JP2000219819A - Fine particulate titanium dioxide composition, its production and cosmetic compounded with the fine particulate titanium dioxide composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fine particulate titanium dioxide composition wettable with water and having excellent water dispersibility, ultraviolet shielding power, discoloration resistance and production workability. SOLUTION: The objective fine particulate titanium dioxide composition is produced by using a fine titanium dioxide particle having maximum particle diameter of <=0.1 μm and an average primary particle diameter of 0.01-0.08 μm as a core particle, coating the surface of the core particle with an inner layer consisting of 8-15 wt.% of a high-density silicon oxide in terms of SiO2 based on the fine titanium dioxide particle, coating the product with an intermediate layer consisting of 5-10 wt.% of hydrated aluminum oxide in terms of Al2O3 based on the fine titanium dioxide particle and finally coating the surface with an outer layer consisting of 2-7 wt.% of alginic acid based on the fine titanium dioxide particle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a fine particle dioxide which has good compatibility with water, is excellent in water dispersibility, ultraviolet shielding ability and discoloration resistance, and has excellent workability during production (filterability during production). The present invention relates to a titanium composition, a method for producing the titanium composition, and a cosmetic containing the fine titanium dioxide composition.

[0002]

2. Description of the Related Art Fine particle titanium dioxide having a maximum particle size of 0.1 μm or less is highly safe for the human body, has excellent transparency in the visible part, and has an ultraviolet shielding ability. It is used in a wide range of fields, such as paints, chemical fibers, etc. This fine particle titanium dioxide has a maximum particle diameter controlled to 0.1 μm or less so as to be suitable for exhibiting its properties, and because the primary particle diameter is small, it is easy to aggregate when dispersed in a medium, To resolve this, strong dispersion energy is required.

[0003] The nature of the above-mentioned fine particles of titanium dioxide, which tend to agglomerate in a medium and cannot be sufficiently dispersed in the medium, is a serious problem for the cosmetics industry. Studies have been carried out, but nothing has yet been found. In particular, the demand for water-based cosmetics has increased in recent years, as there has been a great demand for cosmetics that emphasize the texture, such as low stickiness and smoothness. There is a need for fine particulate titanium dioxide.

[0004]

The fine particle titanium dioxide itself and the fine particle titanium dioxide composition whose surface is coated with an inorganic compound in order to improve the weather resistance and the like are inherently hydrophilic. Easy to aggregate in the medium,
There is a problem that it cannot be sufficiently dispersed in a medium.

[0005] For this reason, surface treatment with metal soap or silicone has been proposed. However, when the surface treatment is performed with these, the particle surface of the fine titanium dioxide composition becomes water repellent. Therefore, it is a high-quality, fine-particle titanium dioxide-based compound that can be blended with water-based cosmetics and has excellent water dispersibility, ultraviolet shielding ability, discoloration resistance, workability during production (filterability during production), etc. Is required.

The present invention has been made in view of the above-mentioned circumstances, and provides a fine particle titanium dioxide composition which is well-adapted to water, and has excellent water dispersibility, ultraviolet shielding ability, discoloration resistance and workability during production. The purpose is to:

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, coated a specific amount of high-density silicon oxide as an inner layer on the surface of the core fine particle titanium dioxide. By coating a specific amount of hydrated oxide of aluminum as an intermediate layer on it and coating a specific amount of alginic acid on it as an outer layer, it has good compatibility with water, water dispersibility, UV shielding ability, discoloration resistance A fine particle titanium dioxide composition having excellent properties and workability during production (filterability during production) was successfully produced. Also, by blending the fine particle titanium dioxide composition in cosmetics,
It has also been found that a cosmetic having high transparency and excellent ultraviolet shielding ability can be obtained.

That is, the first gist of the present invention is that
The maximum primary particle diameter is 0.1 μm or less and the average primary particle diameter
Is 0.01 to 0.08 μm.
On the surface, as the inner layer, S
iO_Two8-15% high density silicon oxide coating
And Al as the intermediate layer based on the weight of the fine particle titanium dioxide.
_TwoO_Three5-10% aluminum hydrated oxide
Coated, as an outer layer 2 parts by weight of fine titanium dioxide
Fine particle titanium dioxide composition coated with ~ 7% alginic acid
Things.

