Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
  • G03C1/37—Antiseptic agents

Definitions

• Photographic silver halide material usually contains a support and applied thereon at least one light-sensitive silver halide emulsion layer and optionally further non-light-sensitive layers such as substrate layers, intermediate layers and protective layers.
• Gelatin is used exclusively or predominantly as a binder for these layers, which as a natural product is very strongly exposed to the attack by microorganisms. This leads to undesirable phenomena such as mold, odor, photographic defects and gelatin degradation, the latter recognizable by a lowering of the viscosity of the aqueous gelatin solution.
• other organic components of the photographic material are also subject to microorganism attack, for example polymers which are used in the materials (FL Stickley, J. Photo Sci. 34 , 111-112 (1986)).
• the finished additives are stored in aqueous solutions or dispersions 1 to 6 months before use.
• the solutions and dispersions must not contain low-boiling solvents such as ethanol, methanol or ethyl acetate. So far, these additives have ensured that the stored solutions are sterile.
• biocides must be added to the photographic material or the aqueous solutions of photographic additives used in its production, in particular the gelatin or the gelatin solutions, which remain largely in the material even after processing or in the case of Processing are washed out and contaminate the waste water.
• biocides are only effective from certain amounts. These amounts always refer to the total volume of the aqueous solutions. The less concentrated the solutions are in relation to the active ingredient, for example thickeners, the greater the amounts of biocide that are present in the photographic material when the solution is poured on.
• a thickener solution is 0.3% due to the high viscosity. If phenol is used as a biocide, 2 - 2.5 g / l (lower effectiveness limit) must be added. There are then 2 - 2.5 g phenol per 3 g thickener, which are introduced into the photographic material.
• the processed black and white materials contained metallic silver, that of his on the one hand has a certain bactericidal effect and therefore does not germinate as easily as the color films and supervisory materials, in which the silver is released during the processing process.
• the invention therefore relates to a photographic silver halide material with a support and at least one silver halide emulsion layer applied thereon, characterized in that the content of detectable biocides in the unprocessed material is less than 5 mg / m2, preferably less than 0.5 mg / m2.
• Such a material with sufficient durability arises, for example, when using a disinfection process with carbon dioxide or through disinfection of feed materials by a biocide, which decomposes quickly enough by itself.
• the material according to the invention can be produced, for example, by treating the raw materials at risk of attack with gaseous carbon dioxide under a pressure of at least 2 bar. There are no upper limits for the pressure, but for technical reasons it is advisable to limit the pressure treatment to 40 bar.
• the pressure treatment is therefore preferably carried out at a pressure of 4 to 40 bar.
• the pressure treatment happens in usual pressure chambers, which are initially charged with the solution or dispersion to be sterilized, for example an aqueous gelatin solution, and then with CO2 of the desired pressure. If necessary, the pressure chamber can be evacuated before loading with CO2 in order to largely remove the ambient air.
• the pressure treatment is carried out in particular at temperatures from 10 to 90 ° C, since damage to the product can occur at higher temperatures.
• the duration of the pressure treatment is not critical and can be within wide limits. In general, a treatment time of 5 minutes to 3 hours, preferably 5 minutes to 1 hour, will be sufficient.
• the substances at risk of attack can be subjected to the treatment in dry, as finely divided as possible, in moistened form, as an aqueous suspension, emulsion or solution.
• Gelatin in particular is to be subjected to CO2 treatment under pressure.
• the gelatin can be used in a dry or moist form (low in water form) or preferably in a form dissolved in water.
• All types of gelatin which are used for the production of a photographic silver halide material are preferably treated by the process according to the invention.
• the treatment can be at any time after the preparation of the gelatin and before the solution is poured. It is preferable to carry out the CO2 treatment as shortly as possible before using the gelatin in order to avoid possible contamination by microorganisms.
• aqueous suspensions, emulsions or solutions of photographic additives to so-called cold disinfection by treating them with compounds of the formula (I) (pyrocarbonate) RO - CO - O - CO - OR ′ (I) where R and R ′ are alkyl, aralkyl or aryl, preferably lower alkyl radicals, in particular ethyl and methyl, treated in an effective amount.
• the invention thus also relates to the use of pyrocarbonates of the formula (I), in particular the lower alkyl esters and preferably the methyl or ethyl esters, as disinfectants in the production of photographic materials.
• the aqueous non-gelatin-containing stock solutions are generally sterilized when pumping into larger storage containers by metering in the cold disinfectant using automatic metering systems in a continuous process.
• cold sterilizing agents can also be added and distributed by stirring briefly.
• the advantage of (I) is that it can be hydrolysed completely in a short time (a few minutes) by water present to photographically and ecologically harmless products (CO2 and lower alcohols). The products are no longer detectable in the solutions after 7 hours.
• a dosage of 4 - 100 ml / 100 l is used depending on the level of contamination by bacteria and the pH value. So the amount of the cold disinfectant can be reduced if the pH is low or the CO2 pressure is high (combined disinfection). Brief heating before the addition of the disinfectant can also be used.
• the treated solutions are germ-free and contain no germs after a standing time of several months.
