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
  • G03C1/34—Fog-inhibitors; Stabilisers; Agents inhibiting latent image regression
• • 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

• the present invention relates to a process for the production of photographic gelatino silver halide emulsions. More particularly, the invention relates to a process for the production of photographic gelatino silver halide emulsions by removing salts and water from the emulsions using as a flocculating agent, a copolymer made by copolymerizing p-vinylbenzene sulfonate with another vinyl compound.
• a photographic gelatino silver halide emulsion is usually prepared by (1) forming and growing the fine crystals of silver halide by the double decomposition of silver salts and halides in the presence of gelatin, (2) removing excess halide and soluble salt formed by the double decomposition to adjust the silver ion concentration and hydrogen ion concentration of the system, and (3) ripening the emulsion by adding, if necessary, suitable sensi tizers.
• the removal of the salts in the above step (2) has been conducted by gelling the emulsion by cooling after the formation of the fine crystals of a silver halide, cutting the thus formed gel into fine pieces, and then washing them with Water.
• a large amount of water and a long period of time are necessary for this process.
• the concentrations of the silver salts and the halide solutions are restricted to a high level, especially in the case of an emulsion -with a low ratio of gellatin to silver halide, since the concentration of gelatin must be maintained above a definite level in order to carry out the gelatin successfully.
• the restriction in the concentrations of the solutions causes considerable difliculty in the preparation of photographic emulsions of good quality.
• An object of the present invention is to provide an improved process for preparing a photographic gelatin silver halide emulsion having excellent photographic characteristics in which the flocculation can be effected by the addition of a small quantity of the specific flocculating agent, the re-dis-persion of the fiocculate can be easily conducted, and the viscosity increase of the emulsion obtained by the flocculation method is relatively small.
• the above object of this invention can be attained by flocculating gelatin together with the fine crystals of silver halides by using as the flocculating agent for photographic gelatino silver halide emulsions a copolymer made by copolymerization of a sodium, potassium or ammonium salt of p-vinylbenzene sulfonic acid with the vinyl compound represented by the following general formula:
• the suitable content of the vinylbenzene sulfonate in the copolymer used in this invention is between 30 and 95%, preferably between 60 and in molecular ratio of monomers contained in the copolymer. It is preferable that the intrinsic viscosity of the copolymer measured in a 1 N aqueous sodium nitrate solution at 30 C. is between 0.2 and 3.0.
• the sodium salt, the potassium salt and the ammonium salt of the copolymer all give similar results.
• the copolymerization of the p-vinylbenzene sulfonate and the above-mentioned hydrophilic vinyl monomer is preferably carried out in an aqueous solution.
• the copolymerization may be conducted with a high polymerization yield by a thermal polymerization using a peroxide, such as potassium persulfate and hydrogen peroxide, as an initiator, or an oxidation-reduction polymerization using a potassium peroxide-sodium bisulfite system and the like as the initiating system.
• a peroxide such as potassium persulfate and hydrogen peroxide
• Isopropanol or an alkyl mercaptan may be added in order to control the degree of polymerization.
• the yield for the copolymer is 70 g. (70% and the nitrogen analysis value is 1.62%, from which the content of potassium p-vinyl-benzene sulfonate in the copolymer is calculated to be 76.5 mol percent.
• the intrinsic viscosity of the copolymer when measured is a l N aqueous sodium nitrate solution at 30 C. is 1.02.
• the copolymer may be added to the emulsion or gelatin in any step before conducting the flocculation, but it is most preferable to add the copolymer of this invention after forming and growing the fine crystals of a silver halide in a gelatin solution.
• an acid In order to conduct the precipitation effectively, it is preferable to reduce the pH value of the system by the addition of an acid.
• An organic acid such as acetic acid, citric acid, salicylic acid and the like, and an inorganic acid, such as hydrochloric acid, sulfuric acid and the like can be used for this purpose.
