KR20040061734A - Microfine emulsion containing titanium dioxide and zinc oxide and composition of external application to the skin containing thereof - Google Patents

Abstract

PURPOSE: Provided is an oil dispersant of titanium dioxide and zinc oxide in high concentration, a method for manufacturing the same and a composition of external application containing the same. CONSTITUTION: A method for manufacturing an oil dispersant comprises the steps of: adding dispersant to dispersion medium and stirring them to maintain their concentration constant and give oilphilic phase; adding UV blocking agent to the oilphilic phase and stirring them to the UV blocking agent in the oilphilic phase with milling using beads; separating the oil dispersant from the beads; stirring the separated beads and oil dispersant; and applying high energy after stirring to separate particles and stabilizing them.

Description

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

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 was to prevent sun burns in leisure activities, that is, to prevent excessive sun exposure, and to protect against UV rays in everyday life. It is changing in the direction of suppressing the generation of wrinkles and the like.

The material having the ultraviolet protective function can be classified into organic ultraviolet absorber which absorbs ultraviolet rays and converts energy into heat, wave, fluorescence, radical, etc. and ultraviolet scattering agent which is inorganic pigment which 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 light with wavelengths longer than 405 nm and zinc oxide scatters ultraviolet light with wavelengths longer than 385 nm.

* λ = 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 becoming important with the 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 can be reduced, but can 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, metal soap treatment, or the like.

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. These clumps generally have a particle size much larger than 1um. 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 results in no 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 crystal structure and crystal structure are as follows.

Anatase is a crystal in which the crystal units are connected to the vertices (point contact), Rutile is a crystal shape in which the crystal units are connected to the side edges (line contact), and compared their properties in Table 1 below.

Comparison of Properties According to the Structure of Titanium Dioxide Anatase 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. 'Agglomeration' or 'dusting' due to the production of these particles is generated, thereby adversely affecting the cosmetic containing it, and also reduces the stability of the cosmetic and the stability of the formulation during storage. As described above, 'agglomeration' and 'dusting' according to the growth of inorganic particles for UV protection are critical factors in formulating and blocking UV rays of inorganic particles which are effective sunscreens. Techniques to prevent particle agglomeration, such as 'agglomeration' or 'dusting', are essential for developing an effective inorganic UV second step. Therefore, high dispersion and stability of dispersion state are important keys. In other words, as a surface treatment for enhancing the dispersibility in the dispersion medium, a surface treatment such as aluminum stearate to enhance the dispersibility in the oil phase or a surface treatment using silica or a hydrophilic polymer to increase the dispersibility in the aqueous phase is proposed. Developed.

Although many dispersion systems have been developed, stable dispersion systems have 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, it has been developed that the final dispersion state is a high viscosity gel state using a high melting point ester oil (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 when the temperature rises, 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 generally 70 to 80 ° C., agglomeration may occur due to the influence of the temperature of dispersed titanium dioxide or zinc oxide.

Also, after dispersing titanium dioxide in a dispersion medium, an appropriate dispersant was added, followed by agitation, and then a dispersion process into fine particles using a mill before use (US patent NO. 5,573,753).

In addition, a dispersion system has been invented 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 patent 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.

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 agglomeration of particles of titanium dioxide and zinc oxide, 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.

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

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

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 an oil dispersion of the inorganic sunscreen of the present invention comprises 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.

As the dispersion medium of the present invention, ester oil and silicone oil may be used.

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 peddle 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 abrasion. 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.

Trade name / product INCI name Source Dispersion Finsolv TN C12 ~ 15 Alkyl Benzoate Fintex Inc. ININ Isononyl isononanoate DUBIOS Inc. IPM Iso propyl Myristrate ODO Octyl Dodecyl Oleate DC345 Cyclo Methicone Dow Corning Titanium dioxide M170 Titanium dioxide / aluminium oxide / demethicone Kemira Inc. TTO S-2 Titanium dioxide / aluminium 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, when titanium dioxide is used, Hexaglyn PR-15 is preferred as the dispersion medium and dispersant of ester oil in titanium dioxide M170, and EMALEX SS5050 is preferred as the dispersion medium and dispersant in silicone oil TTO S-2. .

In addition, when using zinc oxide, both ester oil-Hexaglyn PR-15 and silicon 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.

