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
  • G03C1/76—Photosensitive materials characterised by the base or auxiliary layers
  • G03C1/95—Photosensitive materials characterised by the base or auxiliary layers rendered opaque or writable, e.g. with inert particulate additives
• • 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
  • G03C1/32—Matting agents
• • 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
  • G03C1/76—Photosensitive materials characterised by the base or auxiliary layers
  • G03C1/7614—Cover layers; Backing layers; Base or auxiliary layers characterised by means for lubricating, for rendering anti-abrasive or for preventing adhesion

Definitions

• the present invention relates to a silver halide photographic material having a support, at least one light-sensitive silver halide emulsion layer and at least one outer light-insensitive layer comprising a dispersion of polymer particles as matting agents.
• the invention relates to a method of producing polymer particles and more particularly to the production of polymer particles having a narrow particle size distribution.
• water-insoluble matting agents have been used in top or back hydrophilic layers of silver halide light-sensitive materials to prevent adhesion when materials are stored in rolls, cartridges or cassettes in conditions of relatively high humidity and temperature, to prevent electrostatic charges by reducing the area of contact of the photographic material, to prevent the formation of Newton's rings during printing and enlargement, or to decrease the occurrence of scratches during storage or packing of the photographic material.
• matting agents insoluble in neutral or acidic solutions and soluble in alkaline medium have been described in the art.
• alkali-soluble matting agents consisting of methacrylic acid - methylmethacrylate copolymers have been described in US 2,391,181, US 2,992,101, US 3,767,448, US 4,142,894, and in GB 878,520, and copolymers of styrene and ⁇ , ⁇ -ethylenically unsaturated carboxy containing monomers have been described in GB 1,055,713.
• Such matting agents are incorporated in the photographic layers in the form of discrete particles by dispersing a solution of the matting agent in a water-insoluble organic solvent in an aqueous gelatin solution, eliminating the organic solvent, and then introducing the obtained dispersion into the coating composition of the photographic layer.
• Alkali-soluble matting agents consisting of methacrylic acid - ethylmethacrylate copolymers containing from 20 to 50 % by weight of methacrylic acid have been described in US 4,447,525 and in EP 370,405. These copolymers dissolve in high concentrations in high volatile organic solvent such as ethylacetate, a solvent which can be easily removed by evaporation from the dispersion of the polymer in aqueous gelatin.
• the matting agents are characterized by the average particle sizes (APS) of their discrete particles and in the patents there are teachings on how to control the APS in the process of synthesis thereof.
• APS average particle sizes
• PSD particle size distribution
• This distribution can be well represented, on Cartesian axis having the relative percentage on ordinate and the particle size on abscissa, by a Gaussian distribution curve.
• Processes described in the art for the synthesis of matting agent dispersions may result in the formation of huge particles exceeding 10 ⁇ m of diameter.
• the presence of such huge particles of matting agents may cause undesirable side effects such as disturbance of uniform coating of the photographic material and disturbance of the distinct layer relationship of a plurality of superposed layers of the photographic material.
• a method comprising carrying out a bulk polymerization followed by a suspension polymerization; a method comprising partly dissolving a polymer in a monomer to provide a dispersion liquid which is then subjected to suspension polymerization; suspension polymerization methods using various suspension stabilizers having strong surface activity, using finely-divided inorganic particles which are slightly dissolved in water or using such suspension stabilizers and inorganic particles in combination; micro suspension polymerization methods in which the liquid particles of monomer are stabilized by high concentration of suspension stabilizer in water; emulsion polymerization methods in which polymerization takes place through micelles; seed emulsion polymerization in which small polymer particles are used as seeds or core particles; and the like.
• DE 4,001,784 discloses a color photographic material having coated thereon two additional light-insensitive layers A and B, B being further from the base than A.
• Layer B comprises, inter alia, an alkali soluble matting agent having an average particle size of from 0.5 to 8 ⁇ m, and an alkali insoluble matting agent having an average particle size of from 0.5 to 10 ⁇ m.
