JPH0423576B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a novel granule in which non-lipophilic fine particles or lipophilic fine particles are encapsulated using wax, and a method for producing the same. Specifically, the present invention relates to a granule and a method for producing the same, in which an unexpected effect is achieved by modifying and effectively combining a submerged curing method and a submerged granulation method as microencapsulation methods. The granules and the method for producing the same according to the present invention are useful in the industrial and pharmaceutical fields related to conventional microcapsules, and are particularly useful in producing dense and strong ceramics when the raw material fine particles are ceramic raw materials. Conventional techniques and problems The main conventional microencapsulation methods for particulate materials include coacervation method, in-liquid curing method,
Interfacial polymerization methods, submerged granulation methods, and the like are known. Conventional manufacturing methods each have their own characteristics, but all of them tend to form adhesion areas between granulated particles, and the shape of the granulated bodies tends to be non-uniform. It was hot. Particularly in the case of ceramic materials, if there are adhering parts between granules, abnormal grain growth occurs during shaping and sintering, which tends to deteriorate the strength. The main object of the present invention is to substantially eliminate the above-mentioned problems, and to provide a granule that is essentially spherical and has substantially no adhesion between the granule particles, and a method for producing the same. . Means for Solving the Problems According to the present invention, a lipophilic microparticle, a water-immiscible solvent and an encapsulating effective amount of wax are provided.
The process is characterized by forming a dispersion system in which the wax is heated and dissolved in the solvent; adding and mixing a heated aqueous surfactant solution to the system; and then rapidly cooling; A method for producing granules encapsulated in wax and having a surfactant adhered to the surface of the encapsulated wax is provided. In the above, when the fine particles to be granulated are non-oleophilic fine particles, the above-mentioned granules can be advantageously obtained by treating with a lipophilic coupling agent to make the fine particles lipophilic. In this way, a large number of lipophilic fine particles are encapsulated in wax to form an essentially spherical granule structure, and a surfactant is attached to the surface of the granule to form a granule. Granules comprising the fine particles and an effective amount of encapsulated wax are provided, characterized by a structure that prevents interbody adhesion. Specific Embodiments of the Invention (1) Fine Particles to be Granulated The fine particles to be granulated are powders with a particle size of about 10 microns or less, and usually about 5 microns or less. Non-oleophilic particles are generally hydrophilic, and typically include alumina, zirconia, mullite,
Examples include metal compound powders such as titania, barium titanate, ferrite, carbide compounds (silicon carbide, etc.), titanium compounds (silicon titanide, etc.), metal powders, other metal oxides, and mixtures thereof. Examples of lipophilic fine particles include fine particles of industrial organic compounds and organic drugs. (2) Size of the granules The resulting encapsulated granules are essentially spherical, with a particle size of about 5 to 500 microns, usually about 10 to 250 microns, and typically about 20 microns. ~
It is about 150 microns. (3) Coupling agent A lipophilic coupling agent for treating non-oleophilic fine particles is an organic compound that substantially chemically bonds to the surface of the fine particles to form an organic surface portion. Typically, aluminum-based coupling agents (e.g. acetalkoxyaluminum diisopropylate, trade name AL-M series); titanate-based coupling agents [e.g. tetraoctyl bis(ditridecylphosphite) titanate, trade name KR-series]; and silane coupling agents (e.g. vinyltrimethoxysilane, trade name
KBM series) etc. are exemplified. The amount used is generally about 0.2 to 2% based on the fine particles. (4) Wax Wax is an organic substance that is solid at room temperature and dissolves or melts when heated;
Animal-based, vegetable-based, mineral and petroleum-based natural waxes; hydrocarbon-based, modified waxes, hydrogenated oil-based waxes,
Synthetic waxes based on fatty acids and their derivatives;
and waxes containing these are exemplified. The wax is generally used after being heated and dissolved in a water-immiscible solvent (for example, a lipophilic solvent such as kerosene). Generally, approximately
It is used in an amount of about 0.1 to 3%, usually about 0.2 to 1%. (5) Surfactant The surfactant is a non-oil miscible solution such as a dilute aqueous solution (concentration is about 0.1 to 1% by weight, usually about 0.5%).
used as. The type of surfactant is not particularly limited as long as it does not adversely affect the mixed system. As a preferred example, a nonionic surfactant having an HLB of about 4 is advantageously used. Usually, alkali or alkaline earth metal salts of higher fatty acids (lauric acid, stearic acid, etc.) or higher unsaturated fatty acids (oleic acid, linoleic acid, linolenic acid, etc.) are preferably used. The use of surfactants increases the wetting properties of the wax component, increases granulation, and prevents adhesion between granules. (6) Water-immiscible solvent The water-immiscible solvent for forming the dispersion system of the fine particles to be granulated and wax is not particularly limited, but lipophilic solvents such as kerosene (kerosene) can usually be used advantageously. . (7) Examples of amounts of each component The amounts of each of the above components can be changed depending on the equipment, process, etc. The table below shows examples of formulations used in the case of a granule dispersion system consisting of fine alumina particles, beeswax, kerosene, surfactant, and water. The same applies when other components are used.