As the surface treatment material, since the dispersion medium is lipophilic, it is composed of a lipophilic coating material suitable for this. Representative organic coating materials include silicone-based coatings such as dimethyldimethoxy silane, dimethicone, methicone and polysiloxane, and fatty acid coatings such as stearic acid, oleic acid, and linoleic acid.Aluminum hydroxide is an inorganic coating material. , Zirconium and the like are possible.

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, etc. 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 poly-hexaglycerin recinolate (trade name: Hexaglyn PR-15, manufactured by Nikko Chemical Co., Ltd., hereinafter referred to as Hexaglyn PR-15) as a dispersion medium, C _12-15 Alkyl Benzoate (trade name: Finsolv TN, manufactured by Fintex Inc., hereinafter referred to as Finsolv TN), and the mixture is stirred for 2 to 3 hours at a speed of 50 to 200 rpm to maintain a constant concentration. 120 g of titanium dioxide (trade name: M170, manufactured by Kemira, hereinafter referred to as 170) is added thereto. To maintain a constant concentration, use a paddle mixer to stir to ensure that M170 is constantly mixed with the dispersion medium. In this case, the stirring time can be shortened by installing a blocking membrane in the reactor to cause turbulence.

The ball mill is used to cause primary size reduction after stirring to allow wetting for sufficient time. The zirconium beads used in the ball mill use a size of about 30 mm. It is appropriate that the input amount of beads is 2 to 3: 1 by volume ratio of oil dispersion and beads.

Then, after separating the beads and the oil dispersion, the dispersion Hexaglyn PR-15 is stirred for 1 hour to uniformly adsorb the M170 and then finely dispersed using a high pressure, continuous vertical mill. At this time, the beads use a size of about 3 ~ 5um. Precipitation of oil dispersion can occur after a long time after the first dispersion, so that the concentration is kept constant by stirring with a stirrer before the second microdispersion, and the dispersant can adsorb the titanium dioxide uniformly. To help.

Example 2 ININ Oil Dispersion of M170

40 g of Hexaglyn PR-15, a dispersant, is added to 240 g of Isononyl isononanoate (trade name: ININ, manufactured by Dubios Inc., hereinafter, ININ), and stirred at a speed of 50 to 200 rpm for 2-3 hours to maintain a constant concentration. Add 120 g of M170 to it. To maintain a constant concentration, use a paddle mixer to stir to ensure that M170 is constantly mixed with the dispersion medium. At this time, it is possible to perform smooth agitation by installing a blocking membrane in the reactor to cause turbulence.

The ball mill is used to cause primary size reduction after stirring to allow wetting for sufficient time. The zirconium beads used in the ball mill use a size of about 30 mm. It is appropriate that the input amount of beads is 2 to 3: 1 by volume ratio of oil dispersion and beads.

After separating the beads and the oil dispersion, the mixture was stirred for 1 hour, and then subjected to microdispersion using a high pressure, continuous vertical mill. At this time, the beads use a size of about 3 ~ 5um. Precipitation of oil dispersion can occur after a long time after the first dispersion, so that the concentration is kept constant by using a paddle stirrer before performing the second microdispersion.

Example 3 IPM Oil Dispersion of M170

40 g of Hexaglyn PR-15, a dispersant, is added to 240 g of Iso propyl mystrate (trade name: IPM, hereinafter referred to as IPM) and stirred at a speed of 50 to 200 rpm for 2-3 hours to keep the concentration constant. Add 120 g of M170 to it. To maintain a constant concentration, use a paddle mixer to stir to ensure that M170 is constantly mixed with the dispersion medium.

The ball mill is used to cause primary size reduction after stirring to allow wetting for sufficient time. The zirconium beads used in the ball mill use a size of about 30 mm. It is appropriate that the input amount of beads is 2 to 3: 1 by volume ratio of oil dispersion and beads.

After separating the beads and the oil dispersion after stirring for 1 hour, the microdispersion is performed using a high pressure, continuous vertical mill. At this time, the beads use a size of about 3 ~ 5um. Precipitation of oil dispersion can occur after a long time after the first dispersion, so the concentration is kept constant by using a paddle stirrer before performing the second undispersion.

