JPH11171753A - Cosmetic containing coated fine-particle titanium dioxide composition as active ingredient - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cosmetic containing as active ingredient fine-particle titanium dioxide highly compatible with oily phase and having high dispersibility and light resistance. SOLUTION: This cosmetic is obtained by formulating 1-80 wt.%, based on the whole cosmetic, of fine-particle titanium dioxide which is produced through an outline of the following process: a specific amount of a water-soluble aluminum compound is added to an aqueous suspension of titanium dioxide with a particle size of <=0.1 μm followed by setting the resultant slurry at a specified pH value with a neutralizing agent; the slurry is then heated to >=80 deg.C and incorporated with a specific amount of a >=7C fatty acid or a water- soluble salt thereof; subsequently, the slurry pH is adjusted to a specified level followed by aging the slurry for >=30 min; finally, the pH is adjusted again, followed by performing filtration, washing, drying, and grinding operations. This cosmetic has excellent anti-suntan effect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cosmetic composition containing a fine titanium dioxide coating composition having good dispersibility and light resistance as an active ingredient and having good compatibility with an oil phase.

[0002]

2. Description of the Related Art Fine titanium dioxide particles having a particle diameter of 0.1 μm or less have excellent ultraviolet shielding ability and are therefore used in cosmetics such as sunscreens. However, cosmetics using the finely divided titanium dioxide powder as they are have the drawbacks that they are not easily compatible with the oil phase and that the cosmetics are easily discolored by light.

Some measures have been reported as measures against the above problem. For example, Japanese Patent Publication No. 3-39017 discloses a method of producing a titanium oxide having a hydrophobic surface by reacting a fatty acid and a water-soluble polyvalent metal salt in a dispersion of titania sol. Also, Japanese Patent Publication No. 56-34
No. 232 discloses a method of making a solid surface lipophilic by utilizing a coprecipitation reaction between a basic polyaluminum salt and a fatty acid.

[0004]

However, in these treatment methods, when titanium dioxide is incorporated into cosmetics, there are cases where a dispersion having insufficient hydrophobicity and poor compatibility with an oil phase is obtained. In addition, the compounded cosmetics tended to be easily discolored by light. The present invention provides a cosmetic containing fine titanium dioxide particles having good compatibility with an oil phase and having excellent dispersibility and light resistance.

[0005]

Means for Solving the Problems In order to improve the lack of hydrophobicity and light resistance of a sunscreen cosmetic containing fine particle titanium dioxide coated with a fatty acid polyvalent metal salt, the present inventors conducted various studies. went. As a result, the coating treatment was first performed using a water-soluble aluminum salt, and then the fine particle titanium oxide obtained by performing the coating treatment using a fatty acid having 7 or more carbon atoms or a water-soluble salt thereof was added to the cosmetic. Was found to eliminate the disadvantages.

That is, the present invention is a cosmetic containing the titanium dioxide coating composition obtained through the following steps (1) to (3) as an active ingredient. (1) After adding 8 to 15% by weight (based on titanium dioxide) of a water-soluble aluminum compound as Al ₂ O ₃ to an aqueous suspension of titanium dioxide having a particle size of 0.1 μm or less,
The pH of the system is adjusted to 5-8 using an acid or base neutralizer. (2) The temperature of the system is raised to 80 ° C. or higher by heating, and a fatty acid having 7 or more carbon atoms or a water-soluble salt thereof is added to the system at 10 to 20% by weight (based on titanium dioxide) in terms of fatty acid.
Then, the pH of the system is adjusted to 7 to 7 using an acid or base neutralizing agent.
9 and aged for 30 minutes or more in this state. (3) After aging, the pH of the system is adjusted to 6.5 to 7.5, and then filtration, washing, drying, and pulverizing operations are performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The titanium dioxide coating composition of the present invention differs from the prior art in that a titanium dioxide surface is coated with a hydrated aluminum oxide using a water-soluble aluminum salt. The treatment is performed, and thereafter, a coating treatment is performed by adding a fatty acid having 7 or more carbon atoms or a water-soluble salt thereof. By treating in this order, the hydrophobicity and light resistance of the titanium dioxide coating composition are improved, and an excellent sunscreen cosmetic is obtained.
Regarding the above-mentioned coating treatment sequence on titanium dioxide to be blended in the cosmetic, the hydrating oxide of aluminum and the fatty acid or its water-soluble salt are simultaneously coated, or the aluminum is added after adding the fatty acid or its water-soluble salt. When the hydrated oxide is coated, the dispersibility, light resistance and hydrophobicity of the powder are not improved, and consequently, cosmetics containing the same do not exhibit excellent properties.

