JP6980569B2 - Coated granular fertilizer, manufacturing method of coated granular fertilizer, compound fertilizer and cultivation method - Google Patents

Description

The present invention relates to a coated granular fertilizer, a method for producing a coated granular fertilizer, a compound fertilizer and a cultivation method.

The coated granular fertilizer whose surface is coated with a coating material such as resin has excellent elution controllability of fertilizer components, and is therefore recognized to have effects such as achievement of labor saving in agricultural work and reduction of environmental load. Cultivation techniques using such coated granular fertilizers are becoming widespread.

In recent years, the demand for quality and cost has been further increased. In particular, there are extremely high demands for maintaining and improving quality and cost balance, which are conflicting properties. In order to reduce the cost, studies are being made to reduce the proportion of the coating material to make it thinner (lower the composition), and to increase the proportion of the fertilizer component relatively to increase the composition.

In general, the larger the proportion of the coated granular fertilizer, the easier it is to control the quality such as elution control and maintenance of the film strength. In order to show excellent elution controllability after fertilization, it is necessary to eliminate film defects (pinholes, etc.) that occur during fertilization, and for that purpose, a certain amount of film is required.

Resins are mentioned as a general coating material used for coated granular fertilizer, and various fillers are used as needed. As the resins, an olefin polymer having a small moisture permeability is effective for controlling the elution of fertilizer, and includes a film containing polyethylene (see, for example, Patent Document 1) and a resin having a durometer D hardness in the range of 54 to 71. A coating film (see, for example, Patent Document 2) and the like are disclosed.

Mineral powder, starch, or the like is used as the filler. For example, a method for coating a fertilizer coated with a film in which powder is uniformly dispersed in a resin film is mentioned, and a method for reducing costs without impairing the elution function is described. (See, for example, Patent Document 3). Further, there is a coated fertilizer completely coated with a thermoplastic resin and a water-insoluble or water-insoluble inorganic powder, and in particular, it describes quality improvement by being able to control the influence of the elution rate by temperature (see, for example, Patent Document 4). .. Further, with the aim of stabilizing the quality, a coated biologically active granule with little quality variation is described (see, for example, Patent Document 5).

Special Publication No. 54-3104 Japanese Unexamined Patent Publication No. 2002-161002 Special Publication No. 60-102 Japanese Unexamined Patent Publication No. 54-97260 Japanese Unexamined Patent Publication No. 2002-68880

From the above, if the ratio of the coating material is easily reduced, the elution period may be shortened and the quality may be deteriorated due to defects in the coating, and the development of a more effective method is an extremely important issue.
It was known that the filler was used as an active ingredient of the coating film, but each filler thinned the coating film of the coated granular fertilizer and could not be produced with practical productivity. Further improvement of technology is required to make the film thinner with the filler, and the conventional knowledge alone is not sufficient.

An object of the present invention is to find a coating material capable of controlling product quality, particularly elution of fertilizer components, despite being capable of thinning, and coating the coating material with a granular fertilizer to obtain a coated granular fertilizer. It is an object of the present invention to provide a method for producing a granular fertilizer, a compound fertilizer containing the coated granular fertilizer, and a method for cultivating a plant.

The present inventors have diligently studied to solve the above-mentioned problems. As a result, it was found that the above-mentioned problem can be solved by the coated granular fertilizer in which the surface of the granular fertilizer is coated with the coating material containing the resin and high-purity talc, and the present invention has been completed.

There are a wide variety of talc types (composition, particle size, etc.), and they have been used according to their intended use. In particular, high-purity products tend to be white and are suitable for paper. Further, high-purity products with few impurities are suitable for pharmaceuticals and cosmetics. Since high-purity products are expensive, their uses are limited to pharmaceuticals, cosmetics, paper, and the like.