• the present invention relates to a silver halide photographic material having at least one light-sensitive layer coated on a support base and at least one outer light-insensitive layer comprising polydispersed alkali soluble polymer particles and monodispersed alkali insoluble polymer particles having an average particle size of from 1 to 10 ⁇ m wherein at least 95% by number of said polymer particles have a diameter within ⁇ 15% of the average particle size.
• the present invention relates to a process for the production of monodispersed acrylic polymer particles having an average diameter of from 1 to 10 ⁇ m wherein at least 95% by number of said polymer particles have a particle size within ⁇ 15% of the average particle size, comprising the steps of:
• the present invention relates to a process for the production of monodispersed acrylic polymer particles having an average diameter of from 1 to 10 ⁇ m wherein at least 95% by number of said polymer particles have a particle size within ⁇ 15% of the average particle size, comprising the steps of:
• hydrophilic organic solvents in which the process of the present invention can be performed are aliphatic alcohols having from 1 to 10 carbon atoms, such as, for example, methanol, ethanol, propanol, isopropanol, butanol, t-butanol, pentanol, neopentanol, cyclohexanol, octanol, and the like. These organic solvents can be used alone or in combination each other.
• the choice of the most suitable hydrophilic organic alcohol can depend on the solubility properties of the monomer employed for the production of the polymer particle and on the polymer so obtained.
• the hydrophilic organic solvent is methanol or ethanol.
• acrylic derivatives useful in the process of the present invention are methylacrylate, ethylacrylate, n-propylacrylate, isopropylacrylate, n-butylacrylate, isobutylacrylate, sec-butylacrylate, amylacrylate, hexylacrylate, octylacrylate, 2-phenoxyethylacrylate, 2-chloroethylacrylate, 2-acetoxyethylacrylate, dimethylaminoethylacrylate, benzylacrylate, cyclohexylacrylate, phenylacrylate, 2-methoxyethylacrylate, methylmethacrylate, ethylmethacrylate, n-propylmethacrylate, isopropylmethacrylate, n-butylmethacrylate, sec-butylmethacrylate, terz-butylmethacrylate, amylmethacrylate, hexyl
• the acrylic derivative should be soluble in the hydrophilic organic solvent, but the polymer obtained therefrom should be substantially insoluble.
• soluble it is intended a full solubility of the monomer in the hydrophilic solvent in all proportions.
• substantially insoluble it is intended a solubility lower than 0.1 g/l.
• methylmethacrylate is used.
• Copolymers of the above mentioned acrylic derivatives and other vinyl monomers could also be useful in the process of the present invention.
• co-monomers are, for example, styrene derivatives such as styrene, methylstyrene, ⁇ -methylstyrene and chloromethylstyrene, vinyl esters such as vinyl benzoate, vinylphenyl acetate and vinyl naphthoate, vinyl ethers such as allyl butyl ether, methoxyethyl vinyl ether and phenyl vinyl ether, olefins such as ethylene, propylene, 1-butene and 1-pentene, unsaturated nitriles such as acrylonitrile and methacrylonitrile, vinyl ketones such as vinyl methyl ketone and methoxyethyl vinyl ketone, and vinyl chloride.
• styrene derivatives such as styrene, methylstyrene, ⁇ -methylsty
• poly(methylmethacrylate-co-styrene) is used.
• the weight ratio of the co-monomers is not considered to be relevant to obtain the results of the present invention, good results have been obtained with a MMA/ST weight ratio of from 30/70 to 60/40.
• polymer dispersion stabilizers are homopolymers or copolymers of monomers containing nitrogen atoms or heterocyclic rings having an average number molecular weight in the range of from 20,000 to 60,000.
• monomers are, for example, vinylpyridine, vinylpyrrolidone, N-vinylimidazole, ethyleneimine.
