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
  • G03C1/053—Polymers obtained by reactions involving only carbon-to-carbon unsaturated bonds, e.g. vinyl polymers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/1053—Imaging affecting physical property or radiation sensitive material, or producing nonplanar or printing surface - process, composition, or product: radiation sensitive composition or product or process of making binder containing
  • Y10S430/1055—Radiation sensitive composition or product or process of making
  • Y10S430/106—Binder containing
  • Y10S430/109—Polyester
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/14—Dimensionally stable material

Definitions

• Photographic films for use in the graphic arts should have good dimensional stability so that when several films are overlaid, as is customary in color reproduction, these films will be in register, i.e., in exact correspondence.
• the photographic emulsions are often coated on glass plates.
• hydrophobic film bases e.g., polyethylene terephthlate, have been used for these purposes in place of glass but the base does not solve emulsion shortcomings.
• a desirable characteristic of graphic arts films is their ability to bereduced in image density after development by mechanically removing a portion of the silver image in a controlled fashion by means of a knife, a process commonly referred to as knife etching.
• knife etching a process commonly referred to as knife etching.
• the cohesive and adhesive properties of the binder play a vital role in determining the degree of control possible in knife etching and the freedom from flaking, cracking, or anchorage failure.
• An object of this invention is to provide a unique photographic silver halide emulsion and emulsion layer which retains the advantages of gelatin while overcoming certain disadvantages. Another object is to provide photographic emulsion layers and elements for the graphic arts industry which have improved dimensional stability. Another object is to provide photographic emulsion layers of improved dimensional stability in which the optical density of the developed image remains stable during change from a wet to a dry state. A further object is to prepare such emulsion layers which have improved knife etchability, impact strength, and adherence to a dimensionally stable photographic film base. Still other objects will appear hereafter.
• the improved gelatino-silver halide emulsions of this invention comprise (1) an aqueous phase containing therein as a part of said phase (a) gelatin and (b) a water-soluble polyvinyl pyrrolidone having an average molecular weight of at least 8000 (preferably from 10,000 to 150,000) and (2) a non-aqueous phase dispersed therein of water-dispersible colloidal particles (preferably of an average diameter of less than 400 mp.) of a substantially water-insoluble vinyl addition polymer of an ethylenically unsaturated monomer of molecular weight less than 250, said gelatin, polyvinyl pyrrolidone and Water-insoluble polymer being present in the percentages by weight from 30% to 6% to 30%, and 10% to 55%, respectively, of the total weight of the three polymeric binders. There may be present minor amounts, usually less than 5% of the weight of the three binders, of various emulsion adjuvants, dispersing agents, coating aid
• novel tri-component colloid binder silver halide emulsions can be made in various manners.
• light-sensitive silver halide or a mixture of such halides is precipitated in an aqueous photographic gelatin solution.
• the resulting emulsion or dispersion retains the protective colloid and other properties of the gelatin of photographic grade.
• suitable sensitizers and, if desired, other emulsion adjuvants there are added to the precipitated silver halide emulsion, which can be washed, ripened, etc., there are added suitable sensitizers and, if desired, other emulsion adjuvants, and the emulsion is digested.
• an aqueous solution or dispersion of the polyvinyl pyrrolidone and of the water-insoluble vinyl addition polymer are addede, separately or simultaneously, an aqueous solution or dispersion of the polyvinyl pyrrolidone and of the water-insoluble vinyl addition polymer. After an intimate mixture is obtained, the resulting tricomponent colloid-silver halide dispersion is coated on a suitable support, e.g., a hydrophobic film base, and the coating dried. Additional gelatin can be 1 added along with the other two colloids to provide the required amount of gelatin in the final silver halide emulsion or dispersion.
• the light-sensitive silver halide layer is given a sensitometric exposure through a neutral density wedge, processed by developing, fixing, etc., and the image densities are read on a conventional type of densitometer.
• the unique tricompone-t gelatin/polyvinyl pyrrolidonefiwater-insoluble vinyl polymer silver halide emulsion yields a clear film which is permeable to aqueous developing and fixing solutions as is an allgelatin film and has comparable photosensitometric properties because of the similarity in silver halide grain structure and size distribution.
• mensional and practical photographic handling properties are markedly improved.
