JPH08292534A - Stabilized peroxide bleaching solution and processing methodof photographic element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stability-improved and highly efficient hydrogen peroxide bleaching liquid and a photographic element processing method using it. SOLUTION: In a color photographic element processing method containing bleaching a color photographic element exposed and developed as an image by using a hydrogen peroxide bleaching liquid, the bleaching liquid is formed by containing a hydrogen peroxide bleacher, a chloride ion existing by at least a quantity of 0.35 mole/l, organic phosphonic acid or a first acid compound being its salt, 2-pyridine carboxylic acid or 2,6-pyridine caboxylic acid, polyamino carboxylic acid whose pH is 8 to 11 and which has at least single secondary amine or a second acid compound being either of these salts.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to the processing of color photographic elements. In particular, it relates to the use of a stabilized hydrogen peroxide bleaching solution comprising an amount of chloride ion and two separate sequestering acidic compounds.

[0002]

BACKGROUND OF THE INVENTION When processing silver halide photographic elements,
The developed silver is oxidized to a silver salt with a suitable bleaching agent. The oxidized silver is then removed from the element during the fixing process. The most common bleaching solutions contain a complex of ferric ion and various organic ligands. Most desirable in the photographic industry is to design a bleaching composition that is better suited to the environment and therefore it is desirable to avoid or reduce the use of ferric complex bleaching agents.

Peroxide bleaching solutions such as peroxides, persulfates, perborates, perphosphates, perhalogens, percarboxylic acids or percarbonate bleaches are alternatives to ferric complex bleaches. I will provide a. They are less expensive and have less chemical and biological demands on the environment as their by-products are less harmful. Persulfate bleaches have a small environmental impact but have the disadvantage of requiring the presence of a bleach accelerator because of their slow bleaching activity. The most common bleach accelerators are thiol compounds, which have a malodor.

Hydrogen peroxide-based bleaching solutions offer many environmental advantages over persulfate and ferric complex bleach solutions because hydrogen peroxide reacts and decomposes to produce water. .
As a result, U.S. Pat.
Many publications, including 454,224, 4,717,649, and WO-A-92 / 01972 describe hydrogen peroxide bleaching solutions.

In addition, WO-A-09 / 07300 and EP 0428101 A1 describe hydrogen peroxide compositions for bleaching high chloride emulsions.
These compositions contain up to 0.3 mol of chloride ions per liter of solution and have a pH range of 5-11. However, these particular bleaches produce vesicles within the treated element.

International Publication No. A-93 / 11459 describes a hydrogen peroxide bleaching solution containing two or more water-soluble sequestrants which complex with transition metals. These solutions appear to be suitable for use in low silver paper materials.

[0007]

Despite the efforts of researchers in the art, many problems include vesicles (ie, blisters resulting from oxygen evolution), poor bleaching efficiency, and solution instability. No hydrogen peroxide bleach has been commercialized. However, there remains a need for highly efficient hydrogen peroxide bleaches with improved stability.

[0008]

What is claimed is: 1. A method of processing a color photographic element comprising bleaching an imagewise exposed and developed color photographic element with a hydrogen peroxide bleaching solution, said solution comprising: Hydrogen oxide bleach, at least 0.35 mol /
chloride ion present in an amount of 1; a first acidic compound which is an organic phosphonic acid or a salt thereof; and pyridinecarboxylic acid or 2,6-pyridinedicarboxylic acid, pH 8 to 1.
A method for processing a color photographic element comprising a polyaminocarboxylic acid having at least one secondary amine in 1, or a secondary acidic compound which is either a salt thereof, has been used to solve the above problems. .

The invention also provides hydrogen peroxide bleach, chloride ions present in an amount of at least 0.35 mol / l,
A first acidic compound which is an organic phosphonic acid or a salt thereof,
And a pyridinecarboxylic acid or 2,6-pyridinedicarboxylic acid, a polyaminocarboxylic acid having at least one secondary amine at pH 8-11, or a salt thereof, a second acidic compound. Hydrogen peroxide bleach is also provided.