A second aspect of the present invention is a method for producing the above-mentioned fine particle titanium dioxide composition through the following first to third steps.

[First Step] An aqueous suspension of fine particle titanium dioxide having a maximum particle diameter of 0.1 μm or less and an average primary particle diameter of 0.01 to 0.08 μm is heated to 80 ° C. or more to form a base. To adjust the pH to 9 or higher.
To the aqueous suspension, 8 to 15% of a silicate compound as SiO _{2 based on} the weight of the fine particle titanium dioxide is added, and then the suspension is neutralized by adding an acid at a constant rate.

[Second step] After neutralization, 5-10% of a water-soluble aluminum salt is added as Al ₂ O ₃ to the weight of the fine titanium dioxide, and then the pH of the system is adjusted to 3-6. Mature.

[Third step] After aging, 2-8% of a water-soluble alginate as alginic acid is added to the weight of the fine titanium dioxide particles, and the mixture is aged for 1 hour or more.

Further, a third aspect of the present invention is a cosmetic comprising the above-mentioned fine particle titanium dioxide composition in a ratio of 1 to 80% by weight based on the whole.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the fine titanium dioxide composition of the present invention will be described.

The fine particle titanium dioxide composition of the present invention is characterized in that the maximum particle diameter is 0.1 μm or less and the average primary particle diameter is 0.01 to 0.08 μm. A specific amount of silicon oxide, followed by a specific amount of a hydrated oxide of aluminum as an intermediate layer, and then a specific amount of alginic acid as an outer layer to constitute a fine particle titanium dioxide composition.
In the above order, on the surface of the core fine particle titanium dioxide,
By coating silicon oxide, aluminum hydrated oxide, and alginic acid with high density, the fine particle titanium oxide composition can have excellent water dispersibility, ultraviolet shielding ability, discoloration resistance, and workability. The high-density silicon oxide refers to a state as described in US Pat. No. 2,885,366. That is, it means that the silicon oxide is amorphous, has a high degree of polymerization, and is in a dense state.

[0016] The order of coating affects the properties of the resulting particulate titanium dioxide composition. For example, if the coating of high-density silicon oxide is not performed first, but after the coating of aluminum hydrated oxide or alginic acid, the water dispersibility and discoloration resistance of the resulting fine-grained titanium dioxide composition are significantly affected. However, the filter cake becomes thixotropic in the filtration step and the washing step during production, and the workability is greatly reduced, and the ultraviolet shielding ability of the obtained fine particle titanium dioxide composition is reduced.
In addition, when the order of the coating of the aluminum hydrated oxide and the coating of the alginic acid is changed, the water dispersibility and ultraviolet shielding ability of the obtained fine particle titanium dioxide composition are significantly reduced.

The role of each coating layer on the fine particle titanium dioxide is such that the high density silicon oxide as the inner layer is based on the improvement of the discoloration resistance and the water dispersibility of the fine particle titanium dioxide, and the improvement of the water dispersibility. It is considered that the property of improving the ultraviolet shielding ability is imparted. It is considered that the hydrated oxide of aluminum as the intermediate layer plays a role in further improving discoloration resistance and fixing alginic acid to be coated as the outer layer. The alginic acid as the outer layer is considered to provide the obtained fine particle titanium dioxide composition with properties such as improved water dispersibility, ultraviolet shielding ability, and workability (filterability).

It should be noted that the water dispersibility can be improved by coating the outer layer of the fine particle titanium dioxide composition with a polysaccharide such as hyaluronic acid, carrageenan or pectin or carboxymethylcellulose instead of alginic acid. According to the study, the fine particle titanium dioxide composition coated with alginic acid had the best properties.

Next, the method for producing the fine particle titanium dioxide composition of the present invention will be described in detail.

