KR100835865B1 - Microfine emulsion containing titanium dioxide and zinc oxide and composition of external application to the skin containing thereof - Google Patents

Abstract

The present invention relates to an oil dispersion in which titanium dioxide and zinc oxide, which are inorganic substances, are stably dispersed at a high concentration in a dispersion medium, a preparation method thereof, and an external preparation composition containing the same.

Inorganic UV Blocker * Dispersion * Stabilization * Titanium Dioxide * Zinc Oxide

Description

Microdispersion of titanium dioxide and zinc oxide and composition for external application containing the same

1 is a graph showing the particle size distribution change and stability with respect to time of the oil dispersion prepared in Examples 1 to 4 measured by the dynamic laser light scattering method.

2 is a graph showing particle size comparison and stability with time of the oil dispersions prepared in Examples 6 and 7 measured by dynamic laser light scattering.

The present invention relates to an oil dispersion in which titanium dioxide and zinc oxide, which are inorganic substances, are stably dispersed at a high concentration in a dispersion medium, a preparation method thereof, and an external preparation composition containing the same.

As the effect of UV rays on the skin is known, the trend of anti-UV cosmetics in the past has been to protect against UV rays in daily life, in the direction of preventing sun burn, ie, excessive sun exposure, in leisure activities. It is changing in the direction which suppresses generation | occurrence | production of a blemish, freckles, and wrinkles.

The material having the ultraviolet protective function can be classified into an organic ultraviolet absorber which absorbs ultraviolet rays and converts energy into heat, waves, fluorescence and radicals, and an ultraviolet scattering agent which is an inorganic pigment that absorbs and scatters ultraviolet rays.

Organic UV absorbers mainly used to defend UVB (290-320 nm), so the main purpose was to defend UVB rather than UVA (320-400 nm). Organic ultraviolet absorbers have high absorption coefficients and efficiently absorb ultraviolet rays, but degradation and polymerization occur after absorption, resulting in poor skin safety and sustainability of UV blocking. Therefore, these problems are followed by limitations of ingredients and concentrations.

Inorganic sunscreens are mainly composed of metal oxides, and have a high refractive index, so the light scattering effect is high, and since they are inorganic, there are few problems such as decomposition such as organic UV absorbers. However, because of the visible light dispersion, white is conspicuous, and natural makeup is difficult, and there is a disadvantage that a feeling of flutter occurs when the skin is applied.

These UV absorbers and scattering agents all have advantages and disadvantages, but among them, inorganic UV blockers having high UV protection at a broad wavelength and having high safety may play an important role in UV blocking.

As such, the inorganic sunscreen is generally defined as an ultraviolet scattering agent because the UV protection effect due to the scattering of ultraviolet light is large, whereas the organic ultraviolet ray blocking agent is defined as an ultraviolet absorber.                         

Titanium dioxide or zinc oxide, which is an inorganic sunscreen, is defined as a white pigment in the classification of pigments, and is a pigment having a high sealing force due to light scattering, and their light scattering power depends on refractive index and particle size.

Recent studies show that when UV is irradiated, titanium dioxide and zinc oxide are excited from the low energy state (valence band) to the high energy state (conduction band). This case occurs when the incident excitation energy UV is larger than the energy gap. The energy gap here refers to the amount of energy required to excite the electrons of titanium dioxide and zinc oxide. Rutile titanium dioxide has an energy gap of 3.06 eV and for zinc oxide has an energy gap of 3.23 eV. According to Equation 1 below, since titanium dioxide corresponds to a wavelength of 405 nm and zinc oxide is 385 nm, titanium dioxide absorbs ultraviolet rays shorter than 405 nm and zinc oxide absorbs ultraviolet rays shorter than 385 nm. . This is because the wavelength and energy of light are inversely proportional. Titanium dioxide, on the other hand, scatters ultraviolet rays longer than 405 nm and zinc oxide scatters ultraviolet rays longer than 385 nm.

* lambda = wavelength

h = Planck's constant

* C = speed of light

* E = energy gap

The absorbed energy is converted into a longer wavelength (visible light, etc.) as the electrons are lowered to a low energy state.

On the other hand, titanium dioxide and zinc oxide show little absorption in the visible light region of 400 nm or more.

Therefore, the use of titanium dioxide and zinc oxide as UV blocking powders was previously due to high UV blocking ability due to high refractive index, but in recent years, UVA and UVB have absorption ability in the UV region and no visible ability in the visible region. It is recently discovered that it is a colorless powder.

Features of the inorganic sunscreen are as follows.

First of all, firstly, it has the blocking function in the whole UV area of UVA and UVB, and secondly, it is chemically stable, thirdly, it is not toxic and high in safety, and fourthly, it is odorless. On the other hand, the disadvantages are: first, white is conspicuous in order to disperse visible light, making natural finish of makeup difficult; second, heavy spreading, a feeling of fluffing when applied to the skin; and third, light activity when particulated. high.