The bleaching solution of the invention offers all the advantages of vesicle-free, good efficiency and rapid bleaching, but in addition the solution of the invention has improved stability. That is, the hydrogen peroxide is considerably less deteriorated over a long period of time. Therefore, this solution has improved storability during transportation and storage. These advantages are achieved by including in the solution a combination of two different water-soluble acidic compounds, each known for a different use, such as chelation with ferric ion. However, they have not previously been used in combination as sequestrants to stabilize hydrogen peroxide bleach. Therefore, the discovery that the combination of these materials provided such effects in hydrogen peroxide bleach was unexpected.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The hydrogen peroxide bleaching solution of the present invention comprises:
These include, but are not limited to, hydrogen peroxide, alkali and alkaline earth salts of peroxides, or conventional hydrogen peroxide bleaches including compounds that release or produce hydrogen peroxide. Such hydrogen peroxide precursors are well known in the art and include, for example, perborates, perphosphates, percarbonates, percarboxylates, and hydrogen peroxide urea.
In addition, hydrogen peroxide can be created in situ by electrolysis of aqueous solutions.

Examples of peroxide bleaching solutions include those described in Research Disclosure (Issue 36544, pages 501-541, 1994).
, September). Research Disclosure is Kenneth Mason Publication Ltd., Dudley Hous
e, 12 North Street, Emsworth, Hampshire PO10 7DQ, E
Published by ngland (also Emsworth DesignI
nc., 121 West 19th Street, New York, NY 10011
Also available from). Hereinafter, this document is simply referred to as "Research Disclosure". Hydrogen peroxide is the preferred bleaching agent.

The amount of hydrogen peroxide (or its precursor) is generally at least 0.15 mol / l,
It is preferably from 15 to 5 mol / l. The optimum amount will depend on the type of photographic element being processed. For example, in the case of a color negative film containing a silver bromoiodide emulsion, a more preferable amount is 0.9 to 3 mol / l. The most preferred amount for silver bromoiodide emulsion is 1.45 to 2.0 mol / l. For motion picture print film, a more preferred amount is 0.15
~ 1 mol / l, the most preferred amount being 0.35-0.
6 mol / l. For photographic color papers the preferred amount will be 0.15 to 3 mol / l.

Chloride ions can be converted into simple inorganic salts such as
It can be provided to the bleaching solution as part of sodium chloride, potassium chloride, ammonium chloride and lithium chloride. Further, it can be provided as an organic complex such as tetraalkylammonium chloride. Preferred salts are sodium chloride and potassium chloride. The chloride ion concentration is at least 0.35 mol / l, preferably 0.35 to 2 mol / l, most preferably 0.45 to 1 mol / l.

The bleaching solution of the present invention is quite simple and has four essential ingredients: a peroxide bleaching agent, chloride ions, and two separate sequestering acidic compounds as defined below. A preferred but not essential component is a buffer. The bleaching solution of the present invention is alkaline and has a pH of 7-1.
It has a general pH range of 3 (pH 8-11 is preferred). Add a normal weak base or strong base to this pH
One or more suitable buffering agents, such as, but not limited to, sodium carbonate, potassium carbonate, sodium borate, potassium borate, sodium phosphate, calcium hydroxide, sodium silicate, β-alanine. Diacetic acid, arginine, asparagine, ethylenediamine, ethylenediaminetetraacetic acid, ethylenediaminedisuccinic acid, glycine, histidine, imidazole, isoleucine, leucine, methyliminodiacetic acid, nicotine, nitrilotriacetic acid, piperidine, proline, purine and pyrrolidine are included) Can be maintained by being. Sodium carbonate or potassium carbonate is preferred.

The first acidic compound can be one or more organic phosphonic acids or salts thereof. Generally, such compounds are represented by structural formula (I) or (I
Represented by I): R ₁ N (CH ₂ PO ₃ M ₂ ) ₂ (I) or R ₂ R ₃ C (PO ₃ M ₂ ) ₂ (II) wherein R ₁ is hydrogen and carbon number 1 To 12 substituted or unsubstituted alkyl groups (eg, methyl, hydroxymethyl, ethyl, isopropyl, t-butyl, hexyl, octyl, nonyl, decyl, benzyl, 4-methoxybenzyl, β-phenethyl, o-octamidobenzyl). Or β-phenethyl), a substituted or unsubstituted alkylaminoalkyl group (wherein the alkyl part of the group is defined as above, for example, methylaminomethyl or ethylaminoethyl), and has 1 to 12 carbon atoms. A substituted or unsubstituted alkoxyalkyl group (eg, methoxymethyl, methoxyethyl, propoxyethyl, benzyloxy, methoxy) Tylene methoxymethyl or t-butoxy), a substituted or unsubstituted cycloalkyl group having 5 to 10 carbon atoms (for example, cyclopentyl, cyclohexyl, cyclooctyl or 4-methylcyclohexyl), a substituted or unsubstituted C 6 to 10 carbon atom. Aryl group (eg, phenyl, xylyl, tolyl, naphthyl, p-methoxyphenyl or 4-hydroxyphenyl), or a substituted or unsubstituted 5 member having one or more nitrogen, oxygen or sulfur atoms in the ring other than carbon ~ 1
0-membered heterocyclic groups [eg pyridyl, pyrimidyl, pyrrolyldimethyl, pyrrolyldibutyl, benzothiazolimethyl, tetrahydroquinolylmethyl, 2-pyridinylmethyl, 4- (N-pyrrolidino) butyl or 2- (N
-Morpholino) ethyl].

