JP2008093629A - Manufacturing method of composite particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a composite particle by laminating a particle layer, wherein particles smaller than a nuclear particle and having a uniform particle size are regularly arranged, on the surface of the nuclear particle to cover the same without unevenly deforming the surface of the nuclear particle or grinding a plate-shaped nuclear particle. <P>SOLUTION: The manufacturing method of the composite particle wherein particles B are regularly arranged on a part or the whole surface of a particle A includes a process for covering the surface of a particle A with an average particle size of 1-1,000 μm with particles B of which the average particle size is below 1/5 or below that of the particle A and the coefficient of variation is 50% or below using 0.001-10 g/m<SP>2</SP>of an aqueous liquid per the unit area of the particle A as a joining medium. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing composite particles. More specifically, a composite that can be suitably used for cosmetics, paints, inks, and resin compositions with controlled water repellency, oil repellency, optical properties, UV protection, infrared protection, touch, safety, activity, etc. The present invention relates to a method for producing particles.

  A method for producing composite particles of powder and fine particles using an organic compound as a medium using a supercritical fluid or a subcritical fluid is known (see Patent Document 1).

  However, in the composite particles obtained by this method, the fine particles cover the powder surface with a single layer in a uniformly dispersed state, and there is no regularity in the arrangement of the fine particles.

  Further, composite particles in which the surface of spherical polyethylene particles is coated with regularly arranged silica particles are known (see Non-Patent Document 1).

  However, this composite particle is produced by impact treatment in a high-speed air stream using a hybridizer, and a part of the silica particle is embedded in the surface of the spherical polyethylene particle that is the core particle. The surface is deformed in an uneven shape. Moreover, since a strong mechanical action works at the time of manufacture, it is difficult to apply to fragile plate-like particles such as mica.

  In addition, a method is known in which plate-like powder and organic spherical powder are dry-mixed with a mixer and combined by a mechanochemical method (see Patent Document 2).

However, the composite particles obtained by this method have no regularity in the arrangement of the fine particles.
JP 2004-82089 A Colloids and Surface A: Physicochemical and Engineering Aspects, 82 (1994), H. Honda, M. Kimura, F. Honda, T. Matsuno, M. Koishi, p. 117 Japanese Patent Laid-Open No. 9-12430

  The problem of the present invention is that the surface of the core particle is smaller than the core particle and has a uniform particle size without causing irregular deformation of the surface of the core particle or pulverization of the plate-like core particle. It is an object of the present invention to provide a method for producing composite particles covered with a layer of particles arranged in an ordered manner.

In the present invention, particles B having an average particle size of 1 to 1000 μm on the surface of particles A having an average particle size of 1/5 or less of the particle A and a coefficient of variation of 50% or less are 0.001 to The present invention relates to a method for producing composite particles in which particles B are regularly arranged on a part of or the entire surface of particles A, including a step of coating with 10 g / m ^{2 of} an aqueous liquid as a bonding medium.

  According to the present invention, particles having a uniform particle size smaller than the core particles are regularly formed on the surface of the core particles without deforming the surface of the core particles into irregularities or pulverizing the plate-like core particles. Composite particles coated with an ordered particle layer can be produced.

In the method for producing composite particles of the present invention, 0.001 to 10 g / m ^{2 of} an aqueous liquid per unit surface area of particle A is used as a bonding medium for particle A (core particle) and particle B (coated particle). In this method, the particle B is coated on a part or the entire surface. In the present invention, by utilizing the liquid cross-linking force of the liquid, it becomes possible to make a composite under a relatively gentle mixing operation condition. Therefore, deformation of the surface of the particle A and pulverization of the particle A are suppressed, and the particle A A particle layer in which particles B smaller than particles A and having a uniform particle diameter are regularly arranged can be formed on the surface. In the present invention, the state in which the particles B are regularly arranged is a state in which the particles B are two-dimensionally uniformly dispersed on the surface of the particle A, and 4 to 7 particles centering on one particle B, Most ideally, a state in which a basic array in which six particles B are arranged adjacent to each other is continuously repeated is preferable.

  Examples of the particles A include inorganic particles such as talc, mica, sericite, kaolin, zeolite, titanium-coated mica, barium sulfate, zirconium oxide, glass beads, glass flakes, and silica; styrene resin, acrylic resin, polyolefin, nylon, Examples include silicone resins, fluororesins, polyesters, polyamides, and other thermoplastic resins, and epoxy polymers, particles of organic polymer compounds such as phenolic resins, and the like. Among these, they have a smooth surface. From the viewpoint, glass flakes are preferable. These can be used alone or in admixture of two or more.

