EP0447655A1 - Granulated photochemicals - Google Patents

Abstract

Photographic processing chemicals in the form of granules with an average particle diameter of 150 to 3000 µm, which contain a polymer with a molecular weight of 6,000,000 to 14,000,000 in an amount of 1 to 1000 mg / kg of granules, which consists of at least 80 mol% one or more of the monomers acrylamide, acrylic acid or cationic monomer, or mixtures of acrylamide and cationic or anionic monomer, are characterized by ease of manufacture, dust-free and free-flowing properties.

Description

The invention relates to granulated photo chemicals and a process for their production.

Photographic processing baths, e.g. Developmental, bleaching and fixing baths usually contain the required active ingredients in low concentrations and are therefore prepared by the user himself from water and chemical concentrates as well as, if necessary, other auxiliaries.

The concentrates should be dosed as simply as possible and should be largely dust-free. In addition, no unnecessarily high costs should arise for packaging and transport.

The liquid concentrates which are generally used in practice for the production of ready-to-use photographic baths have the advantage over the previously used, powdered products that no dust development and no solution problems occur. The concentrates have the disadvantages of the high proportion by weight and volume of water, as well as difficulties in disposing of the bulky packaging.

According to DE-OS 37 33 861 spray-dried or freeze-dried products which are intended to avoid these disadvantages, however, show a high level of dust.

Our own attempts to reduce the dust content by means of certain granulation processes were only partially successful. It was not possible to completely avoid the development of dust, and it was not possible to granulate all processing formulations.

The object of the invention is therefore to find means with which a larger spectrum of photographic processing chemicals can be granulated, the dust content should be further reduced. The granules should also dissolve in water in a short time.

It has now been found that small additions of a hydrophilic polymer to the solid components of photographic processing baths enable granulation with excellent results.

The invention therefore relates to photographic processing chemicals in the form of granules with an average particle diameter of 150 to 3000 microns, containing the necessary active ingredients and auxiliary substances, characterized in that the granules additionally contain a polymer having a molecular weight of 500,000 to 14,000,000 in one Amount from 1 to 1000 mg / kg of granules, preferably from 50 to 150 mg / kg of granules, containing at least 80 mol% of acrylamide, acrylic acid, cationic Monomer, or mixtures of acrylamide and cationic or anionic monomer.

Suitable cationic comonomers are, for example
N-vinylbenzyl-N, N, N-trimethylammonium chloride,
N-benzyl-N, N-dimethyl-N-vinylbenzylammonium chloride,
N, N, N-trihexyl-N-vinylbenzylammonium chloride,
N- (3-maleimidopropyl) -N, N, N-trimethylammonium chloride,
N-benzyl-N- (3-maleimidopropyl) -N, N-dimethylammonium chloride,
N-vinyloxycarbonylmethyl-N, N, N-trimethylammonium chloride,
N- (3-acrylamido-3,3-dimethylpropyl) -N, N, N-trimethylammonium methosulfate,
1,2-dimethyl-5-vinylpyridinium methosulfate,
N- (2-hydroxy-3-methacryloyloxypropyl) -N, N, N-trimethylammonium chloride,
N- (2-hydroxy-3-methacryloyloxypropyl) -N, N, N-trimethylammonium sulfate,
N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium iodide,
N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium p-toluenesulfonate,
N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium methosulfate,
3-methyl-1-vinylimidazolium methosulfate,
N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium acetate,
N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium bromide,
N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium chloride,
N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium fluoride,
N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium nitrate, N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium phosphate, 1,3-bis (dimethylamino) isopropyl methacrylate,
4- (N, N, -diethylamino) -1-methylbutyl acrylate,
2- (N, N-diethylamino) ethyl acrylate,
2- (N, N-diethylamino) ethyl methacrylate,
3- (N, N-diethylamino) propyl acrylate,
N- (1,1-dimethyl-3-dimethylaminopropyl) acrylamide,
3,6-dimethyl-3,6-diazaheptylacrylate,
2- (N, N-dimethylamino) ethyl acrylate,
2- (N, N-dimethylamino) ethyl methacrylate,
N- (2-dimethylaminoethyl) acrylamide,
N- (2-dimethylaminoethyl) methacrylamide,
3- (N, N-dimethylamino) propylacrylamide,
2- (5-ethyl-2-pyridyl) ethyl acrylate,
2-phenyl-1-vinylimidazole,
2-methyl-1-vinylimidazole,
1-vinylimidazole,
2-methyl-5-vinylpyridine,
2-vinyl pyridine,
4-vinyl pyridine.

