JPH1111927A - Composite particle with silica matrix, its production and compounded cosmetic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain composite particles which show excellent spreading property, orienting property, shielding property, etc., when the particles are compounded in a cosmetic material or the like, which show properly controlled aggregating property of metal (compd.) fine particles and catalytic reactivity, and which are excellent in such a use as to shield from UV rays, by surrounding metal (compd.) fine particles with silica having a specified or smaller percentage of a crystalline isolated silicate amt. to make a composite material. SOLUTION: The silica used has <10% crystalline isolated silica measured by X-ray diffraction analysis. The metal (compd.) fine particles have 0.01 to 0.5 μm primary particle size. The primary particles of the composite particles preferably substantially have a flake-like form. Each flake-like particle has 0.001 to 1 μm thickness and at least 5 ratio (aspect ratio) of the max. length of the flake to the thickness. The composite particles are obtd. by using a silica sol as the starting material obtd. by dealkalization of an alkali silicate soln., dispersing the metal (compd.) fine particles in the sol, and subjecting the silica sol to hydrothermal treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a metal plate or a metal compound having a function of shielding ultraviolet rays, which is encapsulated in low-crystalline silica which is harmless to the human body, and is preferably formed into a composite, preferably in the form of a scale plate. The present invention relates to a silica composite particle having the same, a method for producing the same, and a cosmetic containing the same.

[0002]

2. Description of the Related Art In recent years, the harmfulness of ultraviolet rays to skin has been attracting much attention due to the problem of destruction of the ozone layer. It has been found that exposure to ultraviolet light can cause inflammation, skin pigmentation, wrinkles, spots, and other aging of the skin, as well as the risk of skin cancer by damaging the genes of skin cells. Was. In the past, people said, "If you tan, you won't catch a cold," but according to dermatologists, these are also completely superstitions,
Sunburn reduces the immunity of the whole body.
At present, 80% of skin wrinkles and wrinkles are attributed to exposure to ultraviolet light, and it has been described in numerous dermatological literature that the adverse effects of ultraviolet light are more than expected. It is clear from that.

[0003] In addition, when exposed to direct sunlight, not only living organisms but also resins and paints are affected by ultraviolet rays and deteriorate with time due to the direct oxidation of ultraviolet rays.

[0004] Metal oxide fine particles such as titanium dioxide, zinc oxide, cerium oxide and iron oxide are known as substances having a large ultraviolet shielding effect. However, they have a photocatalytic oxidation action and can be used only for cosmetics, paints, and the like. When incorporated in a resin or the like, there has been a problem that the constituent components are oxidized, causing deterioration and alteration.

[0005] Generally speaking, since these are fine particles, they are extremely easily aggregated, and are used in cosmetics, paints,
Practically, it is very difficult to uniformly or homogeneously disperse the resin in a resin, and there is a major problem that it is not easy to sufficiently fulfill the inherent ultraviolet ray shielding function of the resin.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-crystalline silica base material having a sufficiently small amount of crystalline free silicic acid, which is harmful from the viewpoint of occupational safety and health. An object of the present invention is to provide silica-composite particles in which metal or metal compound fine particles that are extremely easily aggregated and whose catalytic reaction activity is difficult to control are included and are composited, and a method for producing the same. The silica-based composite particles of the present invention are preferably in the form of scale-like plates, cosmetics,
When blended in paints, resins, etc., spreadability (extensibility), orientation, excellent properties such as concealing properties, the cohesion and catalytic reactivity of the metal or metal compound fine particles are appropriately controlled, It is extremely excellent for ultraviolet shielding and other uses.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the importance of the above-mentioned problems, and have found that fine particles of a metal or a metal compound are dispersed in a silica sol as a starting material containing a silica source and an alkali source. Surprisingly, by performing the hydrothermal treatment in a state where the fine particles of the metal or metal compound are encapsulated by silica, composite particles based on silica are obtained, and preferably, It has been found that composite particles having a scale-like plate shape can be obtained. Furthermore, when a metal or metal compound fine particle having a function of shielding light in a specific wavelength region, for example, an ultraviolet ray shielding function is used, the composited composite particles themselves exhibit a higher ultraviolet ray shielding function and the like. I found that. Further, in this case, the metal or the metal compound has a problem of decomposing, altering, or deteriorating an organic substance or the like which comes into contact with the metal or the like due to a photocatalytic oxidation action. It has been found that, since they are composited, organic substances and the like which come into contact with the composited particles are less likely to be decomposed, deteriorated, or degraded.

[0008] Such silica composite particles are sufficiently safe, for example, when blended in cosmetics, because the silica as a base material has a sufficiently low content of crystalline silicic acid harmful to the human body. Further, preferably, since this is in the form of a scale plate, spreadability, orientation, and excellent properties such as concealing properties, the composite particles, the metal fine particles and the like, is encapsulated in silica and composite. In order to complete the present invention, it has been found that in a matrix such as a cosmetic, a cosmetic having a higher ultraviolet shielding function and a more suppressed photocatalytic oxidation action can be obtained without being agglomerated any more. It has arrived.

That is, the object of the present invention is to provide (1)
Composite particles in which metal or metal compound fine particles are encapsulated by silica to form a composite, wherein the silica has a measured value of free crystalline silicic acid of less than 10% by X-ray diffraction analysis. A silica-based composite particle, (2) a cosmetic prepared by blending the composite particle, and (3) a silica sol obtained by dealkalization of an alkali silicate aqueous solution, using as a starting material a metal or A method for producing the composite particles, wherein the silica sol is subjected to hydrothermal treatment in a state where the metal compound fine particles are dispersed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The silica-based composite particles of the present invention (
Hereinafter, they may be simply referred to as silica composite particles. )
Composite particles comprising metal or metal compound fine particles encapsulated in silica to form a composite, and the silica has a measured value of free crystalline silicic acid of less than 10% by X-ray diffraction analysis. And

First, silica, which is the base material of the composite particles,
When the measured value of crystalline free silicic acid measured by the X-ray diffraction analysis method described below is less than 10%, preferably less than 5%, and more preferably 2% (below the detection limit), it is very slight low crystalline silica. is there.