  As the particles A, particles having a smooth surface are preferable from the viewpoint of preventing the regular arrangement of the particles B from being hindered. The particles having a smooth surface mean particles that are judged as a smooth surface as a whole even if they have some unevenness. Further, the shape of the particles A may be spherical or plate-like.

  The average particle diameter of the particles A is not particularly limited, but is 1 to 1000 μm, preferably 1 to 200 μm, more preferably 5 to 100 μm from the viewpoint of allowing the particles B to exist on the surface of the particles A. When the particle A is a plate-like particle, the longest diameter on one plane is the particle diameter of the particle, and the average particle diameter is calculated by a laser diffraction scattering method (area standard).

  Examples of the particles B include inorganic particles such as silica, zinc oxide, titanium oxide, zirconium oxide, barium sulfate, yellow iron oxide, black iron oxide, and bengara; styrene resin, acrylic resin, polyolefin, nylon, silicone resin, fluorine resin And particles of organic polymer compounds such as thermoplastic resins such as polyester and polyamide, and thermosetting resins such as epoxy resin and phenol resin. These can be used alone or in admixture of two or more.

  From the viewpoint of preventing the regular arrangement of the particles B, the particles B are preferably spherical particles having a uniform particle size. From this viewpoint, the coefficient of variation (CV value) of the particles B is preferably 50% or less, and more preferably 40% or less. Here, the CV value is obtained by dividing the standard deviation of the particle diameter by the average particle diameter.

  Further, from the viewpoint of improving the uniformity of the coating of the particles A by the particles B, the particles B are preferably hydrophobic or water repellent. When the particle B itself is neither hydrophobic nor water-repellent, the surface of the particle B is preferably subjected to a hydrophobic treatment or a water-repellent treatment with a fluorine compound or the like.

  The average particle diameter of the particles B is 1/5 or less, preferably 1/10 or less, more preferably 1/20 or less, from the viewpoint of being present on the surface of the particles A. The average particle diameter of the particles B is preferably 0.1 to 200 μm, more preferably 0.1 to 20 μm, and further preferably 0.1 to 5 μm from the viewpoint of allowing the particle B to exist on the surface of the particle A and improving the feel of the particles. . The average particle diameter of the particle B is a number average particle diameter calculated from an observation image obtained by a scanning electron microscope (SEM). The coefficient of variation is calculated from the particle size distribution on a volume basis measured by the laser diffraction scattering method.

  The amount of the particles B is appropriately selected in consideration of the specific gravity and particle size of the particles A and B to be used.

  In the present invention, an aqueous liquid is used as the joining medium. In the present invention, the aqueous liquid may be water or an aqueous solution containing an inorganic salt and / or an organic compound.

  Examples of the inorganic salt include water-soluble inorganic compounds such as sodium chloride, potassium chloride, sodium hydroxide, sodium sulfate, and ammonium sulfate. In addition, a trace amount of an inorganic compound having very low solubility may be dissolved.

  Examples of the organic compound include hydrophilic organic solvents such as methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, and dimethylformamide, and water-soluble organic compounds such as sodium acetate, sucrose, and polyvinyl alcohol. An organic compound having very low solubility may be dissolved in a trace amount.

  When the content of the inorganic salt or the organic compound in the aqueous solution and both are used in combination, the total amount is preferably 50% by weight or less, and more preferably 10% by weight or less.

The amount of aqueous liquid per unit surface area of the particles A, a 0.001 to 10 g / m ^2, preferably ^{0.001~1g / m 2, 0.001~0.5g / m} 2 is more preferable.

  It is preferable that at least one of the particle A and the particle B is coated in advance with the aqueous liquid serving as a bonding medium between the particle A and the particle B before being subjected to the mixing operation. From the viewpoint of enhancing the ratio, it is more preferable that the particles A are coated in advance by a method such as mixing of the particles A and an aqueous liquid.