The method for producing the titanium dioxide coating composition to be blended in the present invention will be described in detail according to the above steps. Step (1): As an aqueous suspension of titanium dioxide having a particle diameter of 0.1 μm or less, a titania sol having rutile-type crystal structure of titanium dioxide obtained by hydrolyzing a titanyl sulfate solution, a titanium tetrachloride solution, or the like. It is good to use. The titanium dioxide particles in the titania sol are substantially dispersed as primary particles, and various surface treatments can be performed on the individual particles. In order to produce a titania sol in which titanium dioxide has a rutile-type crystal structure as described above, for example, it can be obtained by treating a hydrolyzed cake with a caustic alkali and aging by heating in hydrochloric acid.

Regarding the hydrated aluminum oxide coated on the surface of the titanium dioxide particles, sodium aluminate, aluminum sulfate and the like are preferable as the water-soluble aluminum salt as a raw material. The amount of aluminum salt, 8 to 15 wt% as Al ₂ O ₃ of titanium dioxide based, preferably from about 10 to 12%. If the processing amount of Al ₂ O ₃ is less than 8%, light resistance becomes insufficient. If the processing amount of Al ₂ O ₃ exceeds 15%, the particles are firmly fixed to each other during drying, requiring large energy for crushing and insufficient dispersibility.

After the addition of the aluminum salt, the pH is adjusted to 5 to 8 with a neutralizing agent to coat the surface of the titanium dioxide particles with hydrated aluminum oxide. As the neutralizing agent used, ammonia water, caustic soda and the like are preferable as the base, and hydrochloric acid and sulfuric acid are preferable as the acid. When coating with hydrated aluminum oxide, if necessary, inorganic oxides (including hydrates) other than aluminum oxide may coexist to such an extent that the properties aimed at by the present invention such as light resistance are not impaired. Good. As a substance, an oxide or hydrated oxide of silicon, zirconium, titanium, zinc, iron, cerium, or the like can be used. Further, two or more of these may be combined.

Step (2): The temperature of the slurry is raised to 80 ° C. or higher by heating, because the fatty acid or the water-soluble salt thereof having 7 or more carbon atoms to be added and the hydrated oxidation formed in the step (1) are added. This is for efficiently reacting with a substance. Fatty acids or water-soluble salts thereof to be added include fatty acids having 7 or more carbon atoms such as capric acid, lauric acid, myristic acid, stearic acid, coconut oil fatty acid, tallow fatty acid, oleic acid, linoleic acid, and linolenic acid. Higher fatty acids are preferred from the viewpoint of imparting hydrophobicity, and as the water-soluble salts of fatty acids, salts of the above fatty acids with alkali metals, ammonia, organic amines and the like can be used. When a fatty acid having a small number of carbon atoms is used, the resulting fatty acid salt becomes hydrophilic, so that the affinity with the oil phase is reduced.

When the amount of the fatty acid or the water-soluble salt thereof is 10
%, The obtained powder has insufficient hydrophobicity and pulverizability. On the other hand, if it exceeds 20%, the viscosity of the dispersed slurry is greatly increased, so that stirring becomes difficult and the productivity is reduced. After the addition of the fatty acid or its water-soluble salt,
The pH of the system is adjusted to 7 to 9 using an acid or base neutralizer, and the system is aged for 30 minutes or more. In this case, if the pH at the time of aging is lower than 7, fatty acids and hydrated aluminum oxide are used. And the amount of unreacted fatty acids increases. As a result, the fatty acid aggregates increase in the titanium oxide aqueous suspension, and the hydrophobicity of the obtained powder decreases. Also pH
Is more than 9, it is not preferable because the hydrated aluminum oxide dissolves.

