JP2721705B2 - Sodium hexatitanate fine particle powder and method for producing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fine particles of sodium hexatitanate useful as raw materials for heat-insulating paints and heat-insulating sheets, and as pigments for protecting ultraviolet rays, and to a method for producing the same.

2. Description of the Related Art Japanese Patent Application Laid-Open No. 63-252927 of the present applicant discloses a method for producing fine particles of sodium hexatitanate.

This production method comprises spray-drying a mixed slurry of a titanium raw material compound and a sodium raw material compound blended in a ratio represented by the general formula Na ₂ O · nTiO ₂ (n = 2 to 4) to obtain fine particles of sodium titanate. And then immersing the granular product in water or warm water to separate the sodium titanate fine particles into single particles, and then adding an acid to the slurry to adjust the pH to 7.5 to 8.5. By adjusting, the composition of the sodium titanate fine particles is Na ₂ O.6TiO ₂ .nH ₂ O
It is characterized in that it is subjected to a composition conversion process so that

However, in the method disclosed in this prior art, 10
It is not possible to obtain fine sodium hexatitanate particles having a specific surface area of m ² / g or more, and when used in heat-insulating paints and heat-insulating sheets, sufficient properties can be imparted unless the amount added is large. There was a problem that it could not be done. Furthermore, despite the fact that sodium hexatitanate has the basic physical property that the reflectance of ultraviolet rays is higher than that of anatase-type titanium oxide, the prior art obtains an ultrafine powder having a specific surface area of 30 m ² / g or more. It could not be applied to UV protection pigments.

Problems to be Solved by the Invention As described above, the sodium hexatitanate fine particle powder obtained by the conventional production method is not preferable as a raw material for a heat-insulating paint, a heat-insulating sheet or the like, or as a UV protection pigment.

Therefore, an object of the present invention is to provide a sodium hexatitanate fine particle powder having a specific surface area of 10 m ² / g or more and having good dispersibility, and a method for producing the same, for the above-mentioned applications.

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, a titanium raw material compound and a sodium raw material in which the molar ratio of TiO ₂ : Na ₂ O is blended at a ratio of 6: 1. After spray-drying the mixed slurry with the compound, the mixture is calcined at 600 to 1000 ° C. to produce granules which are secondary particles of sodium titanate fine particles, and then the granules are wet-pulverized to primary particles. Thus, the present inventors have discovered that fine particles of sodium hexatitanate having a specific surface area of 10 m ² / g or more can be obtained, thereby completing the present invention.

That is, the present invention provides fine particles of sodium hexatitanate having a specific surface area of 10 m ² / g or more.

Further, the present invention spray-drys a mixed slurry of a titanium raw material compound and a sodium raw material compound in which the molar ratio of TiO ₂ : Na ₂ O is 6: 1, and then calcinates the mixture at 600 to 1000 ° C. To produce granules that are secondary particles of sodium hexatitanate fine particles, and then wet-pulverize the granular product to form fine primary particles. A manufacturing method is provided.

Examples of the titanium raw material compound used in the present invention include titanium dioxide and hydrous titanium oxide.Examples of the sodium raw material compound are compounds that generate Na ₂ O during firing, such as Na ₂ O, NaOH, Na ₂ CO, and NaHCO. ₃ , Na ₂ C ₂ O ₄ , NaNO
_{3 and the} like.

The firing temperature is from 600 to 1000 ° C, preferably from 650 to 900 ° C. That is, if the firing temperature is higher than 1000 ° C., 10 m ² / g
Not only is it difficult to obtain a sodium hexatitanate fine particle powder having the above specific surface area, but also it is difficult to make a single particle even by performing the wet grinding in the next step, and the dispersibility of the sodium hexatitanate fine particles is good. No powder is obtained. On the other hand, if the calcination temperature is lower than 600 ° C., the reaction rate is too low to be practical. The firing time is 0.5 to 5 hours, preferably 1 to 3 hours.
Time.

The operation of converting the granular product into primary particles of sodium hexatitanate is performed by a known wet pulverizer.
It is possible to make a single particle with a grinding time of hours.

The obtained sodium hexatitanate fine particles have a specific surface area of 10 m ² / g or more, and the average particle size is about 0.01 to 0.5 μm.

When firing the blended mixture of the titanium raw material compound and the sodium raw material compound, Na ₂ SO ₄ , K ₂ SO ₄ , NaCl and KCl
When one or two or more kinds of fluxes selected from the above are mixed in the above-mentioned mixture and fired, the reaction can be completed in a shorter time as compared with the case where they are not mixed, and the pulverization time of the next step is also reduced. Can be shortened. Note that the addition ratio of the above components is 5% with respect to the mixture.
The following is appropriate, and even if it is added in an amount of more than 5%, the above-mentioned effect is not increased.

Hereinafter, the present invention will be described in more detail with reference to Examples.
The following examples are provided for illustrative purposes only, and are not intended to limit the scope of the invention.

Example 1 Hydrous titanium oxide slurry containing 29.1% TiO _{2 and} 1% SO ₃
While stirring 2000 g, 155 g of sodium carbonate powder was added. The slurry is heated at an inlet temperature of 250-260 ° C and an outlet temperature of 90.
Spray-dried under the condition of 100 ° C. Next, the dried product was placed in an alumina crucible and heated in an electric furnace at a heating rate of 200 ° C. /
After firing at 700 ° C. and a holding temperature of 3 hours, the temperature was lowered at a rate of 200 ° C./hour.

