Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D275/00—Heterocyclic compounds containing 1,2-thiazole or hydrogenated 1,2-thiazole rings
  • C07D275/04—Heterocyclic compounds containing 1,2-thiazole or hydrogenated 1,2-thiazole rings condensed with carbocyclic rings or ring systems
• • 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
  • G03C1/346—Organic derivatives of bivalent sulfur, selenium or tellurium

Definitions

• Fog depends both on the emulsion and the conditions of. development; for a given emulsion it increases With the degree of development; With constant development conditions, it tends to increase with time, temperature and relative humidity of storage conditions; it is common practice to make accelerated tests of the stability of photo graphic emulsions by storage at increased temperature or humidity, or both. It is, of course, desirable to have emulsions as stable as possible under the conditions of high temperature and humidity which may occur in tropical climates, for example.
• Fog usually appears over the 1 whole area of the sensitive coating, ⁇ but when'severe, it frequently is non-uniform; Fog may also be caused by exposure to chemicals, for example, hydrogen sulfide, and other reactive sulfur compounds, hydrogen peroxide vapor, and strongly reducing materials; While antifoggants and stabilizers may protect, to some extent, agains t such effects, it is normally understood that an antifoggant protects again st spontaneous growth of fog during prolonged storage or storage at high temperaturesand li lmtdities, or during development to maximum contrast and speed,
• anobject of our invention to provide a method for stabilizing photographic silver halide emulsions. Another object is to maintain the sensitivity and fog of photographic silver halide emulsions at or close to initial optimum 'valuesunder keeping conditions of high temperature and humidity. A further-object is toprovide photographic silver halide emulsions containing antifoggarits -or stabilizers. Other objects will become apparent from a consideration of the followiug description and examples.
• D represents the non metallic atoms necessary to complete a monocyclic aromaticgroup of the benzene series, such as benzene or substituted benzenes (i. e., benzene substituted by such radicals as chlorine, bromine, methoxyl, ethoxyl, methyl, ethyl, tc.).
• the fog-inhibitors which we propose to use are added to the emulsion dur n he. pre ets-of. naautas to avoid loss of sensitivity and to inhibit the growth of fog with passage of time under non-ideal conditions of storage.
• a solution of the compounds of the invention when added in suitable concentration, before coating, to unsensitized, chemically sensitized, or. optically sensitized photographic emulsions may not appreciably affect the sensitometric values for sensitivity and fo when measurements are made soon after coating.
• sensitometric measurements are made at appreciable intervals of time, at elevatedtemperatures and dry or somewhat humid conditions, these compounds do stabilize photographic -speed and maintainfog at alow-level.
• Thepreparatiori of silverhalide emulsions involves three separate operations: '(1) the emulsificationand digestion :or ripening of the silver halide, (2) the freeing of the emulsion from excess soluble salts, usually by washing, and (3) the second digestion of after-ripening prior to digestion.
• th sis R er ata- Mas s an ass I Listed below are a number of compounds-coming within the scope of Formula I above which we have found to be particularly advantageous in practicingour inven- 2,8-dihydro-3-oigobenzoisothiazole (av s t -GHI c ll :2,3 si siro-z th aos snz is th aaqls Q SC I ll 2,3-dihydro-2-ethy1-3: oxcheuaoisothiaaole I (MeesflThe Theory of 2-n-butyl-2,3-dihydro-3-oxobenzoisothlaz01e 2-cety1-2,3dihydro-3-oxobenzolsothtazole /N--C ⁇ G H O 2-benzothiazy1-2,3-dihydro-3-oxoheuzoisothiazole (7) s N C
• antifoggant compounds used in our invention have been found particularly useful when employed in conjunction with gelatinosilver-bromiodide emulsions, although they can also be advantageously employed for stabilizing other silver halide emulsions, such as gelatino-silverchloride, bromide, chlorobromide, chlorobromiodide, etc.