• the humidity coefficient of expansion and size change during processing of the light-sensitive silver halide to a silver image is markedly reduced.
• the optical density of the image in passing from the -wet to the dry state is markedly stabilized so that a final dry optical density can be accurately predicted from a wet optical density reading.
• the knife etching character of this binder is greatly improved from that of an all-gelatin film or a film containing gelatin and one of the other two colloid binding agents so that much greater etching control is possible.
• the drying rate of the processed, exposed film is increased, the tendency to curl at low hurnidities reduced, and the impact resistance and anchorage substantially improved.
• an amphoteric dispersing agent preferably an amphoteric alkyliminodicarboxylate or alkylaminomonocarboxylate dispersing agent of the formula:
• RNI-I [CH CH OOOM] p
• R is an alkyl group of 12-18 carbon atmos
• m is or 1
• p is 2-111
• M is a cation selected from the group consisting of hydrogen, sodium, potassium and ammonium.
• the dispersing agent is used in an amount from 0.5% to 15.0% by Weight of the waterinsoluble vinyl polymer.
• Suitable amino acid dispersing agents are disclosed in U.S. Patent 2,816,920, Dec. 17, 1957, and are commercially available. Two of these dispersing agents of particular interest are disodium N-tallow beta-iminopropi-onate'and the disodium salt of N-dodecyl-beta-iminodipropionate. In the case of the former dispersing agent, tallow represents a mixture of the alkyl radicals oleyl, palmityl, stearyl and myristyl in order of decreasing concentration.
• Non ionic as well as cationic surfactants can be used, but best results can be obtained, especially in the case of the panchromatic silver halide emulsions, by means of the amphoteric alkyliminodicarboxylate dispersing agents described above.
• the polyvinyl pyrrolidones useful in the emulsion can vary over a fairly wide range of average molecular weight but have an average molecular weight between 10,000 and 150,000. Higher average molecular weights still bring about improvements in certain characteristics of the film but haze sometimes is encountered as the molecular weight increases beyond the preferred range. With molecular weights below the preferred range, the desirable effects are less pronounced since the lower molecular weight material tends to diffuse out of the emulsion during photographic processing of the coated element.
• a preferred class are the alkyl acrylates and methacrylates, e.g., polymers and copolymers of methyl, ethyl, butyl, ethylhexyl acrylate or methyl and butyl methacrylate.
• acrylic or methacrylic acid can be used in the preparation of useful copolymers. With 'most co-monomers, no more than mole percent of such an acid is used in the polymerization with the other constituents so that the copolymer will'remain water-insoluble.
• vinyl monomers used to prepare water insoluble polymer and copolymer dispersions useful in accordance with this invention are [the vinyl esters such as the acetate, propionate, etc.; the vinyl and vinylidene halides such as yinylidene chloride; styrene and substituted styrenes; the dienes such as another.
• the water-insoluble polymers are free from color-former nuclei or groups.
• acrylates in general are preferable to methacrylates and polyethylene to polyvinylidene chloride polymers and copolymers.
• the vinyl polymers in general, have an average molecular weight above 10,000.
• the particle size of vinyl dispersion is important, since the intended application requires freedom from lightscattering. In general, particle sizes below the wave length of light, i.e., below 400 m would be preferred. This may be controlled by techniques of emulsion polymerization known in the art such as the use of adequate concentrations of surfactants, the mode of stirring, the concentrations of reactants, temperature, rate of additions of monomers, etc.
• a film base support which also has adequate dimensional stability, e.g., polymethylene terephthalates, polystyrene, polycarbonates, e.g., the polycarbonate of 2,2-bis-p-hydroxypheny-l propane, polyethylene terephthalate/isophthalate, etc.
• the polyester films include those prepared from highly polymerized esters of terephthalic acid and at least one glycol of the formula HOCH WCH OH where W is polymethylene or .alkyl-substituted polymethylene of 0 to 8 carbons, e.g., 2,2-dimethylpropylene-1,3 or a cycloalkylene radical of 5 to 6 carbon atoms, e.g., cyclopentyl-1,3, and cyclohexyl-1,4.
• Polymeric films comprising up to 20 mole percent -of aliphatic dioarboxylic acids based on total moles of acids, e.g., succinic,
• the above-described polymers or copolymers may contain a number, e.g., 1 to 12 or more, of ether groups in the polymer chain.
