JP2007106715A - Oil-in-water type external preparation for skin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil-in-water type external preparation for skin, improved in a sense of use, dispersion stability of a powder, and emulsion stability, when compounded of a hydrophobically treated powder and a dibenzoylmethane-based compound, and capable of preventing the dibenzoylmethane-based compound from discoloring with the lapse of time. <P>SOLUTION: This oil-in-water type external preparation for skin comprises the hydrophobically treated powder, the dibenzoylmethane-based compound, a polyglycerol derivative having a specific structure, and a block-type alkylene oxide derivative having a specific structure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an oil-in-water external preparation for skin, in particular, its feeling of use, powder dispersibility, improvement in emulsion stability, and suppression of discoloration over time of dibenzoylmethane compounds.

  Conventionally, various skin external preparations containing inorganic powders such as titanium oxide and zinc oxide have been widely used. As a base for these external preparations for skin use, a water-in-oil emulsion base or a powder base is mainly used, but there are many cases where a good feeling of use cannot be obtained due to a strong oily feeling and powdery feeling. . On the other hand, oil-in-water type emulsion bases are used in cosmetics such as emulsions, creams, and emulsified foundations because they have a fresh feeling of use.

  However, in the case of an oil-in-water emulsified base containing an inorganic powder, there is a problem that the powder aggregates, and the necessity of uniformly dispersing the powder has arisen. For example, in the case of a sunscreen cosmetic that imparts an ultraviolet protection function, if the powder remains agglomerated, there are various problems such as a cause of a decrease in the ultraviolet protection effect and a different feeling in use. Therefore, a technology has been developed in which a hydrophobized powder obtained by hydrophobizing the surface of an inorganic powder such as titanium oxide or zinc oxide is mixed with an oil-in-water emulsion. Property and emulsion stability were not sufficient. Moreover, as a feeling of use, although a moist feeling was obtained after use, there was a problem that a sticky feeling was produced.

  In order to solve these problems, a technique for imparting dispersion stability by preventing coalescence of emulsified particles, agglomeration and sedimentation of fine powder particles due to aging, temperature change, and the like (for example, Patent Documents 1 and 2). However, these techniques are still not sufficient in terms of dispersion stability, emulsification stability, and feel of use of the hydrophobized powder. Moreover, in recent years, in order to give a better UV blocking ability, during the formulation of sunscreen cosmetics, hydrophobized titanium oxide that is mainly effective for UV-B and mainly UV-A. There is a need for a technology that allows effective coexistence with hydrophobized zinc oxide, but the presence of titanium oxide and zinc oxide with different surface states causes significant aggregation and coalescence of emulsified particles. Therefore, it was very difficult to satisfy the dispersibility and the emulsion stability.

  In recent years, dibenzoylmethane compounds, which are organic compounds that are effective against UV-A, have been used for the purpose of imparting better UV protection, and are widely used especially in terms of functionality and safety. There is a need for a technique for blending 4-tert-butyl-4′-methoxydibenzoylmethane into an oil-in-water emulsion. It is known that this 4-tert-butyl-4'-methoxydibenzoylmethane improves the UV protection ability when combined with the above inorganic powder. However, when the dibenzoylmethane compound is blended simultaneously with the inorganic powder, it causes coloring and discoloration over time, so that the appearance is remarkably impaired and the quality as a cosmetic is lowered.

  In order to solve these problems, there has been a method in which the discoloration is preliminarily applied to the cosmetic to make the discoloration due to 4-tert-butyl-4′-methoxydibenzoylmethane inconspicuous. At present, there is no solution for reducing the UV absorption ability. Also, a method using a sequestering agent selected from edetic acid, metaphosphoric acid, polyphosphoric acid or salts thereof (see, for example, Patent Document 3), a method of coating and / or treating titanium dioxide with silicone (for example, patents) In addition, the surface of fine titanium dioxide is coated with 15 to 50% by mass of silica, and a composite pigment having an average particle size of 0.01 to 0.2 μm is blended, thereby producing a pale yellow 4-tert. A method for preventing crystal precipitation of -butyl-4'-methoxydibenzoylmethane (for example, see Patent Document 5) is known.

  However, both the method using a sequestering agent and the method of coating and / or treating titanium dioxide with silicone were incomplete methods to suppress significant discoloration in a system in which water coexists. In addition, the method of blending a composite pigment in which silica is coated on the surface of fine particle titanium dioxide requires that the surface of fine particle titanium dioxide be coated at a high rate in order to obtain a discoloration suppressing effect. Therefore, in sunscreen cosmetics, it is necessary to mix a large amount of complex pigments in order to fully exhibit the UV protection effect of titanium dioxide, so that the feeling of use is lowered, and furthermore, the dispersion stability is inferior. was there.

Japanese Patent Publication No. 7-94366 JP-A-8-310940 JP-A-61-215314 Japanese Patent Laid-Open No. 9-2929 Japanese Patent Laid-Open No. 11-217322

  The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to provide a feeling of use when a hydrophobized powder and a dibenzoylmethane compound are blended, and dispersion of the powder. An object of the present invention is to provide an oil-in-water type skin external preparation which has improved stability and emulsion stability and further suppresses discoloration of a dibenzoylmethane compound over time.

  As a result of intensive studies by the present inventors to achieve the above object, a polyglycerin derivative having a specific structure was formulated in an oil-in-water type skin external preparation containing a hydrophobized powder and a dibenzoylmethane-based compound. And a block-type alkylene oxide derivative having a specific structure, the feeling of use, the dispersion stability of the powder and the emulsion stability are remarkably improved, and the discoloration with time of the dibenzoylmethane compound is suppressed. I found. In particular, when both hydrophobized titanium oxide and hydrophobized zinc oxide and 4-tert-butyl-4'-methoxydibenzoylmethane are blended, the feeling of use, powder dispersion stability and emulsion stability are excellent. And it discovered that the oil-in-water type skin external preparation which has the outstanding discoloration suppression effect was obtained, and came to complete this invention.

（式中、ｍ＋２はポリグリセリンの平均重合度を表しており１≦ｍ≦４、Ｒ^１は炭素数１〜４の炭化水素基又は水素原子、ＡＯは炭素数３〜４のオキシアルキレン基、ｎはオキシアルキレン基の平均付加モル数で、１≦ｍ×ｎ≦２００である。）
Ｒ^１Ｏ−（ＡＯ）_ｍ（ＥＯ）_ｎ−Ｒ^２ （２）
（式中、ＡＯは炭素数３〜４のオキシアルキレン基、ＥＯはオキシエチレン基、ｍおよびｎはそれぞれ前記オキシアルキレン基、オキシエチレン基の平均付加モル数で、１≦ｍ≦７０、１≦ｎ≦７０である。炭素数３〜４のオキシアルキレン基とオキシエチレン基はブロック状に付加しており、炭素数３〜４のオキシアルキレン基とオキシエチレン基の合計に対するオキシエチレン基の割合は２０〜８０質量％である。Ｒ^１およびＲ^２は同一もしくは異なっていてもよく炭素数１〜４の炭化水素基または水素原子であり、Ｒ^１およびＲ^２の炭化水素基数に対する水素原子数の割合は０．１５以下である。） That is, the oil-in-water type external preparation for skin according to the present invention is represented by a hydrophobized powder, a dibenzoylmethane compound, a polyglycerin derivative represented by the following general formula (1), and the following general formula (2). The block-type alkylene oxide derivative is contained.

(In the formula, m + 2 represents the average degree of polymerization of polyglycerol, 1 ≦ m ≦ 4, R ¹ is a hydrocarbon group or hydrogen atom having 1 to 4 carbon atoms, AO is an oxyalkylene group having 3 to 4 carbon atoms, n is the average added mole number of the oxyalkylene group, and 1 ≦ m × n ≦ 200.
R ¹ O— (AO) _m (EO) _n —R ² (2)
(In the formula, AO is an oxyalkylene group having 3 to 4 carbon atoms, EO is an oxyethylene group, m and n are average addition moles of the oxyalkylene group and oxyethylene group, respectively, 1 ≦ m ≦ 70, 1 ≦ n ≦ 70 The oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group are added in a block form, and the ratio of the oxyethylene group to the total of the oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group is R ¹ and R ² may be the same or different and each is a hydrocarbon group having 1 to 4 carbon atoms or a hydrogen atom, and the number of hydrogen atoms relative to the number of hydrocarbon groups represented by R ¹ and R ² The ratio is 0.15 or less.)

