Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Process of making developer composition
Reexamination Certificate
2002-11-20
2004-03-16
Wu, David W. (Department: 1713)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Process of making developer composition
C525S334100, C524S501000, C430S110400, C430S137100, C106S031130, C106S031270
Reexamination Certificate
active
06706460
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to loaded latex particle compositions containing a specific class of infrared dye. Such compositions are particularly useful for making ink formulations which may be used for invisible markings. Processes for making the composition and methods for making various elements using the compositions form other aspects of the invention.
DESCRIPTION RELATIVE TO THE PRIOR ART
Logos are often printed on objects using dyes for cosmetic purposes or as authentification needs. Marks may be a corporate name or other identifying trademarked symbols. For cosmetic reasons the visible color is chosen with great scrutiny. In fact, the actual color may be the most important element of authentification. A more sophisticated means of making a mark useful for authentification is to make the component that is unique invisible to the naked eye. One such way is to use a dye of very low concentration or even more ideally one which absorbs outside the visible region, preferably in the infrared. In fact, many applications in the art describe the use of infrared dyes for security marking purposes. However, dyes that absorb in the infrared region are generally not stable in solution or in air and are particularly susceptible to light fade. This degradation renders them useless for most applications without the presence of a stabilizer. When a dye is used for security or authentification elements, the degradation of this dye eventually results in the inability to recognize the authentification element.
Additionally, there are several reasons why one might want to apply an infrared dye containing composition to the surface of an element carrying a photographic image. For example, a protective overcoat including the infrared absorbing dye can be applied as a final overcoat to assist in the stabilization of the underlying dye stability in an inkjet print. In another embodiment, information can be encoded using an infrared absorbing ink that is invisible to the naked eye over the surface of a photographic print. The information that is in coated on the surface of the print can be, for example, sound information and the like, for example, in U.S. application Ser. No. 09/223,859 filed Sep. 13, 2000. The sound information can be encoded, for example, using bar coding, or some other form of the digital encoding. The surface of the print can then be “played” using a suitable infrared dye detecting apparatus. In another embodiment a surface may need to be marked for simple detection of such mark by silicon based detectors. Such marks can be used to identify an element for further downstream processing events. The same types of stabilization issues exist for the use of infrared dye compositions on photographic elements.
Dye stabilization is well known in the art. Mitsubishi Kasai (EP 0 483 387 A1) and TDK Corp. (U.S. Pat. No. 4,713,314) describes the use of cyanine dyes combined with metal stabilizers. Nickel formazan dyes have been described by Kodak as stabilizers for infrared dyes (U.S. Pat. No. 5,547,728). Additionally, metal dithiolene dyes alone have been disclosed as useful stable dyes for bar coding applications by Kodak (U.S. Pat. No. 4,753,923).
A further limitation on the use of infrared dyes has been solubility issues. One solution to this problem has been the use of loaded latex particles. Loaded latex particles are known for use in a variety of photographic and non-photographic applications. For example, in U.S. Pat. No. 4,237,194 there is described an antistatic composition that uses a polyaniline salt loaded on a polymer latex particle. Coating of the latex composition, followed by drying and core lessons of the latex, produces a suitable antistatic layer. It is also known to load latex particles with fluorescent labels in immunology research (see, for example, U.S. Pat. No. 4,259,313). Also, multiple fluorescent dyes can be loaded onto the same latex particle to achieve useful results (see, for example, U.S. Pat. Nos. 5,326,692 and 5,919,850). U.S. Pat. No. 5,852,074 discloses the use of latex compositions for inkjet inks. U.S. Pat. Nos. 4,401,787; 4,304,769; and 5,594,047 describe various methods of manufacturing loaded latex compositions and discuss the use of such compositions in photographic elements.
U.S. Pat. No. 6,361,916 B1 describes making latex dispersions of infrared dyes. The latex loading allows dispersion of otherwise aqueous insoluble dyes into aqueous solutions. It also allows more efficient dye stabilization due to increased proximity of dye and a co-loaded stabilizer. It further describes photographic elements where those infrared dispersions were added as an additional layer to the photographic surface of the element.
There is still a need, however, for dye compositions, particularly infrared dye compositions, that are stable in light and high humidity. There is particularly a need for stable infrared dye compositions which can be used as printing inks on imaging elements.
SUMMARY OF THE INVENTION
This invention provides a latex composition comprising water as a continuous phase and, as the dispersed phase, hydrophobic polymer particles having associated therewith an infrared polymethine dye having covalently bonded thereto a phenylenediamine moiety. It further provides a process for associating dye with polymer particles in a latex composition comprising the steps of:
(1) forming a dye solution by dissolving a polymethine dye having covalently bonded thereto a phenylenediamine moiety in a water miscible or immiscible organic solvent,
(2) forming a latex by dispersing hydrophobic polymer particles in an aqueous continuous phase,
(3) blending the latex with the dye solution, and
(4) loading of the polymer particles by removing the organic solvent, thereby forming a latex having the polymethine dye associated therewith.
This invention provides dye compositions which are very stable in light, high humidity, and other oxidative conditions. The dyes are low cost and they may be sensitive to both infrared and visible light. The dye compositions are particularly useful to print information on imaging elements. They may be used on the imaging layer side of the element or on the back side of the element.
DETAILED DESCRIPTION OF THE INVENTION
The infrared light-absorbing dye utilized in this invention is a polymethine (cyanine) dye having covalently bonded thereto a phenylenediamine moiety, and more preferably covalently bonded thereto at least two phenylenediamine moieties. The phenylenediamine moiety in the light-absorbing dye acts as a stabilizer. In one embodiment the phenylenediamine moiety is conjugated to the chromophore of the dye. Preferably the phenylenediamine moiety is a para-phenylenediamine moiety. It is also preferred that the phenylenediamine moiety contains an alkyl or phenyl substituent group. As used herein, an infrared-absorbing dye has substantial light absorptivity in the range between about 700 nm and about 1200 nm.
In one embodiment the infrared light-absorbing polymethine dyes may be represented by the following Formula (I):
X
1
, X
2
, and X
3
each independently represents hydrogen, halogen, cyano, an alkyl group having 1 to 12 carbon atoms (more preferably 1 to 6 carbon atoms), a cycloalkyl group having 5 to 10 carbon atoms in the carbocyclic ring, an aryl group having 6 to 10 carbon atoms in the carbocyclic ring, or any two of said X
1
, X
2
, and X
3
may be joined together to complete a 5- to 7-membered carbocyclic or heterocyclic ring group. Preferably X
1
, X
2
, and X
3
are hydrogen. m is 1-3, and more preferably 1 or 2.
R independently represents hydrogen or a substituent with at least one such group being the phenylenediamine moiety group Ra. Preferably both R groups are Ra. Each of R
1
, R
2
, R
3
, R4, and R
5
independently represents an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms in the carbocyclic ring, an aryl group having 6 to 10 carbon atoms in the carbocyclic ring, or a heterocyclic or polymeric backbone group. R
1
and R
2
or R
3
and R
4
may be joi
Chen Huijuan D.
Wang Ruizheng
Williams Kevin W.
Eastman Kodak Company
Meeks Roberts Sarah
Sastri Satya
Wu David W.
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