Radiation imagery chemistry: process – composition – or product th – Color imaging process – Using identified radiation sensitive composition in the...
Reexamination Certificate
2000-02-22
2001-03-27
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
Using identified radiation sensitive composition in the...
C430S462000
Reexamination Certificate
active
06207359
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a method for reducing dye stain in photographic elements. It also relates to a photographic element containing a photobleachable compound.
BACKGROUND OF THE INVENTION
Sensitizing dyes are added to photographic emulsions in order to impart spectral sensitivity beyond the intrinsic absorption range of silver halide. Sensitizing dyes are compounds that absorb light at wavelengths ranging from the near UV (ca. 400 nm) to the infrared (ca. 850 nm). Light that is absorbed by said sensitizing dyes results in electron injection into the conduction band of the silver halide, and ultimately in the formation of a latent image. In this way, the spectral response of photographic emulsions is extended to the spectral region covered by the absorption of the dye.
When used to impart spectral sensitivity to a photographic silver halide grains, the sensitizing dyes are usually removed during the processing steps (developing, fixing, and washing). The current trend is towards decreasing these processing times, since this has the advantage of reducing the amount of effluents. However, removal of the sensitizing dyes is often less efficient with shorter processing times. Residual sensitizing dyes, which remain in the emulsions after processing, cause unwanted coloration (dye stain) of the photographic material. In addition, some sensitizing dyes have a high propensity towards aggregation and/or have poor water solubility and as a result would require excessive processing times for complete removal.
SUMMARY OF THE INVENTION
It is desirable to find a method for reducing dye stain of an exposed and processed photographic material without affecting the image dye.
This objective is achieved by the present invention which provides a method for reducing dye stain of an exposed photographic element, said element comprising a support having thereon at least one image-forming layer containing a photobleachable dye, the method comprising processing the element, and exposing the processed element, in presence of a N-oxyazinium, to radiation that can be absorbed either by the photobleachable dye or by the N-oxyazinium.
The method involves photochemically bleaching the dyes by photoreactions of the dyes with N-oxyazinium compounds.
This invention provides a photobleaching method that can be advantageously carried out for a wide variety of photobleachable sensitizing dyes.
DETAILED DESCRIPTION OF THE INVENTION
When reference in this application is made to a particular group, unless otherwise specifically stated, the group may itself be unsubstituted or substituted with one or more substituents (up to the maximum possible number). For example, “alkyl” group refers to a substituted or unsubstituted alkyl group, while “aryl” refers to a substituted or unsubstituted aryl (with up to six substituents). The substituent may be itself substituted or unsubstituted.
Generally, unless otherwise specifically stated, substituents include any substituents, whether substituted or unsubstituted, which do not destroy properties necessary for the photographic utility. Examples of substituents include known substituents, such as: halogen, for example, chloro, fluoro, bromo, iodo; alkoxy, particularly those “lower alkyl” (that is, with 1 to 6 carbon atoms, for example, methoxy, ethoxy; substituted or unsubstituted alkyl, particularly lower alkyl (for example, methyl, trifluoromethyl); thioalkyl (for example, methylthio or ethylthio), particularly either of those with 1 to 6 carbon atoms; substituted and unsubstituted aryl, particularly those having from 6 to 20 carbon atoms (for example, phenyl); and substituted or unsubstituted heteroaryl, particularly those having a 5 or 6-membered ring containing 1 to 3 heteroatoms selected from N, O, or S (for example, pyridyl, thienyl, furyl, pyrrolyl); acid or acid salt groups such as any of those described below; and others known in the art. Alkyl substituents may specifically include “lower alkyl” (that is, having 1-6 carbon atoms), for example, methyl, ethyl, and the like. Further, with regard to any alkyl group or alkylene group, it will be understood that these can be branched or unbranched and include ring structures.