In the oil-in-water type external preparation for skin, it is preferable that the hydrophobized powder includes hydrophobized fine particle titanium dioxide and hydrophobized fine particle zinc oxide. In the oil-in-water type external preparation for skin, it is preferable that 4-tert-butyl-4′-methoxydibenzoylmethane is contained as the dibenzoylmethane compound. In the oil-in-water type external preparation for skin, it is preferable to further contain one or more selected from succinoglycan, xanthan gum and acrylamide. In the oil-in-water type external preparation for skin, it is preferable to further contain one or more selected from carboxymethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, and gelatin.
The sunscreen cosmetic according to the present invention comprises the oil-in-water type skin external preparation.

  According to the present invention, a polyglycerin derivative having a specific structure and a block type alkylene oxide derivative having a specific structure are blended in an oil-in-water type skin external preparation formulation containing a hydrophobized powder and a dibenzoylmethane compound. Thus, the feeling of use, the dispersion stability of the powder, and the emulsion stability are improved, and the discoloration with time of the dibenzoylmethane compound is suppressed. In particular, when both hydrophobized titanium oxide and hydrophobized zinc oxide and 4-tert-butyl-4'-methoxydibenzoylmethane are blended, the powder has excellent dispersion stability and emulsion stability, and is excellent. It has the effect of suppressing discoloration.

（式中、ｍ＋２はポリグリセリンの平均重合度を表しており１≦ｍ≦４、Ｒ^１は炭素数１〜４の炭化水素基又は水素原子、ＡＯは炭素数３〜４のオキシアルキレン基、ｎはオキシアルキレン基の平均付加モル数で、１≦ｍ×ｎ≦２００である。） Hereinafter, the present invention will be described in more detail by giving specific examples, but the present invention is not limited thereto.
Polyglycerin derivative The polyglycerin derivative used in the oil-in-water type external preparation for skin according to the present invention is represented by the following general formula (1).

(In the formula, m + 2 represents the average degree of polymerization of polyglycerol, 1 ≦ m ≦ 4, R ¹ is a hydrocarbon group or hydrogen atom having 1 to 4 carbon atoms, AO is an oxyalkylene group having 3 to 4 carbon atoms, n is the average added mole number of the oxyalkylene group, and 1 ≦ m × n ≦ 200.

  In the polyglycerin derivative represented by the above formula (1), m + 2 represents the average degree of polymerization of polyglycerin, and 1 ≦ m ≦ 4, that is, 3 ≦ m + 2 ≦ 6. Examples of polyglycerin include triglycerin (m = 1), tetraglycerin (m = 2), pentaglycerin (m = 3), and hexaglycerin (m = 4). Triglycerin is particularly preferred. When m is 0 (m + 2 = 2) or m is 5 or more (m + 2 ≧ 7), the surface activity is insufficient.

  In the production of the polyglycerin derivative used in the present invention, the production method of the polyglycerin used as a raw material is not particularly limited, and may be linear or branched. In the above formula (1), only a linear polyglycerin derivative is shown for convenience, but in the present invention, for example, a branched polyglycerin derivative or a mixture thereof may be used. In addition, since commercially available polyglycerol is usually obtained by dehydration condensation, when 1-position or 3-position and 1-position or 3-position of glycerol react, 1-position or 3-position and 2-position react. The position and the 2-position may react, resulting in a linear and branched mixture. When such a mixture is used as a raw material, a polyglycerol derivative is also obtained as a linear and branched mixture.

  The polyglycerin used as a raw material is more preferably a narrowed average polymerization degree distribution of triglycerin, and the polyglycerin content is 75% by mass or more, more preferably 80% by mass or more. By using it, the surface active ability is further improved. In addition, the average polymerization degree distribution of triglycerin can be narrowed by performing distillation or the like. The triglycerin content can be measured, for example, by the following method.

TMS conversion: 0.1 g of sample is weighed into a screw tube, and 0.5 mL of pyridine is added and dissolved. Next, 0.4 mL of hexamethyldisilazane is added and mixed, and further 0.2 mL of chlorotrimethylsilane is added and mixed well. After standing for 30 minutes, the mixture is centrifuged to precipitate pyridine hydrochloride, and the supernatant is filtered and analyzed by gas chromatography.
Detector: FID
Column: HP-5 Crosslinked 5% PH ME Siloxane 0.25 μm × 30 m
Column temperature: 80 ° C. → 320 ° C. (15 ° C./min) 320 ° C., 25 min
Inlet temperature: 320 ° C
Detector temperature: 320 ° C
Carrier gas: Helium Flow rate: 23 cm / sec
Injection volume: 0.2 μL
Split ratio: Splitless

R ¹ is a hydrocarbon group having 1 to 4 carbon atoms or a hydrogen atom, preferably a hydrocarbon group having 1 to 4 carbon atoms. Examples of hydrocarbon groups include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, s-butyl groups, t-butyl groups and other saturated hydrocarbon groups, vinyl groups, allyl groups, etc. An unsaturated hydrocarbon group, a mixture thereof and the like can be mentioned, and a saturated hydrocarbon group is more preferable.

  AO is an oxyalkylene group having 3 to 4 carbon atoms, and examples thereof include an oxypropylene group, an oxybutylene group, an oxyisobutylene group, an oxy t-butylene group, a trimethylene group, a tetramethylene group, and a mixture thereof. The ratio of the oxybutylene group having 4 carbon atoms in the total oxyalkylene group is preferably 50% by mass or more, and more preferably 100% by mass. An oxyalkylene group having 2 or less carbon atoms does not exhibit surface activity, and an oxyalkylene group having 5 or more carbon atoms is difficult to obtain a highly pure derivative. Further, the polymerization form of different oxyalkylene groups may be block or random.

  n is the average number of moles added of the oxyalkylene group, and in combination with m representing the number of hydroxyl groups that can be bonded to the oxyalkylene group, 1 ≦ m × n ≦ 200, preferably 4 ≦ m × n ≦ 100, more preferably 8 ≦ m × n ≦ 70. When mxn is 0, no surface activity is exhibited, and when it exceeds 200, it is difficult to obtain a highly pure derivative. Further, n, which is the average added mole number of the oxyalkylene group, can independently take a value of 1 ≦ n ≦ 200, but preferably 4 ≦ n ≦ 80, more preferably 8 ≦ m ≦ 50.

  Specific examples of the polyglycerin derivative used in the present invention include polyoxybutylene (25 mol) methyltriglyceryl ether, polyoxybutylene (28 mol) methyltriglyceryl ether, and polyoxybutylene (42 mol) methyl. Triglyceryl ether, polyoxybutylene (56 mol) methyltriglyceryl ether, polyoxybutylene (28 mol) triglyceryl ether, polyoxybutylene (42 mol) triglyceryl ether, polyoxybutylene (50 mol) triglyceryl ether, poly And oxybutylene (56 mol) triglyceryl ether.

In addition, the polyglycerol derivative shown by Formula (1) of this invention can be normally manufactured by the procedure of the following 1) -2).
1) A polyglycerol having an average degree of polymerization of 3 to 6 is reacted with a ketalizing agent or an acetalizing agent in the presence of an acid catalyst to obtain a polyglycerol diketal compound or a diacetal compound.
2) Subsequently, an addition reaction of an alkylene oxide having 3 to 4 carbon atoms is carried out in the presence of an alkali catalyst. Further, if necessary, an alkyl (alkenyl) halide is reacted in the presence of an alkali catalyst to convert the oxyalkylene group terminal to an alkyl (alkenyl) ether.
3) Thereafter, deketalization or deacetalization is performed in the presence of an acid catalyst.

A compound for ketalizing or acetalizing polyglycerol is shown in the following formula (3).

R ² and R ³ each represent a hydrocarbon group having 1 to 4 carbon atoms or a hydrogen atom, and R ⁴ and R ⁵ are each a hydrocarbon group having 1 to 4 carbon atoms. However, the case where R ² and R ³ are hydrogen atoms at the same time is excluded. Examples of the hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an s-butyl group, and a t-butyl group, and more preferably a methyl group.

  Examples of the compound of the formula (3) include 2,2-dimethoxypropane, 1,1-dimethoxy-3-butanone, 1,1-dimethoxyethane, and 2,2-dimethoxypropane is more preferable. In addition, although a ketal compound or an acetal compound can be directly synthesized from ordinary ketones or aldehydes, it is more preferable to use the compound of the formula (3) from the viewpoint of the substitution reaction rate of a ketal group or the like. Examples of the ketalization or acetalization catalyst include acid catalysts such as sulfuric acid and paratoluenesulfonic acid. Usually, the amount of the compound of the formula (3) is 250 to 500 mol% with respect to polyglycerol, the amount of the acid catalyst is 0.0005 to 0.015 mol% with respect to polyglycerol, and the reaction temperature is 30 to 30%. It is common to carry out at 70 ° C.