• ether groups may be added as part of ether containing glycol derivatives or formed by side reactions during polymerization.
• the emulsions may becoated on various films and plates composed of glass, metal, e.g., aluminum, various waterproof papers, cellulose derivatives, e.g., cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate-butyrate, and cellulose nitrate; other superpolymers, e.g., nylon, polyvinyl chloride, poly(vinyl chloride 00 vinyl acetate), etc.
• the polymer dispersions used in a preferred embodiment of this invention are prepared in a conventional manner, starting with a polymerizable liquid monomer.
• This monomer is emulsified with water by means of the dispersing agents described above, and subjected to a conventional emulsion polymerization using a free radical initiator, e.g. peroxide or a,or.'-aZ0 bis-(isobutyronitrile).
• a free radical initiator e.g. peroxide or a,or.'-aZ0 bis-(isobutyronitrile.
• Procedure A to follow, there is given a description of the preparation of a particularly preferred dispersion, that of polyethylacrylate.
• a bulk polymerization and prepare the dispersions by dispersing the molten polymer in water in the presence of a dispersing agent, such as is commonly done with polyethylene.
• a 30 inch strip of a coating is scribed with a sapphire microgroove stylus so as to produce, near each end of 'the strip, fiducial marks which will be in close proximity to the fiducial marks of a calibrated Invar plate when the strip and Invar plate are brought into contact with one
• the strip is then conditioned for 24 hours at a constant temperature and humidity and then, while maintained at the same conditions, placed in flat contact with the Invar plate.
• Two Gaertner filar micrometer microscopes having a total magnification of 100 diameters and micrometer least count 2 10- inches, are mounted so that measurements may be obtained by means of a graduated glass scale of distances between the fiducial marks on the coating strips and the corresponding fiducial marks on the Invar plate.
• the Invar plate, microscopes and coating strip are all housed in a conditioning cabinet equipped with arm ports and viewing windows. By vector addition of these distances and the known distance between the fiducial marks on the Invar plate, the distance is determined between the two fiducial marks on the strip at a known humidity. The process is repeated, with 24 hour preconditioning, to determine the distance between the stripss two fiducial marks at another known humidity.
• Invar is a nickel-steel alloy.
• Dimensional stability in terms of processing size change is determined in a very similar manner. Distance between fiducial marks is determined on a coating strip which has been conditioned under constant temperature and humidity for 24 hours. The strip is then conventionally processed and dried, conditioned at the previous constant temperature and humidity for 24 hours, and measured to determine the change in distance between fiducial marks. The processing size change is calculated by dividing this change in distance by the average distance.
• Knife etching is a subjective test wherein the etcher rates various materials on the basis of his ability, by means of a knife, to produce smooth gradations in density from high to low from an area having an original high image density. Chipping, cracking, flaking, adhesive failure etc., would cause a poor rating in terms of knife etchability. 7
• Dry adhesion of emulsion to the support was measured by the common test wherein cross-hatched lines are cut through the emulsion and a piece of pressure-sensitive tape is applied to an emulsion surface and then rapidly pulled off. Removal of a part of the emulsion from the base indicates inferior anchorage. Wet anchorage can be determined similarly after normal photographic processing, by determining the tendency of the wet emulsion to lift off the base when a force is applied tangentially at the edge of the cross hatched lines.
• Curl was measured by determining the weight required to restore a 10 x 12" sheet of film conditioned at 20% RH. and 75 F. to a flat condition.
• PROCEDURE B A 22 liter fluted pot was equipped as described in Procedure A and purged with nitrogen in the same manner. To the pot were added 8 liters of distilled water and 16.7 g. of a high molecular weight polyacrylamide (thermal stabilizer), which was added slowly through a long stem funnel of narow bore and washed in with 2.5 liters of distilled water. The mixture was stirred for 2 to 3 hours at room temperature to effect solution. To the solution of polyacrylamide in the pot were added 667 g. of a 30% by weight aqueous solution of sodium lauryl sulfate which was washed in with 400 ml. of distilled water, 1000 g.
• a high molecular weight polyacrylamide thermo stabilizer
• PROCEDURE C A 22-liter fluted pot was equipped as described in Procedure A and purged with nitrogen in the same manner.