• the polymer dispersion stabilizer is a polyvinylpyrrolidone having an average number molecular weight of from 30,000 to 50,000.
• surface active dispersion co-stabilizers are surface active agents.
• surface active agents are cationic surfactants, such as, for example, alkylamine salts, aminoalcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazolines, quaternary nitrogen salts, etc., anionic surfactants, such as, for example, alkylsulfates, alkyl and aralkyl sulfonates, alkyl phosphates, fatty acid salts, phosphorus derivatives, etc., and non-ionic surfactants, such as, for example, fatty acid amide derivatives, polyhydroxy alcohol derivatives, polyoxyalkyl derivatives, etc.
• the polymerization initiator useful in the process of the present invention is an azo type initiator, such as, for example, 2,2'-azobisisobutyronitrile, or 2,2'-azobis(2,4-dimethylvaleronitrile).
• the reactant concentrations are chosen in accordance with the desired average particle size. As a general rule a higher concentration of monomer causes the production of broader particles, and a higher concentration of stabilizer promotes the formation of smaller particles. The concentration of co-stabilizer slightly affects the particle size only at low concentrations of stabilizer.
• a man skilled in the art can properly choose the right balance of these reaction components to obtain the range of particle size and particle size distribution desired.
• the monomer concentration should range from 0.05 to 0.30, preferably from 0.1 to 0.2
• the stabilizer concentration should range from 0.001 to 0.1, preferably from 0.01 to 0.1
• the concentration of the co-stabilizer should range from 10 ⁇ 4 to 0.01, preferably from 0.001 to 0.01. All concentrations are expressed in terms of grams per grams of hydrophilic solvent.
• the temperature of polymerization is an important parameter in the production of monodispersed polymer particles because, if a variation thereof takes place in the reaction solution, a broad particle size distribution will be obtained, in spite of a proper choice of other parameters (such as reactant concentrations or average molecular weight of stabilizer).
• the problem of temperature control becomes more and more important when large quantities of polymer particles have to be obtained using a large reaction vessel. In this case, a temperature gradient is formed in the reaction vessel, causing a broadening of the particle size distribution.
• a faster stirring speed to ensure an appropriate thermal and mass transfer, promotes the formation of large and polydispersed particles and therefore does not solve the problem.
• the acrylic acid derivative monomer, the polymeric dispersion stabilizer, and the surface active dispersion co-stabilizer are dissolved in the hydrophilic organic solvent contained in a vessel equipped with a condenser, a thermometer and a stirrer. After dissolution, the temperature is raised until reaching the boiling point, and the stirring speed is adjusted to a value lower than 80 revolutions per minute, preferably at about 60 revolutions per minute. After that the polymerization is started by the introduction of the polymerization initiator. The polymerization is conducted for about 12 to 36 hours, preferably 24 hours, and a second addition of initiator can be performed after from 9 to 27 hours, to promote the growth of the preformed particles.
• the dispersion is cooled and the agitation is stopped.
• the polymer particles can be separated by sedimentation, centrifugation or decantation. Thereafter the settled polymer particles are washed, filtered and re-suspended in water or dried.
• the polymer particles obtained with the process of the present invention show an average diameter of from 1 to 10 ⁇ m, preferably of from 3 to 7 ⁇ m, and at least 95% by number, preferably at least 99% by number, show a diameter within ⁇ 15%, preferably within ⁇ 10%, of the average diameter.
• the polymer particles obtained with the process of the present invention can be used for a number of application.
• a preferred application thereof relates to the use as matting agents in photographic elements.
• the present invention relates to a silver halide photographic material having at least one light-sensitive layer coated on a support base and at least one light-insensitive layer comprising polydispersed alkali soluble polymer particles and monodispersed alkali insoluble polymer particles having an average particle size of from 1 to 10 ⁇ m wherein at least 95% by number of said polymer particles have a diameter within ⁇ 15% of the average particle size.
