JPS5933364A - Preparation of mica-base pearlescent pigment - Google Patents

Abstract

PURPOSE:To obtain a good mica-base pearlescent pigment easily, by mixing flake mica particles, titanium tetrachloride, and polybasic org. acids or hydroxypolybasic org. acids with heating. CONSTITUTION:Flake mica particles, titanium tetrachloride, and polybasic org. acids or hydroxypolybasic org. acids are mixed by heating in an aqueous medium to deposit on the surface of mica particles a bydrous titanium salt of org. acid in thin films, or the obtained particles are burnt to dehydrate, thermally decompose, and oxidize said titanium salt. Polybasic org. acids or hydroxypolybasic org. acids to be used are those which form titanium salts of org. acids by reacting with titanates in an aq. soln., and they include oxalic acid, malic acid tartaric acid, citric acid, and their derivatives. Variations in conditions of burning mica through hydrous titanium salt of org. acid pigments permit selective preparation of either anatase or rutile titanium oxide.

Description

[Detailed Description of the Invention] A method for producing a mica-based pearl pigment obtained by depositing a thin film of hydrous titanium oxide on the surface of mica particles in an aqueous suspension of scaly mica particles is described as a known conventional method. Heated hydrolysis method of mica-titanium sulfate suspension (USP 3087827.
3087828). Recently, a method has been developed in which a suspension of mica and titanium tetrachloride is heated under a constant pH [1], and then neutralized with an alkali and hydrolyzed (Japanese Patent Publication No. 49-38
No. 24) is introduced. However, in the former method, due to the aggregation effect of sulfate ions, the resulting hydrous titanium sulfate is not well deposited on the mica surface. In the latter method, it is necessary to continuously add and neutralize an alkaline solution while heating the mica-titanium tetrachloride suspension at a constant pH value of around 2, and the pH value of the solution during hydrolysis is kept small. Even if it becomes a dog, the deposition of hydrous titanium oxide on the mica particle surface is insufficient, and the solution becomes cloudy due to free titanium oxide.

The inventor has conducted extensive research in order to improve the drawbacks mentioned above.
[As a result, we have finally invented an organic acid titanium method that replaces the titanium sulfate method and titanium tetrachloride method described above. heating and mixing an organic acid in an aqueous medium7;
A thin film of hydrous organic acid titanium is applied to the surface of mica fine particles (7
This is a method for producing mica-based pearl pigments, which is characterized by precipitating the pigment or firing it. The details of the present invention will be described below.

[2. The main ones are hasoxalic acid, malonic acid, succinic acid, glutamic acid, tartaric acid, adipic acid, malic acid, aspartic acid, oxalic acid, fumaric acid, citric acid, aconitic acid, Ethylenediaminetetracarboxylic acid, etc. and rust conductors thereof.

The method of using these organic acids is to add them to a mica suspension at a constant temperature.
Hydrolyze a mixed solution of titanium tetrachloride and an organic acid while adding it at a constant rate, or hydrolyze a mixed solution of mica, titanium tetrachloride, and an organic acid while gradually increasing the temperature to make the surface of mica particles contain water. Organic acid titanium may also be deposited.

The amount of organic acid used is determined by the amount of dissolved titanium in the solution (Tie
2 conversion) ratio is preferably 0.4 to 2.5 times, and if it is less than 0.4, the hydrous organic acid titanium produced by hydrolysis will not be effectively deposited on the mica particle surface and will be liberated in the solution and become cloudy.
It is not possible to deposit a desirable film of mica to hydrous organic acid titanium on the surface of mica particles. Moreover, if it is 2.5 times or more, the hydrolysis rate of the titanium salt in the solution becomes small and a long time is required.

Hydrolysis of a suspension consisting of mica-titanium tetrachloride-organic acid 1. In order to effectively deposit the hydrous organic acid titanium produced on the surface of mica particles, mica particles JO~30
Parts by weight Titanium tetrachloride 10-50 Organic acid 4-25 Deionized water 10 (10) In the method of adding a mixed solution of titanium tetrachloride and organic acid to the mica suspension, the following It is preferable to carry out under the following conditions.

Solution addition rate 8~] (me/min, )
Solution addition time 1 to 8 (hs) Temperature of hydrolysis system 100 to 7 (1 ('C) (2) In the method of raising the temperature of a suspended solution of mica - titanium tetrachloride - organic acid, the temperature reaches 100 °C Sales within 1 to 10 hours (hs) are preferred.

The generation mechanism of the hydrous organic acid titanium of the present invention is complex, and the generation mechanism of hydrous titanium sulfate and hydrous titanium oxide produced by the conventional titanium sulfate method and titanium chloride method, respectively, is complicated and is not uniform at present. Although it is still complicated as has not been discussed, and the present inventor cannot clearly discuss it, when looking at these hydrous organic acid titanium by DTA analysis, as shown in Figure 1, the usage l
Also, depending on the type of organic acid, the temperature range of the exothermic curve may be 200°C.
Before and after (in the case of hydrous titanium tartrate (2)) and 300℃
It is shown that the before and after results (in the case of hydrous titanium citrate (1)) are different, and it is confirmed that hydrous organic acid titanium is deposited on the mica surface.