The polyglycerin diketalized product produced by the reaction between polyglycerin and the compound of the above formula (3) is shown in the following formula (4).

  When the polyglycerin diketalized product or diacetalized product of the formula (4) is used in the alkylene oxide addition reaction in the next step, there is no particular need to remove the catalyst, but if necessary, neutralization treatment with alkali And acid adsorption treatment, filtration and the like. For example, neutralizers such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium acetate, Kyowa Chemical Industry Co., Ltd. Kyoward 300, Kyoward 1000, Tomita Pharmaceutical Co., Ltd. Tomix AD-500, etc. Adsorbents, zeolites, etc. can be used.

  The polyglycerin diketalized product or diacetalized product of the formula (4) is described as a reaction product at the 1st and 2nd positions of the terminal glyceryl group, but is not limited to this in the present invention. For example, when branched polyglycerin is used as a raw material, it is ketalized or acetalized at the 1st and 3rd positions, and such a compound can also be used.

  When the compound of formula (4) is subjected to the alkylene oxide addition in the presence of an alkali catalyst, the reaction is usually carried out at a temperature of 40 to 180 ° C. in a pressure reaction kettle such as an autoclave. As the catalyst at this time, oxides, hydroxides, alcoholates or the like of alkali metals or alkaline earth metals can be used. More specifically, for example, sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, sodium methoxide and the like. Although the usage-amount of a catalyst is not specifically limited, 0.01-5.0 mass% is common with respect to the mass after completion | finish of addition reaction.

  After the alkylene oxide addition reaction, if necessary, an alkyl (alkenyl) halide or the like may be reacted in the presence of an alkali catalyst to alkylate the oxyalkylene group terminal. Examples of alkyl (alkenyl) halides include methyl chloride, ethyl chloride, propyl chloride, butyl chloride, vinyl chloride, allyl chloride, methyl bromide, ethyl bromide, methyl iodide, ethyl iodide and the like. Further, as the catalyst at this time, oxides, hydroxides, alcoholates or the like of alkali metals or alkaline earth metals can be used. More specifically, for example, sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, sodium methoxide and the like. The amount of alkyl (alkenyl) halide charged is 100 to 400 mol% with respect to the number of hydroxyl groups to be reacted, the amount of alkali catalyst is 100 to 500 mol% with respect to the number of hydroxyl groups to be reacted, and the reaction temperature is 60 to 160 ° C. It is common.

  When an oxyalkylene product of the compound of formula (4) is subjected to a deketalization or deacetalization reaction in the next step, it is necessary to perform a neutralization treatment with an acid, an alkali adsorption treatment, filtration, or the like. For example, neutralizing agents such as mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, carbonic acid, citric acid, succinic acid, tartaric acid and the like, Kyowa Chemical Industry Co., Ltd. Kyoward 600, Kyoword 700, Adsorbents such as Tomix AD-300 manufactured by Tomita Pharmaceutical Co., Ltd., other zeolites, and the like can be used.

  The deketalization or deacetalization reaction in the oxyalkylenated product of the compound of formula (4) is performed in the presence of an acid catalyst. Examples of the acid catalyst include hydrochloric acid, sulfuric acid, phosphoric acid, p-toluenesulfonic acid, other solid acids, cation exchange resins, and acid clay. The amount of the acid catalyst used is generally 0.01 to 6.0% by mass with respect to the oxyalkylenated product of the compound of formula (4), and the reaction temperature is generally 60 to 150 ° C.

  After completion of the deketal or deacetal reaction, neutralization treatment with an alkali, acid adsorption treatment, filtration, or the like can be performed. For example, neutralizers such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium acetate, Kyowa Chemical Industry Co., Ltd. Kyoward 300, Kyoward 1000, Tomita Pharmaceutical Co., Ltd. Tomix AD-500, etc. Adsorbents, zeolites, etc. can be used.

  As described above, in the production of the polyglycerol derivative used in the present invention, the hydroxyl group at the terminal portion of the polyglycerol is protected in advance by diketalization or diacetalization, and in this state, the hydroxyl group is subjected to an oxyalkylene reaction. Thereafter, a series of steps of removing the protecting group by deketalization or deacetalization reaction is performed. As a result, a polyglycerol derivative in which only the hydroxyl group at the non-terminal portion of the polyglycerol is selectively oxyalkylenated as shown in the formula (1) is obtained.

  In the oil-in-water type external preparation for skin according to the present invention, the blending amount of the polyglycerin derivative is not particularly limited and can be appropriately adjusted according to the purpose of use. It is suitable that it is 0.2-7.0 mass% with respect to the total amount, Furthermore, it is 1.0-5.0 mass%. When the blending amount of the polyglycerin derivative is less than 0.2% by mass, the dispersion stability, the emulsion stability, and the discoloration suppressing effect may be inferior. It is not preferable because phase inversion may occur.

Block type alkylene oxide derivative The block type derivative used in the oil-in-water type external preparation for skin according to the present invention is represented by the following general formula (2).
R ¹ O— (AO) _m (EO) _n —R ² (2)
In the alkylene oxide derivative represented by the above formula (2), AO is an oxyalkylene group having 3 to 4 carbon atoms, specifically, an oxypropylene group, an oxybutylene group, an oxyisobutylene group, an oxytrimethylene group, an oxy Examples include a tetramethylene group. Preferably, an oxypropylene group and an oxybutylene group are mentioned.

m is the average number of moles added of the oxyalkylene group having 3 to 4 carbon atoms, and 1 ≦ m ≦ 70, preferably 2 ≦ m ≦ 50. n is the average number of added moles of oxyethylene groups, and 1 ≦ n ≦ 70, preferably 5 ≦ n ≦ 55. When the oxyalkylene group having 3 to 4 carbon atoms or the oxyethylene group is 0, the moist feeling is lowered, and when it exceeds 70, the sticky feeling is produced.
Moreover, it is preferable that the ratio of the oxyethylene group with respect to the sum total of a C3-C4 oxyalkylene group and an oxyethylene group is 20-80 mass%. When the proportion of the oxyethylene group is less than 20% by mass, the phase may be changed to a water-in-oil type, and when it is greater than 80% by mass, the emulsion stability tends to be inferior.

  The oxyethylene group and the oxyalkylene group having 3 to 4 carbon atoms must be added in a block form, but the order of addition of ethylene oxide and the alkylene oxide having 3 to 4 carbon atoms is not particularly specified. The block shape includes not only two-stage blocks but also three or more stages.

R ¹ and R ² are each a hydrocarbon group having 1 to 4 carbon atoms or a hydrogen atom, and examples of the hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, Examples thereof include a tert-butyl group. A methyl group and an ethyl group are preferred. Hydrocarbon groups having 5 or more carbon atoms tend to have poor hydrophilicity and cause skin irritation. R ¹ and R ² may be the same or different.

R ¹ and R ² may be the same type, or a mixture of a hydrocarbon group having 1 to 4 carbon atoms and a hydrogen atom, or a mixture of different hydrocarbon groups having 1 to 4 carbon atoms. Good. However, among the hydrocarbon groups of R ¹ and R ^2, the proportion of hydrocarbon groups and hydrogen atoms is such that the ratio Y / X of the number of hydrogen atoms (Y) to the number of hydrocarbon groups (X) is 0.15. Hereinafter, it is preferably 0.06 or less. When the ratio of Y / X exceeds 0.15, a sticky feeling comes out.

  The molecular weight of the block-type alkylene oxide derivative is preferably 1000 or more, more preferably 3000 or more. If the molecular weight is less than 1000, the emulsion stability is low. Further, although the upper limit of the molecular weight cannot be specifically defined, as the molecular weight increases, a sticky feeling after coating tends to occur.