In the scope of the invention, the N-oxyazinium compound is an N-oxy-N-heterocyclic compound having from 5 to 14 nuclear carbon atoms in the heterocycle such as a pyridinium, diazinium, or triazinium nucleus. The N-oxyazinium compound can include one or more aromatic rings, typically carbocyclic aromatic rings, fused with the N-oxy-N-heterocyclic compound, including quinolinium, isoquinolinium, benzodiazinium, and naphthodiazinium. Any convenient charge balancing counter-ion can be employed to complete the N-oxyazinium compounds. The oxy group (—O—R
1
) of the N-oxyazinium compound which quaternizes the ring nitrogen atom of the azinium nucleus can be selected from among a variety of synthetically convenient oxy groups. The group R
1
can, for example, be an alkyl group such as methyl, ethyl, butyl, benzyl, an aralkyl group (e.g., benzyl or phenethyl) and a sulfoalkyl group (e.g., sulfomethyl). The group R
1
can be an aryl group such as a phenyl group. In another form R
1
can be an acyl group, such as an —C(O)—R
3
group, where R
3
is an alkyl and aryl groups such as phenyl or naphthyl, tolyl, xylyl, etc. When R
1
is an alkyl group, it typically contains from 1 to 18 carbon atoms, when R
1
is an aryl group, it typically contains from 6 to 18 carbon atoms.
Illustrative examples of useful N-oxyazinium compounds are shown by the formulae below:
wherein R
1
represents alkyl group of 1-12 carbons, or alkyl group substituted with one or more groups selected from the group consisting of acyloxy, alkoxy, aryloxy, alkylthio, arylthio, alkylsulfonyl, thiocyano, cyano, halogen, alkoxycarbonyl, aryloxycarbonyl, acetyl, aroyl, alkylaminocarbonyl, arylaminicarbonyl, alkylaminocarbonyloxy, arylaminocarbonyloxy, acylamino, carboxy, sulfo, trihalomethyl, alkyl, aryl, heteroaryl, alkylureido, arylureido, succinimido, and phthalimido substituent; aryl group, or acyl group; R
2
, R
22
or R
6
represents independently hydrogen, an alkyl group of 1-12 carbons, an aryl or heteroaryl group, unsubstituted or substituted with one or more substituents selected from the group consisting of an acyloxy, alkoxy, aryloxy, alkylthio, arylthio, alkylsulfonyl, thiocyano, cyano, halogen, alkoxycarbonyl, aryloxycarbonyl, acetyl, aroyl, alkylaminocarbonyl, arylaminicarbonyl, alkylaminocarbonyloxy, arylaminocarbonyloxy, acylamino, carboxy, sulfo, trihalomethyl, alkyl, aryl, heteroaryl, alkylureido, arylureido, succinimido and phthalimido substituent, or an acyloxy, hydroxy, alkoxy, aryloxy, alkylthio, arylthio, alkylsulfonyl, thiocyano, cyano, halogen, alkoxycarbonyl, aryloxycarbonyl, acetyl, aroyl, alkylaminocarbonyl, arylaminicarbonyl, alkylaminocarbonyloxy, arylaminocarbonyloxy, acylamino, amino, alkylamino, arylamino, carboxy, sulfo, trihalomethyl, alkyl, aryl, heteroaryl, alkylureido, arylureido, succinimido, phthalimido group, —CO—R
3
wherein R
3
is an alkyl or an aryl group, or —(CH═CH)
m
—R
4
wherein R
4
is an aryl or heterocyclic group; m is 1 or 2 ; Y is selected from the group consisting of S, O, Se, —C(R
1
)
2
, and —NR
1
; X is a divalent linking group selected from a group consisting of substituted or unsubstituted methylenes, (—CR
5
R
7
—)
n
and [(—CR
5
R
7
)
n
—X
1
—(CR
5
R
7
—)
P
] wherein R
5
or R
7
are independently hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl group, n and p are from 1-12, X
1
is aryl or heteroaryl nuclei, carbonyl, sulfo, thio, oxy; and Z is an alkylidene group.
In the scope of the invention, each of the above formulae can comprise one or more R
2
, R
22
or R
6
group.
Useful N-oxyazinium compounds can also be represented by the following formula
wherein A
+
is the N-oxyazinium moiety. The linking alkyl chain can have additional substituents, e.g., ether, ester, amide, etc.
According to one embodiment, the N-oxyazinium compound is a compou
Craver Mary E.
Farid Samir Y.
Goswami Ramanuj
Mangus John M.
Eastman Kodak Company
Le Hoa Van
Rice Edith A.
LandOfFree
Method for reducing the dye stain in photographic elements does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for reducing the dye stain in photographic elements, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for reducing the dye stain in photographic elements will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2459693