JP2020075845A - Hexagonal boron nitride powder - Google Patents

Abstract

To provide a hexagonal boron nitride powder with excellent water repellency compared with conventional ones, and to provide a composition for solid cosmetics that is excellent in the effect of sustaining the condition applied to the skin.SOLUTION: The present invention provides a hexagonal boron nitride powder that contains hexagonal boron nitride particles having methylhydrogen polysiloxane on its surface, characterized in that the E value obtained by the [Method] below is 10 or more, and a composition for solid cosmetics comprising the same. [Method] 20 g of ethanol-water mixture is weighed in a screw tubular bottle of 30 mL capacity, 0.2 g of hexagonal boron nitride powder is added to the ethanol-water mixed solvent, and the resulting mixture is stirred with a mix rotor and allowed to stand for 2 hours. The E value is defined as the weight% value of ethanol in the ethanol-water mixed solvent at the time when the amount of hexagonal boron nitride powder floating in the screw tubular bottle becomes half of the input amount.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a novel hexagonal boron nitride powder. More specifically, the present invention provides a boron nitride powder which, when used as a powder component constituting a solid cosmetic product, can realize excellent makeup hold in the obtained solid cosmetic product.

  A solid cosmetic represented by a powder foundation generally has a role of covering up spots, freckles, wrinkles, and pores by applying it to the entire face, and evenly adjusting the surface of the skin. Therefore, the above-mentioned cosmetics are required to have properties such as "spread (property that can be smoothly applied on the skin surface)" and "mochi (property to keep the condition applied to the skin)".

  Conventionally, most of the powder components constituting the solid cosmetics are natural minerals such as mica, sericite, and talc, but since these have catalytic activity, other components to be blended in cosmetics. Is said to cause deterioration, and the amount of chemically stable boron nitride used has recently increased. The shape of the boron nitride used at this time is usually a thin and flat shape, and since boron nitride has such a shape, it has excellent adhesion to the skin surface, Cosmetics containing boron nitride are said to be excellent in "spreading" and "mochi" (for example, see Patent Document 1).

  In recent years, the development of boron nitride powder, which is even more superior in mochi than conventional boron nitride, has been progressing.As one of the approaches, we focused on the surface properties of boron nitride particles and made the surface of the boron nitride particles highly water repellent. Attempts have been made to further improve "mochi". For example, Patent Document 2 discloses a highly water-repellent boron nitride powder in which functional groups such as OH groups and carbonyl groups on the surface of boron nitride particles have been removed, and cosmetics containing the boron nitride powder are extremely “mochi”. It is said to be excellent. However, in the method of removing a functional group of Patent Document 2, in order to remove the functional group and to remove the removed functional group out of the system, 1000 ° C. in a nitrogen atmosphere depressurized to 0.005 MPa in the examples, 10 It is said that the heat treatment is performed for a time, and there is a problem that the manufacturing process is complicated.

  On the other hand, as a method for imparting water repellency to powder components, surface treatments such as silicone treatment, alkylsilane treatment, fatty acid treatment, and N-acylamino acid treatment are generally performed, and these surface treatments are disclosed in Patent Document 2. It is remarkably simple as compared with the method of removing a functional group. As a surface treatment of boron nitride used for solid cosmetics, a treatment using dimethylpolysiloxane (hereinafter also referred to as dimethicone) described in Patent Document 3 as a surface treatment agent is generally used, and dispersion in solid cosmetics is performed. And the uniformity of the coating film are said to be improved.

  Therefore, the present inventors first focused on the treatment with dimethicone. That is, when the water repellency of the boron nitride surface-treated with dimethicone was investigated, it was found that it could not be said to be necessarily sufficient, and therefore, it is not sufficiently satisfactory for the “mochi” of the cosmetic product using the boron nitride. It became clear that there was not.

JP-A-5-186205 Japanese Patent No. 6313707 JP, 2018-70484, A

  Therefore, an object of the present invention is to provide a hexagonal boron nitride powder having extremely high water repellency as compared with conventional ones.