• a matting agent dispersion having an average particle size of from 1 to 10 ⁇ m wherein at least 95% by number of said polymer particles have a diameter within ⁇ 15% of the average diameter can be obtained.
• alkali soluble polymeric matting agents has been widely disclosed in the art, such as, for example, in US 2,391,181, US 2,992,101, US 3,767,448, US 4,142,894, US 4,447,525, GB 878,520 and GB 1,055713.
• useful alkali soluble polymeric matting agents comprise particles of methacrylic acid - ethylmethacrylate copolymers containing from 20 to 50% by weight of methacrylic acid as described in US 4,447,525 or in EP 370,405. Dispersions of these matting agents show an average particle size in the range of from 1 to 10 ⁇ m and a particle size distribution within about ⁇ 50% of the average particle size.
• the matting agents of the present invention are incorporated into the outer layer of the photographic material. They can be for instance incorporated into the surface protective layer coated on the silver halide emulsion layers, or into the backing layer coated on the support base on the side opposite to that containing the light-sensitive layers, or on both sides. It is more preferred, in any case, to incorporate the matting agents of the present invention into outer protective layer. Matting agents are incorporated into the layer under the form of small particles uniformly dispersed therein having an average diameter preferably in the range of from 3 to 6 ⁇ m.
• Matting agents may be either directly dispersed in the photographic layer or may be dispersed in water solutions or in the water dispersions of the photographic layer binding material and then added to the coating composition prior to coating itself. They may also be incorporated in the photographic layer by dispersing a solution of the matting agent in a water-insoluble organic solvent, in an aqueous gelatin solution, eliminating the organic solvent, and then introducing the obtained dispersion into the coating composition of the photographic layer.
• Matting agents are incorporated in a quantity of about 50 to about 600 mg/m2, more preferably from about 150 to about 400 mg/m2 relative to the surface layer.
• the amount of the polydispersed alkali soluble polymeric matting agent ranges from 40 to 250 mg/m2, more preferably from 80 to 150 mg/m2; and the amount of the monodispersed alkali insoluble polymeric matting agent ranges from 10 to 110 mg/m2, preferably from 10 to 50 mg/m2.
• the binding agent of such layer preferably is gelatin, but treated gelatins like the so-called acid or basic gelatins, the gelatins treated with enzymes, gelatin derivatives and modified gelatins can also be used.
• Photographic materials in which the particles of the invention can be used generally comprise at least one light sensitive layer, such as a silver halide emulsion layer, coated on at least one side of a support.
• This layer can be sensitized to a particular range of wavelengths with a sensitizing dye.
• Additional light sensitive layers can be sensitized to a different wavelength range.
• the light sensitive layers can contain or have associated therewith dye-forming compounds or couplers. For example, a red-sensitive emulsion would generally have a cyan coupler associated therewith, a green-sensitive emulsion would generally have a magenta coupler associated therewith, and a blue-sensitive emulsion would generally have a yellow coupler associated therewith.
• Other layers and additives such as antistatic compositions, subbing layers, surfactants, filter dyes, intermediate layers, protective layers, anti-halation layers, barrier layers, development inhibiting compounds, and the like can be present in the photographic element.
• Specific photographic materials in which the polymer particles of this invention specifically are applicable, are light-sensitive photographic color materials such as color negative films, color reversal films, color papers, etc., as well as black-and-white light-sensitive photographic materials such as X-ray light-sensitve materials, lithographic light-sensitive materials, black-and-white photographic printing papers, black-and-white negative films, etc.
• light-sensitive photographic color materials such as color negative films, color reversal films, color papers, etc.
• black-and-white light-sensitive photographic materials such as X-ray light-sensitve materials, lithographic light-sensitive materials, black-and-white photographic printing papers, black-and-white negative films, etc.
• AIBN 2,2'-azobis(isobutyrronitrile)
• the dispersion was left to sediment for 24 hours. After that the clear supernatant was removed and the settled polymethylmethacrylate (PMMA) particles were washed in water.
