Radiation imagery chemistry: process – composition – or product th – Color imaging process – Stabilizing
Reexamination Certificate
2001-08-21
2002-09-03
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
Stabilizing
C430S383000, C430S543000, C430S546000, C430S551000, C430S553000, C430S554000, C430S555000, C430S557000, C430S558000
Reexamination Certificate
active
06444412
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to conventional and to redox-amplified silver halide colour photographic materials and more particularly to such materials which contain a dye-forming coupler in combination with certain non-imaging compounds. The resulting dyes exhibit an exceptional combination of photographic properties, especially in regard to hue and stability. The application is related to UK application number 0023093.8 of even date herewith.
BACKGROUND OF THE INVENTION
In a silver halide photographic element, a colour image is formed when the element is exposed to light and then subjected to colour development, generally with a primary aromatic amine developer. Colour 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 colour, absorbing light in the appropriate spectral region, with very little secondary absorption so that good colour reproducibility is obtained. The dyes that are formed by any colour coupler during processing have a tendency to fade over time as a result of exposure to light, heat, humidity and oxygen. Since the three image dyes may not fade at the same rate, an apparent change in image colour may result. It is thus paramount that the formed photographic dye images should be resistant towards fading by heat, humidity and light.
When the dye images are formed in silver halide photographic materials from the combination of oxidized developer and an incorporated coupler, certain restrictions are placed on the properties of the coupler. For instance, the coupler should produce a dye which has the aforementioned desirable properties and the efficiency of the dye-forming reaction must be high. Additionally, the coupler must be easily dispersible, must itself be resistant towards the deleterious effects of light, heat and humidity and must have a low propensity to form fog.
It is well known in the art of coupler chemistry that when a functionality is incorporated into a molecule to achieve one of the aforementioned desirable properties (such as high dye light stability), quite often one or more of the other desirable properties of the photographically formed dye (such as its hue) is affected adversely. It is very difficult to obtain a coupler which manifests all or even most of the aforementioned desirable properties. For example, dyes formed by diacylaminophenolic cyan couplers, whilst exhibiting excellent resistance to fading by heat and humidity, are especially deficient in their ability to withstand the effects of light and their absorption bands tend to lie at shorter wavelengths than is desirable, particularly for colour paper applications.
It is known that the absorption characteristics of an image dye can be modified by the chemical environment in which the dye is situated. For example, U.S. Pat. Nos. 4,952,487 and 5,376,519 and JP 59171953 teach the use of certain phenolic coupler solvents to shift the dye absorption band to longer wavelengths. Additionally, the hue of the dye can also be manipulated by incorporating certain functionalities into the molecular structure of the coupler, and these techniques can also result in the enhancement of other features such as coupling reactivity or image dye light stability.
Another method of improving image dye light stability is by the incorporation of certain stabilizing addenda into the coupler dispersion. Such stabilizing addenda can be used alone or in combination. For example, U.S. Pat. No. 6,004,738 teaches that the aforementioned diacylaminophenolic cyan image dyes can be stabilized by the use of heterocyclic phosphorus derivatives of certain bis-phenols, especially when these are used in combination with phenolic coupler solvents. In particular, UK Application number 0023093.8 of even date herewith describes the selection of meta and/or para fluoro- and fluoroalkyl-substituted diacylaminophenolic cyan image-forming couplers for further improvement in light stability.
The use of the same phosphorus heterocycles to stabilize yellow image dyes against deterioration by light is taught in U.S. Pat. No. 4,749,645, while UK Patent No. 1,267,287 and U.S. Pat. No. 4,782,011 teach, respectively, the benefits of their unsubstituted parent bis-phenols and mono-blocked derivatives thereof as stabilizers of these dyes. Furthermore, EP-A-0 310 551 and EP-A-0 310 552 describe the use of phenolic antioxidants in combination with thiane derivatives and yellow dye-forming couplers for improved light stability.
U.S. Pat. Nos. 5,017,465 and 5,082,766 and German Published Patent Application DTOS 4,307,194 describe the use of certain cyclic sulfur and/or oxygen-containing stabilizers with pyrazoloazole magenta dye forming couplers to improve their image dye stability.
Nevertheless, there remains a continuing need to seek coupler formulations with improved performance because, quite often, one or more of the other desirable properties of the photographically formed dye (such as its hue) can be affected adversely by these artifices.
Heterocyclic silicon-blocked bis-phenols have been disclosed by S. D. Pastor in J. Org. Chem. 1984,49, 1927 and their use as stabilizers for plastics described in EP-A-0 114,148. The use of such compounds to stabilise dye-forming couplers has not been disclosed therein.
PROBLEM TO BE SOLVED BY THE INVENTION
The problem to be solved is the provision of a photographic element comprising a dye-forming formulation which provides an image dye of good hue and which exhibits exceptional stability against the effects of light without significant degradation of other photographic properties.
SUMMARY OF THE INVENTION
In accordance with the embodiment of the invention there is provided a photographic element comprising a light sensitive silver halide emulsion layer having associated therewith one or more dye-forming couplers and a stabilizer compound of formula (I):
wherein
R
1
and R
2
are independently selected from hydrogen or an unsubstituted or substituted alkyl, aryl, alkoxy, aryloxy or substituted amino group or may combine to complete a 5-10 membered heterocyclic ring which may contain in addition to the silicon atom one or more heteroatoms selected from nitrogen, oxygen and sulfur, which ring is unsubstituted or substituted;
each Z independently represents the atoms necessary to complete a substituted or unsubstituted arene or heteroaromatic ring system;
X is a single bond or a linking group having a single atom which connects the arene or heteroaromatic ring systems; or
X forms, together with substituents ortho to X on the arene or heteroaromatic ring systems, a fused unsubstituted or substituted 5-, 6- or 7-membered ring, which may contain one or two heteroatoms selected from nitrogen, oxygen and sulfur.
In another embodiment of the invention there is provided a multi-colour photographic element comprising a support bearing yellow, magenta and cyan image-dye-forming units comprising at least one blue-, green- or red-sensitive silver halide emulsion layer having associated therewith at least one yellow, magenta or cyan dye-forming coupler respectively, wherein the element is as herein described.
In yet another embodiment of the invention there is provided a process of forming an image in a photographic element as hereinbefore defined after the element has been imagewise exposed to light, comprising contacting the element, as herein described, with a colour developing agent.
ADVANTAGEOUS EFFECT OF THE INVENTION
The element of the invention provides an image dye of good hue, exhibiting exceptional stability against the effects of light, without significant degradation of other photographic properties.
DETAILED DESCRIPTION OF THE INVENTION
The combination of the invention is generally as described in the Summary of the Invention.
The stabilizer of the invent
Clarke David
Leyshon Llewellyn J.
Moore Christopher P.
Eastman Kodak Company
Kluegel Arthur E.
Letscher Geraldine
LandOfFree
Photographic element with 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 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 dye-forming coupler and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2901662