R ₂ is hydrogen, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms (as described above), or 6 to 1 carbon atoms.
0 substituted or unsubstituted aryl groups (as described above),
A substituted or unsubstituted cycloalkyl group having 5 to 10 carbon atoms (as described above), a substituted or unsubstituted 5-membered to 10-membered heterocyclic group (as above), - PO ₃ M ₂ or -CH
R ₄ PO ₃ M ₂ .

R ₃ is hydrogen, hydroxyl, or 1 to 1 carbon atoms.
12 substituted or unsubstituted alkyls (as above),
Or a -PO ₃ M _2. R ₄ is hydrogen, hydroxyl, a substituted or unsubstituted alkyl having 1 to 12 carbon atoms (as mentioned above), or a -PO ₃ M _2. M is
A hydrogen atom or a water-soluble monovalent cation that imparts water solubility, such as an alkali metal ion (for example, sodium or potassium), or an ammonium ion, a pyridinium ion, a triethanolammonium ion, a triethylammonium ion, or a group readily apparent to those skilled in the art. Others. The two cations in each molecule need not be the same. Preferably M is hydrogen, sodium or potassium.

In the definition of a substituted monovalent group herein, useful substituents include, but are not limited to, alkyl groups, hydroxy, sulfo, carbonamido, sulfonamide, sulfamoyl, sulfonato, thioalkyl,
Alkylcarbonamide, alkylcarbamoyl, alkylsulfonamide, alkylsulfamoyl, carboxyl, amino, halo (eg, chloro, bromo), sulfono, or sulfoxo, alkoxy having 1 to 5 carbon atoms (straight or branched chain), -PO ₃ M _2, -CH ₂ P
O ₃ M _2, or includes a _{-N (CH 2 PO 3 M 2} ) 2, the alkyl groups in these groups (linear or branched) has 1 to 5 carbon atoms.

Typical phosphonic acids useful in the practice of the present invention include, but are not limited to, European Patent Application No. 04281.
01A1 (page 4) are included. Representative compounds are 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediamine-N, N, N ', N'-.
Tetramethylenephosphonic acid, nitrilo-N, N, N-trimethylenephosphonic acid, 1,2-cyclohexanediamine-N, N, N ', N'-tetramethylenephosphonic acid,
o-carboxyaniline-N, N-dimethylenephosphonic acid, propylamine-N, N-dimethylenephosphonic acid,
4- (N-pyrrolidino) butylamine-N, N-bis (methylenephosphonic acid), 1,3-diamine-2-propanol-N, N, N ', N'-tetramethylenephosphonic acid, 1,3-propane Diamine-N, N, N ', N'
-Tetramethylenephosphonic acid, 1,6-hexanediamine-N, N, N ', N'-tetramethylenephosphonic acid,
o-acetamidobenzylamine-N, N-dimethylenephosphonic acid, o-toluidine-N, N-dimethylenephosphonic acid, 2-pyridinylmethylamine-N, N-dimethylenephosphonic acid, 1-hydroxyethane- 1,1-diphosphonic acid, diethylenetriamine-N, N, N ',
N ", N" -penta (methylenephosphonic acid), 1-hydroxy-2-phenylethane-1,1-diphosphonic acid,
2-hydroxyethane-1,1-diphosphonic acid, 1-hydroxyethane-1,1,2-triphosphonic acid, 2-hydroxyethane-1,1,2-triphosphonic acid, ethane-1,1-diphosphonic acid , And ethane-1,2-diphosphonic acid or salts thereof.

Particularly useful primary acidic compounds are 1-hydroxyethylidene-1,1-diphosphonic acid, nitrilo-
N, N, N-trimethylenephosphonic acid, diethylenetriamine-N, N, N ′, N ″, N ″ -penta (methylenephosphonic acid), or salts thereof. The first compound is most preferred. The amount of organic phosphonic acid compound used in the practice of the present invention is at least 0.0005 mol / l.
And generally up to 0.03 mol / l. 0.0
025 to 0.012 mol / l is preferable.

