Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified radiation sensitive composition with color...
Reexamination Certificate
2001-06-22
2002-10-22
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified radiation sensitive composition with color...
C430S543000, C430S546000
Reexamination Certificate
active
06468728
ABSTRACT:
The invention relates to a colour photographic material comprising a support, at least one light-sensitive silver halide emulsion layer and at least one colour coupler associated with said layer.
It is known that colour couplers can be added to colour photographic materials. Colour couplers are understood to be compounds which react with the oxidation product of the colour developer during the processing of the material and which thus form the image dye, the optical density of which is designated as the colour density. The desired colour density can be achieved by using a large amount of coupler.
Couplers are very expensive, however, since it is very costly to synthesise them in the purity which is necessary for photographic materials. Moreover, in the prior art no success has been achieved in obtaining the optimum colour density and a steep gradation simultaneously.
The underlying object of the present invention is thus to provide a material with which a high colour density is achieved with compounds which are inexpensive, i.e. which are not couplers, wherein the material is distinguished by a steep gradation.
Surprisingly, it has now been found that this object is achieved if colourless carbonimidosulphones are used in a colour photographic silver halide material which contains at least one colour coupler.
The present invention therefore relates to a colour photographic material comprising a support, at least one light-sensitive silver halide emulsion layer and at least one colour coupler associated with said layer, characterised in that the material contains at least one compound of formula
R
1
—SO
2
—NH—CO—R
2
(I)
wherein R
1
and R
2
denote organic radicals, the N atom can also be deprotonated and compound I is substantially colourless and does not couple to form coloured compounds during the processing of the material.
Due to its high acidity, the N atom can also exist in deprotonated form, and compound I can be a salt. It is then represented as follows:
R
1
—SO
2
—N
(−)
—CO—R
2
M
n
(+)
(Ia)
wherein M
(+)
is a monovalent cation, and can therefore also be a proton, and n is equal to 0 if R
1
or R
2
carry an excess positive charge, and n is otherwise equal to 1. Moreover, compound I is always to be understood below to include compound Ia.
The group between the radicals R
1
and R
2
is hereinafter called a carbonimido-sulphone group, and compounds of formula I are called carbonimidosulphones.
Coupling is defined as a reaction with the developer oxidation product during the processing of the material, particularly a reaction with the oxidation product of a para-phenylenediamine developer substance.
“Substantially colourless” means that the compound of formula I, in the amount used, has an optical density of 0.05 at most in the wavelength region of visible light due to its inherent coloration.
The preferred compounds I are those in which R
1
and R
2
are bonded via a C atom to the carbonimidosulphone group.
In one advantageous embodiment, R
1
and R
2
, independently of each other, are aryl, alkyl, cycloalkyl, aryl-substituted alkyl, alkyl-substituted aryl, alkenyl or cycloalkenyl groups, or a heterocycle, wherein these radicals can be substituted and can contain heteroatoms.
R
1
and R
2
preferably represent, independently of each other, an aryl, alkyl, cycloalkyl, aryl-substituted alkyl, alkyl-substituted aryl, alkenyl or cycloalkenyl group, wherein at least one of the R
1
or R
2
radicals comprises more than 5 C atoms.
R
1
most preferably denotes an unsubstituted or substituted phenyl ring, wherein one or two alkyl radicals, chlorine atoms, or acyl or ether radicals are advantageous as substituents of the phenyl ring in each case.
R
1
most advantageously denotes an unsubstituted, mono- or di-methyl-, mono- or di-chloro-, mono-acyl- or mono-ether-substituted phenyl ring.
R
2
most preferably denotes a long chain alkyl radical comprising at least 7 C atoms, a phenol ether-substituted alkyl radical, or a substituted phenyl, polymer, acrylic acid ester, benzoic acid ester or acyl radical, wherein the radical advantageously comprises at least 12 C atoms and most advantageously comprises at least 16 C atoms.
In another advantageous embodiment, R
2
denotes a fluorine-substituted alkyl radical, particularly a monofluoromethyl or perfluoroalkyl radical comprising 1 to 6 C atoms.
Examples of colour photographic materials which contain colour couplers include colour negative films, colour reversal films, colour positive films, colour photographic paper and colour reversal photographic paper. A review is given in Research Disclosure 37038 (1995) and in Research Disclosure 38957 (1996).
Photographic materials consist of a support on which at least one light-sensitive silver halide emulsion layer is deposited. Thin films and foils are particularly suitable as supports. A review of support materials and of the auxiliary layers which are deposited on the front and back thereof is given in Research Disclosure 37254, Part 1 (1995), page 285 and in Research Disclosure 38957, Part XV (1996), page 627.
Colour photographic materials usually contain at least one red-sensitive, at least one green-sensitive and at least one blue-sensitive silver halide emulsion layer, and optionally contain intermediate layers and protective layers also.
Depending on the type of photographic material, these layers may be arranged differently. This will be illustrated for the most important products:
Colour photographic films such as colour negative films and colour reversal films comprise, in the following sequence on their support: 2 or 3 red-sensitive, cyan coupling silver halide emulsion layers, 2 or 3 green-sensitive, magenta coupling silver halide emulsion layers, and 2 or 3 blue-sensitive, yellow coupling silver halide emulsion layers. The layers of identical spectral sensitivity differ as regards their photographic speed, wherein the less sensitive partial layers are generally disposed nearer the support than are the more highly sensitive partial layers.
A yellow filter layer is usually provided between the green-sensitive and blue-sensitive layers, to prevent blue light from reaching the layers underneath.
The options for different layer arrangements and their effects on photographic properties are described in J. Inf. Rec. Mats., 1994, Vol. 22, pages 183-193, and in Research Disclosure 38957, Part XI (1996), page 624.
Colour photographic paper, which as a rule is less sensitive to light than is colour photographic film, usually comprises the following layers on the support, in the following sequence: a blue-sensitive, yellow coupling silver halide emulsion layer, a green-sensitive, magenta coupling silver halide emulsion layer, and a red-sensitive, cyan coupling silver halide emulsion layer. The yellow filter layer can be omitted.
Departures from the number and arrangement of the light-sensitive layers may be effected in order to achieve defined results. For example, all the high-sensitivity layers may be combined to form a layer stack and all the low-sensitivity layers may be combined to form another layer stack in a photographic film, in order to increase the sensitivity (DE 25 30 645).
The essential constituents of the photographic emulsion layer are binders, silver halide grains and colour couplers.
Information on suitable binders is given in Research Disclosure 37254, Part 2 (1995), page 286, and in Research Disclosure 38957, Part II.A (1996), page 598.
Information on suitable silver halide emulsions, their production, ripening, stabilisation and spectral sensitisation, including suitable spectral sensitisers, is given in Research Disclosure 37254, Part 3 (1995), page 286, in Research Disclosure 37038, Part XV (1995), page 89, and in Research Disclosure 38957, Part V.A (1996), page 603.
Photographic materials which exhibit camera-sensitivity usually contain silver bromide-iodide emulsions, which may also optionally contain small proportions of silver chloride. Photographic copier materials contain either silver chloride-bromide emulsions comp
Agfa-Gevaert
Connolly Bove & Lodge & Hutz LLP
Letscher Geraldine
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