JP7828632B2 - Oil-in-water emulsion sunscreen cosmetic - Google Patents

Description

This invention relates to an oil-in-water emulsion sunscreen cosmetic that is non-sticky due to UV absorbers, has a smooth application, and exhibits good stability over time.

Sunburn caused by ultraviolet (UV) radiation leads to skin browning, loss of skin elasticity, and wrinkle formation. Therefore, cosmetics containing UV absorbers are used to prevent these problems. UV radiation reaching the Earth's surface alters collagen and elastin fibers in the dermis, causing photoaging and accelerating skin aging. It also causes sunburn, resulting in redness. Therefore, protecting the skin from UV radiation is one of the important functions of cosmetics.

Sunscreen cosmetics are used to protect the skin from the harmful effects of ultraviolet (UV) rays. Emulsified cosmetics are classified into water-in-oil and oil-in-water types. Water-in-oil types offer excellent water resistance but can result in an undesirable sticky feeling, while oil-in-water types are less likely to cause such an undesirable feeling but offer less UV protection compared to water-in-oil types.

In oil-in-water emulsion sunscreen cosmetics, one way to achieve high UV protection is to include a large amount of UV absorbers. However, including a large amount of UV absorbers results in a sticky texture and poor stability over time. Furthermore, increasing the amount of surfactants to improve stability leads to even stickier texture and poor spreadability. There has been a need for an oil-in-water emulsion sunscreen cosmetic that solves these problems, achieving both high UV protection and a non-sticky, easily spreadable texture.

Prior art concerning oil-in-water emulsion sunscreen cosmetics includes a technology (Patent Document 1) that combines a sulfonic acid group-containing water-soluble UV absorber, bis-ethyloxyphenol methoxyphenyl triazine, diethylamino hydroxybenzoyl hexyl benzoate, and ethylhexyl triazone with a polar oil, a higher alcohol, and a nonionic surfactant to obtain an oil-in-water emulsion sunscreen cosmetic that is non-greasy and has a refreshing feel; and a technology (Patent Document 2) that combines a salicylic acid-based liquid UV absorber, alkyl silicone wax, and low-viscosity silicone oil to obtain an oil-in-water emulsion sunscreen cosmetic that has high UV protection while being non-greasy and having excellent long-term stability. However, while these technologies have good long-term stability and non-greasy properties, they have not yet achieved a smooth, spreadable feel.

Japanese Patent Publication No. 2018-145117 Japanese Patent Publication No. 2020-111542

The objective of this invention is to provide an oil-in-water emulsion sunscreen cosmetic that is non-sticky due to UV absorbers, has a smooth application, and exhibits good stability over time.

That is, the present invention comprises the following components (A) to (E),
(A) 0.5 to 2.0% by weight of sucrose stearate (B) 0.05 to 1.0% by weight of sodium stearoyl methyl taurate
(C) 1.0 to 5.0% by weight of one or more higher alcohols selected from cetyl alcohol, stearyl alcohol, and behenyl alcohol (D) 1.5 to 5.0% by weight of polyglyceryl-10 diisostearate
The present invention also provides (E) an oil-in-water emulsion sunscreen cosmetic containing 3.0 to 18.0% by weight of an ultraviolet absorber.

Furthermore, the present invention provides an oil-in-water emulsion sunscreen cosmetic characterized by the HLB value of sucrose stearate (component A) being 3 to 7.

Furthermore, the present invention provides an oil-in-water emulsion sunscreen cosmetic characterized in that 50% by weight or more of the higher alcohols in component (C) are behenyl alcohol.

This invention provides an oil-in-water emulsion sunscreen cosmetic that is non-sticky due to UV absorbers, has a smooth application, and exhibits good stability over time.

The sucrose stearate content of component (A) is preferably 0.5 to 2.0% by weight, and more preferably 0.7 to 1.5% by weight, relative to the oil-in-water emulsion sunscreen cosmetic. If the content is less than 0.5% by weight, the stability over time may be poor. On the other hand, if it exceeds 2.0% by weight, the spreadability may be poor.

The HLB value of sucrose stearate in component (A) is not particularly limited, but 3 to 7 is more preferable from the viewpoint of long-term stability, non-stickiness, and spreadability. Furthermore, this invention may contain one or more types of sucrose stearate with different HLB values. The HLB values of sucrose stearate in this invention are based on the values listed in the catalog (Surfhope SE COSME, May 2001 (Mitsubishi Chemical Foods)). When two or more types of sucrose stearate are included, the HLB value can be calculated assuming additivity.

