JP2981791B2 - Production method of barium sulfate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing barium sulfate, which has a large particle size, is excellent in usability and concealment, has high light scattering and transparency, and is useful as an extender for cosmetics.

[0002]

2. Description of the Related Art Barium sulfate is harmless to the human body and highly opaque, and is therefore widely used industrially as an X-ray contrast agent, a γ-ray absorber, a white pigment, and the like. However, when used for cosmetics, and especially when used for foundations and the like, conventional barium sulfate has poor extensibility and adhesiveness, and lacks a feeling of use. In addition, they have a defect that they lack transparency and their skin feel is poor after makeup. As means for solving the above drawbacks, Japanese Patent Application Laid-Open No. Sho 58-4
Japanese Patent No. 1718 discloses a method of increasing the particle size of barium sulfate, and Japanese Patent Application Laid-Open No. Sho 62-174238 discloses a method of making the crystal form of barium sulfate into a plate or needle. However, all of these post-synthesis heat treatments,
The production process is complicated due to the need for mineral acid treatment, which is not preferable in industrial production. In general, many studies have been reported on the generation of barium sulfate crystals and the growth of the crystals by immersion under heating. For example,
According to Bull. Chem. Soc. Japan Vol.27 No.3 page 121,
A barium salt aqueous solution and a sulfuric acid aqueous solution were quickly mixed in a large test tube, and the obtained precipitate was observed and measured by an electron microscope.As a result, the size and shape of the particles were controlled by the concentration of the mixed raw material.
As the concentration decreases, the particles are variously deformed into an amorphous type, a spherical type, a spindle type, a diamond type and the like, and the average size of the particles is 0.1.
It is shown that it varies greatly from 013 μm to about 2 μm. When barium sulfate is used in a foundation or the like, coarse particles are preferable from the viewpoint of its use.However, since the generation region of the coarse particles is an extremely unstable region, reproducibility is poor, and there is a drawback that the dispersion of particles is remarkable. Was.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for producing barium sulfate having a large particle size and high light scattering and transparency.

[0004]

Under these circumstances, the present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, the present inventors have found that a reaction raw material for synthesizing barium sulfate, a reaction solution concentration, a reaction temperature, and a common reaction temperature. The conditions such as ion concentration and reaction operation factors were clarified in detail and quantitatively, and a method for stably producing transparent and coarse barium sulfate having a light scattering effect meeting the above objectives was established. Completed the invention.

That is, the method for producing barium sulfate of the present invention comprises the steps of (a)
The reaction is performed under the condition (c). (A) a 0.001-0.1 mol / l barium compound solution and a sulfate compound solution are reacted at a molar ratio of the barium compound to the sulfate compound of 0.1 to 5; The dropping time for adding either one to the other is 2 seconds to 7 minutes, and (c) the pH of the reaction system is 0.5 to 10.

The barium compound used in the present invention is soluble in a solvent such as water or alcohol, and examples thereof include barium hydroxide and barium chloride, barium sulfide, barium nitrate, and barium salts of barium acetate. .
Of these, barium hydroxide, barium chloride, barium nitrate, and barium acetate are preferred. Further, barium hydroxide and barium chloride are most preferred because of easy handling and availability of by-products produced by the reaction. Further, the sulfate compound used in the present invention is soluble in a solvent such as water or alcohol, and examples thereof include sulfuric acid, sodium sulfate, sodium hydrogen sulfate, ammonium sulfate, potassium sulfate, and lithium sulfate. Among them, sulfuric acid, sodium sulfate, sodium hydrogen sulfate and ammonium sulfate are preferred, but sulfuric acid is most preferred in terms of availability and price. These barium compounds and sulfate compounds may be used alone or in combination of two or more.

The barium compound and the sulfate compound are dissolved in a solvent such as water and alcohol to be used as a barium compound solution and a sulfate compound solution. The barium ion concentration of the barium compound solution and the sulfate ion of the sulfate compound solution are used. The concentrations are 0.001 to
It must be 0.1 mol / l. When the concentration is less than 0.001 mol / l, the crystal growth becomes insufficient due to low supersaturation, and coarse particles cannot be obtained. If the concentration exceeds 0.1 mol / l, nucleation occurs instantaneously due to the extremely high degree of supersaturation, and only ultrafine crystals of submicron or less can be obtained. The most preferred concentration is between 0.005 and 0.03 mol / l.

The molar ratio between the barium compound and the sulfate compound is 0.1 to 5 (barium compound / sulfate compound =
1/10 to 5/1).

