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
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
  • G03C5/264—Supplying of photographic processing chemicals; Preparation or packaging thereof
  • G03C5/265—Supplying of photographic processing chemicals; Preparation or packaging thereof of powders, granulates, tablets
• • 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
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/30—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
  • G03C7/407—Development processes or agents therefor
  • G03C7/413—Developers

Definitions

• the present invention relates to a granular color photographic developer and a method for producing such a developer which can be quickly dissolved.
• Color photographic developers usually contain a number of solid components, for example the actual developer substance, antioxidants, complexing agents, sodium sulfite, alkali donors and alkali halides. Since these compounds can react chemically with one another, they are packaged separately and only mixed immediately before use. Suitable formulations are powders and liquid concentrates, the latter having become more and more established over the years, especially since some developers contain liquid constituents which, understandably, cannot be formulated in powder form, for example benzyl alcohol.
• the three or four concentrates are then mixed in certain mixing ratios and, if appropriate, with the addition of water with stirring.
• compositions can be produced which contain all the solid constituents of a color photographic developer by spraying the developer substance in dissolved form into a fluidized bed which separates the fine material components escaping from the fluidized bed with the exhaust gas and as nuclei for the formation of granules returns the fluidized bed, influences the granulation process in the fluidized bed by setting the classifying gas flow in such a way that a granulate of the size specified by the classifying gas flow is produced, removes the finished granulate via one or more counterflow gravity classifiers used in the inflow floor of the fluidized bed apparatus, dries in vacuo , mixed with the other components of the developer, granulated by any process, and packed in a water vapor-tight manner.
• the invention thus relates to a process for producing a granulated preparation of the solid constituents of a color photographic developer, characterized in that the developer substance of a color photographic developer is sprayed in dissolved form into a fluidized bed, which separates the fine material portions escaping from the fluidized bed with the exhaust gas and as germs leads back to the fluidized bed for the formation of granules, influences the granulation process in the fluidized bed by adjusting the classifying gas flow in such a way that a granulate in the range given by the classifying gas flow Size arises, the finished granules are removed via one or more countercurrent gravity classifiers used in the inflow base of the fluidized bed apparatus, dried in vacuo, mixed with the other components of the developer, granulated by any process, and packed in a water-vapor-tight manner.
• the granulate of the developer substance of a color photographic developer produced in this way is mechanically stable, of uniform grain size, shows a high dissolution speed and unlimited durability, is dust-free and free-flowing.
• the grains are particularly spherical.
• An aqueous solution of the developer substance is preferably used, the concentration of which is in particular 10 to 70% by weight.
• the average particle diameter of the developer substance granules should preferably be ⁇ 150 ⁇ m and is in particular 150 to 3,000 ⁇ m.
• the method according to the invention allows a very narrow particle diameter distribution.
• ⁇ 80% of the grains are within a range that does not deviate from the desired grain diameter by more than ⁇ 100 ⁇ m.
• a protective gas for example nitrogen.
• the other solid constituents of the developer such as antioxidants, alkali donors, limescale inhibitors, complexing agents for heavy metal ions, sodium sulfite and alkali halide can be granulated by any process.
• a suitable method is, for example, that the substance to be granulated is ground to a particle size of ⁇ 10 ⁇ m, then optionally subjected to powder agglomeration with the addition of a granulating liquid and a binder, and dried in vacuo.
• Antioxidants and alkali dispensers should preferably be granulated separately.
• the remaining constituents can also be granulated separately or partly with the antioxidant and partly with the alkali dispenser.
• the auxiliaries are granulated in particular to the same mean grain diameter as that of the developer substance; the deviation of the individual granules from the average grain diameter can be greater than with the developer substance.
• the granulate mixture produced in this way is mechanically stable, of uniform grain size, shows a high rate of dissolution and unlimited shelf life, is dust-free and free-flowing.
• 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.
• Another object of the invention is a granule mixture containing a granulated developer substance, a granulated antioxidant and a granulated alkali dispenser, characterized in that the granulated developer substance is spherical and has an average particle diameter ⁇ 150 microns, 80% of the grains being within a range that deviates from the desired grain diameter by no more than ⁇ 100 ⁇ m.
• the compound is used as a 50% by weight aqueous solution.
• the granulation takes place in a glass shot with a diameter of 225 mm by repeatedly spraying the aqueous solution onto solid germs located in the fluidized bed.
• a quantity of about 1 kg of solid CD 3 as starting granules is placed on the perforated bottom of a glass shot with a diameter of 225 mm according to DE-A-35 07 376, example 1, via a filling funnel. Then the fluidizing gas flow is switched on: flow cross-section 225 mm diameter, throughput 127 kg / h nitrogen at 100 ° C. Exhaust gas temperature 62 ° C.
• a 50% by weight aqueous CD 3 solution kept at room temperature is sprayed into the fluidized bed of inert gas via a two-component nozzle.
• the product is fed to the nozzle via a peristaltic pump.
• the solid nuclei (or the starting granulate) initially formed from the evaporating droplets in the fluidized bed grow onion-like to the desired size through repeated spraying.
• the diameter of the individual grains can be set within narrow limits via the speed of the classifying gas flow.
• An extended attachment with a diameter of around 500 mm above the glass shot serves as a pre-cutter for the medium grain and to solidify the spray droplets that have not hit the bed.
• the fine material to be separated from the exhaust gas flow is returned by a top filter.
• the filter is cleaned, the fine material falls back into the fluidized bed in an avalanche-like form so that the germs are again exposed to the spray jet.
• the finished granulate is discharged by the classifier after 20 minutes.
• the bed content remains at around 1 kg CD 3.
• the finished granulate is collected in a sealed bottle that is operated as a change template.
• the gas throughput through the classifier is 9.5 kg / h at 62 ° C.
• Granule color very light, almost colorless, no pink color cast.
• Granulate form beads Bulk density: 730 g / l; the product is free-flowing and dust-free
• the granules are 90 minutes. post-dried at 40 ° C in a vacuum.
• Mixture C Mix D a) Disodium salt of 1-hydroxyethane-1,1-diphosphonic acid 34 g --- b) sodium sulfite 39 g 39 g c) ethylenediaminetetraacetic acid --- 24 g d) potassium carbonate 336 g 336 g e) sodium hydrogen carbonate 15 g 15 g f) potassium bromide 15 g 15 g 439 g 429 g
• the individual granules A, B, C and D are mixed in the following weight ratio in a laboratory mixer, whereby work must be carried out with the exclusion of moisture: Granules A 4.52 g Granules B 2.4 g Granules C 21.95 g Granules D 21.45 g total weight 50.32 g
• the mixed granulate is packed in paper bags lined with plastic and aluminum foil, with the exclusion of moisture (conduction of very dry air), which are sealed immediately.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Glanulating (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Developing Agents For Electrophotography (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=6362255

Family Applications (1)

Country Status (3)

Cited By (8)

Families Citing this family (10)

Family Cites Families (3)

• 1988
  • 1988-09-03 DE DE19883830022 patent/DE3830022A1/de not_active Withdrawn
• 1989
  • 1989-08-22 EP EP19890115442 patent/EP0358035A3/fr not_active Withdrawn
  • 1989-09-02 JP JP22640189A patent/JPH02109043A/ja active Pending

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