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

Definitions

• the invention relates to a method for hardening photographic gelatin layers and a hardening agent for gelatin layers.
• gelatin layers swell with water and have a low mechanical strength when swollen. For this reason, they are usually hardened using suitable hardening agents. These hardening agents crosslink the gelatin molecules with each other and thereby reduce the water absorption or swellability of the layer, increase the melting point and improve the mechanical strength of the gelatin layer. Hardened gelatin layers are above all resistant to the photographic treatment baths.
• Known hardening agents for gelatin include chromium (III) salts, aldehydes, dialdehyde polysaccharides, polyfunctional epoxides, aziridines, polyfunctional vinyl compounds, triacryl formal, substituted dichloro-s-triazines and others in Chap. 2 of the book "The Theory of the Photographic Process” by T. H. James (London, 1977).
• the hardening agents are either added to the gelatin-containing solutions before processing or they are applied as a separate solution to the gelatin layer already on a carrier. In the second case, the hardening agents diffuse into the gelatin layer, where they react with the peptide chains. Both methods can also be used in the Are combined with one another in such a way that part of the hardening agent is added to the gelatin solution and another part is subsequently applied to the layer.
• Chromium salts are so reactive that a gelatin solution added to them shows an increase in viscosity during processing, which makes processing more difficult and may also be limited in time.
• Still other hardening agents are not sufficiently resistant to diffusion and change the hardening state of adjacent layers during storage, or they cannot be used freely for health reasons, such as divinyl sulfone.
• Each hardening agent known hitherto has one or the other disadvantage and does not have the wide range of possible uses, as is particularly desirable in the case of auxiliary gelatin layers which are applied to a support prior to emulsionation and are later in contact with the actual photographic layers.
• the main disadvantage is that the reaction of most hardening agents with gelatin is too slow and further processing of the coated material is often only possible after days or weeks of intermediate storage.
• Chemical Abstract No. 82 608 u and SU-A-176 182 disclose the use of mixtures of a substituted 1,3,5-triazine, formaldehyde and chromium acetate for hardening gelatin-containing layers.
• the object of the invention is therefore a method for curing of gelatin layers and a hardening agent that does not have the disadvantages described.
• the hardener mixture to be added for hardening the gelatin-containing solution consists of a substituted 1,3,5-triazine and formaldehyde and is prepared at least one hour before addition to the gelatin-containing solution to be hardened.
• the substituted triazine and the formaldehyde of the solution are preferably mixed in a ratio of 1: 0.1 to 1: 0.7.
• the gelatin solution mixed with the hardener combination is then processed in the usual manner and without further delay.
• All common application and dosing processes can be used, such as cascade casters, slot casters, roller application processes, gravure processes or also sipping and dipping processes, if necessary with subsequent airbrush equalization.
• the hardening agent combination according to the invention is used with particular advantage in auxiliary layers containing gelatin, which are known, for example, as adhesive layers, anti-curvature layers, protective layers or antistatic layers, because after drying and a brief thermal shock these are already hardened to such an extent that further coating is possible.
• auxiliary layers containing gelatin which are known, for example, as adhesive layers, anti-curvature layers, protective layers or antistatic layers, because after drying and a brief thermal shock these are already hardened to such an extent that further coating is possible.
• the curing agent combination according to the invention can also can be used in all photographic emulsions. It can also be used together with other known curing agents, provided that these are not undesirable for general or photographic reasons. Suitable additional curing agents can be chromium salts, dialdehyde compounds, aziridine compounds or vinyl sulfone derivatives.
• the gelatin layer to be hardened can also contain the usual additives, for example wetting agents, plasticizers, antistatic substances, matting agents, dyes and others.
• an aqueous or aqueous-alcoholic solution of the triazine derivative (TAF) is mixed with formaldehyde solution in such a way that the ratio of TAF: formaldehyde is 1: 0.1 to 1: 0.7.
