescing compounds water dispersible. For example, U.S. Pat. No. 5,614,008 discloses an ink composition having a water dissipatable polyester having a near infrared compound copolymerized in the polyester. The ink is useful for invisibly marking a variety of substrates.
U.S. Pat. No. 5,461,136 discloses a method for tagging thermoplastic containers using a near infrared fluorescing compound that is admixed or copolymerized with the thermoplastic material. The incorporation of such near infrared fluorescing compounds into the thermoplastic assists in the separating and sorting of thermoplastic containers such as bottles.
Accordingly, there is a need for a pigmentary form of a near infrared fluorescing compound that may be used in various printing applications and ink formulations.
SUMMARY OF THE INVENTION
The present invention provides a fluorescent pigment composition that is useful for identification tagging various substrates where use of a pigment would be beneficial, such as for example, letterpress applications, lithographic applications, thermal transfer applications, and gravure printing operations. Briefly, the fluorescent pigment composition includes a crystalline thermoplastic polyester resin having residues of at least one dicarboxylic acid and having an intrinsic viscosity (IV) of less than about 0.37; and a near-infrared fluorescing compound having a fluorescence between about 650 nm to about 2500 nm associated with the crystalline thermoplastic polyester.
Another aspect of the present invention there is provided a method for marking a surface of a substrate with an ink composition which includes the pigment composition of the present invention. The method includes the steps of providing a near infrared fluorescing pigmentary compound and applying the pigment compound to a substrate.
It is an object of the invention to provide a thermoplastic pigment having a near infrared fluorescing compound associated with the thermoplastic.
It is another object of the invention to provide a thermoplastic pigment that may be milled to a size of less than about 20 microns.
Yet another object of the invention is to provide a method for marking a substrate using a pigment composition containing a near infrared fluorescing compound.
It is another object of the invention to provide a polyester pigment having a near infrared fluorescing compound associated with the polyester having improved compatibility with thermoplastic materials.
Numerous other objects and advantages of the present invention will become readily apparent from the following detailed description of the preferred embodiments and the appended claims.
REFERENCES:
patent: 3764576 (1973-10-01), Russo
patent: 3812051 (1974-05-01), Merkle et al.
patent: 3812053 (1974-05-01), Siegfried et al.
patent: 3838063 (1974-09-01), Foss
patent: 3873491 (1975-03-01), Gall
patent: 3922323 (1975-11-01), Schein
patent: 4044073 (1977-08-01), Baron et al.
patent: 4107149 (1978-08-01), Bier et al.
patent: 4117194 (1978-09-01), Barbe et al.
patent: 4186168 (1980-01-01), Barbe et al.
patent: 4254290 (1981-03-01), Chambers et al.
patent: 4346213 (1982-08-01), Hall, Jr. et al.
patent: 4351758 (1982-09-01), Lu et al.
patent: 4369280 (1983-01-01), Dieck et al.
patent: 4439597 (1984-03-01), Hall, Jr. et al.
patent: 4444931 (1984-04-01), Lu et al.
patent: 4485212 (1984-11-01), Wefer
patent: 4499261 (1985-02-01), Heinze et al.
patent: 4536531 (1985-08-01), Ogawa et al.
patent: 4547547 (1985-10-01), Chen et al.
patent: 4599375 (1986-07-01), Berte et al.
patent: 4622179 (1986-11-01), Eda
patent: 4654413 (1987-03-01), Takahashi
patent: 4656241 (1987-04-01), Iida et al.
patent: 4713408 (1987-12-01), Takahashi et al.
patent: 4739012 (1988-04-01), Hagman
patent: 4742109 (1988-05-01), Takahashi et al.
patent: 4814441 (1989-03-01), Hauser et al.
patent: 4942188 (1990-07-01), Hamersma et al.
patent: 4954542 (1990-09-01), Bohen et al.
patent: 5030670 (1991-07-01), Hirahara et al.
patent: 5032670 (1991-07-01), Parham et al.
patent: 5034439 (1991-07-01), Breitenfellner et al.
patent: 5093147 (1992-03-01), Andrus et al.
patent: 5096653 (1992-03-01), Nedzu
patent: 5101064 (1992-03-01), Dupont et al.
patent: 5102980 (1992-04-01), Krutak et al.
patent: 5106942 (1992-04-01), Krutak et al.
patent: 5108806 (1992-04-01), Nedzu et al.
patent: 5108818 (1992-04-01), Ebina et al.
patent: 5115022 (1992-05-01), Bronstert et al.
patent: 5153065 (1992-10-01), Abu-Isa
patent: 5162424 (1992-11-01), de Boer et al.
patent: 5183840 (1993-02-01), Erpelding et al.
patent: 5237042 (1993-08-01), Kim et al.
patent: 5258434 (1993-11-01), Hanabusa
patent: 5264153 (1993-11-01), De Krom
patent: 5266601 (1993-11-01), Kyber et al.
patent: 5273810 (1993-12-01), Nakano et al.
patent: 5292855 (1994-03-01), Krutak et al.
patent: 5319128 (1994-06-01), Dupont et al.
patent: 5321086 (1994-06-01), Kozakura et al.
patent: 5340875 (1994-08-01), Yang et al.
patent: 5346802 (1994-09-01), Ohbachi et al.
patent: 5378854 (1995-01-01), Hamersma et al.
patent: 5397819 (1995-03-01), Krutak et al.
patent: 5420199 (1995-05-01), Fujie
patent: 5422161 (1995-06-01), Ohbachi et al.
patent: 5441997 (1995-08-01), Walsh et al.
patent: 5442000 (1995-08-01), Kato et al.
patent: 5460646 (1995-10-01), Lazzouni et al.
patent: 5470502 (1995-11-01), Hahn et al.
patent: 5553714 (1996-09-01), Cushman et al.
patent: 5837042 (1998-11-01), Lent et al.
patent: WO 92/07913 (1992-05-01), None
Cyr Michael John
Kendrick Crystal Leigh
Strand Marc Alan
Casperson John R
Davis Mark L.
Isotag Technology, Inc.
Koslow C. Melissa
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