JP2931180B2 - Method for producing iron-containing ultrafine titanium dioxide - 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 ultrafine titanium dioxide containing iron, a sunscreen cosmetic using the same, and an ultraviolet ray preventing paint.

[0002]

2. Description of the Related Art Ultrafine titanium dioxide having a primary particle size of about 0.1 .mu.m or less, when incorporated into a resin film or molded product, transmits visible light so that it exhibits transparency. It is well known that it exhibits properties different from those of pigment-grade titanium dioxide having a primary particle size of 0.15 to 0.5 μm, for example, to protect substances that undergo discoloration or alteration due to the following conditions. For this reason, utilization as a sunscreen cosmetic for making use of natural skin color and preventing sunburn due to ultraviolet rays has recently attracted particular attention. However,
Conventionally, commercially available ultrafine titanium dioxide has a strong cohesive force, and it is difficult to completely disperse the primary particles in an aqueous or oily medium.For example, a sunscreen cosmetic containing ultrafine titanium dioxide is used. When applied to the skin, it often has the disadvantage of causing strong scattering of bluish shades, giving bluish tones and, thus, making the skin look unhealthy. Further, the conventional ultrafine titanium dioxide sufficiently shields the light beam having the wavelength in the ultraviolet B region (wavelength 320 to 290 nm), but the light beam having the wavelength in the ultraviolet A region (wavelength 380 to 320 n).
m) is insufficiently shielded, and in recent years, skin damage due to ultraviolet rays in the A region has become a problem. For this reason, it is a fact that organic ultraviolet absorbers and the like are used in combination.

As a sunscreen cosmetic which has an excellent ultraviolet shielding effect and does not impart a bluish color, for example, a cosmetic composition comprising fine particle titanium oxide and fine particle iron oxide (Japanese Patent Laid-Open No. Sho 62-62).
No. 67014) has been proposed. However, simply blending titanium dioxide and iron oxide in this manner causes color separation in the cosmetic due to the difference in dispersibility between the two, and insufficient shielding of light having a wavelength in the ultraviolet A region. There are problems. Recently, several methods have been proposed to make titanium dioxide and iron oxide into a single pigment in order to prevent the color separation. For example, titanium dioxide particles having an average particle diameter of 0.01 to 1 μm are treated with iron oxide hydroxide or the like, and dried or fired (Japanese Patent Publication No. 4-50).
No. 01), a basic higher fatty acid iron salt is applied to titanium dioxide having a maximum particle size of 0.1 μm (JP-A-61-26463).
No. 2), the surface of titanium dioxide particles having a maximum particle size of 0.1 μm or less is treated with an oxide or hydroxide of aluminum, silicon or iron (Japanese Patent Application Laid-Open No. 2-204326). However, these are all methods using titanium dioxide fine particles, treating the surface with an iron hydroxide or oxide, and drying or baking. In these methods, the so-called blueness reduction and ultraviolet A region shielding effect are achieved. Is not enough. Also, a titanium oxide / iron oxide composite sol having a Fe ₂ O ₃ / TiO ₂ (weight ratio) of 0.05 to 50 (Japanese Patent Laid-Open No. 2-178219) has been proposed. This is intended to improve the shielding ability in the ultraviolet A region, which is insufficient with titanium sol, but because it is in the form of a sol, its formulation into cosmetics and paints is limited, and durability and long-term stability There is still a problem in terms of.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an ultraviolet light
An object of the present invention is to obtain ultrafine iron-containing titanium dioxide which is greatly improved in the shielding ability of an area and which does not give a bluish hue and which is most suitable for sunscreen cosmetics or anti-ultraviolet paints.

[0005]

Means for Solving the Problems The inventors of the present invention have developed an ultraviolet A
Various investigations were conducted to obtain ultrafine titanium dioxide which has an excellent region shielding ability and does not give a bluish color tone. as a result,
An acidic aqueous solution of a titanium salt and an acidic aqueous solution of an iron salt are simultaneously hydrolyzed in the presence of an alkali substance, and thereafter, the hydrolysis product is calcined at 300 to 800 ° C., so that the average single particle diameter is 0.01%. It has been found that ultrafine iron-containing titanium dioxide having a blue-color tone scattering property of less than 0.1 μm and improved in both the shielding property in the ultraviolet A region and the light color of the powder color can be obtained. .