The fine particle titanium dioxide composition of the present invention is produced by subjecting the surface of the fine particle titanium dioxide to a specific three-step coating treatment.

The fine particle titanium dioxide used in the production of the fine particle titanium dioxide composition, when powdered, has a maximum particle diameter of 0.1 μm or less and an average primary particle diameter of 0.01 to 0.08 μm. Refers to titanium dioxide.
The shape of the particles may be spherical, rod-like, or needle-like, but if it is not spherical, it is preferable that the length of the major axis is within the above-mentioned range of the particle diameter. In the case of performing the coating treatment, the above-mentioned fine titanium dioxide powder may be suspended in water to form an aqueous suspension, but preferably, an aqueous suspension of the fine titanium dioxide is used as a titanyl sulfate solution or a titanium tetrachloride solution. It is preferable to use an acidic titania sol or an acidic titania sol having a rutile-type crystal structure obtained by hydrolyzing and peptizing hydrochloric acid as an aqueous suspension of the fine particle titanium dioxide composition.

In the first step, a silicate compound is added to the aqueous suspension of the above-mentioned fine particle titanium dioxide, and the surface of the fine particle titanium dioxide is coated with silicon oxide as an inner layer at a high density. At this time, the silicate compound used as the silica source is not particularly limited, for example, sodium silicate, alkali silicates such as potassium silicate, etc., various types can be used, particularly sodium silicate preferable.

The condition for densely coating silicon oxide on the particle surface of the fine particle titanium dioxide, that is, for coating the silicon oxide with high density, is as follows.
It is preferable to heat to 0 ° C. or higher and adjust the pH to 9.0 or higher using caustic soda or aqueous ammonia. Also, at the time of neutralization after the addition of the silicate compound, it is preferable to add the acid at a constant rate, and at that time, neutralize for a certain time or more. If the rate of neutralization with an acid is increased, high-density silicon oxide is less likely to be formed. If silicon oxide having low density (low density silica) is coated on the surface of titanium oxide fine particles, the particles tend to agglomerate, and desired water dispersibility cannot be obtained.

The coating amount of silicon oxide is preferably 8 to 8% as SiO _{2 with} respect to the weight of the core fine particle titanium dioxide.
It is 15%, preferably 10 to 13%. If the coating amount of silicon oxide is less than the above range, discoloration resistance, water dispersibility is not sufficiently improved, and if the coating amount of silicon oxide is more than the above range, the content of fine particle titanium oxide is small. As a result, the ultraviolet shielding ability peculiar to the fine particle titanium oxide is impaired.

In the second step, a hydrated oxide of aluminum is coated on the high-density silicon oxide coated as an inner layer on the surface of the fine particle titanium dioxide. As the aluminum compound used in the coating treatment, a water-soluble aluminum salt is suitably used, and specific examples thereof include sodium aluminate, aluminum sulfate, and polyaluminum chloride.

The coating amount of the aluminum hydrated oxide is based on the weight of the core fine titanium dioxide, Al ₂ O ₃
5 to 10%, preferably 6 to 9%. When the coating amount of the aluminum hydrated oxide is less than the above range, the discoloration resistance may be insufficient, or the alginic acid coated as the outer layer may not adhere well. When the coating amount of the aluminum hydrated oxide is larger than the above range, the particles are firmly adhered to each other during drying and are hard to be crushed, which may cause a reduction in dispersibility and ultraviolet shielding ability. is there.

After the addition of the aluminum compound, the pH is adjusted to 3-6. When the pH is lower than 3, the alginic acid is aggregated and fixed, the water dispersibility is not sufficiently improved, the ultraviolet shielding ability is not sufficiently improved, and when the pH is higher than 6,
There is a possibility that the solubility of the alginate becomes too high and the alginate cannot be sufficiently fixed to the hydrated oxide of aluminum. When a neutralizing agent is required for the above pH adjustment, the neutralizing agent used is preferably ammonia water, caustic soda or the like as a base, and hydrochloric acid or sulfuric acid as an acid.