Step (3): After aging, the aqueous suspension is adjusted to pH 6.5 to 7.5 using the neutralizing agent mentioned in Step (1), and then subjected to a solid-liquid separation operation. But in this case filtration,
For the washing, drying, and pulverizing operations, general known methods can be applied. In this step, it is preferable to carry out the operation while setting the pH as close to neutral as possible, since the surface treatment is finally stabilized. As a pulverizer used for the pulverizing operation, an Eku atomizer, a fluid energy mill, or the like can be used. The powder after pulverization has a very soft feel as compared with a sample to which sodium stearate is not added.

When the fine particle titanium oxide coating composition obtained in the above step was boiled in benzene and then filtered, no fatty acid was found in the filtrate. When the finely divided titanium oxide after filtration and drying was put into water and stirred, the hydrophobicity was not lost. from these things,
The added fatty acid is not released from the particle surface, and it is presumed that the fatty acid molecule is strongly attached to the aluminum atom and exists on the particle surface.

The cosmetic composition of the present invention contains the titanium dioxide coating composition thus obtained, and the compounding amount is 1 to 80% by weight, which is appropriately selected depending on the dosage form of the cosmetic composition. it can. That is, 40 to 80% by weight in a powder dosage form such as a powder foundation, 1 to 20% by weight in an oily dosage form such as a lipstick or an oily foundation,
For emulsifiers such as emulsified foundations and creams, the amount is preferably about 1 to 40% by weight. These cosmetics are manufactured by a conventional method and provided for each purpose.

The cosmetic of the present invention may contain a surfactant such as a sorbitan fatty acid ester, a polyglycerin fatty acid ester, a sucrose fatty acid ester, or a polyoxyethylene alkyl ether, a liquid paraffin, or the like as long as the effects of the present invention are not impaired. Hydrocarbons such as paraffin wax,
Fatty acid esters such as isopropyl palmitate and butyl stearate, silicone oils such as dimethicone and cyclomethicone, oils such as beeswax, olive oil and safflower oil, glycerin, propylene glycol, 1,3
-Polyhydric alcohols such as butylene glycol, stabilizers such as sodium chloride and magnesium sulfate, vitamins,
Pharmaceutical agents such as glycyrrhizinate, PABAs such as para-dimethylaminobenzoic acid, cinnamic acids such as octyl methoxycinnamate, benzophenones such as oxybenzone, and other UV absorbers such as salicylic acids, preservatives, and clothing Known components such as fragrances may be appropriately blended to give cosmetics such as foundations, lipsticks, lip balms, oily foundations, emulsions and creams, and especially cosmetics intended for sunscreen.

[0017]

Next, the present invention will be described in more detail by way of examples. However, the present invention is not limited only by those examples.

[0018]

Example 1 Step (1): A hydrolyzate produced by heating an aqueous solution of titanyl sulfate crystal manufactured by Teica Co., Ltd. was filtered and washed to obtain a hydrous titanium oxide cake, 35 kg (content of titanium oxide: TiO _2). Equivalent to 10 kg), 48
A 40% aqueous solution of sodium hydroxide was added thereto with stirring, and the mixture was heated and stirred at 95 to 105 ° C for 2 hours. Next, the suspension of the titanium dioxide hydrate was filtered, and the cake was sufficiently washed. Water, 5 on cake after washing
Add 0 kg to make a slurry, and further add 35% hydrochloric acid, 14
The mixture was added while stirring, and the mixture was heated and aged at 95 ° C. for 2 hours. The solid particles in this slurry showed a crystal structure of rutile titanium dioxide by X-ray diffraction. The concentration of the obtained titanium oxide aqueous suspension was adjusted to 70 g / l.
20 liters of the aqueous suspension obtained above (TiO ₂
(Converted to 1.4 kg) and 250 g / l in terms of Al ₂ O _3.
560 ml of an aqueous sodium aluminate solution (10% by weight in terms of Al ₂ O _{3 based on} titanium dioxide) was added thereto with stirring. Add sodium hydroxide aqueous solution
The H value was adjusted to 6.0 and aged for 30 minutes.

Step (2): After heating the aqueous suspension to 85 ° C., 238 g of sodium stearate (15.8% by weight in terms of fatty acid relative to titanium dioxide) was added. At this time, the pH value gradually increased and reached pH 7.0 after 10 minutes.
The slurry was aged for 1 hour.