A coated granular fertilizer whose surface is coated with a coating material containing a resin and high-purity talc can improve the coating strength and can be thinned, and can be produced with an elution period similar to that of a conventional coated granular fertilizer. It has not been known so far that it is possible to reduce the cost of the coating material due to the thin film, and the ratio of the active ingredient can be increased, which is surprising to those skilled in the art. This is because talc used for agriculture is important to balance with the effect due to cost constraints, and high-purity products are usually not used. Therefore, those skilled in the art usually do not consider the inclusion of high-purity talc in the coating material as in the present invention.

The present invention comprises the following.
(1)
It has a granular fertilizer containing one or more fertilizer components and a film covering the surface of the granular fertilizer.
The coating is formed from a coating material containing resin and high-purity talc.
The high purity talc in 100% by mass, containing 90 to 95 wt% of MgO and SiO ₂ in total, and including Al ₂ O ₃ 1.5 mass% or less, coated granular fertilizers.
(2)
The coated granular fertilizer according to (1) above, which contains 2 to 15% by mass of a coating in 100% by mass of the coated granular fertilizer.
(3)
The coated granular fertilizer according to (1) or (2) above, which contains 10 to 80% by mass of a thermoplastic resin and 20 to 90% by mass of the high-purity talc in 100% by mass of the coating material.
(4)
The coated granular fertilizer according to any one of (1) to (3) above, wherein the coating material contains one or more selected from a surfactant, a polysaccharide and a derivative of the polysaccharide.
(5)
The coated granular fertilizer according to any one of (1) to (4) above, wherein the median diameter of the high-purity talc is in the range of 6 to 30 μm.
(6)
The coated granular fertilizer according to any one of (1) to (5) above, wherein the high-purity talc has a whiteness of 85 or more.
(7)
The coated granular fertilizer according to any one of (1) to (6) above, which contains 0.5% by mass or less of water in 100% by mass of high-purity talc.
(8)
Any one of (1) to (7) above, wherein the period until the elution rate of the fertilizer component reaches 80% by mass when the coated granular fertilizer is immersed in water at 25 ° C. is 10 to 500 (days). Coated granular fertilizer as described in the section.
(9)
It is a coated granular fertilizer whose elution pattern shows a timed elution type.
The period until the elution rate of the fertilizer component reaches 10% by mass is d1 (day).
When the period until the elution rate of the fertilizer component exceeds 10% by mass and reaches 80% by mass is d2 (day),
The coated granular fertilizer according to any one of (1) to (8) above, wherein d1 / d2 is 0.1 or more and d1 is in the range of 5 to 150 (days).
(10)
A compound fertilizer obtained by mixing the coated granular fertilizer according to any one of (1) to (9) above with the uncoated granular fertilizer.
(11)
Using a covering device having a fluidized bed or a jet layer, after removing the fluid gas containing the solvent discharged from the device with a dust remover, the solvent is recovered by a condenser and / or activated charcoal, and the gas separated by the condenser. A method for producing a coated granular fertilizer, which comprises the following steps (A) to (D), wherein the recovered solvent and the heating gas are circulated and reused by heating with a heater.
Step (A): In the solvent containing one or more selected from toluene, tetrachlorethylene and trichlorethylene.
Resin and 100 mass%, contains 90 to 95 wt% of MgO and SiO ₂ in total, and dissolved or suspended not by coating a coating material comprising a high purity talc containing Al ₂ O ₃ more than 1.5 wt% The process of preparing the liquid;
Step (B): A step of spraying the coating liquid on the granular fertilizer under a flowing gas stream in the coating device and evaporating and drying the solvent in the coating liquid to form a film on the surface of the granular fertilizer;
Step (C): By degassing and removing the solvent contained in the granular fertilizer having the film formed by the step (B) by ventilation, the concentration thereof is 500 ppm or less with respect to the granular fertilizer having the film formed. And step (D): a step of recovering the solvent from the solvent-containing gas after the degassing treatment by ventilation in the step (C) using a condenser and / or activated charcoal.
(12)
A method for cultivating a plant using the coated granular fertilizer according to any one of (1) to (9) or the compound fertilizer according to (10).