In the third step, as described above, high-density silicon oxide is formed as an inner layer on the surface of the fine titanium dioxide particles,
Then, after the aluminum hydrated oxide is coated, alginic acid is coated on the aluminum hydrated oxide.
In the above-mentioned alginic acid coating treatment, a water-soluble alginic acid salt is used as the alginic acid source, and specific examples thereof include, for example, sodium alginate and potassium alginate.

The molecular weight of the water-soluble alginate used is:
20 to 500 are preferable, and 50 to 300 are more preferable.
It is. When the molecular weight of the water-soluble alginate is smaller than the above range, dispersion stability and suspension retention may be reduced. Further, when the molecular weight of the water-soluble alginate is larger than the above range, the adhesion between particles becomes strong, and large energy is required for crushing, and as a result, dispersibility,
There is a possibility that the ultraviolet shielding ability may be reduced.

The coating amount of alginic acid is 2 to 7%, preferably 3 to 6%, based on the weight of the core fine particle titanium dioxide. If the alginic acid coverage is less than the above range, satisfactory workability cannot be obtained. Further, when the coating amount of alginic acid is larger than the above range, adhesion between particles becomes strong, and large energy is required for crushing, and as a result, dispersibility, ultraviolet shielding ability, etc. may be reduced as a result. .

After the addition of the water-soluble alginate, the mixture is aged for 1 hour or more. It takes ripening time to dissolve all the water-soluble alginate in the system and fix it as alginic acid on the surface of the fine particle titanium dioxide composition. If the aging time is less than 1 hour, the water-soluble alginate is completely dissolved. And the surface coating ends incompletely. This aging time may be long, but in consideration of productivity, usually up to about 3 hours is suitable.

The fine particle titanium dioxide composition obtained through the above-mentioned three steps, in which the fine particle titanium dioxide is the core and the surface of which is sequentially coated with high-density silicon oxide, aluminum hydrated oxide, and alginic acid, is The mixture is filtered and washed by a known method, and further repulped (to remove the above-mentioned cake, the fine particle titanium dioxide concentration is reduced to 70%) for the purpose of removing the electrolyte component contained in the cake which is the solid content after the filtration.
g / l), followed by washing with water. At this time, the pH is adjusted so that the pH of the product becomes neutral. General methods are applied to the drying and pulverizing operations. As a pulverizer used for the pulverizing operation, an Ech atomizer, a fluid energy mill, or the like can be used, but a fluid energy mill having a high pulverizing strength is preferable in order to improve water dispersibility and ultraviolet shielding ability as much as possible.

The fine particle titanium dioxide composition produced by the above method was boiled in water and then filtered. As a result, almost no water-soluble alginate or alginic acid was found in the filtrate. Since the improvement in hydrophilicity of the fine-particle titanium dioxide composition itself has been confirmed as compared to before the coating with alginic acid, it can be said that the alginic acid is firmly fixed on the particle surface by the above-mentioned coating treatment. It is estimated to be.

Further, before performing the coating treatment with silicon oxide of high density, the surface of the fine particle titanium oxide as a core is treated with a metal other than the above, for example, a metal other than the above, as long as the properties intended in the present invention are not impaired. It may be covered with an oxide or a hydroxide of zirconium, titanium, zinc, iron, cerium, or the like.

By blending the fine particle titanium dioxide composition of the present invention as an active ingredient, a cosmetic having high transparency and excellent ultraviolet shielding ability can be obtained, and in particular, an excellent sunscreen cosmetic can be obtained. . The compounding amount when the above-mentioned fine particle titanium dioxide composition is compounded in cosmetics is 1
Although it can be used in a wide range of up to 80% by weight, for example, in a powder formulation such as a powder foundation, 40
About 80% by weight, and about 1 to 40% by weight for emulsifiers such as liquid foundations and creams. These cosmetics are produced in the same manner as in the conventional art except that the above-mentioned fine particle titanium dioxide composition is blended, and can be used for the same applications as in the conventional art. In addition to the above-mentioned fine particle titanium dioxide composition, other inorganic and organic ultraviolet absorbers or surfactants may be further added to this cosmetic.