• the solutions are made according to the conventional processes e.g. Germ count determination according to Koch, examined.
• the bacterial count is determined in the original solution and in the dilutions 10 ⁇ 2, 10 ⁇ 4 and 10 ⁇ 6, namely immediately after sampling and after 1, 2 and 6 months. At the same time it is examined for micro-fungi. A germ count of 100 germs / ccm must not be exceeded.
• Cold disinfection can be combined with various other ecologically sound methods: e.g. Short-term heating, UV radiation, CO3 treatment.
• Water itself which is on the one hand one of the most important feedstocks and on the other hand a cleaning and rinsing agent that is used in many ways in the manufacturing process, can also be sterilized by a compound according to the invention.
• a disinfection process known to the person skilled in the art, e.g. disinfection with ultra or microfiltration (see e.g. DE-OS 3 726 865), irradiation with ultraviolet light or ozonation as described by C. Nebel and W.W. Nezgod described in Solid State Technology (1984), October, pp. 185 to 193.
• the pyrocarbonic acid esters (cold sterilizing agents) used according to the invention can also be used by pouring a dilute aqueous or aqueous-alcoholic solution onto a photographic material which has already been prepared or by immersing it in such a solution.
• the gaseous use of pyrocarbonates is also possible.
• the photographic silver halide material can be a black and white material, for example a black and white film or black and white paper, an X-ray material, a color photographic material or any other photographic silver halide material, in particular a material for producing essentially silver-free photographic images ( Color images).
• color photographic materials are color negative films of high and highest sensitivity, e.g. > 20 DIN, color reversal films, color positive films, color photographic paper, color reversal photographic paper, color sensitive materials for the color diffusion transfer process or the silver color bleaching process.
• Suitable supports for the production of photographic materials are e.g. Films and foils of semi-synthetic and synthetic polymers such as cellulose nitrate, cellulose acetate, cellulose butyrate, polystyrene, polyvinyl chloride, polyethylene tetraphthalate and polycarbonate and paper laminated with a baryta layer or ⁇ -olefin polymer layer (e.g. polyethylene).
• These carriers can be colored with dyes and pigments, for example titanium dioloid. They can also be colored black for the purpose of shielding light.
• the surface of the support is generally subjected to a treatment in order to improve the adhesion of the photographic emulsion layer, for example a corona discharge with subsequent application of a substrate layer.
• the color photographic materials usually contain at least one red-sensitive, green-sensitive and blue-sensitive silver halide emulsion layer and, if appropriate, intermediate layers and protective layers.
• Gelatin in particular is used as a binder for these layers.
• gelatin of the different layers of the photographic silver halide material can be replaced in whole or in part by other synthetic, semisynthetic or naturally occurring polymers.
• Synthetic gelatin substitutes are, for example, polyvinyl alcohol, poly-N-vinylpyrrolidone, polyacrylamides, polyacrylic acid and their derivatives, in particular their copolymers.
• Naturally occurring gelatin substitutes are, for example, other proteins such as albumin or casein, cellulose, sugar, starch or alginates.
• Semi-synthetic gelatin substitutes are usually modified natural products.
• cellulose derivatives such as hydroxyalkyl cellulose, carboxymethyl cellulose and phthalyl cellulose and gelatin derivatives which have been obtained by reaction with alkylating or acylating agents or by grafting on polymerizable monomers.
• the gelatin can be obtained by acidic or alkaline digestion. Oxidized gelatin can also be used. The preparation of such gelatins is described, for example, in The Science and Technology of Gelatine, edited by AG Ward and A. Courts, Academic Press 1977, page 295 ff.
• the gelatin used in each case should contain the lowest possible level of photographically active impurities (inert gelatin). High viscosity, low swelling gelatins are particularly advantageous.
• the silver halide present as a light-sensitive component in the photographic material can contain chloride, bromide or iodide or mixtures thereof as the halide.
• the halide content of at least one layer can consist of 0 to 40 mol% of iodide, 0 to 100 mol% of chloride and 0 to 100 mol% of bromide. It can be predominantly compact crystals, e.g. are regular cubic or octahedral or can have transitional forms.
• platelet-shaped crystals can preferably also be present, the average ratio of diameter to thickness of which is preferably at least 5: 1, the diameter of a grain being defined as the diameter of a circle with a circle content corresponding to the projected area of the grain.
• the layers can also have tabular silver halide crystals in which the ratio of diameter to thickness is substantially greater than 5: 1, e.g. 12: 1 to 30: 1.
• the silver halide grains can also have a multi-layered grain structure, in the simplest case with an inner and an outer grain area (core / shell), the halide composition and / or other modifications, such as doping of the individual grain areas, being different.
• the average grain size of the emulsions is preferably between 0.2 ⁇ m and 2.0 ⁇ m, the grain size distribution can be both homo- and heterodisperse. Homodisperse grain size distribution means that 95% of the grains do not deviate from the mean grain size by more than ⁇ 30%.
• the emulsions can also contain organic silver salts, e.g. Silver benzotriazolate or silver behenate.