The iron-containing ultrafine titanium dioxide of the present invention thus obtained has an excellent ability to shield ultraviolet rays A, and has a very low bluish color tone even when a cosmetic or the like containing the same is applied to the skin. . That is, the present invention is a titanium dioxide having an average single particle diameter of 0.01 to 0.1 μm, and an iron-containing ultrafine particle titanium dioxide containing 1 to 30% by weight of TiO ₂ as an iron component with respect to TiO _2. . In the present invention, since an acidic aqueous solution of a titanium salt and an acidic aqueous solution of an iron salt are simultaneously hydrolyzed in the presence of an alkaline substance and then calcined, the obtained iron-containing ultrafine titanium dioxide has a strong titanium component and an iron component. The iron component is contained inside the crystal, or the reaction product of the iron component and the titanium component forms the main component,
Alternatively, a part of the iron component is contained as iron oxide, or even a part or all of them are contained, and even when blended in a cosmetic or paint under strong dispersion conditions,
Without color separation of iron component and titanium dioxide,
The shielding ability in the ultraviolet A region is remarkably improved, a bluish color tone is hardly exhibited, and further, a lighter powder color is brought about. The average particle diameter of the iron-containing ultrafine titanium dioxide of the present invention is 0.0 as an average single particle diameter by electron micrograph.
The thickness is 1 to 0.1 μm, preferably 0.02 to 0.08 μm. The amount of the iron component in the iron-containing ultrafine titanium dioxide is 1 to 30% by weight, preferably 2 to 20% by weight, based on titanium dioxide, in terms of Fe. If the amount of the iron component is too large, the coloring due to the iron content becomes too strong, and the heat resistance, chemical resistance and the like of titanium dioxide are impaired. On the other hand, if it is less than the above range, it becomes difficult to obtain sufficient blueness reduction ability, ultraviolet A region shielding ability, and the like.

[0007] The iron-containing ultrafine titanium dioxide of the present invention may contain a small amount of at least one metal element such as aluminum, zinc, sodium, potassium, magnesium, and phosphorus, if necessary. This makes it possible to control the particle size of the obtained iron-containing ultrafine titanium dioxide and to improve the durability. Furthermore, the ultrafine titanium dioxide of the present invention may be treated or coated with at least one inorganic compound of a metal oxide or hydroxide such as aluminum, silicon, titanium, zircon, tin, and antimony on the surface thereof. it can. Further, it may be treated or coated with at least one of various organic compounds used in the field of cosmetics and pigments, for example, carboxylic acids, polyols, amines, siloxanes, silane coupling agents and the like. The dispersibility in paints and paints and the durability of coating films can be further improved.

Next, a method for producing the iron-containing ultrafine titanium dioxide of the present invention will be described. As the acidic aqueous solution of titanium in the present invention, there are generally titanium sulfate, titanium chloride, etc. It is industrially advantageous. Examples of the acidic aqueous solution of the iron salt include aqueous solutions of ferrous chloride, ferrous sulfate, ferric chloride, ferric sulfate, ferric nitrate, and the like.

In the method of the present invention, simultaneous hydrolysis of an acidic aqueous solution of a titanium salt and an acidic aqueous solution of an iron salt can be carried out by various methods. For example, alkaline methods such as sodium hydroxide, sodium carbonate, and aqueous ammonia can be used. Aqueous solution of the substance at 40-90 ° C, preferably 60-80
C. and neutralization by adding an acidic aqueous solution of a titanium salt and an acidic aqueous solution of an iron salt in parallel, or by mixing and adding these acidic aqueous solutions in advance. In particular, a mixed acidic aqueous solution of a titanium salt and an iron salt previously prepared so as to be 1 to 30% by weight, preferably 5 to 20% by weight with respect to titanium dioxide in terms of Fe is neutralized. Is desirable. The neutralization reaction is preferably performed while adjusting the pH of the system to 8 to 10.

[0010] Next, the product obtained by the hydrolysis by neutralization is separated and washed, and then dried or calcined at a temperature of 300 to 850 ° C without drying.
Ultrafine iron-containing titanium dioxide of 1 to 0.1 μm is used.
Thereafter, pulverization is performed using a wet pulverizer such as a sand mill, a pebble mill, and a disk mill, or a dry pulverizer such as a fluid energy mill, a hammer mill, and an edge runner mill.