• the pH for conducting the precipitation is preferably below 6, particularly below 5.
• the addition of a divalent salt, such as, a cadmium or zinc, is particularly eifective in the case of con ducting the precipitation at a comparatively high pH.
• the copolymer of this invention may be added to emulsion as a solid, followed by dissolving, but is suitably added as about a aqueous solution.
• the suitable amount of the copolymer to be added to the emulsion is about to /2 (by weight), preferably from about to A by weight of the gelatin contained in the emulsion at the time of flocculation.
• the concentration of the gelatin before flocculation is suitably about 0.5 to 10% by weight, preferably below 2% by weight.
• the process of the present invention may be applied to any silver halide emulsions, such as, a silver chloride emulsion, silver bromide emulsion, silver bromochloride emulsion, silver bromoiodide emulsion and silver bromo-iodochloride emulsion.
• the emulsion to which the process of this application can be applied may be chemically sensitized in accordance with a known method, such as, by compounds containing unstable sulfur, e.g., ammonium thiosulfate or allyl thiourea (cf., for example, P. Glafkides; Chimie Photographique; 2eme Edition Photocinema, Paul Montel, Paris, pp. 297-299 (1957)) or by gold compounds, e.g., a complex salt of mono-valent gold and thiocyanic acid, or by the combination thereof.
• a known method such as, by compounds containing unstable sulfur, e.g., ammonium thiosulfate or allyl thiourea (cf., for example, P. Glafkides; Chimie Photographique; 2eme Edition Photocinema, Paul Montel, Paris, pp. 297-299 (1957)
• gold compounds e.g., a complex salt of mono-valent gold and thi
• the emulsion may be also optically sensitized by the addition of cyanine dyes, merocyanine dyes, and the like (cf., Shinichi Kikuchi; Kagaku Shashin Binran (Scientific Photography Handbook); published by Maruzen K. K., Tokyo; pp. -24 (1959)).
• cyanine dyes having an acid group in the molecule of, US. Patent 2,503,776
• the similar merocyanine dyes of, US. Patent 2,493,758
• the emulsion may be stabilized by a stabilizer well known in the art, for example, by a heterocyclic compound, such as, benzotriazol, l-phenyl-S-mercaptotetrazol, 4 hydroxy-6-methyl-1,l,3,3a,7-tetrazaindene, or
• a 6-thioctic acid by a mercury compound such as mercumallylic acid (cf. Japanese patent publication No. 22,063/ 64), or by benzene sulfinic acid.
• a hardening agent such as, formaldehyde, mucochrolic acid, chrome alum, or a triazine derivative (cf., Belgian Patent 641,044) or such a hardening agent with a hardening aid, such as, resorcinol, and resorcyl aldehyde.
• a surface active agent such as saponin, sodium alkyl benzene sulfonate or an addition polymer of an alkyl phenol and sultone for improving the coating facility
• a surface active agent such as saponin, sodium alkyl benzene sulfonate or an addition polymer of an alkyl phenol and sultone
• the emulsion in this invention may be also sensitized by using a polyalkylene oxide derivative such as a condensation product of an alkyl phenol and polyethylene oxide.
• the photographic emulsion prepared by the process of this invention may be used for the production of color photographic films or color photographic printing papers by adding color couplers to it.
• the use of the copolymer in the process of this invention has such advantages that the amount of this polymer necessary for the flocculation may be less than that of the polymer consisting of only the p-vinylbenzene sulfonate, and the re-dispersion of the i iocculate obtained by the use of the copolymer of this invention can be carried out easily and the agglomeration of redispersed silver halide particles is reduced as compared with the case of using the known polymer of only p-vmylbenzene sulfonate. Moreover, the viscosity increase of the emulsion obtained by the process of this invention using the copolymer is less than in the case of using the polymer of only the p-vinylbenzene sulfonate.
• the preferable content of styrene groups is described as being between 97 and and particularly between 97 and while in the present invention the effective content of the styrene sulfonic acid is between and 30% particularly between 60 and 85%.
• the copolymer in this invention is a diiferent compound from the polymer in the Belgian patent and has different characteristics from those of the polymer in the Belgian patent.