The second acidic compound of the bleaching solution can be many of the compounds described below. In one aspect,
It is generally a compound comprising at least one carboxyl group and an aromatic nitrogen heterocycle. They are water-soluble, preferably biodegradable.

More specifically, this group of secondary acidic compounds includes substituted or unsubstituted 2-pyridinecarboxylic acids and substituted or unsubstituted 2,6-pyridinedicarboxylic acids (or the corresponding salts). included. Substituents that may be on the pyridinyl ring include substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, or substituted or unsubstituted aryl groups (as defined in Structural Formulas I-II above). , Hydroxy, nitro, sulfo, amino, carboxy, sulfamoyl, sulfonamide, phospho, halo, or ferric ion ternary complexation,
Other groups that do not interfere with stability, solubility or catalytic activity are included. These substituents can be the atomic groups necessary to form a 5-membered to 7-membered condensed ring between any positions of the pyridinyl nucleus.

Preferred acidic compounds of this type are represented by the structural formula:

[0025]

Embedded image

[Wherein R, R ', R ", and R'" are independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms (as defined above), carbon number 6-10 substituted or unsubstituted aryl groups (as defined above), substituted or unsubstituted cycloalkyl groups having 5-10 carbon atoms (as defined above), hydroxy, nitro, sulfo, amino, carboxy, sulfamoyl , Sulfonamide, phospho, or halo (eg, chloro or bromo), or any two of R, R ′, R ″ and R ′ ″ can be substituted or unsubstituted by condensation with the pyridinyl nucleus. Carbon atoms necessary to form a 5- to 7-membered ring of

The monovalent and divalent groups defining Structural Formulas III and IV can have substituents similar to the groups defined in Structural Formulas I-II above. M has the same definition as above. Preferably R, R ', R "and R"' are independently hydrogen, hydroxy or carboxy. The most preferred compounds are unsubstituted 2-pyridinecarboxylic acid and 2,6-pyridinedicarboxylic acid, or salts thereof.

In another embodiment, the second acidic compound has a pH between 8 and.
11 is a polyaminocarboxylic acid containing at least one secondary amino group and at least two carboxyl groups (polydentate), or their corresponding salts. Such acids can be bidentate, tridentate, tetradentate, pentadentate, and hexadentate ligands. These acids must be water soluble and are preferably biodegradable (defined below).

More specifically, but not exclusively, these compounds include alkylenediaminetetracarboxylic acids having at least one secondary nitrogen atom, alkylenediaminepolycarboxylic acids having at least one secondary nitrogen atom. Carboxylic acids are included. With respect to Structural Formulas (V)-(IX), representative useful classes of such acidic compounds are defined below, but it should be recognized that in practice the present invention is not limited to these ligands. is there.

Accordingly, these compounds can have any of the following structures:

[0031]

Embedded image

[Wherein R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are independently hydrogen, hydroxy, straight chain or branched chain, substituted or unsubstituted carbon number 1 to 5 alkyl groups (eg methyl, ethyl, propyl, isopropyl,
n-pentyl, t-butyl and 2-ethylpropyl),
A substituted or unsubstituted cycloalkyl group having 5 to 10 carbon atoms in the ring (for example, cyclopentyl, cyclohexyl, cycloheptyl, and 2,6-dimethylcyclohexyl), or a substituted or non-substituted alkyl group having 6 to 10 carbon atoms in the aromatic nucleus. A substituted aryl group (eg phenyl, naphthyl, tolyl and xylyl), M is as defined above, and W is a conjugated bond or a divalent substituted or unsubstituted aliphatic linking group (defined below). belongs to],

[0033]

Embedded image

[Wherein at least two of R ¹¹ , R ¹² and R ¹³ are carboxymethyl groups (or corresponding salts)]
And the third group is hydrogen],

[0035]

[Chemical 4]

[Wherein one of R ¹⁴ and R ¹⁵ is hydrogen, and the other is a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms (as defined above), substituted or unsubstituted carboxymethyl (Or the corresponding salt) or 2-carboxyethyl (or the corresponding salt), and R ¹⁶ , R ^17, R ¹⁸ and R ¹⁹ are independently hydrogen, substituted or unsubstituted C 1 to C 5 An alkyl group (as defined above), hydroxycarboxy, carboxymethylamino, or a substituted or unsubstituted carboxymethyl group (or corresponding salts), wherein one of R ¹⁶ , R ^17, R ¹⁸ and R ¹⁹ Are carboxy, carboxymethylamino, or substituted or unsubstituted carboxymethyl groups (or corresponding salts)],