In the method of the present invention, a hydrated oxide of a metal such as aluminum, silicon, titanium, zirconium, tin or antimony is precipitated and coated on the surface of the iron-containing ultrafine titanium dioxide particles obtained by the above method. Is also good. In this method, for example, the iron-containing titanium dioxide obtained by calcining and pulverizing is dispersed in water to form a slurry, and if necessary, wet pulverizing and classifying, and then aluminum, silicon, titanium, zirconium, tin And at least one selected from the group of water-soluble salts of antimony is added to titanium dioxide in an amount of 1 to 30% by weight in terms of oxide, and if the water-soluble salt shows alkalinity in the slurry, sulfuric acid, hydrochloric acid If the water-soluble salt is acidic in the slurry, the solution is neutralized with an alkaline solution such as sodium hydroxide or aqueous ammonia to precipitate and coat the surface of the titanium dioxide particles, and this is separated. Thereafter, drying and pulverization can be performed. By this coating treatment, the dispersibility, durability and the like of the iron-containing ultrafine titanium dioxide dispersion medium can be improved.

When a plurality of metal hydrates are coated in the treatment with the inorganic compound, the hydrates of various metals may be precipitated simultaneously or sequentially.

The ultrafine iron-containing titanium dioxide of the present invention is useful for various sunscreen cosmetics and UV protection paints as described above. It is suitable. When the ultrafine iron-containing titanium dioxide of the present invention has a diffraction peak at 2θ = 24.5 ° (CuKα) in addition to the diffraction peak of the rutile-type titanium dioxide crystal in X-ray diffraction, the powder color becomes pale. It tends to be more suitable for use in cosmetics and other application systems.

[0014]

【Example】

Example 1 as TiO ₂ of 200 g / l concentration of the four mixed acid was added to tetrahydrate aqueous solution of ferrous chloride in titanium chloride aqueous solution containing 7.0 wt% of iron as Fe with respect to the TiO ₂ An aqueous solution was prepared. The mixed acidic aqueous solution 1 was added to 2500 g of a 20% by weight aqueous sodium carbonate solution heated to 70 ° C.
800 g was added over 30 minutes, and then an aqueous sodium hydroxide solution was added over 40 minutes to adjust the pH to 9, and titanium tetrachloride and ferrous chloride were hydrolyzed to form a precipitate. Was. The obtained hydrolysis product was then aged for 60 minutes, filtered and washed. The obtained washed cake is 600
C. for 3 hours, dispersed in water, and wet-pulverized with a sand mill to obtain a slurry of ultrafine titanium dioxide. The slurry was heated to 70 ° C. and then stirred with TiO ₂
A 2.0% by weight aqueous solution of aluminum sulfate as Al ₂ O ₃ was added thereto over 30 minutes, followed by addition of a sodium hydroxide solution to adjust the pH to 7.0, thereby precipitating hydrated alumina. Coated. Thereafter, the mixture was aged for 60 minutes, filtered, washed, dried, and then pulverized with a fluid energy mill to obtain an average single particle size of 0.0
4 μm ultrafine titanium dioxide (A) was obtained.

Example 2 Ultrafine titanium dioxide (B) was obtained in the same manner as in Example 1 except that the composition of the mixed acidic aqueous solution was changed to 10.0% by weight as Fe with respect to TiO ₂ . X-ray diffraction analysis of the ultrafine titanium dioxide (B) confirmed that a clear peak appeared at 2θ = 24.5 ° in addition to the rutile crystal peak.

Comparative Example 1 Ultrafine titanium dioxide (C) was obtained in the same manner as in Example 1 except that an aqueous ferrous chloride solution was not added.

Comparative Example 2 Comparative Example 2 was repeated except that a 2.0% by weight aqueous solution of aluminum sulfate was added as Al ₂ O ₃ in 30 minutes instead of adding a 7% by weight aqueous solution of ferrous sulfate as Fe. 1
In the same manner as in the above, ultrafine titanium dioxide (D) was obtained.