Therefore, it is important to develop a material that improves these disadvantages while taking advantage of these advantages.

For this reason, researches for satisfying high transparency and usability, such as development of techniques such as pigment fineness, texture improvement, and complexation, have been continuously conducted. In addition, the development of formulations in consideration of the dispersibility and persistence of inorganic pigments is also important with material development.

Titanium dioxide or zinc oxide, developed as an inorganic sunscreen, has many functional and operational difficulties in its formulation, despite its UV-shielding effectiveness over a wide range of wavelengths.

Generally, physically developed inorganic sunscreens such as titanium dioxide and zinc oxide are called 'microfine' and generally have a diameter of less than 1 um.

Submicron particles of less than 1um are not only effective in blocking ultraviolet rays but also scattering light (visible light). Therefore, it is useful in the application of sun care products, such as basic cosmetics and makeup cosmetics. However, particles larger than 1 μm scatter light in the visible region, causing a so-called whitening effect.

However, microfine titanium dioxide has high photoactivity due to its large specific surface area. Therefore, when formulated in cosmetics, not only the quality of the cosmetics may be lowered, but may also cause skin irritation when applied to the skin. In general, particulate titanium dioxide produces negatively charged electrons and positively charged holes when exposed to light. These electrons and holes have very strong reducing and oxidizing power to generate hydroxyl groups (OH) and peroxygen ions (O ₂ ⁻ ), which are active oxygen, from water and oxygen in the atmosphere. Therefore, titanium dioxide, which is used as a raw material for cosmetics, is mostly surface treated to prevent such photoactivity. Surface treatment materials include surface treatment using alumina, silica, zirconium or metal soap treatment.

In addition, these sub-micron-sized particles have several problems.

That is, titanium dioxide or zinc oxide forms primary particles to easily form agglomerates during the manufacturing process such as drying or crushing the particles or during storage or various processes. These associations again associate with each other to form larger particles, which are called 'clumps'. Such clumps generally have a particle size much greater than 1 um. Eventually, these associations reduce the inherent sunscreen function of titanium dioxide and zinc oxide and increase the cloudiness when applied over the skin. 'Microfine' particles are associated with each other and gradually produce 'agglomeration' or 'dusting', which do not exhibit UV protection.

Titanium dioxide is divided into pigment grade titanium dioxide having a primary particle size of 200 to 300 nm and particulate titanium dioxide having a particle size of less than 100 nm because of the difference in particle size. Compared with pigment grade titanium dioxide, particulate titanium dioxide has increased transparency in the visible light region. Pigment-grade titanium dioxide has a relatively high hiding power, and fine particle titanium dioxide of 100 nm or less has a high scattering ability in the visible light region, thereby increasing transparency and increasing ultraviolet defense ability. There are two structures of titanium dioxide, anatase and rutile, and the physical differences according to the crystal structure and its crystal structure are as follows.

Anatas is a crystal in which crystal units are connected with vertices (point contact), and rutile is a crystal shape in which crystal units are connected with side edges (line contact), and their properties are compared in Table 1 below.

Comparison of Properties According to the Structure of Titanium Dioxide Anatas Rutile color Dark brown, yellow, blue Black, Reddish Brown (Coarse Crystals) Yellow (Thin Crystal) transparency opacity Transparency decision Tetragonal Tetragonal Hardness 5.5 to 6 6 to 6.5 Striped color White Brown importance 3.8 to 3.9 4.2 Band Gap Energy 3.23 eV 3.02 eV Where to use Photocatalyst material White paint, pigment

The ability to block UV rays consists of a complex mechanism of scattering and absorbing UV rays. In the short wavelength ultraviolet light, the effect is mainly due to absorption, while in the long wavelength ultraviolet light, the dispersing function is dominant. Particle size exists to effectively exhibit both absorption and dispersion effects in the ultraviolet ray shielding of particulate titanium dioxide, which is known to be about 70-190 nm. In addition, various surface treatments such as silicon, metal soap, fluorine compound, silica, and alumina are performed to improve dispersibility of fine particle titanium dioxide, suppress photocatalytic reaction, improve skin contact, improve water resistance, and improve oil repellency. In dispersibility, fine particles of 100 nm or less often form secondary aggregation. Such agglomerates exhibit the behavior of titanium dioxide having a large particle size, and thus cannot exhibit the expected sunscreen effect. The formation of these particles produces 'agglomeration' or 'dusting', which adversely affects the cosmetics containing them, and also reduces the stability of the cosmetics and the stability of the formulation during storage. . As described above, 'agglomeration' and 'dusting' due to the growth of inorganic particles for UV protection are crucial factors in formulating and blocking UV rays of inorganic particles, which are effective sunscreens. Techniques for preventing particle aggregation such as 'agglomeration' and 'dusting' are essential for developing effective inorganic sunscreens. Therefore, high dispersion and stability of dispersion state are important keys. That is, as a surface treatment for enhancing the dispersibility in the dispersion medium, a technique for surface treatment using aluminum stearate or the like to improve dispersibility in the oil phase or silica or hydrophilic polymer to increase the dispersibility in the water phase Developed.

