Production method for photographic emulsion based on silver-halide laminate microcrystals with epitaxial nanostructures
FIELD: chemistry; photographic industry.
SUBSTANCE: invention relates to photographic industry, particularly to technology of silver-halide photographic emulsion preparation. According to the invention the production of photographic emulsion based on silver-halide laminate microcrystals (LMC) with epitaxial nanostructures is started from preparing nuclear emulsion from solution of AgNO3 and KBr. Thereafter, substrate LMC AgBr are derived by adding solution of AgNO3 and KBr in the nuclear emulsion. Annular epitaxial nanostructures containing AgBr/AgCl are formed on the produced LMC AgBr by adding Kl and KCl solutions in reaction mixture. At the final stage, firstly, epitaxial nanostructures are converted by adding solution of KBr into reaction mixture, thereafter the second conversion is carried out by adding small particle emulsion prepared separately and containing AgBr0.98l0.02-AgBr0.90I0.10.
EFFECT: simplification of photographic emulsion preparation with optimal photographic characteristics of light sensitivity, as well as microcrystal dispersion characteristics used in industrially produced photomaterials.
1 cl, 1 tbl, 14 ex
This invention relates to photographic industry and, in particular, to a technology of manufacturing a silver halide photographic emulsions.
Obtaining photographic emulsions containing heteroepitaxial nanostructures on a plate microcrystals of silver halide with a given dispersion characteristics and managed distribution profile of the concentration of the halide ions inside microcrystals, is an important task in the technology of photographic materials. The processes of manufacturing Fotolia (chemical, spectral sensitization and so on), as well as photographic characteristics, such as sensitivity, resolution photographs, largely determined by the dispersion characteristics of the plate microcrystals, halide composition and location of epitaxial structures formed on the substrate emulsion microcrystals (MK).
Photographic emulsions containing heteroepitaxial nanostructures plate on AgBr microcrystals can be obtained in several ways. Thus, in patent US 4,865,962 described a method for converting MK AgHal photographic emulsions, which are as follows: the precipitation of a new phase of AgBr on the surface of each substrate MK AgCl is way to small mixing emulsi is based on AgBr microcrystals and emulsions, containing substrate MK AgCl, and their subsequent joint maturation. In this invention indicates that each of the final emulsion MK AgHal contains 90% or more AgCl, a new phase of AgBr grows near the corners of the substrate MK. For example, the emulsion microcrystals chlorobromide silver or silver bromide in an amount of 0.1 to 7 mol.% relative to the substrate AgCl, having an average equivalent diameter of MK in the range of 0.05-0.1 μm, was mixed with the emulsion of the substrate MK AgCl with a pre-adsorbed tormozili growth. During the conversion and maturation emulsion MK of chlorobromide silver dissolved. Then the reaction reaches equilibrium, there is a new layer halide composition at the corners of each substrate MK and the reaction stops. However, to achieve the result used as the substrate isometric MK AgCl (characterized by low bulestechou), and the complexity of the technology due to the introduction of additional organic compounds Hermosilla conversion.
In the patent US 5723278 at the first stage to obtain the emulsion on the base plate microcrystals (PMK) AgBr way controlled twin crystallization (CDC) with increasing feed rate for an extended period of time are introduced solutions of sodium bromide and nitrogen the number of silver when the value of the pBr=1,2-1,6. After that for some time the reaction mixture was kept under stirring, elevated temperature and in the presence of a solvent. In the second stage, the growth of emulsion MK ensure the supply of additional quantities of reagents. Then, when the value of the pBr=2 is introduced into the reactor solution iodixanol acid. Maintaining the reaction mixture at 180 minutes, add a further quantity of silver nitrate and increasing the feed rate of the reactants, the method of the FTC impose solutions of silver nitrate and sodium bromide. The disadvantage of the above method is the duration of the technological process, low photographic sensitivity.
