JPS5842167B2 - skin cosmetics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to skin cosmetics, particularly sunscreen cosmetics for protecting the skin from ultraviolet rays.

Conventionally, titanium oxide has been used in large quantities in cosmetics as a white pigment, and in sunscreen cosmetics, ultraviolet absorbers such as para-aminobenzoic acid derivatives and cinnamic acid derivatives (hereinafter simply referred to as ultraviolet absorbers) are also used in sunscreen cosmetics. ) is used in combination with

Among them, the maximum particle size is 0.1 μ or less and the average particle size is 30 to 40 m.
μ's ultrafine particle titanium oxide has a remarkable effect of blocking ultraviolet rays, and unlike conventional powder additives, there is no unnatural appearance when applied to the skin, making it an extremely useful sunscreen agent. This is as shown in Publication No.-42502.

However, these titanium oxides are hydrophilic and difficult to incorporate into oily bases, and have very strong surface activity, so they have the drawback of being subject to considerable prescription regulations.

In view of the above circumstances, as a result of intensive research, the present inventors have found that by subjecting titanium oxide to a special hydrophobic surface treatment, it will be possible to incorporate it into lipophilic bases, and the surface activity will also be suppressed. Furthermore, they discovered that if the above-mentioned hydrophobized titanium oxide, a specific amount of carboxyvinyl polymer, an amino acid with an isoelectric point of 6 or higher, and a polyoxyethylene polyoxypropylene block polymer type surfactant were blended, Uroko manufactures cosmetics that have anti-scald effect, are safe, have excellent water resistance, and have good stability despite being difficult to use due to low viscosity. They discovered this and completed the present invention.

That is, in the present invention, titanium oxide powder is mixed with titanium oxide powder in a proportion of 2 to 20% by weight based on the general formula R1C00R2 (in the formula R
1 represents a straight chain or side chain fatty acid residue having 11 to 23 carbon atoms, and R2 represents a straight chain or side chain higher alcohol residue having 12 to 24 carbon atoms.

) Hydrophobized titanium oxide obtained by adding it to a nonpolar solvent with a boiling point of 66 to 260°C and heating it together with one or more monoesters represented by The present invention provides a skin cosmetic composition characterized by blending a polyoxyethylene polyoxypropylene block polymer type surfactant, an amino acid having an isoelectric point of 6 or higher, and a polyoxyethylene polyoxypropylene block polymer type surfactant.

Various methods have been known for the hydrophobization treatment of pigments, but the above-mentioned hydrophobization treatment is a completely new method.

The titanium oxide pigment that can be used in the present invention is selected from rutile-type titanium oxide, anatase-type titanium oxide, non-grade titanium oxide, hydratable titanium oxide, titanium oxide modified with other metal oxides, etc. The shape and size of the particles are not particularly limited, but from the viewpoint of sun protection effect,
Ultrafine titanium dioxide having a maximum particle size of 0.1 μm or less and an average particle size of 30 to 40 mμ is preferable.

The monoester reaction treatment agents used in the present invention include:
The fatty acid side is lauric acid, myristic acid, palmitic acid,
Stearic acid, oleic acid, 2hexyldecanoic acid, 2-
hebutyl undecanoic acid, 2-octyl dodecanoic acid, 2-
It is a linear or side chain fatty acid having 12 to 24 carbon atoms such as decyltetradecanoic acid, and the higher alcohol side includes lauryl alcohol, myristyl alcohol, stearyl alcohol, oleyl alcohol, 2-hexyldecanol, 2- 1 carbon number such as hebutylundecanol, 2-octyldodecanol, 2-decyltetradecanol, etc.
These are monoester compounds based on linear or side chain higher alcohols having 2 to 24 atoms.