[Table] (8) Manufacturing example Manufacturing process examples for each component amount in (7) above are summarized below. Γ Chemicals used: Aluminum coupling agent AL-M, manufactured by Ajinomoto Co.; titanate coupling agent KR46B, or silane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd.
KBM1003 Manufactured by Wako Pure Chemical Industries, Ltd. Sodium oleate Manufactured by Wako Pure Chemical Industries, Ltd. Beeswax Manufactured by Kao Corporation Nonion OP-0-30 () Coupling agent treatment 600 g of alumina in a pot mill, 500 g of distilled water
ml and 6.0 ml of coupling agent and mix for about 1 hour. The slurry is removed and dried at 120°C for 12 to 24 hours (until the solvent disappears). If it has solidified after drying, crush it in an automatic mortar. () Granulation process Weigh and mix 50 ml of kerosene and 12 to 120 grams of treated alumina powder for component (7) above. Add beeswax and heat (90℃) according to the amount of ingredients in (7) above. …Liquid A Take 2.5g of sodium oleate, dissolve it in 500ml of distilled water, and heat and hold it (90ml).
℃). ...Liquid B Take 80ml of Liquid B in a separate beaker, add 10ml of Liquid A, and stir vigorously. ...Liquid C Rapidly cool down Liquid C to 5°C while stirring.
...Liquid D Measure the liquid D on a slide glass and observe the granules with an optical microscope to confirm spherical granules. If a dispersion system is not required, deliquid treatment is performed. Actions and Effects The granules according to the present invention utilize the difference in surface tension between the oil component and water to effectively granulate fine particles in water. Non-oleophilic particles such as alumina are
Lipophilic particles can be made by treatment with a coupling agent. This allows the powder to be stably dispersed in a lipophilic system such as kerosene or beeswax. Lipophilic granules such as kerosene and beeswax are immiscible with water, so if left untreated, lipophilic granules will stick to each other, so in order to improve the granules' affinity with water, sodium oleate, etc. Add surfactant. This effect allows lipophilic systems such as alumina, kerosene, and beeswax to stably exist in water. FIG. 1 shows a schematic diagram of spherical granules stably dispersed in water. This illustrates the operation and effect of the present invention.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram illustrating a spherical granule stably dispersed in water according to the present invention.

Claims (1)

[Scope of Claims] 1. A dispersion system consisting of lipophilic fine particles, a water-immiscible solvent, and an effective amount of wax for encapsulation, in which the wax is heated and dissolved in the solvent: a heated aqueous surfactant solution. is added to the system and mixed; and then rapidly cooled: A granule in which a large number of the fine particles are encapsulated in the wax and a surfactant is attached to the surface of the encapsulated wax. manufacturing method. 2. The lipophilic fine particles are lipophilic fine particles obtained by treating non-lipophilic fine particles with a lipophilic coupling agent.
The manufacturing method according to claim 1. 3. The manufacturing method according to claim 2, wherein the non-oleophilic fine particles are inorganic fine particles. 4. It has an essentially spherical granule structure in which a large number of lipophilic fine particles are encapsulated in wax,
and characterized by a structure in which a surfactant is attached to the surface of the granules to prevent adhesion between the granules.
A granule comprising the fine particles and an effective amount of encapsulated wax. 5. The lipophilic fine particles are lipophilic fine particles obtained by treating non-lipophilic fine particles with a lipophilic coupling agent.
Granules according to claim 4. 6. The granule according to claim 5, wherein the non-oleophilic fine particles are inorganic fine particles.