The fired product was put into warm water of 8 in a stainless steel container, stirred for 1 hour with a homomixer, and then overwashed.
Next, the washed cake was re-dispersed in 8 pieces of water and wet-pulverized for 2 hours using an alumina ball mill.

When this product was examined using an area meter and an X-ray diffractometer, it was found to be a single phase of sodium hexatitanate having a specific surface area of 35 m ² / g.

Example 2 1000 g of anatase type titanium oxide and 221 g of sodium carbonate
Was weighed, added to 2.5 water, and stirred well. This slurry was spray-dried under the same conditions as in Example 1. This dried product is placed in an alumina crucible and heated in an electric furnace at a heating rate.
After firing at 200 ° C./hour, a firing temperature of 900 ° C. and a holding temperature of 2 hours, the temperature was lowered at a rate of 200 ° C./hour.

The fired product was put into 15 pieces of water in a stainless steel container, dispersed, and then wet-pulverized for 6 hours using an alumina ball mill.

When this product was examined using an area meter and an X-ray diffractometer, it was found to be a single phase of sodium hexatitanate having a specific surface area of 23 m ² / g.

Example 3 1000 g of anatase type titanium oxide, sodium 221
g, 12.7 g of potassium chloride and 9.9 g of sodium chloride were weighed, and after adding water of 2.5, the mixture was thoroughly stirred. This slurry was spray-dried under the same conditions as in Example 1. Next, the dried product was placed in an alumina crucible and heated in an electric furnace at a heating rate.
After firing at 150 ° C / hour, firing temperature of 750 ° C, and holding temperature of 2 hours, the temperature was lowered at a rate of 200 ° C / hour.

The fired product was put into 13 hot water in a stainless steel container, stirred for 1 hour with a homomixer, and then overwashed.
Next, the washed cake was re-dispersed in 13 pieces of water and wet-pulverized for 2 hours using an alumina ball mill.

When this product was examined using an area meter and an X-ray diffractometer, it was found to be a single phase of sodium hexatitanate having a specific surface area of 12 m ² / g.

Comparative Example 1000 g of anatase-type titanium oxide and 442 g of sodium carbonate
Was weighed, and after adding water of 2.5, the mixture was stirred well. The slurry was spray-dried at an inlet temperature of 250 to 260 ° C and an outlet temperature of 90 to 100 ° C. Next, the dried product was placed in an alumina crucible and heated in an electric furnace at a heating rate of 200 ° C./hour and a firing temperature of 8 ° C.
After firing at the condition of 00 ° C. and a holding temperature of 4 hours, the temperature was lowered at a rate of 200 ° C./hour.

The fired product was put into warm water of 10 in a stainless steel container, immersed for 3 hours, and then stirred for 1 hour with a homomixer.
After adjusting the pH of the slurry to 7.8 by adding 4N-sulfuric acid dropwise,
After overwashing, it was baked at 800 ° C. for 1 hour.

The product was examined using an area meter and an X-ray diffractometer, and was found to be a single phase of sodium hexatitanate having a specific surface area of 5 m ² / g.

3 parts by weight of the products obtained in Example 1 and Comparative Example were added to 100 parts by weight of a polyvinyl chloride-based resin paint having the compounding ratio shown in Table 1 and dispersed, and then applied to a polyester film,
The transmittance at a wavelength of 300 to 400 nm was measured. First transmittance curve
Shown in the figure. From this figure, it can be seen that the product according to Example 1 of the present invention has an excellent ultraviolet shielding effect.

Table ¹ PVC resin ¹⁾ 17.8g MIBK ²⁾ 33.8g Toluene 46.0g DOP ³⁾ 1.8g 1) S-Lec-C-5 2) Sekisui Chemical Co., Ltd. 2) Methyl isobutyl ketone 3) Dioctyl phthalate Effect Sodium hexatitanate synthesized according to the present invention is 10 m ²
Since it is a fine particle powder having a specific surface area of / g or more, it is useful as a raw material for heat-insulating paints, heat-insulating sheets, ceramics and the like, and as a pigment for protecting UV rays.

[Brief description of the drawings]

FIG. 1 is a transmittance curve of a film obtained by coating the products obtained in Example 1 and Comparative Example with a polyvinyl chloride resin, and then applying the resultant to a polyester film.

Claims (3)

(57) [Claims] 1. A sodium hexatitanate fine particle powder having a specific surface area of 10 m ² / g or more. 2. A mixed slurry of a titanium raw material compound and a sodium raw material compound, which is mixed at a molar ratio of TiO ₂ : Na ₂ O of 6: 1, is spray-dried and then calcined at 600 to 1000 ° C. A method for producing fine particles of sodium hexatitanate, which comprises producing granules, which are secondary particles of sodium titanate fine particles, and then forming the granules into primary particles by wet grinding. 3. A mixed slurry of a titanium raw material compound and a sodium raw material compound mixed in a molar ratio of TiO ₂ : Na ₂ O of 6: 1, Na ₂ SO ₄ , K ₂ SO ₄ , NaCl and After spray-drying a mixture of one or two or more fluxes selected from KCl, the mixture is calcined at 600 to 1000 ° C. to produce granules which are secondary particles of sodium titanate fine particles, and then the granules are formed. A method for producing sodium hexatitanate fine particle powder, comprising subjecting a material to primary particles by wet grinding.