JPS623003A - Scaly inorganic oxide and production thereof - Google Patents

Abstract

PURPOSE:To produce scaly inorganic oxide having improved transparency and relatively long side in comparison with thickness, by freezing a colloidal solution of an inorganic oxide, precipitating particles of the inorganic oxide between crystal plane of a solvent and removing the solvent. CONSTITUTION:A colloidal solution consisting of one or more organic oxides of TiO2, SiO2, Al2O3, Fe2O3, ZrO2, SnO and Sb2O3 and/or hydrous inorganic oxide is cooled at a temperature to freeze the solution and frozen in a given time. Consequently, colloidal particles in the solution are separated and precipitated on the gaps between the crystal planes of the solvent of the colloidal solution. The frozen material is dried in a vacuum and the solvent is removed while keeping the frozen material at a temperature not to thaw the frozen material. Consequently, the scaly inorganic oxide or hydrous inorganic oxide having 0.05-5mum thickness, >=5 ratio (aspect ratio) of the maximum length of side to thickness and improved transparency is obtained.

Description

[Detailed Description of the Invention] L! Yo five ox ■ minutes! The present invention relates to a novel scale-like inorganic oxide that is transparent and has a substantially constant thickness, and a method for producing the same.

1. Background of the mouth and its 4 topics - Inorganic substances, especially inorganic oxides, are usually in the form of lumps or particles, but some inorganic substances are in the form of scales. Examples of scaly inorganic substances include natural minerals such as mica and sericite, synthetic mica, scaly graphite, glass flakes, and scaly crystals such as calcium phosphate.
It is widely used in electrical parts, building materials, paints, plastic fillers, cosmetics, etc.

Among these, synthetic scaly inorganic substances have been synthesized as follows. For example, synthetic mica is S i 02
It is manufactured by hydrothermally synthesizing a solution prepared by dissolving raw materials such as , Na, , O, MgO, F, etc. in water to a predetermined composition in an autoclave, but in the manufacturing process, water etc. Due to reasons such as swelling and spreading of mica layers, the thickness of the scale-like material obtained was often inconsistent. Glass flakes are manufactured by making molten glass into a thin film and then cooling it to make it into scales. At present, scale-like substances thinner than this are not processed.

Furthermore, scaly crystals such as calcium phosphate are usually produced by precipitating flaky crystals in a solution, but this method has the problem that it is difficult to control the thickness of the scaly crystals produced by 1q. There was a thunderstorm.

By the way, titanium oxide, silicon oxide, aluminum oxide,
Iron-free oxides such as iron oxide, zirconium oxide, tin oxide, and antimony oxide, whether naturally occurring or synthesized by various methods, have a spherical or irregular shape. No scale-like material has been obtained that has a regular shape and the length of the pieces is very long compared to the thickness.

Furthermore, since the above-mentioned inorganic oxides are spherical or amorphous, their visible light transmittance is low, making it difficult to obtain ones with excellent transparency.

By the way, if the above-mentioned inorganic oxides could be formed into scales with excellent transparency and very long pieces compared to their thickness, they could be used as catalysts or their carriers, electrical parts, fillers for building materials, and paints. It is expected to be used as fillers, plastic fillers, and cosmetics.

The present inventors have discovered that inorganic oxides such as titanium oxide, silicon oxide, aluminum oxide, iron oxide, zirconium oxide, tin oxide, and antimony oxide have excellent transparency and are extremely thin compared to their thickness. After researching how to form scales into long scales, it was discovered that by freezing a colloidal solution of the inorganic oxide and removing the solvent, scales could be produced from the oxide, leading to the completion of the present invention. Ta.

Purpose of the Invention The present invention provides 11f made of titanium oxide, silicon oxide, aluminum oxide, iron oxide, zirconium oxide, tin oxide, and antimony oxide, which has excellent transparency and has a very long piece length compared to its thickness. The object of the present invention is to provide a scale-like material made of one or more kinds of inorganic oxides selected from the following, and a method for producing the same.

