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
  • G03C1/91—Photosensitive materials characterised by the base or auxiliary layers characterised by subbing layers or subbing means

Definitions

• the present invention relates to photographic emulsions on substrates having a subbing or priming layer thereon.
• Typical photographic supports comprise a base material (e.g., polyester, cellulose triacetate, or paper) with a subbing layer on at least one surface to assist in the adherence of the gelatin layers, including the emulsion layers, to the base.
• base material e.g., polyester, cellulose triacetate, or paper
• subbing layer on at least one surface to assist in the adherence of the gelatin layers, including the emulsion layers, to the base.
• Conventional subbing layers are described in U.S. Patent Nos. 3,343,840, 3,495,984, 3,495,985 and 3,788,856.
• the present invention relates to photographic elements having at least one silver halide emulsion layer over a substrate, where the substrate has at least one polymeric surface to which is adhered a layer comprising a gelled network of inorganic particles, preferably inorganic oxide particles.
• the present invention relates to photographic elements. These elements comprise a substrate having at least one silver halide emulsion layer on a surface thereof. A surface with an emulsion thereon is hereinafter referred to as a major surface of the substrate.
• the silver halide emulsion generally comprises silver halide grains (also referred to as crystals or particles) carried in a water­ penetrable binder medium of a hydrophilic colloid. It has been found according to the practice of the present inven­tion that the use of a gelled network of inorganic parti­cles, preferably oxides, as a layer on a polymeric surface provides an excellent subbed (or primed) substrate for photographic emulsions.
• this gelled particulate layer is capable of providing one or more excellent properties to the photographic element including, but not limited to antistatic properties, ease of coatabil­ity of the particulate layer, photoinertness (harmless to the photographic emulsion and its properties), adhesion (both wet and dry, to both the substrate and the emulsion layers), and reduction in specular reflectance (i.e., antihalation properties).
• the substrates of the invention may comprise any material having at least one polymeric surface which is to be used as the major surface of the substrate.
• the finished emulsion is coated on a suitable support.
• Supports which can be used include films of syn­thetic polymers such a polyalkyl acrylate or methacrylate, polystyrene, polyvinyl chloride, partial formalation poly­vinyl alcohol, polycarbonate, polyesters such as polyethyl­ene terephthalate, and polyamides, films of cellulose derivatives such as cellulose nitrate, cellulose acetate, cellulose triacetate, and cellulose acetate butyrate, paper covered with ⁇ -olefin polymers or gelatin (a natural polymer), for example, and synthetic papers made of poly­ styrene; that is, any of transparent or opaque support commonly used in photographic elements can be used.
• syn­thetic polymers such as polyalkyl acrylate or methacrylate, polystyrene, polyvinyl chloride, partial formalation poly­vinyl alcohol, polycarbonate, polyesters such as polyethyl­ene terephthalate, and polyamides
• films of cellulose derivatives
• Primed polymeric substrates are also useful, including gelatin­primed polymers (e.g., gelatin on poly(ethylene tere­phthalate)), and poly(vinylidene chloride) copolymers or polyester.
• gelatin e.g., gelatin on poly(ethylene tere­phthalate)
• poly(vinylidene chloride) copolymers or polyester This includes polymeric materials loaded with pigments and particulates such as titania to improve the white background of the image and to provide antihalation or other sensitometric effects.
• the substrates of the invention may be used with any type of photographic silver halides including, but not limited to silver chloride, silver bromide, silver chloro­bromide, silver iodochlorobromide, silver bromoiodide and silver chloroiodide grains, which may be in any of the many available crystal forms or habits including, but not limited to cubic, tetrahedral, lamellar, tabular, orthorhombic grains, etc.
• Soluble silver salts and soluble halides can be reacted by methods such as a single jet process, a double jet process, and a combination thereof.
• a procedure can be employed in which silver halide grains are formed under the presence of an excess of silver ions (a so-called reverse mixing process).
• a so-called controlled double jet process can also be employed in which the pAg of the liquid phase wherein the silver halide is formed is kept constant.
• Two or more silver halide emulsions which have been prepared independently may be used in combination with each other.
• Soluble salts are usually removed from the silver halide emulsion after the precipitate formation or physical ripening of the silver halide emulsion.
• a noodle water-washing method can be employed in which the soluble salts are removed by gelling the emulsions.
• a flocculation method utilizing inorganic salts containing polyvalent anions, anionic surface active agents, anionic plymers or gelatin derivatives can also be used.