Suitable anionic comonomers are
Aconitic acid,
2-acrylamido-2-methylpropanesulfonic acid,
3-acrylamidopropane-1-sulfonic acid,
Acrylic acid,

Methacrylic acid,
4-acryloyloxybutane-1-sulfonic acid,
3-acryloyloxypropionic acid,
3-acryloyloxybutane-1-sulfonic acid,
3-acryloyloxypropane-1-sulfonic acid,
4-t-butyl-9-methyl-8-oxo-7-oxa-4-aza-9-docensulfonic acid,
α-chloroacrylic acid,
Maleic acid,
Chloromaleic acid,
2-methacryloyloxyethyl-1-sulfonic acid,
Citric acid,
Crotonic acid,
Fumaric acid,
Mesaconic acid,
α-methylene glutaric acid,
Monoethyl fumarate,
Monomethyl-α-methylene glutarate,
Monomethyl fumarate,
Vinyl sulfonic acid,
p-styrene sulfonic acid,
4-vinylbenzylsulfonic acid,
Acryloyloxymethylsulfonic acid,
4-methacryloyloxybutane-1-sulfonic acid,
2-methacryloyloxyethane-1-sulfonic acid,
3-methacryloyloxypropane-1-sulfonic acid,
2-acrylamidopropane-1-sulfonic acid,
2-methacrylamido-2-methylpropane-1-sulfonic acid,
3-acrylamido-3-methylbutane-1-sulfonic acid.

Preferred cationic or anionic comonomers are N-vinylbenzyl-N, N, N-trimethylammonium chloride, N- (3-acrylamido-3,3-dimethylpropyl) -N, N, N-trimethylammonium metho sulfate, N-2- (methacryloyloxyethyl) -N, N, N-trimethylammonium methosulfate, N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium chloride, 2- (N, N-dimethylamino) ethyl acrylate, N- (2-dimethylaminoethyl) acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, 3-acrylamidopropane-1-sulfonic acid, acrylic acid and methacrylic acid.

The remaining monomer components can be (meth) acrylic acid esters, (meth) acrylonitrile, styrene or vinyl esters of acetic or propionic acid.

Polyacrylamide, polyacrylic acid and copolymers of acrylamide with the preferred anionic or cationic monomers in any composition are preferred.

Suitable photographic processing chemicals are black and white developers, color developers, bleaching agents, fixing agents and bleach-fixing agents.

In addition to the additive according to the invention, these photographic processing chemicals contain the usual active ingredients and auxiliaries. Details can be found in the exemplary embodiments.

The process for producing the granules according to the invention is characterized in that active ingredients and auxiliaries of a photographic processing bath are ground together to a particle size <2 mm, preferably 0.5 to 1 mm, then with the addition of a granulating liquid, which contains the copolymer defined above, undergoes powder agglomeration, dries in vacuo and is packaged in a water-vapor-tight manner.

The granules produced in this way are mechanically stable, of uniform grain size, show a high dissolution rate and unlimited durability, are dust-free and free-flowing.

The solid constituents are usually comminuted to particle sizes of <10 μm by jet milling. The powder agglomeration is preferably carried out in a fluidized bed, the granulation liquid, for example 200 ml of water per kg of powder, being added to the particles to be agglomerated.

If not all components of a photographic processing bath can be granulated together, e.g. Antioxidant and alkali dispenser from a color photographic developer, these developer components can be individually granulated, but packed together.

In the case of components which are particularly sensitive to oxygen, it is preferable to carry out the grinding, granulating, drying, mixing and packaging under a protective gas, for example nitrogen.

In addition to the developer substance, color photographic developer granules contain antioxidants and alkali donors as essential granule components. These three components are preferably granulated separately. The other additives such as anti-limescale, heavy metal complexing agents, sodium sulfite and alkali halide can be granulated together with one or more of the essential components.