SUMMARY OF THE INVENTION The present invention uses novel scaly titanium oxide, silicon oxide, aluminum oxide, iron oxide, zirconium oxide, and tin oxide that impair transparency and have extremely long pieces compared to their thickness. , antimony oxide, and one or more inorganic oxides selected from the group consisting of antimony oxide.

In this scale-like inorganic oxide, the thickness is 10 μm or less, preferably 0.05 to 2 μm, and the ratio of the thickness to the longest length of the flakes (aspect ratio 1 to 1) is 5 or more, preferably 1
0 or more, and the transmittance of visible light at 550 nm is 60
% or more, preferably 80% or more.

In addition, according to the present invention, there is a scaly material which is excellent in transparency and whose length is very long compared to its thickness. The method for producing a single oxide or a hydrous inorganic oxide involves freezing a colloidal solution of an inorganic oxide, a hydrous inorganic oxide, or both, and adding inorganic oxide to the gap between the crystal planes of the solvent of the colloid solution. The method is characterized in that after precipitating the material particles, the water-containing inorganic oxide particles, or both, the solvent is removed while maintaining the temperature at a temperature at which the frozen material does not thaw.

The above inorganic oxides include titanium oxide, silicon oxide,
Aluminum oxide, iron oxide, zirconium oxide, tin oxide, antimony oxide, etc. are used.

Detailed description of the invention The present invention will be explained in more detail below.

No Iar! according to the present invention! I-oxides have a scale-like shape with excellent transparency and extremely long pieces compared to their thickness, and include titanium oxide, silicon oxide, aluminum oxide, iron oxide, zirconium oxide, tin oxide, and antimony oxide. It is composed of one or more selected from the group consisting of:

The thickness of this flaky inorganic oxide is desirably 10 μm or less, preferably 0.05 to 2 μm. If the thickness exceeds 10 μm, it is undesirable because the characteristics of a scale-like material cannot be expected;
．． If it is less than 0.05 μm, the mechanical strength of the scale-like material is too weak, which is not preferable. Further, the aspect ratio, which is the ratio between the thickness and the longest length of the piece, is 5 or more, preferably 10 or more. If the aspect ratio is less than 5, it is not preferable because the characteristics of a scale-like material cannot be expected compared to a granular material. Furthermore, the scaly inorganic oxide obtained by the method according to the present invention has excellent transparency and has a 550 nm
It is desirable that the visible light transmittance of m is 60% or more, preferably 80% or more. Note that the visible light transmittance of the scaly inorganic oxide according to the present invention is calculated by adding 90 parts of liquid paraffin to the top of the 10-car scaly inorganic oxide according to the present invention, After dispersing well with industrially manufactured
This dispersion was applied to a transparent quartz plate to a thickness of 5 μm, and the transmittance of visible light having a wavelength of 550 nm was determined using spectroscopy and photometry.

The scaly inorganic oxide according to the present invention may be composed of titanium oxide, silicon oxide, aluminum oxide, iron oxide, zirconium oxide, tin oxide, antimony oxide alone,
It may also be composed of two or more of these inorganic oxides.

Hereinafter, a method for producing a scale-like V3 oxide-free material having excellent transparency and having a very long piece length compared to its thickness will be described according to the present invention.

First, a colloidal solution of one or more inorganic oxides or hydrous inorganic oxides or both at a predetermined concentration is prepared.
These solutions are cooled below the freezing temperature and frozen within a predetermined time. When this colloidal solution is frozen, the colloidal particles in the solution are separated from the solvent and precipitate in the gaps between the crystal planes of the solvent of the frozen colloidal solution. The I-free oxides or hydrous inorganic oxides thus precipitated polymerize or aggregate with each other to form scales. Then,
The desired scale-like product can be obtained by drying the frozen product using an appropriate method to remove the solvent while maintaining the shape of the scale-like product.