• the silver halide emulsions are usually chemi­cally sensitized. This chemical sensitization can be carried out, for example, by the methods as described in H. Frieser ed., Die Unen der Photographischen Sawe mit Silverhalogeniden , Akademische Verlagsgesellschaft, pp. 675-734 (1968).
• a sulfur sensitization method using sulfur-containing compounds capable of reacting with active gelatins and silver e.g., thiosulfates, thioureas, mercapto compounds, and rhodanines
• a reduction sensitization method using reducing substances e.g., stannous salts, amines, hydrazine derivatives, formamidinesulfinic acid, and silane compounds
• a noble metal sensitization method using noble metal compounds e.g., gold complex salts, and metal complex salts of Group VIII metals, such as platinum, rhodium, iridium, and palladium, of the Periodic Table
• noble metal compounds e.g., gold complex salts, and metal complex salts of Group VIII metals, such as platinum, rhodium, iridium, and palladium, of the Periodic Table
• the sulfur sensitization method is described in detail, for example, in U.S. Patent Nos. 1,574,944, 2,410,689, 2,278,947, 2,728,668 and 3,656,955; the reduction sensitization method, in U.S. Patent Nos. 2,983,609, 2,419,,974 and 4,054,458; and the noble metal sensitization method, in U.S. Patent Nos. 2,399,083, 2,448,060 and British Patent No. 618,061.
• photographic emulsions which are used in the present invention may be incorporated various compounds for the purpose of, e.g., preventing the formation of fog during the production, storage or photographic processing of the light-sensitive material, or stabilizing photographic per­formance. That is, many compounds known as antifoggants or stabilizers, such as azoles (E.G., benzothiazolium salts, nitroimidazoles, nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzothia­zoles, mercaptobenzimidazoles, mercaptothiadiazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, and mercaptotetrazoles, (particularly 1-phenyl-5-mercaptotetra­zole), mercaptopyrimidines, mercaptotriazines, thioketo compounds (e.g., oxazoline
• the photographic emulsion layers of the light-­sensitive material of the present invention may contain polyalkylene oxide or its derivatives (e.9., ethers, esters and amines), thioether compounds, thiomorpholines, quaternary ammonium salt compounds, urethane derivatives, urea derivatives, imidazole derivatives, 3-pyrazolidones, hydroquinone or its derivatives, and the like for the pur­pose of increasing sensitivity or contrast, or accelerating development.
• polyalkylene oxide or its derivatives e.9., ethers, esters and amines
• thioether compounds e.9., ethers, esters and amines
• thiomorpholines quaternary ammonium salt compounds
• urethane derivatives urea derivatives
• imidazole derivatives imidazole derivatives
• 3-pyrazolidones hydroquinone or its derivatives
• binders or protective colloids to be used in the emulsion layers and intermediate layer of the light­sensitive material of the present invention it is advan­tageous to use gelatins.
• other hydrophilic colloids can be used.
• proteins such as gelatin derivatives, graft polymers of gelatin and other polymers, albumin, and casein, sugar derivatives such as cellulose derivatives (e.g., hydroxyethyl cellulose, carboxymethyl cellulose, and cellulose sulfate), sodium alginate, and starch derivatives, and various synthetic hydrophilic polymeric substances, homopolymers or copolymers, such as polyvinyl alcohol, polyvinyl alcohol partial acetal, poly(N-vinyl)pyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinyl imidazole, and polyvinyl pyrazole can be used.
• the light-sensitive material of the present inven­tion is particularly effectively used as a black-and-white reflection light-sensitive material which is to be subjected to rapid processing.
• it can be used as an X-ray recording light-sensitive material, a photomechanical process light-sensitive material, a light-sensitive material to be used in a facsimile system, etc., and further, as a multilayer, multicolor photographic light-sensitive material having at least two different spectral sensitivities.
• the multilayer, multicolor photographic material usually comprises a support, and at least one red-sensitive emulsion layer, at least one green-sensitive emulsion layer and at least one blue-sensitive emulsion layer on the support.
• the order in which the above layers are arranged can be chosen appropriately.
• the red-sensitive emulsion layer contains cyan dye forming couplers
• the green-sensitive emulsion layer contains magenta dye forming couplers
• the blue-sensitive emulsion layer contains yellow dye forming couplers.
• other combina­tions can be employed. Even in the case of the multilayer, multicolor photographic material, the effects of the present invention are exhibited significantly in a reflection light-sensitive material.