The significance of the measured value of the crystalline free silicic acid will be described. Generally, crystalline silica, such as quartz, cristobalite or tridymite, is classified as crystalline free silicic acid.When inhaled as dust in human lungs for a long period of time, it is deposited on the lungs and surrounding tissues and is difficult to treat. It has been confirmed pathologically to cause silicosis, which is regulated by the Pneumoconiosis Law and the Pneumoconiosis Law on occupational safety and health. On the other hand, amorphous silica such as silica gel is classified as amorphous free silicic acid, but it is also known that the amorphous type is significantly less likely to cause silicosis than the crystalline type. , 10, 25-40 (1980)).

Free silicic acid is a name distinguished from bonded silicic acid constituting silicate, in which silicon is three-dimensionally bonded only to oxygen and not bonded to other elements.
In short, it means silicon dioxide (SiO ₂ ). Such free silicic acid is classified into the above-mentioned amorphous type, crystalline type, and the like. Among them, the crystalline type free silicic acid that causes silicosis can be quantified by X-ray diffraction analysis or the like. ,
More specifically, the X-ray diffraction analysis described in the Work Environment Measurement Guidebook (Mineral Dust-Related Ministry of Labor, Health and Safety Department, Environmental Improvement Office), based on the work environment measurement standards indicated in the notification on the Industrial Safety and Health Law It is measured by the method.

As described above, the silica which is the base material of the composite particles of the present invention has a crystalline free silicic acid value of less than 10%, preferably less than 5%, as measured by X-ray diffraction analysis.
As is clear from the fact that it is more preferably 2% (below the detection limit), even if silica fine particles are inhaled into the respiratory tract of a human body, it is considered that harm to the human body is extremely small. Because it is low crystalline silica,
Its safety is high enough.

In the silica of the present invention, so-called amorphous tailing is hardly observed when measured by X-ray diffraction analysis.

Conventionally, crystalline silica, which is called silica X in the sense that a peak is produced in X-ray diffraction, has been known (Beitr. Mineral. Petrogr. 10, 242-259 (19)
64)), although these are in the form of a large number of flaky particles coalesced, they are non-porous and poorly reactive, and it is virtually impossible to support them with specific substances or use them as fillers. It is difficult.

On the other hand, the silica as the base material of the composite particles of the present invention preferably has an IR spectrum of 3600 to
It is a low crystalline silica having a silanol group having one absorption band at 3700, 3400 to 3500 cm ^-1 . For this reason, since the composite particles have silanol groups having high reaction activity on the surface thereof, it is possible to chemically modify the composite particles with a desired organic component, for example, to further enhance the function as a filler for cosmetics. Is also possible.

The composite particles comprising silica as a base material of the present invention are obtained by encapsulating and complexing fine particles of a metal or a metal compound with the above-mentioned silica.

The term “encapsulation” as used herein means, for example, that a large number of fine particles of a metal or a metal compound are dispersed and integrally taken in, for example, scale-plate-like particles.

In the present invention, it is preferable that the primary particles of the composite particles are composite particles basically having a scale plate shape.

The scale-plate-like composite particles have a thickness of 0.00
It is composed of a scale plate having a length of 1 to 1 μm, preferably 0.01 to 0.5 μm, and the ratio of the longest length of the scale plate to the thickness (aspect ratio) is at least 5, preferably 10 or more, more preferably 30 or more. Is a composite particle having a scale plate-like silica as a base material having the following.

When the thickness of the scale plate is less than 0.001 μm, the mechanical strength of the scale plate is insufficient, which is not preferable. On the other hand, when the thickness of the scale plate is larger than 1 μm, the spreadability when blended in a cosmetic or the like may be insufficient, which is not preferable. Further, when the aspect ratio is less than 5, the spreadability may become insufficient similarly, which is not preferable.

Although the upper limit of the aspect ratio is not particularly specified, it is usually practically 300 or less, preferably 200 or less.

Unless otherwise specified, the thickness and length of the scale plate-like silica in the present invention mean the average value of the primary particles.

Here, the scaly plate shape may be any shape as long as it has a substantially plate shape, and may be partially or wholly bent or twisted.

The silica composite particles aimed at by the present invention are produced as follows.

That is, a silica sol is used as a starting material, and a metal or a metal compound fine particle to be included in the silica composite particles is added to and dispersed in the silica sol, and heated in a heating pressure vessel such as an autoclave or the like. The heat treatment is performed. In this way, silica composite particles containing silica as a base material, in which the metal or metal compound fine particles are encapsulated in silica and composited, are produced. In addition,
The metal or metal compound fine particles used in the present invention will be described later in detail.

In the present invention, a starting material is a silica sol containing specific amounts of a silica source and an alkali source. In particular, the silica / alkali molar ratio (SiO ₂ / Me ₂ O, wherein M
e represents an alkali metal such as Li, Na or K. same as below. ), A silica sol obtained by dealkalizing an aqueous solution of an alkali silicate of 1.0 to 3.4 mol / mol by an ion exchange resin method or an electrodialysis method is preferably used. As the alkali silicate aqueous solution, for example, a solution obtained by appropriately diluting water glass with water is preferably used.

The silica / alkali molar ratio (SiO ₂ / Me ₂ O) in the dealkalized silica sol as a starting material
Is preferably in the range of 3.5 to 20 mol / mol,
The range of 4.5 to 18 mol / mol is more preferred.
If it is less than 3.5 mol / mol, the solubility of silica increases and the yield deteriorates, which is not preferable. On the other hand, 20
If it exceeds mol / mol, the stability of the silica sol is undesirably reduced.

The silica concentration in the silica sol is preferably 2 to 20% by weight, particularly preferably 3 to 15% by weight. If the concentration is lower than 2% by weight, productivity is undesirably reduced. On the other hand, if it exceeds 20% by weight, the stability of the silica sol is undesirably reduced.