In the present invention, the colloidal solutions of inorganic oxides and hydrous inorganic oxides refer to silicic acid solutions, silica colloids, mineral salts, or organic acids obtained by dealkalization of alkali silicates such as water glass, hydrolysis of ethyl silicate, etc. Although this term includes colloidal solutions of oxides such as titanium, tin, zirconium, iron, and antimony obtained by hydrolysis of salts, the colloidal solutions used in the present invention include those obtained by the above method. It is not limited to, and may be manufactured by any method.

The average particle diameter of the colloid particles in such a colloid solution is desirably 250 mμ or less, preferably 80 mμ or less. The smaller the average particle diameter of the colloidal particles, the more densely and firmly the precipitated colloidal particles will polymerize or aggregate, and the obtained scale-like inorganic oxide will have excellent transparency and strength. On the other hand, the average particle diameter is 250m
When μ is exceeded, the colloidal particles precipitated in the gaps between the crystal planes of the solvent during freezing have a large particle size, so the surface energy becomes small, and the bonding force between the precipitated particles becomes weak. Therefore, even if the frozen product is dried to remove the solvent, a scaly inorganic oxide cannot be obtained, but only a powder or a lump can be obtained.

When the concentration of the inorganic oxide or the hydrated inorganic oxide in the colloidal solution is 0.1% by weight or more based on the oxide, the desired scale-like material can be obtained. As the concentration of the oxide increases, and other freezing conditions remain the same, more particles will precipitate in the gaps between the crystal planes of the solvent, resulting in thick scales. However, if the concentration of the oxide becomes too high, it cannot exist stably as a colloidal solution, and even if such a highly concentrated colloidal solution is used, a scale-like inorganic oxide cannot be obtained. Considering the above, the concentration of the colloidal solution that can be used for the purpose of the present invention varies greatly depending on the type of oxide, but for example, in the case of silicon oxide, it is preferably 60% by weight or less, In the case of aluminum oxide, it is preferably 10fflff1% or less, and in the case of titanium oxide, it is preferably 40% by weight or less. Also 0, 1
If it is less than % by weight, it is difficult to obtain a scale-like product, and even if it is obtained, the thickness is extremely thin and it is easy to break and powder when handled, which is not preferable.

Another factor that controls the thickness of the resulting flaky inorganic oxide is the freezing time of the colloidal solution, ie, the time required for a given colloidal solution to completely freeze. The shorter the freezing time, the smaller the single crystal of the solvent becomes, and the fewer colloidal particles are separated from the solvent during crystallization of this crystal, the thinner the scales formed in the interstices of the crystal planes become.

Conversely, if the freezing time is increased, the single crystals of the solvent become larger and more colloidal particles are separated from the solvent during crystallization, resulting in thick scales (for example, when the concentration is 1.0 wt. % silicic acid colloid solution in 7 seconds, 1q of scales with a thickness of about 0.1 μm are produced, whereas when the same colloidal solution is frozen in about 60 minutes, about 2.0 μm in thickness is produced.
A scale of m thickness is obtained.

By the way, if the freezing time is made extremely short, the colloidal solution will eventually reach a so-called instant freezing state, and the colloidal solution will freeze before the solvent and the colloidal particles are separated, making it impossible to obtain scales. Therefore, when freezing a colloidal solution, it is necessary to allow sufficient time for the colloidal particles to separate from the solvent and precipitate while the solvent is frozen and crystallized.

Here, when producing scale-like titanium oxide from a hydrous titanium oxide colloidal solution with a colloidal particle diameter of 30 mμ,
FIG. 1 shows the relationship between the freezing time, the oxide concentration in the colloidal solution, and the thickness of the obtained scale-like titanium oxide. From this Figure 1, when the concentration of titanium oxide is 1.0% by weight, it is sufficient to set the freezing time to 6 seconds to obtain scaly titanium oxide with a thickness of 0.1μ; 2. O,um
It can be seen that approximately 50 minutes of freezing time is required to freeze the scale-like titanium oxide.