All developer compounds which have the ability to react in the form of their oxidation product with color couplers to form azomethine or indophenol dyes can be used as the color developer compound. Suitable color developer compounds are aromatic compounds of the p-phenylenediamine type containing at least one primary amino group, for example N, N-dialkyl-p-phenylenediamines such as N, N-diethyl-p-phenylenediamine, 1- (N-ethyl-N-methanesulfonamidoethyl) -3 -methyl-p-phenylenediamine, 1- (N-ethyl-N-hydroxyethyl) -3-methyl-p-phenylenediamine and 1- (N-ethyl-N-methoxyethyl) -3-methyl-p-phenylenediamine. Other useful color developers are, for example, in. Amer. Chem. Soc. 73 , 3106 (1951) and G. Haist, Modern Photographic Processing, 1979, John Wiley and Sons, New York, page 545 ff.

Bleaching agents contain an iron (III) complex or an iron (III) complex salt and a rehalogenating agent.

Furthermore, the bleach granules can contain corrosion inhibitors, for example ammonium nitrate, complexing agents, for example ethylenediaminetetraacetic acid (EDTA), propylenediaminetetraacetic acid (PDTA), diethylenetriaminepentaacetic acid (DTPA) and nitrilotriacetic acid (NTA), and agents for setting the desired pH, for example ammonium carbonate.

The Fe (III) complexes or complex salts are the Fe (III) complexes or (NH₄) Fe (III) complex salts of EDTA, PDTA, DTPA and NTA. Suitable rehalogenating agents are alkali and ammonium halides, e.g. NaBr, KBr, NH₄Br and NaCl.

The iron (III) complex or the iron (III) complex salt preferably makes up 20 to 50% by weight of the finished granules; the rehabilitation agent preferably makes up 40 to 70% by weight of the finished granulate.

Fixatives usually contain a thiosulfate, e.g. Ammonium or sodium thiosulfate. Complexing agents such as ethylenediaminetetraacetic acid and agents for adjusting the desired pH such as sodium carbonate can be considered as further constituents of the fixing agents.

In the case of bleach-fixing agents, the bleaching agent and fixing agent are granulated together. In this case, the addition of a rehalogen is not necessary.

example 1 Granulation of the alkali part of a developer for processing color negative films

The following chemicals are mixed to granulate the alkali part for 10 l ready-to-use developer regenerator solution:

The mixture is comminuted in an Alexander mill to about 0.5-0.6 mm grain size and granulated in an air stream on a commercially available fluidized bed granulator (Strea 1 laboratory device from Aeromatic, Bubendorf / Switzerland).

For this, 80 ml of water are sprayed on as granulating liquid in 3 - 4 min.

After granulation, drying is carried out in the same device by heating the fluidizing air to 60 ° C. for 4-5 minutes.

Characteristics:

The granulate is free-flowing, but very dusty. If you screen off the dust content, new dust particles quickly form again, caused by strong abrasion.

If the granulating liquid water is replaced by a 0.05% strength by weight aqueous solution of polyacrylamide A, then a dust-free granulate characterized by extremely low abrasion is obtained. Polyacrylamide A is a polyacrylamide with an average molecular weight of 7 · 10⁶ ·

Example 2 Production of a granulate for 10 l ready-to-use solution of the stabilizing bath regenerator for processing color negative paper

The following chemicals are mixed and crushed on the Alexander Mill to about 0.5 - 0.6 mm grain size:

When trying to produce granules with water as a spray, no grain build-up can be obtained. Arise only a few agglomerates that disintegrate very easily (eg by shaking).

However, if a 0.05% by weight aqueous solution of acrylamide A is used (120 ml / kg premix), granules which flow well, are quickly soluble and have a low dust content are formed.

Example 3 Two-stage production of a bleach-fix bath granulate

A bleach-fix bath granulate is produced by mixing two individual granules A and B. The following quantities of chemicals are used for 10 l ready-to-use regenerator:

Production of the granulate A:

The chemicals listed under A are ground in an Alexander mill to about 1 mm grain size and then ground in an air jet mill to a particle size of 5 microns. The ground material is then granulated in about 500 g portions on the fluidized bed granulator mentioned in Example 1. For this purpose, 50 ml of water as granulating liquid are sprayed into the fluidized bed within about 2 minutes. The mixture is then dried by heating the fluidizing air to 70 ° C. for about 6 minutes. The gut grain is separated from about 5% undersize (<0.2 mm) by sieving. It is then dried in vacuo at room temperature.

