Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified radiation sensitive composition with color...
Reexamination Certificate
2000-02-22
2002-04-23
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified radiation sensitive composition with color...
C430S510000, C430S517000
Reexamination Certificate
active
06376163
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a photobleachable dye composition. The present invention also relates to an imaging element containing the composition, and a method for photobleaching of a photographic element containing the composition.
BACKGROUND OF THE INVENTION
In the field of photography, it is known to provide photographic elements comprising filter or antihalation compositions to improve the resolution of photographic materials. These antihalation dye compositions can be in the emulsion layer, or preferably in a non-image forming auxiliary layer. Without these antihalation dye layers, radiation reaching the photographic emulsion layer would be reflected, and image sharpness would decrease. After the image-wise exposure of the photographic element, the antihalation dye composition is generally bleached during or after the processing. Thermally bleachable antihalation dye compositions are known. Photobleachable antihalation dye compositions and chemically bleachable antihalation dye compositions are also known wherein subsequent to the imaging and processing steps, the film could then be exposed to a suitable light source or chemicals to bleach the dye.
For example, U.S. Pat. No. 4,548,896 discloses an imagewise bleachable composition comprising a dye in reactive association with a mesoionic compound, the composition being bleached through exposure to radiation at a wavelengths between 200 and 1000 nm.
U.S. Pat. No. 3,745,009 discloses a bleachable dye wherein an N-oxy substituent is part of the dye chromophore. The synthesis of these dyes is usually complex. Further, these dyes need to be carefully handled. Due to their inherent bleachable ability, they are not light stable.
U.S. Pat. Nos. 4,743,528, 4,743,529, 4,743,530 and 4,743,531 disclose a polymerisable composition comprising an azinium activator, a photosensitizer, and an ethylenically unsaturated monomers.
EP 308274 discloses a photobleachable cyanine dye composition containing a borate salt. The technology appears to be useful with a very limited variety of bleachable dyes.
Many of the known bleaching methods suffer from one or more disadvantages. They are limited to either heat or light sensitivity or to the required numbers of steps for carrying out the bleaching. Some methods are also limited to the narrow number of useful dyes, or by the effort required for synthesizing the useful dye.
SUMMARY OF THE INVENTION
It is desirable to find a photobleachable composition that eliminates the drawbacks of the known photobleachable compositions.
It is also desirable to provide a photographic element containing a photobleachable composition and a method for bleaching the photographic element containing the photobleachable composition.
These and other objects are achieved by the present invention, which provides a visible-light sensitive photobleachable dye composition, substantially free of polymerisable monomer, comprising a photobleachable dye and an N-oxyazinium compound.
The invention also relates to an imaging element comprising a support having thereon at least one image forming layer, and at least one non-image forming layer wherein the element further comprises a visible-light sensitive photobleachable composition containing a photobleachable dye and an N-oxyazinium compound.
Then, the invention relates to a method for bleaching a photographic element comprising a support having thereon at least one image forming layer, at least one non-image forming layer comprising a visible-light sensitive photobleachable composition containing a photobleachable dye and an N-oxyazinium compound, the method comprising:
exposing and processing the photographic element, and exposing the exposed and processed element, to radiation that can be absorbed either by the photobleachable dye or by the N-oxyazinium compound.
The method involves photochemically bleaching the photobleachable dyes relying on photoreactions of the photobleachable dye with an N-oxyazinium compound.
This invention provides a photobleaching method that can be advantageously carried out for a wide variety of photobleachable dyes such as sensitizing dyes, filter dyes, image dyes, infrared dyes or antihalation dyes. In addition, in the present invention, the photobleachable dye and the N-oxyazinium are distinct entities. As a result, the dyes can be easily handled in light, since the bleaching effect occurs only in the presence of the N-oxyazinium.
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, such as aralkyl group or sulfoalkyl group while “aryl” group refers to a substituted or unsubstituted aryl group (with up to six substituents) such as alkaryl or sulfoaryl group. 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 a heterocyclic nucleus, 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, phenanthridium and naphthodiazinium. Any convenient charge balancing counter-ion can be employed to complete the N-oxyazinium compounds. The oxy group (—O—R,) 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, alkylaminocarbonyloxy, acylamino, carboxy, sulfo, trihalomethyl, alkyl, aryl, h
Farid Samir Y.
Goswami Ramanuj
Gould Ian R.
Perry Robert J.
Williams Kevin W.
Le Hoa Van
Rice Edith A.
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