Surface-treated amorphous spherical silica and use thereof

Abstract

To provide surface-treated silica to which low hygroscopicity, high compatibility with a solvent, easy dispersibility in a resin and a low aggregation amount are imparted.SOLUTION: The surface-treated amorphous spherical silica satisfies all of the following physical properties: (1) a pore volume amount measured by a nitrogen adsorption method is 0.05 mL / g or less (2) a cumulative 50% volume diameter measured by a laser diffraction method is 1 to 20 μm (3) an amount of particles having a particle size of more than 45 μm measured by a wet sieving method is 2 mass% or less (4) a value of n obtained when a particle size measured by a laser diffraction method is plotted on a Rosin-Rammler diagram is 1.5 to 3.0 (5) a carbon content is 0.01% or more and 5.00% or less (6) a degree of crystallinity is less than 0.10% (7) a circularity is 0.80 or more SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to surface-treated amorphous spherical silica, and to a resin composition, a sealant, an adhesive, a film, a cosmetic, and a paint each using the same. [Background technology]

[0002] Silica is used in a variety of applications, for example, resin compositions filled with silica are added to semiconductor encapsulants, adhesives, etc. to improve the reliability of the resin composition. Other applications are diverse, including adding silica to cosmetics to impart a texture, and adding silica to films to impart anti-blocking effects and hard coating properties. In antiblocking agents added to films and cosmetic compositions such as foundations, spherical particles with a particle size of about 1 to 20 μm are used for the purposes of exerting an antiblocking effect, improving the feel of use of the cosmetic, enhancing the covering effect, etc. Typical spherical particles for the above purposes are resin beads such as acrylic powder and nylon powder, and silica.

[0003] Although resin beads have excellent properties in improving the feel of use, there are concerns that their accumulation in the ocean may have an impact on ecosystems, and regulations regarding their addition to cosmetic compositions are becoming stricter every year. Silica is the main component of sand and is unlikely to have an impact on ecosystems, but as an additive for cosmetics, it has a dry and rough feel and its texture is inferior to that of resin beads. Therefore, there is a demand for silica that has a texture equivalent to that of resin beads.

[0004] Patent Document 1 shows that the feel of cosmetics containing silica produced under specific conditions is improved compared to those containing conventional silica, but there is still room for improvement. Patent Document 2 proposes a powder cosmetic containing porous silica pre-impregnated with an oil agent, which provides a good feel when used, but this method has the disadvantage of limiting the types of cosmetics that can be used. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2011-256098 [Patent Document 2] Patent Publication No. 2016-029028 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the silica surface is hydrophilic, it adsorbs moisture from the air, causing the resin compound to thicken, and there are problems such as poor compatibility with solvents and aggregation, which can lead to a deterioration in the feel of the cosmetic. Therefore, an object of the present invention is to provide a surface-treated silica that has low moisture absorption, high compatibility with solvents, and a low amount of aggregation. [Means for solving the problem]

[0007] As a result of extensive research to achieve the above object, the inventors have found that the above problems can be solved by surface-treating spherical silica having a small pore volume and a specific particle size distribution. That is, the present invention provides a surface-treated amorphous spherical silica that satisfies all of the following physical properties: (1) The pore volume measured by nitrogen adsorption is 0.05 mL / g or less; (2) A cumulative 50% volume diameter measured by laser diffraction is 1 to 20 μm; (3) The amount of particles with a particle size exceeding 45 μm as measured by the wet sieve method is 2% by mass or less; (4) The value of n obtained when the particle size measured by the laser diffraction method is plotted on a rosin Ramler diagram is 1.5 to 3.0; (5) Carbon content is 0.01% or more and 5.00% or less; (6) crystallinity less than 0.1%; (7) Circularity of 0.80 or more;

[0008] The surface-treated amorphous spherical silica preferably has a refined linseed oil absorption of 30 mL / 100 g or less, as measured by the test method described in JIS K5101-13-1. Furthermore, there are provided resin compositions, sealing materials, adhesives, films, cosmetics and paints which contain the surface-treated amorphous spherical silica. [Effects of the Invention]

[0009] The resin compositions, sealants, adhesives, films, and coating materials made from the surface-treated amorphous spherical silica of the present invention exhibit high compatibility and good dispersibility with the respective resins or solvents, and can improve the feel to the touch when added to cosmetics. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following embodiments are examples of the present invention, and the present invention is not limited to these embodiments. Furthermore, unless otherwise specified, the expression "A to B" for a numerical range means "A or more and B or less." In such expressions, when a unit is assigned only to the numerical value B, the unit also applies to the numerical value A.