Specific examples of sucrose stearate, component (A), include, but are not limited to, Surfhope SE COSME C-1800, Surfhope SE COSME C-1801, Surfhope SE COSME C-1802, Surfhope SE COSME C-1803, Surfhope SE COSME C-1805, Surfhope SE COSME C-1807, Surfhope SE COSME C-1809, Surfhope SE COSME C-1811, Surfhope SE COSME C-1815, and Surfhope SE COSME C-1816 (all manufactured by Mitsubishi Chemical Foods Co., Ltd.).

The content of sodium stearoyl methyl taurate in component (B) is preferably 0.05 to 1.0% by weight, and more preferably 0.2 to 0.7% by weight, relative to the oil-in-water emulsion sunscreen cosmetic. If it is less than 0.05% by weight, the stability over time may be poor. On the other hand, if it exceeds 1.0% by weight, a sticky feeling may result.

The content of one or more higher alcohols selected from cetyl alcohol, stearyl alcohol, and behenyl alcohol in component (C) is preferably 1.0 to 5.0% by weight, and more preferably 2.0 to 4.0% by weight, relative to the oil-in-water emulsion sunscreen cosmetic. If the content is less than 1.0% by weight, the stability over time may be poor. On the other hand, if it exceeds 5.0% by weight, the stability over time may be poor, or the spreadability may be reduced.

Furthermore, from the perspective of good spreadability, it is more preferable that 50% or more by weight of the higher alcohols in component (C) be behenyl alcohol.

The content of polyglyceryl-10 diisostearate in component (D) is preferably 1.5 to 5.0% by weight, and more preferably 2.5 to 4.0% by weight, relative to the oil-in-water emulsion sunscreen cosmetic. If the content is less than 1.5% by weight, the stability over time may be poor. On the other hand, if it exceeds 5.0% by weight, the spreadability may be poor.

The content of the UV absorber in component (E) is preferably 3.0 to 18.0% by weight, and more preferably 3.0 to 15.0% by weight, relative to the oil-in-water emulsion sunscreen cosmetic. If the content is less than 3.0% by weight, the stickiness caused by the UV absorber, which is a problem of this invention, will not occur, but sufficient UV protection may not be obtained. On the other hand, if it exceeds 18.0% by weight, a sticky feeling may result.

For component (E), UV absorbers commonly used in cosmetics can be used. Examples include, but are not limited to, ethylhexyl methoxycinnamate, octocrylene, dimethicone diethyl benzalmalonate, polysilicone-15, t-butyl methoxydibenzoylmethane, ethylhexyl triazone, diethylamino hydroxybenzoyl hexyl benzoate, bis-ethylhexyloxyphenol methoxyphenyl triazine, oxybenzone-3, methylene bisbenzotriazolyl tetramethylbutylphenol, phenylbenzimidazole sulfonic acid, homosalate, ethylhexyl salicylate, and dimethyl PABA ethylhexyl. Furthermore, one or more of these can be used as needed.

The oil-in-water emulsion sunscreen cosmetic composition of the present invention may contain various components, such as anionic surfactants, cationic surfactants, nonionic surfactants, oils, preservatives, humectants, thickeners, colorants, metal ion chelating agents, antioxidants, cosmetic ingredients, fragrances, cooling agents, pH adjusters, etc., as appropriate, within limits that do not impair the effects of the invention, depending on the intended use.

The dosage form of the oil-in-water emulsion sunscreen cosmetic of the present invention is not particularly limited, but examples include lotions and creams.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples. All content in the examples is expressed in weight percent.