The silica particle diameter in the silica sol means an average particle diameter, and is not particularly limited.
The following are preferred, and among them, so-called activated silicic acid of 20 nm or less is particularly preferred. The lower limit of the particle size is not particularly limited, but is preferably 0.5 nm or more. If the particle size is too large, exceeding 100 nm, the stability of the silica sol is undesirably reduced. In addition,
The method of measuring the silica particle diameter is not particularly limited as long as the particle diameter in this range can be measured, and may be a laser light scattering particle size measuring apparatus or a scale measurement of a particle image size taken by a transmission electron microscope. Can be measured.

In the present invention, the above-mentioned silica sol is used as a starting material, and the following metal or metal compound fine particles are added to and dispersed in the silica sol, and the dispersion is heated in a heating pressure vessel such as an autoclave to perform hydrothermal treatment. By performing the above, composite particles containing silica as a base material in which the metal or metal compound fine particles are encapsulated by silica and composited are produced.

The metal fine particles to be added to the starting material silica sol are not particularly limited.
Platinum, copper, boron, aluminum, gallium, indium, iron, ruthenium, osmium, nickel, palladium, cobalt, rhodium, iridium, zinc, tin, manganese, technetium, titanium, zirconium, silicon, cerium, molybdenum, tantalum, niobium, hafnium,
Fine particles such as activated carbon and carbon black are exemplified as preferable ones.

The metal fine particles referred to in the present invention also include fine particles of an alloy mainly composed of these metals. For example,
Aluminum-magnesium alloy, iron-carbon alloy, iron-
Fine particles such as copper alloy, iron-nickel-chromium alloy, silver-gold alloy, palladium-gold alloy, silver-palladium alloy, copper-nickel alloy, nickel-cobalt alloy, nickel-magnesium alloy, and tin-lead alloy are exemplified. You.

On the other hand, fine particles of the metal compound include zinc oxide, titanium oxide, titanium peroxide, zirconium oxide,
Chromium oxide, aluminum oxide, magnesium oxide, silver oxide, ferrous oxide, ferric oxide, cuprous oxide, cupric oxide, cobaltous oxide, cobalt trioxide, cobaltous oxide, primary oxide Nickel, nickel (II) oxide, thorium oxide, tungsten oxide, molybdenum oxide, manganese dioxide, manganese trioxide, uranium oxide, thorium oxide,
Oxides such as zinc sulfide, stannous oxide, stannic oxide, lead monoxide, lead tetroxide, lead dioxide, antimony trioxide, antimony pentoxide, bismuth trioxide, oxides such as germanium oxide; cadmium sulfide , Zinc sulfide, antimony sulfide,
Sulfides and sulfates such as calcium sulfide, silver sulfide, mercury sulfide, germanium sulfide, cobalt sulfide, tin sulfide, lead sulfide, nickel sulfide, manganese sulfide, zinc sulfide, lead sulfate, barium sulfate, strontium sulfate, and calcium sulfate; Nitride such as boron, magnesium nitride, aluminum nitride, titanium nitride, tantalum nitride, silicon nitride; tantalum carbide, zirconium carbide, tungsten carbide, molybdenum carbide, hafnium carbide, chromium carbide, vanadium carbide, silicon carbide, titanium carbide, boron carbide , Uranium carbide,
Fine particles such as carbides and halides such as beryllium carbide and calcium fluoride are preferred.

These metals or metal compounds may be composed mainly of one of them, to which a small amount of a so-called dopant component or impurity component is added. For example, a small amount of a metal element such as iron, aluminum, zinc, sodium, potassium, magnesium, and phosphorus may be added to titanium dioxide.

Each of these fine particles is a shielding material for light having a specific wavelength such as ultraviolet light, a photocatalyst, an antibacterial material, a photoelectric element,
It is suitably used for EL elements, semiconductor elements, non-linear elements, and the like, and commercially available ones can be easily obtained. Further, since the particle diameter is extremely small, it has a large surface area and is highly active, and its function of shielding light of a specific wavelength, photocatalytic function, antibacterial function, photoelectric function and the like is extremely large. However, on the other hand, since they are small fine particles, they have strong cohesiveness, and it is extremely difficult to uniformly disperse them as primary particles in cosmetics, paints, resin media and matrices, and they sufficiently fulfill their inherent functions. It is difficult to exercise, and because of the fine particles,
In some cases, the surface activity is too high to control photocatalytic and antibacterial functions, and cosmetics, paints,
There has been a problem that these components are altered or an odor is generated due to an oxidation reaction or the like with the components of the resin medium or the matrix.

The fine particles of a metal or a metal compound in the present invention include what is called ultrafine particles, and the size (particle size) of the primary particles is 0.01 to 0.5 μm.
m. And what is 0.03-0.3 micrometers is more preferable. When it is less than 0.01 μm,
Since the specific surface area is increased, it is in an uncontrollable aggregation state from the beginning, and it is not possible to encapsulate the fine particles in a silica substrate in a sufficiently dispersed state to form a composite, thereby failing to obtain a desired ultraviolet shielding function or the like. 0.5 μm
If it exceeds, not only the ultraviolet ray shielding function of the fine particles themselves is reduced, but also the metal compound fine particles are not sufficiently encapsulated and complexed with the flaky silica as a base material, for example, suppression of photocatalytic oxidation action. Is not preferred because the effect of suppressing the photocatalytic oxidation action described below decreases.

In the present invention, it is preferable that the fine particles of the metal or metal compound are basically spherical, and in this case, the particle diameter indicates a diameter. However, non-spherical particles such as irregular or needle-shaped particles may be used. In such a case, the particle diameter refers to the maximum diameter.

The content ratio of the metal or metal compound fine particles in the composite particles is preferably from 1 to 50% by weight, particularly preferably from 2 to 35% by weight. If the content ratio is less than 1% by weight, the function to be performed by the metal or metal compound fine particles, for example, the ultraviolet shielding effect cannot be sufficiently obtained, which is not preferable. On the other hand, when the content exceeds 50% by weight, a part or a considerable part of the metal or metal compound fine particles is encapsulated in the silica base material and is not composited, so that it is exposed.
The desired effect of suppressing photocatalytic oxidation and the like is undesirably reduced. Therefore, so that the above content ratio,
The amount of silica in the starting material and the metal or metal compound fine particles to be added are adjusted.