Specifically, lauryl laurate, lauryl myristate, lauryl palmitate, lauryl stearate, lauryl oleate, lauryl-2-hexyldecanoate, lauryl-2-hebutylundecanoate, lauryl-2-octyldodecane. ate, lauryl-2-decyltetradecanoate, myriseteel myristate, myriseteel palmitate, myriseteel stearate, myriseteel oleate, myriseteel-2-hexyldecanoate, myriseteel-2-hebutylundecanoate ate, myritel-2-octyldodecanoate, myritel-2-decyltetradecanoate, palmityl palmitate, palmityl stearate, palmityl oleate, palmityl-2-hexyldecanoate, palmityl-2-heptylundecanoate ate, palmity-2-octyldodecanoate, palmity-2-decyltetradecanoate, stearyl stearate, stearyl oleate, stearyl-2-
Hexyldecanoate, stearyl-2-heptyl undecanoate, stearyl-2-octyldodecanoate, stearyl-2-decyltetradecanoate, oleyl oleate, oleyl-2hexyldecanoate, oleyl-2- Hebutyl undecanoate, oleyl-2-octyldodecanoate, oleyl-2-decyltetradecanoate, 2-hexyldecyl-2L hexyldecanoate, 2-hexyldecyl-2'-hebutyl undecanoate, 2-hexyldecyl-2-octyldodecanoate, 2-hexyldecyl-7-decyltetradecanoate, 2-hebutylundecyl-2'-hebutylundecanoate, 2-hebutylundecyl-
2'-octyldodecanoate, 2-hebutylundecyl-2-decyltetradecanoate, 2-octyldobutyl-2-octyldodecanoate, 2-octyldobutyl-2-butyltetradecanoate, Examples include 2-decyltetrazosyl-2'-decyltetradecanoate.

Among the above-mentioned monoester-based reaction treatment agents, linear-side chain type or side chain-side chain type monoester compounds that are liquid at room temperature are preferred because they facilitate uniformity of the reaction system.

Further, saturated monoester compounds are more preferable than unsaturated monoester compounds because they are less likely to cause side reactions or decomposition reactions.

Specifically, the nonpolar reaction solvent used in the present invention is a synthetic saturated side chain hydrocarbon (manufactured by Etsuo Standard Oil Co., Ltd., trade name Isopar C, D, E.

G, H, L, M, etc.), saturated linear hydrocarbons (hexane, octane, decane, dodecane, etc.), and aromatic hydrocarbons (benzene, toluene, xylene, etc.).

Among the above nonpolar reaction solvents, synthetic saturated side chain hydrocarbon solvents are preferred in order to obtain a white, odorless, hydrophobized titanium dioxide pigment.

In the case of aromatic hydrocarbon solvents, the pigment may yellow and deteriorate depending on the reaction temperature and reaction time.

The hydrophobic surface-treated titanium oxide used in the present invention can be easily added to lipophilic bases, which was difficult to add to untreated titanium oxides, and because the untreated titanium oxide has high surface activity. Carboxyvinyl polymer, which was difficult to add (
It can also be blended into an emulsifying system containing a polymer having a reactive group such as Carbopol (trade name: Carbopol B, F, manufactured by Gutdrich Chemical Co., Ltd.).

Furthermore, in the present invention, a carboxyvinyl polymer neutralized with an amino acid having an isoelectric point of 6 or more and a polyoxyethylene-polyoxypropylene block polymer type surfactant are used as a cosmetic containing the hydrophobized titanium dioxide. By selecting the emulsified cosmetics to contain, the surfactant component can be reduced by 115 to 1/10 compared to conventional emulsified products.
Since it is possible to adjust the paternal pH to the acidic side close to the skin pH, it is possible to obtain cosmetics with extremely high skin safety.

The amount of carboxyvinyl polymer used at this time is preferably 0.03 to 0.1 weight φ based on the cosmetic.

Amino acids with an isoelectric point of 6 or higher include L-arginine, L-arginine,
-IJ dine, L-histidine, β-alanine, etc. are used, but basic amino acids are particularly preferred.

The blending amount of these amino acids is appropriately selected so that the pH of the cosmetic is set within a preferable range.

In addition, since the carboxyvinyl polymer is not sufficiently neutralized with an amino acid having an isoelectric point of less than 6, the viscosity of the system hardly increases, and therefore a cosmetic with good stability cannot be obtained.