  As a result of intensive studies to solve the above problems, the present inventors have found that hexagonal boron nitride powder surface-treated with methylhydrogenpolysiloxane (hereinafter, also referred to as methicone) has extremely high water repellency, The invention was completed.

  That is, the present invention is a hexagonal boron nitride powder containing hexagonal boron nitride particles having methylhydrogenpolysiloxane present on the surface thereof, and an E value determined by the following [method] is 10 or more. It is a hexagonal boron nitride powder characterized by the above.

  [Method] After weighing 20 g of an ethanol-water mixed solvent in a screw tube bottle having a volume of 30 mL, 0.2 g of hexagonal boron nitride powder was added, the screw tube bottle was stirred with a mix rotor, and then left standing for 2 hours, The value of the weight% of ethanol in the ethanol-water mixed solvent when the floating amount of the hexagonal boron nitride powder in the screw tube bottle becomes half of the input amount is defined as an E value.

Furthermore, according to the present invention, the hexagonal boron nitride powder having a viscosity (25 ° C.) of the methylhydrogenpolysiloxane of ^{2 to} 400 mm ² / s, the hexagonal boron nitride particles having an average major axis of 2 to 20 μm, Hexagonal boron nitride powder having an average thickness of 0.2 to 1.5 μm and an aspect ratio of 2.5 to 100, and a solid cosmetic comprising 1 to 70% by mass of the hexagonal boron nitride powder. A composition for use is provided.

  Since the hexagonal boron nitride powder of the present invention has methicone on its surface, it has significantly excellent water repellency as compared with the conventional one. Therefore, the solid cosmetic composition containing the hexagonal boron nitride powder is less likely to run off with sweat or water during use as compared with the conventional composition, and as a result, it is excellent in `` mochi '' and has a long-lasting cosmetic effect. it can.

  The reason why the hexagonal boron nitride powder of the present invention is significantly excellent in water repellency is not clear, but the Si-H group contained in methicone has high reactivity with the surface functional group of hexagonal boron nitride, and thus the methicone has a high reactivity. The present inventors believe that is chemically bonded to the surface functional group of hexagonal boron nitride. In addition, it is considered that the Si—H group of methicone and the OH group on the surface of boron nitride and the N atom of boron nitride formed a hydrogen bond. In addition, it is considered that the Si—H group of methicone has a larger polarity than the Si—Me group, and thus is strongly physically adsorbed on the surface of the boron nitride.

It is the figure which showed the relationship between the ethanol concentration in an ethanol-water mixed solvent, and the floating amount of a boron nitride powder.

<Hexagonal boron nitride powder>
The hexagonal boron nitride powder of the present invention contains hexagonal boron nitride particles having methicone present on the surface thereof.

  In the hexagonal boron nitride particles, the average major axis is preferably 2 to 20 μm, more preferably 3 to 15 μm. The average thickness is preferably 0.2 to 1.5 μm, more preferably 0.4 to 1.2 μm. Further, the aspect ratio is preferably 2.5 to 100, more preferably 4 to 80, and further preferably 5 to 50. Hexagonal boron nitride particles having an average major axis, an average thickness and an aspect ratio within the above-mentioned ranges are preferable because when applied to the skin, they have excellent spreadability and moisturizing properties, an appropriate transparency is obtained, and glossiness hardly occurs. The average major axis and the average thickness are measured by electron microscope observation, and the aspect ratio is a value obtained by dividing the average major axis by the average thickness.

  In the hexagonal boron nitride particles, all the modes in which methicone is present on the surface thereof include the modes in which the hexagonal boron nitride particles are covered. Therefore, the aspect in which methicone is present on the surface of hexagonal boron nitride particles is a mode in which methicone is chemically adsorbed by a dehydration reaction and / or a dehydrogenation reaction with a functional group on the surface of hexagonal boron nitride particles, and methicone is physically present. Examples include an aspect in which they are adsorbed and present, an aspect in which methicone is hydrogen-bonded and present, and an aspect in which these aspects are combined.