Comparative Example 3 The ultrafine titanium dioxide (D) of Comparative Example 2 was calcined at 600 ° C. for 3 hours and pulverized by a fluid energy mill to obtain ultrafine titanium dioxide (E).

Comparative Example 4 Commercially available ultrafine iron oxide (particle diameter: about 0.04 μm) was mixed with the ultrafine titanium dioxide (C) of Comparative Example 1 so as to be 7% by weight as Fe and mixed powder ( F) was obtained.

Comparative Example 5 Commercially available iron oxide for pigment (particle size: about 0.2 μm) was used in Comparative Example 1.
Was mixed so as to be 7% by weight as Fe with respect to the ultrafine titanium dioxide (C) to obtain a mixed powder (G).

[0021]

[Test example]

Test Example 1 A sample (2 g) was prepared, an aluminum ring (inner diameter: 33 mm, height: 5 mm) was placed on a SUS plate, and the sample was piled on the aluminum ring. This was sandwiched between SUS plates at the top and bottom, and pressed by a press machine at 200 kg / cm ² × 10 seconds for molding.
The powder color (L, a, b) of this molded product was measured with a color difference meter. The results are shown in Table 1.

[0022]

[Table 1]

Test Example 2 Ultrafine titanium dioxide particles (A) to (G) were used as sunscreen creams according to the following formulations. (1) 2.5 parts by weight of stearic acid (2) 3.5 parts by weight of beeswax (3) 3.5 parts by weight of cetanol (4) 17.0 parts by weight of squalane (5) 3.0 parts by weight of glycerin monostearate (6) Ultrafine titanium dioxide 3.0 parts by weight (7) Methyl paraben 0.1 parts by weight (8) Glycerin 12.0 parts by weight (9) Triethanolamine 1.0 parts by weight (10) Purified water 54.1 parts by weight Part (11) Perfume 0.3 parts by weight A mixture obtained by heating and mixing components (1) to (6) at 80 ° C. is added to a mixture obtained by heating and mixing components (7) to (10) at 80 ° C. Mix well and stir vigorously. 45 ° C
In the vicinity, (11) was added to prepare a sunscreen cream.

Evaluation Method 1 Each of the above creams was applied on quartz glass so as to have a thickness of 25 μm, and the transmittance at 750 to 300 nm was measured with a spectrophotometer.

Evaluation method 2 After each of the above creams was normally used by 10 women aged 20 to 52 years, the creams were visually evaluated with respect to each other. Table 2 shows the above evaluation results.

[0026]

[Table 2]

[0027]

The iron-containing ultrafine titanium dioxide obtained in the present invention has a strong binding between a titanium component and an iron component.
There is no color separation between iron component and titanium dioxide. When applied to sunscreen cosmetics, the ability to block ultraviolet rays A is significantly improved. When applied to cosmetics, even when applied to skin, strong scattering of blue tint is observed. It exhibits remarkably excellent effects such as making the skin look healthy without causing it, the powder color tends to be light-colored, and the formulation in the application system of cosmetics and the like can be more easily made. In addition, when applied to a wood coating for preventing ultraviolet rays, an excellent ultraviolet shielding effect and a favorable color tone can be imparted.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C01G 49/00 C01G 23/047

Claims (5)

(57) [Claims] 1. A after the acidic aqueous solution of an acidic aqueous solution and an iron salt of titanium salt is hydrolyzed in the presence of alkaline material, calcining the resulting precipitate, 1-30 weight relative TiO ₂ iron component as Fe %, And the average single particle diameter is 0.01 to
A method for producing iron-containing ultrafine titanium dioxide having a particle size of 0.1 μm. 2. The particle surface has aluminum, silicon,
The method for producing ultrafine iron-containing titanium dioxide according to claim 1, wherein the iron-containing ultrafine titanium dioxide is coated with a hydrated oxide or an oxide of at least one element selected from the group consisting of titanium, zirconium, tin and antimony. 3. The method for producing ultrafine iron-containing titanium dioxide according to claim 1, wherein the firing is performed at a temperature of 300 to 850 ° C. 4. A sunscreen cosmetic comprising the iron-containing ultrafine titanium dioxide obtained by the method according to claim 1, 2 or 3. 5. An ultraviolet protection coating containing the iron-containing ultrafine titanium dioxide obtained by the method according to claim 1.