JPS61295234A - Metal oxide-coated flakelike titanium oxide - Google Patents

Abstract

PURPOSE:To obtain the flakelike titanium oxide having a superior stability, sticking property, expansibility, luster and a unique property which can change the kinds of the coated metal oxide by coating the surface of the flakelike titanium oxide with the other metal oxide closely. CONSTITUTION:In the titled flakelike titanium oxide whose surface is coated with a metal oxide, the appropriate shapes of the flakelike titanium oxide used as the base material are different according to the usage, however the average thickness of said flake is usually 0.01-3mu and the average dimension is 1-100mu. In case of being compounded with a dressing material, for example, the desirable average thickness is 0.01-0.1mu and the desirable average dimension is about 5-100mu. Also, when used as a dielectric material, the desirable average thickness is 0.1-5mu and the desirable average dimension is about 1-1,000mu. The metal oxides include the oxides of Mg, Zn, Al, In, Si, Sn, Ti, Zr, Cr, Mo, W, Fe, Co, Ni, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to flaky titanium oxide whose surface is intimately coated with a metal oxide.

The metal oxide-coated flaky titanium oxide of the present invention can be used to coat antistatic materials as conductive flakes, materials for electronic components such as capacitors as high dielectric constant flakes, and colored oxides, depending on the type of metal oxide to be coated. It is a pigment that has a large hiding power and a moderate gloss, and it is coated with a colorless low refractive index oxide to become an extender pigment with a transparent appearance.

(Prior Art) Titanium mica, which is formed by coating mica with titanium oxide, has been known as a metal oxide-coated flaky material. ξ is widely used as a pigment because it has a high light reflectance and exhibits gloss.

The characteristics of the material ξ are obtained by using mica as a base material with a low refractive index and coating it with titanium oxide having a high refractive index to a thickness that satisfies the optical reflection conditions.

In order to improve the crystal form and weather resistance of titanium oxide, it is widely known that the titanium mica is coated with or mixed with alumina, silica, tin oxide, etc. (Japanese Patent Publication No. 58-43
068Jji! Public bulletin).

The manufacturing method for titanium mica involves crushing naturally obtained mica,
The desired particle size is selected by classification, and this is heated while being dispersed in a sulfuric acid acidic titanyl sulfate solution to hydrolyze the titanyl sulfate, and titanium oxide fine particles are precipitated on the mica to obtain a titanium oxide coating layer. The method is common.

The titanium mica produced in this way has excellent chemical stability, is harmless, and exhibits strong luster, so it is widely used as a pearl pigment.

(Problem to be solved by the invention) However, since the base material mica is a natural product, various sorting and refining methods have been developed, but there is a drawback that the quality variation due to natural resources persists to the final product. be.

Further, due to impurities contained between the mica layers, some coloring occurs during the firing process, which is an undesirable problem in terms of color effect.

Furthermore, since mica, the base material, has a low refractive index, coating it with titanium oxide, which has a high refractive index, causes a glare, making it unsuitable for use in extender pigment formulations. When it is made to have a refractive index, it is virtually the same as mica flakes, has inferior hiding power, and has disadvantages such as discoloration when wet with water or oil.

In addition, the mica titanium of ξ has a mica thickness of 0.1 to 0.3μ.
) The titanium oxide coating layer is extremely thin compared to (0.05
~0.1 μ), the excellent electrical properties of titanium oxide (high dielectric constant, conductivity upon reduction) are not as apparent.

Further, when the coating metal oxide is, for example, tin oxide, there are problems such as difficulty in surface coating because the crystal shape is too different from that of the base mica.

The present inventors have discovered that flaky titanium oxide tightly coated with a metal oxide has much better stability, adhesion, spreadability, gloss, etc. than conventional pigments derived from mica titanium, and that the coated metal It was discovered that by changing the type of oxide, a flaky material with unique properties could be obtained, leading to the present invention.

(Means for Solving the Problems) That is, the present invention is a flaky titanium oxide whose surface is tightly coated with a metal oxide.

The present invention will be explained in detail below.

Since flakes generally have a distribution, the size is the average size,
In other words, it is defined as the average value of (longest across diameter + shortest across diameter of the flake)/2 for 100 flakes, and the thickness is also defined as the average thickness, that is, the average value for 100 flakes. do.