The polyoxyethylene-polyoxypropylene block polymer type surfactant is preferably one represented by the following general formula, and the blending amount is 0.05 to 1.0% by weight, preferably 0.1 to 0.0% by weight. This is Section 5.

H3 )-IO(CI(2CT(20)n(a(2CI(0
)rn(C)(2C)(20)n'H This type of surfactant is commercially available from Mudenka Kogyo ■ under the name Pluronic.
0 to 2,000 and the content of ethylene oxide is 20 to 60 φ, particularly highly stable cosmetics can be obtained.

In addition, cosmetics containing hydrophobic titanium oxide, carboxyvinyl polymer, basic amino acid, and polyoxyethylene polyoxypropylene block polymer type surfactant contain triglyceride, which is liquid at room temperature. It was confirmed that when the content is 5 to 15%, the stability against separation is particularly high.

Next, the effects of the present invention will be described using sunscreen cosmetics as an example.

In general, sunscreen cosmetics are required to: 1) Must have a sunscreen effect.

2) Highly safe for the skin.

3) Good water resistance.

4) Good usability.

5) It should be stable with little deterioration over time.

However, in conventional sunscreen cosmetics,
There was no product that satisfactorily met all of these conditions.

In other words, in an attempt to increase the sunscreen effect, increasing the amount of conventional powder such as titanium oxide often impairs the feeling of use, and adding an unnecessarily large amount of ultraviolet absorbers also impairs skin safety. .

In the present invention, by using ultrafine titanium dioxide particles that have a high ultraviolet blocking effect, the sunscreen effect can be enhanced without impairing skin safety and usability.

Figure 1 shows the sunscreen effect of various titanium oxide powders, and shows the sunscreen effects of titanium oxide powders in liquid paraffin.
This is the result of measuring the ultraviolet absorption rate using a Hitachi Model 624 digital spectrophotometer after dispersing the sample into a quartz cell with a thickness of 10 mm.

Compared to titanium oxide (anatase) (average particle size: 0.1μ) and titanium oxide (rutile) (average particle size: 0.1μ), ultrafine particle titanium oxide has a higher ultraviolet absorption rate, and even with hydrophobic surface treatment. The effect does not decrease, but rather tends to increase.

Skin safety is particularly important because sunscreen cosmetics are used under harsh conditions for the skin, such as under sunlight exposure, but conventional products contain a large amount of UV absorbers, In addition, in the case of emulsion systems that are easy to use, it is necessary to increase the amount of surfactant used, and the pH of the system is often high, so there are many problems in terms of skin safety. It was something.

In this regard, according to the present invention, a polymer emulsifier with high skin safety, which is a carboxyvinyl polymer neutralized with basic amino acids and a block polymer of polyoxyethylene-polyoxypropylene, is used, and the amount used is lower than that of conventional emulsifiers. A small amount of 115 to 10 l/10 of the product is sufficient, and
Because the pH of the system can be adjusted to the acidic side close to the pH of the skin, it is an extremely safe base. By adding hydrophobically treated powder, a sunscreen cosmetic with excellent safety can be obtained.

Water resistance is a necessary condition for sunscreen cosmetics to prevent run-off due to sweating or bathing, but conventional products often have poor water resistance due to the high content of surfactants. However, there is a contradiction in that if an attempt is made to improve water resistance by creating an oily product or a water-in-oil type emulsion product, the usability deteriorates.

In this regard, although the sunscreen cosmetic according to the present invention is a water-in-oil type emulsion product, it uses the above-mentioned hydrophobic powder, and the amount of surfactant in the system is small, and carboxyvinyl The polymer has film properties, making it an extremely water resistant product.

Regarding usability, since sunscreen cosmetics are often used in the summer, something light is desired, but conventional products are designed to have good water resistance and stability over time. Many of these products are oily or creamy, and they have the disadvantage of being sticky and unpleasant to use.

In this regard, the sunscreen cosmetic according to the present invention is a water-in-oil type emulsion with a very low viscosity, so it has a very light feel on use, and the emulsion system contains a large number of emulsified particles. After being applied to the skin, the product has a unique feeling of use that is not found in conventional products.

