KR20220043395A - Sunscreen base composition with excellent ultraviolet rays protection effect - Google Patents

Abstract

The present invention relates to a sunscreen base composition having an excellent UV screening effect and, more specifically, to a sunscreen base composition in which a gelling phenomenon does not occur by treating fine particles of titanium dioxide with alkyltriethoxysilane represented by chemical formula 1 and dispersing the titanium dioxide as nanoparticles in silicon using a high pressure dispersing device, and which has excellent feeling of use and an excellent UV screening effect, and to a sunscreen formulation cosmetic product manufactured using the base and having excellent UV protection index, feeling of use, and transparency.

Description

Sunscreen base composition with excellent ultraviolet rays protection effect

An object of the present invention is to provide a sunscreen base that treats fine titanium dioxide with alkyltriethoxysilane and disperses it as nanoparticles in a dispersion medium, thereby preventing gelling and exhibiting excellent usability and transparency.

Another object of the present invention is to provide a UV-blocking cosmetic that treats fine titanium dioxide with alkyltriethoxysilane and disperses it as nanoparticles in a dispersion medium, thereby preventing gelling and exhibiting excellent usability and transparency.

Sunlight is a part of daily life and is thought to be beneficial to health. However, with prolonged exercise or outdoor leisure activities such as swimming, golf, tennis, etc., excessive sun exposure of the skin is harmful and can cause dermatitis and even skin cancer. In particular, inorganic salts (titanium oxide, zinc oxide, etc.) have been widely used as UV scattering agents for a long time to protect human skin from harmful UV regions. However, when the fine particle titanium dioxide is used in high concentration, the feeling of use is bad, and there are disadvantages in that the skin becomes cloudy and the transparency is lowered.

Particulate titanium dioxide is used in paints, cosmetics, and chemical fibers as a sunscreen with high safety, stability and transparency. In particular, it is widely used in sunscreen products in the cosmetic field because of its ability to shield UV rays while being relatively transparent. Recently, in the Japanese market, the cosmetics market with a high UV protection index is growing. The amount of organic sunscreen used in cosmetics is limited. In this situation, the amount of particulate titanium dioxide in the formulation is continuously increasing. Most particulate titanium dioxide is dispersed in oil such as silicone, which is a material with excellent water repellency, chemical resistance and weather resistance.

Since the surface of fine particle titanium dioxide exhibits hydrophilicity, aggregation occurs strongly when dispersed in lipophilic silicone, and the original transparency or UV shielding effect is halved.

Numerous studies have been conducted to overcome these shortcomings. First, recently, for use as a sunscreen base with excellent safety, stability, and transparency, coated fine particles of titanium dioxide are dispersed in silicone and then redispersed using a sand mill or turbo mill to develop a sunscreen base with excellent transparency and usability. Research is being actively conducted (WO 9816193).

In general, as a result of dispersing the pretreated sample using a general homogenizer, the dispersibility is poor and precipitation occurs. As a result of dispersion using a sand mill, etc., the high shear homogenizer has excellent dispersibility and is competitive in price, but it has problems such as contamination of iron and long working time. The high pressure homogenizer has the disadvantage that the equipment is relatively expensive, but it has the advantages of good productivity, the best dispersing ability, and short working time.

Second, it is a study to modify the surface of particulate titanium dioxide in order to suppress the photocatalytic activity of the particulate titanium dioxide and increase compatibility with the dispersion medium. Oxides such as alumina and silica are coated on the particle surface (JP 63045123) as a surface treatment agent, or silicones other than inorganic materials (US 5756788) are used. This surface treatment greatly affects the dispersibility of resins, etc. and the feeling of use in addition to imparting light resistance. In the case of particulate titanium dioxide treated with an excessive amount of gold (aluminum stearate, aluminum laurate) to increase usability and transparency, gelling occurs when dispersed in oil. Particulate titanium dioxide coated with methicone has advantages such as giving a matte feeling when dispersed in oil, but when moisture is added to the sunscreen formulation, methicone reacts with water to generate hydrogen gas, which changes over time. .

Overcoming the disadvantages of the prior art as described above, the gelling phenomenon does not occur and leads to the manufacture of a base excellent in feeling of use and UV blocking effect.

As described in detail above, as a result of dispersing the fine particle titanium dioxide coated with the alkyltriethoxysilane of the present invention as nanoparticles in the dispersion medium using a high-pressure dispersing device, no gelling phenomenon occurs and excellent feeling of use and UV blocking effect A sunscreen base showing As a result of manufacturing by applying this base to sunscreen products, a product with excellent transparency, high UV index, and natural feeling of use was manufactured.