  Further, if the hexagonal boron nitride powder containing the hexagonal boron nitride particles has a water repellency shown below, methicon, it is necessary to form a coating layer of uniform thickness on the hexagonal boron nitride particles surface. Alternatively, the part where methicone is present and the part where it is not may be in the shape of a sea island. This is because the functional groups present on the surface of the hexagonal boron nitride particles are not evenly present on the surface, and there are some surfaces on which no functional group is present, which may make it difficult to coat uniformly. Because.

  In the boron nitride powder of the present invention, the hexagonal boron nitride particles are preferably contained in an amount of 10% or more, more preferably 30% or more, and more than 50%, in consideration of the good effect of the present invention. More preferably. Therefore, the boron nitride powder of the present invention may contain boron nitride particles other than the hexagonal boron nitride particles as long as the hexagonal boron nitride particles are included in the range. Examples thereof include hexagonal boron nitride particles that have not been surface-treated, and hexagonal boron nitride particles that have been treated with a surface treatment agent other than methicone.

  Further, the hexagonal boron nitride powder of the present invention is a hexagonal boron nitride powder having an E value of 10 or more, which is obtained by the following method. The E value is an index showing the degree of water repellency of the hexagonal boron nitride powder. The higher the water repellency of the hexagonal boron nitride powder, the higher the E value. Is excellent. The E value is preferably 10 or more, more preferably 13 or more, and further preferably 15 or more. On the other hand, a hexagonal boron nitride powder having an excessively high E value may deteriorate the wash-out property after being used as a solid cosmetic composition, and unless a dedicated cleansing agent is used or repeated washing is repeated. May not be washed off. Therefore, the E value is preferably 80 or less, more preferably 60 or less, and further preferably 40 or less.

  The E value is obtained by the following method. That is, after weighing 20 g of an ethanol-water mixed solvent in a screw tube bottle having a volume of 30 mL, 0.2 g of hexagonal boron nitride powder was added, the screw tube bottle was stirred with a mix rotor, and then allowed to stand for 2 hours, The E value is defined as the weight% value of ethanol in the ethanol-water mixed solvent when the floating amount of the hexagonal boron nitride powder in the screw tube bottle is half the above-mentioned input amount.

  The method for determining the floating amount of the hexagonal boron nitride powder in the screw tube bottle is not particularly limited as long as it is an accurate method, for example, the hexagonal boron nitride powder settled at the bottom of the screw tube bottle together with the mixed solvent. Separated and collected with a dropper, and letting the weight of the residue after fully volatilizing the mixed solvent contained in the recovered hexagonal boron nitride powder be the sedimentation amount, and the value obtained by subtracting the sedimentation amount from the above input amount is the floating amount. be able to. Alternatively, after the hexagonal boron nitride powder settled at the bottom of the screw tube bottle is separated and recovered with a dropper together with the mixed solvent, the mixed solvent contained in the hexagonal boron nitride powder remaining in the screw tube bottle is sufficiently volatilized. The weight of the residue may be used as the floating amount.

  At this time, the floating amount when the weight% of ethanol is 0% by weight (that is, only water) is obtained, and then the floating amount when the weight% of ethanol is increased, for example, by 1% by weight, is further increased by 1% by weight. It may be obtained by performing a detailed experiment in which the operation of obtaining the floating amount is repeated. However, since this method may need to acquire too much data, for example, a preliminary experiment is performed at 10% by weight intervals, an E value is estimated, and a detailed experiment is then performed. Is preferred.

  It is desirable to select a screw tube bottle having an appropriate size so that the precipitated hexagonal boron nitride powder can be separated from the suspended matter and recovered. For example, those having an inner diameter of 2 to 4 cm and a height of 4 to 8 cm are preferable, and more specifically, those having an inner diameter of 3 cm and a height of 6 to 7 cm are preferable.

  The mix rotor may be one that can rotate the screw tube bottle and agitate the hexagonal boron nitride powder and the ethanol-water mixed solvent in the screw tube bottle, for example, a roller diameter of 25 to 40 mm, a roller interval of 27 to It is preferably 45 mm, the gap between the rollers is 2 to 10 mm, and the maximum number of rotations of the roller is 50 rpm or more. More specifically, FLMX-T6-5, MR-5 and the like manufactured by As One Co. can be used.

