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
  • G03C1/30—Hardeners
• • 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
  • G03C1/30—Hardeners
  • G03C1/307—Macromolecular substances

Definitions

• the invention relates to hardened photographic layers, which contain proteins, in particular gelatin as layer forming material, as well as to a process for producing said layers.
• Metal salts such as chromium, aluminum and zirconium salts; aldehydes and halogenous aldehyde compounds, such as formaldehyde, dialdehydes and mucochloric acid; 1,2- and 1,4-diketones, such as cyclohexane- 1,2-dione; quinones; chlorides of dibasic organic acids; dianhydrides of tetracarboxylic acids; compounds with several reactive vinyl groups, such as vinyl sulphones, acrylamides; compounds with at least 2 heterocyclic rings which can easily be split off, such as ethylene oxide and ethylene imine; polyfunctional methane-sulphonic acid esters.
• These hardening agents are compounds of low molecular weight.
• hardeners of low molecular weight As well as the hardeners of low molecular weight referred to above, others which are of high molecular weight are also known. Thus, polyaldehydes, such as the periodic acid oxidation products of starch, have been described as hardeners. However, they have the disadvantage of possessing only a low hardening equivalent, since even in the most favourable case only two aldehyde groups are present to each hexose unit.
• the maleic acid semiesters of alcohols of high molecular weight, such as polyvinyl alcohol have similar disadvantages.
• German patent specification 1,083,051 discloses a process for the production of compound polymers of polyacrolein, according to which macromolecular polymerisation products of acrolein are reacted with natural or synthetic polymers, which contain groups reactive with carbonyl groups.
• German patent specification 1,083,051 describes inter alia that the water solubility of gelatin layers can be superfically reduced by water-soluble bisulphite compounds of polyacrolein. The procedure adopted is to treat a gelatin layer, cast on to a glass plate, after drying, with an aqueous polyacrolein-sulphurous acid solution. Since the high polymer hardening agent cannot penetrate into the layer, the hardening of the gelatin only takes place on the surface of the layer.
• the hardener is used in relatively very high concentration.
• the hardening is not homogeneous. It is an object of the present invention to avoid the disadvantages described above.
• a further object is to provide a new method for hardening photographic layers which contain proteins as binding agents, thus providing photographic material having excellent physical and photographic properties.
• proteincontaining photographic layers preferably of gelatin
• the process utilises the surprisingly strong dependence on pH value of the speed of the cross-linking reaction.
• small quantities of hardener for example O.54%
• the effect is particularly apparent.
• Completely homogeneous, unhardened mixtures are obtained at pH values of 46 with gelatin.
• the cross-linking reaction proceeds fairly slowly in this pH range, so that there is practically none or only very little hardening. If the pH value is raised to above 7 immediately before casting the layer, then layers are obtained which reach their maximum degree of hardening just after drying. If the pH value is not raised before the casting a hardening action does not, for practical purposes, result even with relatively long storage. It is only by an alkali treatment of the layer that the layer melting point spontaneously rises and layers which are resistant to boiling and handling are obtained.
• the hardening of the layers can also be achieved by brief treatment of the layers with gaseous ammonia or amines. In each case, swelling and solubility of the layers are reduced to the desired degree and strongly hardened, non-brittle
• the new hardeners are incorporated into the layers before casting, advantageously as l-5% aqueous solutions.
• the viscosity of the casting solution does not rise in practice, even at pH 7.
• the quantities of substance necessary for the hardening are extremely small. 0.54% of the hardener, based on the gelatin dry weight, are sufficient. Layer melt-ing points higher than 100 C. are obtained even by adding 0.5% of hardener.
• the polyacrolein-sulphurous acid compounds are inactive photographically.
• the process according to the invention is particularly advantageous with highly sensitive gelatinsilver halide emulsions, the sensitivity of which is undesirably modified by changing the speed of diffusion of the developer.
• the use of high-polymer polyacrolein-bisulphite compounds with a molecular weight higher than 3000 also provides the advantage of resistance to diffusion.
• the sulphurous acid adducts of polyacrolein can be added to a gelatin solution which serves for the production of photographic auxiliary layers, such as intermediate, backing, filter or protective layers or even gelatin-silver halide emulsions which can contain the usual photographic additives and/or dyestuff components and/ or spectral sensitisers.