  The mixing operation in the present invention is not a mixing operation that applies a large stress such as a hybridizer (manufactured by Nara Machinery Co., Ltd.) or the like, but is relatively gentle due to a stress that does not cause particle breakage during the composite treatment. Mixing operations that can be performed under conditions are preferred. In addition, a dry mixing operation in which the powder can be operated as it is is preferable to a wet operation in which the powder is slurried using a large amount of liquid solvent. Specifically, mixing operations such as mixing with a stirring blade in the mixing tank, spraying, coating, and compounding by friction with a rotating disk, etc. are preferable. From the viewpoint of uniformity of compounding and ease of operation, high-speed flow Dry mixing using a mold mixer is more preferred. Examples of the high-speed fluid mixer suitably used in the present invention include a super mixer (manufactured by Kawata Co., Ltd.), a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), a high speed mixer (manufactured by Fukae Kogyo Co., Ltd.) and the like. It is done.

  From the viewpoint of improving the uniformity and productivity of the coating with the particles B, the peripheral speed (blade diameter × π × rotational speed) when using a high-speed fluid mixer is preferably 0.1 to 50 m / s, and 0.3 to 30 m / s. Is more preferable.

  Further, from the viewpoint of improving the coating uniformity with the particles B, the mixing time when using a high-speed fluid mixer is preferably 0.5 minutes or more, more preferably 1 minute or more, and further preferably 5 minutes or more. The upper limit of the mixing time is not particularly limited, but is preferably 10 hours or less and more preferably 5 hours or less from the viewpoint of productivity.

In the composite particles obtained by the present invention, the particles B covering the particles A may be in a single-layer structure or a three-dimensionally laminated structure. In addition, when forming the laminated structure, it is preferable that the said joining medium exists also in the interlayer formed with the particle | grains B. FIG. In the present specification, the composite particle in which the coating layer by the particle B is a multilayer is described as a multilayer composite particle, and the composite particle in which the coating layer by the particle B is a single layer with respect to the multilayer composite particle May be described as single-layer composite particles. Further, when the particle B is a laminate, the particle B forming the n-th layer when viewed from the surface of the particle A is the particle forming the (n + 1) -th layer formed on the layer composed of the particles B _n and the particles B _n. B may be referred to as particle B _{n + 1} .

In the case of producing a laminated composite particle in which the surface of the particle A is coated in a state where the particle B is not a single layer but a multilayer (laminated), the particle A (single layer composite) coated with the particle B (particle B ₁ ) The particles B are laminated by coating the surface of the single-layer composite particles with the particles B (particles B ₂ ) that form the second layer using an aqueous liquid as a bonding medium. Can do.

In the composite particles obtained by the present invention, the coverage by the particles B on the surface of the particles A is preferably 50% or more, more preferably 70% or more, and further preferably 90% or more. When the particle layer composed of the particles B is a single layer, the coverage by the particles B on the surface of the particles A is preferably 50% or more, more preferably 70% or more, and further preferably 90% or more. The coverage with particles B is given by the formula (A):
Coverage (%) = (b / a) × 100 (A)
(Wherein, a is the number (particles / cm ² ) in which particles B are packed in a single layer in the particle A unit area, and b is the number of particles B per particle A unit area in the composite particles (particles / cm ² ). ² ))
Is calculated by

Further, when the particle layer composed of the particles B is a multilayer, the particles B forming the m-th layer when viewed from the surface of the particles A are the (m + 1) layers formed on the layer composed of the particles B _m and the particles B _m. When the particles B to form the eye to as particle B _{m + 1,} coverage by the particles B _{m + 1} at the surface of the composite particles coated with particles B _m is preferably at least 50%, more 70% or more Preferably, 90% or more is more preferable. The coverage by the particles B _{m + 1} is expressed by the formula (B):
Coverage (%) = (b _{m + 1} / a _m ) × 100 (B)
(Wherein, a _m is the number (pieces / cm ² where the particles B _{m + 1} in a unit area of the composite particles coated with particles B _m is close-packed in a single layer), b m _{+ 1} is composited shows the number of particles B _{m + 1} per unit area of the composite particles coated with particles B _m in the particle (number / cm ²⁾⁾
Is calculated by

  The obtained composite particles may be appropriately subjected to operations such as crushing and crushing. Further, the particle B may be immobilized on the particle A by an operation such as sintering, plasticizing, coating, etc. according to the substance constituting the obtained composite particle.

  The average particle size of the composite particles obtained by the present invention is preferably from 1 to 1000 μm, more preferably from 1 to 200 μm, from the viewpoint of handling as particles. The average particle diameter of the composite particles is also measured in the same manner as the average particle diameter of the particles A.