[0036]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples. In the following examples,% indicating the concentration of a solution or dispersion is% by weight unless otherwise specified.

Example 1 An aqueous solution of a titanyl sulfate crystal manufactured by Teica was heated to form
Hydrolyzate is filtered and washed to obtain hydrous titanium oxide.
35 kg cake (titanium oxide content: TiO _TwoIn conversion
10%), 48% aqueous sodium hydroxide solution 4
Add 0kg with stirring and heat to 95-105 ° C
For 2 hours. Then this titanium dioxide water
The suspension of the hydrate was filtered and the cake was thoroughly washed. Washing
50 kg of water is added to the subsequent cake to form a slurry,
Add 14kg of 35% hydrochloric acid while stirring, and at 95 ℃
Heat aging for 2 hours. The solid particles in this slurry are X-ray
Diffraction showed the crystal structure of rutile titanium dioxide. Get
The aqueous suspension of the finely divided particulate titanium dioxide is 70 g / l.
The concentration was adjusted as follows. This particulate titanium dioxide
The maximum particle size is 0.07 μm and the average primary particle size is
It was 0.015 μm.

20 liters of the aqueous suspension of fine particle titanium dioxide obtained as described above (1400 in terms of TiO ₂₎
g) After being weighed, coating treatment was performed in the following steps.

[First Step] The aqueous suspension of the fine particle titanium dioxide was adjusted to pH 9.0 or more using caustic soda,
840 ml of 200 g / l aqueous sodium silicate solution
(12% as SiO ₂ with respect to the fine particle titanium dioxide), and the mixture was heated to 80 ° C and neutralized with sulfuric acid over 150 minutes to adjust the pH to 6.5.

[Second Step] 1120 g of polyaluminum chloride was added to the aqueous suspension (A for fine titanium dioxide).
After the addition, the mixture was neutralized using caustic soda to a pH of 5.0 and aged for 30 minutes.

[Third Step] After aging, 77.7 g of sodium alginate (5% as alginic acid with respect to fine titanium dioxide) was added to the above aqueous suspension, and after aging for 1 hour, the pH was adjusted to 5.0. Adjusted and aged for another 30 minutes.

After passing through the above steps, filtration and washing were performed, and repulp, water washing, filtration and washing were performed again. The obtained filter cake was dried and pulverized with a fluid energy mill to obtain a fine particle titanium dioxide composition.

Example 2 The addition amount of the aqueous sodium silicate solution in the first step was 700
ml (10 as SiO ₂ for fine titanium dioxide)
%), Except that the treatment was performed in the same manner as in Example 1.

Example 3 The amount of the aqueous sodium silicate solution added in the first step was 980.
ml (14 as SiO ₂ for fine titanium dioxide)
%), Except that the same process was performed as in Example 1.

Example 4 The addition amount of polyaluminum chloride in the second step was 84
0 g (6 as Al ₂ O _{3 with} respect to fine particle titanium dioxide)
%), Except that the treatment was performed in the same manner as in Example 1.

Example 5 The addition amount of polyaluminum chloride in the second step was 12
The same treatment as in Example 1 was performed, except that the amount was increased to 60 g (9% as Al ₂ O _{3 with} respect to the fine particle titanium dioxide).

Example 6 The amount of sodium alginate added in the third step was 4
The same treatment as in Example 1 was performed except that the amount was reduced to 6.7 g (3% as alginic acid with respect to the fine particle titanium dioxide).

Example 7 The amount of sodium alginate added in the third step was 9
The same treatment as in Example 1 was performed, except that the amount was increased to 3.3 g (6% as alginic acid with respect to the fine particle titanium dioxide).

Comparative Example 1 The same treatment as in Example 1 was performed except that the addition of the aqueous sodium silicate solution in the first step was omitted.

Comparative Example 2 The amount of the aqueous sodium silicate solution added in the first step was 350
ml (5% as SiO ₂ with respect to fine particle titanium dioxide)
The same processing as in Example 1 was performed except that the number was reduced to.

