Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified radiation sensitive composition with color...
Reexamination Certificate
1999-09-01
2001-02-20
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified radiation sensitive composition with color...
C430S505000, C430S544000, C430S957000
Reexamination Certificate
active
06190853
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to silver halide-based photographic elements containing yellow dye-forming couplers, hereinafter called yellow couplers. In particular, the invention relates to elements with yellow couplers with an indazole coupling-off group providing images with improved sharpness for use with silver halide based photographic emulsions.
BACKGROUND OF THE INVENTION
Photographic layers sensitive to blue light for use in a color photographic material typically contain a yellow coupler which, on reaction with an oxidised p-phenylenediamine developer, forms a yellow dye. Generally commercially available photographic films contain pivaloyl or benzoyl acetanilide yellow couplers. With such couplers a person skilled in the art will be aware that there will be usually have to be a compromise in choice of coupler between coupler activity as measured for example by contrast on the one hand and dye stability on the other.
It will be appreciated that it is a desirable feature of photographic systems to produce images which are not only correct in color, density and contrast and with satisfactory dye stability but which are also visually sharp. Currently this can be achieved by the use of a combination of an image coupler with a development inhibitor releasing coupler (DIR), from which inhibitor is released directly as a coupling-off group, or with a development inhibitor anchiameric releasing coupler (DIAR), from which inhibitor is released from a coupling-off group after a time delay which results from an additional reaction step. This delay permits control over such parameters as time of release, rate of release and rate of diffusion of the coupling-off group.
It would be advantageous to obtain visually sharp images, while retaining the other desired characteristics, by the use of a single coupler. The criterion for the success of this would be that the inhibitor fragment would be a mild inhibitor and that the coupler would have good activity. The two aspects would need to be carefully balanced to achieve the desired results giving good sensitometry for yellow image couplers, and in particular adequate activity for image formation, sufficient inhibition to give a noticeable improvement in image sharpness with no deleterious effects on dye stability and especially dark/wet stability.
SUMMARY OF THE INVENTION
According to the present invention there is provided a photographic element comprising a light sensitive silver halide emulsion layer containing an image-dye-forming coupler of formula (I):
wherein:
R is an alkyl, aryl, alkoxy or heterocyclic group;
R
1
-R
5
are hydrogen or an independently selected substituent, provided that R
1
and R
2
, R
2
and R
3
, R
3
and R
4
and R
4
and R
5
may represent fused cyclic groups;
Ind is an indazole of formula (II):
wherein
Ind is linked directly to the coupler via a ring nitrogen atom (N
a
or N
b
); and
V, W, X, Y and Z are the same or different and are hydrogen or a substituent;
provided that the sum of the Hammett sigma para values of V, W, X, Y and Z is equal to or greater than 0.4.
The present invention also includes the coupler compound of formula (I).
The elements of the invention exhibit improved sharpness and other desirable image qualities.
DETAILED DESCRIPTION OF THE INVENTION
The invention is as generally described in the Summary of the Invention. Substituent R is an alkyl, aryl, alkoxy or heterocyclic group. In particular, R is selected from an alkyl (including alkenyl), aryl, alkoxy or heterocyclic group optionally substituted with one or more coupler-modifying functional groups and is typically alkyl, alkoxy, phenyl, naphthyl, pyridyl or dioxanyl, preferably alkyl, alkoxy or phenyl, especially i-propyl, t-butyl, ethoxy or phenyl, optionally substituted with, for example, alkyl, alkoxy, chloro or alkylsulfamoyl.
Thus unsubstituted or substituted R may be selected from one of the following representative groups, without limitation thereto:
where R
1
-R
5
, are hydrogen or an independently selected substituent, provided that R
1
and R
2
, R
2
and R
3
, R
3
and R
4
and R
4
and R
5
may represent fused cyclic groups. Suitably, one or more of R or R
1
-R
5
is selected from coupler-solubilizing groups, ballasting groups and dye hue-modifying groups. Photographic ballast groups are known in the art and comprise an organic group of such size and configuration so as to make the coupler molecule non-diffusible in a coated photographic element. Two or more couplers may be attached to the same ballast group or two or more ballasts may be attached to the same coupler. Generally the sum of the number of carbon atoms in one or more ballast groups is at least 10.
