JPH0577644B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a cosmetic, more specifically, a cosmetic containing fine-particle zinc oxide powder, which has good dispersion stability and has a transparent appearance when applied to the skin. It does not cause white spots and has UV protection effect.
This article relates to excellent cosmetics that also have anti-inflammatory and sterilizing effects.

[Prior art] Powders used in cosmetics have generally had a particle size of about 0.5μ, and titanium oxide, which has the smallest particle size of about 300 to 400Å, is only known. Atsuta (Special Publication No. 47-42502).

[Problems to be solved by the invention] As mentioned above, if the particle size of the blended powder is about 300 to 400 Å or more, when applied to the skin, white spots will be noticeable and it will look unnatural. I can't deny it. For this reason, this whiteness has been a major obstacle when trying to incorporate powder into cosmetics to provide UV protection or give a refreshing feeling to the skin.

In view of the current situation, the present inventors focused on zinc oxide and, as a result of intensive study, discovered that the above-mentioned drawbacks could be solved by making this material into fine particles and blending it into a cosmetic base. This is what we came to do.

[Means for Solving the Problems] That is, the present invention is a cosmetic characterized by containing fine-particle zinc oxide powder.

Hereinafter, the configuration of the present invention will be explained in detail.

The fine particle zinc oxide powder used in the present invention has a particle size of 10~
It is a fine-particle zinc oxide powder with an average particle size of 200 Å (more than 50 Å and less than 100 Å), and can be obtained by mechanical grinding, etc., but it is easy to manufacture and it is difficult to incorporate the obtained fine-particle powder into a cosmetic base. Because of its good dispersibility and uniform particle size, colloidal particles in a hydrosol of zinc sulfate or zinc chloride prepared in an aqueous solution are converted into lipophilic particles with an anionic surfactant, and then flushed with an organic solvent. Particularly preferred is a fine-particle zinc oxide powder obtained by then drying and removing the organic solvent. The particle size of the fine zinc oxide powder obtained through the above colloidal sol (hereinafter referred to as the sol method) is distributed in the range of 10 to 200 Å, generally in the range of 50 to 100 Å, and the average particle size is in the range of more than 50 Å and less than 100 Å. exists in

The sol method will be explained in more detail.

In this method, first, an aqueous sodium carbonate solution is added to an aqueous solution of zinc chloride or zinc sulfate to form a hydrosol. The concentration of the zinc chloride or zinc sulfate aqueous solution is about 0.1 to 1.0 mol, the concentration of the sodium carbonate aqueous solution is about 0.2 to 1.0 mol, and the ratio of the zinc chloride or zinc sulfate aqueous solution to the sodium carbonate aqueous solution is about 1:1 by weight.

Next, an anionic surfactant is added to make the hydrosol lipophilic. The anionic surfactant used is sodium alkylbenzene sulfonate,
Sodium lauryl sulfate, potassium lauryl sulfate, alkyl sulfate triethanolamine ether, funnel oil, sodium dialkyl sulfosuccinate, sodium di2ethylhexyl sulfosuccinate, sodium lauryl polyethylene glycol sulfosuccinate, sodium alkyl ether sulfate, poly Sodium oxyethylene (hereinafter referred to as POE) alkyl sulfate, N-palmitoylaspartate ditriethanolamine, sodium coconut oil fatty acid methyltauride, sodium myristoylmethyltaurate, sodium lauryl methyltauride, sodium lauroyl glutamate, oxidized coconut oil fatty acid glycerin sulfate Sodium, disodium stearoyl glutamate, sodium myristoyl glutamate, POE sodium alkyl phenyl ether sulfate, POE alkyl sulfate triethanolamine, sodium lauroyl sarcosine,
sodium caseinate, sodium palmitate,
Examples include sodium laurate, POE hydrogenated castor oil maleate, and particularly preferred are sodium alkylbenzenesulfonate, sodium lauryl sulfate, potassium lauryl sulfate, and alkyl sulfate triethanolamine ether. The amount of anionic surfactant added varies depending on the ratio of zinc chloride or zinc sulfate to sodium carbonate, but it should generally be selected in the range of 0.05 to 0.15 mol per 1 mol of zinc chloride or zinc sulfate. .

In the sol method according to the present invention, the obtained fine particle zinc oxide powder is adjusted to be either hydrophilic or lipophilic by appropriately selecting the balance between hydrophilicity and lipophilicity of the anionic surfactant. be able to. For example, when blending fine-particle zinc oxide powder into aqueous-based cosmetics, it is recommended to use sodium lauryl sulfate, potassium lauryl sulfate, alkyl sulfate triethanolamine ether, etc. as anionic surfactants to form hydrophilic fine-particle zinc oxide powder. A powder is obtained. Furthermore, when sodium alkylbenzenesulfonate or the like is used as an anionic surfactant, lipophilic fine particle zinc oxide powder can be obtained, which is suitable for blending into oil-based cosmetics.

The lipophilized hydrosol is then flushed with an organic solvent. Any organic solvent may be used as long as it dissolves the anionic surfactant. For example, xylene, toluene, benzene, etc., and a mixed solvent thereof are used. The amount of organic solvent is 0.5 to 0.5 to the hydrosol solution by weight.
Selected within a range of approximately 1.0 times the amount.

The organosol thus obtained is dried to separate fine particles of zinc oxide powder. There are no particular restrictions on the drying method, and any conventional method may be used.

In the present invention, the fine particle zinc oxide powder is 0.5 to 100% by weight of the total amount of the cosmetic, 10% by weight or more from the perspective of UV protection, and 50% by weight from the perspective of providing a refreshing effect on the skin. It is preferable that the above components be blended.