All products are required to be stable products that do not deteriorate over time, but emulsified products are inherently unstable, and it is a difficult technology to keep low-viscosity emulsions stable for long periods of time. .

The inventors also needed to further consider this point.

In other words, one way to improve the stability over time in an emulsion system in which polymers are added is to increase the amount of polymer added to increase the viscosity of the external phase. An increase in the amount of polymer causes a drawback in that after application to the skin, the film becomes more filmy, causing "kinking" (a phenomenon in which it peels off into pieces).

The present inventors have found that in carboxyvinyl polymer systems, this addition limit needs to be less than 0, t%.

In addition, this carboxyvinyl polymer o is the most effective additive to satisfy the stability over time as a product in an emulsion system with 1% or less of basic amino acid neutralization.
They discovered that a polyoxyethylene-polyoxypropylene block polymer type surfactant was the most suitable, and were able to obtain a cosmetic with excellent usability and stability.

If this system has a viscosity of 300 cps or more, it will be stable enough to withstand shelf life in delirium, which is not the case with conventional emulsified products, as the emulsified particles of this system are large, ranging from 1 to 20 microns. It is a feature.

Next, the present invention will be explained in more detail using reference examples and examples.

Reference Example 1 Hydrophobization treatment of titanium oxide powder 100 g of anatase-type ultrafine particle titanium dioxide with an average particle size of 0.03 μm was added to a reactor equipped with a water collection tube, and a nonpolar reaction solvent and a saturated linear hydrocarbon n-decane were added. 400 g and 6.6 g of reaction treatment agent 2-octyldodecyl-2'-hebutyl undecanoate (molecular weight 564) were added at room temperature.
Stir and mix for 0 minutes and add 150% dry purified high purity nitrogen gas.
5°C while introducing rrLl/min amount into the reactor.
/min to reach an internal temperature of 172°C, the reaction solvent n-decane begins to reflux.

Since n-decane azeotropes with water adhering to titanium dioxide, the reaction is carried out for 5 hours while removing this from the reaction system.

The amount of water removed at this time was 1.2 g.

After the reaction is completed, the reaction solvent and excess unreacted treatment agent are removed from the furnace.

Thereafter, 400 g of hexane was added, stirred at room temperature, and then centrifuged to completely remove physically adsorbed or attached reaction solvent or unreacted treatment agent.

Thereafter, the mixture is dried at 50 to 60° C. and about 60° C. and pulverized to obtain a white, odorless, hydrophobized ultrafine titanium dioxide pigment product.

The above-mentioned reaction-treated titanium dioxide pigment does not disperse in water at all, but floats on the water surface, and is well dispersed in organic solvents such as n-hexane, benzene, chloroform, ethyl acetate, and ethanol. In a two-phase dispersion medium such as paraffin, it was always selectively dispersed in the water-based phase, and over time it all aggregated at the interface and did not migrate to the aqueous phase.

Furthermore, even after washing 1 g of the reaction-treated titanium dioxide pigment in 70 ml of benzene under reflux for 1 hour, its hydrophobicity was not lost and its properties were completely unchanged from those immediately after the reaction.

In addition, the control untreated titanium dioxide pigment was always selectively dispersed in the water phase in a water-organic solvent two-phase dispersion medium, and did not migrate to the organic solvent phase at all, exhibiting the opposite behavior to the reaction-treated titanium dioxide pigment. present.

Reference Example 2 Hydrophobizing Treatment of Titanium Oxide Powder In Reference Example 1, octyldodecyl myristate was used instead of 2-octyldodecyl-2-hebutylundecanoate.

The obtained hydrophobized titanium oxide exhibited the same behavior as in Reference Example 1.

Reference Example 3 Hydrophobizing Treatment of Titanium Oxide Powder In Reference Example 1, 2-decyltetradecyl-2-decyltetradecanoate was used instead of 2-octyldodecyl-2'-heptylundecanoate.

The obtained hydrophobized titanium oxide exhibited the same behavior as in Reference Example 1.