• a photographic silver bronio-iodide emulsion was prepared as follows by using as the flocculating agent the copolymer (I) of acrylamide and potassium p-vinylbenzene sulfonate of which the intrinsic viscosity measured in a 1 N aqueous sodium nitrate solution at 30 C. was 0.870 and the molecular ratio of the p-vinylbenzene sulfonate was 66%.
• Silver nitrate g 100 Water to make 1200 ml.
• a photographic silver bromo-chloride emulsion was prepared as follows using as the flucculating agent for the emulsion a copolymer (II) of acryloyl morpholine and potassium p-vinylbenzene sulfonate of which the intrinsic viscosity measured in a 1 N aquecous solution of sodium nitrate at 30 C. was 0.740 and the molecular ratio of the p-vinylbenzene sulfonate was 64%.
• a copolymer (II) of acryloyl morpholine and potassium p-vinylbenzene sulfonate of which the intrinsic viscosity measured in a 1 N aquecous solution of sodium nitrate at 30 C. was 0.740 and the molecular ratio of the p-vinylbenzene sulfonate was 64%.
• Silver nitrate g 100 Water to make, 1300 ml.
• Solution 2 was added into solution 1 in 1 minute and the mixture was ripened for 5 minutes at that temperature. Thereafter, the temperature of the thus obtained emulsion was reduced to 50 C. in 15 minutes and after adding a 5% aqueous solution of compound II, followed by stirring thoroughly, 7.5 ml. of a 10% aqueous citric acid solution was added to adjust the pH to 4.0. When the agitation was stopped, flocculation occurred immediately and the emulsion was precipitated completely in 10 minutes. By decantation, 2600 ml. of the supernatant liquid was removed and then 2400 ml. of cold Water containing 3.7 ml. of 10 citric acid was added followed by stirring for 3 minutes.
• the emulsions prepared by using copolymers III and XIV had almost the same photographic characteristics as those of the photographic emulsion prepared in Example 1.
• the added amount of the copolymer may be comparatively small in the case where the molecular ratio of potassium p-vinylbenzene sulfonate is from 60 to The less the amount of the added copolymer, the easier is the redispersion of the flocculate and the lower is the increase in the viscosity of the emulsion obtained.
• EXAMPLE 4 After finishing the formation by precipitation of an ammonia-process high-sensitivity silver bromo-iodide emulsion (Ag 11.5 mol percent) containing gelatin 40 g. to 0.6 mol of the silver halide, 40 ml. of a 10% aqueous solution of the copolymer (the intrinsic viscosity in 1 N aqueous sodium nitrate solution at 30 C. was 1.38) of 77 mol percent of potassium p-vinylbenzene sulfonate and 23 mol percent of acryloyl morpholine was added with stirring.
• the system was diluted with cold water to 1.5 liters to reduce the concentration of gelatin to 2.7% and at the same time to reduce the temperature of the system to 23 C. Thereafter, 210 ml. of 10% sulfuric acid was added to the system while stirring during about 10 minutes to adjust the pH to 5.0. By stopping stirring, the emulsion was flocculated in the form of a fine precipitation flocculate. 1.3 liters of the supernatant liquid was removed. The flocculate was mixed with 2 liters of ol water containing 0.3 g. of salicylic acid followed by stirring to rinse the flocculate. Then, after allowing the system to stand, about 2 liters of the supernatant liquid was removed by decantation. This process was repeated three times.
• Example 2 The procedure of Example 1 was repeated using the copolymer (the intrinsic viscosity in 1 N NaNO solution at 30 C. was 0.87) of 66 mole percent of potassium p-vinylbenzene sulfonate and 34 mol percent of acrylamide instead of the copolymer in Example 4.
• a process for the production of a photographic silver halide emulsion by flocculating gelatin together with silver halide which comprises using as the flocculating agent a copolymer made by copolymerizing (1) a compound selected from the group consisting of sod1um p-vinylbenzene sulfonate, potassium p-vinylbenzene sulfonate and ammonium p-vinylbenzene sulionate with (2) a compound selected from the group consisting of l-vinyl- Z-methyl imidazole, acryloyl morpholine, ethoxymethyl acrylamide, and morpholino-methyl acrylamide.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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Cited By (7)

Citations (6)

• 1965
  • 1965-01-12 JP JP40001239A patent/JPS4924283B1/ja active Pending
• 1966
  • 1966-01-07 GB GB920/66A patent/GB1135622A/en not_active Expired
  • 1966-01-11 BE BE674943D patent/BE674943A/xx unknown
  • 1966-01-12 US US520064A patent/US3482980A/en not_active Expired - Lifetime
  • 1966-01-12 DE DE19661547829 patent/DE1547829A1/de active Pending

Patent Citations (6)

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