According to the present invention, the coating film coated on the granular fertilizer can be thinned. The coated granular fertilizer of the present invention can contain a larger amount of fertilizer components by thinning the coating. The coated granular fertilizer of the present invention has excellent elution controllability of fertilizer components in spite of having a thin film. In particular, the strength of the coating of the coated granular fertilizer can be ensured, and the elution controllability is excellent even during the production of compound fertilizers and mechanical fertilization. Further, in the present invention, by thinning the coating film of the coated granular fertilizer, it is possible to provide the coated granular fertilizer having excellent elution controllability at low cost.
According to the production method of the present invention, the film coated on the granular fertilizer can be thinned, and a coated granular fertilizer having excellent elution controllability of fertilizer components can be produced even though the film is thin.

The compound fertilizer of the present invention makes it possible to supply the optimum granular fertilizer according to the target crop, and the cultivation method of the present invention does not adversely affect the crop, and the work efficiency and the utilization efficiency of the granular fertilizer Is a method that can significantly improve.

FIG. 1 is an example of an apparatus for producing a coated granular fertilizer of the present invention.

Hereinafter, the coated granular fertilizer of the present invention will be described in detail.

[Coated granular fertilizer]
The coated granular fertilizer of the present invention has a granular fertilizer containing one or more fertilizer components and a coating film covering the surface of the granular fertilizer, and the coating film is formed from a coating material containing resin and high-purity talc. the high purity talc in 100% by mass, containing 90 to 95 wt% of MgO and SiO ₂ in total, and including Al ₂ O ₃ more than 1.5 wt%, a coated granular fertilizer. The coated granular fertilizer of the present invention is excellent in elution controllability while achieving thinning of the coating film by coating the entire outer surface of the granular fertilizer with the coating material.

In the coated granular fertilizer of the present invention, a plurality of coating layers may be formed by undercoating the inside of a coating made of a coating material.
The coating of the coated granular fertilizer of the present invention may further contain another coating layer as long as the effect of the present invention is not impaired. For example, a film containing fertilizer components such as trace elements, fertilizer enhancer, pesticide component, etc. on the outermost layer, a film with mechanical resistance, a film for suppressing floating under flooded conditions such as paddy fields, etc. It is possible to form a layer such as a film that controls the decomposability of the entire film.

<Coating material>
The coating material of the present invention contains a resin and high-purity talc. The coating film of the coated granular fertilizer of the present invention is formed from the coating material and is coated on the surface of the granular fertilizer.

<High-purity talc>
High purity talc used in the present invention, the talc commonly used is distinguished by containing a large amount of MgO and SiO _2, a high purity talc in 100 wt%, usually 90-95 of MgO and SiO ₂ in total It contains% by mass, preferably 92 to 95% by mass. Further, in 100% by mass of high-purity talc, the impurity Al ₂ O ₃ is usually contained in an amount of 1.5% by mass or less, preferably 1% by mass or less. _{Al 2} O ₃ is usually contained in an amount of 0.1% by mass or more, preferably 0.2% by mass or more in 100% by mass of high-purity talc.
An example of commercially available talc corresponding to this definition is Crown Talc PP (manufactured by Matsumura Sangyo Co., Ltd.).
The talc may be surface treated (eg, silanized) to ensure good affinity with the polymer.

The content of high-purity talc in the coating material is preferably 20 to 90% by mass, more preferably 30 to 80% by mass, based on 100% by mass of the coating material. When the content of high-purity talc is in the above range, the elution controllability is sufficient, and the coverage can be lowered without increasing the proportion of the resin in the coating material.

In addition to the above, whiteness is another index of talc purity. The whiteness of the high-purity talc of the present invention (measurement method according to JIS P8148) is usually 85 or more, 89 or more, and particularly preferably 90 or more in a dry state. The whiteness of high-purity talc is usually 99 or less, preferably 98 or less. Although the mechanism is unknown, when the whiteness is below the above range, the elution of the fertilizer component may be considerably rapid, and the elution control may be difficult when the film is thinned.