The closest solution of the present invention the composition of the basic substances and the sequence of execution is a method (patent US 6893811) manufacture of photographic emulsions on the basis of silver halide plate microcrystals with epitaxial nanostructures. At the first stage for producing sound of the emulsion in the reactor containing the aqueous gelatin solution by the method of the CDC, was injected with equimolar quantities of solutions of silver nitrate and potassium bromide. After this has introduced additional amount of potassium bromide and raised the temperature of the reaction mixture to 75°C. Then introduced incremental VC is Tina. After that the FTC method was re-introduced equimolar amount of a solution of silver nitrate and potassium bromide. In the second phase synthesized emulsion containing substrate PMK, as follows: to a reactor containing aqueous gelatin solution was added sound emulsion, modified silicone oil, sulfuric acid and the FTC method was applied to solutions of silver nitrate and bromide potassium. After this was introduced benzoylthiourea sodium. Next to the reactor was added a pre-made small-size emulsion (MRA) AgBrI for further growth MK. The next step is the formation of epitaxial structures. This phase includes the following operations: the obtained emulsion substrate plate MK first cooled to a temperature of 50°C, and then to it was added a solution of KI. The reaction mixture was kept under stirring, then added an aqueous solution of K4[Ru(CN)6]. After the introduction of the complex in the reaction mixture by the FTC method was introduced solutions of sodium chloride and silver nitrate. Then the reactor was added MRE AgBrI containing 3 mol.% of potassium iodide. To the resulting emulsion, washed by ultrafiltration, added gelatine.
The method is performed with sequential technological complexity of each stage: the first stage is repeatedly added the basics what's the ingredients of the reaction mixture, in the second stage using additional ingredients: silicone oil, sulfuric acid, benzoylthiourea sodium, is added separately manufactured small-size emulsion (MRA) AgBrI, in the third stage additionally used metal complex, for example, K4[Ru(CN)6], and also entered separately manufactured, MRA AgBrI. The result PMC iodine-chlorobromide silver are quite large (average spherical diameter d=1,3 μm, an average equivalent diameter d=3,35 μm, the average thickness of the crystal 1,130 μm. Such PMK is excellent for research purposes and are unsuitable for the industrial production of emulsions.
The task of the invention is to simplify the method of making photographic emulsions containing heteroepitaxial nanostructures on plate MK AgHal, using a minimum number of reagents, and getting halide composition of epitaxial nanostructures on the plate substrate of the microcrystals, which provides the optimum photographic emulsion characteristics (sensitivity, valentinetti and others). The invention is also getting photoemulsion MK with dispersion characteristics suitable for use in industrial izgotavlivaemykh fotomature the crystals (average equivalent diameter in the range of 1.0 to 5.0 μm; the coefficient of variation in size in the interval 31-38%, coefficient of grain uniformity in the range of 99-100%).
The problem is solved due to the fact that when performing the method of manufacturing a photographic emulsion on the basis of silver halide plate microcrystals with epitaxial nanostructures, which includes stages: preparation sound of the emulsion by introducing into the aqueous gelatin solution is controlled twin crystallization of aqueous solutions of silver nitrate and potassium bromide with a speed of 15 ml/min and pBr 1,4; receiving substrate plate microcrystals of silver bromide introduction to received sound emulsion of an aqueous solution of silver nitrate, the temperature rise of the reaction mixture to 70°C. and the introduction of its controlled twin crystallization of aqueous solutions of silver nitrate and potassium bromide at a rate of 1 ml/min and pBr 1,2; education epitaxial nanostructures composition AgBr/AgCl on the obtained substrate plate microcrystals of silver bromide by introducing into the reaction mixture an aqueous solution of potassium iodide and an aqueous solution of potassium chloride, and then the aqueous solutions of silver nitrate and potassium chloride with a speed of 0.7 ml/min, optionally conduct primary first converting epitaxial nanostructures introduction in d is Klenow mixture of an aqueous solution of potassium bromide at a rate of 120 ml/min and pBr 1,0, then the secondary conversion epitaxial nanostructures by adding the reaction mixture is separately prepared small-size emulsion, containing microcrystalline structure
AgBr0,98I0,02-AgBr0,90I0,10with a speed of 17 ml/min and pBr 2,5.