Although various dispersion systems have been developed, a stable dispersion system has not been developed that can be applied to various sun formulations such as lotions, creams, sprays, and personal hand creams and body creams. In addition, in order to prevent agglomeration of particles in the past, a high viscosity gel state using a high melting point ester oil or the like has been developed (US Patent No. 6,261,713). However, the dispersed particles in the dispersed state substantially shows a stable state of the particles at room temperature, but as the temperature increases, the aggregation of particles may occur due to the increase in the activity of molecular motion. Substantially, since the temperature during emulsification and solubilization during the preparation of the cosmetic formulation is usually at 70 to 80 ° C., agglomeration may occur due to the influence of the temperature of dispersed titanium dioxide or zinc oxide.

In addition, after dispersing the titanium dioxide in the dispersion medium, an appropriate dispersant was added and sufficiently stirred, and then a study was conducted to disperse the fine particles using a mill before use (US Patent No. 5,573,753).

In addition, a dispersion system has been developed that can contain 0.5 to 50% by weight of titanium dioxide relative to the weight of cosmetics by coating phospholipid on the surface of titanium dioxide, which can prevent the aggregation of particles to some extent by coating the surface of titanium dioxide with phospholipid Distributed system (US Pat. No. 5,817,298).

However, among these existing dispersion technologies, no studies showing stabilization techniques and changes over time for the dispersion system of inorganic sunscreens have been stable for a long time.

Accordingly, an object of the present invention is to develop a system capable of preventing agglomeration of titanium dioxide and zinc oxide, which are inorganic sunscreens, and to secure stability.

Accordingly, the present inventors have found that a stable dispersion system can be designed by identifying a relationship between a dispersion medium and a dispersant for preventing aggregation of titanium dioxide and zinc oxide particles, which are inorganic sunscreens, and completed the present invention.

Accordingly, it is an object of the present invention to design a stable dispersion system of inorganic sunscreens and to improve their stability to provide a stable oil dispersion having effective ultraviolet blocking ability.

It is still another object of the present invention to provide a method for preparing a low viscosity dispersed phase by adding an appropriate dispersant at an appropriate concentration in dispersing an inorganic sunscreen agent in a lipophilic solvent.                         

Another object of the present invention is to provide a method for producing an inorganic sunscreen in a lipophilic solvent as a dispersion medium to reduce the particle size through a continuous high pressure, high speed mill to produce a size of several tens to hundreds of nanometers.

Accordingly, it is an object of the present invention to provide a skin external preparation composition containing an oil dispersion containing the above stable inorganic sunscreen agent.

The present invention provides a sunscreen oil dispersion in which an inorganic sunscreen is dispersed and a method for producing the oil dispersion.

The present invention also relates to a sunscreen and stabilization technology using the oil dispersion.

In addition, the present invention provides an external composition for sunscreen containing the stabilized oil dispersion. Preferably, the sunscreen of the invention is titanium dioxide or zinc oxide. In the present invention, titanium dioxide or zinc oxide, which is a UV blocking component, is coated with inorganic and organic materials to prevent photoactivity, and an oil dispersion in which particles of an inorganic UV blocking agent are dispersed has a low viscosity at room temperature and thus shear force. The addition is characterized by the characteristic of a typical thixotropic structure in which the viscosity decreases.

In addition, the oil dispersion containing the inorganic particles is characterized in that the initial particle dispersion state is maintained for about 6 months.

The process for producing the oil dispersion of the inorganic sunscreen of the present invention consists of the following steps.

First, adding a suitable dispersant to the dispersion medium, followed by stirring to maintain a constant concentration to form a lipophilic phase; A wet process and a dispersion step of adding and stirring an inorganic sunscreen to the lipophilic phase to wet the inorganic sunscreen in the lipophilic phase and simultaneously milling with beads for shrinking the particles; Separating the inorganic sunscreen dispersion dispersed in the second step from the beads; A steady state step of stirring so that the concentration of the inorganic sunscreen is constant after separation; And separating and stabilizing the aggregated particles by applying high energy after reaching a steady state in which the inorganic sunscreen is formed at a constant concentration on the surface of the inorganic sunscreen by forming a constant mixing with the dispersion medium.