Specific examples of the block-type alkylene oxide derivative used in the present invention include POE (14) POP (7) dimethyl ether, POE (17) POP (4) dimethyl ether, POE (10) POP (10) dimethyl ether, POE (7) POP (12) dimethyl ether, POE (15) POP (5) dimethyl ether, POE (25) POP (25) dimethyl ether, POE (27) POP (14) dimethyl ether, POE (55) POP (28) dimethyl ether, POE (22) POP (40) dimethyl ether, POE (35) POP (40) dimethyl ether, POE (50) POP (40) dimethyl ether, POE (36) POP (41) dimethyl ether, POE (55) POP (30) dimethyl ether POE (30) POP (34) dimethyl ether, POE (25) POP (30) dimethyl ether, POE (14) POB (7) dimethyl ether, POE (10) POP (10) diethyl ether, POE (10) POP (10 ) Dipropyl ether, POE (10) POP (10) dibutyl ether and the like.
The POE, POP, and POB are abbreviations for polyoxyethylene, polyoxypropylene, and polyoxybutylene, respectively, and may be abbreviated as follows.

  The block-type alkylene oxide derivative used in the present invention can be produced by a known method. For example, it can be obtained by subjecting a compound having a hydroxyl group to addition polymerization of ethylene oxide and an alkylene oxide having 3 to 4 carbon atoms, and then subjecting an alkyl halide to an ether reaction in the presence of an alkali catalyst.

  In the oil-in-water type external skin preparation according to the present invention, the blending amount of the block-type alkylene oxide derivative is not particularly limited and can be appropriately adjusted according to the purpose of use. It is preferable that it is 0.3-6 mass% with respect to the total amount of 0.5, Furthermore, it is 0.5-4 mass%. If it is less than 0.3% by mass, emulsification may not be sufficient, and if it exceeds 6% by mass, a sticky feeling may occur after coating.

Hydrophobized powder The hydrophobized powder used in the oil-in-water type external preparation for skin according to the present invention is not particularly limited as long as the surface of the powder is hydrophobized. Silicone powders such as methylhydrogenpolysiloxane and dimethylpolysiloxane, dextrin fatty acid ester, higher fatty acid, higher alcohol, fatty acid ester, metal soap, alkyl phosphate ether, fluorine compound, squalane, paraffin, etc. And hydrophobized by a wet method using a solvent, a gas phase method, a mechanochemical method, or the like. The average particle size of the hydrophobized powder needs to be smaller than the emulsified particles that are the oil phase of the present invention. In particular, when powder is used as an ultraviolet scattering agent, it is preferable that the average particle size after crushing with a wet disperser is 100 nm or less. Examples of the inorganic powder particles to be hydrophobized include titanium oxide, zinc oxide, talc, mica, sericite, kaolin, titanium mica, black iron oxide, yellow iron oxide, bengara, ultramarine blue, bitumen, chromium oxide, water. Examples include chromium oxide.

  Of these hydrophobized powders, particularly when hydrophobized microparticles titanium dioxide and hydrophobized microparticles zinc oxide are blended together, significant emulsification and coalescence of emulsified particles may easily occur. As is known, in the oil-in-water skin external preparation according to the present invention, the dispersion stability of the powder can be stabilized by blending the polyglycerol derivative having the specific structure and the block alkylene oxide derivative having the specific structure together. Property and emulsion stability can be remarkably improved. Therefore, the present invention is particularly useful when the hydrophobized powder includes hydrophobized fine particles of titanium dioxide and hydrophobized fine particles of zinc oxide.

  As a compounding quantity of the hydrophobization treatment powder in the oil-in-water type skin external preparation of this invention, 0.1-20 mass% is preferable with respect to the composition whole quantity. If it is less than 0.1% by mass, the effect of the blending is not sufficient, and if it exceeds 20% by mass, the emulsion stability may be deteriorated.

Dibenzoylmethane compound The dibenzoylmethane compound used in the oil-in-water type external preparation for skin according to the present invention is not particularly limited as long as it contains a dibenzoylmethane moiety in its structure. As the dibenzoylmethane-based compound, 4-tert-butyl-4′-methoxydibenzoylmethane is particularly preferable from the viewpoint of ultraviolet absorption ability and safety.
4-tert-butyl-4′-methoxydibenzoylmethane is a known UV absorber in the UV-A region, and there are many commercially available products. For example, PARSOL 1789 commercially available from DSM Nutritional Products may be used in the present invention.

  As a compounding quantity of the dibenzoylmethane type compound in the oil-in-water type skin external preparation of this invention, 0.01-10 mass% is preferable with respect to the composition whole quantity, Most preferably, it is 0.05-5 mass%. When the amount is less than 0.01% by mass, the UV protection effect is insufficient, and when it exceeds 10% by mass, the color may change over time.

  When the hydrophobized powder is blended in the oil-in-water type skin external preparation of the present invention, first, the hydrophobized powder, the polyglycerin derivative, and the dibenzoylmethane series are contained in the oil constituting the oil phase. The compound is blended in advance, and the powder is finely pulverized by a wet disperser having a high crushing force such as a bead mill to obtain a powder dispersion. Next, the obtained powder dispersion is mixed and emulsified with a homomixer and an aqueous phase in which the block-type alkylene oxide derivative having the specific structure is blended in advance. At this time, if there are powder particles having a particle size larger than the emulsified particles to be produced, a part of the powder comes out of the oil phase by the homomixer treatment and forms an aggregate. The diameter needs to be smaller than that of the oil phase.For example, when using a bead mill, the particle size of the crushed powder is made sufficiently small by increasing the number of passes of the dispersion to the mill, which is smaller than the emulsified particle size. A sufficiently small crushed powder can be obtained.

Thickener having salt resistance such as succinoglycan In the oil-in-water type external preparation for skin according to the present invention, a thickener having salt resistance, particularly succinoglycan, xanthan gum or acrylamide, is added to the emulsified oil over time. The stability against drop settling and creaming, as well as the stability against agglomeration of the powder is improved. For example, when a general thickener such as polyacrylic acid is used, a salt that elutes gradually from the inorganic powder fine particles into the aqueous phase acts on the thickener to reduce the viscosity. May end up. On the other hand, when a thickener with excellent salt resistance such as succinoglycan is used, it is not affected by the salt eluted from the inorganic powder. It is thought to prevent sedimentation of the emulsified particles. As a compounding quantity of the thickener which has such salt tolerance, 0.1-1 mass% is preferable with respect to the composition whole quantity. When the amount is less than 0.1% by mass, the effect of the blending is not sufficient, and when it exceeds 1% by mass, the feeling of use may be deteriorated such as the occurrence of warping.

  Further, as the thickener having salt resistance, it is particularly preferable to use succinoglycan because it has a large retention value against a change in temperature and has a large yield value. It has excellent usability effects such as Succinoglycan is a kind of polysaccharide derived from microorganisms. More specifically, in addition to saccharide units derived from galactose and glucose, succinic acid and pyruvic acid, acetic acid as an optional component, or of these acids It means a polysaccharide derived from a microorganism containing a unit derived from a salt.

  More specifically, succinoglycan can optionally include galactose units: 1, glucose units: 7, succinic acid units: 0.8 and pyruvic acid units: 1 having the following structural formula with an average molecular weight of about 6 million: It is a water-soluble polymer represented by the following structural formula that may contain an acetic acid unit as a component.

（式中、Ｇｌｕｃはグルコース単位を、Ｇａｌａｃはガラクトース単位を表す。また．括弧内の表示は糖単位同士の結合様式を表す。例えば（β１，４）は，β１−４結合を表す。）

(In the formula, Gluc represents a glucose unit, and Galac represents a galactose unit. Also, the indication in parentheses represents a binding mode between sugar units. For example, (β1, 4) represents a β1-4 bond.)

  Examples of the microorganisms that supply the succinoglycan include bacteria belonging to the genus Pseudomonas, Rhizobium, Alkaligenes, or Agrobacterium. Among these bacteria, Agrobacterium tumefaciens I-736, which is a bacterium belonging to the genus Agrobacterium, was deposited with the Collection Organization of the Parties to Microbial Cultures (CNCM) on March 1, 1988 in accordance with the Budapest Treaty. Publicly available at ] Is particularly preferred as a source of succinoglycan.

  Succinoglycan can be produced by culturing these microorganisms in a medium. More specifically, carbon sources such as glucose, sucrose, and starch hydrolysates; organic nitrogen sources such as casein, caseinate, vegetable powder, yeast extract, and corn steep liquor (CSL); metal sulfates and phosphates It can be produced by culturing the above microorganisms in a medium containing inorganic salts such as salts and carbonates and optional trace elements.

