JPS5891103A - Production of dispersion of colloidal silver particles - Google Patents

Abstract

PURPOSE:To obtain a dispersion of colloidal silver particles used for yellow filter layers having large absorption of blue light and small absorption of green light by mixing an aq. soln. contg. a reducing agent and an aq. silver salt soln. under stirring that accompanies shear rates higher than prescribed values. CONSTITUTION:Protective colloid such as gelatin is added to an aq. soln. contg. a reducing agent such as dextrin and an aq. soln. of silver nitrate or the like and these are mixed under stirring that accompanies shear rates higher than 1.0X10<4> (sec-1), whereby a dispersion of colloidal silver particles is obtained. The temp. of the soln. in this case is preferably 20-90 deg.C, more particularly 40-80 deg.C, and the time for mixing is preferably within 30min. A stirrer provided with casing is more desirable for the stirrer. The shear rate of this device is expressed by the formula.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a colloidal silver particle dispersion for use in photographic materials. More specifically, the present invention relates to a method for producing a colloidal silver particle dispersion used for a yellow filter layer and a halide prevention layer for color photographic materials.

It is desirable that a single-layer yellow filter used in color photographic materials efficiently absorb blue light and transmit green and red light.However, in known methods, increasing the absorption of blue light increases the Accompanied by absorption, it affects the spectral sensitivity of the green-sensitive layer, making it difficult to improve the color reproducibility of color photographs. Therefore, there is a need for a yellow filter layer that absorbs a large amount of blue light and a small amount of green light.

Yellow filter calendar chain dispersions have traditionally been made primarily by reducing silver salts with phenol IIKs such as hydroquinone or pyrogallol, or alternatively with tannins. Also known are methods using boron foliate, aluminum boron hydride, 7-noborane or hydrazine as reducing agents, and methods using ascorbic acid compounds. However, no matter which known methods are used, sufficient performance cannot be obtained with ordinary propeller stirring.

An object of the present invention is to provide a method for producing a colloidal silver particle dispersion for use in a yellow filter layer, which has a large absorption of blue light and a small absorption of green light.

Another object of the present invention is to provide a method for producing a colloidal silver particle dispersion for use in a Halley sheen prevention layer with high coverage.

The above objects of the present invention are as follows: 1. An aqueous solution containing a reducing agent and an aqueous silver salt solution. (Achieved by mixing under stirring with a shear rate greater than 1'XIO'(5ec-').

The stirring device used in the present invention has a shear rate of 1.0×1 when mixing an aqueous solution containing a reducing agent and an aqueous silver salt solution.
Any type of device may be used as long as it has a shearing force of 0 (&-') or more, but preferably a stirring device provided with a casing is used. An example of this device is patent application No. 55-16819.
No. 3 and Japanese Patent Application No. 168194/1983.

The shear rate of these devices is expressed by equation (1).

τ=πdN/# (1) Shear rate & Gj better, 1.0XlO' (Sec
-') and above.

The reducing agent used in the present invention may be any reducing agent known for producing colloidal tin dispersions, such as:
Phenols such as hydroquinone, pyrogallol, pyrocatechin, para-phenylenediamine, 1,4-dihydronaphthalene, 1-7enyl-3-pyrazolidone, 1-(
Examples include 5-membered ring compounds such as p-7 minophenol-3-7 minnow-2-pyrazolidone. Examples of these reducing agents can be found in “The Theory of the
Process" 3rd edition, C-E@ by Mies, T. H. James, pp. 278-306.

Also, reducing sugars such as dextrin and glucose may be used,
In addition to the above-mentioned organic compounds, reducing agents that can be effectively used in the present invention include compounds such as gill iron, human μ sodium sulfite, hydroxyl 7mine, hydrazine, and polyvalent ionic metals such as titanium, vanadium, and tin. There are inorganic compounds such as salts.

The amount of the reducing agent used in the present invention is preferably at least the same molar amount as the silver salt.

The silver salt used in the present invention may be a water-soluble silver salt such as silver nitrate-silver ammonium complex salt, or silver salt such as silver chloride, silver bromide, silver iodide, silver chloride, silver halide, etc. It may also be a fine particle dispersion.

In the production method of the present invention, Hoto colloid may or may not be present during mixing, and Kffl1m colloid may be added before washing the dispersion. Examples of colloids include starch or starch decomposition products such as dextran or G-dextrin, natural polymers such as protein, especially gelatin, or synthetic polymers such as polyvinyl alcohol and polyvinylpyrrolidone. is used.

In the production method of the present invention, the solution temperature when producing the colloidal silver particle dispersion is preferably 20"C or more and 90"C or less, and more preferably 40C or more and 90"C or less. The time for mixing the aqueous solution containing the reducing agent and the aqueous silver salt solution is preferably within 10 minutes, even more preferably within 10 minutes. After the aqueous solutions on both sides are mixed, stirring may be performed by any known method, or the method of the present invention may be used. Further, the stirring time after the aqueous solutions on both sides are mixed is not particularly limited, but is preferably within ω minutes.

Examples will be given below, but the technical scope of the present invention is not limited in any way by the following examples, and various embodiments are possible.

More? a"i <Example> Solutions I to Solution ■ were prepared according to the following formulations. Solution I Solution ■ Solution ■ Next, the solution [heated to -60"C and various methods and shear rates shown in Table 1! Solution 1'4I was added over 5 minutes while stirring. After completing the addition of solution (■), turn the stirring device on to
After stirring for 15 minutes while keeping the liquid temperature at ω℃, add solution ① to neutralize the solution. Add 800 N of gelatin 1 to the neutralized solution and continue stirring for another 20 minutes. The added gelatin was dissolved. The liquid was then cooled, solidified, shaped into noodles, and washed. This noodle was heated to 40'C to melt it and applied to a cellulose triacetate support to prepare a sample.

Next, the visible absorption spectrum of the sample was measured using a Hitachi self-recording spectrophotometer model EP8323. The results for samples 7 and 8 are shown in Figure 8. Table 1 shows that T500 for the highest concentration.
The ratio of concentrations in nm (Deoo/Dλwax) is shown.

As is clear from Table 1, according to the method of the present invention, absorption of green light (near 500 nm) is significantly reduced.

It's torture p Table-1

[Brief explanation of the drawing]

Figure 81 is a schematic vertical sectional view showing the device used in the present invention;
FIG. 2 is an enlarged vertical cross-sectional view of the mixing i portion in the same figure as above, and FIG. 3 is a schematic vertical cross-sectional view showing another example of the device used in the present invention.
FIG. 4 is an enlarged longitudinal cross-sectional view of the mixer I# portion in the same figure, FIG. 5 is a plan view of FIG. 4, and FIG. 6 is a mixer portion showing another example of the device used in the present invention. FIG. 7 is an enlarged longitudinal sectional view, FIG. 7 is a plan view of the same figure, and FIG. 8 is a graph showing visible absorption spectrum. In the figure, 1 is a reaction container, 2 is a mixer, 21 is a lower open end,
a is the upper open end, 3.3' is the reaction liquid supply pipe, 4 is the lower stirring blade, 5 is the upper stirring blade, 4'4'! The stirring blade, 6 is the rotating shaft, and 7 is the liquid flow regulating plate.

Claims (1)

[Claims] 1. An aqueous solution containing a reducing agent and an aqueous silver salt solution. OXIO'(
A method of producing a colloidal silver particle dispersion by mixing under stirring with a shear rate of &eC-' or more.