First, the flaky titanium oxide (hereinafter simply referred to as base material titanium oxide) used as a base material usually has an average thickness of 0.01 to 3μ and an average size of 1 to 100μ, although the appropriate shape varies depending on the application. .

For example, when blending into cosmetics, if high gloss is required, the average thickness is 0.01 to 0.1 μm, and the average size is 5 to 5 μm.
About 100μ is preferable.

This thickness range satisfies the optical conditions for a pearl pigment, resulting in a highly glossy base material with high reflectance.

If the thickness is less than 0.01μ, the mechanical strength will be low and it will not be practical. Moreover, if the thickness is greater than 0.1 μm, the optical reflectance will decrease and high gloss will not be achieved.

When low gloss is required, an average thickness of 0.2 to 2 μm and an average size of 1 to 30 μm are preferred. Thickness is 0.2μ
If it is thinner, the reflectance will be high, and if it is thicker than 2 μm, it will not feel good when it comes in contact with the skin.

When used as a dielectric, the average thickness is 0.1 to 5μ
, the average size is preferably about 1 to 1000μ. If the average thickness is less than 0.1μ, the mechanical strength is poor and handling is difficult. Further, if the thickness is more than 5 μm, the advantages of having a flaky shape, such as improved orientation, are lost. If the average size is smaller than 1μ, it is difficult to maintain the shape of a flake, and if it is larger than 1000μ, the dispersion becomes non-uniform and the electrical properties are poor.

When used as a conductor, the thickness does not contribute to conductivity, so it is preferably as thin as possible, and the average thickness is preferably 0.1 to 1 μm. The average size is preferably larger in order to increase the contact area; the average size is preferably 10 to 1000μ.

- If the average size is smaller than 1 μm, the pigment becomes a pure white pigment, loses appropriate gloss, has good adhesion but has no spreadability, and lacks transparency.

The larger the average size, the better the spreadability, but if the average size exceeds 100 IA, the particles tend to separate and the purpose of uniformly covering the skin cannot be achieved. For this reason, the average size is preferably 100μ or less,
More preferably, it is 70μ or less.

Therefore, the average thickness is 0.01~2μ, the average size is 1
~100μ flaky titanium oxide is preferred.

The base material titanium oxide used in this invention can be produced by various methods.

For example, a method in which an organic solvent solution of titanium alkoxide is applied to a smooth surface and the resulting film is cracked by the action of water vapor to obtain flakes (US Pat. No. 2,941,895); a method in which a titanium tetrachloride solution is applied to a gelatin film and then the gelatin film is formed; method of dissolving titanium-sun potassium fibers (Japanese Patent Application Publication No. 1988-881218) A flaky titanium oxide having a desired thickness can be obtained by the following steps.

As a method for preparing the base material titanium oxide of a specific size, the flaky titanium oxide obtained by the above method is pulverized by a dry ball mill, wet ball mill, vibration mill, roll mill, jet mill, etc. and/or by one gyro mill. vibrating screens, such as sifters and hammer screens;
Wet classification methods such as spiral classifiers or hydraulic classifiers, dry classification methods such as dynamic or centrifugal wind classifiers, or combinations of one or more classification processes such as flotation methods, etc. (Powder Engineering Handbook, edited by Kou Iitani, published by Chokoku Shoten).

The surface of such flaky titanium oxide is tightly coated with a metal oxide.

As the metal oxide, various metals can be selected depending on the purpose.

Specific examples include oxides of magnesium, zinc, aluminum, indium, silicon, tin, zirconium, chromium, molybdenum, tungsten, titanium, iron, cobalt, nickel, and the like.

Depending on the selection of these oxides, flaky materials with various properties can be obtained.

For example, if you want to color it, use colored metal oxides.

That is, when coated with iron oxide, it becomes coppery red, when coated with chromium oxide, it becomes green, and when coated with molybdenum oxide, it becomes blue.

At this time, when a thin flaky titanium oxide is used as a base material, it exhibits a vivid luster, and when a thick flaky titanium oxide is used as a base material, a moist, slight luster is exhibited.

Additionally, if a colorless oxide with a refractive index lower than titanium oxide, such as alumina or silica, is coated to an optically appropriate thickness, light reflection will be almost eliminated, and a transparent and stretchable material can be obtained. .

