JPS59230633A - Preparation of coated particulate substance - Google Patents

Abstract

PURPOSE:To obtain a good coated product generating no flocculation, by a method wherein a liquid or pasty substance, a heat meltable substance and a thermoplastic substance are added to a powder and coated with said powder by a powder fluidized bed method to form a powder wall microcapsule while a core particulate substance is added to perform stirring. CONSTITUTION:One or more of a liquid or pasty substance (e.g., animal and vegetable oils and fats with a low m.p., various aqueous solutions), a thermoplastic substance and a heat meltable substance (e.g., a substance melted or softened at 30 deg.C or more, oils and fats, fatty acid, fatty acid ester, higher fatty alcohol or a wax substance such as polyhydric alcohol) are added to a powder such as starch to be coated with said powder by a powder fluidized bed method to form a powder wall microcapsule. A substance coming to a core is added to said capsule under stirring in a mixer to homogenously adhere or stick the powder wall microcapsule or broken substances thereof to the surface of the core substance. By this method, good coating can be performed in a primary particle state without generating flocculation of the substance to be coated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a coated granular material, and to a method for obtaining a granular material with improved hygroscopicity, solubility, etc.

Generally, the method for coating powders and granules is to dissolve the coating material in water or an organic solvent, and then spray the solution while fluidizing the powder or granules with air or rolling them on a transfer plate. There are two methods: first, then drying and coating, or heating and melting a heat-soluble substance such as oil or fat or higher fatty acid, spraying it onto fluidized or rolling powder, and then cooling and coating. be. In the former coating method, moisture and organic solvents tend to penetrate into the coated material, impairing storage stability, and require a lot of time and equipment to dry the moisture and remove the solvent. In the latter coating method, the equipment is relatively inexpensive, but if the particle size of the material to be coated is small, agglomeration occurs and it is difficult to coat the surface uniformly, making it difficult to obtain a good coated product. Furthermore, when the material to be coated is a powder or fine granules, in the conventional coating method, the coating material coagulates with the binder and granules, making it difficult to coat the material as primary particles. In addition, since agglomeration and granulation occur, it has the disadvantage that it is difficult to achieve a uniform and good coating due to the large number of voids.

As a result of intensive studies to eliminate the drawbacks of conventional coating methods, the present inventors added one or more types of liquid or pasty substances, heat-soluble substances, and thermoplastic substances to powder and applied a coating method using a powder bed method. After coating to form powder-walled microcapsules, a core powder substance is added to the powder-walled microcapsules and stirred in a mixer to coat the powder-walled microcapsules on the surface of the core substance. Alternatively, the inventors discovered that by uniformly adhering or adhering the broken particles of the powder-walled microcapsules, the substance to be coated does not agglomerate and a good coating can be achieved with the primary particles intact, leading to the completion of the present invention. Ta.

First, as the first step of the present invention, a liquid or paste substance,
Microcapsules are prepared by a powder bed method using one or more of a thermosoluble substance and a thermoplastic substance as a core substance and a powder as a powder wall. The powder for the powder wall used in the present invention is not particularly limited as long as it is fine and can be encapsulated by a powder bed method. Examples include saccharides such as starch, dextrin, and glucose, celluloses such as crystalline cellulose and cellulose derivatives, proteins such as gelatin, casein, and soybean protein, silica, talc, and others.

The thermoplastic substance used in the present invention may be any thermosoluble substance as long as it melts or softens at 30°C or higher, such as waxy substances such as fats and oils, fatty acids, fatty acid esters, aliphatic higher alcohols, and polyhydric alcohols. There is. Examples of fats and oils include animal fats such as lard, head, and tallow, and hydrogenated vegetable oils such as 9-gum oil, coconut oil, and cottonseed oil. Waxy substances include carnauba wax, wood wax, rice bran wax, and beeswax. Examples of fatty acids include higher fatty acids such as stearic acid and palmitic acid, and examples of fatty acid esters include glycerin esters of higher fatty acids such as glycerin monostearate. Examples of higher alcohols include lauryl alcohol and cetyl alcohol, and examples of polyhydric alcohols include mannitol, sorbitol, maltitol, and the like. As the liquid or paste-like substance, low-melting point animal and vegetable oils and fats and various aqueous solutions can be used. Microencapsulation using the powder method involves dropping droplets from above the powder layer, while the liquid method wets the material with the powder. It is done by taking advantage of this.

Regarding the powder method, see "Microcapsule JI: 1970, pp. 125-126 (written by Asashi Kondo)" published by Nikkan Kogyo Shimbun.
] is described as follows, and such a method can be applied.

When making capsules using the powder bed method, there are various forms as shown below, but which of the four materials - the core material, the wall material, the solvent, and the inert powder - should be used as the powder bed, and which should be used as the powder bed. It depends on whether it is solvent-based or not. Among these, inert powder is not necessarily required, but the first three are absolutely necessary as materials for encapsulation.

(1) The wall material is powdered and the core material is dissolved or dispersed in a solvent to form falling drops.

(2) A mixture of both the core material and wall material is used as a powder bed, and a solvent is dripped into it. (3) A mixture of the core material, wall material, and inert powder is used as a powder bed, and a solvent is dripped into it.

(4 Inert powder is used as a powder bed, and the core substance dispersed in the wall material solution is dropped.

(5) Make the wall material powder into a powder bed, and drop the core material dispersed in the wall material solution.

(6) Using inert powder as a powder bed, the hot molten core material is dropped.

It can be divided as above. Inert powder is mainly an inorganic powder that does not dissolve in solvents, and although it does not form a strict membrane by itself, it is embedded in the wall membrane and acts as a filler, helping to strengthen the capsule membrane and removing solvents. It acts to absorb and speed up the apparent drying of the dropped droplets.