  Of course, the succinoglycan produced as described above can be blended as it is in the oil-in-water type skin external preparation according to the present invention, as required, such as acid decomposition, alkali decomposition, enzyme decomposition, ultrasonic treatment, etc. The decomposition treatment product can be blended in the same manner. Further, when succinoglycan is blended as a thickener, the powder may be distorted when the composition is applied to the skin. In order to improve this, it is particularly suitable to use dynamite glycerin as a moisturizing agent, and the feeling of use can be improved by eliminating the distortion of the powder.

An emulsification aid such as carboxymethylcellulose is also selected from carboxymethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose and gelatin to further improve the temperature stability and dispersion stability of the oil-in-water external preparation according to the present invention. It is preferable to blend 0.1 to 1.0% by mass of one or two or more of them as an emulsification aid. If it is less than 0.1% by mass, the effect of the blending is not sufficient, and if it exceeds 1.0% by mass, the feeling of use tends to be poor.

Oil content Although it does not specifically limit as an oil content mix | blended with the oil-in-water type skin external preparation concerning this invention, For example, a silicone oil or polar oil can be used conveniently. Examples of the silicone oil include dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, decamethylpolysiloxane, dodecamethylpolysiloxane, tetramethyltetrahydrogenpolysiloxane, cyclotetradimethylsiloxane, and cyclopentadimethylsiloxane. Examples thereof include linear or cyclic polysiloxane.

  Examples of the polar oil include synthetic, natural ester oil, and a specific ultraviolet absorber. Synthetic ester oils include, for example, isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyl decyl dimethyloctanoate, cetyl lactate, lactic acid Myristyl, lanolin acetate, isocetyl stearate, isocetyl isostearate, cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexanoate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, Diisostearyl malate, glycerin di-2-heptylundecanoate, tri-2-ethylhexanoate trimethylolpropane, triisostearate Trimethylol propane acid, penta-2-ethylhexanoic acid pentane erythritol, glycerin tri-2-ethylhexanoate, trimethylol propane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glyceryl trimyristate , Tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleyl oleate, cetostearyl alcohol, acetoglyceride, 2-heptylundecyl palmitate, diisobutyl adipate, N-lauroyl-L-glutamic acid-2-octyldodecyl , Di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyl adipate Examples include rudecyl, diisopropyl sebacate, 2-ethylhexyl succinate, ethyl acetate, butyl acetate, amyl acetate, and triethyl citrate. Examples of natural ester oils include avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, sasanca oil, castor oil, Flaxseed oil, safflower oil, cottonseed oil, eno oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, cinnagiri oil, jojoba oil, germ oil, triglycerin, trioctanoic acid glycerin, triisopalmitic acid glycerin Can be mentioned. Examples of ultraviolet absorbers that are polar oils include octyl cinnamate, ethyl-4-isopropyl cinnamate, ethyl-2,4-diisopropyl cinnamate, methyl-2,4-diisopropyl cinnamate, propyl-p-methoxycinnamate. , Isopropyl-p-methoxycinnamate, isoamyl-p-methoxycinnamate, octylmethoxycinnamate, 2-ethoxyethyl-p-methoxycinnamate, cyclohexyl-p-methoxycinnamate, ethyl-α-cyano-β-phenyl Cinnamic acid-based ultraviolet absorbers such as cinnamate and 2-ethylhexyl-α-cyano-β-phenylcinnamate are exemplified.

  Moreover, as the oil component to be blended in the oil-in-water type skin external preparation according to the present invention, it is possible to blend other oil components used in general cosmetics in addition to the polar oil and silicone oil, for example, Liquid paraffin, squalane, isoparaffin, ozokerite, pristane, ceresin, petrolatum, microcrystalline wax, paraffin wax, and other liquid, semi-solid (grease-like), or nonpolar oils such as solid hydrocarbons can also be blended. The total oil content in the oil-in-water type external skin preparation of the present invention is not particularly limited, but is about 5 to 60% by mass, preferably 10 to 35% by mass with respect to the total amount of the composition. %. When the total oil content is less than about 5% by mass, it is difficult to improve the usability when used as an external preparation. On the other hand, when it exceeds 60% by mass, the emulsification stability over time is increased. It is often inferior.

  In the oil-in-water type skin external preparation of the present invention, various components that are usually used in cosmetics, for example, ultraviolet absorbers (other than the dibenzoylmethane compounds) and humectants, as long as the effects of the present invention are not impaired. , PH adjusters, neutralizers, antioxidants, antiseptics, antibacterial agents, drugs, extracts, fragrances, pigments and the like can be blended. Examples of the humectant include polyhydric alcohols such as glycerin, diethylene glycol, butylene glycol, and polyethylene glycol, proteins such as amino acids, nucleic acids, collagen, and elastin, and mucopolysaccharides such as hyaluronic acid and chondroitin sulfate.

  As the ultraviolet absorber, in addition to the dibenzoylmethane compound, which is an essential component of the present invention, for example, benzoic acid ultraviolet absorbers such as paraaminobenzoic acid, anthranilic acid ultraviolet absorbers such as methyl anthranilate, Salicylic acid UV absorbers such as octyl salicylate, phenyl salicylate, homomethyl salicylate, isopropyl paramethoxycinnamate, octyl paramethoxycinnamate, 2-ethylhexyl paramethoxycinnamate, mono-2-ethyl diparamethoxycinnamate Cinnamate UV absorbers such as glyceryl hexanoate, [4-bis (trimethylsiloxy) methylsilyl-3-methylbutyl] -3,4,5, -trimethoxycinnamate, 2,4-dihydroxybenzophenone, 2 -Hydroxy-4-methoxybenzophenone Benzophenone ultraviolet absorbers such as 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, sodium 2-hydroxy-4-methoxybenzophenone-5-sulfonate, urocanic acid, ethyl urocanate, 2-phenyl-5-methyl Benzoxazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, bis (resorcinyl) triazine, 2,4-bis [{4- (2-ethylhexoxy) -2-hydroxy}- Phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine and the like.

  Examples of the pH adjuster include lactic acid, citric acid, glycolic acid, succinic acid, tartaric acid, dl-malic acid, potassium carbonate, sodium hydrogen carbonate, ammonium hydrogen carbonate and the like. Examples of the antioxidant include ascorbic acid, α-tocopherol, dibutylhydroxytoluene, butylhydroxyanisole and the like. Examples of preservatives and antibacterial agents include paraoxybenzoic acid esters, phenoxyethanol, benzoic acid, salicylic acid, carboxylic acid, sorbic acid, parachlormetacresol, hexachlorophene, benzalkonium chloride, chlorhexidine chloride, trichlorocarbanilide, and photosensitizers. Can be mentioned.

  The use of the oil-in-water type external preparation for skin according to the present invention is not particularly limited. For example, lotion, emulsion, cream, foundation, lipstick, cleansing foam, shampoo, hair rinse, lip balm, hair spray, mousse It can be applied to various products such as sunscreen or tanning cream, eyeliner, mascara, hair or nail care, cream, body makeup preparation and the like. Moreover, among these, it can use suitably as sunscreen cosmetics especially.

The present invention will be described in more detail with reference to examples of the present invention, but the present invention is not limited thereto.
Initially, the manufacturing method of the polyglycerol derivative used for this invention is demonstrated.

Synthesis Example 1 Polyoxybutylene (25 mol) methyltriglyceryl ether

1) Ketalization reaction In a four-necked flask, 240 g of triglycerin (“Triglycerin> 80%” manufactured by SOLVAY: purity 83%), 240 g of 2,2-dimethoxypropane, and 1.5 mg of paratoluenesulfonic acid were charged. After substitution with nitrogen gas, the reaction was carried out at 50 ° C. for 3 hours. After the reaction, unreacted volatile components were distilled off by heating under a nitrogen stream, and acetic acid was added to adjust to pH 7 to obtain a triglycerin diketalized product. The purity of triglycerin was measured under the above-mentioned gas chromatography analysis conditions. Also, when comparing the IR analysis of triglycerol with the product of the raw material, the product is smaller peak of hydroxyl group in the vicinity of 3500 cm ^{-1, 2960 cm} -1 ^{instead, 2870cm -1, 1460cm -1, 1380cm Since} the peak near ⁻¹ appeared, it was confirmed that the target substance was obtained.