[0011] <Surface-treated amorphous spherical silica of the present invention> The surface-treated amorphous spherical silica of the present invention is obtained by subjecting amorphous spherical silica, which has been produced by a dry method such as a combustion method, a melting method, or a deflagration method, or a wet method such as a sol-gel method, a gel method, or a precipitation method, to a surface treatment using a known method. Since amorphous spherical silica produced by a wet method contains a solvent in its pores and interior, it can be heat-treated as necessary to burn out the pores, remove the internal solvent, and reduce internal silanol groups, thereby achieving physical properties equivalent to those of amorphous spherical silica produced by a dry method. The surface-treated amorphous spherical silica of the present invention is characterized by being amorphous. Crystalline silica is carcinogenic, and its use as an additive for various applications is undesirable due to the risk of increased health risks. The surface-treated amorphous spherical silica of the present invention is said to be amorphous when the presence of crystalline silica cannot be confirmed by X-ray diffraction. Note that when a similar measurement is performed with 0.1% crystalline silica added, a peak can be observed, indicating that the crystalline silica component is less than 0.1%.

[0012] (Circularity) The present invention relates to surface-treated amorphous spherical silica. The spherical silica used in the present invention has a Wadell practical circularity (circle-equivalent diameter / maximum diameter) of 0.80 or more, preferably 0.85 or more, and more preferably 0.90 or more. The circle-equivalent diameter is defined as the diameter of a circle having an area equal to the projected cross-sectional area of ​​the particle, and the maximum diameter is defined as the maximum distance between any two points on the projected periphery of the particle. Being spherical results in improved filling rate in resin compositions and improved feel when used as a cosmetic additive.

[0013] (pore volume) The surface-treated amorphous spherical silica of the present invention has a pore volume of 0.05 mL / g or less, preferably 0.03 mL / g or less, and more preferably 0.02 mL / g or less, as measured by nitrogen adsorption. If the pore volume exceeds this range, the silica will tend to thicken when mixed with a resin, and when used in cosmetics and comes into contact with the skin, it will absorb sebum and moisture, causing a dry feeling and resulting in a poor feel to the touch. There is no lower limit, but it is generally difficult to obtain silica with a pore volume of 0.005 mL / g or less. The pore volume was determined by drying a sample to be measured at 200°C for 3 hours or longer under a vacuum of 1 kPa or less, obtaining an adsorption isotherm only for the nitrogen adsorption side at liquid nitrogen temperature, and analyzing the isotherm by the BJH method (Barrett, EP; Joyner, LG; Halenda, PP, J. Am. Chem. Soc. 73, 373 (1951)). The pores measured by this method are pores with a radius of 1 to 100 nm, and the integrated value of the volume of pores in this range is the pore volume in the present invention.

[0014] (Cumulative 50% volume diameter) The surface-treated amorphous spherical silica of the present invention has a cumulative 50% volume diameter (also referred to as D50) measured by laser diffraction of 1 to 20 μm, preferably 2 to 15 μm, and more preferably 2 to 10 μm. If D50 is less than 1 μm, the filling rate into resin decreases, the slipperiness as a cosmetic material decreases, and it becomes difficult to disperse aggregated particles, resulting in a rough feeling. On the other hand, if D50 is large, it becomes difficult to seal narrow gaps in recent sealants and the cosmetic material tends to have a rough feeling. If D50 exceeds the above-mentioned 20 μm, it becomes difficult to use. The cumulative 50% volume diameter was calculated using a Microtrac laser diffraction / scattering particle size distribution analyzer (MT-3300EX2) by measuring the dispersion medium. Here, 250 mL of dispersion medium (ethanol) and 0.02 g to 0.1 g of sample were placed in the sample slurry circulation tank of the measurement device, and the sample slurry was ultrasonically dispersed at 40 W for 1 minute while circulating, and the cumulative 50% volume diameter was measured. The amount of sample added was adjusted according to the standard usage method of the device so that the sample slurry concentration value (sample loading value) displayed on the device control computer screen was between 0.85 and 0.90.

