JP2852825B2 - Method for producing flaky potassium hexatitanate polycrystalline particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, paint pigments, films, coating compositions, potassium hexatitanate have useful flake shape as a constituent material of cosmetics polycrystalline grains child
And a method for producing the same.

[0002]

_2. Description of the Related Art Potassium hexatitanate (K ₂ Ti
₆ O ₁₃ ) is a synthetic inorganic material having abrasion resistance, fire / heat resistance, heat insulation, reinforcing properties, and the like, and is expected to be used as an asbestos substitute for industrial applications in various fields.

[0003] Potassium hexatitanate is obtained by using, as a starting material, a mixed powder of a titanium compound which becomes titanium dioxide (TiO ₂ ) by heating and a potassium compound which becomes potassium oxide (K ₂ O) by heating, and cools the heated melt. After being solidified, it is manufactured by subjecting it to a depotassium treatment or a baking treatment. Various proposals have been made for the improvement of the manufacturing method, and as examples of industrial applications, reinforcing materials for plastic molded products, friction materials such as brake pads, heat-resistant and fire-resistant materials such as furnace wall linings, filter materials for filtration, etc. (JP-A-61-6)
No. 3553, No. 61-186600, No. 61-19
No. 1599).

[0004]

The industrial application of potassium hexatitanate to date is mainly intended for applications requiring fire resistance, heat resistance, heat insulation, abrasion resistance, etc., and is mainly used as fibers. The intention was that the synthesis method also focused on improving the fiber morphology.

According to the present invention, as a result of conducting various studies for more effective use of potassium hexatitanate in various aspects, the flaky polycrystalline particles obtained by controlling the conditions of the synthesis treatment are replaced with the conventional fiber. It has been found that the material has optical characteristics different from those of shapes and is suitable for pigments, films, coating compositions and the like. The present invention has been made based on this finding.

[0006]

SUMMARY OF THE INVENTION A slice of the present invention
The method for producing the polycrystalline potassium hexatitanate particles comprises heating
A titanium compound which becomes titanium dioxide (TiO ₂ )
Potassium compound which becomes potassium oxide (K ₂ O) by heating
And things, the molar ratio of TiO ₂ / K ₂ O is 1.5 to 2.5
So that the coloring element can be used alone or
The mixture added as an oxide is used as a starting material and heated.
Fibrous potassium dititanate by directional solidification of melt
A solid consisting of crystals is obtained, and the solid is subjected to depotassium treatment.
To make potassium dititanate equivalent to potassium hexatitanate
Converting the hydrated potassium titanate, the de-potassium treatment
During or after processing, wet grinding
Pulverized into flaky particles 1-100 μm thick and 0.01-2 μm thick
The dewatered and dried pulverized material is then fired.
It is a sign. Flaky hexatitanic acid obtained by the present invention
The potassium polycrystalline particles are wet-ground in the above process.
Substantially the same as the hydrated potassium titanate flake particles.
It has a uniform size and thickness. The average size is
It is a value obtained by dividing the sum of the flaky maximum length I and the minimum length I by two.

The flaky potassium hexatitanate polycrystalline particles of the present invention (hereinafter also simply referred to as “flaky particles”) have high reflectance and high refractive index in a wide wavelength range from ultraviolet light to infrared light. have. The flaky particles of the present invention may optionally contain a coloring element such as Co, Fe, Cu, V, N
A chemical composition containing i, Mn, etc. is provided. The flaky particles of the present invention in the case of not containing a coloring element are white particles excellent in concealing properties, and the particles to which the coloring element is added have a change in an absorption band generated in a visible light region. Green by addition, yellow by addition of V or Ni, F
It has a color tone such as brown by addition of e and gray by addition of Mn.

Further, the flaky particles of the present invention have excellent spreadability, adhesion, concealing properties, etc. required when they are used as an additional component of paints and film / coating compositions.

Further, the flaky particles of the present invention have good fire and heat resistance, wear resistance, lubricity and the like as characteristics of potassium hexatitanate crystals.

The reason why the lower limit of the average size of the flaky particles of the present invention is set to 1 μm is that if the size is smaller than that, the reflectivity becomes lower and sufficient gloss cannot be secured. The reason for this is that, when the composition is coarser than that, the dispersibility, workability, weather resistance, etc. in forming the coating composition and the like deteriorate. Preferably, 5 to 60 μm
It is. Further , the reason why the thickness is limited to 0.01 to 2 μm is that if the thickness is thinner, the mechanical strength is poor, and if it is thicker, the smoothness of the film surface is reduced when the film is used for a film coating composition, a cosmetic or the like. Is worse. Preferably, it is 0.01-1 μm.