Oil-in-water emulsion sunscreen cosmetics having the compositions listed in Tables 1 to 10 below were prepared. For the evaluation of "stability over time," the products were stored in a constant temperature bath at 40°C for 6 months, and then observed visually and the emulsion particles using an optical microscope (Olympus BX53) were examined and evaluated according to the following criteria. In addition, a panel of 15 experts evaluated the "non-stickiness" and "spreadability" of each cosmetic when applied.
(Preparation method)
1. Heat Part A to 70°C and mix until uniform.
2. Heat part B to 70°C, mix it uniformly, then mix part A and part B together and cool to 35°C.
(Evaluation method)
The following criteria were used to define "stability over time."
◎: There is no significant change in appearance, and there is no change in the emulsion particles.
○: There is no significant change in appearance, but the emulsion particles have become larger.
×: Oil separation is observed, and changes in appearance are seen.
Regarding "non-stickiness," a panel of experts evaluated it and presented the following criteria.
◎: More than 13 people rated it as "not sticky."
○: 10 to 12 people rated it as "not sticky."
△: 6 to 9 people rated it as "not sticky."
×: Fewer than 5 people rated it as "not sticky."
The "ease of expansion" was evaluated by a panel of experts and presented according to the following criteria.
◎: More than 13 people rated it as having "good growth potential."
○: 10 to 12 people rated it as having "good growth."
△: 6 to 9 people rated it as having "good growth."
×: Fewer than 5 people rated it as having "good spreadability".

Examples 1 to 39, Comparative Examples 1 to 20: Oil-in-water sunscreen cream
*1: MT-100Z (manufactured by Teika Co., Ltd.)
*2: Elefac I-205 (manufactured by Nikko Chemicals Co., Ltd.)
*3: Nomucoat TAB (manufactured by Nisshin Oillio Co., Ltd.)
*4: KF-56A (manufactured by Shin-Etsu Chemical Co., Ltd.)
*5: Surfhope SE COSME C-1805 (manufactured by Mitsubishi Chemical Foods Co., Ltd.)
*6: Behenyl alcohol (manufactured by Higher Alcohol Industry Co., Ltd.)
*7: Echogum T (manufactured by CP Kelco U.S.)
*8: 1,3-Butylene glycol (manufactured by Daicel Chemical Industries, Ltd.)
*9: Mekkins-M (manufactured by Ueno Pharmaceutical Co., Ltd.)
*10: NIKKOL SMT (manufactured by Nikko Chemicals Co., Ltd.)
*11: NIKKOL Decaglyn 2-ISV (manufactured by Nikko Chemicals Co., Ltd.)

Table 1 shows that when the amounts of sucrose stearate shown in Examples 1-4 are included, the resulting cosmetic product exhibits excellent long-term stability, is non-sticky, and has a smooth, easily spreadable texture. On the other hand, Comparative Example 1, which contained less sucrose stearate than the specified amount, showed poor long-term stability, while Comparative Example 2, which contained more sucrose stearate than the specified amount, resulted in a poorly spreadable texture.

*12: Surfhope SE COSME C-1801 (manufactured by Mitsubishi Chemical Foods Co., Ltd.)
*13: Surfhope SE COSME C-1816 (manufactured by Mitsubishi Chemical Foods Co., Ltd.)

As shown in Table 2, the results indicate that even when sucrose stearate with different HLB values is included, as in Examples 5-15, the resulting cosmetic product exhibits excellent long-term stability, is non-sticky, and has a smooth, easily spreadable texture. Furthermore, it was found that when the HLB value of sucrose stearate is set to 3-7, the cosmetic product exhibits even greater long-term stability, non-stickiness, and smoothness.

*14: Surfhope SE COSME C-1205 (manufactured by Mitsubishi Chemical Foods Co., Ltd.)
*15: NIKKOL Decaglyn 5-SV (manufactured by Nikko Chemicals Co., Ltd.)
*16: GLUCATE SS EMULSIFIER (manufactured by Lubrizol)
*17: NIKKOL Decaglyn 5-HS (manufactured by Nikko Chemicals Co., Ltd.)
*18: NIKKOL MGS-AV (manufactured by Nikko Chemicals Co., Ltd.)
*19: NIKKOL SS-10V (manufactured by Nikko Chemicals Co., Ltd.)
*20: NIKKOL Hexaglyn 1-SV (manufactured by Nikko Chemicals Co., Ltd.)

We investigated the inclusion of other types of surfactants instead of sucrose stearate. The results are shown in Table 3. As shown in Comparative Example 3, the inclusion of sucrose laurate resulted in poor stability over time; as shown in Comparative Example 4, the inclusion of polyglyceryl-10 pentastearate resulted in poor spreadability; as shown in Comparative Example 5, the inclusion of methyl glucose sesquistearate resulted in poor stability over time and a sticky feel; as shown in Comparative Example 6, the inclusion of polyglyceryl-10 pentahydroxystearate resulted in a sticky feel; as shown in Comparative Example 7, the inclusion of glyceryl stearate resulted in poor stability over time; as shown in Comparative Example 8, the inclusion of sorbitan stearate resulted in poor stability over time and poor spreadability; and as shown in Comparative Example 9, the inclusion of polyglyceryl-6 stearate resulted in a sticky feel and poor spreadability.