• a solution of high molecular weight polyacrylamide (thermal stabilizer) was prepared as described in Procedure B.
• To the solution of polyacrylamide in the pot were added 667 g. of a 30% by weight aqueous isopropanol solution of a surfactant of the formula 0 a e 0 H3) 2C Hz-C o H ng- 001120112) no SOBNa which was washed in with 400 ml. of distilled water.
• a two stage polymerization was carried out as described in Procedure A except that butyl acrylate was used in place of ethyl acrylate.
• the composition by weight of the dispersion made by this procedure is 30% polybutyl acrylate and 1.2% polyether sulfate surfactant.-
• PROCEDURE D Procedure C was essentially repeated except that 800 g. of a 25% by weight aqueous solution of Tamol 731 (.registered trade name, Rohm & Haas, defined by Haynes, Chemical Trade Names and Commercial Synonyms, 2nd edition, 1955, Van Nostrand and Co., New York, as the sodium salt of a carboxylated polyelectrolyte) which was washed in with 267 ml. of distilled water was used in place of the sodium salt of a polyether sulfate surfactant.
• a two-stage polymerization was carried out as described in Procedure A except that .methyl methacrylate was used in place of ethyl acrylate.
• the composition by weight of the dispersion made by this procedure is 30% polymethyl methacrylate and 1.2% sodium salt of carboxylated polyelectrolyte.
• distilled water was used in place of the sodium salt of an alkyl aryl polyether sulfate.
• a two stage polymerization was carried out as described in Procedure A except that styrene was used in place of ethyl acrylate and the bath temperature was 80 C. instead of 75 C.
• the composition by weight of the dispersion made :by this procedure is 30% polystyrene and 1.2% sodium stearate.
• PROCEDURE F Procedure A was essentially repeated except that 716 g. of a 28% by weight aqueous solution of a surfactant of the formula which was washed in with 714 ml. of distilled water, was used in place of disodium-N-tallow-fi-iminodipropionate.
• a mixture of monomers consisting of 3500 g. of vinylidene chloride and 1500 g. of 2-ethylhexyl acrylate was used in place of ethyl acrylate.
• PROCEDURE G Procedure A was essentially repeated except that 333 g. of isooctyl phenyl polyethoxy ethanol which was washed in with 1190 ml. of distilled water was used in place of disodium-N-tallow-B-iminodipropionate.
• the composition by weight of the dispersion made by this procedure is 30% polyethyl acrylate and 2% isooctylphenylpolyethoxy ethanol.
• the dispersion thus prepared was allowed to cool slowly to 87", then cooled in cold water and finally ice water to 30 C. It was then filtered through felt to remove any hard residue.
• the composition by weight of the dispersion made by this procedure is 17.7% polyethylene and 4.9% morpholine oleate.
• Example I A photographic emulsion was precipitated and ripened in a conventional way and freed of unwanted soluble salts by a coagulation and wash procedure taught in Example I of Moede, US. 2,772,165.
• the silver halide composition was 96.3 mole percent AgBr and 3.7 mole percent AgI in the presence of 14.7 g. of gelatin per mole.
• the coa-gulated emulsion was redispersed in water in the presence of additional gelatin, digested at elevated temperatures in the presence of conventional sulfur sensitizers, cooled and stabilized with post-sensitization additives common in the art such as additional halide, antifoggants etc.
• Example II Upon coating and evaluation as described in Example I, improvement were obtained, shown in Table II, similar to those Example I except that the successive step increased by the factor of the square-root- 5 balance of certain properties varied with the particular of two.
• the exposed film strips were developed for 3 dispersion used.
• the polystyrene sample had an average particle size determine its sensitometric characteristics: greater than the other polymers.
• Example III y gj g f Sulfate 3% An emulsion was prepared according to the procedure g eslccae of Example I and divided into three parts. To each 68 32 24'() part was added a polyethyl acrylate dispersion prepared 2 according to Procedure A and a solution of polyvinyl g pyrrolidone of varying molecular weights. Evaluation W KT was carried out as described in Example I. Binder commer to ma 6 positions and resulting properties are shown in Table III.
• idone appears to have a quantitative effect favoring an anhydrous Na S O per liter, washed in tap water and intermediate molecular weight, improvements are possible dried in a conventional manner.