Similarly, when producing scaly aluminum oxide from an aluminum oxide colloidal solution with a colloidal particle size of 20 mμ, the relationship between the freezing time, the oxide concentration in the colloidal solution, and the thickness of the obtained scaly aluminum oxide was determined using the following method.
Not shown. Furthermore, when producing scaly silicon oxide from a silicon oxide colloidal solution with a colloidal particle diameter of 12 mμ, Figure 3 shows the relationship between the freezing time, the concentration of oxide in the colloidal solution, and the thickness of the obtained scaly silicon oxide. Shown below.

As described above, the freezing time of the colloidal solution has a large effect on the thickness of the scale-like inorganic oxide to be jqed, and the freezing time of the colloidal solution can be changed mainly by changing the cooling rate of the colloidal solution. Specifically, a container filled with a colloidal solution of a predetermined concentration is set in a freezing device, and the colloidal solution is frozen by setting a cooling rate so that freezing is completed within a predetermined time. Use a container in which the layer of colloidal solution becomes thin, such as a flat container with a shallow bottom. When cooling from both sides, solvent crystals grow upward from the bottom of the container or from the bottom and top of the container toward the center, forming scales with a length comparable to the depth of the liquid. An inorganic oxide of the form is obtained.

At this time, if the cooling temperature is the same, the thinner the liquid layer of the colloidal solution (the liquid depth), the shorter the freezing time. Further, the thicker the material, the longer the freezing time, but if it becomes too thick, problems such as uneven thickness of the resulting scaly material occur, which is not preferable. Therefore, it is desirable that the thickness of the liquid layer of the colloidal solution is 100 mm or less, preferably 5 Q mm or less.

The solvent is then removed from the colloidal solution thus frozen. This solvent removal operation is performed in such a way that the precipitated colloidal particles retain their scaly shape even after the solvent is completely removed. Freeze-drying is a preferred method for this. That is, after the colloidal solution frozen by the method described above is taken out from the freezing device, the solvent is removed by normal vacuum drying while maintaining the temperature at a temperature that does not thaw the frozen material. If the solvent is sufficiently removed by such a method, even if the obtained scale-like material is returned to room temperature, it will not become powder-like and will maintain its scale-like shape.

The scale-like inorganic oxide obtained by this method is
Although it can be used as it is for various purposes, depending on the purpose there are cases where a high degree of strength is required. Oxide is obtained.

Transparent and scaly free lff1 obtained by the method of the present invention
The oxide has a very thin flaky shape with an average thickness, and since it is an inorganic oxide, it has excellent heat resistance, acid resistance, alkali resistance, and solvent resistance. Furthermore, compared to mica or sericite, which are natural scaly minerals, it is extremely pure and homogeneous, so it is used for various purposes.

For example, in the past, when trying to use powders of non-molecular oxides such as silicon oxide, aluminum oxide, and titanium oxide as molded catalysts or carrier materials, it was difficult to mold and mold them using only these inorganic oxides. Therefore, appropriate amounts of natural minerals such as mica or sericite were often added as lubricants. However, the catalyst or carrier obtained as described above has a drawback in that the catalytic activity is reduced by or more than the addition of a lubricant such as mica. However, if the scaly inorganic oxide obtained in the present invention is used as a raw material, a shaped catalyst or carrier can be produced without reducing the catalytic activity.

Furthermore, if the flaky inorganic oxide according to the present invention is used as a plastic additive, the resulting plastic will have improved impact resistance, and since it is flaky, it will have good orientation and improve surface hardness. The effect of improving heat resistance can also be obtained.

Furthermore, by adding a scale-like inorganic oxide consisting of aluminum oxide, silicon oxide, and zirconia oxide to the heat-resistant ceramic molded body, the formability during molding can be improved, and the heat spore resistance and pressure resistance of the resulting heat-resistant ceramic can be improved. Improved.

The flaky titanium oxide or iron oxide according to the present invention has an ultraviolet absorption effect, so when added to a paint, the weather resistance of the paint is improved and it is also effective as a hard coat material. In addition, if a film such as polyethylene film or polypropylene film is mixed with the above-mentioned scaly titanium oxide or iron oxide to make a UV-cut film and used in agricultural greenhouses, it will have a growth-promoting effect on certain types of plants. You can expect it.