• the emulsions can also be chemically sensitized by any of the accepted procedures.
• the emulsions can be digested with naturally active gelatin, or sulfur compounds can be added such as those described in Sheppard U. S. Patent 1,574,944 and ,U.' S. 1,623,499, and Sheppard and Brigham U. S. Patent 2,410,689.
• the emulsions can also be treated with salts of the noble metals such as ruthenium, rhodium, palladium, iridium and platinum, all of which belong to group VIII of the periodic table of elements and have an atomic weight greater than 100.
• Representative compounds are ammonium chloropalladate, potassium chloroplatinate and sodium chloropalladite, which are used for sensitizing in amounts below that which produces any substantial fog inhibition, as described in Smith and Trivelli U. S. Patent 2,448,060, and as antifoggants in higher amounts, as described in Trivelli andSmith US. Patents 2,566,245 and 2,566,263.
• the emulsions can also bechemically sensitized with gold salts as describedin'Waller and Dodd U. S. Patent 2,399,083, or stabilized with gold salts as described in Damschroder U. S. Patent 2,597,85 6 and Yutzy and Leermakers U. S. Patent 2,597,915, Suitable compounds are potassium chloroaurite, potassium aurithiocyanate, potassium chloroauratqauric trichloride and Z-aurosulfobenzothiazole methochlorid'e.
• the emulsions can also be chemically sensitized with reducing agents such as stannous salts (Carroll U. S. Patent 2,487,850), polyamines such as diethylene triamine (Lowe and Jones U. S. Patent 2,518,698), polyamines, such as spermine (Lowe and Allen U. S. Patent 2,521,925), or bis-(fi-aminoethynsulfide and its watersoluble salts (Lowe and Jones U. S. Patent 2,521,926).
• reducing agents such as stannous salts (Carroll U. S. Patent 2,487,850), polyamines such as diethylene triamine (Lowe and Jones U. S. Patent 2,518,698), polyamines, such as spermine (Lowe and Allen U. S. Patent 2,521,925), or bis-(fi-aminoethynsulfide and its watersoluble salts (Lowe and Jones U. S. Patent 2,521,926).
• the emulsions can also be stabilized with the mercury compounds of Allen, Byers and Murray U. S. Patent 2,728,663, Carroll and Murray U. S. Patent 2,728,664, and Leubner and Murray U. S. Patent 2,728,665.
• the stabilizing combinations of our compounds are effective in the presence or absence of optical sensitizing dyes. Since optical sensitizing may affect stability of emulsions with respect to sensitivity, fog and latent image changes, the action of the compounds of this invention is not completely independent of optical sensitizing or other emulsion variables. We have found, however, that both unsensitized emulsions and emulsions sensitized with cyanine or merocyanine dyes, or both, can be treated according to our invention.
• the antifoggant and/or stabilizing action was determined by incubation of the emulsions for one week at a temperature of F. and constant relative humidity (obtained by placing the emulsions'in closed containers, the ambient temperature being about 70 F. and relative humidity about 50-55 percent prior to sealing the containers).
• the etficiency of the various antifoggants was determined by measuring the speed, gamma and fog of the incubated emulsions containing an antifoggant and comparing these measurements with those of the same batch of emulsion before incubation. Also, similar measurements were made with a photographic emulsion containing no antifoggant both before and after incubation.
• test films were exposed on an intensity scale sensitometer and developed for 5 minutes in a developer having the following composition:
• Suitable dispersing agents for the silver halide emulsions stabilized according to our invention comprise gelatin, or other colloids, such as collodion, albumen, celluloseorg'anic derivatives, synthetic resins, etc.
• the optimum amount of fog-inhibiting agent can be determined by making ;the customary tests employed in emulsion making. f course, the optimum amount for a given emulsion will varydepending on the presence of emulsion iaddenda, such as chemical ;sensitizers, optical sensitizers, etc. In general, we have found that from 0.001 to 5.0 g. of fog-inhibting agent per mole of silver halide is suflicient for the purposes of our invention.