[0015] (Amount of particles with a diameter of more than 45 μm) The surface-treated amorphous spherical silica used in the present invention has a particle content of 2% by mass or less, preferably 1% by mass or less, and more preferably 0.5% by mass or less, of particles having a particle size exceeding 45 μm as measured by the wet sieving method. If the content of particles having a particle size exceeding 45 μm as measured by the wet sieving method exceeds this range, it becomes difficult to seal narrow gaps when used as a sealant, and the cosmetic composition may feel rough.

[0016] (The value of n obtained from the Rosin-Rammler diagram) The surface-treated amorphous spherical silica of the present invention has a value of n of 1.5 to 3.0, which is determined by plotting the particle size measured by laser diffraction on a rosin-Rammler diagram. If the value of n exceeds 3.0, the fluidity and feel deteriorate, resulting in a dry feeling. The n value obtained when plotting on the Rosin Ramler diagram was determined by measuring the dispersion medium using a Microtrac laser diffraction / scattering particle size distribution analyzer (MT-3300EX2) and using the Rosin Ramler n value calculation program built into the instrument. The sample preparation and measurement conditions were the same as when measuring the cumulative 50% volume diameter.

[0017] (carbon content) The surface-treated amorphous spherical silica of the present invention has a carbon content of 0.01% to 5.00% or less, preferably 0.02 to 4.50%, and more preferably 0.03 to 4.00%. If the carbon content is less than 0.01%, it is difficult to obtain the effects of the surface treatment, such as improving the filling rate of the sealing material, improving fluidity, and improving the feel of the cosmetic material. If the carbon content exceeds 5.00%, it is likely that a large amount of physically adsorbed surface treatment agent is contained, which may contribute to thickening of the sealing material and deterioration of its effectiveness, which is undesirable. The carbon content can be measured using a general carbon analyzer.

[0018] (true density) The true density of the surface-treated amorphous spherical silica of the present invention is preferably 2.1 or more, and more preferably 2.15 or more. If the true density is less than 2.1, the silica contains a large amount of hollow silica or silica having micropores, which may result in high viscosity and a low filler loading rate when used as a resin composition. Furthermore, when used as a cosmetic, the silica absorbs sebum and moisture upon contact with the skin, causing a dry feeling and resulting in a poor feel to the touch. The true density can be measured using a common hydrometer.

[0019] (specific surface area) The specific surface area of ​​the surface-treated amorphous spherical silica in the present invention is 0.5 to 5.0 m 2 / g, preferably 0.8 to 4.0 m 2 / g, more preferably 1.0 to 3.0 m 2 / g. 0.5m 2 If the molecular weight is less than 5.0 m / g, the resin composition will contain relatively large particles, making it difficult to seal narrow gaps, and the cosmetic composition will tend to have an increased rough feeling when used. 2 If the specific surface area exceeds 1 / g, there is a concern that the viscosity will increase and the filler loading rate will decrease when used as a resin composition. Also, when used as a cosmetic, the feeling of dryness tends to increase. Methods for measuring the specific surface area include the BET single-point method using the nitrogen adsorption method.

[0020] (impurities) The surface-treated amorphous spherical silica of the present invention preferably contains impurities such as heavy metals (e.g., iron, chromium) at a total concentration of 20 ppm or less, and ionic compounds (e.g., NaCl, NaSO) at a concentration of 5 ppm or less. High heavy metal concentrations can cause coloring, while high ionic compound concentrations can affect viscosity.

[0021] <Method for producing surface-treated amorphous spherical silica> Next, a method for producing the surface-treated amorphous spherical silica of the present invention having the above-mentioned characteristics will be described. The surface-treated amorphous spherical silica of the present invention can be produced by surface-treating amorphous spherical silica by a known method. As the amorphous spherical silica, for example, the amorphous spherical fused silica described in JP-A-2020-111526 can be suitably used.

[0022] (Surface treatment method) Known techniques can be used for the surface treatment. Examples include a dry method in which a surface treatment agent is sprayed in liquid or gaseous form and heat-treated, and a wet method in which silica is slurried to prepare a dispersion, and then the surface treatment agent is added and mixed. Of these, the dry method is preferred in order to suppress aggregation and maintain the spherical shape. The method of adding the treatment agent is not particularly limited. If the surface treatment agent is a low-viscosity liquid at room temperature and normal pressure, it can be added dropwise or sprayed in the dry method, or added dropwise into a dispersion in the wet method. If the surface treatment agent is a high-viscosity liquid or solid, it can be added to an appropriate organic solvent to form a solution or dispersion, and then added in the same manner as a low-viscosity liquid. Examples of organic solvents that can be used here include alcohols such as methanol, ethanol, isopropyl alcohol, and butanol; ethers such as tetrahydrofuran and dioxane; and amide compounds such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Furthermore, if the surface treatment agent is gaseous, it can be added by solid-gas contact and reaction in the dry method, or by blowing it into the liquid in the form of fine bubbles in the wet method.