• the bisulphite compounds of polyacrolein produced with sulphurous acid are hydro oxysulphonic acids of high molecular weight and as such precipitate gelatin. Consequently, their solutions must be adjusted to pH values between approximately 4 and 5.5 before being added to the gelatin-silver halide emulsions. It is only in this way that completely homogeneou mixtures of gelatin and hardener are obtained.
• the precipitation of gelatin with the acid polyacrolein-bisulphite compound can be cancelled out by adding sodium bicarbonate solutions. The process is reversible as long as too highly alkaline pH values are not used.
• the melting point of the layer is raised by the processing in alkali baths.
• the photographic properties are not changed.
• pH value of the emulsion 5. 5 7 8. 5
• Copolymers of acrolein which can be used as harden ing agents according to the invention in the form of the bisulfite addition compounds are described, for example, in Houben-Weyl, Methoden der organischen Chemie, volume XIV/ 1, page 1086. Suitable components for acrolein are amongst others acrylonitrile, acrylic acid, acrylic acid esters, acrylamide, styrene, vinylacetate etc. The copolymers should contain at least 50 mol percent of acrolein.
• the bisulfite-addition compounds of the copolymers are prepared according to methods suitable for polyacrolein-bisulfite addition products.
• composition of the said baths are not critical, they only have to cause the adjustment of the pH-value in the protein layers to values of above 7.
• the kind of the alkaline agent of said treating bath is not especially critical and can be selected according to the requirements of the protein layer, which is to be hardened. Suitable are, for example, hydroxides, carbonates, phosphates or borates of alkali metals, such as sodium or potassium. Furthermore, hydroxides of earth alkali metals, such as calcium or barium hydroxides and ammoniac or organic amines.
• a process for hardening photographic light-sensitive protein layers and photographic auxiliary protein layers comprising forming a mixture containing photographic protein and as a hardening agent a water-soluble bisulfite of a member selected from the group consisting of polyacrolein and copolymers of acrolein containing at least 50 mol. percent acrolein while maintaining the pH of the mixture between 4 and 6, casting said mixture on a support at a pH of between 4 and 6 and subsequently raising the pH of the cast mixture to above 7 whereby hardening is effected.
• A- process for hardening photographic light-sensitive gelatin layers and photographic auxiliary gelatin layers which comprises forming a mixture containing photographic gelatin and from 0.5 to 4 percent by weight based on dry weight of gelatin of a hardening agent selected from the group consisting of polyacrolein and copolymers of acrolein with a monomer selected from the group consisting of acrylonitrile, acrylic acid, acrylic acid ester, acrylamide, styrene and vinylacetate containing at least 50 mol percent acrolein while maintaining the pH of the mixture between 4 and 6, casting the mixture on a support at a pH between 4 and 6 and subsequently raising the pH of the cast mixture to above 7 whereby hardening is effective.
• a hardening agent selected from the group consisting of polyacrolein and copolymers of acrolein with a monomer selected from the group consisting of acrylonitrile, acrylic acid, acrylic acid ester, acrylamide, styrene and vinylacetate containing at
• copolymers of acrolein are copolymers with a monomer selected from the group consisting of acrylonitrile, acrylic acid, acrylic acid ester acrylamide, styrene and vinylacetate.
• a process for hardening photographic gelatin layers which comprises (a) mixing at a pH value of between 4 and 6 an aqueous casting solution for the photographic gelatin layer with an aqueous solution of a water soluble bisulfite compound of a member selected from the group consisting of polyacrolein and copolymers of acrolein which contain at least 50 mol percent acrolein with a monomer selected from the group consisting of acrylonitrile, acrylic acid, acrylic acid esters, acrylamide, styrene and vinylacetate, the bisulfite compound being present in an amount of 0.5 to 4% by weight, based on the dry weight of gelatin;

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• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

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Citations (4)

• 0
  • BE BE624108D patent/BE624108A/xx unknown
• 1961
  • 1961-10-28 DE DEA38697A patent/DE1156649B/de active Pending
• 1962
  • 1962-10-16 CH CH1213062A patent/CH422509A/de unknown
  • 1962-10-18 GB GB39483/62A patent/GB974317A/en not_active Expired
  • 1962-10-19 US US231819A patent/US3226234A/en not_active Expired - Lifetime

Patent Citations (4)

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