The oil dispersion contains 0.1 to 70% by weight of an inorganic sunscreen. For example, titanium dioxide may contain 0.1 to 60% by weight, preferably 20 to 50% by weight, and zinc oxide to 0.1 to 70% by weight, preferably 30 to 60% by weight. Moreover, these can be mixed and used. If it is less than 0.1% by weight can not have the expected effect, whereas if it exceeds 70% by weight there is a problem that the dispersion is not performed properly.

In addition, an ester oil or a silicone oil may be used as the dispersion medium of the present invention.

The amount of the dispersant added in the present invention is characterized by containing 0.1 to 20% by weight, preferably 2 to 15% by weight of the total weight of the total oil dispersion. If it is less than 0.1% by weight, the expected effect cannot be obtained, and if it exceeds 20% by weight, there is a problem that formulation is difficult.                     

For example, the manufacturing method of the oil dispersion of the micro titanium dioxide of this invention is demonstrated in detail as follows.

First, a suitable dispersant is added to the dispersion medium, followed by sufficient stirring for 2 to 3 hours at a speed of 50 to 200 rpm to maintain a constant concentration. Agitation uses a common mixer, such as a paddle mixer. In addition, when the baffle (baffle) is installed in the reactor, the mixing can be made smoothly. Secondly, titanium dioxide is added to the lipophilic phase at 0.1 to 60% by weight based on the total weight and stirred for a sufficient time to wet the titanium dioxide in the lipophilic phase. In this step, milling with beads is applied to wet and simultaneously shrink the particles. Beads generally use zirconium with low impact and low wear. The size of the beads is appropriately about 10-30mm. It is appropriate that the input amount of beads is 2 to 3: 1 by volume ratio of oil dispersion and beads. Third, the titanium dioxide dispersion dispersed in the second step is separated from the beads. After separation, agitation was performed in a secondary manner so that the concentration of titanium dioxide was constant. This is done in the same way as the first step. Fourth, the titanium dioxide is a constant mixing with the dispersion medium, so that the dispersant is adsorbed at a constant concentration on the surface of the titanium dioxide. After reaching this steady state, high energy is added to separate and stabilize the aggregated particles.

In the first and second steps of the manufacturing method, the dispersant may be first mixed with the dispersion medium and the inorganic sunscreen component may be added, and the inorganic sunscreen component may be added to the dispersion medium, and then the dispersant may be added to facilitate the wetting and dispersing. It may be. Preferably, the dispersant is first added to the dispersion medium, followed by further addition of the inorganic sunscreen component.

As a method of applying high energy, devices such as dynomil and microfluidics (Microfluidics. Inc.) may be used. These high energy dispersers can be largely divided into batch type and continuous type. Considering the efficiency and economics of the process, continuous is better than stationary, but in the case of continuous the efficiency of dispersion and particle reduction must be taken into account.

Through these various steps, it is possible to prepare a dispersion of transparent fine particles of an inorganic sunscreen which maintains a particle size of several tens to hundreds of nanometers, and the present invention provides such inorganic sunscreens such as titanium dioxide and zinc oxide. It is characterized by a method for producing a fine oil dispersion.

The titanium dioxide, zinc oxide, dispersion medium and dispersant presented in the present invention are shown in Table 2 below.

Ingredient (trade name) INCI source Dispersion Finsolv TN C12-15 Alkyl Benzoate Fintex Inc. ININ Iononyl Isononanoate DUBIOS Inc. IPM Iso propyl myristrate ODO Octyl Dodecyl Oleate DC345 Cyclo Methicone Dow Corning Titanium dioxide M170 Titanium dioxide / aluminum oxide / demethicone Kemira Inc. TTO S-2 Titanium dioxide / aluminum hydroxide / zirconium oxide / stearic acid Ishihara Sangyo Kaisha Ltd. Zinc oxide Zinc oxide Zinc oxide / dimethicone Seokkyung Co., Ltd. Dispersant Abil EM 90 Cetyl PEG / PPG EMALEX SS 5050 Polyoxyethylene-MethylpolySiloxane copolymer Nihon Emulsion Co.Ltd. Hexaglyn PR-15 Poly hexaglycerin recinolate NIKKO Chemical Co., Ltd.

The combination of the dispersing agent and dispersion medium which form a stable oil dispersion with respect to the said inorganic type sunscreen is as follows.

First, in the case of using titanium dioxide, Hexaglyn PR-15 is preferred as a dispersion medium and a dispersant of an ester oil in the case of titanium dioxide M170, and EMALEX SS5050 is preferred as a dispersion medium and a dispersant of a silicone oil in the case of titanium dioxide TTO S-2. .

In addition, when using zinc oxide, both ester oil-Hexaglyn PR-15 and silicone oil-EMALEX SS5050 are preferable.

The finely divided titanium dioxide and zinc oxide oil dispersion of the present invention used titanium dioxide and zinc oxide whose surface was treated with inorganic or organic materials to prevent photoactivity.