[0023] The mixing means used in the surface treatment is not particularly limited, but in the case of a dry method, it is preferable to use a mixing means that does not rely on a rotor with a drive unit. Specific examples include mixing by rotating or shaking the container body, and airflow mixing using air. Examples of mixing devices that have such mixing means include a V-blender, a rocking mixer, or a double-cone type mixer that mixes by rotating or shaking the container body, or an air blender that mixes by airflow using air. On the other hand, when the mixing means is a rotor with a drive unit, the silica receives a large amount of agitation energy when it collides with the mixing blades, usually at least 50 J, which makes it easy for agglomerated particles to form. Specific examples of such equipment include mixing equipment equipped with agitating blades, mixing blades, etc., such as a Henschel mixer or a Loedige mixer. In the case of the wet method, mixing using a stirring blade, which is a common mixing method, can be used. The shape and size of the blade can be selected taking into consideration the mixing efficiency, and examples include paddle-type, anchor-type, and max blend blades.

[0024] The treatment temperature when performing the surface treatment may be determined taking into consideration the reactivity of the surface treatment agent used, etc. However, if the treatment temperature is too low, the reaction will proceed slowly, and if it is too high, the operation will be complicated. Therefore, in the case of a dry method, the treatment temperature is preferably 50 to 300°C, and more preferably 80 to 200°C, and in the case of a wet method, the treatment temperature is preferably 10 to 100°C, and more preferably 20 to 80°C. The treatment time for the surface treatment is not particularly limited and may be determined taking into consideration the reactivity of the surface treatment agent used, etc. Taking into consideration both the sufficient progress of the surface treatment reaction and shortening the process time, the treatment time is preferably set to 0.1 to 48 hours, and more preferably 0.5 to 24 hours.

[0025] (surface treatment agent) Examples of the surface treatment agent include amino acids, silicone oil, silane coupling agents, silazanes, and fatty acids. The following surface treatment agents may be used alone or in combination of two or more. [Amino acids] As the amino acid, any known amino acid that is commonly used for surface treatment can be used without any particular limitation, and may be appropriately selected and used depending on the required performance of the surface-treated silica particles, etc. Specific examples of amino acids include aspartic acid, glutamic acid, alanine, glycine, lysine, etc. Furthermore, examples of amino acid derivatives include stearoyl glutamic acid, lauroyl lysine, lauroyl glutamic acid, etc. The proportion of amino acids used is not particularly limited, but if it is too small, the surface treatment will be insufficient, and if it is too large, post-treatment will be complicated. Therefore, the proportion is preferably 0.1 to 20 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of silica particles used. As the silicone oil, any known silicone oil that is normally used for surface treatment of silica particles can be used without any particular restrictions, and it may be appropriately selected and used depending on the required performance of the surface-treated silica particles, taking into consideration the application, resin, solvent, and other additives.

[0026] [Silicone oil] Specific examples of silicone oils include dimethyl silicone oil, methylphenyl silicone oil, methylhydrogen silicone oil, alkyl-modified silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, carbinol-modified silicone oil, methacrylic-modified silicone oil, polyether-modified silicone oil, and fluorine-modified silicone oil. The proportion of silicone oil used is not particularly limited, but if it is too little, the surface treatment will be insufficient, and if it is too much, post-treatment will be complicated. Therefore, the proportion is preferably 0.05 to 80 parts by mass, and more preferably 0.1 to 60 parts by mass, per 100 parts by mass of silica particles used.

[0027] [Silane coupling agents] As the silane coupling agent, any known silane coupling agent that is commonly used for surface treatment can be used without any particular limitation, and may be appropriately selected and used depending on the required performance of the surface-treated silica particles, etc. Specific examples of silane coupling agents include methyltrimethoxysilane, methyltriethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxytrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N,N-dimethyl-3-aminopropyltrimethoxysilane, N,N-diethyl-3-aminopropyltrimethoxysilane, and 4-styryltrimethoxysilane. The proportion of the silane coupling agent used is not particularly limited, but if it is too small, the surface treatment will be insufficient, and if it is too large, post-treatment will be complicated. Therefore, the proportion is preferably 0.05 to 80 parts by mass, and more preferably 0.1 to 40 parts by mass, per 100 parts by mass of the silica particles used.