The deposition state of the hydrous organic acid titanium produced by the hydrolyzed VC of the present invention on the mica particle surface is different from that of the conventional titanium sulfate method and titanium tetrachloride method as described below.

Thickness of hydrous titanium film deposited on mica particle surface (d)
and this thickness (optical interference theory due to increase in dl) (optics, Kozo Ishiguro, Kyoritsu Zensho volume 56, P-170, Showa 137 9
) and this specific example (USP-3087827)
The color changes based on this are gray (also called silver color), yellow, red, violet, blue, and green, but this also depends on the refractive index (ND) of the film and the wavelength (α) of the light that passes through this film.
Related to i).

ND-d=k・(!,...(1) Also, the refractive index (ND) of the coating layer in this relationship is the density of the coating itself (
It is also related to p). In other words, the density (p
), thickness (d3) are also different, and therefore the refractive index (ND) of each film is also different.

In other words, titanium sulfate method, titanium tetrachloride method,
Each of the organic acid titanium methods of the present invention has the same hydrolysis rate (T
ie2 conversion), the thickness (mountain, density (/J), and refractive index (ND) of the film of the hydrous titanium sulfate, hydrous titanium oxide, and hydrous organic acid titanium films formed on the mica surface are respectively Since they are different, the interference wavelength (αi) of light also becomes a stationery item.

In particular, the density (ρ) of the hydrous organic acid titanium film deposited on the surface of the mica particles of the present invention is smaller than that of the hydrous inorganic titanium film of the other two methods at the early and middle stages of hydrolysis, and the thickness ( d) becomes a dog, but the final stage of hydrolysis is 100
At °C, there is a rapid increase in film density (e), which causes a return phenomenon of interference color wavelength (αi). This phenomenon is also a feature of the organic acid titanium method of the present invention, as shown in Table 1.

Table 1. ■ Mica surface area of hydrated titanium film in hydrolysis system: 6n? /y, usage amount 24y titanium salt amount T
iO2 equivalent: 107 When mica to hydrous organic acid titanium obtained by the organic acid titanium method of the present invention is fired at a temperature of 200°C or higher in a non-oxidizing atmosphere, the organic components on the mica surface are carbonized and - It becomes a black mica pearl pigment. Therefore, in an oxidizing atmosphere, 2
When fired at a temperature of 00°C or higher, the organic acid titanium film on the mica surface undergoes oxidation easily due to the combustion energy of the organic component, resulting in the effect of transforming into a dense titanium oxide film. Depending on whether this effect is achieved gradually or rapidly with respect to temperature, it is possible to differentiate between anatase type titanium oxide film and rutile type titanium oxide film as described below.

Differentiating the production of anatase-type and rutile-type titanium oxide films based on differences in firing conditions between mica and hydrous organic acid titanium pigments (1) When the temperature in the furnace is gradually raised from room temperature to around 900°C, anatase-type titanium oxide is used. It becomes a mica-based pearl pigment with a film.

(2) When it is placed under a constant temperature of about 500° C. to about 900° C. and then rapidly raised to about 900° C., it becomes a mica-based pearl pigment having a rutile-type titanium oxide film.

Examples will be described below.

Example 1゜Surface area 6 n? /y mica particles 24y are suspended in 500y deionized water and warmed to 90'C.

Titanium tetrachloride 23.89 (Tie2 equivalent 1
When a mixed solution consisting of ioy), ioy tartaric acid, and 500 y of deionized water is continuously added and hydrolyzed at a rate of 2 me/min, a film of hydrous titanium tartrate formed by hydrolysis over time forms on the surface of the mica particles. As it is deposited and hydrolyzed, the hue of the mica suspension changes from silver to red, which is the first interference color. If heating is continued, this red color disappears and the color returns to pale yellow, which is close to the original silver color. This was filtered for 1ri, further washed and filtered with deionized water,
When dried at 0-100°C, hydrous titanium tartrate is deposited on the surface of the mica particles, and powdered mica becomes a hydrous titanium tartrate pigment. Gradually heat this in the oven from room temperature to 9.
By raising the temperature at 00℃ and firing for an additional hour, a silver-colored mica with an anatase-type titanium oxide film is produced.
It becomes a titanium oxide composite pigment.

Example 2 The mica to water-containing titanium tartrate pigment obtained by drying at 50-100°C in Example 1 was placed in a furnace heated to 700'CK tl, and at the same time the temperature was started to increase. When the temperature is increased to 950° C. for 30 minutes and the mixture is fired for 30 minutes, a mica-titanium oxide composite pearl pigment having a rutile-type titanium oxide film with a silver-colored pearlescent luster is obtained.

