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
  • G03C1/04—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with macromolecular additives; with layer-forming substances
  • G03C1/047—Proteins, e.g. gelatine derivatives; Hydrolysis or extraction products of proteins
• • 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
  • G03C1/015—Apparatus or processes for the preparation of emulsions
• • 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
  • G03C1/04—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with macromolecular additives; with layer-forming substances
  • G03C1/053—Polymers obtained by reactions involving only carbon-to-carbon unsaturated bonds, e.g. vinyl polymers

Definitions

• This invention relates to the preparation of photographic emulsions having silver halide as the sensitive material in which the silver halide is prepared in dispersed form in a graft polymer of the. type which will be described herein.
• the polymer-silver halide dispersion is readily coagulated by adjustment of the pH.
• This invention also includes the products obtained thereby and the emulsions obtained by redispersing the coagulated silver halide grains in .a suitable vehicle.
• the monomer is a hydrophilic monomer it can amount to 595% of the weight of the mixture or if a hydrophobic monomer is employed it may amount to 15-40% of the weight of the mixture or both a hydrophilic and a hydrophobic monomer may be employed, the total of the monomers constituting at least 5% of the solid material which goes into the polymerization reaction.
• the polymerization is desirably effected in aqueous medium and the products thus obtained are compatible with photographic gelatins and degraded gelatin and thus are useful in the preparation of gelatin photographic emulsions.
• the polymers which are prepared in our invention are actual chemical combinations of a protein component and one or more polymerizable monomers and appear to be formed by a type of graft polymerization between the growing polymer chain and the protein molecule.
• These polymers consist of at least 60% by weight of combined hydrophilic material which can be saturated protein material alone or saturated protein and a hydrophilic monomer.
• hydrophilic monomers which are useful in this connection are acrylic acid, methacrylic acid, acrylamides, vinyl pyridine hydrochloride and the like.
• the saturated protein component which is employed in preparing the polymeric materials can be an unsubstituted protein such as gelatin, hydrolyzed gelatin, glue or casein or soybean protein or the like or it can be an acylated protein such as succinyl, phthalyl or acetyl prepared by reacting upon a protein such as .glue, gelatin or casein with an organic acid anhydride or chloride.
• Types of proteins which may be employed are those resulting fuom oxidation with hydrogen peroxide as described in Lowe and Gates Patent No. 2,691,582.
• One advantage of our invention resides in the fact that the protein employed to peptize the peptizing agent need not be in a highly purified state or of a high degree of polymerization. Thus low grades of gelatin, glue or casein or the like can be employed in preparing peptizing agents in accordance with our invention.
• Silver halide dispersions with our invention by forming an aqueous solution of the polymer and under agitated conditions either incorporating silver nitrate or alkali metal halide into that solution and running in a solution of the other or by .running solutions of both of these salts into the polymer solution.
• the solution may be in the pH range of 1.5 to 3.0 or it may be at a pH of 6 or more, such as may be obtained by the presence of ammonium hydroxide therein.
• the soluble salts resulting from the reaction are removed by coagulating the dispersion such as by adjusting the pH to a range of 4-5 whereupon silver halide grains coagulate therefrom.
• the solid material may be washed with cold distilled water.
• the silver halide may be prepared by using a peptizer such as gelatin and subsequently adding the polymer thereto so as to incorporate at least 2 parts thereof per part of solid material present with the pH outside of the coagulating range.
• the acid subsequently employed by reducing the pH to the coagulation point may be any acid which will give the desired pH with any adverse effect on the photographic material. Dilute aqueous sulfuric acid, acetic acid or phosphoric acid are useful for this purpose.
