JP5955137B2 - Method for producing spherical titanium dioxide - Google Patents

Description

The present invention relates to a method for producing spherical titanium dioxide.

  Titanium dioxide is one of highly safe coloring pigments that have excellent coloring power and concealability, are structurally stable, and are highly safe. On the other hand, when the particle diameter is 1 μm or less, an excellent ultraviolet blocking effect and the like are exhibited due to the effects of so-called volume effect and surface effect. For this reason, when imparting an ultraviolet blocking effect to cosmetics and the like blended in skin care and makeup, fine particle titanium dioxide is widely blended mainly as an ultraviolet blocking agent.

  However, cosmetics blended in skin care and makeup may deteriorate over time due to contact with sweat or sebum, and may cause unevenness due to insufficient adhesion of titanium dioxide itself to the skin. In some cases, the ultraviolet blocking effect is not always sufficient. Moreover, when the touch to skin was bad, or when the particle diameter was 100 nm or less, there was a problem of having a safety problem for the human body. As a method for solving these problems, a method of producing plate-like titanium dioxide (see Patent Document 1) and a method of containing an inorganic pigment in silica-based porous particles (see Patent Document 2) have been adopted. Either method can be expected to improve the UV protection effect and improve the feeling of use by reducing the blending amount of the protective agent, but there are still concerns about safety.

  In order to improve the touch, various production methods for obtaining spherical titanium dioxide have been proposed. For example, a method for obtaining a crystalline spherical titanium dioxide by dissolving a non-oxide raw material such as titanium carbide by heating with oxygen-containing plasma and simultaneously causing an oxidation reaction (see Patent Document 3), or an oxygen containing hydrogen peroxide. A method of obtaining spherical titanium dioxide by hydrothermally treating a titanium salt such as titanium sulfate at a temperature of 150 to 230 ° C. in an autoclave (see Patent Document 4), and further titanyl sulfate at a temperature of 170 ° C. or higher under pressure. A method of obtaining spherical anatase-type titanium dioxide by hydrolysis at a temperature of 400 to 900 ° C. after hydrolysis (see Patent Document 5) is known. However, although these production methods can synthesize spherical titanium dioxide, all of them are production methods that consume a large amount of energy, and a method for producing spherical titanium dioxide at a lower cost is required. In addition, in order to control the particle size of the spherical titanium dioxide, a method of controlling the particle size using the autoclave as described above has been actively studied. However, as described above, a large amount of energy is consumed during production. Therefore, provision of a method capable of controlling the particle diameter of spherical titanium dioxide by an environment-friendly reaction at a low temperature is demanded.

  Further, when titanium dioxide is used as a cosmetic, a rutile type having low catalytic activity is required. Rutile type titanium dioxide is known to have lower catalytic activity than anatase type, but in order to obtain rutile type titanium dioxide, it is usually necessary to heat to 900 ° C or higher, and very high energy is required. And Therefore, there is a demand for a method for producing rutile-type titanium dioxide in an environment-friendly manner as much as possible.

Japanese Patent Laid-Open No. 10-212211 JP 2005-53846 A JP 2002-274851 A JP 2000-191325 A Japanese Patent Laid-Open No. 05-163022

The present invention has been made in view of such problems, and can be controlled to a particle size of 100 nm or more by a production method based on an environmentally friendly soft solution reaction, and has a uniform spherical shape, and its crystal structure is rutile. It is an object of the present invention to provide a method for producing spherical titanium dioxide which is a mold and exhibits a sufficient ultraviolet blocking effect.

As a result of intensive studies, the present inventors have added an acidic solution such as hydrochloric acid or nitric acid to a titanium salt solution, and heated from 60 ° C. to 95 ° C. while adjusting the rate of temperature rise, thereby performing a soft solution reaction. A spherical particle in which fine primary particles are accumulated and synthesized can be obtained, and the obtained spherical particle is fired under a temperature condition of 800 ° C. or less to achieve the above-mentioned object. The present inventors have found that titanium can be obtained and have completed the present invention.
The spherical titanium dioxide thus obtained has a primary particle size of 100 mm or less when the primary particles are measured by an X-ray diffraction method, and the apparent average particle size of the spherical titanium dioxide particles of the aggregate is 100 nm or more. Furthermore, the average axial ratio is 0.8 or more.