This small-size emulsion composition AgBr0,98I0,02-AgBr0,90I0,10prepared by introducing into an aqueous solution of gelatin controlled twin crystallization of equal volumes of solutions of silver nitrate and KBr0,98I0,02-KBr0,90I0,10in the range from 0.1 to 2 M as well As in the formation of epitaxial nanostructures composition AgBr/AgCl on the substrate plate microcrystals of silver bromide aqueous solution of potassium iodide is administered in an amount of 0.1 to 15 ml at a rate of 0.2-120 ml/min
During chemical-photographic processing of the photographic layers on the basis of the MC with the epitaxial structures usually observed rapid increase in the optical density of the veil. The recently proposed approaches for managing halide composition of the epitaxial structures by means of the conversion process could help to overcome the main drawbacks of these systems is low valentinetti and stability during storage. However, due to the very high response speed and complexity of the conversion process, it is problematic to get Amul the pension MK, combining optimum photographic and dispersion characteristics, suitable for use in industrial manufactured materials. Therefore, for a more predictable and managed the process of converting offered to hold it in two stages. At the initial stage of primary conversion since the conversion of MRA AgBrI in one stage leads to fazoobrazovanie in volume and requires the introduction of additional quantities of the reactants, which leads to deterioration of the dispersion and the photographic characteristics of the MK. In the second stage is the conversion of MRA AgBrI when using KBr solution0,98I0,02-KBr0,90I0,10. The presence of iodide can significantly increase the sensitivity of photographic materials mainly by reducing the recombination of photoinduced charge carriers, and the structuring of MK, in addition, makes it possible to consciously control the movement of charge carriers in MK and thereby to optimize the processes of concentration of photolytic silver, which also allows to increase the sensitivity of the photographic material. It is established that a noticeable effect concentration photolytic silver occurs when the concentration of iodide in AgBrI 2 mol.%. The lasting effect of 4 mol.% up to 10 mol.% iodide. In the limit of perhaps aluchemie surface of pure silver iodide. However, since the concentration of iodide in AgBrI 12 mol.% there is a noticeable decrease in the sensitivity of photographic emulsions associated with the inhibition of the development process.
The process of converting a two-step process allows you to vary the composition of sensitizers, which gives the opportunity to avoid long J-aggregates of dye and to control the size of particles of the developed image at the stage of manifestation, providing optimum photographic emulsion characteristics (sensitivity, valentinetti and others).
In the proposed method, the topography of the potential growth phase AgCl is determined by adding the potassium iodide solution. If the amount of potassium iodide is insufficient (less than 0.1 ml) or the feed rate of solution of iodide of potassium is high (more than 120 ml/min), there is not only the angle but also the peripheral epitaxy ribs PMK.
In the case of increasing the amount of potassium iodide solution over 15 ml and decrease the rate of feed of less than 0.2 ml/min is observed epitaxy on large planes, which in turn has an adverse effect on photographic characteristics of the emulsion PMK.
Effective is the introduction of a 0.01 M solution of iodide Calea with a speed of 0.7 ml/min and 10 ml of providing the location of epitaxially the structures at the corners PMK, since their number in this case is limited and they are located at a large distance from each other which increases the efficiency of the photo process at the stage of exposure.
The study of the structure of MK using an electron microscope showed pronounced morphological changes of epitaxial structures, indicating the course of the process of their transformation.
Conversion of the bromide ion source epitaxial AgCl nanostructures leads to changes in their halide composition and is not accompanied by the formation of particles of a new phase. Obtained by the method of converting heteroepitaxial flat AgBr microcrystals with epitaxially structures, converted bromide and iodide ions are more bulestechou, better storage stability and higher sensitivity.