As one preferred embodiment of the present invention,
The metal or metal compound fine particles have a function of shielding light in a specific wavelength region. Here, the light blocking function means a function in which light in a specific wavelength region is absorbed and / or scattered by the fine particles, and the light in a certain wavelength region of the irradiated light is substantially blocked. For example, X-ray shielding function, visible light shielding function, infrared ray shielding function,
It has a function of shielding ultraviolet rays.

Here, the ultraviolet shielding function will be described as an example.

In the present invention, the fine particles of a metal or a metal compound having an ultraviolet shielding function to be added to the silica sol as a starting material are not particularly limited. For example, titanium dioxide, cerium oxide, zinc oxide, iron oxide, etc. Are suitable, and these can be used alone or as a mixture. In this case, if the added fine particles having an ultraviolet shielding function are aggregated,
Since the ultraviolet ray shielding function cannot be sufficiently exhibited and the performance is deteriorated, the fine particles are added to silica sol or water for concentration adjustment, and then subjected to a dispersion treatment using a high-speed shearing disperser, a medium stirring mill, an ultrasonic disperser or the like. It is preferable to disperse sufficiently in silica sol.

In order to hydrothermally treat the silica sol, it is possible to adjust the silica concentration to a desired range by adding purified water such as distilled water or ion-exchanged water before charging the autoclave.

The type of the autoclave is not particularly limited, but any autoclave having at least a heating means, a stirring means and preferably a temperature measuring means may be used.

As described above, the raw material obtained by adding and dispersing the metal or metal compound fine particles to the silica sol is subjected to hydrothermal treatment in an autoclave, and the metal or metal compound fine particles are encapsulated and compounded by silica. A composite particle based on silica is produced. The composite particles preferably have a scale plate shape.

In the present invention, the hydrothermal treatment is performed at 150 to 250.
C., and preferably 170-220.degree. If the temperature is lower than 150 ° C., it takes a long time to obtain the desired silica composite particles, which is not preferable. On the other hand, when the temperature exceeds 250 ° C., it is difficult to obtain particles having a desirable scale plate shape. This is because low-crystalline silica X having a scale-like shape is considered to be a metastable phase, and with the progress of hydrothermal treatment, there is a tendency to sequentially transition to cristobalite and quartz. In the case of exceeding, it is considered that a mixture with cristobalite and quartz having high crystallinity is easily generated.

The required time for the hydrothermal treatment may vary depending on the temperature of the hydrothermal treatment, the presence or absence of the addition of seed crystals, etc., but is usually 5 to 50 hours, preferably 5 to 40 hours, more preferably 5 to 40 hours. It is about 25 hours.

In the present invention, the addition of a seed crystal is not essential for efficiently proceeding the hydrothermal treatment and shortening the treatment time, but it is more preferable to add a seed crystal. The addition amount of the seed crystal is not particularly limited, but is 0.001 to 1% by weight based on the charged amount of the raw material silica sol.
The degree is preferred.

As described above, the raw material obtained by adding and dispersing the metal or metal compound fine particles to the silica sol is subjected to hydrothermal treatment in an autoclave, and the metal or metal compound fine particles are encapsulated by silica to form a composite. Is formed, and the mechanism is presumed to be roughly as follows.

In the process of hydrothermal treatment in a state in which the silica fine particles and the metal or metal compound fine particles in the silica sol charged in the autoclave coexist, fine ones of the fine silica particles are so-called Ostwald Ripening.
) Is repeated to grow into larger silica particles. And finally, it grows into a preferable squamous plate-like particle. In the process, the silica particle growth occurs also on the surface of the metal or metal compound fine particles. Alternatively, the metal compound fine particles are taken into the grown silica particles and are composited. In terms of a model, for example, a large number of metal or metal compound fine particles are dispersed and integrally taken in, for example, scale plate-like particles.

It is known that silica is precipitated on the surface of individual metal or metal compound fine particles to form a thin silica film. The original metal or metal compound fine particles having only a thin film formed thereon are supported almost as they are, and are fundamentally different from the composite particles of the present invention.

The composite particles as the object of the present invention can be obtained by filtering, washing, drying and dispersing the hydrothermally treated product thus obtained.

First, after the completion of the hydrothermal treatment, the hydrothermally treated product is taken out of the autoclave, filtered and washed with water. The particles after the water washing treatment have a p
H is preferably 5 to 9, and more preferably pH is 6 to 8.

Basically, by drying this,
The low-crystalline silica composite particles used in the present invention are finally obtained. When the hydrothermally treated product cake is viewed microscopically in a state of being filtered and washed with water, a portion forming aggregated particles (secondary particles) such that individual primary particles have coalesced is observed. If necessary, an operation of loosening the aggregated particles before drying and dispersing them as primary particles, that is, a dispersion treatment (crushing treatment) can be performed. However, in the case of a use as a powder to be added to cosmetics, etc., even if the obtained particles are directly incorporated into cosmetics without dispersion treatment, a sufficiently excellent effect can be obtained. Processing is not necessary.

The method of performing the dispersion treatment is not particularly limited, but may be a mechanical dispersion method using an ultrasonic homogenizer, a wet bead mill, or the like.
A chemical dispersion method using an alkali such as caustic soda and caustic potash is also effective. The mechanism of the manifestation of the effect in this chemical dispersion method is that the so-called readily soluble silica component present as a binder at the coalescing portion of each particle is dissolved by the addition of the alkali, so that each primary particle is separated from each other. , Is assumed to be dispersed.