[0037]

Embedded image

[In the formula, one of R ²⁰ and R ²¹ is hydrogen, and the other is a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms (as defined above), substituted or unsubstituted hydroxyethyl, A substituted or unsubstituted carboxymethyl or 2-carboxyethyl (or the corresponding salts),
M is as defined above, p and q are independently
0, 1 or 2, but the sum of p and q does not exceed 2], or

[0039]

[Chemical 6]

[In the formula, Z has 6 to 1 carbon atoms in the ring.
0 substituted or unsubstituted aryl groups (as defined above) or heterocycles having 5 to 7 carbon, nitrogen, sulfur and oxygen atoms in the ring (eg, furanyl, thiofuranyl, pyrrolyl, pyrazolyl, triazolyl, dithiolyl, Thiazolyl, oxazoyl, pyranyl, pyridyl,
Piperidinyl, pyrazinyl, triazinyl, oxazinyl, azepinyl, oxepinyl and thiapinyl), L is a divalent substituted or unsubstituted aliphatic bonding group (as defined above), and one of R ²² and R ²³ is hydrogen. And the other is a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms (same as the above definition), a substituted or unsubstituted carboxyalkyl group having 2 to 4 carbon atoms (for example, substituted or unsubstituted carboxymethyl Or carboxyethyl, or a corresponding salt), or a hydroxy-substituted carboxyalkyl having 2 to 4 carbon atoms (or a corresponding salt)
And r is 0 or 1].

The "divalent substituted or unsubstituted aliphatic bonding group" in the definitions of "W" and "L" above has 1 to 10 atoms.
Included are non-aromatic linking groups comprising one or more alkylene, cycloalkylene, oxy, thio, amino, or carbonyl groups forming a 6 chain. Such groups include, but are not limited to, alkylene, alkyleneoxyalkylene, alkylenecycloalkylene, alkylenethioalkylene, alkyleneaminoalkylene, alkylenecarbonyloxyalkylene, all of which may be substituted or unsubstituted. May also be linear or branched), and others readily apparent to one of ordinary skill in the art.

In the definition of "substituted or unsubstituted" monovalent and divalent groups of the above structure, "substituted" means that the group is one or more, for example, an alkyl group having 1 to 5 carbon atoms (direct Chain or branched), hydroxy, carboxy, sulfo, sulfonato, thioalkyl, alkylcarbonamide, alkylcarbamoyl, alkylsulfonamide, alkylsulfamoyl, carbonamide, sulfonamide,
Sulfamoyl, amino, halo (chloro or bromo, etc.), sulfono (-SO ₂ R) or sulfoxo [-
It means that a substituent such as S (O) R] (where R is a branched or straight chain alkyl group having 1 to 5 carbon atoms) is present.

Regarding the above structural formulas (V) to (IX),
The definitions of preferred groups are as follows: M is hydrogen, ammonium, lithium, sodium or potassium, R ^5, R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are independently hydrogen. , Hydroxy or methyl, W is a conjugated bond or a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms, one of R ¹⁴ and R ¹⁵ is carboxymethyl, and R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ are independently hydrogen, carboxymethyl or carboxy, R ²⁰
And one of R ²¹ is methyl or carboxymethyl, Z is 2-pyridyl or 2-imidazolyl, L is a substituted or unsubstituted alkylene having 1 to 3 carbon atoms, R ²² and R One of ²³ is 2-carboxyethyl or carboxymethyl, and r is
It is 1.

The more preferred second acidic compound is N, N-
It is ethylenediamine disuccinic acid, N, N-ethylenediamine diacetic acid, and N- (2-carboxyethyl) aspartic acid, or salts thereof. In addition to these specifically defined acids mentioned above, additional useful secondary acidic compounds, which have secondary amino groups at pH 8-11, are described in European Patent Application Publication No. 056
There is considerable literature, such as 7126, US Pat. Nos. 5,250,401 and 5,250,402.

The amount of the second acidic compound used in the practice of the present invention is at least 0.0005-0.05 mol / l. A preferred amount is 0.001 to 0.05 mol / l. Mixtures of each type of primary or secondary acidic compound can also be used if desired.