  Particles A and B each have desired properties such as water repellency, oil repellency, optical properties, UV protection, infrared protection, touch, safety, and activity control depending on the application of the composite particles. It is preferable. The composite particles obtained by the present invention can be applied to various fields depending on their properties.

Example 1
High-speed fluidized mixer Super mixer (trade name: Piccolo SMP-2, manufactured by Kawata Co., Ltd., internal volume: 300 mL, blade diameter: 73 mm), plate-like titanium oxide-coated glass flakes [average particle size: 80 μm, product Name: Metashine 1080RC-S1, Nippon Sheet Glass Co., Ltd. 30.0 g, monodispersed spherical silica particles [average particle size: 0.31 μm, coefficient of variation: 20.2%, product name: Seahoster KE-P30, Nippon Shokubai Co., Ltd. 5.00 g was charged, the rotation speed of the super mixer was adjusted to 3000 r / min (circumferential speed 11.5 m / s), and the mixture was mixed for 5 minutes.

Next, 1.80 g of ion-exchanged water (0.082 g / m ² per unit surface area of the plate-like titanium oxide-coated glass flakes) is added as a joining medium, and the rotation speed of the super mixer is set to 3000 r / min (circumferential speed 11.5 m / s). Combined and mixed for 15 minutes to obtain composite particles.

  Scanning electron micrographs of the resulting composite particles are shown in FIGS. 1 and 2 (magnification: 5000 times).

  From the photograph shown in FIG. 1, monodispersed spherical silica particles cover a part of the surface of the plate-like titanium oxide-coated glass flakes, and the silica particles are surrounded by six particles around one particle. It can be seen that a regular ordered structure is formed. However, on the other hand, it can be seen from the photograph shown in FIG. 2 that the monodispersed spherical silica particles are aggregated in another part.

Example 2
High-speed fluidized mixer Super mixer (trade name: Piccolo SMP-2, manufactured by Kawata Co., Ltd., internal volume: 300 mL, blade diameter: 73 mm), plate-like titanium oxide-coated glass flakes [average particle size: 80 μm, product Name: Metashine 1080RC-S1, Nippon Sheet Glass Co., Ltd.] 30.0 g and 1.80 g of ion-exchanged water (0.082 g / m ² per unit surface area of plate-like titanium oxide coated glass flakes) as the joining medium The rotational speed was adjusted to 3000 r / min (circumferential speed 11.5 m / s), and the mixture was mixed for 5 minutes to obtain surface ion-exchanged water-treated plate-like titanium oxide-coated glass flakes.

  Next, 5.00 g of monodispersed spherical silica particles (average particle size: 0.31 μm, coefficient of variation: 20.2%, trade name: Seahoster KE-P30, Nippon Shokubai Co., Ltd.) were charged.

  After charging, the rotation speed of the super mixer was adjusted to 3000 r / min (circumferential speed 11.5 m / s) and mixed for 15 minutes to obtain composite particles.

  A scanning electron micrograph of the resulting composite particles is shown in FIG. 3 (magnification: 5000 times).

  From the photograph shown in FIG. 3, monolithic spherical silica particles cover almost the entire surface of the plate-like titanium oxide-coated glass flakes, although the number of laminated particles is somewhat large, and the silica particles are centered on one particle. It can be seen that a regular array structure surrounded by six particles is formed.

Example 3
Monodispersed spherical silica particles surface-treated with a fluorine compound instead of monodispersed spherical silica particles [average particle size: 0.32 μm, coefficient of variation: 35.7%, trade name: PF-5 ALH05 SS-300, silica particles: catalyst Kasei Kogyo Co., Ltd., Surface treatment: Daito Kasei Co., Ltd., Surface treatment agent: Perfluoroalkyl phosphate diethanolamine salt (0.0055 g / m ² )] 5.03 g] was used in the same manner as in Example 1. As a result, composite particles were obtained.

  A scanning electron micrograph of the obtained composite particles is shown in FIG. 4 (magnification: 5000 times).

  From the photograph shown in FIG. 4, although there is some coating unevenness, monodisperse spherical silica particles cover almost the entire surface of the plate-like titanium oxide-coated glass flakes, and the silica particles are centered on one particle and the periphery thereof. It can be seen that a regular array structure surrounded by six particles is formed.