• PMMA polymethylmethacrylate
• PMMA particles having an average diameter of 4.6 ⁇ m and a standard deviation of 0.32 were obtained. About 95% of polymer particles showed a diameter of from 4 to 5.2 ⁇ m.
• PMMA particles having an average diameter of 3.6 ⁇ m and a standard deviation of 0.3 were obtained.
• About 95% of polymer particles showed a diameter of from 2.8 to 3.8 ⁇ m.
• PMMA particles having an average diameter of 4.66 ⁇ m and a standard deviation of 0.39 were obtained.
• About 95% of polymer particles showed a diameter of from 4.1 to 5.2 ⁇ m.
• PMMA particles having an average diameter of 6.1 ⁇ m and a standard deviation of 0.98 were obtained. About 95% of polymer particles showed a diameter of from 5.2 to 7.2 ⁇ m. The same reaction was performed in a 6-liter vessel giving the same results.
• Example 2 The same procedure of example 1 was used in a 1-liter flask by employing 67 grams of a methylmethacrylate (MMA) and styrene (ST) mixture in a MMA/ST weight ratio of 45/55. Poly(MMA-co-ST) particles having an average diameter of 3 ⁇ m and a standard deviation of 0.28 were obtained. About 99% by number of polymer particles showed a diameter of from 2.8 to 3.2 ⁇ m.
• MMA methylmethacrylate
• ST styrene
• a set of silver halide photographic films has been coated consisting of a cellulose triacetate support, a red-sensitive silver halide emulsion layer comprising a cyan-dye forming coupler, a green-sensitive silver halide emulsion layer comprising a magenta-dye forming coupler, a blue-sensitive silver halide emulsion layer comprising a yellow-dye forming coupler and an outer gelatin layer.
• the resulting photographic films were evaluated according the following tests.
• the samples were cut into pieces measuring 2m x 35mm and fixed on a plastic core having a diameter of 5cm at a temperature of 21°C and 50% relative humidity. At the opposite side a weight of 334 grams was bound to obtain a uniform draught and a uniform rolling up of the film on the core. The samples were completely rolled on the core and the end was fixed with adhesive tape. The resulting samples were conditioned for 5 days at 50°C and 75% relative humidity, after that they were allowed at room temperature for two hours. These samples were evaluated by unrolling them and by listening carefully to the noise produced in the points inside the coils where stickiness took place. At the end of the unrolling procedure the film surface was investigated to evaluate the percentage of glazing surface. All the samples were rank-ordered as far as noise and glazing surface are concerned, and the mark 1 was given to the best sample and 12 to the worst. The test was repeated for three times and the final result was the average of the three evaluations.
• Each sample was cut into 24 pieces measuring 6cm x 3.5cm. The resulting samples were conditioned at 24°C and 90% relative humidity for at least 15 hours. With the samples six couples of film having the emulsion layer against the emulsion layer and six having the emulsion layer against the backing layer were prepared. Each couple of samples was loaded with a weight of 1.5Kg for 15 hours at 24°C and 90% relative humidity. At the end the force necessary to detach every couple of samples was measured and the final result was the average of the six measurements.
• Granularity evaluation of the samples showed that samples 7 and 8 of the present invention had the best performance relative to the comparison examples.
• Granularity measurements were conducted by scanning the surface of the sample with a microdensitometer having a circular aperture of 48 ⁇ m.
• the monodispersed alkali insoluble polymer particles obtained with the process of the present invention in combination with polydispersed alkali soluble polymer particles can improve both stickiness and granularity of a silver halide photographic material.

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• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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• 1993
  • 1993-02-08 EP EP93101906A patent/EP0610522B1/de not_active Expired - Lifetime
  • 1993-02-08 DE DE1993624564 patent/DE69324564T2/de not_active Expired - Fee Related

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