The results in Table 4 show that when the amounts of sodium stearoyl methyl taurate shown in Examples 16-19 are included, the resulting cosmetic has excellent long-term stability, is non-sticky, and has a smooth, easily spreadable feel. On the other hand, Comparative Example 10, which contained less sodium stearoyl methyl taurate than the specified amount, exhibited poor long-term stability, while Comparative Example 11, which contained more sodium stearoyl methyl taurate than the specified amount, resulted in a sticky feel.

*21: Sodium stearoyl lactate (manufactured by Nikko Chemicals Co., Ltd.)
*22: Amisoft HS-11P (manufactured by Ajinomoto Co., Inc.)

We investigated the use of other types of surfactants instead of sodium stearoyl methyl taurate. The results are shown in Table 5. As shown in Comparative Example 12, the inclusion of sodium stearoyl lactinate resulted in poor spreadability, while as shown in Comparative Example 13, the inclusion of sodium stearoyl glutamate resulted in a sticky texture.

Table 6 shows that when the amount of behenyl alcohol, a higher alcohol, is included in the amounts shown in Examples 20-23, the resulting cosmetic composition exhibits excellent stability over time, is non-sticky, and has a smooth, easily spreadable texture. On the other hand, in Comparative Example 14, where the behenyl alcohol content was less than the specified amount, the stability over time deteriorated. In Comparative Example 15, where the behenyl alcohol content exceeded the specified amount, both stability over time deteriorated and the spreadability was poor.

*23: Stearyl alcohol NX (manufactured by Higher Alcohol Industry Co., Ltd.)
*24: Cetyl alcohol NX (manufactured by Higher Alcohol Industry Co., Ltd.)

As shown in Table 7, it was found that including stearyl alcohol as the higher alcohol, as in Example 24, results in a cosmetic product with excellent stability over time, no stickiness, and a smooth application. It was also found that including cetyl alcohol as the higher alcohol, as in Example 25, results in a cosmetic product with excellent stability over time, no stickiness, and a smooth application. Furthermore, when a portion of the stearyl alcohol was replaced with behenyl alcohol, as in Examples 26-28, it was found that the spreadability was further improved when behenyl alcohol accounted for 50% or more by weight of the higher alcohols. Furthermore, when a portion of the cetyl alcohol was replaced with behenyl alcohol, as in Examples 29-31, it was found that the spreadability was further improved when behenyl alcohol accounted for 50% or more by weight of the higher alcohols.

The results in Table 8 show that when polyglyceryl-10 diisostearate is included in the amounts shown in Examples 32 to 35, the cosmetic product exhibits excellent long-term stability, is non-sticky, and has a smooth, easy-to-spread texture. On the other hand, in Comparative Example 16, where the amount of polyglyceryl-10 diisostearate was less than the predetermined amount, the long-term stability deteriorated, and in Comparative Example 17, where the amount of polyglyceryl-10 diisostearate exceeded the predetermined amount, the spreadability deteriorated.

*25: NIKKOL Decaglyn 1-IS (manufactured by Nikko Chemicals Co., Ltd.)
*26: NIKKOL Decaglyn 2-SV (manufactured by Nikko Chemicals Co., Ltd.)

We investigated the inclusion of other types of surfactants instead of polyglyceryl-10 diisostearate. The results are shown in Table 9. As shown in Comparative Example 18, the inclusion of polyglyceryl-10 isostearate resulted in poor stability over time, and as shown in Comparative Example 19, the inclusion of polyglyceryl-10 distearate also resulted in poor stability over time.

The results in Table 10 show that when the amount of ethylhexyl methoxycinnamate, an ultraviolet absorber, is included as shown in Examples 36 to 39, the resulting cosmetic has excellent stability over time, is non-sticky, and has a smooth texture. On the other hand, in Comparative Example 20, where the amount of ethylhexyl methoxycinnamate, an ultraviolet absorber, exceeded the predetermined amount, the cosmetic had a sticky texture.