  The stirring conditions when stirring the screw tube bottle with a mix rotor are sufficient if the hexagonal boron nitride powder can be sufficiently dispersed in the ethanol-water mixed solvent, for example, a roller rotation speed of 50 to 100 rpm, a stirring time of 5 10 minutes is preferable.

<Method for producing hexagonal boron nitride powder>
The hexagonal boron nitride powder of the present invention can be produced by surface-treating the hexagonal boron nitride powder with methicone.

  In the hexagonal boron nitride powder of the present invention, the hexagonal boron nitride particles used for its production (hereinafter, also referred to as raw material hexagonal boron nitride powder) are not particularly limited, and known materials can be used without limitation, For example, you may use what was manufactured based on a well-known manufacturing method. Moreover, what is generally marketed as a solid cosmetic composition may be used, and as such a thing, for example, Mizushima Gokin Iron & Co. make: SHP-3, SHP-6, Saint-Gobain make: PUHP. 3008J, PUHP 1109J and the like.

  In the hexagonal boron nitride powder of the present invention, the methicone used for its production is not particularly limited, and known substances can be used without limitation. The methicone may be used alone or in combination of two or more.

Further, in the hexagonal boron nitride powder of the present invention, the methicone used for its production has a viscosity of ² to 400 mm ² / s, preferably 5 to 100 mm ² / s, and more preferably 10 to 80 mm ² / s. s. By controlling the kinematic viscosity of methicone in the above range, hexagonal boron nitride particles can be obtained with less aggregation of hexagonal boron nitride particles and a good feel. In addition, as the above-mentioned methicone, an ordinary commercially available product can be used. For example, Toray Dow Corning Co., Ltd .: AM-3100 Hydrogen Fluid (40 mm ² / s), Shin-Etsu Chemical Co., Ltd .: KF-99P (20 mm) ^{2 / s), KF-9901} (20mm 2 / s) and the like can be used.

  In the hexagonal boron nitride powder of the present invention, the amount of methicone used for its production is not particularly limited, but is preferably 0.2 to 20 parts by mass with respect to 100 parts by mass of the hexagonal boron nitride powder, and 0.1. 5 to 10 parts by mass is more preferable, and 1 to 5 parts by mass is further preferable. By surface-treating the hexagonal boron nitride powder with the addition amount of methicone in the above range, a hexagonal boron nitride powder excellent in water repellency, spreadability, stickiness and feel can be obtained.

  In the hexagonal boron nitride powder of the present invention, the method of treating the surface of the boron nitride particles with methicone may be any known method without any limitation, for example, in air or in the presence of an inert gas, hexagonal nitriding. Examples thereof include a method in which methicone is spray-added to boron powder or added in a liquid state, and these are mixed. Examples of the mixing device include a V blender that mixes by rotating or rocking the container body, a rocking mixer or a double cone type mixing device, or an air blender that mixes air by air.

  Further, in the above-described method of treating the surface of hexagonal boron nitride particles with methicone, methicone may be diluted with an organic solvent such as alcohols, specifically with ethanol or isopropanol. However, when there is a possibility that the solvent may have an adverse effect on the water repellency of the hexagonal boron nitride powder obtained, after the above treatment, by heating the hexagonal boron nitride powder at a temperature equal to or higher than the boiling point of the solvent, the solvent is sufficiently added. Need to be volatilized.

  In the hexagonal boron nitride powder of the present invention, the temperature for treating the surface of the boron nitride particles with methicone is not particularly limited and may be, for example, a temperature of about 25 ° C, but a method involving heating is preferable, and a temperature of 100 to 300 ° C is more preferable. The temperature is preferably 110 to 200 ° C, more preferably 120 to 180 ° C. Regarding the timing of heating, the heating may be carried out from the beginning together with the mixing, or may be carried out at a temperature of about 25 ° C. for a while after the mixing and then continuously heated. By treating at such a temperature, a hexagonal boron nitride powder having a higher E value than that treated only at a temperature of about 25 ° C. can be obtained. The reason why the heat treatment increases the E value is that the reaction between the surface functional groups of the hexagonal boron nitride and methicone progresses more and more, and the surface of the hexagonal boron nitride particles is more densely covered by the crosslinking reaction of methicone. Things can be considered. As the heating device, a ventilation dryer, a convection dryer, a vacuum dryer, a conical dryer, a drum dryer, a V-shaped dryer, a vibration dryer, a rocking mixer, a Nauta mixer, a ribocon, a vacuum granulation device, a vacuum emulsification device, Other examples include a stirring type vacuum drying device. The treatment time is usually 5 minutes to 1 hour, though it depends on the treatment temperature.

