JPS63258624A - Manufacture of emulsion - Google Patents

Abstract

PURPOSE:To permit a hydrophobic photographic compound to be dispersed evenly in a hydrophilic binder solution by causing a mixture of an aqueous solution and an oily solution to be ejected from a jet nozzle provided along the center axis of a shearing chamber while rotating the mixture in a spiral manner. CONSTITUTION:An oily solution containing a hydrophobic material and an aqueous solution containing a hydrophilic binder are mixed in advance, and the mixture is pressed into an intake pipe communication to a shearing chamber 2 at a pressure of about 60kg/cm<2> from an intake port 1. After this, the pressurized mixture is ejected in a direction tangential to the wall surface 21 of the shearing chamber 2 through an ejection port 12. Next, the mixture starts its spiral motion by gradient wall surface 22, moving to the center axis of the shearing chamber 2, while accelerating its velocity in the tangential direction in proportion with the reduction of the turning curvature. After this, the mixture is ejected from an outflow port 3 via an outflow cylinder 31 and an outflow pipe 32 after passing through an outflow nozzle 23.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing an oil-in-water emulsion, and more particularly to a method for uniformly dispersing a hydrophobic photographic compound in a hydrophilic buying solution.

[Background of the invention]

Hydrophobic photographic compounds are uniformly and stably dispersed in a hydrophilic binder such as gelatin as a dispersion medium in order to ensure photographic performance and image quality. A representative example of such compounds is a compound that forms a dye by a coupling reaction with an oxidized form of a color developing agent during color development (hereinafter referred to as a dye-forming coupler).

These dye-forming couplers have a group called a ballast group in the molecule, which makes the coupler non-diffusive and has 8 or more carbon atoms, and are hydrophobic.

In addition, the dye-forming coupler has a color correction effect, and by coupling with an oxidized product of a color developing agent, a development inhibitor, a development accelerator, a bleach accelerator, a developer, a silver halide solvent, Includes a variety of couplers that release 7 functionally useful fragments such as toning agents, hardeners, capri agents, antifoggants, chemical sensitizers, spectral sensitizers, and desensitizers. Ru. Among these, couplers that release a development inhibitor during development to improve image sharpness and image graininess are called DIR couplers. Some DIR Kabras generate colorless compounds through a coupling reaction with the oxidized form of the developing agent. All of these are hydrophobic compounds that are essential in the production of photographic materials.

Into a hydrophilic piping solution of a dye-forming coupler, a colored coupler, a DIR coupler, or a hydrophobic compound such as an image stabilizer, a color antifoggant, an ultraviolet absorber, or an optical brightener, which are made hydrophobic as described above. For dispersion, solid dispersion method, latex dispersion method, oil-in-water emulsion dispersion method, water-in-oil emulsion dispersion method are used.
? Various methods can be used. This can be appropriately selected depending on the chemical structure of the hydrophobic compound such as coupler.

The oil-in-water emulsion dispersion method for dispersing hydrophobic compounds such as couplers is usually carried out by dissolving them in a high-boiling organic solvent with a boiling point of 150'C or more in combination with a low-boiling point and/or water-soluble organic solvent as necessary. Then, after emulsifying and dispersing a surfactant in a hydrophilic binder such as an aqueous gelatin solution using a dispersion means such as a homomixer, homogenizer, colloid mill, 70-note mixer, or sonic device, the desired A step of removing the low-boiling organic solvent simultaneously with the dispersion or dispersion added to the hydrophilic colloid liquid may be included. Examples of high-boiling point solvents include phenol derivatives that do not react with the oxidized form of the developing agent, 7-tar acid alkyl esters, phosphoric esters, citric esters, benzoic esters, alkyl 7-mides, fatty acid esters, trimesic esters, etc.
An organic solvent having a temperature of 50° C. or higher is used.

Low boiling or water-soluble organic solvents can be used in conjunction with or in place of high boiling solvents. Examples of organic solvents having a low boiling point and substantially insoluble in water include ethyl acetate, propyl acetate, butyl acetate, butanol, chloroform, carbon tetrachloride, nitromethane, nitroethane, and benzene.

In addition, if the dye-forming coupler, DIR coupler, colored coupler, DIR compound, image stabilizer, color discoloration inhibitor, ultraviolet absorber, optical brightener, etc. have an acid group such as carboxylic acid or sulfonic acid, may be introduced into the hydrophilic colloid as an alkaline aqueous solution.