[0028] [Silazan] As the silazane, any known silazane that is usually used for surface treatment can be used without any particular limitation. Specific examples of silazanes include tetramethyldisilazane, hexamethyldisilazane, heptamethyldisilazane, etc. Among these, hexamethyldisilazane is preferred for its reactivity and ease of handling. The proportion of silazane used is not particularly limited, but if it is too small, the surface treatment will be insufficient, and if it is too large, the post-treatment will be complicated. Therefore, the proportion is preferably 0.1 to 150 parts by mass, and more preferably 1 to 120 parts by mass, per 100 parts by mass of the silica particles used.

[0029] [fatty acid] As the fatty acid, any known fatty acid that is commonly used for surface treatment can be used without any particular limitation, and may be appropriately selected depending on the required performance of the surface-treated silica particles. Specific examples of fatty acids that can be used include both saturated and unsaturated fatty acids, such as stearic acid, lauric acid, ricinoleic acid, oleic acid, linoleic acid, etc. Metal salts containing calcium, magnesium, barium, etc. can also be used. The proportion of fatty acid used is not particularly limited, but if it is too small, the surface treatment will be insufficient, and if it is too large, post-treatment will be complicated. Therefore, the proportion is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass, per 100 parts by mass of silica particles used.

[0030] <Application> The type of resin to be blended with the surface-treated amorphous spherical silica of the present invention is not particularly limited and may be appropriately selected depending on the intended use, and examples of the resin include epoxy resin, acrylic resin, silicone resin, and olefin-based resin. For example, for semiconductor encapsulation, liquid crystal sealant, and adhesive applications, epoxy resins, acrylic resins, silicone resins, etc. are preferred. For film applications, olefin-based resins (polypropylene, polyethylene, polystyrene, etc.) are preferred. For paint applications, acrylic resins, silicone resins, etc. are preferred. The amount of surface-treated amorphous spherical silica added to the resin composition may be adjusted as appropriate depending on the application and purpose. Specifically, when used as a semiconductor encapsulant, the amount is preferably 65 to 900 parts by weight per 100 parts by weight of resin; when used as a liquid crystal sealant, the amount is preferably 1 to 40 parts by weight per 100 parts by weight of resin; when used as a film, the amount is preferably 0.01 to 1 part by weight per 100 parts by weight of resin; and when used as a coating material, the amount is preferably 1 to 30 parts by weight per 100 parts by weight of resin. Furthermore, the resin composition may contain other fillers in addition to the surface-treated amorphous spherical silica of the present invention. Cosmetics containing the surface-treated amorphous spherical silica of the present invention may be in various forms, such as powder, cake, pencil, stick, gel, mousse, liquid, and cream, and may include skin cleansers such as soap and makeup remover, skin care cosmetics intended for moisturizing, preventing rough skin, whitening, improving wrinkles and sagging, providing anti-sunscreen effects, and the like, makeup foundations such as powder foundation, pressed foundation, liquid foundation, cream foundation, mousse foundation, loose powder, and makeup base, and point makeup cosmetics such as eye shadow, mascara, and lipstick. When the surface-treated amorphous spherical silica of the present invention is blended into a cosmetic, the amount added is preferably in the range of 0.1 to 30%, and more preferably in the range of 1 to 20%. [Example]

[0031] EXAMPLES In the following, examples are shown to specifically explain the present invention, but the present invention is not limited to these examples. <Amorphous spherical silica (base material)> UF-320: Tokuyama Corporation fused silica Exelica UF-320, average particle size 3.5 μm, specific surface area 1.6 m 2 / g(Reference example 1) UF-725: Tokuyama Corporation's fused silica, Excelica UF-725, average particle size 7.1 μm, specific surface area 1.5 m 2 / g(Reference example 2) SE-8: Tokuyama Corporation's fused silica EXELICA SE-8, average particle size 10.2 μm, specific surface area 1.3 m 2 / g(Reference example 3) SE-15: Tokuyama Corporation's fused silica EXELICA SE-15, average particle size 16.3 μm, specific surface area 1.0 m 2 / g(Reference example 4)

[0032] <Physical property measurement method> The physical properties of each silica were confirmed according to the following methods, and the results are shown in Table 1. (pore volume) The sample to be measured is dried at 200°C for at least 3 hours under a vacuum of 1 kPa or less, and then the adsorption isotherm of only the nitrogen adsorption side at liquid nitrogen temperature is obtained and analyzed by the BJH method (Barrett, EP; Joyner, LG; Halenda, PP, J. Am. Chem. Soc. 73, 373 (1951)).