<Solid cosmetic composition>
Since the hexagonal boron nitride powder of the present invention has excellent water repellency as a powder component constituting a solid cosmetic product, a solid cosmetic composition containing the hexagonal boron nitride powder should be treated with sweat or water during use. It does not run off easily, so it has an excellent "mochi" and can maintain the makeup effect for a long time. Therefore, the solid cosmetic composition can be used in various applications as described below. That is, it can be suitably used not only for makeup cosmetics such as foundations, lipsticks, eye shadows and mascaras, but also for facial cosmetics such as emulsions and creams. Among them, the foundation applied to a wide area of the face makes a great contribution to the makeup deterioration of the entire makeup, and therefore it is preferable to use the solid cosmetic composition of the present invention.

  The solid cosmetic composition of the present invention preferably contains the hexagonal boron nitride powder in an amount of 1 to 70% by mass. The solid cosmetic composition containing the hexagonal boron nitride powder in the above range has excellent spreadability and stickiness. A solid cosmetic composition containing more preferably 3 to 40% by mass, and even more preferably 5 to 20% by mass of hexagonal boron nitride powder is preferred.

  In addition, in the solid cosmetic composition of the present invention, the basic components of cosmetics are not particularly limited, and known ones can be used. For example, inorganic powder such as talc, mica, mica, sericite, silicic acid anhydride, silica, aluminum oxide, titanium oxide, zinc oxide, iron oxide, zirconium oxide; nylon 12, (vinyl dimethicone / methicone silsesquioxane) Crosspolymers, (diphenyldimethicone / vinyldiphenyldimethicone / silsesquioxane) crosspolymers, acrylates crosspolymers, polymers such as polymethylmethacrylate polymers; silane compounds such as perfluorooctyltriethoxysilane; ethylhexyl methoxycinnamate, etc. UV absorbers; pigments such as silicone-treated red iron oxide (red iron oxide), silicone-treated yellow iron oxide, silicone-treated black iron oxide, silicone-treated titanium oxide; higher aliphatic alcohols, higher fatty acids, ester oils, paraffin oils, waxes, etc. Oils; alcohols such as ethyl alcohol, propylene glycol, sorbitol, glucose; moisturizers such as mucopolysaccharides, collagens, lactates; various surfactants, thickeners, antioxidants, pH buffers, preservatives, Raw materials such as fragrances usually used in cosmetics are appropriately selected and blended.

  It is preferable that the inorganic powder is water-repellent by surface treatment. By imparting water repellency to inorganic powders other than the hexagonal boron nitride powder, it is possible to obtain a solid cosmetic composition having more excellent “mochi”.

  Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

  Various evaluation results are measured by the following methods (1) to (8). The hexagonal boron nitride powder used in the present invention is shown in (9).

(1) E value of hexagonal boron nitride powder 20 g of each ethanol-water mixed solvent prepared to have an ethanol concentration of 0, 10, 20, 30 and 40% by weight was used as a Labone screw bottle No. 6 (capacity 30 mL) individually, and further, 0.2 g of hexagonal boron nitride powder was put into each screw tube bottle, and the screw tube bottle was rotated at 70 rpm using a mix rotor FLMX-T6-5 manufactured by AS ONE Corporation. Stirred for 10 minutes. After allowing it to stand for 2 hours, the hexagonal boron nitride powder settled at the bottom of the screw tube bottle was separated and collected with a dropper together with a mixed solvent, and the mixed solvent contained in the separated and collected hexagonal boron nitride was sufficiently volatilized. The weight of the subsequent residue was defined as the sedimentation amount (g), and the value obtained by subtracting the sedimentation amount (g) from the input amount (g) was defined as the floating amount (g).

