JP2004051408A - Porous non-conductive ceramic particles having improved fluidity and method for producing the same - Google Patents

Abstract

The present invention provides a porous non-conductive ceramic particle having improved fluidity by preventing aggregation due to charging, and a method for producing the same.
A porous non-conductive ceramic particle having improved fluidity by impregnating a surfactant (particularly a non-ionic surfactant). The sphericity of the porous non-conductive ceramic particles is preferably 0.7 to 1.0, the porosity is 10 to 70%, and the average particle size is preferably 50 to 500 μm. The water content after impregnation with the surfactant is preferably 0.5 to 3% by weight higher than the water content before impregnation. The surfactant to be impregnated is preferably in the form of an aqueous solution having a concentration of 0.05 to 5% by weight.
[Selection diagram] None

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a porous non-conductive ceramic particle having improved fluidity and a method for producing the same, and more particularly, to a porous material having improved fluidity in a simple manner without affecting the properties of the porous non-conductive ceramic particle itself. Non-conductive ceramic particles and a method for producing the same.
[0002]
[Prior art]
Porous ceramics have various properties and functions such as light weight, heat insulation, sound absorption, adsorption, separation function, and selective transmission function, in addition to the inherent heat resistance and chemical resistance properties of ceramics. Therefore, its applications are expanding in various fields.
[0003]
For example, a porous calcium phosphate compound represented by porous hydroxyapatite has excellent biocompatibility and is used as a biomaterial such as an artificial root, a bone reinforcing material, or a dental cement. When porous hydroxyapatite is used as a biomaterial, it is generally used as a sintered body, or as a homogeneous mixture of a binder resin or the like, and may be used as a molded body (for example, JP-A-2000-335962). In each case, the porous hydroxyapatite is used in the form of particles.
[0004]
In addition to hydroxyapatite, there are various types of ceramics that can be used as porous ceramic particles. For example, alumina-based ceramics have (1) uniform pore distribution and (2) good affinity with microorganisms. (3) Recyclable, (4) High mechanical strength, (5) Multifunctional ceramics for water treatment, catalyst carrier, sensor substrate, composite material due to excellent chemical resistance , Bioreactors, microbial carriers, adsorbents, hybrid materials, filter materials and the like. In addition, porous silica is also used as a column packing material for chromatography, in addition to the above-mentioned uses.
[0005]
However, since the porous ceramic particles as described above are generally non-conductive, they are charged as a powder during handling, and the particles tend to aggregate. When the particles are aggregated, there is a possibility that the transportation path of the ceramic particles and the opening of the hopper of the molding machine may be closed. Therefore, it is desired to prevent charging of the ceramic particles so that they can be easily handled.
[0006]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a porous non-conductive ceramic particle having improved fluidity by preventing aggregation due to charging, and a method for producing the same.
[0007]
[Means for Solving the Problems]
In light of the above objects, as a result of intensive studies, the present inventors have found that by impregnating the surface of the pores of the porous non-conductive ceramic particles with a surfactant, the particles no longer agglomerate, thereby improving the fluidity. And found the present invention.
[0008]
That is, the porous non-conductive ceramic particles having improved fluidity of the present invention are characterized by being impregnated with a surfactant.
[0009]
The porous non-conductive ceramic particles having improved fluidity according to the present invention preferably have a sphericity of 0.7 or more, preferably have a porosity of 10 to 70%, and have an average porosity of 50 to 500 μm. It preferably has a particle size.
[0010]
In the porous non-conductive ceramic particles having improved fluidity according to the present invention, the water content after impregnation with the surfactant is preferably higher by 0.5 to 3% by weight than the water content before impregnation.
[0011]
The porous non-conductive ceramic particles of the present invention preferably comprise porous hydroxyapatite.
[0012]
Preferably, the surfactant is a non-ionic surfactant.
[0013]
The method for producing porous non-conductive ceramic particles having improved fluidity according to the present invention is characterized in that the porous non-conductive ceramic particles are impregnated with a surfactant to prevent aggregation of the particles. I do.
[0014]
Preferably, the surfactant is brought into contact with the porous non-conductive ceramic particles in a solution having a concentration of 0.05 to 5% by weight. It is preferable to set the amount of the surfactant impregnated so that the water content after the impregnation of the surfactant is 0.5 to 3% by weight higher than the water content before the impregnation.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
[0016]
[1] Porous non-conductive ceramic particles having improved fluidity (1) Porous non-conductive ceramic particles The porous non-conductive ceramic particles having improved fluidity according to the present invention have a true sphere of 0.7 or more. Preferably, it has a porosity of 10 to 70% and an average particle size of 50 to 500 μm.
[0017]
The sphericity of ceramic particles is closely related to the fluidity of the particles. Therefore, the sphericity is preferably 0.7 or more. Here, the sphericity is determined by a circularity coefficient (4π × area / perimeter ² ). If the sphericity is less than 0.7, sufficient fluidity cannot be obtained even if the porous non-conductive ceramic particles are treated with a surfactant.
[0018]
The porosity of the porous non-conductive ceramic particles to which the present invention can be applied is preferably in the range of 10 to 70%. If the porosity is less than 10%, not only the properties as porous ceramic particles cannot be exhibited, but also the pores cannot be sufficiently supported even if impregnated with a surfactant. On the other hand, when the porosity exceeds 70%, not only the particle strength is excessively reduced, but also it becomes difficult to secure the sphericity. The porosity can be measured by a mercury porosimeter method.
[0019]
The average particle size of the porous non-conductive ceramic particles to which the present invention can be applied is preferably from 50 to 500 μm, and more preferably from 100 to 500 μm. When the average particle size is less than 50 μm, it is easy to atomize during flow. On the other hand, when the average particle size exceeds 500 μm, it becomes difficult to ensure uniformity when press-molding or blending the ceramic particles with the resin. The average particle diameter is a value obtained by averaging particle diameters obtained by a laser diffraction method for 1,000 particles.
[0020]
The porous non-conductive ceramic particles satisfying the above conditions may be made of any ceramics as long as they are non-conductive ceramics. can do.