In short, the method for producing spherical titanium dioxide according to the present invention is as follows.
An acidic solution is added to a 0.5 to 5.0% titanium salt solution in terms of Ti and synthesized by a soft solution reaction at 60 ° C. to 95 ° C. , and the particles are controlled to be spherical by the soft solution reaction. The particle diameter is uniformly controlled, and then the rutile-type spherical titanium dioxide is obtained by firing at 800 ° C. or lower.

In the first invention, the rate of temperature increase during the soft solution reaction is preferably 0.2 ° C./min to 0.6 ° C./min ( second invention).

According to the present invention, the titanium salt solution is diluted with water and adjusted to 0.5 to 5.0% by mass in terms of Ti, then an acidic solution such as hydrochloric acid or nitric acid is added, and then 60 ° C to 95 ° C. The synthesis proceeds by soft solution reaction, and the hydrolysis proceeds and titanium dioxide is precipitated. The resulting particles are spherical titanium dioxide having a uniform particle size. By firing the particles, the crystal structure is rutile. Become a mold. The spherical titanium dioxide thus obtained has an apparent average particle diameter of 100 nm or more and an average axial ratio of 0.8 nm as an aggregate composed of primary particles having an average particle diameter of 100 mm or less as measured by an X- ray diffraction method. That's it. That is, it is possible to produce spherical titanium dioxide having a particle diameter of 100 nm or more, a uniform spherical shape, uniform particle diameters, and a crystal structure that is a rutile type, and having reduced catalytic activity.

Photograph (a) observed with transmission electron microscope of spherical titanium dioxide obtained in Production Example 1 and photograph (b) observed with scanning electron microscope The graph which shows the X-ray-diffraction result of the spherical titanium dioxide obtained in manufacture example 1

Next, specific embodiments of the method for producing spherical titanium dioxide according to the present invention will be described.

  The apparent particle diameter of the spherical titanium dioxide of the present invention is 100 nm or more, and fine primary particles are accumulated to form spherical titanium dioxide. Here, the particle diameter of the accumulated spherical particles can be controlled by the reaction conditions. Further, the apparent average particle diameter of the spherical titanium dioxide of the present invention is measured by observing with a transmission electron microscope (TEM), measuring the diameter of any 20 primary particles, and calculating the average value. can do.

  The spherical titanium dioxide of the present invention is produced as follows. That is, the titanium salt solution is diluted with water and diluted to 0.5% to 5.0% in terms of Ti. An acidic solution such as hydrochloric acid is added to the solution and stirred. Thereafter, the temperature is increased from 60 ° C. to 95 ° C. at 0.2 ° C./min to 0.6 ° C./min, and the synthesis is performed by a soft solution reaction. Thereafter, neutralization is performed with an alkali solution such as sodium hydroxide, followed by washing with water, filtration and drying to obtain spherical titanium dioxide. During the heating reaction, stirring may be performed to obtain the target particle size.

As the titanium salt solution, titanium trichloride, titanium tetrachloride, titanium sulfate and the like can be used, and it is particularly preferable to use titanium tetrachloride.
Examples of the acidic solution include hydrochloric acid, nitric acid, sulfuric acid and the like, and hydrochloric acid is particularly preferable. When hydrochloric acid is added, for example, Ti is preferably added so that Cl is in a range of 3 mol / L to 5 mol / L with respect to 1 mol / L, more preferably, Ti is 1 mol / L. , Cl is in the range of 3.5 mol / L to 4 mol / L.
The reaction temperature in the reaction is preferably 60 ° C to 95 ° C, but the best condition is 70 ° C.

  Thereafter, the spherical titanium dioxide obtained by the above method is fired, and the firing condition is preferably in the temperature range of 300 ° C to 800 ° C. More preferably, it is the range of 400 degreeC-600 degreeC. As a result of analysis by X-ray diffraction even when the firing temperature is less than 300 ° C., the rutile-type crystal structure of titanium dioxide can be confirmed, but the orientation of the crystal is improved by firing at 400 ° C. or higher. As a result, defects such as oxygen defects in the crystal are reduced. Moreover, also about the ultraviolet-ray shielding effect, an ultraviolet-ray can be shielded from the long wavelength side wavelength. On the other hand, when the firing temperature is higher than 800 ° C., the treatment is performed at a high temperature, the load on the environment is increased, and the shape of titanium dioxide is sintered and the spherical shape cannot be maintained.