  Next, a preliminary experiment was performed in which the weight% of ethanol was changed at intervals of 10% by weight, the relationship between the weight% of ethanol and the floating amount shown in FIG. 1 was calculated, and the E value was estimated. Meanwhile, the E value was obtained.

(2) Average major axis, average thickness, and aspect ratio of hexagonal boron nitride particles 100 parts by mass of hexagonal boron nitride powder are dispersed in 100 parts by mass of epoxy resin, and the obtained resin composition is defoamed under reduced pressure to obtain a tester industry. Using a company-made automatic coating machine PI-1210, the resin composition is coated on a PET film to a thickness of about 250 to 400 μm, dried and cured, and further vacuum-pressed at 100 to 150 ° C. and 75 kN to give a thickness of 100. A sheet of ˜200 μm was prepared.

  Next, the obtained sheet was cut out in a length of 5 mm × width of 5 mm, and one of the surfaces perpendicular to the thickness direction of the sheet was subjected to cross-section milling at the center, and the processed surface was subjected to SEM under a condition of a magnification of 2500. The image was taken by. 100 hexagonal boron nitride particles were randomly selected from the obtained image, the long side (= long diameter) and the short side (= thickness) of the particles were measured, and each average value was calculated as the average long diameter (μm). A value obtained by dividing the average major axis by the average thickness was defined as the aspect ratio (average major axis / average thickness).

(3) Average particle size (D ₅₀ ) of hexagonal boron nitride powder
Hexagonal boron nitride powder 0.3 g was put into a screw tube bottle having a volume of 100 cc and a diameter of 4 cm together with 50 cc of ethanol, and a probe having a diameter of 0.2 cm was inserted in water for 1 cm. The particle size distribution was measured using a laser diffraction / scattering type particle size distribution measuring device (LA-950V2 manufactured by HORIBA) for the boron nitride suspension after applying ultrasonic waves for 5 minutes at an output of 50 W, and the average particle size was measured. (D ₅₀ ) (μm) was determined.

(4) DBP absorption of hexagonal boron nitride powder The DBP absorption of hexagonal boron nitride powder was measured by the method according to JIS-K-6217-4.

  That is, the horizontal axis: DBP dropping amount (ml) measured according to JIS-K-6217-4, the vertical axis: maximum torque (Nm) calculated from the torque (Nm) curve, DBP absorption amount (ml / 100 g). I asked. The measuring device was S-500 manufactured by Asahi Soken Co., Ltd. The measurement conditions were the DBP absorption rate using a DBP dropping rate of 4 ml / min, a stirring blade rotation number of 125 rpm, a sample input amount of 30 g, and a dropping amount of 70% of the maximum torque. DBP (Dibuty Phthalate) was performed using Wako Pure Chemical Industries, Ltd. limited express reagent (sales agency code 021-06936).

(5) Lightly loaded bulk density and tapped bulk density of hexagonal boron nitride powder The lightly loaded bulk density (g / cm ³ ) and tapped bulk density (g / cm ³ ) were measured using a Seishin Enterprise: Tap Denser KYT-5000. .. The sample cell was 100 ml, the tap speed was 120 times / min, the tap height was 5 cm, and the number of taps was 500 times.

(6) Specific Surface Area of Hexagonal Boron Nitride Powder The specific surface area (m ² / g) was measured by using Macsorb HM model-1201 manufactured by Mountech Co., Ltd.

(7) Elution Boron Amount of Hexagonal Boron Nitride Powder Eluted boron was extracted by a method according to the Quasi-drug Raw Material Standard 2006, and the amount of boron (ppm) was measured by an ICP emission spectroscopy analyzer.

