JP2010089989A - Spherical cerium oxide and method for producing the same, and cosmetic formulated with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide spherical cerium oxide which has sufficiently suppressed catalytic activity and has ultraviolet screening property in a wide wavelength region and a method for producing the same. <P>SOLUTION: A product obtained by reacting an aqueous solution of a cerium salt compound with an alkali compound having carbon and oxygen atoms is fired to obtain the objective spherical cerium oxide uniform in particles and having an average particle diameter of 100-500 nm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to spherical cerium oxide having uniform particles, a method for producing the same, and a cosmetic containing the spherical cerium oxide.

  In recent years, it has become widely known that ultraviolet rays adversely affect not only living organisms but also various substances. It is known that ultraviolet rays in the UVB region having a wavelength of 280 nm to 320 nm cause skin irritation, and ultraviolet rays in the UVA region having a wavelength of 320 nm to 400 nm promote melanin production and cause browning of the skin. As measures against such adverse effects of ultraviolet rays, organic and inorganic ultraviolet shielding agents are widely used.

  Organic UV screening agents include cinnamic acid compounds, benzophenone compounds, paraaminobenzoic acid compounds, etc., but these are organic compounds, so they lack heat resistance and weather resistance. Since it is gradually decomposed, there is a problem that it is chemically unstable. In addition, when used as a cosmetic, there are many that cause skin irritation and allergic reactions, and there are restrictions on use regulations and blending amounts.

  Examples of the inorganic ultraviolet shielding agent include fine particle titanium oxide and fine particle zinc oxide. These inorganic ultraviolet shielding agents are attracting attention because they have higher safety and stability than organic ultraviolet shielding agents.

  However, fine particle titanium oxide is excellent in shielding the UVB region, but does not shield the UVA region. Further, since the refractive index is high, the transparency in the visible light region is inferior, and there are problems such as whitening when used for cosmetics. On the other hand, although fine zinc oxide shields the UVA region and the UVB region, the shielding of the UVB region is not stronger than that of the fine particle titanium oxide, and when used for cosmetics, there is a problem of elution due to sweat or the like.

  In order to improve these problems, it has been proposed to further refine fine particle titanium oxide, fine particle zinc oxide and the like, but in such a case, the surface activity of the powder will be increased instead, and the fine particle There is a concern that the powdered powder may irritate the skin itself. Moreover, the space | interval between the cells of skin is about 40 nm-60 nm, and there exists a possibility that the micronized powder may permeate | transmit and accumulate | store in a body through skin.

  For this reason, in Europe and the United States, those having a particle size of 100 nm or less are highly concerned about safety, and the current situation is that the use of finely divided titanium oxide and zinc oxide is refrained as much as possible.

  Many conventional spherical cerium oxides have a particle diameter of less than 100 nm, and spherical cerium oxides exceeding 100 nm have irregular shapes and particle sizes (see Patent Documents 1 and 2).

Special table 2008-508175 gazette JP 2007-153731 A

  The present invention has been made in view of the above-described problems. The present invention provides uniform spherical particles having an average particle diameter of 100 nm to 500 nm, sufficiently suppresses the catalytic activity, and further ultraviolet rays in a wide range of wavelengths. An object of the present invention is to provide a shielding cerium oxide and a method for producing the same. Another object of the present invention is to provide a cosmetic that has a high ultraviolet shielding effect, is excellent in safety, and has a good feeling of use by blending this cerium oxide.

  In order to achieve the above-mentioned object, the present inventors have made extensive research efforts, and as a result, by firing a product obtained by reacting an aqueous solution of a cerium salt compound with an alkali compound having a carbon atom and an oxygen atom, the average particle size is obtained. Is capable of obtaining spherical cerium oxide having a uniform diameter of 100 nm to 500 nm, and by blending the obtained spherical cerium oxide into cosmetics, it has a high ultraviolet shielding effect in a wide wavelength region. Thus, it is possible to obtain a cosmetic that is excellent in safety and has a good feeling of use.

In short, the spherical cerium oxide according to the first invention is
The average particle diameter is 100 nm to 500 nm, and the ratio of the major axis to the minor axis of the particles is 1 or more and 1.1 or less.

  The second invention is characterized in that, in the first invention, the ratio of the standard deviation of the particle diameter to the average particle diameter of the particles is 0.3 or less.