Next, the hydrophobic spherical titanium dioxide according to the present invention will be described.
In the present invention, when spherical titanium dioxide is used as a foundation or sunscreen agent, it is necessary to impart hydrophobicity to these powders since water resistance is required after application to the skin. In order to impart hydrophobicity to the powder, the surface of the powder is coated with a compound such as polysiloxane, an alkylsilane compound, an alkyl titanate compound, or a fluorine compound. In addition to the above compounds, various conventionally known surface treatments can be applied. A plurality of these processes can be combined.

  Specific examples of the surface coating organic compound include methyl hydrogen polysiloxane, dimethyl polysiloxane, and acrylic silicone copolymer as silicone compounds, and n-octyltriethoxysilane as alkyl titanate as alkyl silane. Isopropyl triisostearoyl titanate, and fluorine-based compounds such as perfluoroalkyl phosphate ester and perfluoroalkylethoxysilane.

  Further, as a treatment method for coating the surface of the hydrophobic compound, the pigment to be coated is stirred in a suitable mixer, the compound to be coated with the surface is added under a droplet or by spray spraying, and then stirred at high speed for a certain time. . Then, the method of performing the reaction surface coating process by making it heat-ripen at 80-200 degreeC, continuing stirring is common. Alternatively, the surface coating compound is dissolved in alcohols such as ethanol, isopropyl alcohol and isobutanol, hydrocarbon organic solvents such as toluene, n-hexane and cyclohexane, polar organic solvents such as acetone, ethyl acetate and butyl acetate. In addition, after adding and stirring the cosmetic pigment to the solution while stirring, the organic solvent is completely removed by evaporation, and then the surface coating treatment is performed by heating and aging at 80 to 200 ° C. It is done.

  As the mixing and dispersing method, an appropriate method can be selected according to the concentration and viscosity of the solution. Preferable examples include a method using a mixer such as a disper, a Henschel mixer, a Redige mixer, a kneader, a V-type mixer, a roll mill, a bead mill, or a biaxial kneader, or a water solution by spraying an aqueous solution and a pigment into heated air. It is possible to select a spray drying method or the like that removes at a stroke. When pulverization is performed, a normal pulverizer such as a hammer mill, a ball mill, a sand mill, or a jet mill can be used. Since any of these pulverizers can obtain the same quality, it is not particularly limited.

  In this case, the mass ratio of the component which is a compound used for the pigment surface coating treatment is 0.5 to 30% by mass with respect to the pigment to be coated. If the mass ratio is less than 0.5% by mass, the long lasting effect and the uniform adhesion to the skin are not sufficient, and if it exceeds 30% by mass, the feel becomes very oily and moisturized. Not suitable as a fee.

  In addition, the form of the cosmetic to which the surface-coated spherical titanium dioxide (spherical powder) of the present invention is blended is not particularly limited. , Mouth refresher, mouth odor prevention agent, gargle, toothpaste, bathing agent, antiperspirant, soap, shampoo, rinse, body soap, body lotion, deodorant agent, hair cream agent, whitening agent, skin cleanser, hair restorer, etc. Can be mentioned.