• this mixed solution is added to the gelatin-containing solution in an amount which is an addition of 0.5 to 4% by weight of TAF + formaldehyde, based on gelatin, corresponds.
• a standing time of more than one hour at room temperature is necessary. Any longer than this time up to several days or weeks is possible, but falling short of this leads to a deterioration in the hardening effect on gelatin.
• the curing agent combinations according to the invention were prepared by adding as much 10% formaldehyde solution to a 2% solution of the TAF in water as the ratio given for H 1, H 2 and H 3, respectively. The mixture was then kept at room temperature for two hours and then the amount given in Table 1 was added to the gelatin solutions.
• the hardening agent-added gelatin solutions were poured onto the pretreated substrate samples in a known manner in such a quantity that an anti-curvature layer with a mass per unit area of 5 g / m 2 resulted after customary solidification with subsequent drying.
• the anti-curvature layer was tested with regard to the melting point and the photochemical properties. The results are also summarized in Table 1.
• Substrate samples (V 1i to V 1p) made of paper coated on both sides with polyethylene were coated with gelatin layers on the pretreated back as in Example 1.
• the curing agents H 4 to H 9 were used in the amounts given in Table 1 and the resulting layers were subjected to the same tests as the layers according to Example 1. The results are also shown in Table 1.
• a conventional b / w photographic emulsion with a gelatin content of 5% by weight e.g. is described in Example 1 of DE Patent Specification 1 140 813, hardener solution according to Table 2 is added and the coating is poured onto a paper support coated on both sides with polyethylene, and the layer is then cooled and dried in a known manner.
• TAF solution 2% by weight TAF solution was mixed with different amounts of formaldehyde solutions (10% by weight), the mixture was left to stand at room temperature for three hours and after this time in the amount of the emulsion given in Table 2 added.
• Samples 2 k and 2 l in which only TAF or only formaldehyde was used as the curing agent, serve as comparative samples within example 2 (see table 2).
• Example 2 The experiments from Example 2 were repeated with the difference that an additional 4 ml of a 2% aqueous urea solution were added to the emulsion samples.
• Formaldehyde solution was mixed in each case in a 2% by weight solution of one of these triazines in a ratio of 0.5 part by weight of formaldehyde to 1 part by weight of a triazine. This mixture was left to stand at room temperature for 3 hours. An amount of this mixture was then added to the gelatin solution of the respective samples such that the amount added in each case was 2% by weight of hardening agent based on gelatin.
• gelatin solutions were rinsed onto the pretreated back, leveled with an air brush and metered so that a coating with a basis weight of about 5 g / m 2 resulted after drying of the layer. Drying took place in the warm air duct at air temperatures rising from 30 ° C to 80 ° C.
• Examples 1 to 4 show that when hardening gelatin-containing layers, a prefabricated mixture of a triazine with formaldehyde can advantageously be used as the hardening agent.
• melting points which were above 45 ° C. were obtained in the fresh test. At least 45 ° C is required to enable quick further processing. After two weeks of natural storage, all layers were boil-proof, a result that could not be obtained by adding the appropriate amounts of triazine and formaldehyde.
• hardener mixtures according to the invention have a wide range of applications and are suitable both for b / w materials and for use in color materials.

Landscapes

• 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)
• Paints Or Removers (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6333862

Family Applications (1)

Country Status (6)

Families Citing this family (5)

Family Cites Families (8)

• 1987
  • 1987-08-17 DE DE19873727293 patent/DE3727293A1/de active Granted
• 1988
  • 1988-06-15 EP EP88109572A patent/EP0303789B1/de not_active Expired - Lifetime
  • 1988-06-15 ES ES198888109572T patent/ES2028187T3/es not_active Expired - Lifetime
  • 1988-06-15 DE DE8888109572T patent/DE3867567D1/de not_active Expired - Lifetime
  • 1988-08-15 JP JP63202039A patent/JP2856741B2/ja not_active Expired - Lifetime
  • 1988-08-16 US US07/232,933 patent/US4944966A/en not_active Expired - Fee Related
  • 1988-08-17 AU AU21116/88A patent/AU612685B2/en not_active Ceased

Also Published As

Similar Documents

Legal Events