The dosage form of the cosmetic containing the fine-particle zinc oxide powder of the present invention is arbitrary, and broadly includes powder-based, solubilized-based, emulsified-based, powder-dispersed-solubilized, powder-dispersed-emulsified, powder-dispersed oil-based, etc. You can take it.

The use is also optional, such as lotion, emulsion, cream,
It can be used in a wide range of cosmetics, including facial cosmetics such as cosmetic oils, and makeup cosmetics such as foundations, powders, lipsticks, blushers, and eye shadows.

[Effects of the Invention] The cosmetic containing fine-particle zinc oxide powder according to the present invention has a good transparency, so when applied to the skin, there is no whiteness, and it has an excellent ultraviolet ray prevention effect, and is gentle on the skin. It gives a crisp feeling on use and also has good dispersion stability in cosmetic bases. moreover,
Since it is a powder, there is no need to worry about skin irritation or allergies like with liquid UV absorbers.
It is a cosmetic with good safety.

[Example] Next, an example of manufacturing a particulate zinc oxide powder of the present invention and an example in which the particulate zinc oxide powder was blended into a cosmetic will be shown. The present invention is not limited thereby.

Production Example 1 A 0.1M aqueous sodium carbonate solution is added to a 1M aqueous zinc chloride solution at a weight ratio of 1:1. Addition rate is 25
The ratio was expressed as ml/min. After stirring for 30 minutes to obtain a white hydrosol, 0.15M sodium alkylbenzenesulfonate was added to make the sol lipophilic, and then 25 ml of xylene was added for flushing to obtain a white organosol. This material was dried under reduced pressure to remove xylene and the particle size was 70 to 100 Å.
1 g of fine particle zinc oxide powder was obtained. This fine-particle zinc oxide powder is lipophilic and suitable for blending into oil-based cosmetics.

Production Example 2 A hydrophilic fine-particle zinc oxide powder was obtained in the same manner as Production Example 1 except that the sodium alkylbenzenesulfonate in Production Example 1 was replaced with sodium lauryl sulfate. This product is suitable for blending into aqueous cosmetics.

Example 1 (Lotion) Glycerin 3.0% by weight Propylene glycol 2.0 Oleyl alcohol 0.1 POE(20) Sorbitan monolaurate
2.0 Ethanol 10.0 Flavor 0.1 Dye Appropriate amount Fine particle zinc oxide powder (obtained in Production Example 2)
Add 1.0% of water and dissolve (aqueous phase). (ethanol part). An ethanol portion was added to the aqueous phase for solubilization to obtain a lotion. The resulting lotion has a refreshing feel, does not leave any white spots when applied to the skin, has good transparency, has UV protection effects, and is also excellent in anti-inflammatory effects on the skin. was. Furthermore, since the particle size of the fine zinc oxide powder was small, the dispersibility was good even without adding a thickener or the like.

Example 2 (Sunscreen cream) Stearic acid 10.0% by weight Stearyl alcohol 4.0 Butyl stearate 6.0 Glyceryl monostearate (self-emulsifying type)
2.0 Flavor Appropriate amount Propylene glycol 10.0 Glycerin 3.0 Potassium hydroxide 0.4 Fine particle zinc oxide powder (obtained in Production Example 2)
4.0 Add the remainder of the water, dissolve and keep at 70℃ (aqueous phase). Dissolve and keep at 70℃ (oil phase). The oil phase was added to the water phase, emulsified, and cooled to obtain cream. The resulting cream had particularly excellent UV protection effects.

Example 3 (Sunscreen emulsion) Stearic acid 2.0% by weight Setanol 1.5 Vaseline 3.0 Liquid paraffin 8.0 POE(10) monooleate 2.0 Fragrance Appropriate amount Glycerin 2.0 Propylene glycol 5.0 Triethanolamine 1.0 (10) Fine particle zinc oxide powder (manufacturing example What you got in 2)
5.5 (11) Water Add the remaining part (11) and dissolve and keep at 70℃ (water phase). Dissolve and keep at 70℃ (oil phase). The oil phase was added to the water phase, emulsified, and cooled to obtain a milky lotion. The resulting emulsion had particularly excellent UV protection effects, and also had a refreshing feel upon use.

Example 4 (Foundation) Stearic acid 2.8% by weight Propylene glycol monostearate
2.8 Glyceryl monostearate (self-emulsifying type)
2.8 Liquid paraffin 24.6 Triethanolamine 1.4 Propylene glycol 15.0 Fine particle zinc oxide powder (obtained in Production Example 1)
6.0 Iron oxide red 1.5 Iron oxide yellow 2.5 Add an appropriate amount of fragrance, an appropriate amount of preservative, and the remainder of water to dissolve and keep at 70℃ (aqueous phase). Dissolve and disperse in this and keep at 70℃ (oil phase). The oil phase was added to the water phase, emulsified, and cooled to obtain a foundation.

Example 5 (white powder) Talc 10.2% by weight Titanium oxide 10 Fine particle zinc oxide powder (obtained in Production Example 1)
77.0 Iron oxide red yellow black 1.8 Iron oxide yellow 2.5 Flavor appropriate amount The above ingredients were mixed to obtain white powder. When applied to the skin, this product had good transparency, did not leave a white appearance, and had an excellent makeup-reducing effect. In addition, the UV protection effect was sufficient.

Claims (1)

[Claims] 1 Average particle size obtained by converting colloidal particles in a hydrosol of zinc sulfate or zinc chloride prepared in an aqueous solution into lipophilic form with an anionic surfactant, flushing with an organic solvent, and removing the organic solvent by drying. A cosmetic comprising fine particle zinc oxide powder with a particle size of more than 50 Å and less than 100 Å.