As a reaction method, one of the barium compound solution and the sulfuric acid compound solution is placed in a reaction tank, and the other is dropped into the reactor with stirring for 2 seconds to 7 minutes to cause a reaction. At this time, if the dripping time is less than 2 seconds, the reaction system suddenly becomes supersaturated, so that the inside of the reaction system becomes unstable, sudden nucleation occurs, and barium sulfate crystals become ultrafine. Also, if the dropping time exceeds 7 minutes,
In the first half of charging, the number of nuclei of barium sulfate is very small, so that nuclei are more easily generated than in crystal growth, and the number of nuclei increases, so that coarse particles are hardly obtained. That is, in order to obtain barium sulfate having a large particle size, the dropping time is 2 seconds to 7 seconds.
Minutes is preferred, and 5 seconds to 3 minutes is particularly preferred.

At this time, the pH of the reaction system is adjusted to 0.5 to 1
It is important to keep it at zero. That is, various barium compounds and sulfuric acid compounds are considered as reaction raw materials, and barium sulfate can be formed in any combination. For example, a barium hydroxide solution is prepared by combining barium hydroxide and sulfuric acid. When the sulfuric acid solution is added dropwise, the pH in the reaction system gradually decreases from a state exceeding 10 as the sulfuric acid solution is added dropwise.
Barium sulfate thus produced has a low light scattering intensity and is not suitable for the purpose of the present invention. On the other hand, when the sulfuric acid solution is taken in the reaction tank and the barium solution is dropped,
In order to satisfy the above conditions, coarse barium sulfate particles having high light scattering intensity and light transmittance can be obtained. If the pH is 0.5 or less, the resulting barium sulfate has a low light transmittance, which is not preferable. Thus, the pH of the reaction system affects the light scattering intensity of the obtained barium sulfate. Therefore, the pH of the reaction system is an important factor in the present invention, together with the dropping time and the reaction concentration.

The reaction temperature can be from 60 ° C. to 120 ° C., but the higher the reaction temperature, the higher the light scattering intensity of the obtained barium sulfate. However, 100
If the temperature is higher than 60 ° C, 60 ° C or higher,
100 ° C. or less is desirable. In practicing the method according to the invention, various types may be employed in relation to the reactor without departing from the scope of the invention.

According to the present invention, coarse barium sulfate having an average particle size of 4 to 20 μm can be produced. When it is used for a foundation or the like, if the average particle size is less than 4 μm, elongation at the time of application is poor, and a bulky feeling appears. Also 2
If it exceeds 0 μm, the feeling of roughness becomes strong and the feeling of use is inferior. Further, according to the present invention, barium sulfate having a light scattering intensity of 50% or more and a light transmittance of 70% or more can be obtained. When the light scattering intensity is 50% or more, the light diffusion property is high and the light transmittance is 7%.
When the content is 0% or more, transparency is excellent, and barium sulfate having these properties is useful as an extender for cosmetics.

[0013]

The present invention will be further described with reference to examples and comparative examples. In the examples and comparative examples, the average particle size, light scattering intensity, and total light transmittance were evaluated as follows. The barium sulfate slurry with the average particle size synthesized is cooled to room temperature, and
After filtration through a filter paper of C, washing with ion exchanged water and drying at 105 ° C. for 3 hours, barium sulfate powder is obtained. Further, this powder was photographed with an electron microscope, the length of the longest part of the crystal was measured, and the average value was defined as the average particle size. Light scattering intensity and total transmittance The synthesized barium sulfate is cooled to room temperature, filtered through 5C filter paper, washed with ion-exchanged water, and dried at 105 ° C. for 3 hours to obtain barium sulfate powder. Next, using silicon oil as a dispersion medium, this barium sulfate powder was added at 20 wt%.
In addition, the mixture is uniformly kneaded, and a thin film of 15 μm is formed into a glass plate by an applicator. Further, this was measured using a haze meter [manufactured by Murakami Color Research Laboratory (model: HR-10).
0)], the parallel light transmittance (Tp) and the scattered light transmittance (Td) were measured, and [Tp + Td] was calculated as the total light transmittance, [T
d / (Tp + Td)] × 100 was defined as the light scattering intensity.

Example 1 1.71 g of a special grade reagent barium hydroxide and 0.98 g of a special grade reagent sulfuric acid were respectively dissolved in 1000 g of ion-exchanged water, and a 0.01 mol / l barium solution and 0.01 mol / l were dissolved.
l of sulfuric acid solution. Next, a sulfuric acid solution was charged into a 2 liter flask and stirred at 200 rpm with a Teflon paddle.
After heating to 0 ° C, the barium solution heated to 100 ° C was
It was thrown in at 0 seconds. Then, after continuing stirring for 3 minutes, the reaction was terminated. The pH during the reaction was between 1.5 and 7. Next, the mixture was cooled to room temperature, filtered through 5C filter paper, washed with ion-exchanged water, and dried at 105 ° C. for 3 hours to obtain 2.1 g of barium sulfate powder. The powder thus obtained is
The average particle size is 11.2 μm, and the light scattering intensity is 69.5.
%, And the total light transmittance was 91.1%. Also, when added to the foundation, which is a cosmetic, conventional mica,
The feeling of use was good, and the transparency of the decorative film was high, as compared with those containing an extender such as talc.