2) Oxybutylene reaction 320 g of triglycerin diketalization product and 12 g of potassium hydroxide were charged into an autoclave, the air in the autoclave was replaced with dry nitrogen, and the catalyst was completely dissolved at 140 ° C. with stirring. Next, 1800 g of butylene oxide was dropped with a dropping device and stirred for 2 hours. Next, after charging 168.3 g of potassium hydroxide and replacing the system with dry nitrogen, 151.5 g of methyl chloride was injected at a temperature of 80 to 130 ° C. and reacted for 5 hours. Thereafter, the reaction composition was taken out from the autoclave, neutralized with hydrochloric acid to pH 6 to 7, and treated at 100 ° C. for 1 hour under reduced pressure to remove the contained water. Further, filtration was carried out to remove the salt produced after the treatment, and an oxybutylenated triglycerin diketalized product was obtained.

3) Deketalization reaction In a four-necked flask, 2134 g of an oxybutylene triglycerin diketalized product, 50 g of 36% hydrochloric acid, and 100 g of water were charged, and a deketal reaction was performed at 80 ° C. for 2 hours in a sealed state. Next, the solution was adjusted to pH 6-7 with an aqueous potassium hydroxide solution and treated at 100 ° C. for 1 hour under reduced pressure in order to remove the contained water. Further, filtration was performed to remove the salt produced after the treatment, and polyoxybutylene (25 mol) methyltriglyceryl ether was obtained.

In addition, when the GPC analysis was performed about the product obtained by the above, the molecular weight of the main peak was 1939. The analysis conditions are as follows.
Analytical instrument: SHODEX GPC SYSTEM-11 (manufactured by Showa Denko)
Standard substance: Polyethylene glycol Sample size: 10% x 100 x 0.001 mL
Eluent: THF
Flow rate: 1.0 mL / min
Column: SHODEX KF804L (manufactured by Showa Denko)
Column size: I.D. D. 8mm x 30cm x 3
Column temperature: 40 ° C
Detector: RI x 8
Also, verify that since when compared to IR analysis of oxybutylene of triglycerol di ketal compound and product, the product is hydroxyl peak around 3500 cm ^-1 is large, and the target substance is obtained did.

Synthesis Example 2 Polyoxybutylene (25 mol) methyltriglyceryl ether Among the procedures of Synthesis Example 1, 1) Synthesis was performed by changing the ketalization reaction as follows, and polyoxybutylene (25 mol) methyltriglyceryl. Ether was obtained. Other conditions were the same as in Synthesis Example 1.

1) Ketalization reaction In a four-necked flask, 240 g of triglycerin (“Triglycerin> 80%” manufactured by SOLVAY: 83% purity), 290 g of acetone, and 4 mg of paratoluenesulfonic acid were charged, and the reaction system was replaced with nitrogen gas at 70 ° C. For 8 hours. After the reaction, unreacted volatile components were distilled off by heating under a nitrogen stream, and acetic acid was added to adjust to pH 7 to obtain a triglycerin diketalized product.

Synthesis Example 3 Polyoxybutylene (50 mol) triglyceryl ether

  In the procedure of Synthesis Example 1, 2) oxybutylene reaction was changed as follows, and synthesis was performed to obtain polyoxybutylene (50 mol) triglyceryl ether. Other conditions were the same as in Synthesis Example 1.

2) Oxybutylene reaction 320 g of triglycerin diketalization product and 20 g of potassium hydroxide were charged into an autoclave, the air in the autoclave was replaced with dry nitrogen, and the catalyst was completely dissolved at 140 ° C. with stirring. Next, 3600 g of butylene oxide was dropped with a dropping device and stirred for 2 hours. Thereafter, the reaction composition was taken out from the autoclave, neutralized with hydrochloric acid to pH 6 to 7, and treated at 100 ° C. for 1 hour under reduced pressure to remove the contained water. Further, filtration was carried out to remove the salt produced after the treatment, and an oxybutylenated triglycerin diketalized product was obtained.

3) Deketalization reaction 3920 g of oxybutylenated triglycerin diketalized product, 70 g of 36% hydrochloric acid and 200 g of water were charged in a four-necked flask, and the deketal reaction was carried out at 80 ° C. for 3 hours in a sealed state. Next, the solution was adjusted to pH 6-7 with an aqueous potassium hydroxide solution and treated at 100 ° C. for 1 hour under reduced pressure in order to remove the contained water. Further, filtration was performed to remove the salt produced after the treatment, and polyoxybutylene (50 mol) triglyceryl ether was obtained.

Next, a method for producing the alkylene oxide derivative used in the present invention will be described.
Alkylene oxide derivatives
Synthesis Example 4 Polyoxyethylene (10 mol) Polyoxypropylene (10 mol) Dimethyl ether (Block polymer)
CH ₃ O (EO) ₁₀ (PO) ₁₀ CH ₃
76 g of propylene glycol and 3.1 g of potassium hydroxide as a catalyst were charged into an autoclave. After the air in the autoclave was replaced with dry nitrogen, the catalyst was completely dissolved at 140 ° C. with stirring. Next, 522 g of propylene oxide was dropped with a dropping device and stirred for 2 hours. Subsequently, 440 g of ethylene oxide was dropped with a dropping device and stirred for 2 hours. Next, 224 g of potassium hydroxide was charged and the inside of the system was replaced with dry nitrogen, and then 188 g of methyl chloride was injected at a temperature of 80 to 130 ° C. and reacted for 5 hours. Thereafter, the reaction composition was taken out from the autoclave, neutralized with hydrochloric acid to pH 6 to 7, and treated at a reduced pressure of -0.095 MPa (50 mmHg) at 100 ° C for 1 hour in order to remove the contained water. Further, filtration was performed to remove the salt produced after the treatment, and the block type alkylene oxide derivative was obtained.
Samples that were sampled and reacted before reacting with methyl chloride had a hydroxyl value of 110, the resulting compound had a hydroxyl value of 0.3, and the ratio of the number of hydrogen atoms to the number of terminal methyl groups was 0.003, indicating that hydrogen was almost completely removed. An atom is converted to a methyl group.

Synthesis Example 5 Polyoxyethylene (10 mol) Polyoxypropylene (10 mol) Dimethyl ether (Random polymer)
CH ₃ O [(EO) ₁₀ / (PO) ₁₀ ] CH ₃
76 g of propylene glycol and 3.1 g of potassium hydroxide as a catalyst were charged into an autoclave. After the air in the autoclave was replaced with dry nitrogen, the catalyst was completely dissolved at 140 ° C. with stirring. Next, a mixture of 440 g of ethylene oxide and 522 g of propylene oxide was dropped with a dropping device and stirred for 2 hours. Next, 224 g of potassium hydroxide was charged and the inside of the system was replaced with dry nitrogen, and then 188 g of methyl chloride was injected at a temperature of 80 to 130 ° C. and reacted for 5 hours. Thereafter, the reaction composition was taken out from the autoclave, neutralized with hydrochloric acid to pH 6 to 7, and treated at a reduced pressure of -0.095 MPa (50 mmHg) at 100 ° C for 1 hour in order to remove the contained water. Further, filtration was performed to remove the salt generated after the treatment, and the random alkylene oxide derivative was obtained.
Samples that were sampled and reacted before the reaction with methyl chloride had a hydroxyl value of 107, the resulting compound had a hydroxyl value of 0.4, and the ratio of the number of hydrogen atoms to the number of terminal methyl groups was 0.004. An atom is converted to a methyl group.

  The present inventors first prepared various polyglycerol derivatives and block-type alkylene oxide derivatives according to the above synthesis examples, and formulated an oil-in-water skin external preparation (tanning) containing the polyglycerol derivative and the block-type alkylene oxide derivative. Comparison was made between an oil-in-water type external preparation for skin and a conventional dispersing agent. Table 1 below shows the composition of the oil-in-water external preparation for each test example and the evaluation results. In addition, all compounding quantities are the mass%. The evaluation criteria are as follows.

(1): “Moist feeling after use”
About the presence or absence of a moist feeling after using the oil-in-water type skin external preparation of each Example and a comparative example, the actual use test was implemented by ten professional panelists. The evaluation criteria are as follows.
<Evaluation criteria>
◎… 8 or more panelists recognized that there was a moist feeling after use.
○… 6 or more and less than 8 panelists recognized that there was a moist feeling after use.
Δ: 3 or more and less than 6 panelists recognized that there was a moist feeling after use.
X: Less than 3 panelists recognized that there was a moist feeling after use.

(2): “No stickiness after use”
About the presence or absence of the stickiness after using the oil-in-water type skin external preparation of each Example and a comparative example, the actual use test was implemented by ten professional panelists. The evaluation criteria are as follows.
<Evaluation criteria>
◎… 8 or more panelists recognized that there was no stickiness after use.
○… 6 or more and less than 8 panelists recognized that there was no stickiness after use.
Δ: 3 or more and less than 6 panelists recognized that there was no stickiness after use.
X: Less than 3 panelists recognized that there was no stickiness after use.