• Spectral sensitizing dyes may be used in one or more silver halide emulsions useful on the subbed substrates of the present invention. These sensitizing dyes are well known in the art to increase the sensitization of silver halide grains to various portions of the electromagnetic spectrum such as the ultraviolet, blue, green, yellow, orange, red, near infrared, and infrared. These dyes may be used singly or in combination with other dyes to sensitize the emulsions.
• the substrate of the invention bears a coating comprising a continuous gelled network of inorganic metal oxide particles.
• the particles preferably have an average primary particle size of less than about 500 or 200 ⁇ .
• continuous refers to covering the surface of the substrate with virtually no straight-line penetrable discontinuities or gaps in the areas where the gelled network is applied.
• the layer may be and usually is porous, without significant straight-line pores or gaps in the layer.
• gelled network refers to an aggregation of colloidal particles linked together to form a porous three-dimensional network. Generally all of or the majority of linkages are from the material of the particles, but some binder may also be present.
• porous refers to the presence of voids between the inorganic metal oxide particles created by the packing of the metal oxide particles.
• primary particle size refers to the average size of unagglomerated single particles of inorganic metal oxide.
• particle includes spherical, non-spherical, and fibrillar particulate arrangements.
• the coating should be thicker than a monolayer of particles.
• the coating comprises a thickness equal to or greater than three average particle diameters and more preferably equal to or greater than five particle diameters.
• the articles of the invention comprise a substrate which may be transparent, translucent, or opaque to visible light having at least one polymeric surface, and have formed thereon a coating in the form of a continuous gelled network of inorganic oxide particles.
• the coated article When the coating is applied to transparent substrates to achieve increased light trans­missivity, the coated article preferably exhibits a total average increase in transmissivity of normal incident light of at least two percent and up to as much as ten percent or more, when compared to an uncoated substrate, depending on the substrate coated, over a range of wavelengths extending at least between 400 to 900 nm.
• An increase in light transmission of two percent or more is generally visually apparent and is sufficient to produce a measurable increase in energy transmissivity when the coated substrate is used.
• An increase in transmissivity is also present at wavelengths into the infrared portion of the spectrum.
• the gelled network is a porous coating having voids between the inorganic oxide particles. If the porosity is too small, the antireflectance may be reduced. If the porosity is too large, the coating is weakened and may have reduced adhesion to the substrate.
• the colloidal solution from which the gelled network is obtained is capable of providing porosity of about 25 to 70 volume percent, preferably about 30 to 60 volume percent when dried. The porosity can be determined by drying a suffi­cient amount of the colloidal solution to provide a dried product sample of about 50 to 100 mg and analyzing the sample using a "Quantasorb" surface area analyzer available from Quantachrome Corp., Syosett, NY.
• the voids of the porous coating provide a multi­plicity of subwavelength interstices between the inorganic particles where the index of refraction abruptly changes from that of air to that of the coating material.
• These subwavelength interstices which are present throughout the coating layer, provide a coating which may have a calculated index of refraction (RI) of from about 1.15 to 1.40, preferively 1.20 to 1.30 depending on the porosity of the coating.
• RI index of refraction
• the average primary particle size of the colloidal inorganic metal oxide particles is preferably less than about 200 ⁇ .
• the average primary particle size of the colloidal inorganic metal oxide particles is more preferably less than about 70 ⁇ . When the average particle size becomes too large, the resulting dried coating surface is less efficient as an antireflection coating.
• the average thickness of the dried coating is preferably from about 300 to 10,000 ⁇ , more preferably 800 to 5000 ⁇ and most preferably between 900 and 2000 ⁇ . Such coatings provide good antistatic properties. When the coating thickness is too great, the coating has reduced adhesion and flexibility and may readily flake off or form powder under mechanical stress.
• Articles such as transparent sheet or film materials may be coated on a single side or on both sides to increase light transmissivity, the greatest increase being achieved by coating both sides.
• the process of coating the layer of the present invention comprises coating a substrate with a solution of colloidal inorganic metal oxide particles, the solution preferably containing 0.2 to 15 weight percent of the particles, the particles preferably having an average primary particle size less than about 500 or 200 ⁇ , more preferably less than about 70 ⁇ , and drying the coating at a temperature less than that which degrades the substrate, preferably less than about 200°C, more preferably in the range of 80 to 120°C.
• the coating provides the substrate with an average reduction in specular reflectance of at least two percent over wavelengths of 400 to 900 nm.