When coated with indium oxide, tin oxide, etc., it exhibits conductivity.

When coated with magnesium oxide or barium oxide, it exhibits a large dielectric constant.

The form of the metal oxide to be coated may be a uniform film or an aggregate of fine particles, but in the case of fine particles, it is preferable from the viewpoint of uniformity that the diameter is 0.1 μm or less.

The method of tightly coating the base material titanium oxide with a metal oxide is to make the base material titanium oxide into an aqueous slurry, dissolve a soluble metal salt therein, and then add acid, alkali, etc. to the precipitation method. A method in which fine metal hydroxide is precipitated on a titanium oxide base material by hydrolysis by heating, etc., and then fired after coating (
(U.S. Pat. No. 3,087,828), a method in which a metal alkoxide to be coated is dissolved in an organic solvent, mixed with the base titanium oxide, and then the solvent is evaporated to form a coating of the metal alkoxide or its hydrolyzate ( Tokuko Sho 35-5
No. 367), a method of depositing a metal oxide from a gas phase on a titanium oxide substrate, such as by vapor deposition, sputtering, CVD, etc. (e.g., JP-A No. 57-53570, JP-B No. 39-2
No. 5280), a method in which a metal film is first formed on a titanium oxide base material by plating, vapor deposition, sputtering, etc., and then a metal oxide film is formed by oxidizing this metal with heat or the like.

The metal oxide-coated flaky titanium oxide thus obtained is
When incorporated into cosmetics, it exhibits a moderate gloss comparable to that of talc and sericite, spreadability comparable to that of talc, mica, and sericite, and has superior adhesion than talc, mica, and sericite; Calcium carbonate has better spreadability than conventional powdered titanium oxide. Furthermore, it is possible to obtain an excellent cosmetic that is chemically stable, does not undergo deterioration, has a high refractive index, and does not change color even when wet with water.

Cosmetics containing such metal oxide-coated flaky titanium oxide satisfy adhesion, spreadability, and appropriate gloss at the same time, giving an unprecedented smooth and moist feel, and giving a natural beautiful finish with an appropriate slight gloss. . The blending ratio of metal oxide-coated flaky titanium oxide in finishing cosmetics is as follows:
The blending ratio is the same as that of conventional pearl pigments and extender pigments. It depends on the purpose of use, i.e. pearl pigment or extender pigment. It also varies depending on the type of cosmetic.

Of course, conventional extender pigments and pearl pigments may be used in combination, and flaky titanium oxide coated with various metal oxides may also be used in combination.

When used as a pearl pigment, it is used in nail enamel, lipstick, eye shadow, etc.

When used as an extender pigment, it is used in oil-based foundations, pressed powders, pressed door foundations, etc.

Furthermore, the substrate titanium oxide coated with magnesium oxide has a high dielectric constant due to its thin flake shape, is easy to orient during capacitor manufacturing, is easy to densify, and has low temperature dependence, making it suitable for capacitors, etc. Useful as a material.

Furthermore, titanium oxide base materials coated with indium oxide, tin oxide, etc. have higher conductivity than granular materials, and are useful as pigments for antistatic paints, electromagnetic shielding paints, and the like.

As a method for blending the metal oxide-coated flaky titanium oxide, known mixing methods such as a Henschel mixer, a ribbon mixer, a type blender, a kneader with 13 rolls, an extruder, etc. can be used.

(Example) Hereinafter, the present invention will be explained in more detail using Examples.

Note that the light reflectance value (the thicker the thickness, the more metallic luster) is close to each other. ) was measured by the following method.

Measurement of reflectance 100 parts by weight of pigment material was blended with nitrocellulose lacquer to obtain the following test solution.

Pigment substance 10 parts by weight Nitrocellulose R51/4 16 parts by weight Isopropyl alcohol 7 parts by weight Isoamyl acetate 39 parts by weight n-butyl acetate
33 parts by weight diethylene glycol monobutyl ether 3 parts by weight These were sufficiently dispersed and mixed and then fixed on a surface plate. A film was formed by spreading it out to a thickness of 75 μm using a doctor blade on black and white hiding power chart paper and solidifying it.

The film on the black part of this chart paper is JIS-Z
According to the specular gloss measurement method of 5i41, the incident angle is 20 degrees,
The surface glossiness was measured at a reflection angle of 20 degrees.