(3) Dispersion stability of powder The oil-in-water type external preparation for skin of each Example and Comparative Example was placed in a 50 ml sample tube (diameter 3 cm) and rotated at a speed of 45 rpm at room temperature for 4 hours to aggregate the powder. The degree was evaluated visually. The evaluation criteria are as follows.
<Evaluation criteria>
◯: No powder aggregate was visually observed.
Δ: Some powder agglomerates were visually observed.
X: A considerable amount of powder aggregate was visually observed.

(4) Emulsification stability The oil-in-water type skin external preparation of each Example and Comparative Example was put into a 50 ml sample tube (diameter 3 cm), rotated at room temperature for 4 hours at a speed of 45 rpm, and the emulsion stability was measured with a microscope. evaluated. The evaluation criteria are as follows.
<Evaluation criteria>
○: No coalescence due to emulsified particles was observed with a microscope.
(Triangle | delta): The coalescence by some emulsified particles was recognized with the microscope.
X: Coalescence by emulsified particles was observed with a microscope.

Ｌ_０：基準品のＬ値、ａ_０：基準品のａ値、ｂ_０：基準品のｂ値、Ｌ_ｘ：実施例及び比較例の水中油型皮膚外用剤のＬ値、ａ_ｘ：実施例及び比較例の水中油型皮膚外用剤のａ値、ｂ_ｘ：実施例及び比較例の水中油型皮膚外用剤のｂ値
評価基準は以下の通りである。
＜評価基準＞
◎：変色抑制効果が非常に高い。（ΔＥ＞９）
○：変色抑制効果が高い。（６＜ΔＥ≦９）
△：あまり変色抑制効果が高くない。（３＜ΔＥ≦６）
×：全く変色抑制効果がない。（ΔＥ≦３） (5) Discoloration suppression effect (color difference measurement)
The oil-in-water type skin external preparations of each Example and Comparative Example were placed in a 50 ml sample tube (diameter 3 cm), and color difference measurement was performed after 1 month of standing at 50 ° C. The method was carried out using a color difference meter (manufactured by Minolta Co., Ltd., spectrocolorimeter CM-2002), and the discoloration suppressing effect was determined based on the color difference (ΔE) from the reference product calculated by the following calculation formula.

L ₀ : L value of the reference product, a ₀ : a value of the reference product, b ₀ : b value of the reference product, L _x : L value of the oil-in-water type skin external preparation of Examples and Comparative Examples, a _x : Implementation A value of the oil-in-water type skin external preparation of Examples and Comparative Examples, b _x : Evaluation criteria for the b value of the oil-in-water type skin external preparation of Examples and Comparative Examples are as follows.
<Evaluation criteria>
(Double-circle): The discoloration suppression effect is very high. (ΔE> 9)
○: High discoloration suppressing effect. (6 <ΔE ≦ 9)
(Triangle | delta): The discoloration suppression effect is not so high. (3 <ΔE ≦ 6)
X: No discoloration suppressing effect at all. (ΔE ≦ 3)

(6) Discoloration suppression effect (visual judgment)
The oil-in-water type skin external preparation of each Example and the comparative example was put into a 50 ml sample tube (diameter 3 cm), and the appearance color change was evaluated visually by a professional judge after leaving at 50 ° C. for one month. The evaluation criteria are as follows.
<Evaluation criteria>
A: Almost no change in appearance color is observed.
○: Slight change in appearance color is observed.
Δ: Change in appearance color is observed.
X: Appearance color has changed.

  As is clear from Table 1 above, in the system of an oil-in-water emulsion composition in which hydrophobized fine particle titanium dioxide, hydrophobized titanium dioxide, and 4-tert-butyl-4′-methoxydibenzoylmethane are blended together. In the case of using sorbitan sesquiisostearate and trimethylsiloxysilicic acid, which have been widely used as dispersants in the past, the dispersion stability and emulsification stability of the hydrophobized powder are inferior, and significant discoloration over time has occurred. It turns out that it has arisen (Comparative Examples 1-1, 1-2).

  On the other hand, when a polyglycerin derivative having a specific structure (polyoxybutylene (25 mol) methyltriglyceryl ether or the like) is blended together with a block-type alkylene oxide derivative, the two hydrophobized powders and 4- Despite the combination of tert-butyl-4'-methoxydibenzoylmethane, it is excellent in use feeling, powder dispersion stability, and emulsion stability, and further discoloration over time is suppressed. Thus, it was revealed that the appearance stability was excellent (Examples 1-1 to 1-4).

  Subsequently, in order to further examine the suitability of the polyglycerin derivative, the present inventors prepared various polyglycerin derivatives in accordance with the above synthesis examples, and the oil-in-water type skin external preparation formulated with the various polyglycerin derivatives. Evaluation was performed in the same manner as in the test. Table 2 below shows the composition and evaluation results of the oil-in-water type skin external preparations of each Example and Comparative Example.

  As is clear from Table 2 above, the oil-in-water type skin external preparation using a polyglycerin derivative having a polyoxybutylene group terminated with hydrogen or a butyl group is composed of the above-mentioned two hydrophobized powders and 4-tert-butyl. -4'-Methoxydibenzoylmethane is blended together, but the feeling of use, dispersion stability of the powder, and emulsion stability are improved, and the discoloration suppressing effect is very excellent. (Examples 1-5 and 1-6). Furthermore, even when a polyglycerin derivative having an addition mole number of polyoxybutylene of 10 moles or 150 moles was used, the same excellent use feeling, powder dispersibility, emulsion stability, and discoloration suppression effect were exhibited. (Examples 1-7 and 1-8).

  In contrast, when unmodified triglycerin and methyl group-modified triglycerin were used, aggregation of the hydrophobized powder, coalescence of emulsified particles, and discoloration were observed (Comparative Example 1-3). 1-4). In addition, when using a polyglycerin derivative in which the terminal of the polyoxybutylene group is a hexyl group and a polyglycerin derivative having a polyoxybutylene addition mole number of 250 mol, the powder dispersibility and the emulsion stability are similarly obtained. (Comparative Examples 1-5 and 1-6). Furthermore, even when a polyglycerin derivative added with a polyoxybutylene group without protecting the terminal hydroxyl group by the ketalization reaction is used, excellent powder dispersibility, emulsion stability, and discoloration inhibiting effect can be obtained. (Comparative Example 1-7).

  Subsequently, in order to further examine the suitability of the alkylene oxide derivative to be blended with the polyglycerin derivative, the present inventors prepared various alkylene oxide derivatives according to the above synthesis examples, and oil-in-water type blended with various alkylene oxide derivatives. The external preparation for skin was evaluated in the same manner as in the above test. Table 3 below shows the composition and evaluation results of the oil-in-water type skin external preparations of Examples and Comparative Examples.

As apparent from Table 3 above, together with the polyglycerin derivative, a block-type alkylene oxide derivative having a structure represented by the general formula (2) as an emulsifier (for example, CH ₃ O (EO) ₂₅ (PO) ₃₀ CH ₃ block polymer, etc. In the oil-in-water type skin external preparation formulated with), excellent evaluation results were obtained not only in the feeling of use but also in the dispersion stability of the powder, the emulsion stability, and the discoloration inhibiting effect (Examples) 1-9, 1-10).

  On the other hand, when an alkylene oxide derivative containing only an oxyethylene group or oxypropylene was used, the feeling of use was inferior, and the dispersion stability and emulsification stability of the powder were also reduced (Comparative Example 1). -8, 1-9). Further, when random type alkylene oxide derivatives and alkylene oxide derivatives having a molecular weight of less than 1000 were used, they were inferior in terms of powder dispersion stability and emulsion stability (Comparative Examples 1-10, 1- 11). Furthermore, when an alkylene oxide derivative having an oxyethylene group of 80 mol or more or a hydrogen group at both ends is used, it is not preferable in terms of use feeling (Comparative Examples 1-12 and 1-13). When an alkylene oxide derivative in which is a hydrocarbon group having 6 carbon atoms was used, it was not sufficient in terms of dispersion stability and emulsion stability (Comparative Example 1-14).

Formulation of thickener having salt resistance In addition, in order to examine the thickening component to be blended in the oil-in-water type skin external preparation, the present inventors have formulated an oil-in-water type skin external formulation formulated with various thickeners. Evaluation was performed in the same manner as in the above test. Table 4 below shows the composition and evaluation results of the oil-in-water type skin external preparations of Examples and Comparative Examples.