[0021]
The Ca / P weight ratio of the calcium phosphate-based ceramic is preferably from 1.6 to 1.7. When the weight ratio of Ca / P is less than 1.6, a mixed phase with tricalcium phosphate [Ca ₃ (PO ₄ ) ₂ ] is obtained, and when it is more than 1.7, a mixed phase with calcium oxide (CaO) is formed. Become. A preferred example of the porous calcium phosphate ceramics to which the present invention is applied is porous hydroxyapatite [Ca ₁₀ (PO ₄ ) _6. (OH) ₂ ].
[0022]
The porous non-conductive ceramic particles are preferably secondary particles in which fine primary particles are aggregated. As the secondary particles, those formed by a spray drying granulation method or the like are preferable from the viewpoint that the sphericity, the porosity, and the average particle size are easily controlled.
[0023]
(2) Surfactant The surfactant to be impregnated into the pores of the porous non-conductive ceramic particles may be any of a nonionic surfactant, a cationic surfactant, an anionic surfactant and an amphoteric surfactant. However, a nonionic surfactant is preferable from the viewpoint of antistatic.
[0024]
Nonionic surfactants include polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether (for example, polyoxyethylene octyl phenyl ether), glycerin fatty acid partial ester, sorbitan fatty acid moiety Examples thereof include esters, pentaerythritol fatty acid partial esters, polyoxyethylene sorbitan acid fatty partial esters, polyoxyethylene alkyl ether carboxylate, and fatty acid alkanolamides (for example, N, N-dimethyldodecylamine oxide).
[0025]
Examples of the cationic surfactant include an alkylamine salt and a dialkylamine salt.
[0026]
Examples of the anionic surfactant include dialkyl sulfosuccinate, alkane sulfonate, alkylbenzene sulfonate, alkyl naphthalene sulfonate, polyoxyethylene alkyl sulfophenyl ether salt, alkyl phosphate ester salt, and polyoxyethylene alkyl ether. Examples thereof include a phosphate ester salt, a fatty acid alkyl ester sulfate ester salt, an alkyl sulfate ester salt, a polyoxyethylene alkyl ether sulfate ester salt, and a fatty acid monoglyceride sulfate ester salt.
[0027]
Examples of the amphoteric surfactant include N, N, N-trialkyl-N-sulfoalkylene ammonium betaine.
[0028]
(3) Impregnation of Surfactant The amount of the surfactant to be impregnated into the porous non-conductive ceramic particles is such that the water content after the surfactant is impregnated is 0.5 to 3% by weight higher than the water content before the impregnation. It is preferable to set as follows. The amount of surfactant impregnated necessary to obtain such a water content is generally 0.0025 to 0.3 parts by weight, preferably 0.005 to 0.3 parts by weight, per 100 parts by weight of the porous non-conductive ceramic particles. 0.05 parts by weight. If the amount of the surfactant is less than the lower limit, the effect of improving the fluidity by impregnation is insufficient, and if the amount exceeds the upper limit, the effect corresponding thereto cannot be improved.
[0029]
[2] Fluidization Treatment Method The method of impregnating the porous non-conductive ceramic particles with the surfactant is not limited, and a method of dipping a surfactant solution, a method of spraying, and the like can be used. Note that "impregnation" means that the surfactant is retained not only on the surface but also in the pores.
[0030]
The surfactant solution for impregnating the ceramic particles is preferably at a concentration of 0.05 to 5% by weight. If the concentration is less than 0.05% by weight, a sufficient amount of surfactant cannot be impregnated, and if the concentration exceeds 5% by weight, further improvement in fluidity cannot be obtained. The surfactant solution is preferably an aqueous solution from the viewpoint of easy processing.
[0031]
The porous non-conductive ceramic particles impregnated with the surfactant solution are heated to an appropriate temperature and dried sufficiently. In order to secure sufficient fluidity, it is preferable that the water content of the porous non-conductive ceramic particles carrying the surfactant is 10% or less.
[0032]
【Example】
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
[0033]
Example 1
As the porous non-conductive ceramic particles, porous hydroxyapatite particles having a sphericity of 0.8, a porosity of 50%, an average particle size of 110 μm, a maximum particle size of 300 μm by classification, and a water content (loss on drying) of 4% by weight are used. used. A 0.1% by weight aqueous solution of polyethylene glycol mono-p-iso-octylphenyl ether (trade name “Triton X-100”) was sprayed on the particles as a nonionic surfactant. The ceramic particles were heated at 200 ° C. for 2 hours before and after spraying the surfactant, and the loss on drying in each case was measured. Since the respective weight loss was 4% by weight and 5.1% by weight, the increase in water content by spraying was 1.1% by weight. The porous hydroxyapatite particles impregnated with the surfactant were smooth.
[0034]
In order to evaluate the fluidity of the porous hydroxyapatite particles impregnated with the surfactant, a glass cylinder 1 having an inner diameter of 20 mm shown in FIG. 1 was used. The glass cylinder 1 includes an upper portion 1a, a lower portion 1b, and a reduced diameter portion 1c connecting the both, and an orifice 2 having an inner diameter D of 1.0 mm is provided at the center of the reduced diameter portion 1c.
[0035]
The porous hydroxyapatite particles 3 impregnated with a surfactant were put into the upper part 1a of the glass cylinder 1 and dropped naturally by gravity into the lower part 1b via the orifice 2. When the fluidity of the particles 3 was evaluated in this state, clogging of the particles 3 in the orifice 2 did not occur even after 3 minutes.
[0036]
Comparative Example 1
A 0.1% by weight aqueous solution of Triton X-100 as a nonionic surfactant was sprayed on dense hydroxyapatite particles (sphericity: 0.8, average particle size: 110 μm, maximum particle size by classification: 300 μm). After spraying, the dense hydroxyapatite particles were left in the air and completely dried. When the fluidity of the dense hydroxyapatite particles coated with the surfactant was evaluated using the glass cylinder 1 shown in FIG. 1, the orifice 2 was clogged in 5 seconds.
[0037]
Comparative Example 2
A glass cylinder shown in FIG. 1 without applying a nonionic surfactant to the same dense hydroxyapatite particles as Comparative Example 1 (sphericity: 0.8, average particle diameter: 110 μm, maximum particle diameter by classification: 300 μm) When the fluidity was evaluated in 1, orifice 2 was clogged in 5 seconds.
[0038]
【The invention's effect】
As described above, by impregnating the surfactant according to the present invention, the porous non-conductive ceramic particles do not become charged during the flow, and thus can maintain good flowability. The porous non-conductive ceramic particles subjected to the treatment of the present invention are suitable for transportation by a pipe or the like.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing a glass cylinder for evaluating the fluidity of porous non-conductive ceramic particles.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Glass cylinder 1a ... Upper part 1b ... Lower part 1c ... Reduced diameter part 2 ... Orifice