In general, the scale-like inorganic oxides of the present invention, such as titanium oxide, iron oxide, silicon oxide, aluminum oxide, and zirconium oxide, have an aspect ratio of 10, the same as mica or sericite, which are conventionally used in cosmetics. ~200
If it is prepared and used in various cosmetics as cosmetics,
Compared to natural mica, it contains extremely few impurities and is homogeneous, making it safer for the skin, and being thinner than natural products, it feels good when used and spreads well.
To obtain a transparent cosmetic composition that hardly removes makeup and does not impair the beauty of bare skin.

Furthermore, the titanium oxide or iron oxide according to the present invention has superior ultraviolet absorption and ultraviolet shielding abilities compared to the particulate titanium oxide conventionally used as an ultraviolet screening agent, and is easy to handle. Moreover, because of its good dispersibility,
Even when used in large quantities in cosmetic base materials, the feeling of use is not impaired.
Furthermore, it is possible to obtain a cosmetic composition that has a transparent effect on the skin and protects the skin from ultraviolet rays.

In addition, the scaly inorganic oxide according to the present invention can be used in various applications such as lubricants, resins, high hardness fillers for improving rubber wear resistance, matte fillers, and non-shrinkage fillers.

RflJI to 4] In the present invention, compared to the oxide which has conventionally been obtained only in the form of particles, it has excellent transparency and uniform thickness, and the length of the pieces is very short compared to the thickness. Large scale-like inorganic oxides are produced. Therefore, this scale-like inorganic oxide can be used as a catalyst or carrier, electrical parts, filler for building materials, etc.
It can be used as paint filler, plastic filler, cosmetics, etc.

In addition, in the present invention, regarding inorganic oxides that have conventionally been obtained only in the form of particles, we have developed scaly inorganic oxides that have excellent transparency and uniform thickness, and the length of the pieces is very large compared to the thickness. A method of manufacturing an article is provided.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 10 kg of a silicon oxide colloid solution containing various concentrations of silicon oxide colloid with a particle size of 12 mμ obtained by dealkalizing water glass with a cation exchange resin was frozen by varying the freezing time, Next, freeze-drying was performed to obtain scaly hydrated silicon oxide. This was fired at 600'C for 3 hours to produce transparent and flaky silicon oxide by IH. Table 1 shows the relationship between the concentration of silicon oxide in the colloidal solution, the freezing time, and the thickness of 1q scale-like silicon oxide.

Similarly, silicon oxide colloidal particles of 80 mμ were prepared,
Temperature of silicon oxide in colloidal solution, freezing time, j
Table 1 shows the relationship between the q and the thickness of the scale-like silicon oxide.

Table 1 Example 2 10 kg of a titanium oxide colloid solution containing various concentrations of titanium hydroxide colloid with a particle size of 3 Qmμ obtained by hydrolyzing titanyl sulfate was frozen for various freezing times, and then freeze-dried. I did it.

The flaky titanium oxide thus obtained was fired at 600'''C for 3 hours to obtain transparent and flaky titanium oxide.

Table 2 shows the relationship between the concentration of titanium oxide in the colloidal solution, the freezing time, and the thickness of the obtained flaky silicon oxide.

Table 2 Example 3 Aluminum oxide colloid solution 10k containing aluminum oxide colloid with a particle size of 20 mμ at various 6 degrees, obtained by adding acetic acid to aluminum oxide gel and aging at 90°C
c+ was frozen for varying freezing times and then freeze-dried. The resulting flaky hydrated aluminum oxide was calcined at 550'C for 3 hours to obtain transparent and flaky aluminum oxide.

Table 3 shows the relationship between the concentration of aluminum oxide in the colloidal solution, the freezing time, and the thickness of the obtained scaly aluminum oxide.

Table 3 Example 4 Two colloidal solutions of silicon oxide, titanium oxide, and aluminum oxide used in Examples 1 to 3 were selected and mixed in equal amounts to prepare a mixed colloidal solution. This was frozen for a predetermined time and then freeze-dried. The obtained scale-like hydrous oxide was calcined at 600'C for 3 hours to obtain a transparent and scale-like mixed oxide.