• Optical densities of the over a wide range of molecular weights provided the polyfilm strips were read at each exposure step on a Western vinyl pyrrolidone is water soluble and the concentrations Electric RA-110 0C densitometer, the readings being made of latex and gelatin are properly balanced for the parboth at the start of the drying period when the films were ticular polyvinyl pyrrolidone. The haze level was conwet and at the end of the drying peniod.
• the et t -dr sidered undesirable in the coating employing the polydensity changes recorded in the tables correspond to dry vinyl pyrrolidon f m l c l r W ight.
• this haze level may be tive sign for this density change indicates a loss or gain, t l rable. respectively, of density on drying.
• Example I The four emulsions were coated as in Example I exweight would be 55.5//28, gelatin/polyvinyl pyrrolicept that the film base support had coated on the reverse done/dispersed polymer.
• the dispersions used were preside an antihalation backing containing no silver halide pared, respectively, according to Procedures A, C, D, E, 7 but with binder composition and coating weight identical to the emulsion binder. Evaluation as in Example I gave the results shown below in Table IV.
• Example V An emulsion was prepared similar to that in Example I except that a symmetrical thiocarbocyanine ethiodide optical sensitizing dye was added during digestion to render it panchromatic. The emulsion was divided into three portions and an aqueous solution of polyvinyl pyrrolidone and an aqueous dispersion of polyethyl acrylate were added to each portion. The final binder composition of the first portion was identical to that of the first portion of Example II wherein the polyethyl acrylate polymer was dispersed with an amphoteric dispersing agent, disodium-N-tallowabeta-iminodipropionate (Procedure A).
• an amphoteric dispersing agent disodium-N-tallowabeta-iminodipropionate
• the second emulsion portion was the same except that the polyethyl acrylate was dispersed with an anionic surfactant, sodium lauryl sulfate (Procedure B).
• the third emulsion portion was the same except that the polyethyl acrylate was dispersed with a nonionic agent, isooctylphenyl polyethoxyethanol (Procedure G).
• Example II The three emulsions were coated as in Example I except that the polyethylene terephthalate film base support bore only the single copolymeric substratum (i.e., the second substratum containing 0.5 mg/dm. of gelatin was absent), and had good anchorage and gave results similar to Examples I-IV.
• the polyethylene terephthalate film base support bore only the single copolymeric substratum (i.e., the second substratum containing 0.5 mg/dm. of gelatin was absent), and had good anchorage and gave results similar to Examples I-IV.
• Example VI The coating from emulsion portion No. 5 of Example I was essentially duplicated except that the dispersed water-insoluble vinyl polymer used in the present example was polyethylene, prepared as described in Procedure H. This coating, when compared with an all gelatin binder control by processing both films as described in Example I, was found to exhibit less wet-to-dry density change and improved dimensional stability.
• polystyrene resin e.g., polybutyl acrylate and copolymers of ethyl acrylate, butyl acrylate or ethylhexyl acrylate, and acrylic acid containing less than about 10 mole percent of acrylic acid.
• These polymers are physically fairly soft.
• Other polymers are useful equivalents in the practice of this invention but, because of being relatively harder, they are considered to be less desirable materials.
• these polymers listed in order of decreasing physical hardness, are polymethyl acrylate and polyethyl methacrylate.
• the present invention is not limited to the use of a particular film base support as the emulsions may be coated on various films and plates composed of glass, metal, e.g. aluminum, cellulose derivatives, e.g., cellulose acetate, propionate, butyrate, acetate-butyrate, and nitrate; superpolymers, e.g., nylon, polyvinyl chloride, poly- (vinyl chloride co-vinyl acetate), polystyrene and polyesters such as the poly/methylene terephthalates, polycarbonates, e.g., the polycarbonate of 2,2-bis-p-hydroxyphenyl propane, polyethylene terephthalate/isophthalate, etc.
• superpolymers e.g., nylon, polyvinyl chloride, poly- (vinyl chloride co-vinyl acetate), polystyrene and polyesters such as the poly/methylene terephthalates, polycarbonates, e.g.,
• polyester films include those prepared from highly polymerized esters of terephthalic acid and at least one glycol of the formula HOCH WCH OH where W is polymethylene or alkyl substituted polymethylr pentyl-1,3, and cyclohexyl-1,4. Films comprising up to mole percent of aliphatic dicarboxylic acids based on total moles of acids, e.g., succinic, glutaric, adipic, hexahydroterephthalic and sebacic acids in addition to at least 15 mole percent terephthalic acid are also useful.