Furthermore, in the first invention or the second invention, the third invention has a transmittance of 10 to 30 μm having a wavelength of 350 nm when mixed and kneaded with dimethylpolysiloxane of 1000 centipoise or more so that the particle concentration becomes 10%. Are both 5% or less at a wavelength of 320 nm, or both are 5% or more and 30% or less, and show transmittance at wavelengths of 350 nm and 320 nm satisfying the following formula.
[Transmissivity (320 nm)] / [Transmittance (350 nm)]-1 ≦ 0.1

The method for producing spherical cerium oxide according to the fourth invention comprises:
A method for producing the spherical cerium oxide according to any one of the first to third inventions,
A product obtained by hydrolysis reaction of an aqueous solution of cerium salt and an alkali compound having a carbon atom and an oxygen atom in the molecule is calcined at 300 ° C to 1000 ° C.

The cosmetic according to the fifth invention is
The spherical cerium oxide according to any one of the first to third inventions is blended.

  The spherical cerium oxide of the present invention is uniform spherical particles having an average particle diameter of 100 nm to 500 nm, has extremely low catalytic activity, and has ultraviolet shielding properties in a wide range of wavelengths. Therefore, cosmetics formulated with this powder can reduce the deterioration of ingredients such as fats and oils in cosmetics and the generation of odor changes based on them, and have a high UV shielding effect in a wide range of wavelengths, and are excellent in safety. It becomes a cosmetic with good usability.

  Next, specific embodiments of spherical cerium oxide according to the present invention, a method for producing the same, and a cosmetic compounding the same will be described with reference to the drawings.

  The spherical cerium oxide of the present invention is produced by dissolving a cerium salt compound and an alkali compound having a carbon atom and an oxygen atom in water and heating to form a cerium hydroxide carbonate salt, followed by firing.

  The obtained spherical cerium oxide has a uniform average particle size of 100 nm to 500 nm, and is a spherical particle in which the ratio of the major axis to the minor axis is in the range of 1 ≦ major axis / minor axis ≦ 1.1. . Here, the particle size is measured by taking five photographs of different locations with a scanning electron microscope, measuring 50 primary particles of cerium oxide arbitrarily selected for each photograph, and calculating the average value thereof. To do.

  The standard deviation can be obtained from the particle size and number of individual particles during the observation. The ratio of the standard deviation of the particle diameter to the average particle diameter of the particles according to the present invention is 0.3 or less.

Further, when the spherical cerium oxide of the present invention is mixed and kneaded with dimethylpolysiloxane of 1000 centipoise or more so that the spherical cerium oxide powder particles are 10%, the transmittance of 10 to 30 μm in thickness is 350 nm. Both are 5% or less at 320 nm, or both are 5% or more and 30% or less, and show transmittances at wavelengths of 350 nm and 320 nm that satisfy the following formula.
[Transmissivity (320 nm)] / [Transmittance (350 nm)]-1 ≦ 0.1

  The cerium salt compound preferably includes a cerium nitrate compound, a cerium chloride compound, and a cerium sulfate compound. This is because cerium nitrate compounds, cerium chloride compounds, and cerium sulfate compounds are easily available and are water-soluble.

  The alkali compound having a carbon atom and an oxygen atom may be any alkali compound that can produce a cerium hydroxide carbonate salt when mixed with water and heated with a cerium salt compound, and among them, urea is particularly preferable. preferable.

  Because urea is not only easily available, but when heated in water, urea decomposes into carbonate and ammonium ions, which are uniformly present in the solution, creating spherical particles with uniform particle sizes. This is because a product is obtained.

  Here, the alkali compound is added in excess of the stoichiometric amount, but the preferred range of the addition amount is 20 times or more, more preferably 40 to 60 times. When the addition amount of the alkali compound is less than 20 times the stoichiometric amount in the reaction with the cerium salt compound, the ultraviolet shielding effect does not function, or non-spherical cerium oxide may be generated.

  The heating temperature when heating the mixed liquid of the cerium salt compound, the alkali compound and water is preferably 70 ° C to 100 ° C, more preferably 90 ° C to 100 ° C. When the heating temperature is less than 70 ° C., the time required for the reaction to be generated is significantly increased. The heating time is preferably 30 minutes to 4 hours.

  The firing temperature for firing the cerium hydroxide carbonate salt is preferably 300 ° C. or higher, and the firing time is preferably 1 hour or longer. If the firing time is less than 1 hour, it is not preferable because uneven firing occurs in the fired product and a uniform fired product cannot be obtained.

  In the obtained spherical cerium oxide, the ratio of the major axis to the minor axis of the corresponding particle is in the range of 1 ≦ major axis / minor axis ≦ 1.1, and the ratio of the standard deviation of the particle diameter to the average particle diameter is 0.3 or less. Some uniform spherical particles.