The drying operation after the dispersion treatment is performed as it is or after washing with a low boiling organic solvent such as acetone or methanol to replace the adhered water with a solvent. Although the drying apparatus is not particularly limited, a flash dryer, a fluidized bed dryer, a medium fluidized bed dryer, a stirring type dryer, a cylindrical dryer, a box type dryer, a band dryer, a hot air dryer, and a vacuum dryer Any device such as a dryer and a vibration dryer can be adopted. In addition, it is usually preferable to perform the drying at a temperature of about 50 to 300 ° C.

The product after drying may form agglomerated particles (secondary particles) as if the individual primary particles were coalesced. As described above, as a powder or the like to be added to cosmetics or the like, even if the obtained particles are directly blended into cosmetics, a sufficiently excellent effect can be obtained, so that dispersion treatment (crushing treatment) is not always necessary. Absent. As a precautionary measure, an arbitrary method such as a ball mill, a bead mill, a hammer mill, a blade mill, a pin mill, and a roller mill can be selected as a dispersion processing apparatus for performing the dispersion processing.

In the present invention, the physicochemical analysis of the silica-based composite particles obtained as described above is performed as follows.

That is, the silanol groups present on the surface of the silica composite particles can be obtained from the IR spectrum.
The aspect ratio of the primary particles can be determined by applying a scale or the like to a sufficiently large number of composite particle images taken by a scanning electron microscope and measuring the thickness and the longest length.

Further, the crystalline form of free silicic acid is described in a work environment measurement guidebook (in relation to mineral dust related to the environment improvement room of the Ministry of Health, Labor and Welfare, Ministry of Labor) related to the work environment measurement standards indicated in the notification on the Industrial Safety and Health Law. It is measured by X-ray diffraction analysis.

Further, the evaluation of the light shielding function such as the ultraviolet shielding performance of the composite particles obtained by the production method of the present invention is performed as follows. That is, the composite particles 0.4
A paste obtained by dispersing 0 parts by weight in 1.12 parts by weight of petrolatum and 0.48 parts by weight of liquid paraffin using three rolls and measuring the spectral transmittance at a wavelength of 25 μm at each wavelength. It is. Specifically, 1.12 g of petrolatum and 0.48 g of liquid paraffin were added to 0.4 g of the composite particles, and a paste obtained by well dispersing using a three-roll mill was obtained. It is sandwiched between two 1 mm quartz plates and spread to a layer thickness of 25 μm to form a measurement sample. The measurement material is, for example, using a self-recording spectrophotometer manufactured by Hitachi, Ltd. and having a wavelength of 200 to 700 nm. Measure the spectral transmittance of the range. When ultraviolet shielding performance is intended, the spectral transmittance at a wavelength of 320 nm is 20%.
However, according to the present invention, the object can be achieved with a small amount of added composite particles. On the other hand, in the case of conventional ultraviolet shielding particles, more particles must be added to the cosmetic, so that the cosmetic becomes hard and whitish.

On the other hand, when titanium oxide or the like having a photocatalytic oxidation action is used as the metal or metal compound fine particles, the photocatalytic activity of the silica composite particles obtained by the production method of the present invention is measured by measuring the titanium oxide-physical properties. And applied techniques (published by Gihodo Publishing). That is, by irradiating isopropyl alcohol with ultraviolet light in the presence of a photocatalyst, the amount of acetone generated by oxidation is determined. Specifically, the volume 50c
a transparent glass bottle m ^3, isopropyl alcohol 2
5 cm ³ and a measurement sample having a sample weight equivalent to 0.18 g of the contained titanium dioxide were put therein, sealed, and exposed to direct sunlight for 24 hours continuously with stirring with a stirrer at room temperature.
The amount of acetone produced is quantified by gas chromatography, and this is a value expressed as the concentration in isopropyl alcohol. In the composite particles of the present invention, the concentration of formed acetone defined as described above is 0.05% by volume or less. In the case of other photocatalytic metals, the measurement is performed according to this.

In the composite particles of the present invention, it can be confirmed by the following method that the metal or metal compound fine particles are encapsulated by silica.

For example, the case where titanium dioxide is used as the metal compound is as follows. A measurement sample of 0.1 g of a silica-based composite particle in which titanium dioxide fine particles are encapsulated and composited, and 10 cm of sulfuric acid (65% by weight) was added thereto.
³ and an aqueous solution of ammonium sulfate (10% by weight) 10 cm ³
Is added and boiled with a burner for 5 minutes to dissolve the soluble components of titanium dioxide. (The method of dissolving titanium dioxide using sulfuric acid and ammonium sulfate is the most reliable method described in the Analytical Chemistry Handbook, etc.) Is). After separating the insoluble matter with a filter paper (5C), the concentration of the eluted titanium dioxide in the filtrate was determined using Oxinol Orange as an indicator.
Quantify by DTA titration. If titanium dioxide is encapsulated in silica and complexed, and the titanium dioxide particles are not exposed on the outer surface of the complexed particles, the amount of titanium dioxide eluted by the above method should be extremely small. On the other hand, if the complexation is not sufficient and a considerable portion of the titanium dioxide is exposed on the surface of the composite particles, it is estimated that a considerable amount of titanium dioxide elutes.

When other metal or metal compound fine particles are used, it can be confirmed that the fine particles are encapsulated and complexed with silica according to this method.

The silica composite particles obtained by the present invention have various uses. For example, when the metal or metal compound fine particles have an ultraviolet shielding function,
It can be blended as an ultraviolet shielding material such as a paint or a resin.

The cosmetics to which the composite particles of the present invention are blended include foundations, emulsions, lotions, creams, pastes, sticks, lipsticks, cheeks, eye shadows, body powders, eyebrows, eyeliners, mascaras. ,
It is a conventionally manufactured cosmetic such as white powder, antiperspirant, shampoo, rinse and mousse, and can be suitably blended with these.

The above-mentioned cosmetics include oils and fats such as petrolatum, liquid paraffin, lanolin, wax and fatty acid esters, organic solvents such as ethanol, isopropanol and glycerin, emulsifiers such as triethanolamine, other silicones, and thickeners. It may contain cosmetic auxiliaries usually used in cosmetics such as agents, fragrances, preservatives, preservatives, surfactants, sequestering agents, dyes, pH adjusters, humectants and the like.