Example 4
Monodispersed spherical silica particles surface-treated with a fluorine compound instead of monodispersed spherical silica particles [average particle size: 0.32 μm, coefficient of variation: 35.7%, trade name: PF-5 ALH05 SS-300, silica particles: catalyst Kasei Kogyo Co., Ltd., Surface treatment: Daito Kasei Co., Ltd., Surface treatment agent: Perfluoroalkyl phosphate diethanolamine salt (0.0055 g / m ² )] 5.03 g] was used in the same manner as in Example 2. As a result, composite particles were obtained.

  A scanning electron micrograph of the obtained composite particles is shown in FIG. 5 (magnification: 5000 times).

  From the photograph shown in FIG. 5, the entire surface of the plate-like titanium oxide-coated glass flakes is covered with surface fluorinated monodispersed spherical silica particles, and the silica particles are surrounded by six particles around one particle. It can be seen that a regular ordered structure is formed.

Comparative Example 1
High-speed fluidized mixer Super mixer (trade name: Piccolo SMP-2, manufactured by Kawata Co., Ltd., internal volume: 300 mL, blade diameter: 73 mm), plate-like titanium oxide-coated glass flakes [average particle size: 80 μm, product Name: Metashine 1080RC-S1, Nippon Sheet Glass Co., Ltd. 30.0 g, surface fluorinated monodispersed spherical silica particles [average particle size: 0.32 μm, coefficient of variation: 35.7%, product name: PF-5 ALH05 SS-300 Silica particles: Catalyst Kasei Kogyo Co., Ltd., Surface treatment: Daito Kasei Co., Ltd., Surface treatment agent: Perfluoroalkyl phosphate diethanolamine salt (0.0055 g / m ² )] 8.38 g.

  After charging, the rotation speed of the super mixer was adjusted to 3000 r / min (circumferential speed 11.5 m / s) and mixed for 15 minutes to obtain composite particles.

  A scanning electron micrograph of the obtained composite particles is shown in FIG. 6 (magnification: 5000 times).

  From the results shown in FIG. 6, it can be seen that the surface-fluorinated monodispersed spherical silica particles are hardly attached to the surface of the titanium oxide-coated glass flakes and are not combined.

  An outline of Examples 1 to 4 and Comparative Example 1 is shown in Table 1.

  The composite particles obtained by the present invention are suitable for cosmetics, paints, inks and resin compositions with controlled water repellency, oil repellency, optical properties, UV protection, infrared protection, touch, safety, activity, etc. It can be used for.

2 is a scanning electron micrograph (magnification: 5000 times) showing the particle structure of the composite particles obtained in Example 1. FIG. 2 is a scanning electron micrograph (magnification: 5000 times) showing the particle structure of the composite particles obtained in Example 1. FIG. 4 is a scanning electron micrograph (magnification: 5000 times) showing the particle structure of the composite particles obtained in Example 2. FIG. 4 is a scanning electron micrograph (magnification: 5000 times) showing the particle structure of the composite particles obtained in Example 3. FIG. 4 is a scanning electron micrograph (magnification: 5000 times) showing the particle structure of the composite particles obtained in Example 4. FIG. 3 is a scanning electron micrograph (magnification: 5000 times) showing the particle structure of the composite particles obtained in Comparative Example 1. FIG.

Claims (7)

On the surface of the particle A having an average particle diameter of 1 to 1000 μm, particles B having an average particle diameter of 1/5 or less of the particle A and a coefficient of variation of 50% or less are applied to the surface of the particle A by 0.001 to 10 g / m ^2. A method for producing composite particles in which particles B are regularly arranged on a part of or the entire surface of particles A, which comprises a step of coating with the aqueous liquid as a bonding medium.   The method for producing composite particles according to claim 1, wherein the surface of the particle A is coated with the particle B by dry mixing with a high-speed fluid mixer using an aqueous liquid as a bonding medium.   The method for producing composite particles according to claim 1 or 2, wherein the particles A are plate-like or spherical particles.   The method for producing composite particles according to claim 1, wherein the particles B are spherical particles having an average particle diameter of 0.1 to 200 μm.   The composite particle according to any one of claims 1 to 4, wherein the surface of the particle A is coated with an aqueous liquid in advance and then the particle B is added to coat the particle B with the aqueous liquid as a medium. Production method.   The method for producing composite particles according to any one of claims 1 to 5, wherein the particles B are hydrophobic or water-repellent.   The method for producing composite particles according to any one of claims 1 to 6, wherein the particles B are particles whose surfaces have been subjected to a hydrophobic treatment or a water repellent treatment.