The following are examples of oil-in-water emulsion sunscreen cosmetics that are non-sticky due to UV absorbers, have a smooth application, and exhibit good stability over time. In all cases, satisfactory results were obtained in the same evaluations as described above.

Example 40 Oil-in-water type daytime moisturizing cream (ingredient name) Weight (%)
(Part A)
(1) Silicone-coated titanium oxide 3.0
(2) Zinc oxide 2.0
(3) Octocrylene*27 8.0
(4) Bis-ethylhexyloxyphenol methoxyphenyl triazine *28
1.5
(5) t-butyl methoxydibenzoylmethane*29 1.0
(6) Alkyl benzoate (C12-15) 7.0
(7) Diphenylsiloxyphenyl trimethicone 7.0
(8) Hydrogenated castor oil hydroxystearate 1.0
(9) Sucrose stearate (HLB: 5) *5 1.0
(10) Behenyl alcohol *6 2.0
(11) Stearyl alcohol *23 1.0
(12) Cetyl alcohol *24 0.5
(13) Fragrance, appropriate amount (Part B)
(14) Purified water remaining amount (15) Xanthan gum 0.4
(16) Sodium hyaluronate 0.1
(17) Diglycerin 2.0
(18) Dipropylene glycol 10.0
(19) 1,3-Butylene glycol 2.0
(20) Methylparaben 0.3
(21) Sodium stearoyl methyl taurate *10 0.3
(22) Polyglyceryl-10 diisostearate *11 3.0
(23) Polyquaternium-39 10% aqueous solution 0.5
(24) Green tea extract 0.2
Total 100.0
*27: Eusolex OCR (manufactured by Merck)
*28: TINOSORB S (manufactured by BASF)
*29: PARSOL 1789 (manufactured by DSM)

(Manufacturing method)
1. Heat Part A to 70°C and mix until uniform.
2. Heat part B to 70°C and mix it uniformly, then mix parts A and B together and cool to 35°C.

Example 41 Oil-in-water type daytime moisturizing cream (ingredient name) Weight (%)
(Part A)
(1) Dimethyl PABA ethylhexyl *30 10.0
(2) Diethylaminohydroxybenzoyl hexyl benzoate *31 2.0
(3) Oxybenzone-3*32 0.5
(4) Alkyl benzoate (C12-15) 7.0
(5) Isotridecyl isononanoate 9.0
(6) Sucrose stearate (HLB: 5) *5 1.3
(7) Stearyl alcohol *23 2.3
(8) Fragrance, appropriate amount (Part B)
(9) Purified water Remaining amount (10) Xanthan gum 0.43
(11) Sodium hyaluronate 0.05
(12) Glycerin 5.0
(13) 1,3-Butylene glycol 12.0
(14) Methylparaben 0.2
(15) Sodium stearoyl methyl taurate *10 0.5
(16) Polyglyceryl-10 diisostearate *11 2.5
Total 100.0
*30: Escalor 507 (manufactured by Bantyk)
*31: Uvinul A Plus Granular (manufactured by BASF)
*32: SEESORB 101 (manufactured by Cipro Chemical Co., Ltd.)

(Manufacturing method)
1. Heat Part A to 70°C and mix until uniform.
2. Heat part B to 70°C and mix it uniformly, then mix parts A and B together and cool to 35°C.

According to the present invention, it is possible to provide an oil-in-water emulsion sunscreen cosmetic that is non-sticky due to UV absorbers, has a smooth texture, and exhibits good stability over time.

Claims (3)

An oil-in-water emulsion sunscreen cosmetic containing the following ingredients (A) to (E).
(A) 0.5 to 2.0% by weight of sucrose stearate
(B) 0.05 to 1.0% by weight of sodium stearoyl methyl taurate
(C) 1.0 to 5.0% by weight of one or more higher alcohols selected from cetyl alcohol, stearyl alcohol, and behenyl alcohol (D) 1.5 to 5.0% by weight of polyglyceryl-10 diisostearate
(E) 3.0 to 18.0% by weight of UV absorber The oil-in-water emulsion sunscreen cosmetic according to claim 1, characterized in that the HLB value of the sucrose stearate ester of component (A) is 3 to 7. The oil-in-water emulsion sunscreen cosmetic according to claim 1 or 2, characterized in that 50% by weight or more of the higher alcohols of component (C) is behenyl alcohol.