When the silica composite particles of the present invention are blended with a resin, examples of the resin include vinyl chloride resin, vinylidene chloride resin, polyethylene, polypropylene, polystyrene, ABS resin, polycarbonate, nylon, polyacetal resin, polyamide resin, and polyimide resin. resin,
Melamine resins, silicone resins, acrylic resins, methacrylic resins, phenolic resins, polyester resins, urea resins, and fluororesins.

Examples of the coating resin to be incorporated into the coating include polyvinyl alcohol resin, vinyl chloride-vinyl acetate resin, acrylic resin, epoxy resin, alkyd resin, polyester resin, urethane resin, polyamide resin, and polyimide resin. , Phenolic resins and amino resins, which are dispersed in water or an organic solvent to obtain a coating.

When incorporated into cosmetics, resins, paints, and the like, the surface of the silica composite particles of the present invention may have a silicone oil, silane coupling agent, titanate coupling agent, alcohol, surfactant, or other surface treatment. Those surface-treated with an agent or a surface modifying agent can also be suitably used. Those treated and hydrophobized on the surface improve the cosmetic durability when blended into cosmetics. In addition, when treated with a coupling agent, when blended with a resin, the strength is improved and the dispersion stability is increased.

In the silica composite particles of the present invention, when metal or metal compound fine particles having antibacterial properties are used, they act as antibacterial agents. Examples of such metal or metal compound fine particles include copper, silver, zinc, titanium, tin, and oxides and peroxides thereof.

[0075]

According to the low crystalline silica composite particles of the present invention, the crystalline form of free silicic acid which causes silicosis is reduced to a work environment in accordance with the work environment measurement standards indicated in the notification on the Industrial Safety and Health Law. The X described in the measurement guidebook (Mineral Dust Related Environment and Safety Department, Ministry of Labor Safety and Health Department)
It is indicated by a value measured by a line diffraction analysis method, and this value is less than 10%, preferably 5%
It is extremely low, less than 2% (less than the detection limit), more preferably 2% (below the detection limit), and can be said to be extremely safe.

In the silica composite particles of the present invention, the metal or metal compound fine particles are encapsulated by silica to form a composite. However, these metal or metal compound fine particles are inherently extremely fine, and therefore have a strong cohesiveness. If they are used alone, they can be uniformly dispersed as primary particles in a medium or matrix of cosmetics, paints, resins. Is extremely difficult, and it is difficult to sufficiently exhibit the inherent ultraviolet shielding function and the like. However, according to the present invention, these metals or The metal compound fine particles are stably in the form of composite particles having the most preferable scale plate shape or the like as a whole. Therefore, the silica composite particles of the present invention have a high ultraviolet shielding effect and the like, and have a long persistence.

The silica-composite particles of the present invention preferably have a scale-like shape, and are basically oriented, concealed, spreadable and extensible due to the particle shape. Excellent usability.

Furthermore, in the prior art, since the metal fine particles and the like are fine particles, their surface activity is too high to control the photocatalytic function and the like, and cosmetics, paints, resin media and the like containing these are not controlled. According to the present invention, these metal or metal compound fine particles are encapsulated by silica, although there has been a problem that the components of the matrix undergo an oxidation reaction or the like to change the quality of these components or generate an unpleasant odor. The metal or metal compound fine particles come into direct contact with a matrix component of cosmetics or the like when mixed in cosmetics or the like since there is almost no portion exposed on the surface of the composite particles. Without
The photocatalytic oxidizing action that is too strong can be appropriately controlled to prevent oxidation, alteration, generation of an unusual odor, and the like of the matrix component.

Further, the silica of the present invention preferably comprises
3600-3700, 3400-35 of IR spectrum
It has a silanol group having one absorption band at 00 cm ^-1 . Therefore, since the silica has silanol groups having high reaction activity on its surface, it can be chemically modified with a desired organic component.

Hereinafter, specific embodiments of the present invention will be described with reference to examples. Needless to say, these are intended to clarify the technical significance of the present invention, and the technical scope of the present invention is not construed as being limited thereto.

In the following examples, the silanol groups, the aspect ratio and the amount of crystalline free silicic acid were determined by the above methods.

[0082]

【Example】

[Example 1] In an aqueous solution of sodium silicate, titanium dioxide (TTO-55A manufactured by Ishihara Sangyo Co., Ltd .: particle size 0.03 to 0.0)
5 μm 2), and an aqueous sodium silicate solution (SiO ₂ 1) in which titanium dioxide fine particles are dispersed using a wet bead mill.
6.86 wt%, TiO ₂ 9.09 wt%, Na ₂ O
6.42% by weight).

In a 1000 cm ³ autoclave (electrically heated type, with anchor type stirring blades), silica sol (composition SiO ₂ 8.5% by weight, Na ₂ O 0.73% by weight,
_{iO 2 / Na 2 O = 12.0mol} / mol) 228
g, 80 g of an aqueous sodium silicate solution prepared by dispersing titanium dioxide prepared as described above, and 492 g of water, 0.1 g of seed crystals were added, and a hydrothermal treatment was performed at 200 ° C. for 14 hours while stirring at 10 rpm. The starting material silica sol is JI
It was obtained by diluting S3 water glass with water and electrodialyzing. The average particle diameter of colloidal silica in the water glass was 3 nm when measured with a laser scattering particle size analyzer manufactured by Otsuka Electronics Co., Ltd. It was below.

The hydrothermally treated product was filtered, washed with water, subjected to a dispersion treatment with an ultrasonic homogenizer, and after filtration, the attached water was replaced with acetone, and dried at 180 ° C. for 2 hours to obtain 25.5 g of fine powder. The chemical composition of the fine _powder, SiO 2 71.5 wt%, was TiO ₂ 28.5% by weight.

The resulting fine powder was identified for its product phase by powder X-ray diffraction spectrum. As a result, 2θ = 4.9.
Silicas X and 2 characterized by peaks at ゜ and 26.0 ゜
It was found to be composed of rutile titanium dioxide characterized by a peak at θ = 27.5 °. The oil absorption of the fine powder was measured by (JIS K5101) and found to be 72.
ml / 100 g, which was found to be moderate.