• Coating may be carried out by standard coating techniques such as bar coating, roll coating, knife coating curtain coating, rotogravure coating, spraying and dipping.
• the substrate may be treated prior to coating to obtain a uniform coating using techniques such as corona discharge, flame treatment, and electron beam. Generally, no pretreat­ment is required.
• the colloidal inorganic oxide solution e.g., a hydrosol or organosol
• a moderately low temperature generally less than about 200°C, preferably 80-120°C, to remove the water or organic liquid medium.
• the coating may also be dried at room temperature, provided the drying time is sufficient to permit the coating to dry completely.
• the drying temperature should be less than at which the substrate degrades.
• the resulting coating is hygroscopic in that it is capable of absorbing and/or rehydrating water, for example, in an amount of up to about 15 to 20 weight percent, depending on ambient temperature and humidity conditions.
• the colloidal inorganic oxide solution utilized in the present invention comprises finely divided solid inorganic metal oxide particles in a liquid.
• solution includes dispersions or suspen­sions of finely divided particles of ultramicroscopic size in a liquid medium.
• the solutions used in the practice of this invention are clear to milky in appearance.
• Inorganic metal oxides particularly suitable for use in the present invention include boehmite (alpha-Al2O3 ⁇ H2O), tin oxide (SnO2), titania, antimony oxide (Sb2O5), zirconium oxide (ZrO2), cerium oxide, yttrium oxide, zircon (ZrSiO4), silica, and alumina-coated silica as well as other inorganic metal oxides of Groups III and IV of the Periodic Table and mixtures thereof.
• the selection of the inorganic metal oxide is dependent upon the ultimate balance of properties desired. Inorganics such as silicon nitride, silicon carbide, and magnesium fluoride when provided in sol form are also useful
• Examples of commercially available inorganic metal oxides include “Dispural” and “Pural” boehmite available from Condea Petrochemie GmbH, “Catapal” SB, boehmite available from Vista Chemical Co., and “Nalco” ISJ-614, alumina sol, “Nalco” ISJ-611, antimony oxide sol, and “Nalco” ISJ-613, alumina-coated silica sol, available from Nalco Chemical Company.
• the colloidal coating solution preferably contains about 0.2 to 15 weight percent, preferably about 0.5 to 6 weight percent, colloidal inorganic metal oxide particles. At particle concentrations about 15 weight percent, the resulting coating may have reduced uniformity in thickness and exhibit reduced adhesion to the substrate surface. Difficulties in obtaining a sufficiently thin coating to achieve increased light transmissivity and reduced reflec­tion may also be encountered at concentrations above about 15 weight percent. At concentrations below 0.1 weight percent, process inefficiencies result due to the large amount of liquid which must be removed and antireflection properties may be reduced.
• the thickness of the applied wet coating solution is dependent on the concentration of inorganic metal oxide particles in the coating solution and the desired thickness of the dried coating.
• the thickness of the wet coating solution is preferably such that the resulting dried coating thickness is from about 80 to 500 nm thick, more preferably about 90 to 200 nm thick.
• the coating solution may also optionally contain a surfactant to improve wettability of the solution on the substrate, but inclusion of an excessive amount of surfac­tant may reduce the adhesion of the coating to the sub­strate.
• a surfactant include "Tergitol” TMN-6 (Union Carbide Corp.) and “Triton” X-100 (Rohm and Haas Co.).
• the surfactant can be used in amounts of up to about 0.5 weight percent of the solution.
• the coating solution may optionally contain a polymeric binder to aid in adhering the coating to the sub­strate.
• a polymeric binder to aid in adhering the coating to the sub­strate.
• Useful polymeric binders include polyvinyl alcohol, polyvinyl acetate, polyesters, polyamides, polyvinyl pyrrolidone, copolyesters, copolymers of acrylic acid and/or methacrylic acid, and copolymers of styrene.
• the coating solution can contain up to about 20 weight percent of the polymeric binder based on the weight of the inorganic metal oxide particles.
• Useful amounts of polymeric binder are generally in the range of 1 to 15 weight percent. These binders can reduce some of the beneficial properties (e.g., antistatic properties) of the coatings so are not most preferred.
• Sol-gel solution was coated on film substrate using a wire-wound Meyer rod (either #4 or #6) drawn down by hand. Each coated sample was dried for 90 seconds in a 110°C oven. Wetting agent was added in a few cases to improve coating quality. These samples were tested for surface resistivity, yellowness index, and water contact angle.