The obtained spherical cerium oxide can be subjected to various surface treatments known per se. Examples of this surface treatment include the following. A plurality of these processes can be used in combination.
a) Fluorine compound treatment: perfluoroalkyl phosphate treatment or perfluoroalkylsilane treatment, perfluoropolyether treatment, fluorosilicone treatment, fluorinated silicone resin treatment, etc.
b) Silicone treatment: methylhydrogenpolysiloxane treatment, dimethylpolysiloxane treatment, vapor phase tetramethyltetrahydrogencyclotetrasiloxane treatment, etc.
c) Pendant treatment: a method of adding an alkyl chain or the like after the gas phase method silicone treatment.
d) Silane coupling treatment e) Titanium coupling treatment f) Aluminum coupling treatment g) Silane treatment: alkylated silane or alkylated silazane treatment.
h) Oil agent treatment i) N-acylated lysine treatment j) Polyacrylic acid treatment k) Metal soap treatment... Stearate treatment or myristate treatment.
l) Acrylic resin treatment m) Metal oxide treatment

  Next, the cosmetic according to the present invention will be described. The cosmetic of the present invention has an excellent ultraviolet shielding effect by blending the above-described spherical cerium oxide of the present invention. In addition, since the spherical cerium oxide of the present invention has a very low catalytic activity, cosmetics formulated with this powder have components such as fats and oils in cosmetics compared to conventional cosmetics formulated with cerium oxide. It is possible to reduce troubles such as deterioration and generation of odors based on the deterioration. That is, there is an advantage that the product stability of the cosmetic can be improved. As a cosmetic dosage form, it can be used for skin care cosmetics such as emulsions and lotions, makeup cosmetics such as foundations and lipsticks, hair cosmetics and the like, and sunscreen cosmetics are particularly preferred. The blending amount is not particularly limited, but is preferably 0.1 to 70% by mass.

  In the cosmetic according to the present invention, the effect becomes remarkable by combining an organic ultraviolet shielding agent and a fine inorganic ultraviolet shielding agent. As the organic ultraviolet shielding agent, one or more selected from oxybenzone, octyl methoxycinnamate, and 4-tert-4'-methoxybenzoylmethane are preferable. Although the compounding quantity of an organic type ultraviolet shielding agent is not specifically limited, Preferably it is 0.1-40 mass%. The fine inorganic UV-screening agent is preferably titanium oxide and / or zinc oxide, more preferably fine particle titanium oxide and / or zinc oxide having an average particle size of 0.05 μm or less. The blending amount of the fine inorganic inorganic ultraviolet shielding agent is not particularly limited, but is preferably 0.1 to 50% by mass.

  Furthermore, the cosmetics of the present invention include components usually used in cosmetics, such as powders, surfactants, oils, gelling agents, polymers, cosmetic ingredients, moisturizers, pigments, preservatives, and fragrances. It can be used as long as the effects of the invention are not impaired.

  Next, spherical cerium oxide according to the present invention, a method for producing the same and examples of cosmetics containing the same will be described. In addition, this invention is not limited by the Example given here.

Example 1
Cerium nitrate hexahydrate (manufactured by Kanto Chemical Co., Inc.) 3.43 g and urea (manufactured by Kanto Chemical Co., Ltd.) 30.32 g are dissolved in 500 g of water, heated at 40 ° C., and then heated at 40 ° C. for 15 minutes to 90 ° C. After raising the temperature of the mixed solution to 90 ° C., it was heated at 90 ° C. for 1 hour. The produced cerium hydroxide carbonate salt was dehydrated by suction filtration with an aspirator, washed with water and dried. The dried cerium hydroxide carbonate was fired at 400 ° C. for 1 hour and pulverized to obtain cerium oxide. A photograph of a scanning electron microscope taken with a scanning electron microscope (manufactured by Hitachi Science Systems, Ltd., model: S-3400N) is shown in FIG. In addition, photographs of five different places (Photos 1 to 5) were taken, and the average particle size and standard deviation of 50 cerium oxides arbitrarily selected for each photo and the standard of the particle size with respect to the average particle size. Deviation ratio was calculated. The results are shown in Table 1. The average particle diameter of the cerium oxide was uniform spherical particles of about 150 nm. The transmittance at wavelengths of 320 nm and 350 nm when mixed with 2000 centipoise dimethylpolysiloxane so that the resulting spherical particles are 10%, and kneaded with a Hoovermarler and applied to a glass cell so as to be 20 μm, 0% and 1%.