When the shape of the product was observed with a scanning electron microscope, the shape of the primary particles was a scale plate shape. In addition, almost no titanium dioxide particles were present as a mixture, and most of the particles had an appearance in which the particles were encapsulated in the flaky plate-like particles and composited. The average maximum length of the plate with respect to the thickness was 5 μm and the aspect ratio was 63 with respect to the average thickness of the scale-plate-like primary particles of 0.08 μm.

Further, when the amount of the crystalline form of free silicic acid was measured by X-ray diffraction analysis, it was found to be below the detection limit (less than 2%).

The IR spectrum is 3600 to
One to 3700cm ^-1, one absorption band is present in the 3400~3500cm ^-1.

Next, 1.12 g of petrolatum and 0.48 g of liquid paraffin were added to 0.4 g of the flaky plate-like particles, and a paste obtained by well dispersing using a three-roll mill was used. And spread it until the layer thickness became 25 μm, and measured the spectral transmittance using a self-recording spectrophotometer. The transmittance at each wavelength is shown in [Table 1]. 500 nm is a visible light region, a 400 nm and a 320 nm ultraviolet light region. The smaller the transmittance in the ultraviolet light region, the better the ultraviolet shielding effect.

Further, the measurement of photocatalytic activity was as follows.
isopropyl alcohol 25 in a clear glass bottle
and 0.63 g of the flaky plate-like particles (TiO ₂ 0.
18g), and the mixture was tightly stoppered and exposed to direct sunlight for one day in fine weather while stirring with a stirrer. Thereafter, the amount of acetone produced by oxidative decomposition of isopropyl alcohol by the photocatalytic oxidation action was measured by gas chromatography to be 0.007% by volume. Since the amount of acetone produced was extremely small as compared with Comparative Example 1, this indicated that the titanium dioxide in the flaky plate-like particles was encapsulated in the flaky silica substrate and was complexed.

Example 2 Titanium dioxide (372 g) was added to 372 g of water.
TTO-55A manufactured by Ishihara Sangyo Co., Ltd .: Particle size 0.03 ~
4 g of 0.05 μm 2) was added, and a dispersion of titanium dioxide fine particles was prepared using a wet bead mill in the same manner as in Example 1.

In a 1000 cm ³ autoclave (electrically heated, with anchor type stirring blade), silica sol (composition SiO ₂ 8.5% by weight, Na ₂ O 1.25% by weight,
424 g of iO ₂ / Na ₂ O = 7.0 mol / mol) and 376 g of dispersion water of the fine particles of titanium dioxide were added, 0.1 g of a seed crystal was added, and hydrothermal treatment was performed at 200 ° C. for 14 hours while stirring at 10 rpm. went. The starting material silica sol was obtained by diluting JIS No. 3 water glass with water and electrodialyzing it. The average particle size of the colloidal silica contained therein was measured by a laser scattering particle size analyzer manufactured by Otsuka Electronics Co., Ltd. It was 3 nm or less when measured by the apparatus.

The hydrothermally treated product was filtered, washed with water, and then subjected to a dispersion treatment with an ultrasonic homogenizer. After filtration, the adhered water was replaced with acetone and dried in the same manner as in Example 1 to obtain 28.0 g of a fine powder. The chemical composition of the fine _powder, SiO 2 85.8 wt%, was TiO ₂ 14.2% by weight.

The product phase of the obtained fine powder was identified by powder X-ray diffraction spectrum. As in Example 1, silica X and silica X having peaks at 2θ = 4.9 ° and 26.0 ° were used. It was found to be composed of rutile type titanium dioxide characterized by a peak at 2θ = 27.5 °. When the oil absorption of the fine powder was measured in the same manner as in Example 1, it was found to be 116 ml / 100 g, which was an appropriate value.

When the shape of the product was observed with a scanning electron microscope, the shape of the primary particles was a scale plate shape. In addition, almost no titanium dioxide particles were present as a mixture, and most of the particles had an appearance in which the particles were encapsulated in the flaky plate-like particles and composited. The average maximum length of the plate relative to the thickness was 4 μm and the aspect ratio was 67 with respect to the average thickness of the scale-plate-like primary particles of 0.06 μm.

Further, the amount of the crystalline free silicic acid was measured by X-ray diffraction analysis and found to be below the detection limit (less than 2%).

The IR spectrum was the same as in Example 1 in both the position and the number of the absorption bands.

The spectral transmittance was measured in the same manner as in Example 1. The results are shown in [Table 1].

The photocatalytic activity was measured in the same manner as in Example 1 except that the amount of the dry powder added was 1.25 g (containing 0.18 g of TiO ₂ ). Acetone was not detected.

Example 3 Zinc oxide (fine zinc white, manufactured by Honjo Chemical Co., Ltd .: particle size: 0.1 μm) was added to 424 g of water.
g was added, and a dispersion of zinc oxide fine particles was prepared using a wet bead mill in the same manner as in Example 1.

A 1000 cm ³ autoclave (electrically heated, with an anchor-type stirring blade) was charged with silica sol (composition of SiO ₂ 8.5% by weight, Na ₂ O 1.31% by weight,
348 g of iO ₂ / Na ₂ O = 6.7 mol / mol) and 452 g of the dispersion water of the above zinc oxide fine particles were charged, and 0.1 g of a seed crystal was added, and a hydrothermal treatment was performed at 200 ° C. for 14 hours while stirring at 10 rpm. Was. The starting material silica sol was obtained by diluting JIS No. 3 water glass with water and electrodialyzing it. The average particle size of the colloidal silica contained therein was measured by a laser scattering particle size analyzer manufactured by Otsuka Electronics Co., Ltd. It was 3 nm or less when measured by the apparatus.