  In addition, in cosmetics formulated with the spherical powder of the present invention, in addition to the spherical powder, oils, powders (pigments, pigments, resins), fluorine compounds, resins, surfactants used in ordinary cosmetics Components such as an agent, a sticking agent, a preservative, a fragrance, a humectant, a physiologically active ingredient, a salt, a solvent, a chelating agent, a neutralizing agent, and a pH adjusting agent can be blended at the same time. Here, as the powder, for example, red 104, red 201, yellow 4, blue 1, black 401 and other dyes, yellow 4 aluminum lake, yellow 203 barium lake and other lake dyes, Nylon powder, silk powder, urethane powder, Teflon powder (Teflon: registered trademark), silicon powder, cellulose powder, polymers such as silicon elastomer, yellow iron oxide, red iron oxide, black iron oxide, chromium oxide, carbon black, ultramarine , Colored pigments such as bitumen, white pigments such as titanium oxide and cerium oxide, extender pigments such as talc, mica, sericite and kaolin, pearl pigments such as mica titanium, barium sulfate, calcium carbonate, magnesium carbonate, aluminum silicate, Metal salts such as magnesium silicate, inorganic powders such as silica and boron nitride, Particles of titanium oxide, fine particles of iron oxide, alumina-treated fine titanium oxide particles, silica treated ultrafine titanium dioxide, bentonite, smectite, and the like. There are no particular restrictions on the shape and size of these powders. These powders may or may not be subjected to various conventionally known surface treatments. Examples of surface treatments include, for example, acrylic silicon treatment, methyl hydrogen polysiloxane treatment, silicone resin treatment, octyltriethoxysilane treatment, N-acylated lysine treatment, organic titanate treatment, silica treatment, alumina treatment, cellulose treatment, par Various hydrophilic, lipophilic, and water-repellent treatments such as fluoropolyether treatment and fluorinated silicone resin treatment can be used. Examples of the oil include higher alcohols such as cetyl alcohol, isostearyl alcohol, lauryl alcohol, hexadecyl alcohol, octyldodecanol, fatty acids such as isostearic acid, undecylenic acid, oleic acid, glycerin, sorbitol, ethylene glycol, propylene glycol, Polyhydric alcohols such as polyethylene glycol, myristic myristate, hexyl laurate, decyl oleate, isopropyl myristate, hexyl decyl dimethyloctanoate, glyceryl monostearate, diethyl phthalate, ethylene glycol monostearate, octyl oxystearate, etc. Esters, hydrocarbons such as liquid paraffin, petrolatum, squalane, lanolin, reduced lanolin, wax such as carnauba wax, mink , Cacao oil, coconut oil, balm kernel oil, camellia oil, sesame oil, castor oil, oils such as olive, ethylene-alpha-olefin co-oligomer, and the like. In addition, methyl hydrogen polysiloxane, dimethyl polysiloxane, methyl phenyl polysiloxane, polyether-modified organopolysiloxane, fluoroalkyl / polyoxyalkylene co-modified organopolysiloxane, alkyl-modified organopolysiloxane, fluorine-modified organopolysiloxane, amodimethicone , Silicon compounds such as amino-modified organopolysiloxane, silicon gel, acrylic silicon, trimethylsiloxysilicic acid, silicon RTV rubber, and fluorine compounds such as perfluoropolyether, fluorinated pitch, fluorocarbon, fluoroalcohol, and fluorinated silicone resin It is done. Examples of the surfactant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, and a betaine surfactant. Examples of the solvent include purified water, ethanol, light liquid isoparaffin, lower alcohol, ethers, LPG, fluorocarbon, N-methylpyrrolidone, fluoroalcohol, perfluoropolyether, alternative chlorofluorocarbon, and volatile silicon.

Next, specific examples of the method for producing spherical titanium dioxide according to the present invention will be described with reference to the drawings. Hereinafter, an example in which spherical titanium dioxide is prepared is referred to as a “manufacturing example”, and an example in which a cosmetic is prepared using the spherical titanium dioxide powder is simply referred to as an “example”. In addition, this invention is not limited to the Example described below.

(Production Example 1)
Titanium tetrachloride having a Ti concentration of 16.5% (Cl = 31%) was used. 460 parts by mass of water was added to 40 parts by mass of titanium tetrachloride with 16.5% Ti. Further, 40 parts by mass of 18.2% hydrochloric acid was added to the solution and stirred. Then, it heated up to 70 degreeC on the temperature increase rate of 0.28 degree-C / min condition, and reacted for 3 hours after reaching 70 degreeC. Thereafter, neutralization, washing with water, filtration and drying were performed to obtain spherical titanium dioxide having an average particle size of 200 nm. The obtained spherical titanium dioxide was fired at 600 ° C. for 3 hours to obtain rutile-type spherical titanium dioxide.

  The photograph which observed the spherical titanium dioxide obtained by manufacture example 1 with the transmission electron microscope (TEM) and the scanning electron microscope (SEM) is each shown by Fig.1 (a) (b). As shown in FIG. 1, the average particle diameter of the obtained spherical titanium dioxide was about 200 nm. Further, from the graph showing the crystal structure by X-ray diffraction shown in FIG. 2, the crystal structure of the obtained spherical titanium dioxide particles was rutile type.

(Production Example 2)
Titanium tetrachloride having a Ti concentration of 16.5% (Cl = 31%) was used. 450 parts by mass of water was added to 50 parts by mass of titanium tetrachloride with 16.5% Ti. Further, 50 parts by mass of 18.2% hydrochloric acid was added to the solution and stirred. Then, it heated up to 70 degreeC on the temperature increase rate of 0.28 degree-C / min condition, and reacted for 3 hours after reaching 70 degreeC. Thereafter, neutralization, washing with water, filtration and drying were performed to obtain spherical titanium dioxide having an average particle size of 400 nm. The obtained spherical titanium dioxide was fired at 600 ° C. for 3 hours to obtain rutile-type spherical titanium dioxide.