R
1
-R
5
may be selected from hydrogen or a substituent, preferably one that is non-deleterious to the coupling reaction between the coupler and the oxidized developer. Examples of suitable substituents are, but not limited to, halogen, R, RO, R
2
N, RHN, H
2
N, RS, RSO, RSO
2
NH, RSO
2
, RSO
2
O, ROOC, HOOC, RCOO, RNHCO, R
2
NCO, RNHCONH, RCONH, RNHSO
2
, R
2
NSO
2
, H
2
NSO
2
, RCO, NO
2
, CN, CF
3
, P(OR)
3
, PO(OR)
3
, where R is a group as above defined other than alkoxy. Substituents R
1
and R
2
, R
2
and R
3
, R
3
and R
4
and/or R
4
and R
5
may represent a fused cyclic group (e.g. R
1
and R
2
may represent the residue of a fused benzene or pyridine ring).
Preferably R
1
-R
5
are selected from hydrogen, halogen, or substituted or unsubstituted alkoxy, aryloxy, carboxy ester, alkyl- or aryl-sulfonyl, alkyl- or aryl-carbamoyl, alkyl- or aryl-sulfonamido, alkyl- or aryl-sulfamoyl and alkyl- or aryl-sulfonyloxy. More preferably there are present at least two substituents on the phenyl ring of the anilide portion of the coupler and it is especially preferred that at least one of these is a chloro or alkoxy group in the ortho position on the phenyl ring.
Some representative examples of the aryl group attached to the anilide portion of the coupler (I) are shown below but suitable compounds are not limited to this list.
Moreover any of the above substituents R
1
-R
5
, other than H and halogen, may be substituted with one or more of the same or different substituents of R
1
-R
5
as hereinabove defined, which may in turn be further substituted. Generally at least one of R
1
-R
5
is or contains a ballast group although such a group may alternatively or additionally be present in the R substituent or in the indazole coupling-off group.
A coupler-modifying group is a substituent which, by its presence in the coupler structure, influences the photographic or physical properties of the coupler or the dye derived from the coupler.
As used herein and throughout the specification the term alkyl refers to an unsaturated or saturated straight or branched chain alkyl group (including alkenyl) having 1-20 atoms and includes cycloalkyl having 3-8 carbon atoms.
Thus, unless otherwise specifically stated, substituent groups usable on molecules herein include any groups, whether substituted or unsubstituted, which do not destroy properties necessary for photographic utility. When the term “group” is applied to the identification of a substituent containing a substitutable hydrogen, it is intended to encompass not only the substituent's unsubstituted form, but also its form further substituted with any group or groups as herein mentioned. Suitably, the group may be halogen or may be bonded to the remainder of the molecule by an atom of carbon, silicon, oxygen, nitrogen, phosphorous, or sulfur. The substituent may be, for example, halogen, such as chlorine, bromine or fluorine; nitro; hydroxyl; cyano; carboxyl, or groups which may be further substituted, such as alkyl, including straight or branched chain alkyl, such as methyl, trifluoro-methyl, ethyl, t-butyl, 3-(2,4-di-t-pentylphenoxy) propyl, and tetradecyl; alkenyl, such as ethylene, 2-butene; alkoxy, such as methoxy, ethoxy, propoxy, butoxy, 2-methoxyethoxy, sec-butoxy, hexyloxy, 2-ethylhexyloxy, tetradecyloxy, 2-(2,4-di-t-pentyl-phenoxy)ethoxy, and 2-dodecyloxyethoxy; aryl such as phenyl, 4-
Eastman Kodak Company
Kluegel Arthur E.
Letscher Geraldine
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