• Sol-gel samples were coated with an X-ray photo­graphic emulsion under red light using a #24 Meyer rod, drawn down by hand on a glass sheet over a tray of ice (in order to stimulate a chill zone).
• the emulsion was 0.25 micron cubic grains of 64% AgCl and 36% AgBr with a narrow size distribution and was maintained in a constant tempera­ture bath at 40°C.
• Each sample was cured for 5 minutes in a 32.5°C oven. All samples were then aged for one week at ambient temperature.
• Emulsion coated samples were immersed in conventional photographic developer for 3 minutes, then conventional fixer solution for 5 minutes, followed by a 10 minute water wash. The wet samples were then scribed with a razor, rubbed firmly with a fingertip, and checked for loss of adhesion. Samples were graded 0 to 10 (perfect).
• TX2588 (Nalco TiO2 sol, 200 ⁇ particle size) in H20 8.93 g TX2588 + 0.5 g 10% Tergitol TMN-6 41.07 g H2O
• Solution 2.5% Nalco 2326 in anhydrous reagent alcohol.
• Base 122 micron polystyrene, nitrocellulose/gelatin primed.
• Solution 2.5% Nalco 2326 in anhydrous reagent alcohol.
• Base 100 micron PET, PVdC primed, gelatin subbed
• sol-gel solutions formed continuous coatings on the film substrates. When dry, the coatings adhere under firm rubbing with a fingertip. Emulsion coated acceptably over all sol gel samples and adhered during normal handling while dry. Failure was observed in certain samples during the wet adhesion test. These materials could undergo hand development and provide satisfactory images and gain some benefits of the present invention. All samples provided good dry adhesion.
• Binders used RD-977 (vinylidene chloride/ethyl acrylate/itaconic acid terpolymer latex, i.e., "PVdC") BAI (n-butyl acrylate/acrylonitrile/itaconic acid) BAIG (n-butyl acrylate/acrylonitrile/itaconic acid/glycidyl methacrylate) ISOBAM (maleic anhydride/isobutylene copolymer) RLS-375 (urethane) RD-745 (phenolic resin) Acrysol A-3 - Rohm & Haas (acrylic resin) HPAR (acrylic resin) PVA - Moviol 4-98 (polyvinyl alcohol) P-70 -Toray Ind., Inc.
• PVdC vinylene chloride/ethyl acrylate/itaconic acid terpolymer latex, i.e., "PVdC”
• BAI n-butyl
• sol-gel and gelation as they apply to the use of inorganic dispersions of particles in the forma­tion of layers, are well understood in the art.
• Sol-gels as previously described, comprise a rigidized dispersion of a colloid in a liquid, that is the gelled network previously described. Gelation is the process of rigidizing the sol-­gel. This is often accompanied by extraction of the liquid. Gelation, as opposed to pyrolysis, does not necessarily require the addition of heat as room temperatures and normal humidity conditions will allow gelation to occur. These temperatures and humidity conditions will eventually remove sufficient amounts of the liquid for the colloidal particles to become more solid. Heat of course can be useful in speeding up the liquid extraction process as would gas flow directed against or parallel to the sol-gel coating.
• the liquid extracted sol-gel coating (which will generally retain some significant amounts of liquid, e.g., at least 0.1% by weight up to 10% or 15% or more by weight in some cases) can be described in a number of various physical terms which distinguish it from other particulate constructions such as sintered, adhesively bound, or thermally fused particles.
• the association of the particles in a sol-gel system is a continuous sol-gel network which is known to mean in the art that the particles form an inorganic polymer network at the intersection of the particle (e.g., as with silica sol-gels), or an inorganic salt system. Bonding forces such as van der Waals forces and hydrogen bonding can form an important part of the mechanism of particle association.
• These characterizations of sol-gel compositions are quite distinct from the use of polymer binders which form a binding medium to keep particles associated and where the particles themselves do not exert direct bonding forces on one another.
• the size of the colloid particles in the sol-gel is important. Processes where particulates are ball-milled generally produce particles of no less than about 1 micron. Unless a chemical process is used to form the particles of smaller size, which agglomer­ate to effectively form large particles which are then ball-milled to break up the agglomeration, the particle size limit of about 1 micron from physical processing tends to hold true.

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Cited By (23)

Citations (9)

• 1987
  • 1987-06-10 EP EP87305132A patent/EP0250154A3/fr not_active Withdrawn
  • 1987-06-17 JP JP15103787A patent/JPS635338A/ja active Pending

Patent Citations (9)

Non-Patent Citations (3)

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