Example 2 3.42 g of barium hydroxide, a special grade reagent, was added to deionized water 1
A 0.02 mol / l barium solution suspended in 2,000 g and a special grade reagent 1.96 g of sulfuric acid were dissolved in 1000 g of ion-exchanged water to prepare a 0.02 mol / l sulfuric acid solution.
A 1-liter flask was charged with a sulfuric acid solution, stirred with a Teflon paddle at 200 rpm, heated to 100 ° C., and charged with a barium solution heated to 100 ° C. for 2 minutes. Then, after continuing stirring for 3 minutes, the reaction was terminated. The pH during the reaction was 1.
From 5 to 7.0. Then, cool to room temperature, 5C
And then washed with ion-exchanged water.
Drying at 3 ° C. for 3 hours gave 4.5 g of barium sulfate powder. The powder thus obtained had an average particle size of 4.5 μm, a light scattering intensity of 60.3% and a total light transmittance of 88.7%. Further, when it was blended into a foundation, which is a cosmetic, the feeling of use was good and the transparency of the decorative film was high, as compared with those in which conventional extenders such as mica and talc were blended.

Example 3 2.08 g of a special grade reagent barium chloride and 0.98 g of a special grade reagent sulfuric acid were dissolved in 2000 g of ion-exchanged water, respectively, and a 0.005 mol / l barium solution and 0.005 mol
l / l sulfuric acid solution. Next, a sulfuric acid solution was charged into a 5-liter flask, and stirred at 200 rpm with a Teflon paddle.
After heating to 80 ° C, the barium solution heated to 80 ° C was added to 1
It was thrown in at 0 seconds. Then, after continuing stirring for 3 minutes, the reaction was terminated. The pH during the reaction was 2 to 2. Then
The mixture was cooled to room temperature, filtered through 5C filter paper, washed with ion-exchanged water, and dried at 105 ° C. for 3 hours to obtain 2.2 g of barium sulfate powder. The powder thus obtained had an average particle size of 8.5 μm, a light scattering intensity of 62.4%, and a total light transmittance of 90.5%. In addition, when blended into a foundation as a cosmetic, the feeling of use was good and the transparency of the decorative film was high as compared with the conventional blends containing extenders such as mica and talc.

Example 4 8.32 g of special grade reagent barium chloride and 0.98 g of special grade reagent sulfuric acid were respectively dissolved in 1000 g of ion-exchanged water, and a 0.04 mol / l barium solution and 0.01 mol / l
l of sulfuric acid solution. Next, a barium solution was charged into a 2 liter flask, and stirred at 200 rpm with a Teflon paddle.
After heating to 100 ° C, add sulfuric acid solution heated to 100 ° C
It was thrown in at 0 seconds. Then, after continuing stirring for 3 minutes, the reaction was terminated. The pH during the reaction was between 7 and 2. Then
The mixture was cooled to room temperature, filtered through 5C filter paper, washed with ion-exchanged water, and dried at 105 ° C. for 3 hours to obtain 2.2 g of barium sulfate powder. The powder thus obtained had an average particle size of 6.4 μm, a light scattering intensity of 61.5% and a total light transmittance of 87.3%. In addition, when blended into a foundation as a cosmetic, the feeling of use was good and the transparency of the decorative film was high as compared with the conventional blends containing extenders such as mica and talc.

Example 5 1.71 g of barium hydroxide and 0.98 g of sulfuric acid of special grade were dissolved in 1000 g of ion-exchanged water, respectively, and a 0.01 mol / l barium solution and 0.01 mol / l of barium solution were dissolved.
l of sulfuric acid solution. Next, a barium solution was charged into a 2 liter flask, and stirred at 200 rpm with a Teflon paddle.
After heating to 60 ° C., the barium solution heated to 60 ° C.
It was thrown in seconds. Then, after continuing stirring for 3 minutes, the reaction was terminated. The pH during the reaction was between 1.7 and 7.0. Next, the mixture was cooled to room temperature, filtered through 5C filter paper, washed with ion-exchanged water, and dried at 105 ° C. for 3 hours to obtain 2.2 g of barium sulfate powder. The powder thus obtained has an average particle size of 13.3 μm and a light scattering intensity of 55.
The light transmittance was 2% and the total light transmittance was 91.3%. Further, when it was blended into a foundation, which is a cosmetic, the feeling of use was good and the transparency of the decorative film was high, as compared with those in which conventional extenders such as mica and talc were blended.