• the antifoggants ;of our invention functionadvantageou'sly in acid for alkaline photographic silver halideernul'sions. 7
• certainnitrogen-containing compounds other than those of Formula I above can be used in photographic gsilver halide emulsions, frequently to give antifoggant .or stabilizing effects.
• Such compounds include, for example, "ethylfurfurylidenedicarba'mate, The Furans," A. -C. :S. "Monograph No. 119' (1953), page 374, which can also be named furfurylidenebisurethane (ethyl ester).
• furfurylidenebisurethane ethyl ester
• Other related nitrogencontaining compounds, such as ethylidenebisurethane such as ethylidenebisurethane
• Solution A grams of n-cetylamine were dissolved in 50 cc. of pyridine and 200 cc. of anhydrous carbon tetrachloride with warming.
• Solution B grams of dithiodibenzoylchloride were i "added to 100 cc. of carbon tetrachloride and chlorinewas passed into the mixture until the dithiodibenzoylchloride had dissolved. Nitrogen was then passed into the container holding the solution to remove excess chlorine. The solution was then filtered.
• Solution A was warmed to 55 C. to keep in solution and Solution B was slowly added to Solution A with stirring. The temperature rose to 60 C. and crystals appearing to be pyridine hydrochloride separated. After cooling to ambient temperature, the reaction mixture was poured onto one liter of ice and made acid (with hydrochloric acid) to Congo red. The carbon tetrachloride layer was separated and washed with cold water. The carbon tetrachloride solution was dried over calcium chloride, decolorized with decolorizing carbon and dried over magnesium sulfate. The solution was filtered and concentrated under reduced pressure on the steam bath. The concentrated solution was dissolved in ethyl alcohol, treated once again with decolorizing carbon, filtered and The put in the refrigerator. The desired material crystallized Two solutions were prepared as follows:
• Solution A -7 grams of dithiodibenzoylchloride were added to cc. of carbon tetrachloride and chlorine passed into the mixture until complete solution ensued. Excess chlorine was then removed by passing in nitrogen gas and the solution was filtered.
• Solution B 6 grams of Z-aminobenzothiazole were dissolved in a mixture of 50 cc. of pyridine and cc. of carbon tetrachloride.
• Solution A was-added to Solution B slowly, the temperature rising to 45 C. during the addition.
• the desired product separated immediately as crystalline material.
• the reaction mixture was allowed to stand for an additional 1.5 hours and then filtered.
• the filter cake was washed with 100 cc. of water to remove any pyridine hydrochloride present.
• Thedesired product was recrystallized from dimethyl- 'forin'amid'e, collected on a filter, leached in diethyl ether,
• R represents a member selected from the group consisting of a hydrogen atom, an alkyl group, a benzothiazyl group, a benzoxazyl group, and a pyridyl group and D represents the non-metallic atoms necessary to complete a benzene ring.
• R represents a member selected from the group consisting of a hydrogen atom, an alkyl group, a hen zothiazyl group, a benzoxazyl group, and a pyridyl group.
• R represents an alkyl group containing from l to 4 carbon atoms.
• R represents a member selected from the group consisting of a hydrogen atom, an alkyl group, a henzothiazyl group, a benzoxazyl group, and a pyridyl group
• D represents the non-metallic atoms necessary to complete a benzene ring.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Thiazole And Isothizaole Compounds (AREA)
• Plural Heterocyclic Compounds (AREA)

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Cited By (25)

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Citations (1)

• 0
  • BE BE565380D patent/BE565380A/xx unknown
• 1957
  • 1957-03-08 US US644733A patent/US2870015A/en not_active Expired - Lifetime
• 1958
  • 1958-03-06 FR FR1202249D patent/FR1202249A/fr not_active Expired
  • 1958-03-06 GB GB7200/58A patent/GB884514A/en not_active Expired

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