The surface treatment material is composed of a lipophilic coating material suitable for the dispersion medium is lipophilic. Typical organic coating materials include silicone-based coatings such as dimethyldimethoxysilane, dimethicone, methicone, polysiloxane, and fatty acids such as stearic acid, oleic acid, and linoleic acid, and inorganic coating materials such as aluminum hydroxide and zirconium.

In addition, the external preparation composition of the present invention is characterized by containing the sunscreen dispersion dispersed in fine particles in an amount of 0.1 to 60% by weight based on the total weight of the composition.

The external composition using the fine dispersion of titanium dioxide and zinc oxide of the present invention is not particularly limited in the formulation, for example, softening longevity, nourishing longevity, massage cream, nourishing cream, pack, gel or skin adhesive type It may be a cleaning composition such as cosmetics, shampoos, rinses, body cleansers, soaps, and the like having cosmetic formulations such as cosmetics, lipsticks, makeup bases, foundations, and the like, and also, transdermals such as lotions, ointments, gels, creams, patches or sprays. Dosage forms.

Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited to this.

Example 1 Finsolv TN Oil Dispersion of M170

40 g of polyhexaglycerin resinoleate (trade name: Hexaglyn PR-15, manufacturer: Nikko Chemical Co., Ltd., hereinafter referred to as 'Hexaglyn PR-15') as a dispersion medium C _12-15 alkylbenzoate (trade name: Finsolv) TN, manufacturer: Fintex Inc. (hereinafter referred to as Finsolv TN)) was added to 240 g and stirred at a rate of 50 to 200 rpm for 2 to 3 hours to maintain a constant concentration. 120 g of titanium dioxide (trade name: M170, manufacturer: Kemira, hereinafter referred to as 'M170') was added thereto. In order to maintain a constant concentration was stirred using a paddle mixer to ensure that M170 was constantly mixed in the dispersion medium. At this time, by installing a blocking membrane in the reactor to cause turbulence it was possible to shorten the stirring time.

The ball mill was used to cause primary size reduction after stirring to allow wetting for a sufficient time. Zirconium beads used in the ball mill used a size of about 30 mm. The amount of beads added was such that the volume ratio of the oil dispersion and the beads was 2-3: 1.

Thereafter, the beads and the oil dispersion were separated and then stirred for 1 hour to uniformly adsorb the dispersant Hexaglyn PR-15 onto M170, and then fine dispersion was performed using a high pressure, continuous vertical mill. At this time, the beads used a size of about 3 ~ 5um. Precipitation of oil dispersion can occur after a long time after the first dispersion. Therefore, before the second microdispersion, stirring is carried out using a stirrer to maintain a constant concentration, and at the same time, the dispersant can be uniformly adsorbed onto titanium dioxide. .

Example 2 ININ Oil Dispersion of M170

40 g of Hexaglyn PR-15, a dispersant, was added to 240 g of isononyl isononanoate (trade name: ININ, manufactured by Dubios Inc., hereinafter referred to as 'ININ'), and stirred for 2 to 3 hours at a speed of 50 to 200 rpm. The concentration was made constant. 120 g of M170 was added thereto. In order to maintain a constant concentration was stirred using a paddle mixer to ensure that M170 was constantly mixed in the dispersion medium. At this time, it was possible to smoothly stir by installing a blocking membrane in the reactor to cause turbulence.

The ball mill was used to stir for a sufficient time and to cause first size reduction. Zirconium beads used in the ball mill used a size of about 30 mm. The amount of beads added was such that the volume ratio of the oil dispersion and the beads was 2-3: 1.

Thereafter, the beads and the oil dispersion were separated, and then stirred for 1 hour, and then microdispersion was performed using a high pressure, continuous vertical mill. At this time, the beads used a size of about 3 ~ 5um. Since a long time after the first dispersion may cause precipitation of the oil dispersion, the concentration was kept constant by stirring using a paddle stirrer before performing the second microdispersion.

Example 3 IPM Oil Dispersion of M170

40 g of Hexaglyn PR-15 as a dispersant was added to 240 g of isopropylmyrilate (trade name: IPM, hereinafter referred to as 'IPM') as a dispersion medium, and stirred at a speed of 50 to 200 rpm for 2-3 hours to keep the concentration constant. 120 g of M170 was added thereto. In order to maintain a constant concentration was stirred using a paddle mixer to ensure that M170 was constantly mixed in the dispersion medium.

The ball mill was used to cause primary size reduction after stirring for sufficient time to cause the wetting. Zirconium beads used in the ball mill used a size of about 30 mm. The amount of beads added was such that the volume ratio of the oil dispersion and the beads was 2-3: 1.