This surface glossiness was defined as the reflectance.

(Conventional extender pigments such as sericite and talc have 5 to 3
There are various grades of pearl pigments, with the lowest being 40% and the highest being 60%. ) The reflectance of the metal oxide-coated flaky titanium oxide of the present invention is shown in Table 1, and the reflectance of conventional pigment materials is shown in Table 2. (The size and thickness of the particles were measured using a scanning electron microscope.) Reference example (Production of base material titanium oxide) Propionic acid was added to a 40% by weight butanol solution of titanium tetrabutoxide against the titanium in the solution. After adding the mole, the mixture was reacted at 70° C. for 2 hours to prepare a coating solution.

A slide glass, which had been washed with a surfactant, washed with water and dried, was immersed in this solution and pulled up at a speed of 750 m/min.

This was dried in an air bath at 90°C for 30 minutes, and the degree of exfoliation was measured. Next, the thin piece was scraped off onto a glass slide using a scrubber, and the thin piece was baked at 900° C. for 30 minutes. The size of the obtained flakes was 40μ and the thickness was 0.5μ. Further, the degree of flaking was 100%. Furthermore, what is the degree of flaking?
The ratio of the area of the saliva film initially deposited on the slide glass to the area of the flaky film after drying is expressed as x.

Example 1, Comparative Example 1 6 parts of flaky titanium oxide having an average size of 20μ and an average thickness of 0.6μ were suspended in 200 parts of water and then heated to 80°C.

While adjusting the pH to 3 with an aqueous NaOH solution,
A solution prepared by dissolving 201.7 parts of 13.6H in 35 parts of water was gradually poured into the flask.

After the reaction was completed, the mixture was stirred for an additional hour, and the resulting pigment was fired at 850° C. for 30 minutes.

This yielded fine alumina-coated flaky titanium oxide with an AI of 203 min and 5 wL%. The average particle size of alumina was 0.08μ. The reflectance of this pigment is 6.5
It was Chi.

Using this pigment, a powder foundation bag having the composition shown in Table 3 was prepared.

For comparison, a sample containing mica titanium (MP1005) instead of the flaky titanium oxide coated with fine alumina was also prepared.

A sensory test was conducted by 20 women regarding elongation, adhesion, smoothness, gloss, and color feel, and the average score of the results was evaluated using a 5-point scale with the highest score being 5 points.

The results are shown in Table 3.

From this, it can be seen that the powder foundation powder containing flaky titanium oxide coated with fine alumina is superior to the powder foundation powder containing talc in terms of adhesion and smoothness.

Table 3 Powder foundation soap Example 2,
Comparative Example 2 20 parts of flaky titanium oxide having an average size of 6 μm and an average thickness of 0.2 μm, 8 parts of zinc sulfate, 36 parts of urea, and 200 parts of water are uniformly mixed to form a suspension. Next, the temperature of this suspension is raised while stirring and maintained at 90° C. for 2 hours to decompose urea and neutralize the liquid, thereby precipitating fine particles of zinc hydroxide on the flaky titanium oxide. This was then washed with water to remove acid roots and salts, and then fired at 550°C to obtain flaky titanium oxide coated with fine particles of zinc oxide.

The weight ratio of zinc oxide and titanium oxide was 2:10. Using this coated flaky titanium oxide, an oil-based foundation was prepared.

For comparison, a sample using powdered titanium oxide instead of the coated titanium oxide was also prepared.

The results are shown in Table 4.

Table 4 Oil-Based Foundation Practice Example 3, Comparative Example 3 After mixing 5 parts of flaky titanium oxide with an average size of 8μ and an average thickness of 0.5μ, 1.7 parts of tetraethylorthosilicate and 100 parts of ethanol, It was dried at 70° C. in a steam atmosphere to obtain polysiloxane-coated flaky titanium oxide. This was fired at 500°C to obtain flaky titanium oxide coated with silicon dioxide. The weight ratio of SiO and TiOa was 1:10. Electron microscopy revealed that the silica was not in the form of fine particles, but in the form of a uniform film covering the silicon dioxide. Using this coated flaky titanium oxide, pressed powder having the composition shown in Table 5 was prepared.

For comparison, pressed powder using talc was also prepared.