The hydrothermally treated product was filtered, washed with water, and then subjected to a dispersion treatment with an ultrasonic homogenizer. After filtration, the attached water was replaced with acetone and dried to obtain 27.5 g of a fine powder. The chemical composition of the fine powder was 71.1% by weight of SiO ₂ and 28.9% by weight of ZnO.

The product phase of the obtained fine powder was identified by powder X-ray diffraction spectrum. As in Example 1, silica X and silica X having peaks at 2θ = 4.9 ° and 26.0 ° were used. It was found to be composed of zinc oxide characterized by a peak at 2θ = 36.2 °. The oil absorption of the fine powder was measured in the same manner as in Example 1.
ml / 100 g, which was found to be moderate.

Further, the amount of crystalline free silicic acid was measured by X-ray diffraction analysis and found to be below the detection limit (less than 2%).

The IR spectrum was the same as in Example 1 in both the position and the number of the absorption bands.

The measurement of the spectral transmittance was performed in the same manner as in Example 1. The results are shown in [Table 1].

[0107]

[Table 1]

[Comparative Example 1] Titanium dioxide (Ishihara Sangyo Co., Ltd.)
) TTO-55A: particle size 0.03-0.05 μm)
Using only one, the photocatalytic activity was measured.

Evaluation was performed in the same manner as in Example 1 using 0.18 g of titanium dioxide powder. The amount of acetone in isopropyl alcohol was measured by gas chromatography and found to be 0.117% by volume.

Example 4 The samples of Example 1, Example 2, and Comparative Example 1 were treated with sulfuric acid (65% by weight) and ammonium sulfate (10% by weight) to determine the soluble content of titanium dioxide. Was done. The results are shown in [Table 2].

From these results, it was found that the titanium dioxide in the flaky plate-like particles of the present invention was significantly less soluble than in Comparative Example 1, and the titanium dioxide in the flaky plate-like particles was encapsulated in the flaky silica. It shows that it is complex.

[0112]

[Table 2]

Example 5 Using the titanium dioxide composite scale plate-like particles obtained in Example 2, a foundation as shown in Table 3 below was produced.

[0114]

TABLE 3 Titanium dioxide composite scale plate-like particles of Example 2 20.0% by weight Vaseline 5.0% by weight Liquid paraffin 15.0% by weight Distilled water 57.0% by weight Triethanolamine 3.0% by weight

Comparative Example 2 17.2% by weight of spherical silica gel (particle diameter: 12 μm) and titanium dioxide (particle diameter: 0.03 to 0) were used in place of the titanium dioxide composite scale plate-like particles of the foundation prepared in Example 5. 0.05 μm) A foundation was produced in the same manner as in Example 5 except that 2.8% by weight was used.

Next, based on the foundation of Comparative Example 2, the foundation of Example 5 was 1) hard,
2) extensibility, 3) oiliness, 4) gloss, 5) transparency,
6) Sensory evaluation was made on six items of stickiness.

The foundation of Example 5 was comparable to the standard foundation in three items: 1) hardness, 3) oiliness, and 6) stickiness, but 2) extensibility. The evaluations of 4) gloss and 5) transparency were evaluated as excellent.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI C30B 7/10 C30B 7/10 // A61K 7/035 A61K 7/035 (72) Inventor Eiichi Ono Wakamatsu-ku, Kitakyushu-shi, Fukuoka 13-1 Kitaminato Town Dokai Chemical Industry Co., Ltd.

Claims (15)

[Claims] Claims: 1. A composite particle comprising silica and metal or metal compound fine particles encapsulated therein, wherein the silica has a crystalline free silicic acid value of 1 measured by X-ray diffraction analysis.
Composite particles based on silica, characterized in that they are less than 0%. 2. The composite particle according to claim 1, wherein the primary particle of the composite particle is a composite particle basically having a scale plate shape. 3. The scale plate has a thickness of 0.001 to 1 μm, and the ratio of the longest length of the scale plate to the thickness (aspect ratio).
3. The composite particle according to claim 2, wherein is at least 5. 4. The composite particles according to claim 1, wherein the primary particles of the metal or metal compound fine particles have a size of 0.01 to 0.5 μm or less. 5. The composite particle according to claim 1, wherein the content of the metal or metal compound fine particles in the composite particle is 1 to 50% by weight. 6. The metal or metal compound fine particle has an ultraviolet shielding function.
5. The composite particle according to any one of the above items 5. 7. The composite particles according to claim 6, wherein the fine particles of the metal or metal compound having an ultraviolet shielding function are fine particles selected from the group consisting of titanium dioxide, zinc oxide, cerium oxide and iron oxide. . 8. 0.40 parts by weight of the composite particles are added to 1.12 parts by weight of petrolatum and 0.48 parts by weight of liquid paraffin.
Thickness of paste obtained by dispersing using three rolls 25
Spectral transmittance in μm is 20% at a wavelength of 320 nm
The composite particle according to claim 6, wherein: 9. The method according to claim 1, wherein the metal or metal compound fine particles have a photocatalytic oxidation action.
8. The composite particle according to any one of items 7 to 7. 10. The concentration of acetone produced by oxidative decomposition of isopropyl alcohol after exposure to direct sunlight for one day at room temperature using the composite particles is 0.05% by volume or less. The composite particles according to the above. 11. A cosmetic comprising the composite particles according to any one of claims 1 to 10. 12. The method according to claim 1, wherein a silica sol obtained by dealkalizing an alkali silicate aqueous solution is used as a starting material, and the silica sol is subjected to hydrothermal treatment in a state in which fine particles of a metal or a metal compound are dispersed therein. 1 to 1
0. The method for producing a composite particle according to any one of the above items. 13. A silica / alkali molar ratio (SiO ₂ / Me ₂ O, where Me represents an alkali metal) of a silica sol as a starting material is 3.5 mol / mol to 20 mol.
The method for producing composite particles according to claim 12, wherein the ratio is / mol. 14. A silica sol having a silica particle diameter of 100 n.
14. The method for producing composite particles according to claim 12, wherein m is equal to or less than m. 15. The method for producing composite particles according to claim 12, wherein a seed crystal is added during the hydrothermal treatment.