[0033] (Cumulative 50% volume diameter) The cumulative 50% volume diameter was measured using a Microtrac laser diffraction / scattering particle size distribution analyzer (MT-3300EX2) with a dispersant, and the cumulative 50% volume diameter was calculated. Here, 250 mL of dispersant (pure water for hydrophilic products, ethanol for surface-treated products) and 0.02 g to 0.1 g of sample were placed in the sample slurry circulation tank of the measurement device, and the slurry was ultrasonically dispersed at 40 W for 1 minute while circulating, and the cumulative 50% volume diameter was measured. The sample loading amount was adjusted according to the standard operating procedure of the device so that the slurry concentration value (sample loading value) displayed on the device control computer screen was between 0.85 and 0.90.

[0034] (Amount of particles with a diameter of more than 45 μm) Using a precision electronic balance, 100 g of sample was weighed onto a 45 μm mesh test sieve (JIS Z8801). The sample was sieved for 3 minutes while pouring pure water (for hydrophilic products) or ethanol (for surface-treated products). The silica remaining on the sieve was collected and dried in a thermostatic oven (set temperature: 100°C, drying time: 30 minutes). After cooling to room temperature, the weight (g) of the silica on the sieve was measured using a precision electronic balance, and the amount (%) of particles over 45 μm was calculated using the formula: weight of silica on the sieve / weight of charged silica x 100.

[0035] (value of n in the Rosin-Rammler diagram) The n value obtained when plotting on the Rosin Ramler diagram was measured using a Microtrac laser diffraction scattering particle size distribution analyzer (MT-3300EX2) in a dispersant (ethanol), and the Rosin Ramler n value calculation program built into the analyzer was used. The sample preparation and measurement conditions were the same as those for measuring the cumulative 50% volume diameter.

[0036] (carbon content) The carbon content in the sample was measured by the combustion oxidation method (Sumika Chemical Analysis Center, Sumigraph NC-TR22). Approximately 0.2 g of the sample was heated to 900°C in an oxygen atmosphere, and the carbon content (%) in the sample was determined.

[0037] (crystallinity) Measurements were performed using a multipurpose X-ray diffractometer (Rigaku, SmartLab (9KW)) with a step of 0.02 deg, a speed of 2 deg / min, and a 2Theta range of 10 to 50 deg.

[0038] (Circularity) Approximately 1 mg of sample was placed in the center of a glass slide (2 cm x 4 cm), and 2-3 drops of ethanol were added to create a silica slurry. A cover glass was placed on top of the silica slurry to prevent air bubbles from entering, creating a specimen for observation. Images of the silica particles were captured using a Leica DMLB optical microscope (transmitted light source, 400x magnification), and the circularity (circular equivalent diameter / longest diameter) of each particle was measured using a Leica Q500IW analyzer. Measurements were repeated while moving the observation field until a total of 500 or more particles were measured, and the average of these measurements was used as the circularity value of the silica powder.

[0039] (Oil absorption amount) Measurement was carried out according to the method of JIS K5101-13-1.

[0040] (specific surface area) The specific surface area was measured by the BET single-point method using a specific surface area measuring device (Shimadzu Corporation, Flowsorb III2305) based on the amount of nitrogen adsorption.

[0041] Example 1 80 kg of UF-320 was charged into a 340 L double-cone device (Tokuju Manufacturing Co., Ltd., W-150) and the atmosphere was replaced with nitrogen. Next, 258 g of hexamethyldisilazane (Shin-Etsu Silicone, SZ-31) as a surface treatment agent was added dropwise using a peristaltic pump. After the entire amount of surface treatment agent was added dropwise, the device was operated at a rotation speed of 0.3 rps and mixed at room temperature for 3 hours. The mixed powder was then removed from the apparatus, divided into 10 kg portions, and heat-treated for 3 hours in a nitrogen-purged oven at 150°C to obtain surface-treated amorphous spherical silica A. Its physical properties are shown in Table 1 (the same applies to the following examples).