Thereafter, the beads and the oil dispersion were separated, and then stirred for 1 hour, followed by fine dispersion using a high pressure, continuous vertical mill. At this time, the beads used a size of about 3 ~ 5um. Since a long time after the first dispersion may cause precipitation of the oil dispersion, the concentration was kept constant by stirring using a paddle stirrer before performing the second microdispersion.

Example 4 ODO Oil Dispersion of M170

40 g of Hexaglyn PR-15 as a dispersant was added to 240 g of octyldodecyl oleate (trade name: ODO, hereinafter referred to as 'ODO') and stirred at a speed of 50 to 200 rpm for 2-3 hours to maintain a constant concentration. 120 g of M170 was added thereto. At this time it was added to the ODO to facilitate dispersion and wetting. In order to maintain a constant concentration was stirred using a paddle mixer to ensure that M170 was constantly mixed in the dispersion medium.

The ball mill was used to cause primary size reduction after stirring for sufficient time to cause the wetting. Zirconium beads used in the ball mill used a size of about 30 mm. The amount of beads added was such that the volume ratio of the oil dispersion and the beads was 2-3: 1.

Thereafter, the beads and the oil dispersion were separated, and then stirred for 1 hour, followed by fine dispersion using a high pressure, continuous vertical mill. At this time, the beads used a size of about 3 ~ 5um. Since a long time after the first dispersion may cause precipitation of the oil dispersion, the concentration was kept constant by stirring using a paddle stirrer before performing the second microdispersion.

Example 5 ININ Oil Dispersion of M170

120 g of M170 was added to 240 g of isononylisononanoate (trade name: ININ, manufactured by Dubios Inc., hereinafter referred to as 'ININ') with gentle stirring. M170 can be dispersed up to 60% by weight. At this time, 40g of Hexaglyn PR-15, a dispersant, was added to ININ to facilitate dispersion and wetting. In order to maintain a constant concentration was stirred using a paddle mixer to ensure that M170 was constantly mixed in the dispersion medium. At this time, it was possible to smoothly stir by installing a blocking membrane in the reactor to cause turbulence.

The ball mill was used to cause primary size reduction after stirring for sufficient time to cause the wetting. Zirconium beads used in the ball mill used a size of about 30 mm. The amount of beads added was such that the volume ratio of the oil dispersion and the beads was 2-3: 1.

Thereafter, the beads and the oil dispersion were separated, and then stirred for 1 hour, followed by fine dispersion using a high pressure, continuous vertical mill. At this time, the beads used a size of about 3 ~ 5um. Since a long time after the first dispersion may cause precipitation of the oil dispersion, the concentration was kept constant by stirring using a paddle stirrer before performing the second microdispersion.

Test Example 1 Comparison of Particle Size Analysis (Examples 1 to 3)

The dispersion state was measured by analyzing the size of particles in which titanium dioxide in each of Examples 1 to 3 was dispersed. The particle size distribution is an important factor because it directly affects the UV blocking ability, and also has the advantage of recognizing dispersion stability. The size and distribution of the particle size can be analyzed up to several nanometer particle size by dynamic light scattering (Zetasizer 3000HS, Malvern, UK). In Figure 1 it can be seen the particle size and stability results for each example.

As can be seen in Figure 1, the particle size distribution change of the dispersion with respect to time is showing a different aspect depending on the dispersion medium. The dispersion process of Examples 1 to 3 occurs smoothly, but shows a large difference in stability. It can be seen that the stability of the oil dispersion using the ININ as the dispersion medium in Example 2 is the most excellent. The particle size is about 160-190 nm, which is a range of particles that can effectively block ultraviolet rays.

Example 6 Silicone Oil Dispersion of TTO S-2 with Dispersant ABIL EM 90

As a dispersant, 48 g of cetyl PEG / PPG (trade name: ABIL EM90, hereinafter referred to as ABIL EM90), a typical silicone surfactant, was added to 212 g of cyclomethicone (trade name: DC345, hereinafter referred to as 'DC345') as a dispersion medium, and 50 to 200 rpm. The mixture was stirred at a rate of 2 to 3 hours to keep the concentration constant. 140 g of titanium dioxide (trade name: TTO S-2, manufacturer: Ishihara Sangyo Kaisha Ltd., hereinafter referred to as 'TTO S-2') was added thereto. In order to maintain a constant concentration by stirring using a paddle mixer, TTO S-2 was constantly mixed with the dispersion medium.

The subsequent process was carried out in the same manner as in Example 1.