In the case of photographic light-sensitive materials, for example, dye-forming couplers, the conventional method for producing the oil-in-water emulsion is to use an emulsifying dispersion machine such as the above-mentioned homomixer, homogenizer, colloid mill, 70-noe totomixer, ultrasonic device, etc. A method has been adopted to use When a colloid mill, a homomixer, a 70-noetomixer, or the like is used as an emulsifying and dispersing machine, a sufficiently finely divided emulsion cannot be obtained, and this is often inappropriate as a method for dispersing hydrophobic photographic compounds. In addition, when using an ultrasonic dispersion machine or a high-pressure homogenizer, although a sufficiently finely divided emulsion can be obtained, a large amount of heat is generated during the dispersion process, and a large amount of energy is required to obtain a large amount of emulsion. Therefore, there were many practical problems.

[Purpose of the invention]

An object of the present invention is to improve these drawbacks and provide a dispersion method for obtaining a highly dispersible emulsion of a hydrophobic photographic compound.

Still another object is to provide a method for producing an oil-in-water emulsion using a dispersing device that has a simple structure, is easy to maintain, does not generate heat that is disadvantageous to stable atomization, and has extremely high emulsification efficiency. be.

[Structure of the invention]

The object of the present invention is to provide a method for producing an oil-in-water emulsion for photography by mixing an aqueous phase solution containing a hydrophilic binder and an oil phase solution containing a hydrophobic substance, An emulsifying gc comprising a shearing chamber, the liquid being spouted in the direction of the shearing chamber, moving the liquid in a spiral direction while rotating in the direction of the shearing chamber, and causing the liquid to flow out from outflow nozzles provided along each axis in the shearing chamber. This is accomplished by a 91 method of emulsion using゛In the present invention, shearing chambers having the above specifications or emulsifying devices including the shearing chambers may be connected in multiple stages for continuous emulsification, or other types of emulsifying and dispersing devices may be installed in front of and/or They may be linked later and used for continuous emulsification.

Embodiments of the present invention will be explained below with reference to the drawings.

FIG. 1 is a sectional view of a shear chamber cell of an emulsification device according to the present invention.

An oil phase solution containing a hydrophobic substance and an aqueous phase solution containing a hydrophilic substance are mixed in advance, and are forced into the inlet pipe 11 leading to the shearing chamber 2 under pressure of about 60 kg/c+s from the inlet 1, and then It is ejected from the outlet 12 in the tangential direction of the wall surface 21 of the shearing chamber 2, causes a spiral movement by the inclined wall surface 22, moves toward the central axis of the shearing chamber while increasing the speed in the tangential direction as the rotational curvature decreases, and the central axis An outflow cavity 3 that communicates with an outflow port 3 from an outflow nozzle 23 provided above and/or below.
1. It is discharged from the outlet 3 via the outlet pipe 32. During this time, in the shear chamber 2: (1) shear forces between adjacent stratified flows rotating at different speeds; (2) shear forces in the radial direction of the rotating circle that act on solution masses or droplets with different densities; Strong emulsification and dispersion can be performed by centrifugal force and (3) crushing force due to cavitation caused by periodic vibrations derived from wave motion.

As a method for ejecting fluid into the shearing chamber, a planter pump, gear pump, Mo7 pump, etc. can be used depending on the purpose. In addition, the shearing chamber has a multi-stage shearing chamber structure in which the outflow port 3 of a unit shearing chamber cell is connected to the inflow port 1 of another cell, and the solution is continuously passed through, thereby further atomizing the dispersed particles and making them homogeneous. It is possible to promote the In the embodiments described above, in order to effectively perform emulsification and dispersion, the speed at which the solution is ejected into the shearing chamber is important, and by controlling this ejection speed, the average particle size of the desired emulsion can be adjusted. It is possible to maintain the level of diameter. The optimum value of the ejection speed varies depending on the type and properties of the liquid to be emulsified and dispersed, but the viscosity of the liquid is an important parameter.

FIG. 2 shows the relationship between the optimum jetting speed and the average particle size, which was determined experimentally. Furthermore, in this embodiment, the diameters of the shear chamber and the jet nozzle are also very important factors in enhancing the dispersion effect. In order to determine the optimum jet diameter, it is possible to measure the pressure loss at the solution inlet and outlet. In this embodiment, the preferred ejection speed is 2 to 500 n/see, and the pressure loss is 10 to 150 Kg, preferably 20 to 100 K.

By the method of the present invention described above, the following effects could be obtained.

1. It has become possible to mar the dye-forming coupler of a photographic compound to the desired average particle size with extremely little energy loss and with small power.

2. Because there is almost no heat generation during the dispersion process, there is no longer any deterioration in quality during the dispersion process, unlike in conventional methods.

3. When using other emulsifying and dispersing machines, by using the emulsifying device of the present invention and performing micronization in advance, the emulsifying efficiency of the entire emulsifying system can be increased, and the heat generated during the dispersing process can be reduced by 1 ounce. It became like that.