As used herein, the terms "biodegradable" or "biodegradable" refer to Organization for Economic Co
Test Guide by operation and Development (OECD)
Line 302B (Paris, 1981), `` Modified Zahn
-At least 80% degradation in the standard test protocol, also known as "Wellens Test". Color photographic elements processed using this invention can contain any of the conventional silver halide emulsions. They can be "high chloride" or "low chloride" emulsions, but preferably they are "high chloride" emulsions. Accordingly, other emulsions including but not limited to silver bromide, silver iodide, silver bromoiodide, silver chloroiodide, silver chlorobromide, silver bromochloroiodide and silver chlorobromoiodide are also useful. is there. A "high chloride" emulsion is at least 5 as the halide component in the emulsion grains.
Means having 0 mol% chloride. More preferred are those containing at least 90 mol% chloride.
By "low chloride" emulsion is meant one having less than 30 mol% chloride, with less than 100 mol% chloride being preferred. High chloride emulsions contain less than 5 mol% iodide, but preferred are iodide free.

For elements treated in accordance with the present invention, the silver coverage can be any suitable amount known in the art, eg, 10 g / m ² or less. Preferably this amount is 2 g / m 2, especially when using "high" chloride emulsions.
^{It is} less than ² (for example, 0.3 to 0.8 g / m ² ). The photographic elements processed in the practice of this invention can be single layer or multilayer color elements. Multilayer photographic elements generally contain dye image-forming units sensitive to each of the three primary regions of the visible spectrum. Each unit can be a single emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum. The layers of the color photographic element can be arranged in various orders as known in the art. In another format, emulsions sensitive to each of the three primary regions of the visible spectrum can be arranged as a single segment layer. These elements can also have other conventional layers such as, for example, filter layers, interlayers, subbing layers, overcoat layers, and other layers readily apparent to one of ordinary skill in the art. As with conventional supports, magnetic backings can be used.

The structure and construction of the elements, and suitable methods of processing the various types of elements are described in Research Disclosure above. All types of emulsions can be used in the element, including, but not limited to, thin tabular grain emulsions and positive or negative working emulsions. These elements can be either photographic film elements or paper elements.

The elements are generally exposed to suitable radiation to form a latent image and processed to form a visible dye image. For processing, reduce developable silver halide,
A color development step is included in the presence of a color developing agent that oxidizes the color developing agent. The oxidized color developing agent then reacts with the color forming coupler to form a dye. Color developers are well known and are described in many publications including Research Disclosure. In addition to color developing agents, color developers generally contain a buffer (eg, potassium carbonate), a sulfite, a chelating agent, a halide, and one or more antioxidants as preservatives. There are many types of antioxidants including, but not limited to, hydrazines and substituted or unsubstituted hydroxylamines. Substituted hydroxylamines mean, for example, those having one or more alkyl or aryl groups attached to the nitrogen atom. These alkyl or aryl groups can be substituted with sulfo, carboxy, hydroxy,
It can be further substituted with one or more groups such as alkoxy, and other groups known in the art that provide a solubilizing effect. Examples of such hydroxylamines include, for example, US Pat. Nos. 4,876,174 and 4,89.
2,804, 5,178,992 and 5,35
4,646. One particularly useful hydroxylamine is N-isopropyl-N-ethylsulfonic acid hydroxylamine, or salts thereof.

Development can also be carried out using any developer / enhancing agent solution known in the art, as described in US Pat. No. 5,324,624. Following development, the bleaching solution described herein is used. The bleaching and fixing steps can be performed in any suitable manner, as is known in the art. Bleaching and fixing can be followed by a final wash or stabilization step. Color prints and color films can be processed, for example, using a wide variety of processing protocols as described in Research Disclosure above, and in one or more of one or more of a bleaching, fixing, washing or stabilizing step, And finally the can include various combinations of drying. In addition, reversal processing includes the additional steps of black and white development, chemical fog, re-exposure and washing prior to color development.

The treatment according to the present invention can be carried out by using an ordinary deep tank holding treatment liquid. Alternatively, what is known in the art as a "low volume thin tank" processing system having a rack and tank or automatic tray design can be used. Such processing methods and apparatus are described, for example, in US Pat. No. 5,436,1.
No. 18, and the publications mentioned above.

[0052]

The following examples are intended to illustrate the practice of the present invention and are not intended to limit the invention thereto. Percentages are weight percentages, unless stated otherwise. Examples 1-2: Color papers with stabilized bleach.
The bleaching solution of the invention was evaluated for bleaching efficiency according to the invention. These were also evaluated for storage stability. Several comparative bleaches were evaluated similarly.

A sample of EKTACOLOR EDGE ™ photographic color paper was tested on a standard 1B sensitometer for HA-50.
And NP-11 filter, 0.3 Inconel and 3000
The step wedge test target was subjected to 1/10 seconds using a K color temperature lamp. These were then processed using the following protocol (under nitrogen). The bleaching efficiency was measured by changing the bleaching time.