(Production Example 3)
The spherical titanium dioxide obtained in Production Example 1 was subjected to a surface coating treatment with methyl hydrogen polysiloxane.
In a Henschel mixer, 1000 parts by mass of the spherical titanium dioxide obtained in Production Example 1 was added, and then a solution in which 20.4 parts by mass of methylhydrogenpolysiloxane was dissolved in 125 parts by mass of isopropyl alcohol was added dropwise and mixed. Mix well with titanium. Thereafter, the interior of the Henschel mixer was heated and depressurized to remove isopropyl alcohol. The treated powder was taken out from the Henschel mixer, pulverized and heat-treated to obtain spherical titanium dioxide treated with 2% by mass of silicon compound.

The surface-treated spherical titanium dioxide obtained in Production Example 3 was mixed with silicone oil (SF8417 manufactured by Toray Dow Corning Co., Ltd.) so as to be 20% by mass, and 100 rpm, 3 times with Hoover Marler. And dispersed. A transpore tape was applied on a 5 cm × 8 cm quartz plate, and 0.08 g of the dispersion dispersed by the above method was uniformly applied on the tape. After standing for 15 minutes, the Sun Protecion Factor (SPF) and ProtecTion grade of UVA (PA) were measured using an SPF analyzer (UV-1000S manufactured by Labsphere). As a comparative product, a commercially available titanium dioxide having a primary particle diameter of 200 nm and a specific surface area of 10 m ² / g was similarly surface-treated by the above silicon treatment method. The results are shown in Table 1. As shown in Table 1, when the surface-treated spherical titanium dioxide obtained in the present invention was compared with a commercially available silicon-treated product (comparative product) from the measurement results of SPF and PA, a high ultraviolet shielding effect was obtained. I found out.

Example 1
[Manufacture of sunscreen agents]
A sunscreen agent was prepared according to the formulation shown in Table 2 and the following production method. In addition, the unit of the compounding quantity in a table | surface is mass%.

Production method:
Components A and B are mixed at 80 ° C., and after confirming that they are uniformly dispersed, they are cooled to 30 ° C. After cooling, component B was added to component A little by little with stirring with a homomixer and mixed well until uniform to obtain a spherical titanium dioxide-containing sunscreen.

(Comparative Example 1)
A product was obtained in the same manner as in Example 1 except that commercially available titanium dioxide treated with silicon was used instead of the silicon-treated spherical titanium dioxide produced in Production Example 3.

  About the cosmetics produced in Example 1 and Comparative Example 1, the sensory evaluation test regarding a usability | use_condition was implemented by 10 female panelists. The test was conducted in a questionnaire format, and each item was scored between 0 and 5 points, 0 points were badly evaluated, 5 points were evaluated as excellent, and the result was expressed as the average score of all panelists. . Therefore, the higher the score, the better the evaluation. The evaluation results are shown in Table 3.

表３の結果より、実施例１は比較例１よりも、使用感、化粧持ち、肌の透明感全てにおいて優れる結果となっていることが分かる。

From the results in Table 3, it can be seen that Example 1 is superior to Comparative Example 1 in terms of usability, longevity, and skin transparency.

According to the present invention, it is possible to provide spherical titanium dioxide having a rutile-type crystal structure with low catalytic activity and an average particle diameter of 100 nm or more, and a hydrophobic compound is provided on the surface of the spherical titanium dioxide. Since coated powder can be blended, it is possible to provide cosmetics with excellent use feeling, transparency, and long-lasting makeup when applied to the skin, such as foundations, eye shadows, cheeks, lipsticks, etc. It is suitable for use in makeup cosmetics or sunscreen cosmetics and has great industrial applicability.

Claims (2)

An acidic solution is added to a 0.5 to 5.0% titanium salt solution in terms of Ti and synthesized by a soft solution reaction at 60 ° C. to 95 ° C. , and the particles are controlled to be spherical by the soft solution reaction. A method for producing spherical titanium dioxide, characterized in that rutile-type spherical titanium dioxide is obtained by uniformly controlling the particle diameter and then performing firing at 800 ° C. or lower. The method for producing spherical titanium dioxide according to claim 1 , wherein the temperature rising rate during the soft solution reaction is 0.2 ° C / min to 0.6 ° C / min.

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