Step (3): After aging, the pH value of the slurry is adjusted to 7.5 by adding an aqueous solution of sodium hydroxide or hydrochloric acid, and then aging for another 30 minutes. Dry at 15 ° C. for 15 hours. The dried product was pulverized with an Ek atomizer.

[0021]

Prior to the addition of sodium aluminate solution EXAMPLE 2 Step (1), first sodium silicate solution of 200 g / l in terms of SiO _2, 105 ml (1.5 wt% in terms of SiO ₂ with respect to titanium dioxide) After the addition, the same treatment as in Example 1 was performed except that 560 ml of a sodium aluminate solution was added.

[0022]

Example 3 The amount of sodium stearate added in step (2) was 168 g (1% in terms of fatty acid with respect to titanium dioxide).
1.2% by weight), and the same treatment as in Example 2 was carried out except that the pulverization of the dried product in the step (3) was performed using a fluid energy mill.

[0023]

Comparative Example 1 The same treatment as in Example 1 was carried out except that the amount of the aqueous sodium aluminate solution added in step (1) was 392 ml (7% by weight in terms of Al ₂ O _{3 based on} titanium dioxide).

[0024]

Comparative Example 2 The same treatment as in Example 1 was performed except that the operation after the addition of sodium stearate in Step 1 was changed as follows. First, 20 liters (1.4 kg in terms of TiO ₂ ) of the slurry obtained in the above step was heated to 85 ° C., and then 140 g of sodium stearate (9.3% by weight in terms of fatty acids with respect to titanium dioxide) was added. Further, 392 ml of an aqueous sodium aluminate solution (7% by weight in terms of Al ₂ O _{3 with} respect to titanium dioxide) is added while stirring.
After adjusting the pH value to 5.5 by adding an aqueous sodium hydroxide solution, the mixture was aged for 30 minutes. Thereafter, the pH value was adjusted to 7.0 by adding an aqueous sodium hydroxide solution, aged for 30 minutes, filtered, washed, and dried at 85 ° C. for 15 hours.

[0025]

Comparative Example 3 The same processing as in Example 1 was performed except that the operation after the addition of sodium stearate in step 1 was changed as follows. 20 liters of the slurry obtained in the above step (1.4 kg in terms of TiO ₂ ) was heated to 85 ° C., and 140 g of sodium stearate and 392 ml of sodium aluminate solution were added simultaneously with stirring to obtain a pH value. Was adjusted to 5.5 and then aged for 30 minutes.
After ripening, the pH was adjusted to 7.0, ripened for 30 minutes, filtered, washed, and dried at 85 ° C for 15 hours.

[0026]

Comparative Example 4 In step 2, aging was performed after adjusting the pH value after adding sodium stearate to 5.0 using an aqueous hydrochloric acid solution, and the adjusted pH after aging for 1 hour in step 3 was adjusted to an aqueous hydrochloric acid solution. The same processing as in Example 1 was performed, except that 5.5 was added.

[0027]

[Test example] 1. Measurement of Light Fastness The fine particle titanium dioxide coating compositions obtained in each of the examples and comparative examples are mixed for 3 minutes with fine particle titanium dioxide / butylene glycol = 1/1. These pastes were placed on a white board, a cover glass was placed, and the color tone L ₀ , a ₀ , b ₀ of each sample was measured using a colorimeter (CR manufactured by Minolta Co., Ltd.).
-200). After exposing these samples to sunlight for one hour, they are measured again as L ₁ , a ₁ , and b ₁ in the same manner as described above. Then, the degree of discoloration (ΔE) of each sample was determined by the following equation. Table 1 shows the results. The lower the numerical value of ΔE, the better the light resistance.

ΔE = [(L ₁ −L ₀ ) ² + (a ₁ −a
₀ ) ² + (b ₁ −b ₀ ) ² ] ^1/2 L ₀ , a ₀ , b ₀ : color tone before sun exposure L ₁ , a ₁ , b ₁ : color tone after sun exposure

2. Evaluation of Hydrophobicity The hydrophobicity of the fine particle titanium dioxide coating composition obtained in each of Examples and Comparative Examples was measured using a hydrophobicity analyzer (WET-
100P). Table 1 shows the results. The higher the methanol concentration at the start and end points of wetting, that is, the larger the numerical value, the better the hydrophobicity.