The results are shown in Table 5.

The product using this flaky titanium oxide had excellent elongation and adhesion, and exhibited appropriate gloss.

Table 5 Pressed Powder Example 4, Comparative Example 4 2 parts of flaky titanium oxide with an average size of 8μ and an average thickness of 0.5μ, FeC1! s O-2 parts and 200 parts of water were mixed, and further hydrochloric acid was added to adjust the pH to 1.

0.15 part of urea was added to this and heated. 1 in about 2 hours
The temperature was kept at 00°C for 1 hour, and then it was sent from house to house.

The flakes separated from each other were fired at 450° C. for 1 hour to obtain iron oxide-coated flaky titanium oxide.

Iron oxide coats titanium oxide with uniform fine particles (particle size 0.01μ). An oil-based foundation seal was prepared using this coated flaky titanium oxide.

For comparison, we also prepared a sample using conventional powdered titanium oxide and red iron oxide instead of the coated flaky titanium oxide.

The results are shown in Table 6.

Table 6: Oil-based foundation experiment Example 5, Comparative Example 5 Zinc oxide was vacuum deposited at a rate of 0.5 part on the surface of 10 parts of flaky titanium oxide with an average size of 20 μm and an average thickness of 0.1 μm. did. As a result, flaky titanium oxide coated with zinc oxide was obtained. The particles of coated zinc oxide were 0.01 μm or less.

This zinc oxide coated flaky titanium oxide and for comparison,
A powder eye shadow containing mica titanium (MP 1oof5) was prepared.

The results are shown in Table 6.

Products using zinc oxide-coated flaky titanium oxide have the same elongation as those containing conventional mica titanium, but
It can be seen that it has excellent color feel.

Table 7 Powder Eye Shadow Example 6 210 parts of flaky oxide chips with an average size of 6 μm and an average thickness of 0.2 μm were vapor-deposited with 6 parts of magnesium metal on the surface, and then baked at about 900°C. At this time, magnesium turned into magnesium oxide. The particle size of surface particles is 0.02μ
Met. The dielectric constant of flaky titanium oxide coated with magnesium oxide is 16 (IMH,), and the temperature coefficient is 95X10-'/
'C1q value (according to EIAJ standard) was 5000 or more. Using this flaky titanium oxide coated with magnesium oxide, six dielectric layers with a thickness of 20μ were formed, and electrodes were formed with P d
- A multilayer capacitor of 0.5 vm x O, 8 rm was made using an Ag alloy. The capacity of this capacitor is IQ
QPF and janI were 10-3 or less at 1QQRHz, and the withstand voltage was 50V.

A capacitor made in the same manner using conventional BaTiO3 powder with an average particle size of 1.5μ had a withstand voltage of 32μ.

The one according to this example had a voltage resistance that was about 1.5 times higher than this.

Note that the electrical characteristics were measured using a Yokogawa Hewlett-Packard LF impedance analyzer (Model 4192A).

Example 7 Titanium oxide with an average thickness of 1 μm and an average size of 30 μm was placed in 120 μm of water. Suspend F. This slurry liquid has a pH of
Adjust to 1,0 with dilute hydrochloric acid, 5nCr, 18F,
5bCe2IO, 231! 10 of caustic soda after adding
% aqueous solution was gradually added dropwise while heating to 90°C. As a result, the weight ratio of Snow/Ti02-1
: Second tin oxide coated flaky titanium oxide of No. 1 was obtained.

When this conductivity was measured, it was 60α. When 5% of this was mixed with polystyrene and formed into a sheet using three rolls, a beautiful silvery white sheet with a slight bluish tinge was created.
The electrical resistivity of the sheet was 7 x 106 ohms. The electrical resistance was measured using a high resistance measuring device (Model 4329 A) manufactured by Yokogawa Hewlett-Packard.

Claims (3)

[Claims] (1) Flaky titanium oxide whose surface is closely coated with metal oxide. (2) The metal oxide-coated flaky titanium oxide according to claim 1, wherein the metal oxide consists of fine particles with a diameter of 0.1 μm or less. (3) Mg, Zn, Al, In, Si as metal oxides
, Sn, Ti, Zr, Cr, Mo, W, Fe, Co, and Ni. metal oxide coated flaky titanium oxide.