[0011] flaky potassium hexatitanate polycrystalline particles of the present invention comprises a titanium compound comprising titanium dioxide (TiO ₂₎ by heating, and a potassium compound as the potassium oxide (K 2 _O) by heating, TiO ₂ / K ₂ O as a starting material by mixing so as to have a molar ratio of about 1.5 to 2.5,
The heated melt is subjected to directional cooling to obtain a cooled solidified mass (solidified material) composed of fibrous potassium dititanate crystals generated as an initial phase, and the solidified material has a composition (TiO 2) equivalent to potassium hexatitanate. ₂ / K ₂ O: about 6), after depotassium treatment to elute K ⁺ ions and wet pulverization for pulverization into flakes of a predetermined size, dehydrated and dried, Then, it is manufactured by firing.

Various titanium compounds such as purified titanium oxide, synthetic rutile, titanium slag, natural rutile sand and natural anatase sand are used as the titanium compound which becomes titanium dioxide by heating, which is one of the constituents of the starting material. The potassium compound to be compounded in the titanium compound is typically potassium carbonate (K ₂ CO ₃ ), and in addition, hydroxide, nitrate and the like can be used.

A starting material is obtained by mixing a titanium compound and a potassium compound. Is to 1.5 to 2.5 in the mixing ratio _TiO 2 _{/ K} 2 O (molar ratio), the molten product crystals potassium dititanate as initiation phase from _(K 2 _Ti 2 O
₅ ) is to be generated efficiently. When flaky particles are produced as colored particles, a coloring element is added to the starting material mixture. The coloring element may be added alone or as an oxide. The addition amount is, for example, about 0.1 to 10% by weight (in the case of an oxide, an element conversion value).

The starting material is heated and melted, and the heated melt is subjected to unidirectional or multidirectional directional cooling to solidify, thereby obtaining a fibrous solidified product of potassium dititanate crystals. Due to its crystal structure, the cooled solidified product composed of potassium dititanate crystals efficiently dissolves K ⁺ ions for adjusting the TiO ₂ / K ₂ O molar ratio and pulverizes into flaky particles by wet pulverization. Can do well.

[0015] The depotassium treatment of the solidified product is carried out by using water (normal temperature), heated water (about 50 to 80 ° C), or various acid aqueous solutions, for example, about 0.05 to 0.3% sulfuric acid aqueous solution, about 0 to 0.3% sulfuric acid aqueous solution. 0.05 to 0.3% hydrochloric acid, about 0.1 to 1% acetic acid aqueous solution or the like can be used as the treatment liquid. By this potassium removal treatment, K ⁺ ions are eluted until the molar ratio of TiO ₂ / K ₂ O becomes about 6, and the potassium dititanate crystal in the primary phase is made of titanium hydrate having a chemical composition equivalent to potassium hexatitanate. Convert to potassium acid. The elution amount of K ⁺ ion is
It can be adjusted by the amount of the processing solution used, the processing time, and the like. In order to increase the efficiency of the treatment, a stirring flow is added to the treatment liquid by a propeller or the like as necessary.

The solid to be subjected to the depotassium treatment is K ⁺
Although a certain degree of pulverization occurs with the elution of soluble substances such as ions, it is not possible to pulverize to flaky particles of a required size by itself. To obtain flaky particles, a wet pulverization process is required. The wet pulverization treatment can be performed in the treatment process in parallel with the depotassium treatment,
Alternatively, it may be performed after the potassium removal treatment. As the medium at the time of pulverization, water, various acid aqueous solutions, organic solvents (for example, alcohols), salt aqueous solutions, and the like can also be used. Wet pulverization can also be carried out using a household mixer, mortar or the like, and as other effective pulverization means, an emulsifying / dispersing machine, a wet ball mill or the like is used. The amount of the medium in the wet milling may be about 20 to 250 times (weight ratio) the solidified material processing amount.

In the above wet pulverization treatment, hydrated and swollen potassium dititanate crystals (the chemical composition after depotassium treatment has changed to a composition equivalent to potassium hexatitanate,
(The crystal structure keeps the stratification of the layered structure of potassium dititanate.) Cleavage and exfoliation occur and powders into flaky particles. This makes the average size 1 to 100 μm and thickness
The flaky particles of 0.01 to 2 μm are collected, dehydrated and dried.