Claims (10)

Porous non-conductive ceramic particles having improved fluidity, characterized by being impregnated with a surfactant. The porous non-conductive ceramic particles with improved fluidity according to claim 1, wherein the sphericity is 0.7 or more. The porous non-conductive ceramic particles having improved fluidity according to claim 1 or 2, wherein the porosity is 10 to 70%. . The porous non-conductive ceramic particles having improved fluidity according to any one of claims 1 to 3, wherein the average particle size is 50 to 500 µm. Ceramic particles. The porous non-conductive ceramic particles having improved fluidity according to any one of claims 1 to 4, wherein the water content after impregnation with the surfactant is 0.5 to 3% by weight more than the water content before impregnation. Porous non-conductive ceramic particles having improved fluidity, characterized in that they are abundant. A porous non-conductive ceramic particle having improved fluidity according to any one of claims 1 to 5, wherein the ceramic particle is made of porous hydroxyapatite. Conductive ceramic particles. The porous non-conductive ceramic particle having improved fluidity according to any one of claims 1 to 6, wherein the surfactant is a nonionic surfactant, and the fluidity is improved. Porous non-conductive ceramic particles. The method for producing porous non-conductive ceramic particles having improved fluidity according to any one of claims 1 to 7, wherein the porous non-conductive ceramic particles are impregnated with a surfactant to form the particles. A method of preventing aggregation of the particles. 9. The method for producing porous non-conductive ceramic particles having improved fluidity according to claim 8, wherein the surfactant is in the form of a solution having a concentration of 0.05 to 5% by weight. A method comprising contacting with particles. The method for producing porous non-conductive ceramic particles having improved fluidity according to claim 8 or 9, wherein the water content after impregnation of the surfactant is 0.5 to 3% by weight more than the water content before impregnation. A method characterized in that the amount of the surfactant impregnated is set so as to increase.

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