Synthesis sound emulsions
Into the reactor containing the aqueous gelatin solution (0.5 g gelatin per 1000 g of water) and 0.38 g of KBr, thermostated at 40°C, under stirring at the same time the FTC method to introduce 20 ml of 0,29M aqueous solutions of silver nitrate and potassium bromide for 40 sec. After that enter 22 ml of 10% solution of potassium bromide. The temperature of the reaction mixture increased to 75°C. After that enter the extension gelatin 35 g per 250 ml of water, pH is set to 6. Methodology the FTC imposed 1.2 M solutions of AgNO 3and KBr, maintaining the pBr value of 2.64. Set the pH value of 5.7 pAg of 8.8. After that, the emulsion is washed. The dispersion characteristics of the resulting crystals d=0,7 µm, Cv=31%, St=98%.
The receiving substrate emulsion plate MK
Into the reactor containing the aqueous gelatin solution (46 g of gelatin at 1211 g of water) and 1.7 g of KBr, thermostated at 75°C, add 185 g sound emulsions and modified silicone oil (L7602, Nippon Unicar Company, Limited). Then add sulfuric acid to a pH value of 5.5. Under stirring at the same time by the method of the FTC imposed on 67,6 ml of aqueous solutions of silver nitrate and idromassage potassium iodide content of 3 mol.%, supporting E=+0 mV. Within 6 min final speed of the introduction of more elementary 5.1 times. After that enter 2 mg benzylthiocyanate sodium. At the same time outside of the reactor synthesize MRA AgBrI (d 0,01 µm) as follows: FTC method in an aqueous gelatin solution (average molecular weight gelatin 15000 g) to introduce 762 ml of aqueous solutions of silver nitrate and iodobromide potassium iodide content of 3 mol.%. Fine-grain AgBrI emulsion was placed in a reaction vessel and within 120 min potential reaction mixture was -20 mV. After this method, the FTC introduced into the reactor an aqueous solution of potassium bromide and an aqueous solution of silver nitrate in the amount of 131 ml within 30 m is N. The first 20 min potential was +20 mV, the last 10 min +100 mV.
The formation of epitaxial structures
The emulsion obtained with plate substrate MK was cooled to a temperature of 50°C and to it was added 156 ml of 0.5% KI solution. The resulting mixture was stirred 20 min, then added an aqueous solution containing K4[Ru(CN)6] in the amount of 1.0·10-5mol/mol Ag. After this method, the FTC has introduced 140 ml of a solution containing 1.9 grams NaCl, and 80 ml of a solution containing 3.1 g AgNO3. At the same time was obtained MRA AgBrI (d=0.03 µm) as follows: FTC method in an aqueous gelatin solution (weight gelatin 0.84 g) was administered in 50 ml solutions of silver nitrate and idromassage potassium iodide content of 3 mol.%. MRA was added to the reaction vessel. To the emulsion washed by ultrafiltration was introduced incremental gelatin and set to pH 5.8, pAg 8,7.
Example 1 Synthesis sound of the emulsion In the reactor containing the aqueous gelatin solution (10 g of gelatin in 300 g of water) and thermostated at 40°C, under stirring at the same time the FTC method introduced in 100 ml of 0.1 M aqueous solutions of silver nitrate and potassium bromide with a speed of 15 ml/min, while maintaining the pBr value of 1.4. Received sound emulsion composition of AgBr. The average equivalent diameter of microcrystals sound of the emulsion is 70 nm.
aluchemie substrate emulsion plate MK
To the sound of the emulsion was injected 2 ml of 2 M solution of silver nitrate with a speed of 15 ml/min After the temperature of the reaction mixture was increased to 70°C. After 90 min under stirring at the same time by way of the FTC was introduced in 98 ml of 2 M aqueous solutions of silver nitrate and potassium bromide at a rate of 1 ml/min, while maintaining the pBr value of 1.2. The dispersion characteristics of the formed microcrystals composition AgBr - d=1,8 µm, Cv=31%, ST=100%.