(Example 2)
Cerium chloride heptahydrate (manufactured by Kanto Chemical Co., Inc.) 3.43 g and urea (manufactured by Kanto Chemical Co., Ltd.) 30.32 g are dissolved in 500 g of water, heated at 40 ° C., and then heated at 40 ° C. for 15 minutes to 90 ° C. After raising the temperature of the mixed solution to 90 ° C., it was heated at 90 ° C. for 1 hour. The produced cerium hydroxide carbonate salt was dehydrated by suction filtration with an aspirator, washed with water and dried. The dried cerium hydroxide carbonate was fired at 400 ° C. for 1 hour and pulverized to obtain cerium oxide. The photograph of the scanning electron microscope which image | photographed powder with the scanning electron microscope (Hitachi Science Systems Co., Ltd. make, model | form: S-3400N) is shown in FIG. Also, photographs of five different places (Photos 1 to 5) were taken, and the average particle size and standard deviation of 50 cerium oxides arbitrarily selected for each photo, and the standard of the particle size with respect to the average particle size. Deviation ratio was calculated. The results are shown in Table 2. The average particle diameter of the cerium oxide was uniform and spherical particles of about 280 nm. The transmittance at wavelengths of 320 nm and 350 nm when mixed with 2000 centipoise dimethylpolysiloxane so that the resulting spherical particles are 10%, and kneaded with a Hoovermarler and applied to a glass cell so as to be 20 μm, 24% and 25%.

(Comparative Example 1)
Commercially available fine particle titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., trade name: TTO-51 (A), primary particle diameter: 10 nm to 30 nm) was prepared.

(Comparative Example 2)
Commercially available fine particle zinc oxide (manufactured by Teika Co., Ltd., trade name: MZ-500, primary particle diameter 20 nm to 40 nm) was prepared.

For the powders of Examples 1 and 2 and Comparative Examples 1 and 2, the activity was measured using the pulse reactor method. Two pieces of glass wool cut into approximately 1 cm square were packed at the bottom of the reaction tube, and 0.2 g of powder was put into the reaction tube. Two pieces of 1 cm square glass wool were packed on top of this to prepare for pretreatment. Measurement was performed by gas chromatography under the following conditions (manufactured by CE Instruments, model: GC8000 Top), the area ratio of peaks of propylene, acetone, isopropyl alcohol (hereinafter abbreviated as “IPA”) was calculated, and the IPA residual ratio was obtained. . In addition, since the above method is a reaction in which IPA is decomposed into propylene or acetone by the surface activity of the powder, the higher the IPA residual ratio value, the lower the surface activity.
[Gas chromatography conditions]
Column used: Propak R80 / 100 3m packed column injection volume: IPA 2 μl
Inlet temperature: 280 ° C
Detector temperature: 180 ° C
Column temperature: 80 ° C. (heating rate: 7.5 ° C./min)−180° C. (12 min hold)
Carrier gas ... Helium (20ml / min)

  Table 3 shows the results of activity measurement by the pulse reactor method in Examples 1 and 2 and Comparative Examples 1 and 2 under the above conditions.

  As is apparent from Table 3, it can be seen that the powders of Comparative Examples 1 and 2 have a lower IPA residual rate and higher activity than the powders obtained in Examples 1 and 2.

  Next, the ultraviolet shielding ability of the powders of Examples 1 and 2 and Comparative Examples 1 and 2 was examined. The UV shielding ability was measured by adding 2 g of silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KF-96-2000cs) to 0.2 g of powder, kneading 50 times and 3 times with a Hoovermarler. A solution was prepared. The test solution was put in an assembled cell (thickness 10 μm to 30 μm) and a test was performed. The transmittance of the test solution at wavelengths of 300 nm, 400 nm, and 700 nm was measured with an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model: V-570 type).

  Table 4 shows the results of measuring the ultraviolet absorption ability under the above conditions.

  The powders obtained in Examples 1 and 2 had low transmittance at a wavelength of 300 nm in the UVB region and low transmittance at a wavelength of 400 nm in the UVA region. However, although the powders of Comparative Examples 1 and 2 had a low transmittance at a wavelength of 300 nm in the UVB region, the transmittance at a wavelength of 400 nm in the UVA region was higher than those in Examples 1 and 2. That is, it can be seen that the powders of Examples 1 and 2 have an excellent ultraviolet shielding ability in both the UVA region and the UVB region.