Reference Example 4 Hydrophobizing treatment of titanium oxide powder In Reference Example 1, 2-hebutylundecyl-2 was used instead of 2-octyldodecyl-2-hebutylundecanoate.
- Hebutyl undecanoate was used.

The obtained hydrophobized titanium oxide exhibited the same behavior as in Reference Example 1.

Example 1 (Formulation) ■ Ultrafine particle titanium dioxide obtained in Reference Example 1 2.0 φ ■ Olive oil 15.0 ■ Polyoxyethylene polyoxypropylene block polymer (Pluronic L-62) 0.5 ■ Carboxyvinyl polymer ( Carbopol 94L) 0.05■ L-Arginine 0.05■ Ethanol (
95 rice cake) 5.0 ■ EDTA-3N a O, 01 ■
Ion exchange water 75.59■ 2-ethylhexyl-P-dimethylaminobenzoate 2.0 [Phase] Preservative 0.10 Fragrance
0.1 (Production method) Add ■■ to a heated solution of ■■■, and after uniformly dispersing, add 0 and use this as an oil phase.

■■■■ Add ■ to the uniformly heated and dissolved [Yes],
This is called the aqueous phase.

The oil phase is added to the water phase, stirred and emulsified, then homogenized and cooled to room temperature.

The resulting product had a viscosity of 710 cps and a pH of 6.5.

(Usability and stability test) In the formulation of Example 1, the amount of carboxyvinyl polymer <Carbopol 941 (B, F, USA, manufactured by Gutdrich Chemical Company)> was varied to test usability and stability. investigated.

Usability was determined by a panel of 10 people who applied the sample to the face and then judged the fit of the kinks 7 when applying the foundation.Stability was determined by testing each sample at 50℃, 37℃, room temperature and Judgment was made from the state of separation of the emulsion after it was left at 0°C for about one month.

The results are shown in Table 1.

Table 1 Carbopol 941 (%) Usability Stability 0
0 × 0.02 0 △ 0.03 0 0 0.05 0 0 0.10 △ 0 0.20 X ○ 0630 X ○ In addition, when untreated titanium oxide is used instead of hydrophobic titanium oxide, The emulsification was destroyed by aggregation, and the emulsion quickly separated.

* Judgment Criteria Usability Stability ○: Good "Wrinkle 9" ○: No abnormality under each condition
None △: Somewhat skewed △: One or more of the conditions occur
Separated ×: “Cruvel 7 occurs” ×: Separated under each condition Next, in the formulation of Example 1, L-arginine (isoelectric point 10.
76) was replaced with another amino acid and its stability was observed.

The results are shown in Table 4, and it can be seen that when an amino acid with an isoelectric point of less than 6 is used, a cosmetic with good stability cannot be obtained.

Table 4 Amino acid (isoelectric point) stability Viscosity pHL-lysine (9,74) 0 680 cps 6. OB-
Alanine (6,00) 0 310cps 4.
6 Glycine (5,97) △ 80cps
4.2 Glutamic acid (3,22) x 40
cps 3.5 no additives x 40cps 3.
7 * Stability test methods and criteria are the same as Table 1.

Mucus cold is a value measured using a Brookfield viscometer (30°C).

(Water resistance test) A certain amount of ultraviolet absorber (2-ethylhexy I-ray P-dimethylaminobenzoate, 2
weight φ) and apply these uniformly to the skin.

The amount of ultraviolet absorber extracted by ethanol (99%) from a certain area of the coated area was compared before and after washing the coated area with water to determine the residual rate of the ultraviolet absorber.

The results are shown in Figure 2. The samples were (N ethanol 50% aqueous solution, [F]) stearic acid-triethanolamine soap emulsified cream with an oil content of 20%, (C) nonionic surfactant emulsified cream with an oil content of about 30%, (c) olive oil 3
0% liquid paraffin and 70% liquid paraffin, (2) the cosmetic composition of Example 1.

From FIG. 2, it can be seen that the cosmetic of Example 1 has a higher residual rate of ultraviolet absorber than other cosmetics, that is, it has good water resistance.