As the wall membrane material, cellulose acetate phthalate, aluminum aspirin, gelatin, casein, dextrin, glucose, etc. are used. However, most other materials can be used as long as they are solvent-based and can be made into fine powder. When you are concerned about the shape of the resulting capsule, if you want a spherical one, the wetting and dissolution rate of the wall material powder in the solvent, the viscosity of the dripping liquid, etc. are issues, so consider the combination empirically. I need to decide.

As the inert powder, silica, talc, sodium aluminum silicate, decomposition, etc. are used.

Particularly when encapsulating only the inert powder bed as a powder, the particle size, stirring, etc. affect the encapsulation.

Next, in the second step, the powder or granules of the core substance are added to the powder-walled microcapsules and stirred well in a mixer that applies a strong shearing force, so that the core powder or granules are coated on the surface of the core powder or granules. A powder wall microcapsule or a destroyed product of the microcapsule is attached. Powder-walled microcapsules are destroyed by the shear force of the high-speed stirring blades, thermofusible substances or thermoplastic substances are melted by frictional heat, and liquid or paste-like substances are directly melted onto the surface of the material to be coated. Attach and spread. At this time, the powder wall film of the powder wall microcapsule is also attached at the same time, and a new powder wall film is formed on the surface of the substance to be coated.

The coating powder obtained in this way is powder 1.
It is coated on one primary particle.

If the coated primary particles are further subjected to a conventional method such as fluidized bed coating, an even better coated product can be obtained.

The present invention can be used as a method for preventing moisture, controlling solubility, deodorizing, and preventing caking of foods, pharmaceuticals, agricultural chemicals, feeds, and their additives, and for purposes such as adding odor, flavor, coloring, and shaping. . In addition, sweeteners, flavoring agents, coloring agents, etc. can also be added depending on these purposes.

The feature of the present invention is that the coating material can be uniformly coated even if the core material of the obtained granular material is powder, whereas in the conventional method, coating is not possible when the core material is powder. However, according to the method of the present invention, 1
Even if the powder is about 00μ, it can be coated as a primary particle, which is excellent. Furthermore, the coating device is a stirring device, etc., which is relatively simple compared to conventional coating devices, and can be carried out in a short period of time, making it a low-cost method. Furthermore, since the method of the present invention does not use any solvent or water, it does not require a drying process.
It does not require any equipment or time, and can be used even for substances that are unstable to solvents and water.

Example 1 30g of cornstarch with an average particle size of 70μ and 15g of edible fat (hardened beef tallow melting point 40°C) were mixed in a centrifugal rotating Mechano Mill (MM).
-10 type) for 30 minutes at a rotational speed of 1100 Orp to obtain powder-walled oil and fat microcapsules. Mixing was carried out by the so-called powder bed method by dropping droplets onto a rotating powder bed.

Next, 100 g of methionine crystals and the above microcapsules 4511 were placed in the above Mechano Mill at a rotation speed of 50 Orpm.
The mixture was stirred and mixed for about 30 minutes. At this time, the υ microcapsules were destroyed by the shearing force of the blades, and oil and fat and corn starch were uniformly adhered to the surface of the methionine crystals.

In conventional fluid coating and rolling coating methods, it is impossible to complete the coating process with the primary particles remaining, especially when the core material is in the form of powder. The particles were coated as they were. The coated methionine had almost no odor peculiar to methionine and was improved to be easily added to foods.

Example 2 Rice starch 15.9 with an average particle size of 10μ and Ajinomoto Co., Inc. stationary fat [Hightone 30J15,9] were mixed in the same manner as in Example 1 using a centrifugal rotating Mechano Mill at a rotation speed of 11,000 rpm.
Mixed for a minute to obtain powder-walled microcapsules of fat and oil.

Next, in a fluidized granulator, 50 q6 powdered soy sauce and 50 ml of sodium glutamate were prepared into granules having a particle size of about 1 cylinder φ. 50 g of these granules and 20 g of the above powder wall microcapsules.
9 was stirred and mixed in a centrifugal rotating Mechanomill at a rotation speed of 60 Orpm for about 30 minutes. As a result, rice starch,
A homogeneous coating of fat and oil was created. These granules had significantly improved moisture absorption and caking properties compared to uncoated products, and were excellent in handleability.

Example 3 20g of crystalline cellulose with an average particle size of about 10μ and carnauba wax 209 were heated at a rotation speed of 1 using a centrifugal rotating Mechanomill.
Mix at 1000 rpm for 30 minutes to obtain wax powder wall microcapsules. Mix and stir 80 I potato starch with a particle size of 100 to 150 μm and 20 g of methionine powder in the centrifugal rotating Mechanomill for 30 minutes at 1100 rpm. Methionine powder was uniformly adhered to the surface of the starch particles. Next, 40 g of the wax microcapsules were placed in the same centrifugal rotating Mechano Mill, and the rotation speed was 60 Orpm.
Mixing and stirring were performed for 0 minutes. As a result, a coating of wax and crystalline cellulose was formed around the starch to which methionine was attached.

When the coated methionine granules were dissolved in hot water at 38° C., it was observed that about 40 ions were eluted in one hour, and methionine granules with a controlled dissolution time were obtained.

Claims (1)

[Claims] One or more of liquid or pasty substances, thermoplastic substances, and thermosoluble substances are added to the powder and coated by a powder method to form powder-walled microcapsules, and then the powder-walled microcapsules are coated with a core. The powder-walled microcapsules or the broken material of the powder-walled microcapsules are uniformly adhered or adhered to the surface of the core material by adding a substance and stirring in a mixer. A method for producing powdery and granular materials.