The median diameter D50 (measured by laser diffraction / scattering method) of the high-purity talc of the present invention is usually in the range of 6 to 30 μm, preferably 8 to 20 μm. Among them, high-purity talc having a particle frequency of less than 5 μm of 30% or less and a particle frequency of more than 50 μm of 1% or less is preferable. When the frequency of particles having a median diameter of less than 5 μm exceeds 30% and the frequency of particles having a median diameter of more than 50 μm exceeds 1%, the elution of fertilizer components may be accelerated.

The high-purity talc of the present invention contains, in 100% by mass, water content measured by a weight loss rate at 105 ° C., usually 0.5% by mass or less, preferably 0.4% by mass or less. Further, the high-purity talc of the present invention usually contains 0.01% by mass or more, preferably 0.05% by mass or more of water measured by the weight loss rate at 105 ° C. in 100% by mass. If the weight loss rate of water at 105 ° C. exceeds 0.5% by mass, the elution function of the coated granular fertilizer may be impaired. In particular, foaming due to moisture may occur during coating, which may shorten the elution period. Talc generally contains water that is easily desorbed on the particle surface, and the amount of water contained in talc is affected by humidity and the like.

The physical property value of the talc of the present invention can be measured by a known measuring method. For example, the median diameter D50 is a laser diffraction type particle size distribution measuring device, the whiteness is the Hunter method, and the moisture content is measured by an infrared moisture meter or the like.

<Resin>
The resin of the coating material of the present invention is not particularly limited, and may be either a thermoplastic resin or a thermosetting resin. It is preferable to use a thermoplastic resin as the resin. As the thermoplastic resin, one type may be used alone, or two or more types may be used. Specifically, an olefin-based polymer, a vinylidene chloride-based polymer, a diene-based polymer, waxes, polyester, and a petroleum resin are used. , Natural resin, oil and fat and its modified product, urethane resin and the like.

Examples of the olefin polymer include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-carbon monoxide copolymer, ethylene-hexene copolymer, ethylene-butadiene copolymer, polybutene, and ethylene-butene copolymer. Combined, propylene-butene copolymer, ethylene-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide ternary copolymer, ethylene-acrylic acid ester copolymer (eg ethylene-) (Ethyl acrylate copolymer) and ethylene-methacrylic acid ester copolymers can be mentioned.

Examples of the vinylidene chloride-based polymer include a vinylidene chloride-vinyl chloride copolymer and the like.

Examples of the diene-based polymer include a butadiene polymer, an isoprene polymer, a chloroprene polymer, a butadiene-styrene copolymer, an EPDM polymer, and a styrene-isoprene copolymer.

Examples of waxes include beeswax, wood wax and paraffin.

Examples of the polyester include aliphatic polyesters such as polylactic acid and polycaprolactone, and aromatic polyesters such as polyethylene terephthalate.

The petroleum resin is manufactured from a petroleum distillate, and known ones can be applied. For example, aromatic hydrocarbon resins, aliphatic hydrocarbon resins and the like can be mentioned.

Examples of the natural resin include natural rubber, rosin-based resin, terpene-based resin and the like.

Examples of fats and oils and modified products thereof include animal fats and oils and vegetable fats and oils, and examples thereof include cured products such as hardened castor oil, solid fatty acids and metal salts.

Examples of other thermoplastic resins include polystyrene and the like.

Among the above thermoplastic resins, it is preferable to use an olefin polymer. Specifically, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-carbon monoxide copolymer, ethylene-hexene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, ethylene-vinyl acetate More preferably, it is one or more selected from a copolymer, an ethylene-ethyl acrylate copolymer, and a propylene-butene copolymer.

The content of the thermoplastic resin in the coating material is preferably 10 to 80% by mass, more preferably 20 to 80% by mass, based on 100% by mass of the coating material.

The thermosetting resin used in the present invention includes phenol resin, furan resin, xylene-formaldehyde resin, ketone-formaldehyde resin, amino resin, alkyd resin, unsaturated polyester, epoxy resin, silicon resin, urethane resin, drying oil and the like. Can be mentioned. Of these, urethane resin, epoxy resin or alkyd resin are preferable.