Table 4 shows the relationship between the weight ratio of the oxide, the concentration of the colloidal solution, the freezing time, and the thickness of the obtained scaly material.

Example 5 An iron colloidal solution (colloid particle size 10 mμ > 10
kg for 18 minutes, then freeze-drying,
A scale-like hydrated iron oxide was obtained. This was fired at 500° C. for 3 hours to obtain transparent flaky iron oxide with a thickness of 2 μm.

Example 6 10 kg of an antimony solution (colloid particle size 15 mμ) containing 6% antimony obtained by dissolving antimony trioxide in a hydrogen peroxide solution (colloid particle size 15 mμ) was frozen for 30 minutes, and then freeze-dried. A scaly hydrated antimony oxide was obtained. This was baked at 500° C. for 3 hours to obtain transparent, flaky antimony oxide with a thickness of 2.0 μm.

X dust fPJ 7 Tin colloidal solution containing 10% by weight of tin (colloid particle size 15
mμ) to 1! :1 was frozen for 6 minutes and then freeze-dried to obtain scale-like hydrous tin oxide. 650'
C. for 3 hours to obtain transparent, scaly tin oxide with a thickness of 2 μm.

A zirconia colloid solution containing 5% by weight of zircon (colloid particle size 10 mμ > 1k (colloid particle size 10 mμ > 1 k) (colloid particle size 10 mμ > 1 k) is obtained by decomposing a commercially available zirconia gel in acetic acid for 20 minutes, and then freeze-drying it to obtain scales. This was fired at 600° C. for 3 hours to obtain 1 q of transparent, scale-like zirconia oxide with a thickness of 2 μm.

[Brief explanation of the drawing]

Figure 1 shows the freezing time, the oxide temperature in the colloidal solution, and the thickness of the scale-like titanium oxide that is produced when producing scale-like titanium oxide from a hydrous titanium oxide colloidal solution with a colloidal particle size of 30 mμ. FIG. 2 shows the relationship between the freezing time, the temperature of the oxide in the colloidal solution, and the scale of the scale when producing scale-like aluminum oxide from an aluminum oxide colloid solution with a colloidal particle size of 20 mμ. FIG. 3 is a diagram showing the relationship between the thickness of aluminum oxide and the colloidal particle diameter
FIG. 2 is a diagram showing the relationship between the freezing time, the concentration of oxide in the colloidal solution, and the thickness of the flaky silicon oxide to be jqed when producing scaly silicon oxide from a μ silicon oxide colloidal solution. . Patent applicant: Catalysts & Chemicals Industry Co., Ltd. No. 1
Figure freezing time (sec) Figure 2 freezing time (sec)

Claims (4)

[Claims] (1) Made of one or more selected from the group consisting of titanium oxide, silicon oxide, aluminum oxide, iron oxide, zirconium oxide, tin oxide, and antimony oxide.It has excellent transparency and is thin compared to its thickness. Scale-like inorganic oxides or hydrous inorganic oxides with long lengths. (2) The scale-like inorganic material according to claim 1, which has a thickness of 0.05 to 5 μm and a ratio of the thickness to the longest length of the piece (aspect ratio) of 5 or more. Oxides or hydrous inorganic oxides. (3) A colloidal solution of an inorganic oxide, a hydrous inorganic oxide, or both is frozen, and inorganic oxide particles, hydrous oxide particles, or both are precipitated in the gap between the crystal planes of the solvent of the colloidal solution. A method for producing a scaly inorganic oxide or a hydrated inorganic oxide, the method comprising: removing the solvent while maintaining the frozen product at a temperature at which it will not thaw. (4) A patent claim characterized in that the inorganic oxide is one or more selected from the group consisting of titanium oxide, silicon oxide, aluminum oxide, iron oxide, zirconium oxide, tin oxide, and antimony oxide. A method for producing a scaly inorganic oxide or a hydrous inorganic oxide according to item 3.