The formation of epitaxial structures
In thermostatted at 40°C. the reactor containing 200 ml of emulsion with PMC AgBr at a concentration of silver of 4 g/l, was injected 10 ml of 0,01M potassium iodide solution with a speed of 0.7 ml/min, then was injected 7 ml of 1M KCl solution with a speed of 0.7 ml/min, then with a speed of 0.7 ml/min was applied for 0.1 M solutions of AgNO3and KCl, and the number of input at this stage of silver chloride corresponded to 20 mol. % of AgBr in the original PMK. The dispersion characteristics of the MK composition AgBr/AgCl, d=1,8 µm, Cv=32%, ST=100%.
Converting epitaxial nanostructures
Primary conversion was carried out by introducing into thermostatted at 40°C. the reaction mixture 10 ml of 2M aqueous solution of potassium bromide at a rate of 120 ml/min; the amount of the pBr of the reaction mixture has a value of 1.0. The resulting emulsion was stirred for 10 minutes during this BP is the groups conducted sampling to study the morphological changes. At the stage of secondary conversion in the reaction mixture were added separately prigotovlyaemye small-size emulsion composition AgBr0,96I0,04that was synthesized as follows: in a thermostatted at 40°C. the reactor and the pBr value of 2.5 was placed 300 ml of N2O and 12 g of gelatin and simultaneously filed by the method of controlled twin crystallization in 100 ml of 1 M silver nitrate solution and a KBr0,96I0,04with a speed of 17 ml/min with constant stirring. Characteristics of MK final emulsion d=1,8 µm, Cv=32%, ST=100%.
Other examples of key parameters when implementing the method and characteristics of the microcrystals in the table.
A method of manufacturing a photographic emulsion on the basis of silver halide plate microcrystals with epitaxial nanostructures, comprising the steps:
making sound emulsions by introducing into the aqueous gelatin solution is controlled twin crystallization of aqueous solutions of silver nitrate and potassium bromide with a speed of 15 ml/min and the pBr value=1,4,
receiving substrate plate microcrystals of silver bromide introduction to received sound emulsion of an aqueous solution of silver nitrate, the temperature rise of the reaction mixture and the introduction of its controlled Duhs ruinous crystallization of aqueous solutions of silver nitrate and potassium bromide at a rate of 1 ml/min and the value pBr=1,2,
education epitaxial nanostructures composition AgBr/AgCl on the obtained substrate plate microcrystals of silver bromide by introducing into the reaction mixture an aqueous solution of potassium iodide and an aqueous solution of potassium chloride, and then the aqueous solutions of silver nitrate and potassium chloride with a speed of 0.7 ml/min,
primary conversion epitaxial nanostructures introduction into the reaction mixture an aqueous solution of potassium bromide at a rate of 120 ml/min and the pBr value=1,0,
secondary conversion epitaxial nanostructures are added to the reaction mixture separately prepared small-size emulsion composition
AgBr0,98I0,02-AgBr0,90I0,10with a speed of 17 ml/min and the pBr value=2,5.
SUBSTANCE: invention relates to nanotechnology and nanostructures, particularly carbon-base materials and can be used in different field of engineering and energetics. In vacuum on substrate made of dielectric material it is sediment evaporated in vacuum silver by means of plasma carbon-base material. Silver sedimentation is implemented before the sedimentation of carbon-base material. Evaporation of carbon-base material, in the capacity of which it is used graphite, is implemented by pulsed arc discharge. Plasma for sedimentation of carbon-base material is created outside the discharge gap area of voltaic arc in the form of compensated currentless for-coagulates of carbonaceous plasma with density 5-1012-1·1013 cm-3, duration 200-600 mcs, recurrence rate 1-5 Hz. During the sedimentation process of carbon-base material it is implemented stimulating effect of carbonaceous plasma by inert gas in the form of ion flow with energy 150-2000 eV, which is directed perpendicularly to carbonaceous plasma stream. Then substrate with sediment on it silver and carbon-base material is extracted from vacuum chamber and annealed on air at temperature 400°C during 10 minutes.
EFFECT: it is manufactured carbon-base material, containing metal, with new properties, for instance electrical conductance and transparency.