Example 3 Fine mica particles 24y having a surface area of 6 rn"/11 were suspended in 600 g of deionized water, and 2 tL of titanium tetrachloride was added to the suspension.
A mixed solution of 3.8y, citric acid 13y, and deionized water 400y was added, and the temperature was started to rise while stirring.The temperature was raised to 12 in 30 minutes until the solution temperature reached 50°C, and then to 100y over the next 3 hours. When the temperature is raised to ℃ and hydrolysis is carried out, a film of hydrous titanium citrate is gradually deposited on the surface of the mica particles, and the color changes from silver to red, which is the first interference color.
When hydrolysis is continued for 4 hours, the red color disappears and the color returns to pale yellow, which is close to the original silver color. This was filtered, further washed and filtered with deionized water, and the result was 50-1
When dried at 00°C, hydrous quenched titanium is deposited on the surface of the mica particles.1. It becomes a powdery mica to hydrous titanium citrate pigment. This is gradually heated from room temperature to 900° C. over 3 hours in a furnace, and then fired for another 1 hour to obtain a mica-titanium oxide composite pigment having a silvery pearlescent anatase-type titanium oxide skin reflection.

Example 4 The mica to hydrous titanium citrate pigment obtained by drying at 50-100°C in Example 3 was heated to 800°C [
At the same time, the temperature was raised to 950℃ in 1 hour.
℃ and further firing for 30 minutes at this temperature produces silver-colored mica with a rutile-type titanium oxide film on the surface of the mica particles.
It becomes a titanium oxide composite pearl pigment.

Example 5゜Surface area 3rr? /y of mica fine particles 24y were suspended in 500y of deionized water, heated to 70°C, and at this temperature 23.8y of titanium tetrachloride, 12y of oxalic acid, 1500y of demineralized water were suspended in 500y of deionized water. A mixed solution consisting of
When continuous addition and hydrolysis are carried out at a rate of
As the temperature continues to rise, this green color disappears and the color returns to blue, which is close to the red color of the first interference color. When this is filtered, washed with deionized water, filtered, and dried at 50 to 100°C, hydrous titanium oxalate is deposited on the surface of the mica particles, resulting in powdery mica to hydrous titanium oxalate pigment. The temperature of this L is raised from room temperature to 900° C. over 2 hours in a furnace, and then fired for another 1 hour to form a mica-titanium oxide pigment having a first interference color of red.

Example 6 Mica particles 24F' (r-1) with a surface fft3rn''/y were suspended in 600y of deionized water, and titanium tetrachloride 4
A mixed solution consisting of 7.6y, 20P of malic acid, 400y of ionized water, and stirring was started to raise the temperature. The temperature of the solution was raised to 50°C in 30 minutes [7. Afterwards, the temperature was raised to 100°C over 3 hours to carry out hydrolysis, and a film of hydrous titanium malate was formed on the surface of the calcined titanium malate. Gradually deposits (7. Silver color becomes yellow, red, blue, green as the first interference color, yellow, red as the second interference color.
When heating is continued at 00° C. for 5 hours, the second interference color red disappears and the second interference color returns to yellow, which is close to the first interference color green. This was filtered and further washed and filtered with deionized water [7] The wet cake obtained in step 7 was dried at 50-100°C to form powdered mica with hydrous titanium malate deposited on the surface of the mica particles - hydrous malic acid. The titanium face prick was made by putting it directly into a furnace that had been heated to 800°C and then starting to heat it up.7
When the mixture is fired at 950° C. for 1 hour for 12 minutes and then for 30 minutes, a green rutile yamica-titanium oxide composite pearl pigment with a first interference color is obtained.

[Brief explanation of the drawing]

FIG. 1 is a graph showing DTA analysis of mica fine particles coated with hydrous organic acid titanium according to the present invention, in which (1) t- is coated with hydrous titanium citrate and (2) Fi is coated with hydrous titanium tartrate. show. Applicant Sanyo Shiki Co., Ltd. Agent Toshio Takigawa

Claims (5)

[Claims] (1) Scale-like mica fine particles, titanium tetrachloride, and a polybasic organic acid or oxypolybasic organic acid are heated and mixed in an aqueous medium 5, and hydrous organic titanium acid is deposited as a thin film on the surface of the mica fine particles. A method for producing mica-based pearl pigments. (2) Scale-like mica fine particles, titanium tetrachloride, and a polybasic organic acid, < is an oxypolybasic organic acid, are heated and mixed in an aqueous medium 7, and a thin film of hydrous organic titanium is formed on the surface of the mica fine particles. 7. A method for producing a mica-based pearl pigment comprising titanium oxide-coated mica fine particles, which comprises precipitation, followed by firing the organic acid titanium-coated mica fine particles, followed by dehydration, thermal decomposition and oxidation. (3) The mica-based pearl pigment according to claim 1 or 2, wherein the polybasic organic acid (7〈 is oxypolybasic organic acid is 7-euric acid, malic acid, tartaric acid, or citric acid) manufacturing method. (4) A method for producing a mica-based pearl pigment according to claim 2, in which the organic acid titanium-coated mica fine particles are heated gradually from room temperature to around 900°C. (5) When firing the organic acid titanium-coated mica fine particles,
The method for producing a mica-based pearl pigment according to claim 2, wherein the organic acid titanium-covered mica fine particles are placed in a furnace whose internal temperature is 500° C. or more and 950° C. or less and fired.