3. Evaluation of Sunscreen Cream Sunscreen creams were prepared using the fine particle titanium dioxide coating compositions obtained in each of the Examples and Comparative Examples in the formulations shown in Table 2. Mixing method: Heat and mix oil phase components at 80 ° C,
The aqueous phase component heated and mixed at ℃ was added, stirred with a homomixer (M type manufactured by Tokushu Kika Kogyo Co., Ltd.), and then cooled. Each of the obtained creams was applied to a polypropylene film (thickness: 40).
.mu.m) to a thickness of 12 .mu.m and a wavelength of 250 using a spectrophotometer (U-3300 manufactured by Hitachi, Ltd.).
The transmittance of the film at nm to 700 nm was measured.
Further, with respect to the wavelength between 250 nm and 400 nm, the transmittance integrated value was obtained using the following equation. Table 1 shows the results. 2
The smaller the transmittance integrated value in the range of 50 nm to 400 nm, the more the ultraviolet rays are shielded, and the better the dispersibility. Transmittance integral value (nm ·%) = set wavelength region (n
m) x transmittance (%)

[0031]

Oil phase: Sorbitan sesquiisostearate 2.5% by weight Polyoxyalkylene dimethyl polysiloxane 2.0% by weight Microwax 6.0% by weight Neopentyl glycol Decaplate 15.0% by weight Methylphenyl polysiloxane 21.7% by weight Propyl paraben 0.1% by weight Custer wax 0.5% by weight Titanium dioxide coating composition obtained in each Example or Comparative Example 5.0% by weight Aqueous phase: purified water 40.5% by weight butylene glycol 5.0% by weight Methyl paraben 0.2% by weight 1.5% by weight of sodium chloride

[0032]

[Table 1]

Comparative Example 1 shows the results when the addition amount of the aluminum compound (total treatment amount of Al ₂ O ₃ ) was small. As is clear from the ΔE values in Table 1, the light fastness decreases. In Comparative Examples 2 and 3, in addition to the conditions of Comparative Example 1, the treatment of aluminum hydrated oxide with a fatty acid or a water-soluble salt thereof was performed in a different order from the method of the present invention. As is clear from the transmittance integrated value in Table 1 and the transmittance curve graph in FIG. 1, the light resistance is greatly reduced, and the ultraviolet ray shielding ability is also significantly reduced. Comparative Example 4 shows the results when the pH during ripening was adjusted to be acidic. As is clear from the numerical values in Table 1, all the characteristics are degraded.

[Brief description of the drawings]

FIG. 1 is a transmittance curve at a wavelength of 250 to 700 nm for a sample formulated as a sunscreen using the particulate titanium dioxide coating composition obtained in each of Examples and Comparative Examples.

Claims (3)

[Claims] 1. A cosmetic comprising, as an active ingredient, a titanium dioxide coating composition obtained through the following steps (1) to (3). (1) A water-soluble aluminum salt was added to an aqueous suspension of titanium dioxide having a particle diameter of 0.1 μm or less as Al ₂ O _3.
After addition of 重量 15% by weight (based on titanium dioxide), the pH of the system is adjusted to 5-8 using an acid or base neutralizer. (2) The temperature of the system is raised to 80 ° C. or higher by heating, and a fatty acid having 7 or more carbon atoms or a water-soluble salt thereof is added to the system at 10 to 20% by weight (based on titanium dioxide) in terms of fatty acid.
Then, the pH of the system is adjusted to 7 to 7 using an acid or base neutralizing agent.
9 and aged for 30 minutes or more in this state. (3) After aging, the pH of the system is adjusted to 6.5 to 7.5, and then filtration, washing, drying, and pulverizing operations are performed. 2. The cosmetic according to claim 1, wherein the titanium dioxide used in the step (1) is a titania sol having a rutile crystal structure. 3. A cosmetic comprising the titanium dioxide coating composition of claim 1 in an amount of 1 to 80% by weight based on the total amount of the cosmetic.