4. Since the structure is simple, it is easy to clean and maintain [Examples] In order to further clarify the effects of the present invention, the present invention will be described below with reference to Examples.

Example-1 (Emulsified dispersion of Magenta Kabra) Aqueous phase solution: H20-728, 1 cc Gelatin...38.1° Oil phase solution: Magenta Kabra L low boiling point solvent Ethyl acetate...143.7
The cc aqueous phase solution was stirred and dissolved at 60℃, and the oil phase solution was dissolved at 70℃.
'C, the mixed liquid was used as an emulsified sample liquid, and a homomixer, high-pressure homogenizer, and ultrasonic dispersion machine were used as comparison methods.
Table 1 shows what was dispersed by the dispersion method of the present invention.

Table 1 As shown in Table 1, the dispersion according to the present invention not only had very high emulsification efficiency but also was able to obtain a highly dispersed state.

Implementation rIA-2 (emulsified dispersion of yellow coupler) aqueous phase solution; rH20...710 cc L gelatin...38.8
FI oil phase solution: "Yellow Coupler L low boiling point solvent ethyl acetate...155c
c The aqueous phase solution was stirred and dissolved at 60°C, and the oil phase solution was dissolved and stirred at 70°C. These two solutions were premixed, and the mixed solution was used as an emulsified sample solution, and the emulsifier of the present invention was connected directly in two stages in series and passed through it at a rate of 80 kg/cm2 to obtain a dispersion (1).

Furthermore, the above-mentioned sample was dispersed for 30 minutes using an ultrasonic homogenizer to obtain a dispersion (U). 20m of each of these dispersions
ff1 and 1,2-bisvinylsulfonylethane O,S,
, was added to 15 mN of a blue-sensitive silver iodobromide emulsion prepared in a conventional manner, and coated on a support consisting of a subbed cellulose triacetate film and dried.
Samples corresponding to dispersions (1) and (II) are designated as samples (1) and (n'), respectively.

Each of the samples (1) and (II) was wedge exposed and processed according to the processing steps shown below.

(Processing process) Temperature Time Color development 38℃ 3'15 ~ Bleaching 38℃ 6'30''
Wash with water 38℃ 3' 1
5″ fixation 38℃
6'30'' water wash 38℃
3'15" Stabilization 38°C 1'30" Next, the color images formed on Samples N) and (It) were measured. Example 3 (emulsified dispersion of cyan coupler) aqueous phase solution; (-820-738, 7cc 1 gelatin...36.9
g Oil phase solution; L low boiling point solvent #ethyl acid...131.8
The cc aqueous phase solution was stirred and dissolved at 60℃, and the oil phase solution was dissolved at 70℃.
The mixture was dissolved and stirred. Premix these two solutions,
The mixed solution was once cooled to 40°C and used as an emulsified sample solution using a dispersing machine (including two shear chambers of the present invention) (
40Kg/cm2) and a high pressure homogenizer (500KF
I/am') were combined and continuously dispersed, and the final liquid temperature was 62°C. In addition, the average particle size at this time was 0.12 μm, and the particle size distribution was 0.08 μm to 0.20 μm.
A microscopic homogeneous emulsion was obtained. On the other hand, as a comparative example, three high-pressure homogenizers were connected and the same sample was continuously heated to 500K.
When dispersing at g/am2, the final liquid temperature was 74°C.
When the liquid was observed with an microscope, it was found to contain many air bubbles.

[Brief explanation of the drawing]

FIG. 1 is a cutaway sectional view of a shear chamber cell of an emulsification device according to the present invention. FIG. 2 is a diagram showing the relationship between the ejection speed of the mixed solution into the shear chamber and the average particle size. 2... Shearing chamber 12... Jet outlet 21... Wall surface 23... Outflow nozzle Applicant Konishiroku Photo Industry Co., Ltd. Figure 2 = 1j 7 (-A-) →

Claims (3)

[Claims] (1) In a method for producing an oil-in-water emulsion for photography, an aqueous phase solution containing a hydrophilic binder and an oil phase solution containing a hydrophobic substance are mixed and ejected in the tangential direction of the wall surface of a shearing chamber, Production of an emulsion using an emulsification device including a shearing chamber, characterized in that the liquid is moved in the direction of the shearing chamber while rotating in a spiral pattern, and is discharged from an outflow nozzle provided along the central axis of the shearing chamber. Method. (2) The method for producing an emulsion according to claim 1, in which two or more of the shearing chambers or emulsifying devices each including a shearing chamber are connected to each other and continuously emulsified and dispersed. (3) The method for producing an emulsion according to claim 1 or 2, wherein the emulsification device including the shearing chamber and another emulsification dispersion device are combined to continuously disperse the emulsion.