45 seconds Development * 30 seconds Stop solution (1% v / v H ₂ SO ₄ ) 30 seconds Water wash 0-2 minutes Bleach 30 seconds Water wash 1 minute Fixing ** 2 minutes Water wash 5 minutes Dry

* The developer (per liter) is
It is a normal KDAK EKTACOLOR RA color developer. ** The fixer (per liter) was an aqueous solution of sodium metabisulfite (11.8 g) and ammonium thiosulfate (56.5%) and ammonium sulfite (4.
%) Solution (162 ml) and the pH was 6.5.

KDAK PHOTO-FLO ™ is a commercial rinse. Control A bleach was hydrogen peroxide (0.98 mol /
1, 3% w / w), potassium chloride (0.35 mol / l),
Contains potassium carbonate (0.025 mol / l), potassium bicarbonate (0.025 mol / l) and 1-hydroxyethylidene-1,1-diphosphonic acid (0.004 mol / l), potassium hydroxide The pH was adjusted to 10 with.

Control B bleach was hydrogen peroxide (0.98 mol / l, 3% w / w), potassium chloride (0.35 mol / l).
l), potassium carbonate (0.025 mol / l), potassium bicarbonate (0.025 mol / l) and 2-pyridinecarboxylic acid (0.035 mol / l), and adjusted to pH 10 with potassium hydroxide did. Control C bleach was hydrogen peroxide (0.98 mol / l, 3% w / w), potassium chloride (0.
35 mol / l), potassium carbonate (0.025 mol / l)
l), potassium bicarbonate (0.025 mol / l) and 2,
It contained 6-pyridinedicarboxylic acid (0.035 mol / l) and was adjusted to pH 10 with potassium hydroxide.

Control D bleach was the same as Control A except that the phosphonic acid was omitted. Example 1 The bleaching solution was hydrogen peroxide (0.98 mol / l, 3% w / w), potassium chloride (0.
35 mol / l), potassium carbonate (0.025 mol / l)
l), potassium bicarbonate (0.025 mol / l), 1-hydroxyethylidene-1,1-diphosphonic acid (0.00
4 mol / l) and 2-pyridinecarboxylic acid (0.035
Mol / l) and adjusted to pH 10 with potassium hydroxide.

Example 2 The bleaching solution was hydrogen peroxide (0.98 mol / l, 3% w / w), potassium chloride (0.35 mol / l).
l), potassium carbonate (0.025 mol / l), potassium bicarbonate (0.025 mol / l), 1-hydroxyethylidene-1,1-diphosphonic acid (0.004 mol / l) and 2,6 -Pyridine dicarboxylic acid (0.035 mol /
1) and adjusted to pH 10 with potassium hydroxide.

FIG. 1 shows the stability data for the control, Example 1 and Example 2 bleach. These solutions were stored at room temperature for several days.
After one regular day, samples of these solutions were evaluated for the amount of residual hydrogen peroxide. This evaluation was achieved electroanalytical by cyclic voltammetry using a dropping mercury electrode. Electrical analysis data for normal EG & E Princet
Recorded using an Applied Rsearch potentiostat / galvanostat model 273A. Results were plotted as relative peroxide concentration (%) versus time (days). As shown in FIG. 1, controls B, C and D were the same.

From these data it is clear that the control B, C and D bleaches decomposed over time and the control A bleach decomposed with a half-life of about 7 days. The bleaching solutions of Examples 1 and 2 of the present invention have greatly improved stability. Example 1 is about 2
It decomposed with a half-life of 1, indicating that Example 2 hardly decomposed after 50 days at room temperature. Thus, it is clear that the combination of phosphonic acid and pyridine carboxylate provides a synergistic improvement in bleach liquor stability over the use of each compound independently.

Residual silver (g
/ M ² ) was measured. Table I below shows the case of constant density exposure after 45 seconds. Also the normal KODAK EKATACOLOR
The results using the RA bleach-fix solution are also shown.

[0063]

[Table 1]

The results show that the Control B and C bleaches (containing only the second acid) did not give effective bleaching after 45 seconds. Control A bleach (containing only primary acid) gave no acceptable bleaching. However, as shown in FIG. 1, Control A bleach was not of acceptable stability after storage for 14 days at room temperature. The Example 1 bleach and Example 2 bleach demonstrated fairly good storage stability over the test period. No vesicles were noted for the use of the invention. These results are also 2 using the present invention.
It shows that it provided bleaching comparable to KODAK EKTACOLOR RA even after storage for 1 day.