[0042] Example 2 In Example 1, the silica used was changed to UF-725, thereby obtaining surface-treated amorphous spherical silica B. Otherwise, the surface treatment was carried out in the same manner as in Example 1.

[0043] Example 3 In Example 1, the silica used was changed to SE-8, thereby obtaining surface-treated amorphous spherical silica C. Otherwise, the surface treatment was carried out in the same manner as in Example 1.

[0044] Example 4 A 10 L glass cylindrical container was charged with 2 kg of pure water and 200 g of UF-320. Next, a solution of 20 kg of disodium N-stearoyl-L-glutamate dissolved in 200 g of pure water was added to the glass cylindrical container, and the mixture was mixed at room temperature for 3 hours using a paddle-type stirring blade. Next, solid-liquid separation was carried out using a centrifuge, and the silica cake was dried and heat-treated in a dryer at 110°C for 3 hours to obtain surface-treated amorphous spherical silica D.

[0045] Example 5 In Example 4, a solution prepared by dissolving 10 g of disodium N-stearoyl-L-glutamate in 100 g of pure water was used as the surface treatment solution. Except for this, the surface treatment was carried out in the same manner as in Example 4, to obtain surface-treated amorphous spherical silica E.

[0046] Example 6 200 g of UF-320 was placed in a 1 L heat-resistant and pressure-resistant vessel. The atmosphere inside the vessel was replaced with nitrogen, and 12 g of 1 cSt silicone oil was introduced into the vessel. The vessel was heated to 250°C while rotating and mixing, and pressure surface treatment was carried out for 1 hour to obtain surface-treated amorphous spherical silica F.

[0047] Example 7 Surface-treated amorphous spherical silica G was obtained by carrying out the surface treatment in the same manner as in Example 6, except that the surface treatment agent was changed to methylhydrogenpolysiloxane.

[0048] Example 8 Surface-treated amorphous spherical silica H was obtained by carrying out the surface treatment in the same manner as in Example 1, except that the surface treatment agent was changed to 80 g of γ-glycidoxypropyltrimethoxysilane.

[0049] Example 9 Surface-treated amorphous spherical silica I was obtained by carrying out the surface treatment in the same manner as in Example 1, except that the surface treatment agent was changed to 80 g of methacryloxypropyltrimethoxysilane.

[0050] Example 10 200 g of UF-320 was placed in a 1 L heat-resistant and pressure-resistant container. The atmosphere inside the container was replaced with nitrogen and heated to 80°C. 2 g of stearic acid was heated to 80°C and melted, then introduced into the container. The container was then heated to 150°C while rotating and mixing, and surface-treated for 1 hour to obtain surface-treated amorphous spherical silica J.

[0051] Example 11 200 g of UF-320 was placed in a 1 L heat-resistant and pressure-resistant container. The atmosphere inside the container was replaced with nitrogen, and 2 g of oleic acid was added to the container. The container was heated to 150°C while rotating and mixing, and surface treatment was carried out for 1 hour to obtain surface-treated amorphous spherical silica K.

[0052] (Comparative Example 1) In Example 1, the silica used was changed to SE-15. Otherwise, the surface treatment was carried out in the same manner as in Example 1, and surface-treated amorphous spherical silica L was obtained.

[0053] [Table 1]

[0054] Each silica was subjected to the following evaluations A to D. The results are shown in Table 2.

[0055] <Evaluation A: Viscosity characteristics evaluation> 14 g of the sample was added to 6 g of bisphenol A+F type epoxy resin (ZX-1059, manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.) and mixed by hand. The mixed resin composition was pre-mixed using a planetary centrifugal mixer (THINKY, Awatori Rentaro AR-500) (mixing: 1000 rpm, 8 minutes; degassing: 2000 rpm, 2 minutes). The pre-mixed resin composition was then mixed using a three-roll mill (IMEX, BR-150HCV, roll diameter φ63.5 mm). Mixing conditions included a roll distance of 20 μm, five mixes, and room temperature. The viscosity of the kneaded resin composition was measured using a rheometer (ReoStress, manufactured by HAAKE) at a rotation speed of 2 s −1 and at 25° C.