The present invention treats particulate titanium dioxide with alkyltriethoxysilane and disperses the titanium dioxide as nanoparticles in silicon using a high-pressure dispersing device, thereby preventing gelling and providing excellent feeling of use and UV blocking effect, and production of the same it's about how

The present invention also relates to a cosmetic composition having excellent UV protection index, usability, and transparency prepared by using the above sunscreen base in a sunscreen formulation.

Hereinafter, the present invention will be described in more detail.

Coating of fine particle titanium dioxide with alkyltriethoxysilane Add 530 g of fine particle titanium dioxide to 3L of purified water in a 5L reactor, stir and disperse using an azi mixer or a homomixer, while maintaining the reaction temperature at 100℃. After reacting by adding silane (Formula 1) at a concentration of 0.01-30% by weight, it was cooled to room temperature, and the surface of the fine particle titanium dioxide was coated with alkyltriethoxysilane. After washing and drying the particulate titanium dioxide coated with alkyltriethylsilane in this way, it is dried in air at a temperature increase rate of 5°C/min at 110°C for 2-4 hours. Thereafter, it was pulverized with a hammer mill to prepare coated particulate titanium dioxide.

[Formula 1]

In the above formula,

R1 is C3 -C22 alkyl,

R2 is C1-C22 alkyl.

That is, the present invention contains 30 to 70% by weight of a dispersion medium, 0.0001 to 20% by weight of a dispersant, and 10 to 60% by weight of particulate titanium dioxide coated with alkyltriethylsilane, and a high-pressure dispersing device is used as a dispersing device using the components. It relates to a base for blocking ultraviolet rays manufactured by

In the present invention, (a) the dispersion medium is liquid paraffin, triglycerin, squalane, olive oil, silicone oil, and the like. It is one type or a mixture of two or more types selected from among them. The most representative is decamethylcyclopentasiloxane (DC 345, SF 1202, etc.).

(B) The dispersant is a non-surfactant having an HLB of 3-10, and is one or a mixture of two or more selected from polyglycerol fatty acid ester, sorbitan fatty acid ester, silicone surfactant, and polyglucoside. The most representative example is a silicone surfactant.

(C) The content of alkyltriethoxysilane in the coated fine particle titanium dioxide may be 0.01-30% by weight, and preferably 3-20% by weight in consideration of the usability and stability of cosmetics. When the content of the alkyltriethoxysilane is 0.01 wt% or less, it is difficult to effectively coat the particulate titanium dioxide, and when the content is 30 wt% or more, the particulate titanium dioxide content is significantly reduced, so that the UV blocking ability is remarkably reduced.

Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited only to these examples.

Preparation of the base composition

Example 1 and Comparative Examples 1-3 are preparation examples of preparing a sunscreen base composition having the following composition components, respectively.

[Table 1]

Example 1 is an alkyltriethoxysilane-coated particulate titanium dioxide (35% by weight), cyclomethicone (55% by weight), and cetyldimethicone polyol (10% by weight) using an azi mixer, followed by a high-pressure dispersion device was dispersed using

Comparative Example 1 and Comparative Example 2 were prepared in the same manner as in Example 1.

Comparative Example 3 was prepared by dispersing using the same pretreatment process as Example 1 and using a general homomixer.

Experimental Example 1: Measurement of Base Particle Size

Particle size measurement: It was measured using a particle size analyzer (Malvern).

The particle size of the base in which particulate titanium dioxide is dispersed in silicon is as follows.

[Table 2]

The base of Example 1 did not cause gelling and exhibited an excellent feeling of use. The particle size is about 160 nm. In Comparative Example 1, when particulate titanium dioxide coated with aluminum stearate was used, the viscosity of the system rapidly increased during the pretreatment process or when a high-pressure dispersing device was used, resulting in gelling. As a result of preparing the pretreated sample using a high-pressure dispersing device, the gelling does not come off. This phenomenon is dependent on the amount of coated aluminum stearate. This phenomenon occurs when the amount of aluminum stearate is 10% or more. Because of this gelling phenomenon, it is impossible to manufacture sun products such as sun milk or sun cream.

Comparative Example 3 was dispersed using a general homomixer without using a high-pressure dispersing device. As a result, dispersibility was poor, so it was impossible to use.

In stability over a long period of time, many precipitation phenomena were observed. From the above experiment, it can be seen that Example 1 is superior to Comparative Example 3 in terms of usability, transparency, and product stability.

Preparation of a cosmetic comprising a base composition

Using Example 1, sun milk (Example 2) and sun cream (Example 3) were prepared.

Using Comparative Example 2, sun milk (Comparative Example 4) and sun cream (Comparative Example 5) were prepared.

The manufacturing method is as follows.