• the above described polymers may contain a number (e.g., 1 to 12 or more) of ether groups in the polymer chain. Such ether groups may be added as part of ether containing glycol derivatives or formed by side reactions during polymerization.
• auxiliary layers may be employed such as antiabrasion layers and antihalation backing or undercoat layers.
• the emulsions may be modified by the addition of general emulsion sensitizers, e.*g., alkyl thiourea, phenyl isothiocyanate, sodium thiosulfate, and alkyl isothiocyanate; metal compounds e.g., of gold, platinum, palladium, iridium, rhodium, mercury, cadmium etc.; antifogging agents, e.g., Z-mercaptobenzothizole, l-phenyl-S-mercaptotetrazole, benzotriazole, triazindene, tetrazindene and 5- nitrobenzirnidazole; sensitizing dyes; color formers (which might, alternatively, be in the developer solution); hardeners, e.g., formaldehyde and other aliphatic aldehydes, dimethylol urea, trimethylol melamine; chrome alum and other chro
• Photographic requirements of graphic arts emulsions are generally best met by silver halides in which the predominant halide is bromide. Up to 10 mole percent iodide is added to vary the photographic behavior as well as the usual chemical sensitizers and optical sensitizing dyes.
• the unique binder advantages of this invention such as wet-to-dry density stability, knife etchability, impact resistance, dimensional stability, and anchorage to the support are also applicable in varying degrees to other halides over a wide range of compositions including silver chloride, chloro-bromide and iodo chlorobromide emulsions.
• amphoteric dispersing agents used in the panchromatic emulsions in contrast to the anionic and cationic surfactants used in previously disclosed products, do not interfere with dye sensitization.
• a further advantage is the simplicity of the process of this invention; since the additions are in the form of aqueous solutions and dispersions, the process can be carried out simply and economically on a commercial scale with no need for elaborate equipment such as solvent recovery systems.
• Polymers are often incompatible and, therefore, mixtures of two or three polymers cause difficulties where clarity is desired, as in photographic films. There are no reliable rules known in polymer science for predicting when compatibility will occur or what balance of properties the final polymer mixture will have. According to the present invention, however, applicants have provided a mixture of three different polymers and have found them ⁇ to be compatible and to give photographic emulsions having excellent optical clarity as well as other useful photographic and physical properties.
• a photographic gelatino-silver halide emulsion comprising (l) an aqueous phase containing therein as a part of said phase (a) gelatin and (b) a water-soluble polyvinyl pyrrolidone having an average molecular weight of at least 8,000 and (2) a dispersion therein of water-dispersible colloidal particles of a substantially water-insoluble vinyl addition polymer of an ethylenically unsaturated monomer of molecular weight less than 250, said gelatin, polyvinyl pyrrolidone rand water-insoluble polymer being present in the percentages by weight from 30% to 80%, 6% to 30% and 10% to 55%, respectively, of the total Weight of the three polymeric binders.
• colloidal particles have an average diameter of less than 400 mu and an average molecular weight above 10,000.
• polyvinyl pyrrolidone is poly-N-vinyl py-rrolidone having an average molecular weight from 10,000 to 150,000.
• R is an alkyl group of 1218 carbons
• m is one of the numbers 0 and 1
• p is 2-m
• M is a cation selected from the group consisting of hydrogen, sodium, potassium and ammonium.
• a photographic film comprising a film supportbearing an emulsion layer as defined in claim 3.
• a photographic film comprising a dimensionallystable hydrophobic film support bearing on one surface an emulsion layer as defined in claim 3.

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• 0
  • BE BE619938D patent/BE619938A/xx unknown
• 1961
  • 1961-07-10 US US122653A patent/US3252801A/en not_active Expired - Lifetime
• 1962
  • 1962-07-06 GB GB26074/62A patent/GB976222A/en not_active Expired
  • 1962-07-09 FR FR903375A patent/FR1335160A/fr not_active Expired
  • 1962-07-09 DE DE19621302345D patent/DE1302345C2/de not_active Expired

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