Example 4 ODO Oil Dispersion of M170

40 g of Hexaglyn PR-15, a dispersant, is added to 240 g of Octyl dodecyl oleate (trade name: ODO, hereinafter referred to as ODO) as a dispersion medium, and stirred at a speed of 50 to 200 rpm for 2-3 hours to keep the concentration constant. Add 120 g of M170 to it. At this time, it is added to the ODO to facilitate the dispersion and wetting. To maintain a constant concentration, use a paddle mixer to stir to ensure that M170 is constantly mixed with the dispersion medium.

The ball mill is used to cause primary size reduction after stirring to allow wetting for sufficient time. The zirconium beads used in the ball mill use a size of about 30 mm. It is appropriate that the input amount of beads is 2 to 3: 1 by volume ratio of oil dispersion and beads.

After separating the beads and the oil dispersion after stirring for 1 hour, the microdispersion is performed using a high pressure, continuous vertical mill. At this time, the beads use a size of about 3 ~ 5um. Precipitation of oil dispersion can occur after a long time after the first dispersion, so the concentration is kept constant by using a paddle stirrer before performing the second undispersion.

Example 5 ININ Oil Dispersion of M170

120 g of M170 is added to 240 g of Isononyl isononanoate (trade name: ININ, manufactured by Dubios Inc., hereinafter called ININ) with gentle stirring. M170 can be dispersed up to 60% by weight. At this time, 40 g of Hexaglyn PR-15, a dispersant, is added to ININ to facilitate dispersion and wetting. To maintain a constant concentration, use a paddle mixer to stir to ensure that M170 is constantly mixed with the dispersion medium. At this time, it is possible to perform smooth agitation by installing a blocking membrane in the reactor to cause turbulence.

The ball mill is used to cause primary size reduction after stirring to allow wetting for sufficient time. The zirconium beads used in the ball mill use a size of about 30 mm. It is appropriate that the input amount of beads is 2 to 3: 1 by volume ratio of oil dispersion and beads.

After separating the beads and the oil dispersion, the mixture was stirred for 1 hour, and then subjected to microdispersion using a high pressure, continuous vertical mill. At this time, the beads use a size of about 3 ~ 5um. Precipitation of oil dispersion can occur after a long time after the first dispersion, so that the concentration is kept constant by using a paddle stirrer before performing the second microdispersion.

Test Example 1 Comparison of Particle Size Analysis (Examples 1 to 4)

The dispersion state is measured by analyzing the size of particles in which titanium dioxide in each of Examples 1 to 4 is 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. In the case of the ODO dispersion of Example 4, there is no wet and primary dispersion. Therefore, it can be seen that M170 and the dispersant Hexaglyn PR-15PH do not form a proper dispersion system. However, the dispersion process of the remaining 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: ABILEM90, hereinafter ABIL EM90), a typical silicone surfactant, was added to 212 g of cycloclomethicon (trade name: DC345, hereinafter referred to as DC345), a dispersion medium, at a speed of 2 to 50 rpm. Stir for 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) is added thereto. Stir using a paddle mixer to maintain a constant concentration so that TTO S-2 is constantly mixed with the dispersion medium.

The subsequent process is the same as in Example 1.

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

Polyoxyethylene-MethylpolySiloxane copolymer (trade name: EMALEX SS 5050, manufacturer: Nihon Emulsion Co., Ltd., hereinafter referred to as EMALEX SS 5050), a typical silicone surfactant, was added to 2345 g of a dispersion medium, DC345, at a speed of 50 to 200 rpm. Stir for 2-3 hours to keep the concentration constant. Add 140 g of TTO S-2 to it. Stir using a paddle mixer to maintain a constant concentration so that TTO S-2 is constantly mixed with the dispersion medium.

The subsequent process is the same 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, manufactured by Ishihara Sangyo Kaisha Ltd., hereinafter referred to as TTO S-2) is slowly added to 212 g of Cyclo methicon (trade name: DC345, hereinafter referred to as DC345) and stirred. TTO S-2 can be dispersed up to 60% by weight. At this time, a dispersant is added to DC345 to facilitate dispersion and wetting. The dispersant is added 48 g of Cetyl PEG / PPG (trade name: ABIL EM90, hereinafter referred to as ABIL EM90), which is a typical silicone surfactant. Stir using a paddle mixer to maintain a constant concentration so that TTO S-2 is constantly mixed with the dispersion medium.