Example 7 Silicone Oil Dispersion of TTO S-2 Using Dispersant EMALEX SS 5050

As a dispersant, 48 g of polyoxyethylene-methylpolysiloxane copolymer (trade name: EMALEX SS 5050, manufactured by Nihon Emulsion Co., Ltd., hereinafter referred to as EMALEX SS 5050), a typical silicone surfactant, was added to 212 g of DC345, a dispersion medium. It stirred at the speed of -200 rpm for 2-3 hours, and made concentration constant. 140 g of TTO S-2 was added thereto. In order to maintain a constant concentration by stirring using a paddle mixer, TTO S-2 was constantly mixed with the dispersion medium.

The subsequent process was carried out in the same manner as in Example 1.

Example 8 Silicone Oil Dispersion of TTO S-2 with Dispersant ABIL EM 90

140 g of titanium dioxide (trade name: TTO S-2, manufacturer: Ishihara Sangyo Kaisha Ltd., hereinafter referred to as 'TTO S-2') was slowly added to 212 g of cyclomethicone (trade name: DC345, hereinafter referred to as 'DC345') and stirred. It was. TTO S-2 can be dispersed up to 60% by weight. At this time, a dispersant was added to DC345 in order to facilitate dispersion and wetting. The dispersant was added 48 g of cetyl PEG / PPG (trade name: ABIL EM90, hereinafter referred to as 'ABIL EM90'), which is a typical silicone surfactant. In order to maintain a constant concentration by stirring using a paddle mixer, TTO S-2 was constantly mixed with the dispersion medium.

The subsequent process was carried out in the same manner as in Example 1.

Example 9 Silicone Oil Dispersion of TTO S-2 Using Dispersant EMALEX SS 5050

140 g of TTO S-2 was slowly added to 2345 g of DC345 and stirred. TTO S-2 was dispersed up to 60% by weight. At this time, a dispersant was added to DC345 in order to facilitate dispersion and wetting. The dispersant was added 48 g of polyoxyethylene-methylpolysiloxane copolymer (trade name: EMALEX SS 5050, manufactured by Nihon Emulsion Co., Ltd., hereinafter referred to as 'EMALEX SS 5050'), which is a representative silicone surfactant. In order to maintain a constant concentration by stirring using a paddle mixer, TTO S-2 was constantly mixed with the dispersion medium.

The subsequent process was carried out in the same manner as in Example 1.

Test Example 2 Comparison of Particle Size Analysis (Examples 6 and 7)

Examples 6 and 7 are stearic acid coated on the surface of titanium dioxide. In order to disperse this in the DC345, a silicone oil, a dispersant with a low HLB (hydrohhilic / lipophilic balance) value should be used. In addition, since the dispersion medium is a silicone oil, it is appropriate to use a silicone-based dispersant. Therefore, in the present invention, dispersion was performed using two ABIL EM 90 and EMALEX SS 5050, and the stability thereof was examined. In the case of ABIL EM 90, dispersion was well performed, but the viscosity of the oil dispersion rapidly increased as time passed. In the case of EMALEX SS 5050, the viscosity was maintained.

As a result of measuring particle size and stability of dispersed particles using dynamic light scattering (Zetasizer 3000HS, Malvern, UK), as shown in FIG. 2, the stability of the dispersion using EMALEX SS 5050 as a dispersant It can be seen that the particle size is much finer than the oil dispersion using ABIL EM 90 as a dispersant, and the stability is excellent.

The average particle size is about 160-190 nm, which satisfies the range with effective ultraviolet blocking.

Example 10 Ester Oil Dispersion of ZnO

48 g of Hexaglyn PR-15 as a dispersant was added to 152 g of Finsolv TN as an ester-based oil as a dispersion medium and stirred for 2 to 3 hours at a speed of 50 to 200 rpm to maintain a constant concentration. To this was added 200 g of zinc oxide surface-treated with dimethicone. In order to maintain a constant concentration was stirred using a paddle mixer to ensure that the zinc oxide is constantly mixed with the dispersion medium. At this time, by installing a baffle in the reactor to cause turbulence, the stirring time can be shortened.

The subsequent process was carried out in the same manner as in Example 1. The oil dispersion of zinc oxide showed a stable dispersion state in Finsolv TN and ININ, which are ester oils, unlike the oil dispersion of titanium dioxide. The average particle size was 150 to 180 nm.

Example 11 Silicone Oil Dispersion of ZnO

48 g of EMALEX SS 5050, a dispersant, was added to 112 g of DC345, a dispersion medium, and stirred at a rate of 50 to 200 rpm for 2-3 hours to maintain a constant concentration. To this was added 240 g of zinc oxide surface-treated with dimethicone. The subsequent process was carried out in the same manner as in Example 1. As a result of dispersion of zinc oxide, it showed stable dispersion state and the average particle size was 160 ~ 190nm.

