Radiation imagery chemistry: process – composition – or product th – Color imaging process – Using identified radiation sensitive composition in the...
Reexamination Certificate
2002-10-11
2004-06-29
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
Using identified radiation sensitive composition in the...
C430S502000, C430S503000, C430S543000, C430S552000, C430S553000, C430S551000, C430S558000, C430S512000, C430S931000, C430S372000
Reexamination Certificate
active
06756189
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a colour photographic element containing one or more cyan dye-forming couplers, in particular one or more phenolic cyan dye-forming couplers, a UV absorber and a specific class of stabilizer.
BACKGROUND OF THE INVENTION
In any chromogenic photographic material it is desirable that the dyes 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. It is important that the formed photographic images should be resistant towards fading due to heat, humidity and light. The coupler should produce a dye efficiently in the dye-forming reaction during photographic development, it must be easily dispersible, and must itself be resistant towards the effect of light heat and humidity. This is very difficult to achieve. There is still a need for cyan dye-forming couplers providing dyes which are stable to the deleterious effects of heat humidity and light.
Cyan dye-forming couplers of the general structure described in this invention are well known, for example as described in U.S. Pat. Nos. 2,367,531, 2,423,730, 2,474,293, 2,772,161, 2,772,162, 2,895,826, 2,920,961, 3,002,836, 3,034,892, 3,041,236, 3,466,622, 3,476,563, 3,552,962, 3,758,308, 3,779,763, 3,839,044, 3,880,661, 3,998,642, 4,333,999, 4,883,746, 4,990,436, 4,960,685, 5,476,757 and 5,614,357, UK Patent No. 2,070,000, French Patent Nos. 1,478,188 and 1,479,043, European Patent Application Nos. 0 544 322, 0 556 700, 0 556 777, 0 565 096, 0 570 006 and 0 574 948, DE patent application No. 197 01 869 and “Farbkuppler-eine Literature Übersicht,” published in Agfa Mitteilungen, Band III, pp. 156-175 (1961).
The use of cyclic bisphenol phosphate or phosphonate esters to improve the stability of cyan image dyes is shown in JP 02008839, in EP-A-1 197 798 and in U.S. Pat. Nos. 4,749,645 and 6,004,738. In the latter the cyclic bisphenol phosphonate esters are combined with phenolic coupler solvents to provide the required dye stability derived from the cyan couplers. The use of a cyclic silicon-blocked bisphenol to improve the stability for cyan dyes has been described in EP-A-1 191 398.
It is well-known that the spectral characteristics of the image dyes from these couplers can be manipulated by incorporating different functional groups into the molecular structure of the coupler and that the environment in which the dye is situated can also influence the hue of the dye. The use of certain solvents, like phenolic coupler solvents, can shift the dye absorption band to desirable longer wavelengths, as described in U.S. Pat. No. 5,376,519 and JP 59171953. One disadvantage of the use of these phenolic coupler solvents is that the resultant image is prone to thermally-induced increases in density, which is the result of morphological changes to the image structure which increase the covering power of the dye. Another disadvantage of these phenolic coupler solvents is their high viscosity which requires the use of an auxiliary organic solvent to enable the formation of small droplets (<0.25 micrometers in diameter) during homogenisation of the coupler dispersions during manufacture.
The use of benzotriazole UV absorbers for improving dye stability (especially light stability) of phenolic cyan couplers is well known, as shown by the following: U.S. Pat. Nos. 4,820,614, 5,084,375, 5,047,314 and EP-A-0 271 005. However, none of these describes a cyan coupler in combination with a UV absorber and bisphenol derivative (such as a cyclic phosphonate, or a silicon- or boron-blocked compound).
Dispersions with small droplets have many desirable properties, for example, reduced propensity to crystal formation, increased efficiency of the dye-forming reaction during development and improved resistance to abrasion of the final coating. However when an auxiliary organic solvent is used in the preparation of small droplet dispersions this solvent has to be removed before coating, usually by evaporation or by washing. It takes a long time to remove the auxiliary solvent and this is costly in time and equipment. In addition, with ever-increasing environmental concerns, reducing the amount of auxiliary organic solvent used in dispersions has been of paramount importance. Alternative methods for providing dispersions with small droplets without auxiliary solvent are to increase the homogenisation temperature, pressure or even to re-homogenise the dispersion, all of which are costly. Another alternative is to blend the phenolic coupler solvent with another high boiling solvent of lower viscosity, which affects, however, the desirable hue and stability properties of the coupler.
PROBLEM TO BE SOLVED BY THE INVENTION
There is still a need to provide a photographic element containing a dispersion of one or more cyan dye-forming couplers, which can provide further improved light and dark stability under normal storage conditions and high reactivity for formation of dye with oxidized colour developing agent.
SUMMARY OF THE INVENTION
The invention provides a photographic element comprising at least one light-sensitive silver halide emulsion layer having associated therewith at least one cyan dye-forming coupler, a UV absorber and a stabilizer of formula (I)
wherein
Y is phosphorous, silicon or boron;
R
1
and R
1
are independently selected from an unsubstituted or substituted alkyl, aryl, alkoxy, aryloxy group or a substituted amino group;
n is 0 or 1;
provided also that when
(a) Y is phosphorous, n is 1 and R
1
is oxygen (═O);
(b) Y is silicon, n is 1 and R
1
and/or R
1
may also be hydrogen, or
R
1
and R
1
may combine to complete a 5-10 membered heterocyclic ring which may contain, in addition to Y, one or more heteroatoms selected from nitrogen, oxygen and sulfur, which ring is unsubstituted or substituted; and
(c) Y is boron, n is 0;
each Z independently represents the atoms necessary to complete a substituted or unsubstituted arene or heteroaromatic ring system; and
X is a single bond or a linking group having an 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
This invention allows for improved light and dark stability in a photographic element without degradation in hue or reactivity of the dyes therein by the use of a combination of one or more cyan dye-forming couplers, a UV absorber and a cyclic phosphonate or silicon- or boron-blocked stabilizer.
DETAILED DESCRIPTION OF THE INVENTION
The invention is as described in the Summary of the Invention and relates to a photographic element containing at least one cyan dye-forming coupler combined with a UV absorber and a stabilizer, which enables there to be minimization of the amounts of coupler and silver necessary to achieve good photographic images, improved light stability and good thermal stability for album keeping.
As used herein and throughout the specification unless where specifically stated otherwise, the term “alkyl” refers to an unsaturated or saturated, straight or branched chain alkyl group, including alkeny
Clarke David
Gibson Danuta
Leyshon Llewellyn J.
Eastman Kodak Company
Kluegel Arthur E.
Letscher Geraldine
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