Comparative Example 3 The amount of the aqueous sodium silicate solution added in the first step was 140
0ml (20 as SiO ₂ for fine titanium dioxide)
%), Except that the same process was performed as in Example 1.

Comparative Example 4 The same treatment as in Example 1 was performed except that the second step was omitted and the addition of polyaluminum chloride was not performed.

Comparative Example 5 The amount of polyaluminum chloride added in the second step was 42
0 g ( ₃ as Al ₂ O _{3 with} respect to fine particle titanium dioxide)
%), Except that the treatment was performed in the same manner as in Example 1.

Comparative Example 6 The amount of polyaluminum chloride added in the second step was 16
The same processing as in Example 1 was performed except that the amount was increased to 80 g (12% as Al ₂ O _{3 with} respect to the fine particle titanium dioxide).

Comparative Example 7 The same treatment as in Example 1 was performed, except that the addition of sodium alginate in the third step was omitted.

Comparative Example 8 The amount of sodium alginate added in the third step was 1
The same treatment as in Example 1 was performed except that the amount was reduced to 5.6 g (1% as alginic acid with respect to the fine particle titanium dioxide).

Comparative Example 9 The amount of sodium alginate added in the third step was 15
The same treatment as in Example 1 was performed, except that the amount was increased to 5.6 g (10% as alginic acid with respect to the fine particle titanium dioxide).

Comparative Example 10 The same processing as in Example 1 was performed except that the processing order of the first step and the second step was reversed.

Comparative Example 11 The same processing as in Example 1 was performed except that the processing order of the second step and the third step was reversed.

Comparative Example 12 The same processing as in Example 1 was performed, except that the processing order of the first step and the third step was reversed.

Comparative Example 13 After treating the first step in the same manner as in Example 1, the second and third steps were omitted, and filtration, washing and drying were performed as they were.

Comparative Example 14 As the core titanium dioxide, an average primary particle diameter of 0.0
The same treatment as in Example 1 was performed, except that pigment-grade rutile type titanium dioxide having an average primary particle diameter of 0.28 μm (trade name: JR, manufactured by Teica) was used instead of the 15 μm fine particle titanium dioxide.

Comparative Example 15 The same aqueous suspension of 70 g / l of fine particle titanium dioxide as in Example 1 was added to 20 liters (1400 in terms of TiO _2).
g) Weigh it and use ammonia water to adjust the pH to 7.
5 and aged for 30 minutes, filtered by a known method,
After washing, 14 g of sodium hexametaphosphate (TiO 2
₍ 1% in terms of ₂ ) After mixing, the mixture was pulverized. This sodium hexametaphosphate is blended in accordance with the prior art to improve the water dispersibility of the fine particle titanium dioxide.

The samples obtained in Examples 1 to 7 and Comparative Examples 1 to 14 were evaluated by the following methods. The evaluation results are shown in Tables 3 and 4. Tables 1 and 2 show the coating configuration of each sample.

[Workability (thixotropy)] About 4 liters of the aqueous suspension after the surface treatment step (first to third steps) is completed.
About 280 g in terms of TiO ₂ ) is completely filtered by suction filtration using a Nutsche having a diameter of 240 mm to prepare a titanium oxide hydrated cake. When the Nutsche containing the titanium oxide hydrated cake was shaken, it was visually determined whether or not the hydrated cake had fluidity, and the results were symbolized in the following criteria and shown in Tables 3 and 4.

〇: Does not have fluidity. That is, the workability is good. X: Fluid. In other words, thixotropy occurs and workability is poor

[Water dispersibility] The water dispersibility is evaluated by the suspension retention. That is, a mixture of 15 g of the titanium dioxide composition obtained in each of Examples and Comparative Examples and 135 g of pure water was mixed,
The obtained mixture is put into a 300 ml beaker. Disperse using a homogenizer at 3000 rpm for 10 minutes. Transfer this dispersion to a 100 ml graduated cylinder
l Weigh in. After standing for 24 hours, the state of the dispersion was observed, and the volume of the suspended layer was measured. The results are shown in Tables 3 and 4. The larger the volume of the suspension layer, the better the suspension retention and the better the water dispersibility.