Next, Table 2 shows the results of comparing the separation stability after 1 month in the formulation of Example 1 by changing the type of nonionic surfactant.

In the table, product viscosity change is measured using a Brookfield viscometer (30°
C), and the stability evaluation criteria are: ○: No separation observed, △: Very slight separation observed, ×
: By separation.

*The polyoxyethylene polyoxypropylene block polymers shown in Table 3 were used.

Example 2 Sunscreen cosmetic (emulsion) (Formulation) ■ Ultrafine particle titanium dioxide obtained in Reference Example 1 ■ Olive oil ■ Squalane ■ Polyoxyethylene polyoxypropylene block polymer (Pluronic L-64) ■ Carboxyvinyl polymer (Carbopol 941) ■ L-arginine ■ Ethanol (95%) ■ Propylene glycol ■ EDTA-3Na [Phase] Ion-exchanged water 02-ethylhexyl-P-dimethylaminobenzoate @ preservative 0 fragrance 1. 0 ■ 15.0 5.0 0.3 0.06 0.06 0 5.0 0.01 67.37 (Production method) Same as Example 1, viscosity 700 cps, pH 6.5
I obtained a sunscreen cosmetic (emulsion).

Example 5 ■Purified water 71.89φ ■Polyethylene glycol 7.0■ Carboxyvinyl polymer (Carbopol 941) 0.05■ Polyoxyethylene polyoxypropylene block polymer (Pluronic L=64) 0.5■ L-arginine 0.05■ Ethanol
5.0 ■ EDTA-3N a
O, 01 ■ 2-Ethylhexyl-P-dimethylaminobenzoate 2.5 ■ Squalane 12.0 [Phase] Hydrophobic titanium oxide obtained in Reference Example 2 1.0 0 Preservative Appropriate amount @ Fragrance Appropriate amount ■ Add (1), (2), (2), (2), and (2), stir and dissolve uniformly, and use this as the aqueous phase.

■、■、■、0. [Phase] is added to the heated and dissolved [Phase], and this is used as an oil phase.

After heating the aqueous phase, the oil phase is added, emulsified by stirring, homogenized, and cooled to room temperature.

The resulting product has a viscosity of 700 cps and a pH of 6.5.
Met.

[Brief explanation of the drawing]

Figure 1 is a graph showing the UV absorption effect of various titanium oxide powders, and Figure 2 is a graph showing the UV absorber residual rate after various samples containing UV absorbers were applied to the skin and washed with water.
The length of the arrow in FIG. 2 indicates the width of the variation in the survival rate.

Claims (1)

[Scope of Claims] 1 Titanium oxide powder is prepared using a compound having the general formula R1C00R2 (wherein R1 represents a linear or side chain fatty acid residue having 11 to 23 carbon atoms) with a weight ratio of 2 to 20 to titanium oxide. The expression R2 represents a linear or side chain higher alcohol residue having 12 to 24 carbon atoms. Hydrophobized titanium oxide obtained by heating in addition to the above, a carboxyvinyl polymer of 0.03 to 0.1 weight strength, an amino acid with an isoelectric point of 6 or more, and a polyoxyethylene polyoxypropylene block polymer type interface. A skin cosmetic comprising an active agent. 2. The skin cosmetic according to claim 1, wherein the titanium oxide is ultrafine particle titanium oxide with a maximum particle size of 0.1 μm or less and an average particle size of 30 to 40 mμ. 3. The skin cosmetic according to any one of claims 1 to 2, wherein the amino acid is L-arginine. 4. The skin cosmetic according to any one of claims 1 to 2, wherein the amino acid is L-lysine. 5 Claim 1 in which the amino acid is β-alanine
The skin cosmetic according to any one of Items 1 to 2. 6 The amount of polyoxyethylene polyoxypropylene block polymer type surfactant added to the cosmetic is 0.
The skin cosmetic according to any one of claims 1 to 5, which has a weight ratio of 1 to 0.5. 7. The skin cosmetic according to any one of claims 1 to 6, wherein the skin cosmetic has a viscosity change of 300 to 2000 cps.