Example 12 Ester Oil Dispersion of ZnO

200 g of zinc oxide treated with dimethicone was gradually added to 152 g of ININ, an ester oil, and stirred. Dimethicone treated zinc oxide can be dispersed up to 70% by weight. At this time, in order to facilitate dispersion and wetting, 48 g of Hexaglyn PR-15, a dispersant, was added to the dispersion medium. In order to maintain a constant concentration was stirred using a paddle mixer to ensure that the zinc oxide is constantly mixed with the dispersion medium. At this time, by installing a baffle in the reactor to cause turbulence, the stirring time can be shortened.

The subsequent process was carried out in the same manner as in Example 1. The oil dispersion of zinc oxide showed a stable dispersion state in Finsolv TN and ININ, which are ester oils, unlike the oil dispersion of titanium dioxide. The average particle size was 150 to 180 nm.

Example 13 Silicone Oil Dispersion of ZnO

240 g of zinc oxide treated with dimethicone was slowly added to 112 g of DC345 and stirred. The surface treated zinc oxide was dispersed up to 70% by weight. At this time, 48 g of EMALEX SS 5050, a dispersant, was added to DC345 to facilitate dispersion and wetting. The subsequent process was carried out in the same manner as in Example 1. As a result of dispersion of zinc oxide, it showed stable dispersion state and the average particle size was 160 ~ 190nm.

As described in the above Examples and Test Examples, the present invention has developed a skin delivery system that can prevent aggregation of titanium dioxide and zinc oxide, which are inorganic sunscreen agents, and a technology for securing stability of the system. Furthermore, it is possible to provide an external composition for skin containing titanium dioxide and zinc oxide, which are stable inorganic sunscreen agents having effective sunscreen ability.

Claims (9)

(A) adding a dispersant to the dispersion medium, followed by stirring to maintain a constant concentration to prepare a lipophilic phase, The dispersant used herein is at least one selected from the group consisting of cetyl PEG (polyethylene glycol), cetyl polypropylene glycol (PPG), polyoxyethylene-methylpolysiloxane copolymer, and polyhexaglycerin resinoleate, The dispersion medium is at least one selected from the group consisting of C12-15 alkylbenzoate, isononylisonananoate, isopropylmyrilate, octyldodecylolate and cyclomethicone; (B) a wet process and a primary dispersion step of adding and stirring an inorganic sunscreen to the lipophilic phase to wet the inorganic sunscreen in the lipophilic phase and simultaneously milling with beads to reduce the particles; (C) separating the inorganic sunscreen oil dispersion prepared by the dispersion in step (b) with the beads; (D) a steady state step of stirring the concentration of the inorganic sunscreen of the oil dispersion separated from the beads to be constant; And (E) separating and stabilizing the aggregated particles by applying high energy using a dynomil or a microfluidizer after the stirring; A method of producing an oil dispersion comprising an inorganic sunscreen. The method of claim 1, wherein the inorganic sunscreen of (b) is at least one selected from the group consisting of titanium dioxide and zinc oxide. The method of claim 2, wherein the inorganic sunscreen is contained in an amount of 0.1 to 70% by weight based on the total weight of the oil dispersion. The method of claim 1, wherein the dispersion medium of the oil dispersion is an ester oil or a silicone oil. The method of claim 1, wherein the dispersant is contained in an amount of 0.1 to 20% by weight. An oil dispersion containing an inorganic sunscreen prepared by the method according to any one of claims 1 to 5. An external preparation composition containing the oil dispersion according to claim 6 in an amount of 0.1 to 60% by weight based on the total weight of the composition. According to claim 7, wherein the external composition is a softening lotion, nourishing cosmetics, massage cream, nutrition cream, pack, gel, lipstick, makeup base, foundation, shampoo, rinse, body cleanser, soap, lotion, ointment, gel, cream, An external preparation composition characterized in that it is formulated as a patch or spray. (A) adding an inorganic sunscreen to the dispersion medium while stirring to prepare a lipophilic phase, The dispersion medium used here is at least one member selected from the group consisting of C12-15 alkylbenzoate, isononylisonanonoate, isopropylmyrilate, octyldodecylolate and cyclomethicone; (B) adding a dispersant to the solution prepared in step (a) and stirring to wet the inorganic sunscreen on the lipophilic phase prepared in step (a) and milling with beads to shrink the particles at the same time. A wetting process and a first dispersion step, The dispersant used herein is at least one selected from the group consisting of cetyl PEG (polyethylene glycol), cetyl polypropylene glycol (PPG), polyoxyethylene-methylpolysiloxane copolymer, and polyhexaglycerin resinoleate; (C) separating the inorganic sunscreen oil dispersion prepared by the dispersion in step (b) with the beads; (D) a steady state step of stirring the concentration of the inorganic sunscreen of the oil dispersion separated from the beads to be constant; And (E) separating and stabilizing the aggregated particles by applying high energy using a dynomil or a microfluidizer after the stirring; A method of producing an oil dispersion comprising an inorganic sunscreen.

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