(Example 3)
Using the spherical cerium oxide obtained in Examples 1 and 2, a cream foundation was prepared by the following composition and preparation method.
Ingredient Mass%
(1) Stearic acid 5.0
(2) Lipophilic glyceryl monostearate 2.5
(3) Cetanol 1.5
(4) Isopropylene glycol monolaurate 2.5
(5) Liquid paraffin 8.0
(6) Isopropyl myristate 7.0
(7) Propyl paraoxybenzoate 0.1
(8) Purified water remaining amount (9) Triethanolamine 1.2
(10) Sorbitol 3.0
(11) Methyl paraoxybenzoate 0.2
(12) Titanium oxide 8.0
(13) Kaolin 5.0
(14) Spherical cerium oxide 3.0
(15) Bentonite 1.0
(16) Bengala 2.5
(17) Yellow iron oxide 2.0
(18) Black iron oxide 0.2

Preparation method a. (12)-(14) and (16)-(18) are mixed well.
B. Add (15) to (8) at 80 ° C. and swell well. Next, (9) to (11) are added and dissolved. To this thing i. And the mixture is dissolved at 80 ° C. (aqueous phase).
C. (1) to (7) are dissolved at 80 ° C. (oil phase).
D. Add (oil phase) to (water phase) and emulsify. Thereafter, the mixture is cooled and stirred to 35 ° C.
The cream foundation obtained as described above had a sense of transparency, extended well, was excellent in ultraviolet shielding effect, and had good stability because of reduced catalytic activity.

Example 4
Using the spherical cerium oxide obtained in Examples 1 and 2, sunscreen emulsions were prepared by the following composition and preparation method.
Ingredient Mass%
(1) Spherical cerium oxide 10.0
(2) Acrylic silicone copolymer solution 1.0
(3) Glyceryl triisooctanoate 5.0
(4) Squalane 5.0
(5) Methylpolysiloxane (10CS) 10.0
(6) Decamethylcyclopentasiloxane 20.0
(7) Sorbitan sesquioleate 4.0
(8) Polyoxyethylene / methylpolysiloxane copolymer 2.0
(9) Oxybenzone 0.1
(10) 1,3-butylene glycol 9.0
(11) Preservative appropriate amount (12) Purified water appropriate amount (13) Fragrance appropriate amount

Preparation method a. (2) to (9) were dissolved, and (1) was added thereto and kneaded well.
B. (10) to (12) were dissolved and added to a and emulsified and mixed.
C. (13) was added to and mixed with B to obtain a sunscreen emulsion.
The sunscreen emulsion obtained as described above had a sense of transparency, a good makeup, an excellent ultraviolet shielding effect, and good stability due to reduced catalytic activity.

(Comparative Example 3)
When the cream foundation was prepared according to the formulation of Example 3 using the fine particle titanium oxide and the fine particle zinc oxide prepared in Comparative Examples 1 and 2, the ultraviolet ray shielding effect was excellent, but the catalytic activity was high, so the stability was high. Was bad.

(Comparative Example 4)
Using the fine particle titanium oxide and fine particle zinc oxide prepared in Comparative Examples 1 and 2, a sunscreen emulsion was prepared according to the formulation of Example 4, and the UV shielding effect was excellent, but the feel when applied to the skin. Was bad.

  The spherical cerium oxide of the present invention can be obtained by blending with cosmetics such as cream foundation or sunscreen emulsion to provide a cosmetic with transparency, excellent ultraviolet shielding effect and good stability.

Electron micrograph of spherical cerium oxide according to Example 1 of the present invention. Electron micrograph of spherical cerium oxide according to Example 2 of the present invention

Claims (5)

  Spherical cerium oxide having an average particle diameter of 100 nm to 500 nm and a ratio of the major axis to the minor axis of the particles of 1 or more and 1.1 or less.   2. The spherical cerium oxide according to claim 1, wherein the ratio of the standard deviation of the particle diameter to the average particle diameter of the particles is 0.3 or less. When mixed and kneaded with dimethylpolysiloxane of 1000 centipoise or more so that the particle concentration is 10%, the transmittance at a thickness of 10 to 30 μm is 5% or less at both wavelengths of 350 nm and 320 nm, or both are 5% The spherical cerium oxide according to claim 1 or 2, wherein the spherical cerium oxide is 30% or less and exhibits transmittance at a wavelength of 350 nm and a wavelength of 320 nm satisfying the following formula.
[Transmissivity (320 nm)] / [Transmittance (350 nm)]-1 ≦ 0.1 A method for producing the spherical cerium oxide according to any one of claims 1 to 3,
A method for producing spherical cerium oxide, comprising calcining a product obtained by hydrolysis reaction of an aqueous solution of cerium salt and an alkali compound having carbon and oxygen atoms in the molecule at 300 ° C to 1000 ° C.   A cosmetic comprising the spherical cerium oxide according to any one of claims 1 to 3.

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