[Discoloration resistance] The titanium dioxide compositions obtained in each of the examples and comparative examples were each replaced with a titanium dioxide composition /
Finsolv TN with 1% Vitamin E (C12-1
5 Alkyly Benzoate, Finetex
Inc. Mix) at a mixing ratio of 3/4 for 3 minutes. The obtained mixture is placed on a white board, a cover glass is placed thereon, and the color tone L, a, b of each sample is measured with a colorimeter (CR-200 manufactured by Minolta). Titanium dioxide not coated as blank / Finsolv
L0, a0, and b0 are measured by performing the same operation as described above for a mixture of TN solution = 3/4. Then, the degree of discoloration (ΔE) of each sample was determined by the following equation, and the results are shown in Tables 3 and 4. The smaller the ΔE value is, the better the discoloration resistance is.

ΔE = [(L−L ₀ ) ² + (a−a ₀ ) ² +
(bb ₀ ) ² ] ^1/2 L, a, b: color tone after sample L ₀ , a ₀ , b ₀ : blank color tone

[Ultraviolet Shielding Ability with Water Slurry] 15 g of the titanium dioxide composition obtained in each of Examples and Comparative Examples and pure water 1
35 g and the resulting mixture is charged into a 300 ml beaker. 3000 rpm using a homogenizer
Disperse for 10 minutes. A part of the obtained dispersion was sampled, and this was treated with water to obtain a titanium dioxide content of 0.1%.
Dilute to 0005% (2000-fold). 1 dilution
Using a cm quartz cell, the transmittance at a wavelength of 300 nm was measured (U-3300 manufactured by HITACHI).
The results are shown in Tables 3 and 4. The smaller the transmittance value, the better the ultraviolet shielding ability.

[Ultraviolet Shielding Ability in Cosmetic] A sunscreen is prepared as a cosmetic with the following composition, and the ultraviolet shielding ability is evaluated.

Sunscreen cream formulation: [Water phase] Titanium dioxide composition 10.0 g Butylene glycol 8.0 g Triethanolamine 1.0 g Pure water 69.8 g KS-66 (antifoaming agent) 0.05 g [Oil phase] Stearic acid 1.8 g Cetyl alcohol 1.4 g Squalane 6.0 g Surfactant Leodol super SP-L10 1.0 g Surfactant Leodol super TW-L120 1.0 g

The water phase and the oil phase weighed in the above formulation are each heated to 80 ° C. Disperse the titanium dioxide composition blended in the aqueous phase using a homogenizer (300
10 minutes at 0 rpm). The oil phase is added to the aqueous phase over about 30 seconds. After addition, emulsify using a homomixer (4
000 rpm for 30 seconds). After emulsification, cool to room temperature with ice water.

Each of the obtained sunscreen creams was applied on a polypropylene film (thickness: 40 μm) so as to have a thickness of 12 μm, and a spectrophotometer (available from Hitachi, Ltd.)
3300) is used to measure the transmittance at a wavelength of 300 nm,
The results are shown in Tables 3 and 4. The lower the transmittance value, the better the ultraviolet shielding ability.

[Transparency] 10 parts of the above sunscreen cream
It was applied to the skin of the upper arm of the name paneler, and each paneler was visually evaluated for the transparency, and the evaluation results are shown in Table 2 as symbols according to the following criteria.

〇: When 7 or more panelists evaluated that there was transparency ×: When 6 or less panelists evaluated that there was transparency

Tables 3 and 4 show the evaluation results of the above workability, water dispersibility, discoloration resistance, ultraviolet ray shielding ability with water slurry, ultraviolet ray shielding ability with cosmetics, and transparency. Tables 1 and 2 show the coating configurations of the samples. Table 1
In Table 2 and Table 2, "high-density silicon oxide" is abbreviated as "high-density Si", and "hydrated oxide of aluminum" is abbreviated as "Al hydroxide". In Tables 1 and 2, “↑” means “same as above”.
In Comparative Example 14, rutile-type pigment-grade titanium dioxide having an average primary particle diameter of 0.28 μm was used as the core (all other rutile-type pigments having an average primary particle diameter of 0.015 μm were used as the core. In Comparative Example 15, rutile-type fine particle titanium dioxide was blended with 1% (based on TiO ₂ ) of sodium hexametaphosphate.