  That is, 2.5 g of hexagonal boron nitride powder was placed in a Teflon (registered trademark) beaker, 10 mL of ethanol was added and well stirred, and 40 mL of water was further added and well stirred, and then a Teflon (registered trademark) watch glass was put on the beaker, It was heated at 50 ° C. for 1 hour. After cooling, the mixture was filtered, the residue was washed with a small amount of water, and the washings were combined with the filtrate. This liquid was further filtered with a membrane filter (0.22 μm). The entire amount of the filtrate was placed in a Teflon (registered trademark) beaker, 1 mL of sulfuric acid was added, and the mixture was boiled on a hot plate for 10 minutes. After cooling, this solution was placed in a polyethylene measuring flask, the Teflon (registered trademark) beaker was washed with a small amount of water, and after being combined with the polyethylene measuring flask, water was added to make exactly 50 mL, and this was used as a sample solution. The amount of boron in the sample solution was measured with an ICP emission spectroscopy analyzer.

(8) Nobi and Mochi of the composition for solid cosmetics Table 1 shows the results of sensory evaluation of "Nobi" and "Mochi" by 20 specialized panelists. The results are as follows: if the panelists who feel good are less than 30%, it is ×, if it is 30% or more and less than 60%, it is △, if it is 60% or more and less than 80%, it is ○, and if it is 80% or more, it is ◎. And

(9) Raw material hexagonal boron nitride powder A raw material hexagonal boron nitride powder was produced by the following method.

  1150 g of boron oxide, 490 g of carbon black and 160 g of calcium carbonate were mixed in a ball mill. The mixture was heated to 1500 ° C. at a rate of 15 ° C./minute and kept at 1500 ° C. for 6 hours using a graphitized Tammann furnace in a nitrogen gas atmosphere. After the temperature was maintained at 1500 ° C., the temperature was raised to 1800 ° C. at 15 ° C./minute, the temperature was maintained at 1800 ° C. for 2 hours, and reduction nitriding treatment was performed.

  Next, the obtained crude hexagonal boron nitride powder was put into a polyethylene container, 10 times as much hydrochloric acid aqueous solution (10 wt% HCl) as that of the crude hexagonal boron nitride was added, and the mixture was stirred at 300 rpm for 15 hours. After the acid washing, the acid is filtered, washed again with pure water having a resistivity of 1 MΩ · cm at 25 ° C., which is 300 times the amount of the crude hexagonal boron nitride, and then filtered by suction. Dehydration was performed until the water content in the powder was 50 wt% or less.

  After washing with pure water, the obtained powder was dried under reduced pressure at 200 ° C. for 15 hours under a pressure of 1 kPaA to obtain a white hexagonal boron nitride powder. Further, the dried powder was passed through a sieve having openings of 90 μm to remove coarse particles to obtain a raw material hexagonal boron nitride powder used in Examples and Comparative Examples.

With respect to the obtained raw material hexagonal boron nitride powder, when the above (2) to (7) were measured, E value was 0%, average major axis 6 μm, average thickness 0.9 μm, aspect ratio 7, average particle size (D ₅₀ ) 7 μm, DBP absorption amount 97 ml / 100 g, lightly loaded bulk density 0.09 g / cm ³ , tap bulk density 0.29 g / cm ³ , specific surface area 2 m ² / g, and amount of eluted boron 1 ppm.

[Example 1]
15 g of the raw material hexagonal boron nitride powder was placed in a container, 0.3 g of methyl hydrogen polysiloxane (KF-9901 manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise with stirring with a spoon, and the entire amount was transferred to a PFA round bottom flask (capacity 250 mL). After that, a hexagonal boron nitride powder containing hexagonal boron nitride particles having methylhydrogenpolysiloxane present on the surface was obtained by stirring at 300 rpm for 30 minutes using a three-one motor and a Teflon (registered trademark) stirring blade. Obtained. Table 1 shows the results of measuring the E value of the obtained hexagonal boron nitride powder.

[Example 2]
Hexagonal nitriding containing hexagonal boron nitride particles having methylhydrogenpolysiloxane present on the surface in the same manner as in Example 1 except that KF-99P manufactured by Shin-Etsu Chemical Co., Ltd. was used as the methylhydrogenpolysiloxane. A boron powder was obtained. Table 1 shows the results of measuring the E value of the obtained hexagonal boron nitride powder.