Comparative Example 1 2.08 g of special grade reagent barium chloride and 0.98 g of special grade reagent sulfuric acid were dissolved in 20 kg of ion-exchanged water, respectively.
0.0005 mol / l barium solution and 0.0005 mol
l / l sulfuric acid solution. Next, a sulfuric acid solution was charged into a 50-liter reaction tank, stirred at 200 rpm with a paddle, heated to 30 ° C., and a barium solution heated to 30 ° C. was charged in 60 seconds. Then, after continuing stirring for 3 minutes, the reaction was terminated. The pH during the reaction was 3 to 3. Next, the mixture was cooled to room temperature, filtered through 5C filter paper, washed with ion-exchanged water, and dried at 105 ° C. for 3 hours to obtain 2.1 g of barium sulfate powder. The powder thus obtained was an undeveloped fine crystal having an average particle size of 1.2 μm and a crystal structure, and had a light scattering intensity of 31.3% and a total light transmittance of 88.7%. Also, when blended into the foundation, which is a cosmetic,
Because of the fine particles, the feeling of use was poor, and the powder was poor in extensibility.

Comparative Example 2 1.71 g of a special grade reagent barium hydroxide and 1.42 g of a special grade reagent sodium sulfate were dissolved in 1000 g of ion-exchanged water, respectively.
A 1 mol / l sulfuric acid solution was prepared. Next, a barium solution was charged into a 2 liter flask, and 200 rpm using a Teflon paddle.
After heating to 100 ° C., a sulfuric acid solution heated to 100 ° C. was added dropwise over 5 minutes. Then, after continuing stirring for 3 minutes, the reaction was terminated. The pH during the reaction was constant at 13. Next, the mixture was cooled to room temperature, filtered through 5C filter paper, washed with ion-exchanged water, and dried at 105 ° C. for 3 hours to obtain 2.2 g of barium sulfate powder. The powder thus obtained has an average particle size of 3.2 μm and a light scattering intensity of 4 μm.
The light transmittance was 1.9% and the total light transmittance was 89.3%. In addition, when blended into a foundation, which is a cosmetic, the powder had poor usability and poor light scattering properties, and was inferior as a cosmetic.

COMPARATIVE EXAMPLE 3 2.08 g of a special grade reagent barium chloride and 0.98 g of a special grade reagent sulfuric acid were dissolved in 1000 g of ion-exchanged water, respectively, and a 0.01 mol / l barium solution and 0.01 mol / l were dissolved.
l of sulfuric acid solution. Next, a sulfuric acid solution was charged into a 2 liter flask, and stirred at 200 rpm with a Teflon paddle.
After heating to ℃, the barium solution heated to 80 ℃ was added dropwise over 15 minutes. Then, after continuing stirring for 3 minutes, the reaction was terminated. The pH during the reaction was between 1.6 and 1.6. Next, the mixture was cooled to room temperature, filtered through 5C filter paper, washed with ion-exchanged water, and dried at 105 ° C. for 3 hours to obtain 2.2 g of barium sulfate powder. The powder thus obtained is an undeveloped fine-grained crystal having an average particle diameter of 0.5 μm and a crystal structure, a light scattering intensity of 28.1% and a total light transmittance of 89.2.
Further, when it was blended into a foundation, which is a cosmetic, the powder was fine and had a poor feeling in use, was poor in extensibility, and was inferior in light scattering.

[0022]

According to the present invention, the average particle size is from 4 to 20.
Barium sulfate having a physical property of coarseness of μm, light scattering intensity of 50% or more, and total light transmittance of 70% or more can be stably produced. Such a powder has excellent usability and concealment, It is useful as an extender for cosmetics having high light scattering and transparency.

Continuation of Front Page (72) Inventor Ichiro Sakamoto 1130 Nishihama, Nishihama, Wakayama City, Wakayama Pref. ) Surveyed field (Int.Cl. ⁶ , DB name) C01F 11/46 A61K 7/02

Claims (3)

(57) [Claims] 1. A method for producing barium sulfate, comprising reacting a baurim compound with a sulfate compound under the following conditions (a) to (c). (A) a 0.001-0.1 mol / l barium compound solution and a sulfate compound solution are reacted at a molar ratio of the barium compound to the sulfate compound of 0.1 to 5; (b) the barium compound solution and the sulfate compound solution The dropping time for adding either one to the other is 2 seconds to 7 minutes. (C) The pH of the reaction system is 0.5 to 10. 2. The barium compound is one or more selected from barium hydroxide, barium chloride, barium nitrate and barium acetate, and the sulfate compound is one selected from sulfuric acid, sodium sulfate, sodium hydrogen sulfate and ammonium sulfate. 2. The method according to claim 1, wherein the method is at least two kinds. 3. The process according to claim 1, wherein the reaction is carried out by adding barium hydroxide and / or barium chloride to sulfuric acid.