[0078]

[Table 1]

[0079]

[Table 2]

Tables 3 and 4 show the evaluation of workability, water dispersibility, discoloration resistance, ultraviolet shielding ability with water slurry, ultraviolet shielding ability with cosmetics, and transparency as described above. The results are shown. The numerical values shown in Tables 3 and 4 with respect to the ultraviolet ray shielding ability of the water slurry and the ultraviolet ray shielding ability of the cosmetic are the transmittance (%) of ultraviolet rays having a wavelength of 300 nm.

[0081]

[Table 3]

[0082]

[Table 4]

Table 3 showing the characteristics of Examples 1 to 7 and Comparative Example 1
As is clear from comparison with Table 4 showing the characteristics of
Examples 1 to 7 are all excellent in workability, large in the volume of the suspension layer, excellent in water dispersibility, small in ΔE value, excellent in discoloration resistance, small in transmittance of ultraviolet rays, and blocked in ultraviolet rays. It was excellent in performance and had a transparent feeling.

[0084]

As described above, the fine particle titanium dioxide composition of the present invention is excellent in water dispersibility, ultraviolet shielding ability, discoloration resistance, and workability during production (filterability during production).

Further, by blending the above-mentioned fine particle titanium dioxide composition, a cosmetic having high transparency and excellent ultraviolet shielding ability can be provided.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C09C 3/08 C09C 3/08 F term (reference) 4C083 AB171 AB172 AB221 AB222 AB241 AB242 AC022 AC072 AC122 AC242 AC442 AC542 AD152 AD301 AD302 BB26 CC05 CC19 DD31 EE01 EE07 EE17 FF01 4J037 AA22 CA09 CA12 CA15 CA25 CC02 DD05 EE04 EE25 EE28 EE43 EE46 EE47 FF02 FF30

Claims (3)

[Claims] 1. A fine particle titanium dioxide having a maximum particle diameter of 0.1 μm or less and an average primary particle diameter of 0.01 to 0.08 μm as a core, and an inner layer is formed on the surface thereof as SiO based on the weight of the fine particle titanium dioxide. ₂ as to cover 8-15% of the density of the silicon oxide, the weight of the fine particulate titanium dioxide to coat the hydrated oxide of 5-10% of aluminum as for Al ₂ O ₃ intermediate layer, fine particles dioxide as the outer layer A fine-grain titanium dioxide composition coated with 2-7% of alginic acid based on the weight of titanium. 2. A method for producing a particulate titanium dioxide composition, comprising producing the particulate titanium dioxide composition according to claim 1 through the following first to third steps. [First step] An aqueous suspension of fine particle titanium dioxide having a maximum particle size of 0.1 µm or less and an average primary particle size of 0.01 to 0.08 µm is heated to 80 ° C or more, and a base is added. The pH is adjusted to 9 or more, and after the pH adjustment, a silicate compound of 8 to 15% as SiO _{2 with} respect to the weight of the fine particle titanium dioxide is added to the aqueous suspension, and then the acid is added to the suspension. At a constant rate to neutralize. After Second Step] neutralization, after adjusting the addition of 5-10% of the water-soluble aluminum salt as Al ₂ O ₃ relative to the weight of particulate titanium dioxide, then the pH of the system to 3-6 and aged. [Third Step] After aging, 2-8% of a water-soluble alginate as alginic acid is added to the weight of the fine titanium dioxide particles, and the mixture is aged for 1 hour or more. 3. A cosmetic comprising the fine particle titanium dioxide composition according to claim 1 in a ratio of 1 to 80% by weight based on the whole. [0001]