• Example 1 750 ml. of distilled water were heated to 40 C. and there was dissolved therein 12 grams of a graft polymer as prepared by example 12 of Dann, Illingsworth and Gates application Ser. No. 426,552. 70 grams of potassium bromide and 0.7 gram of potassium iodide. The pH of the solution was adjusted to 6.0 and the temperature was elevated to 60 C. A solution of 85 grams of silver nitrate in 850 ml. of distilled water at 62 C. was introduced therein with mechanical agitation over a period of 20 minutes and the pH was adjusted to 4.0 by carefully adding 2.5 normal sulfuric acid. A coagulum immediately formed.
• Example 2 The preceding example was repeated except that the polymer prepared in accordance with Example 7 of U. S. application Serial No. 426,551 of Illingsworth, Dann and Gates was employed as the peptizing material. A product having goodphotographic properties was obtained.
• Example 3 An experiment was carried out in the same manner as described in example 1 except that the polymer employed was that prepared in accordance with Example 15 of Ser. No. 426,552. A photographic film of good properties was found to have resulted,
• Example 4 A silver halide dispersion was prepared by mixing silver nitrate and potassium bromide in an aqueous solution of gelatin and after the formation of the silver halide, 24 parts of graft polymer as used in Example 1 was employed. The silver halide material thus obtained to which the polymer had been added was coagulated by adjusting the pH to 6.0 whereupon coagulation occurred and the emulsion was washed. Upon redissolving and incorporating in an emulsion a product having good photographic properties resulted.
• a method of preparing a washed silver halide dispersion which comprises precipitating silver halide in an aqueous solution of a gelatin-acrylic acid graft polymer, adjusting the pH of the mass to 4-5 whereby coagulation occurs, separating the coagulum from the liquid and redispersing in an aqueous liquid whereby a suspension substantially free of salts is formed.
• a method of preparing a washed silver halide dispersion which comprises precipitating silver halide in an aqueous solution of a gelatin-acrylic acid-acrylamide graft polymer, adjusting the pH of the mass to 4-5 whereby coagulation occurs and redispersing the resulting coagulum in an aqueous liquid whereby a suspension substantially free of salt is formed.
• a method of preparing silver halide dispersions substantially free of salts which comprises preparing a composition of a peptized silver halide in an aqueous solution of a water-soluble graft polymer prepared by the emulsion copolymerization of 5-95% of a saturated protein material and 95-5% of a monomeric material, -100% of which is hydrophilic material selected from the group consisting of acrylic acid, methacrylic acid, acrylamides, vinyl pyridine and mixtures thereof and 40-0% of which is hydrophobic material, adjusting the pH of the mass to 4-5 whereby coagulation is caused, separating the liquid from the solid material formed and redispersing that solid material in an aqueous liquid.
• a method of preparing silver halide dispersions substantially free of salts which comprises preparing a composition of a peptized silver halide in an aqueous solution of a water-soluble graft polymer prepared by the emulsion copolymerization of 595% of a saturated selected from the group consisting of acrylic acid, methacrylic acid, acrylamides, vinyl pyridine and mixtures thereof, adjusting the pH of the mass to 4-5 whereby coagulation is caused, separating the liquid from the solid material formed and redispersing that solid material in an aqueous liquid.
• a method'of preparing silver halide dispersions substantially free of salts which comprises precipitating silver halide in an aqueous solution of gelatin, adding to the mass a water soluble graft polymer in the proportion of at least 2 parts of the polymer to 1 of solids in the mass, the graft polymer being that which results from the emulsion polymerization of a composition comprising 595% of a saturated protein material and 5% of a monomeric material, 60-100% of which is hydrophilic material selected from the group consisting References Cited in the file of this patent UNITED STATES PATENTS Damschroder et al Apr. 10, 1951 Yutzy et. all Oct. 21, 1952

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Graft Or Block Polymers (AREA)
• Colloid Chemistry (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (4)

Cited By (8)

Citations (2)

• 0
  • BE BE544350D patent/BE544350A/xx unknown
• 1955
  • 1955-01-17 US US482416A patent/US2787545A/en not_active Expired - Lifetime
• 1956
  • 1956-01-13 GB GB1179/56A patent/GB820322A/en not_active Expired
  • 1956-01-16 FR FR71208D patent/FR71208E/fr not_active Expired

Patent Citations (2)

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