Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified radiation sensitive composition with color...
Reexamination Certificate
2001-08-30
2002-07-02
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified radiation sensitive composition with color...
C430S556000, C430S557000, C430S546000, C430S631000
Reexamination Certificate
active
06413707
ABSTRACT:
FIELD OF INVENTION
This invention relates to silver halide color photographic materials. More particularly, it relates to color photographic materials which contain yellow dye-forming couplers in combination with certain non-imaging compounds which give rise to images which have high stability towards fading by light.
BACKGROUND OF THE INVENTION
In a silver halide photographic element, a color image is formed when the element is exposed to light and then subjected to color development with a primary aromatic amine developer. Color development results in imagewise reduction of silver halide and production of oxidized developer. Oxidized developer reacts with one or more incorporated dye-forming couplers to form an imagewise distribution of dye.
In any polychromatic chromogenic photographic material it is desirable that the dyes so formed should have certain properties. For instance, the dyes should be bright in color with very little secondary absorption so that good color reproducibility is obtained. For yellow dyes in particular, color purity is enhanced by ensuring that the absorption maximum of the dye is well separated from that of the magenta dye and hence, yellow dyes that absorb at shorter wavelengths are advantageous. Acetanilide-based yellow dye-forming couplers have been found to provide desirable hues. The dyes that are formed by any color coupler during processing have a tendency to fade over times as a result of exposure to light, heat, humidity and oxygen resulting in a deterioration of the original recorded image. It is therefore highly desirable that the yellow dyes should be resistant towards fading by heat, humidity and light.
Acetanilide-based yellow dye-forming couplers of the general structures described in this invention are well known in the photographic art. Techniques are known in the art for providing resistance to light fade of such photographic yellow dyes. Compounds which have been disclosed as light stabilizers for yellow image dyes include substituted phenolic and blocked phenolic compounds including; heterocyclic phosphorous materials (U.S. Pat. No. 4,749,645), phenolic thiane derivatives (EP 0 310 551), substituted and blocked bisphenols (UK 1,267,287, U.S. Pat. No. 4,782,011, DE 4,307,439, DE 4,307,439, DE 4,320,828, EP 0 508 398, EP 0 538 862, U.S. Pat. Nos. 5,294,530, 5,426,021, 5,441,855, 5,441,861, 5,466,569, 5,891,613, WO 91/008,515, U.S. Pat. Nos. 5,567,578, 5,284,742, 5,091,294, EP 0 310 552, U.S. Pat. No. 5,935,773). In addition, yellow dyes may also be stabilized against fading by light with the use of thiomorpholine dioxide compounds as described in copending, commonly assigned U.S. Ser. No. 09/483,396 filed Jan. 14, 2000, the disclosure of which is incorporated by reference herein. However, it is desirable to improve on the light stabilization of yellow dyes beyond that afforded with use of the above stabilizers.
Acetanilide-based yellow dyes can also be stabilized against light fade with the use of some polymeric stabilizers. Polymeric compounds which have been disclosed as light stabilizers for yellow image dyes include, for example, those described in U.S. Pat. Nos. 4,857,449; 5,001,045; 5,047,314; 5,055,386; 5,200,304; 5,242,788; 5,294,527, 5,558,980, 5,594,047, and 5,981,159. Various techniques have been disclosed for preparing photographic dispersions of yellow dye-forming couplers and latex polymers, e.g., as described in U.S. Pat. Nos. 5,594,047 and 5,558,980. However, dispersions of yellow dye-forming couplers and polymeric addenda coated in a photographic element, whether it be the use of polymer latex particles or low molecular weight organic solvent soluble polymers, have disadvantages. With respect to polymer latex particles, they can be difficult to clean in large-scale manufacturing. In photographic elements, density increases after thermal treatments are also caused by the use of high levels of latex polymers. With respect to the solvent soluble polymers, they can be difficult to dissolve in coupler dispersions without the use of a low-boiling water-immiscible solvent, such as ethyl acetate. This is environmentally unfavorable, and often requires the additional step of removing the solvent before it can be coated in large-scale manufacture of photographic materials.
Typically, the yellow dye-forming color coupler and polymeric light stabilizer are dispersed in gelatin or other colloidal binder. In the dry state the gelatin is hard and can easily transmit applied stress to the silver halide grains. This can result in an unwanted “fogging” of the emulsion, meaning that a latent image site is formed due to the transmitted stress and not due to exposure with light. This is typically referred to as “pressure fog”. Techniques are known in the art to reduced pressure sensitivity by addition of dispersions of organic solvents to photographic elements (U.S. Pat. Nos. 4,840,881 and 4,499,179). However, these organic solvents are not themselves capable of providing light stability, most often degrading light stability, and can be used at such high levels that other problems are encountered such as delamination between adjacent layers in the photographic element. Similarly, prior art discloses the use of low glass transition temperature polymer latex into coated photographic elements to reduce pressure sensitivity (U.S. Pat. Nos. 3,576,628 and 4,822,727). Additional art discloses the use of gelatin-grafted and case-hardened gelatin-grafted soft latex polymer particles in combination with certain sugar surfactants (U.S. Pat. Nos. 5,066,572, 5,426,020 and 5,393,650). However, these particles do not offer any protection from fading of yellow image dyes due to light. Some latex polymers can be formulated to provide both light stability and pressure fog protection, such as described in U.S. Pat. No. 5,981,159. These latex polymers have the disadvantages mentioned previously.
Yet another method of stabilizing yellow dyes to fading by light is to disperse the yellow dye forming couplers in solid coupler solvents, such as alkyl alcohols or dialkyl or diaryl phosphates, according to U.S. Pat. No. 5,405,736. Such approaches can be disadvantaged in that the solid coupler solvent may precipitate or may cause precipitation of the yellow dye forming coupler or other solid materials during storage of the dispersion, which could lead to defects in the manufacture of a photographic element. Therefore, it is desirable to provide alternative methods of providing stabilization of yellow dyes to the fading of light without the inherent difficulties associated with known techniques of light stabilization.
SUMMARY OF THE INVENTION
An objective of this invention is to provide photographic elements which exhibit exceptional yellow dye light stability, and which retain desirable properties derived from the use of acetanilide based yellow dye-forming couplers. A further objective of the invention is to provide reduced pressure sensitivity for photographic elements comprising acetanilide based yellow dye-forming couplers.
In accordance with one embodiment of the invention, a photographic element is disclosed comprising a silver halide emulsion layer having associated therewith an acetanilide based yellow dye forming coupler and a compound of the following Formula I:
wherein R
1
, R
2
and R
3
are each independently aromatic, cyclic, linear, or branched chained hydrocarbon groups. We have found that the objectives of the invention can be achieved with acetanilide-based couplers through the use of urethane compounds of Formula I as stabilizing addenda, particularly when used in combination with known substituted phenolic and/or thiomorpholine dioxide stabilizers. In addition to stabilizing properties, compounds of Formula I have organic solvent properties, and accordingly may be advantageously used partly or totally in place of conventional high boiling permanent and/or auxiliary organic coupler solvents to disperse the acetanilide-based couplers. Unexpected and substantial improvements in the light stability of the image dyes can be obtained, and, in acc
Honan James S.
Rosiek Thomas A.
Schroeder Kurt M.
Thomas Brian
Yacobucci Paul D.
Eastman Kodak Company
Jackson Andrew J.
Letscher Geraldine
LandOfFree
Photographic element with yellow dye-forming coupler and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photographic element with yellow dye-forming coupler and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photographic element with yellow dye-forming coupler and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2863800