  From Table 4 above, when blending succinoglycan, xanthan gum and acrylamide as a thickener component together with a polyglycerin derivative and a block-type alkylene oxide derivative, it is particularly excellent in powder dispersion stability and emulsion stability. In contrast to (Examples 1-11 to 1-13), when polyacrylic acid, which is widely used as a general thickener, is blended as a thickener, both dispersion stability and emulsion stability are poor. (Example 1-14).

  In addition, about the said result, a salt elutes in time from the inorganic powder fine particle (titanium oxide) in an oil phase into a water phase, for example like polyacrylic acid used in Example 1-14 When a normal thickener is used, it is considered that the viscosity of the system has been lowered because this salt has an adverse effect on the thickener. On the other hand, when a thickener excellent in salt resistance such as succinoglycan blended in Examples 1-11 to 13 is used, it is not affected by the salt eluted from the inorganic powder. For this reason, it is considered that aggregation of powder and sedimentation of emulsified particles are prevented over a long period of time.

Hereinafter, the present invention will be described in more detail with reference to other examples of the oil-in-water type external preparation for skin according to the present invention, but the present invention is not limited thereto.
Example 2-1: Suncut oil-in-water emulsion (% by mass)
(1) Hydrophobized fine particle titanium dioxide 3
(2) Hydrophobized acid microparticle zinc 7
(3) Polyoxybutylene (42 mol) triglyceryl ether 2.5
(4) Decamethylpentacyclosiloxane 10
(5) 4-tert-butyl-4′-methoxydibenzoylmethane 1
(6) Octyl paramethoxycinnamate 5
(7) Tri-2-ethylhexanoic acid glycerin 3
(8) CH ₃ O (EO) ₃₅ (PO) ₄₀ CH ₃ (Block polymer) 3
(9) 1,3-butylene glycol 8
(10) Succinoglycan 0.2
(11) Carboxymethylcellulose 0.25
(12) Ethanol 3
(13) Residual ion exchange water
Production methods (1) to (7) were mixed, dispersed and crushed by a bead mill, and then added to a water phase in which (8) to (13) were dissolved while applying a homomixer.

Example 2-2: Suncut oil-in-water emulsion (% by mass)
(1) Hydrophobized fine particle titanium dioxide 12
(2) Polyoxybutylene (28 mol) triglyceryl ether 3
(3) Decamethylpentacyclosiloxane 8
(4) 4-tert-butyl-4′-methoxydibenzoylmethane 1
(5) Octyl paramethoxycinnamate 7
(6) Tri-2-ethylhexanoic acid glycerin 5
(7) CH ₃ O (EO) ₃₅ (PO) ₄₀ CH ₃ (Block polymer) 2.5
(8) Dynamite glycerin 6
(9) Succinoglycan 0.3
(10) Carboxymethylcellulose 0.25
(11) Ethanol 2.5
(12) Residual ion exchange water
Production methods (1) to (6) were mixed, dispersed and crushed with a bead mill, and then added to a water phase in which (7) to (12) were dissolved while applying a homomixer.

Example 2-3: Sun-cut oil-in-water emulsion (% by mass)
(1) Hydrophobized fine particle zinc oxide 15
(2) Polyoxybutylene (56 mol) triglyceryl ether 3
(3) Decamethylpentacyclosiloxane 12
(4) 4-tert-butyl-4′-methoxydibenzoylmethane 1
(5) Octyl paramethoxycinnamate 7
(6) Tri-2-ethylhexanoic acid glycerin 4
(7) CH ₃ O (EO) ₃₅ (PO) ₄₀ CH ₃ (Block polymer) 3.4
(8) 1,3-butylene glycol 8
(9) Succinoglycan 0.3
(10) Carboxymethylcellulose 0.2
(11) Ethanol 2
(12) Residual ion exchange water
Production methods (1) to (6) were mixed, dispersed and crushed with a bead mill, and then added to a water phase in which (7) to (12) were dissolved while applying a homomixer.

Example 2-4: Oil-in-water emulsion foundation (mass%)
(1) Hydrophobized fine particle titanium dioxide 7
(2) Hydrophobized fine particle zinc oxide 9
(3) Hydrophobized yellow iron oxide 0.8
(4) Hydrophobized black iron oxide 0.16
(5) Hydrophobized Bengala 0.36
(6) Polyoxybutylene (56 mol) methyltriglyceryl ether 3
(7) Decamethylpentacyclosiloxane 10
(8) 4-tert-butyl-4′-methoxydibenzoylmethane 1
(9) Octyl paramethoxycinnamate 5
(10) Octyldodecyl myristate 3
(11) CH ₃ O (EO) ₃₅ (PO) ₄₀ CH ₃ (Block polymer) 3
(12) Dynamite glycerin 4
(13) Xanthan gum 0.3
(14) Carboxymethylcellulose 0.3
(15) Ethanol 5
(16) Residual ion exchange water
Production methods (1) to (10) were mixed, dispersed and crushed with a bead mill, and then added to a water phase in which (11) to (16) were dissolved while applying a homomixer.

Example 2-5: UV protection whitening serum (mass%)
(1) Hydrophobized fine particle titanium dioxide (silicone treatment) 6
(2) Hydrophobized fine particles of zinc oxide 8
(3) Polyoxybutylene (42 mol) methyltriglyceryl ether 2.8
(4) Decamethylpentacyclosiloxane 10
(5) 4-tert-butyl-4′-methoxydibenzoylmethane 1
(6) Octyl paramethoxycinnamate 5
(7) Isopropyl palmitate 4
_{(8) CH 3 O (EO} ) 35 (PO) 40 CH 3 ( block polymer) 3
(9) Dynamite Glycerin 5
(10) Succinoglucan 0.3
(11) Carboxymethylcellulose 0.3
(12) Ethanol 4
(13) Citric acid appropriate amount (14) Sodium citrate appropriate amount (15) Ascorbic acid glycoside 2
(16) Caustic potash
(17) Residual ion exchange water
Production methods (1) to (7) were mixed, dispersed and crushed by a bead mill, and then added to a water phase in which (8) to (17) were dissolved while applying a homomixer.

  The oil-in-water type skin external preparations of the above Examples were excellent in feeling of use, powder dispersibility, emulsion stability, and discoloration suppressing effect.

Claims (6)

Hydrophobized powder,
A dibenzoylmethane compound,
A polyglycerin derivative represented by the following general formula (1);
An oil-in-water type skin external preparation characterized by containing a block-type alkylene oxide derivative represented by the following general formula (2).

(In the formula, m + 2 represents the average degree of polymerization of polyglycerol, 1 ≦ m ≦ 4, R ¹ is a hydrocarbon group or hydrogen atom having 1 to 4 carbon atoms, AO is an oxyalkylene group having 3 to 4 carbon atoms, n is the average added mole number of the oxyalkylene group, and 1 ≦ m × n ≦ 200.
R ¹ O— (AO) _m (EO) _n —R ² (2)
(In the formula, AO is an oxyalkylene group having 3 to 4 carbon atoms, EO is an oxyethylene group, m and n are average addition moles of the oxyalkylene group and oxyethylene group, respectively, 1 ≦ m ≦ 70, 1 ≦ n ≦ 70 The oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group are added in a block form, and the ratio of the oxyethylene group to the total of the oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group is 20 to 80 wt% .R ¹ and ^{R 2} are identical or different and have good 1 to 4 carbon atoms hydrocarbon group or a hydrogen atom, the number of hydrogen atoms to the number of hydrocarbon groups of ^{R 1} and ^{R 2} The ratio is 0.15 or less.)   The oil-in-water type skin external preparation according to claim 1, wherein the hydrophobized powder contains hydrophobized fine particle titanium dioxide and hydrophobized fine particle zinc oxide.   The oil-in-water type skin external preparation according to claim 1 or 2, wherein the dibenzoylmethane compound is 4-tert-butyl-4'-methoxydibenzoylmethane. .   The oil-in-water type external skin preparation according to any one of claims 1 to 3, further comprising one or more selected from succinoglycan, xanthan gum and acrylamide. Agent.   The oil-in-water type external preparation for skin according to any one of claims 1 to 4, further comprising one or more selected from carboxymethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, and gelatin. Type skin external preparation.   A sunscreen cosmetic comprising the oil-in-water type external preparation for skin according to any one of claims 1 to 5.