Production of granulate B:

After mixing in the same granulator, the chemicals listed under B are granulated in about 7 minutes by spraying on 50% by weight ammonium iron EDTA solution which contains excess ammonia. 200 ml of this solution are sprayed onto 600 g of mixture B at room temperature. The mixture is then dried by heating the fluidizing air to 70 ° C. for 10 minutes. After the oversize has been sieved, it is dried for 3 to 4 hours in vacuo at room temperature.

Granules A and B are mixed to produce the ready-to-use mixed granulate.

911 g of granules A and 578 g of granules B provide the required amount of mixed granules for 10 l of bleach-fixer regenerator.

Example 4 One-step production of the bleach-fix bath granulate

The following chemicals are mixed and crushed on an Alexander mill to about 0.5 to 0.6 mm grain size. (For 10 l ready-to-use regenerator.)

This ground material is then granulated in 500 g portions on the commercially available Strea-1 fluidized bed granulator. 60 ml of the 0.05% strength by weight aqueous solution of a 1: 1 copolymer of acrylamide and acrylic acid with an average molecular weight of 11.10masse are sprayed on as the granulating liquid in about 5 minutes. Thereafter, as usual, drying is carried out by heating the fluidizing air to 70 ° C. for 6 minutes. The granules obtained are then dried in vacuo at room temperature for 3 hours after sieving about 1% by weight oversize.

The result is a dust-free, free-flowing and quickly soluble granulate. Compared to Example 3, the one-step process of Example 4 is much simpler.

If granulation is used instead of the copolymer solution using 60 ml of water or 60 ml of 50% by weight iron ammonium EDTA solution, the granulation process with water causes the individual chemicals to separate (no homogeneous granules). Large product clumps form when using NH₄FeEDTA solution. In addition, there is strong dust formation in both cases.

Example 5 Production of a fixing bath granulate

The following chemicals are mixed in the specified ratio to produce a granulate for 10 l of ready-to-use regenerator solution:

After comminution on the Alexander mill, the mixture is ground in an air jet mill to an average particle size of about 5 μm.

About 700 g of this mixture are per batch in the granulator used in Example 1 by spraying 110 ml of water granulated within 5 min. The spraying is interrupted several times in order to achieve an even grain size distribution. The granules obtained are then dried by heating the fluidizing air to 55 ° C. for 10 minutes. Any oversize or undersize is screened off. This is followed by drying in vacuo at room temperature for 2 hours.

The granules are slightly dusty and tend to stick together.

The same chemical mixture as stated above is ground on the Alexander Mill to a particle size of 0.5 to 0.6 mm.

About 700 g of this mixture per batch in the granulator described above by spraying 70 ml of a 0.05 wt .-% aqueous solution of a copolymer with the average molecular weight of 12 · 10⁶ from 40 wt .-% acrylamide and 60 wt. - Granulated% N-vinylbenzyl-N, N, N-trimethylammonium chloride in 3 min. The mixture is then dried for 5 minutes by heating the fluidizing air to 55 ° C. Any upper or lower grain that has formed is sieved off and the good grain is dried at room temperature in a vacuum for 1.5 hours.

A dust-free, free-flowing granulate is obtained which does not tend to cake.

Claims (2)

Photographic processing chemicals in the form of granules with an average particle diameter of 150 to 3000 µm containing the necessary active ingredients and auxiliary substances, characterized in that the granules additionally contain a polymer with a molecular weight of 500,000 to 14,000,000 in an amount of 1 to 1000 mg / kg of granules containing at least 80 mol% of acrylamide, acrylic acid, cationic monomer, or mixtures of acrylamide and cationic or anionic monomer. Photographic processing chemicals according to claim 1, characterized in that the polymer is polyacrylamide, polyacrylic acid or a copolymer of acrylamide and N-vinylvenzyl-N, N, N-trimethylammonium chloride, N- (3-acrylamido-3,3-dimethylpropyl) -N, N , N-trimethylammonium methosulfate, N-2- (methacryloyloxyethyl) -N, N, N-trimethylammonium methosulfate, N- (2-methacryloyloxyethyl) -N, N, N-trimethylammonium chloride, 2- (N, N-dimethylamino) ethyl acrylate, 2 - (N, N-Dimethylamino) ethyl methacrylate, N- (2-dimethylaminoethyl) acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, 3-acrylamidopropane-1-sulfonic acid, acrylic acid or methacrylic acid.