• Two or more kinds of silver halide emulsions, which are prepared separately, can be used as a mixture.
• Biocides in the sense of the invention are all compounds which kill bacteria, fungi, algae etc. and largely remain in the material. Depending on the effect, they are referred to as bactericides, fungicides, etc.
• Biocides are, for example, phenol, 2-propenylphenol, 2-isopropyl-5-methylphenol, 2-isopropyl-4-chloro-5-methylphenol, 3-methyl- 4-chlorophenol, 2,5-dimethyl-4-chlorophenol, 2-benzyl-4-chlorophenol, benzoic acid, 5-bromo-5-nitro-1,3-dioxane, 2-bromo-2-nitro-1,3- propylene glycol, benzisothiazolon-3, 5-chloro-2-methyl-4-isothiazolin-3-one.
• the photographic silver halide materials also contain the usual additives such as sensitizers, stabilizers, color couplers, UV absorbers, matting agents, hardening agents, correction dyes, etc.
• sample A spiked with 2 g phenol per kg solution is as stable as sample E and F spiked with little or no phenol, which were additionally sterilized by carbon dioxide pressure treatment.
• the material was cast on a paper pad and dried. Round specimens with a diameter of 30 mm were cut out of these and these were placed in petri dishes on sterile culture medium (malt extract agar Merck No. 5398) and incubated for 2 weeks at room temperature.
• sterile culture medium malt extract agar Merck No. 5398
• the emulsion layers G to M given below were prepared with the concentrations of phenol in the casting solutions given in the table.
• samples G to K were produced by known methods without special aseptic precautions, samples L and M were treated with carbon dioxide gas at 30 bar, 40 ° C., for 30 minutes before pouring and poured in a germ-free atmosphere.
• Table 3 sample Phenol content of the casting solution [%] Phenol content of the layer material [mg / m2] Condition after incubation G 2nd 800 (comparison) 3rd H .2 200 (comparison) 3rd I. .02 30 (comparison) 2nd K .002 3 (comparison) 1 L .002 3rd 3rd M 0 0 3rd Scheme for evaluation: "3": test specimen free of fungi "2”: DUT 30 to 50% overgrown with fungi "1”: DUT overgrown by more than 50% of fungi.
• Copolymers of acrylamide and acrylamidoisobutylene sulfonic acid (1: 4 quantities in g) as the sodium salt.
• the solution was made up with deionized factory water at 0.5%.
• Plasticizer dispersion Polyethyl acrylate latex 30% in water Particle size 100 nm
• Silver opacity enhancer Polydextran M 100,000 10% aqueous solution Table 4 Germ count after cooking storage solution Amount of disinfectant after 1 day after 1 month after 3 months original 10 ⁇ 2 10 ⁇ 4 10 ⁇ 6 original 10 ⁇ 1 10 ⁇ 4 10 ⁇ 6 original 10 ⁇ 2 10 ⁇ 4 10 ⁇ 6 Factory water - ⁇ ⁇ 10th 1 ⁇ ⁇ 5 0 ⁇ ⁇ 4th 1 2 g / l 0 0 0 0 0 0 0 0 0 0 0 Solution 1 - ⁇ ⁇ 37 2nd ⁇ ⁇ 100 2nd ⁇ ⁇ 10th 2nd 2 g / l 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Solution 2 - ⁇ ⁇ 100 20th ⁇ ⁇ 10th 3rd ⁇ ⁇ 40 5 2 g / l 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Solution 3 -
• the addition of the pyrocarbonate according to the invention provides protection against contamination of the aqueous additional solutions for up to 3 months or more.
• a red-sensitized silver halide emulsion consisting of the following components: 17.66 g gelatin 4.55 g cyan coupler C-1 4.55 g dibutyl phthalate Silver halide AgBr / I with 2 mol% iodide 20.4 g AgNO3 400 g water
• solutions 1, 3, 4 and 8 from Example 3 are added in each case in amounts such that 3 or 6 parts of active substance are used for 100 parts of gelatin.
• the sensitometric data are determined.
• the material is stored for 7 days at 60 ° C / 34% rel. Before processing. Humidity and 7 days at 35 ° C / 90% rel. Humidity. Table 5 Additive % Fresh sample 7 days 60 ° C / 34% rel. LF 7 days 35 ° C / 90% rel.
• a color photographic recording material which is suitable for a rapid processing process was produced by placing the following layers on a support on paper coated on both sides with polyethylene were applied in the order given.
• the quantities given relate to 1 m2.
• the corresponding amounts of AgNO3 are given.
• the layers are applied by means of a curtain caster according to DE-A-32 38 905, the casting solution for the 8th layer only meeting the layer package of the other casting solutions at the caster edge.
• the layered structures were exposed behind a gray wedge and subjected to a rapid processing process, the literature-known RA-4 process.

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• 1989
  • 1989-07-20 DE DE19893924110 patent/DE3924110A1/de not_active Withdrawn
• 1990
  • 1990-07-07 EP EP90112980A patent/EP0410184A1/fr not_active Withdrawn
  • 1990-07-16 JP JP18547490A patent/JPH0359552A/ja active Pending

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