First, the oily component 1 is dissolved by heating it to 70-75 O C. Add oily component 2 to oily component 1 and sufficiently stir. The stirred aqueous component is slowly added dropwise to the oily component, emulsified, and cooled to room temperature.

[Table 3]

Experimental Example 2: Measurement of UV protection index

Example 2, Example 3, Comparative Example 4 and Comparative Example 5 UV protection index measurement method is as follows.

Test subjects: 9 (7 male, 2 female)

Test site: Left and right parts excluding the vertebral part of the back

Light source: ORIEL Solar Simulator 81293 (Xenon UV Lamp 1kW, unfiltered)

Photometer: IL1700 Radiometer, SED 240 probe

Sun Protection Factor (SPF) Measurement

The amount of ultraviolet light emitted from the solar simulator lamp to the test site was adjusted to 20-100 mJ/cm 2 and irradiated on the subject's back. After 24 hours of irradiating ultraviolet light, the minimum amount of erythema (MED) was confirmed.

In order to confirm the UV blocking effect of the sample, the sample was uniformly applied to the back of the test subject with a thickness of 2 μl/cm 2 and left for 15 minutes to dry. An ultraviolet irradiation window was attached to each sample application site and fixed, and ultraviolet rays were irradiated while blocking ultraviolet rays using leather and towels in other areas except for the irradiation window.

Based on the subject's MED, the SPF 50 predicted sample was tested with SPF 15-40, and the SPF100 predicted sample started with an irradiation dose up to SPF 40-65 and gradually increased the UV radiation dose. After 24 hours of UV irradiation, the minimum amount of erythema was determined, and the UV blocking effect of the sample was calculated according to the formula below.

The results of measuring the UV blocking effect (SPF) of Examples 2, 3, Comparative Examples 4 and 5 are as follows.

[Table 4]

From the above, it can be seen that Examples 2 and 3, which are cosmetics prepared by Example 1, which is the base of the present invention, in which fine particle titanium dioxide coated with alkyltriethoxysilane is dispersed as nanoparticles in a dispersion medium, exhibits excellent UV protection effect. there is. In addition, cosmetics prepared with a base containing dimethicone-coated particulate titanium dioxide also had excellent UV protection effects.

However, as a result of observing the viscosity and feeling of use over a long period of time, in the cosmetics (Comparative Examples 4 and 5) prepared with the base containing dimethicone-coated particulate titanium dioxide, the aggregation of particles increased, resulting in increased viscosity and improved feeling of use. has been lowered In addition, methicone reacted with water to generate hydrogen gas, which caused the tube container to swell. On the other hand, the cosmetics (Examples 2 and 3) prepared with a base containing fine particle titanium dioxide coated with alkyltriethoxysilane did not have agglomeration of particles, so the viscosity was maintained and the feeling of use was maintained. In addition, since hydrogen gas is not generated in the tube container, there is no swelling of the tube container.

[Table 5]

Claims (8)

In the UV blocking base composition comprising particulate titanium dioxide, a dispersion medium and a dispersing agent, the particulate titanium dioxide is coated with an alkyltriethoxysilane of Formula 1, and the coated particulate titanium dioxide is dispersed in a dispersion medium in a nano-particle size A sunscreen base composition with excellent UV blocking effect.
[Formula 1]

In the above formula,
R1 is C3 to C22 alkyl,
R2 is C1 to C22 alkyl. The sunscreen base composition of claim 1, wherein the dispersion medium is a single substance or a mixture of two or more selected from the group consisting of liquid paraffin, triglycerin, squalane, olive oil, silicone oil, and decamethylcyclopentasiloxane. . According to claim 1, wherein the dispersant is a non-surfactant with an HLB of 3-10, which is a single substance or a mixture of two or more selected from the group consisting of polyglycerol fatty acid ester, sorbitan fatty acid ester, silicone surfactant, and polyglucoside. A sunscreen base composition with excellent blocking effect. [Claim 2] The sunscreen base composition with excellent UV protection effect according to claim 1, wherein the fine particle titanium dioxide coated with alkyltriethoxysilane is dispersed in an amount of 10 to 60 wt% based on the total base composition. [Claim 5] The sunscreen base composition of claim 4, wherein the content of alkyltriethoxysilane in the coated fine particle titanium dioxide is 0.01 to 30% by weight. [Claim 6] The sunscreen base composition according to any one of claims 1 to 5, wherein the particulate titanium dioxide coated with alkyltriethoxysilane is dispersed in a dispersion medium using a high-pressure dispersing device. A cosmetic for UV protection comprising the base composition for blocking UV according to any one of claims 1 to 6. The cosmetic according to claim 7, wherein the sunscreen base composition is contained in an amount of 1 to 70% by weight of the total cosmetic amount.