The subsequent process is the same as in Example 1.

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

Add 140 g of TTO S-2 to 212 g of DC345 and stir. TTO S-2 disperses up to 60% by weight. At this time, a dispersant is added to DC345 to facilitate dispersion and wetting. The dispersant is added 48 g of a polyoxyethylene-MethylpolySiloxane copolymer (trade name: EMALEX SS 5050, manufacturer: Nihon Emulsion Co., Ltd., hereinafter referred to as EMALEX SS 5050), which is a typical silicone surfactant. Stir using a paddle mixer to maintain a constant concentration so that TTO S-2 is constantly mixed with the dispersion medium.

The subsequent process is the same as in Example 1.

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

In Examples 6 and 7, the stearic acid is coated on the surface of titanium dioxide. In order to disperse this in the DC345, a silicone oil, a dispersant having 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, a dispersant, is added to 152 g of ester oil Finsolv TN, which is a dispersion medium, and stirred at a speed of 50 to 200 rpm for 2-3 hours to keep the concentration constant. To this is added 200 g of zinc oxide surface-treated with dimethicone. To maintain a constant concentration, a paddle mixer is used to stir so 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 is the same as in Example 1. Unlike the oil dispersion of titanium dioxide, zinc oxide has a stable dispersion state in Finsolv TN and ININ, which are ester oils. The average particle size is 150 to 180 nm.

Example 11 Silicone Oil Dispersion of ZnO

48 g of EMALEX SS 5050, a dispersant, is added to 112 g of DC345, a dispersion medium, and stirred at a speed of 50-200 rpm for 2-3 hours to keep the concentration constant. To this is added 240 g of zinc oxide surface-treated with dimethicone. The subsequent process is the same 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 is gradually added to 152 g of ester oil, ININ, and stirred. Dimethicone treated zinc oxide can be dispersed up to 70% by weight. At this time, 48 g of Hexaglyn PR-15, a dispersant, is added to the dispersion medium to facilitate dispersion and wetting. To maintain a constant concentration, a paddle mixer is used to stir so 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 is the same as in Example 1. Unlike the oil dispersion of titanium dioxide, zinc oxide has a stable dispersion state in Finsolv TN and ININ, which are ester oils. The average particle size is 150 to 180 nm.

Example 13 Silicone Oil Dispersion of ZnO

240 g of dimethicone-treated zinc oxide is slowly added to 112 g of DC345 and stirred. The surface treated zinc oxide is dispersed up to 70% by weight. At this time, 48 g of EMALEX SS 5050, a dispersant, is added to DC345 to facilitate dispersion and wetting. The subsequent process is the same 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 capable of preventing agglomeration of titanium dioxide and zinc oxide, which are inorganic sunscreen agents, and a technology for securing stability of the system. Furthermore, it can provide the skin external preparation composition of titanium dioxide and zinc oxide which are stable inorganic sunscreens which have an effective ultraviolet-blocking ability.

Claims (9)

(A) adding a dispersant to the dispersion medium, followed by stirring to maintain a constant concentration to form a lipophilic phase; (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 after the stirring; Method for producing a stable oil dispersion containing an inorganic sunscreen, characterized in that it comprises a. The method of claim 1, wherein the inorganic sunscreen according to (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 agent 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 for producing an oil dispersion according to claim 1, wherein the dispersant is contained in an amount of 0.1 to 20% by weight. Stabilized oil dispersion, characterized in that it contains an inorganic sunscreen prepared by the process according to claim 1. An external preparation composition comprising 0.1 to 60% by weight of an oil dispersion of the inorganic sunscreen according to claim 6, 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 cleaning composition, lotion, ointment, External preparation composition, characterized in that the gel, cream, patch or spray formulation. (A) adding an inorganic sunscreen to the dispersion medium while stirring to disperse; (B) Wetting process and primary dispersion in which the dispersant is added to the solution prepared in step (a) and stirred to wet the inorganic sunscreen in the lipophilic phase, and at the same time, milling with beads to shrink the particles. step; (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 after the stirring; Method for producing a stable oil dispersion containing an inorganic sunscreen, characterized in that it comprises a.