[0056] <Evaluation B: Feeling evaluation using a friction tester> The sample to be measured was 0.5 mg / cm for artificial leather (Sapler PBZ, manufactured by Ideax Japan). 2 The average coefficient of friction (MIU) and the variation in the average coefficient of friction (MMD) were evaluated using a friction tester (Kato Tech, KES-SE). Measurement conditions were a 10mm square silicone sensor, a sensor movement speed of 1mm / sec, an end point load of 60g, an ambient temperature of 20±1°C, and an ambient humidity of 65±5%. The lower the MIU, the better the slipperiness, and the lower the MMD, the less roughness there is.

[0057] <Evaluation C: Sensitivity evaluation by panelists (surface-treated amorphous spherical silica)> Ten panelists evaluated the feel of the prepared samples or surface treatment products when they were applied to their own skin. The evaluation items were low dryness, low roughness, slipperiness, and low roughness, and each panelist evaluated each item according to the following evaluation criteria (a). (Evaluation criteria a) 3 points: Excellent 2 points: normal 1 point: Inferior The total score of these evaluation criteria was calculated and graded based on the following evaluation criteria (b). (Evaluation Criterion B) 26~30 points: 5 21~25 points: 4 16~20 points: 3 11~15 points: 2 6~10 points:1 1~5 points: 0

[0058] <Evaluation D: Sensitivity evaluation by panelists (loose powder)> 5.0% by mass of surface-treated amorphous spherical silica, 5.0% by mass of fine particle titanium oxide, 5.0% by mass of fine particle zinc oxide, 10.0% by mass of pigment-grade titanium oxide, 0.1% by mass of red iron oxide, 0.1% by mass of yellow iron oxide, 0.1% by mass of black iron oxide, and 74.7% by mass of mica were mixed to obtain the compounding ratio shown below, and pulverized in a mortar to prepare a loose powder, which was evaluated in the same manner as in Evaluation C.

[0059] [Table 2]

[0060] From the evaluation A, for Examples 1, 2, 8, 9, and 10, the viscosity of the resin compound could be reduced by performing surface treatment. This allows for higher filler loading, improving the reliability of the resin composition. Note that SE-8 and SE-15, which have large particle sizes and contain coarse particles, could not be kneaded at a gap of 20 μm. From the results of the evaluations B, C, and D, it was confirmed that the particle properties and smoothness were improved by the surface treatment. Furthermore, in Examples 4 to 7, 10, and 11, the feel when used in cosmetics was also improved, confirming the effect of the surface treatment. The surface-treated amorphous spherical silica of the present invention can reduce the viscosity of resin compounds and allow for high filler loading, making it suitable for use in resin compositions, sealants, and adhesives. Furthermore, the low content of coarse particles improves film formability and reduces the likelihood of poor appearance in films and paints, making it suitable for use. Furthermore, since it does not contain crystalline silica, it provides an improved feel when applied to the skin or used as a loose powder, making it suitable for use in cosmetics.

Claims

1. Surface-treated amorphous spherical silica that satisfies all of the following physical properties: (1) The pore volume measured by nitrogen adsorption is 0.05 mL / g or less (2) A cumulative 50% volume diameter measured by laser diffraction is 1 to 20 μm. (3) The amount of particles with a particle size of more than 45 μm measured by the wet sieve method is 2% by mass or less (4) The particle size measured by laser diffraction is plotted on a rosin Ramler diagram, and the value of n is 1.5 to 3.

0. (5) Carbon content is 0.01% or more and 5.00% or less. (6) Crystallinity is less than 0.1% (7) Circularity of 0.80 or more

2. 2. The surface-treated amorphous spherical silica according to claim 1, wherein the surface-treated amorphous spherical silica has an oil absorption of purified linseed oil of 30 mL / 100 g or less, as determined by the test method described in JIS K5101-13-1.

3. A resin composition comprising the surface-treated amorphous spherical silica according to claim 1 or 2.

4. A sealing material comprising the surface-treated amorphous spherical silica according to claim 1 or 2.

5. 3. An adhesive comprising the surface-treated amorphous spherical silica according to claim 1 or 2.

6. A film using the surface-treated amorphous spherical silica according to claim 1 or 2.

7. A cosmetic preparation comprising the surface-treated amorphous spherical silica according to claim 1 or 2.

8. A paint comprising the surface-treated amorphous spherical silica according to claim 1 or 2.

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