Examples 3-5: Moss with stabilized bleaching solution
Processing of larch paper The bleaching solution of the invention was evaluated for bleaching efficiency according to the invention. They were also evaluated for stability. Several comparative bleaches were also evaluated. The bleaching solution is hydrogen peroxide (0.98 mol / l), potassium chloride (0.35 mol / l).
l), potassium carbonate (0.025 mol / l), potassium bicarbonate (0.025 mol / l) and the amount of sequestrant shown in Table II below, pH 1 with potassium hydroxide.
Adjusted to 0.

[0066]

[Table 2]

The bleach solutions were evaluated for long term stability. The molar concentration of peroxide bleach (mol / l) was determined electroanalytical by cyclic voltammetry with a dropping mercury electrode. Electrical analysis data for normal EG & E Pri
nceton Applied Rsearch potentiostat / galvanostat model 273A. These results over time are shown in Table III below. Each solution was normalized to 0.98 mol hydrogen peroxide per liter of solution before the first measurement.

[0068]

[Table 3]

The data in Table III show that the three bleaching solutions of the invention retained significant bleaching activity after storage at room temperature for 35 days. Controls FH (containing only polycarboxylic acid) degraded within hours. Control E, which contained only phosphonic acid, was more stable than the other controls, but degraded within 21 days. The bleaching composition of the present invention was also evaluated for bleaching activity after storage at room temperature for 21 days.

A sample of EKTACOLOR EDGE ™ photographic color paper was run on a standard 1B sensitometer for HA-50.
And NP-11 filter, 0.3 Inconel and 3000
The step wedge test target was subjected to 1/10 seconds using a K color temperature lamp. These were then processed using the following protocol (under nitrogen).

45 seconds Development * 30 seconds Stop solution (1% v / v H ₂ SO ₄ ) 30 seconds Washing with water 45 seconds Bleaching 30 seconds Washing with water 1 minute Fixing ** 2 minutes Washing with water 5 minutes Drying

* The developer (per liter) is
It is a normal KDAK EKTACOLOR RA color developer. ** The fixer (per liter) was an aqueous solution of sodium metabisulfite (11.8 g) and ammonium thiosulfate (56.5%) and ammonium sulfite (4.
%) Solution (162 ml) and the pH was 6.5.

KDAK PHOTO-FLO ™ is a commercial rinse. Residual silver (g / m
² ) was measured. Table IV below shows the case of constant density exposure after 45 seconds. The results obtained with the regular KODAK EKATACOLOR RA bleach-fix and control E bleach (both fresh) are also shown. Of course, KODAK EKATACOLOR RA
In the use of bleach-fix solutions, the fixing and prewash steps were omitted from the processing protocol.

[0074]

[Table 4]

These results show that no loss of bleaching performance was observed for the bleaching composition of the invention after storage for 3 weeks. In addition, these compositions bleached the above photographic elements more completely than the conventional RA-4 bleach-fix with freshly prepared. No vesicles were found in any of these bleaching compositions. The results of these experiments show that two specific acids in bleaching compositions [phosphonic acid and polyaminocarboxylic acid (with at least one secondary amine)].
Shows that stability is improved and there is no loss of bleaching performance over the use of the individual acids alone.

[Brief description of drawings]

FIG. 1 is a graph of the relative peroxide concentration of a bleaching solution of the present invention and a bleaching solution of the prior art with respect to storage time.

Claims (2)

[Claims] 1. A method of processing a color photographic element comprising bleaching an imagewise exposed and developed color photographic element with a hydrogen peroxide bleaching solution, said bleaching solution being a hydrogen peroxide bleaching solution. An agent, a chloride ion present in an amount of at least 0.35 mol / l, a first acidic compound which is an organic phosphonic acid or salt thereof,
And a second acidic compound which is either 2-pyridinecarboxylic acid or 2,6-pyridinedicarboxylic acid, a polyaminocarboxylic acid having at least one secondary amine at pH 8 to 11, or a salt thereof. A method of processing a color photographic element. 2. A hydrogen peroxide bleaching agent, a chloride ion present in an amount of at least 0.35 mol / l, a first acidic compound which is an organic phosphonic acid or a salt thereof,
And 2-pyridinecarboxylic acid or 2,6-pyridinedicarboxylic acid, a polyaminocarboxylic acid having at least one secondary amine at pH 8-11, or a salt thereof, a second acidic compound. Hydrogen peroxide bleaching solution consisting of.