The chemical composition of the flaky particles obtained through the above depotassium treatment and wet grinding treatment corresponds to that of potassium hexatitanate, but the crystal structure of the precursor potassium dititanate ( Since it has a band (layered structure), it is converted into a crystal structure (tunnel structure) of potassium hexatitanate. This structural transformation is performed at a temperature of about 700-10.
This is achieved by a calcination treatment at 00 ° C (preferably about 900 ° C). This results in flaky particles composed of potassium hexatitanate crystals that are complete in both composition and structure.

It is needless to say that the flaky particles obtained by the present invention can be used as they are as pigments for paints or as components of compositions such as films and coating materials, but the surface of the particles is subjected to an appropriate treatment. Function can be further added. Examples of the surface treatment include, for example, treatment for imparting conductivity by vapor deposition of tin and improving dispersibility.

[0020]

EXAMPLES Example 1 [I] Starting material Purified titanium oxide powder (purity 99) as a titanium compound
%), And industrial potassium carbonate powder (purity: 99%) as a potassium compound. TiO ₂ / K ₂ O (molar ratio):
About 2.

[II] Heat Melting and Cooling Solidification The starting materials are put into a platinum crucible and heated and melted (1100 ° C. ×
40 minutes). The melt is poured into a metal cooling dish, and directional solidification is performed upward from the bottom surface of the cooling dish to obtain a solidified product composed of fibrous potassium dititanate crystals.

[III] Depotassium treatment and wet pulverization treatment The solidified product is immersed in 200 times (weight) water (normal temperature), and depotassium treatment is required for 5 hours while stirring with a propeller. Next, the wet pulverization process was performed for 10 minutes using a household mixer.

[IV] Firing Treatment After the wet pulverization, the pulverized material recovered from the liquid was dehydrated and dried (air-dried), then placed in an alumina crucible and fired in a furnace maintained at 900 ° C. for 3 hours.

The obtained particles consist of potassium hexatitanate crystals (by X-ray diffraction) and have an average size of about 30 μm.
These are white particles having a flaky shape having a thickness of about 0.3 μm (by a scanning electron microscope) and having excellent gloss.

Example 2 Co oxide (Co ₃ O ₄ ) as a coloring element as a starting material
Except that 0.5% by weight of powder (in terms of Co) was added.
Under the same conditions as in Example 1, flaky particles (average size: about 30 μm, thickness: about 0.3 μm) composed of potassium hexatitanate crystals were obtained. This is a bright green particle with gloss.

Example 3 Except that natural rutile sand (purity: 95%) was used as a titanium compound and 5% of metallic Ni powder was added as a coloring element to use as a starting material, the same procedure as in Example 1 was repeated. Flaky particles of potassium titanate crystals (average size: about 3
0 μm and thickness: about 0.3 μm). These are bright yellow particles with a gloss.

[0027]

EFFECTS OF THE INVENTION The flaky potassium hexatitanate polycrystalline particles of the present invention can be used as paint pigments for various paints (for example, for top coating of automobiles), film compositions and cosmetic compositions due to their optical properties. It is useful as a constituent material or the like. In addition, due to the heat resistance and heat insulation properties of potassium hexatitanate as properties, it is used as a heat insulating paint composition / coating composition, or as a constituent material of a lubricant or a lubricating paint composition, etc. utilizing good sliding properties. Useful.

Claims (1)

(57) [Claims] 1. A titanium compound which becomes titanium dioxide (TiO ₂ ) by heating and potassium oxide (K ₂ O) by heating
A potassium compound as the molar ratio of TiO ₂ / K ₂ O were mixed so that 1.5 to 2.5, the mixture was added a coloring element as a single or an oxide thereof as a starting material if desired, the molten product To obtain a solidified product consisting of fibrous potassium dititanate crystals, and subject the solidified product to depotassium treatment to convert potassium dititanate to hydrated potassium titanate equivalent to potassium hexatitanate. During or after the potassium removal treatment, a wet pulverization treatment is performed to obtain an average size of 1 to 100 μm and a thickness of 0.01 to 2 μm.
A method for producing flaky potassium hexatitanate polycrystalline particles, comprising: pulverizing the flakes into particles; dehydrating and drying the crushed material;