[Example 3]
Hexagonal boron nitride particles having methylhydrogenpolysiloxane on the surface were prepared in the same manner as in Example 1 except that AM-3100 Hydrogen Fluid manufactured by Toray Dow Corning Co., Ltd. was used as the methylhydrogenpolysiloxane. A hexagonal boron nitride powder containing was obtained. Table 1 shows the results of measuring the E value of the obtained hexagonal boron nitride powder.

[Examples 4 and 5]
The hexagonal boron nitride powders obtained in Examples 1 and 2 are heated in an electric furnace at 150 ° C. for 30 minutes to give hexagonal boron nitride particles having methylhydrogenpolysiloxane on the surface. A crystalline boron nitride powder was obtained. Table 1 shows the results of measuring the E value of the obtained hexagonal boron nitride powder.

[Comparative Example 1]
Table 1 shows the results of measuring the E value of the raw material hexagonal boron nitride powder.

[Comparative example 2]
A hexagonal boron nitride powder containing hexagonal boron nitride particles having dimethylpolysiloxane on the surface was obtained in the same manner as in Example 1 except that KF-96L manufactured by Shin-Etsu Chemical Co., Ltd. was used as the dimethylpolysiloxane. It was Table 1 shows the results of measuring the E value of the obtained hexagonal boron nitride powder.

[Comparative Examples 3 and 4]
The hexagonal boron nitride powders obtained in Comparative Examples 1 and 2 were heated in an electric furnace at 150 ° C. for 30 minutes to give hexagonal boron nitride particles containing hexagonal boron nitride particles having dimethylpolysiloxane on the surface. A boron powder was obtained. Table 1 shows the results of measuring the E value of the obtained hexagonal boron nitride powder.

[Examples 5-9, Comparative Examples 5-8]
The hexagonal boron nitride powders obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were used to prepare solid cosmetic compositions containing the hexagonal boron nitride powder in the following blending ratios.

Hexagonal boron nitride powder 20.0% by mass
Mica 15.0 mass%
Synthetic phlogopite 12.0 mass%
Ethylhexyl methoxycinnamate 8.0% by mass
(Vinyl dimethicone / methicone silsesquioxane) crosspolymer 8.0 mass%
(Diphenyldimethicone / Vinyldiphenyldimethicone /
Silsesquioxane) crosspolymer 8.0 mass%
Nylon 12 3.0% by mass
Silica 3.0 mass%
Talc 3.0 mass%
Acrylate Cross Polymer 3.0% by mass
Perfluorooctyltriethoxysilane 3.0 mass%
Zinc oxide 3.0 mass%
Polymethylmethacrylate polymer 3.0 mass%
Silicone-treated red iron oxide (red iron oxide) 1.0% by mass
Silicone treated yellow iron oxide 0.6% by mass
Silicone treated black iron oxide 0.4% by mass
Silicone treated titanium oxide 6.0% by mass

Claims (4)

A hexagonal boron nitride powder containing hexagonal boron nitride particles having methylhydrogenpolysiloxane present on its surface,
E value determined by the following [method] is 10 or more, hexagonal boron nitride powder.
[Method] After weighing 20 g of an ethanol-water mixed solvent in a screw tube bottle having a volume of 30 mL, 0.2 g of hexagonal boron nitride powder was added, the screw tube bottle was stirred with a mix rotor, and then left standing for 2 hours, The value of the weight% of ethanol in the ethanol-water mixed solvent when the floating amount of the hexagonal boron nitride powder in the screw tube bottle becomes half of the input amount is defined as an E value. The hexagonal boron nitride powder according to claim 1, wherein the methylhydrogenpolysiloxane has a viscosity (25 ° C) of ^{2 to} 400 mm ² / s.   The hexagonal boron nitride powder according to claim 1 or 2, wherein the hexagonal boron nitride particles have an average major axis of 2 to 20 µm, an average thickness of 0.2 to 1.5 µm, and an aspect ratio of 2.5 to 100.   A solid cosmetic composition comprising the hexagonal boron nitride powder according to claim 1 in an amount of 1 to 70% by mass.

Images