The thermoplastic resin or the thermosetting resin may be used alone or may be contained in the coating material in a mixed state as long as the effects of the present invention are not impaired.

In addition to the resin and high-purity talc, other components such as inorganic and organic fillers (excluding the high-purity talc) are contained in the coating material as long as the effects of the present invention are not impaired. You may. For example, examples of the filler include plate-like fillers such as mica and hydrotalcite, calcium carbonate, silica, clay, various ore crushed products, sulfur and the like. In addition, examples of other components other than the filler include organic substances such as surfactants, polysaccharides and derivatives thereof. Examples of the surfactant include polyethylene glycol, polypropylene glycol, water-soluble substances such as polyalkylene glycol obtained by copolymerization of ethylene glycol and propylene glycol, polyvinyl alcohol, and ethers such as polyethylene glycol-alkyl ether and polyethylene glycol-branched alkyl ether. Ester type nonionic surfactants such as polyethylene glycol-alkyl ester, polyethylene glycol-branched alkyl ester, cationic surfactants, anionic surfactants, amphoteric ion surfactants and Examples thereof include a mixture thereof.

Examples of the polysaccharide or its derivative include cellulose, agar, starch, chitin and its derivative, and chitosan and its derivative, and among these, starch is a preferable material at a low price. As the starch, those derived from corn, tapioca, wheat, potato, rice and sweet potato can be used. Further, as these starches, modified starch such as processed pregelatinized starch may be used. Further, silicone-treated starch or the like having an improved dispersibility and fluidity by treating the starch surface with a silicone resin or the like can also be used. These surfactants, polysaccharides or derivatives thereof may be used alone or in combination of two or more.

The particle size of the filler is preferably 100 μm or less, more preferably 1 to 50 μm. When the particle size is in the above range, problems such as the particle size being too large and the film being peeled off during film formation or the film material solution being clogged in the spray nozzle or the like are unlikely to occur. Even if the particle size of the filler is larger than the thickness of the coating film and a part of the filler protrudes from the surface of the coating film, the intended purpose is achieved as long as the filler is partially incorporated into the coating film and adhered. The particle size may be measured by using a known method such as the laser diffraction type particle size distribution measuring device.

When the coating material contains the above filler or the like, the proportion thereof is not particularly limited, but is preferably 0.1 to 50% by mass, more preferably 1 to 40% by mass, based on 100% by mass of the coating material.

When the coating material contains other components other than the filler such as the above-mentioned surfactant, polysaccharide and its derivative, the ratio is not particularly limited, but is 0.01 to 100% by mass of the coating material. 30% by mass is preferable, and 0.1 to 25% by mass is more preferable.

In addition, various organometallic compounds may be used as the coating material for the purpose of decomposing the resin in the coating. Examples of the organometallic compound that can be used include organometallic complexes and organoacid metal salts. Of these, an iron complex or iron carboxylate is preferable because the photodegradability can be easily adjusted. For example, iron complexes include iron acetylacetonate, iron acetonylacetonate, iron dialkyldithiocarbamate, dithiophosphate, xanthate, benzthiazole and the like. Examples of iron carboxylate include iron compounds such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, behenic acid, oleic acid, linoleic acid, and linoleic acid. These may be added alone or in combination of two or more. The content of the organometallic compound in the coating material is preferably 0.0001 to 1% by mass, more preferably 0.001 to 0.5% by mass. When the content is in the above range, the film is less likely to disintegrate or decompose during storage of the product, and the desired effect can be easily obtained at the time of application.

<Granular fertilizer>
In the coated granular fertilizer of the present invention, the granular fertilizer that can be used as a core material usually contains one or more kinds of nitrogen, phosphoric acid, and Kari as fertilizer components, and specifically, nitrogenous fertilizer and phosphoric acid. In addition to quality fertilizers and potassium fertilizers, fertilizers containing trace elements such as calcium, magnesium, sulfur, iron, manganese and boron, which are essential plant elements, and silicon, can be mentioned as needed. Further, a fertilizer containing a nitrate formation inhibitor, a pesticide component, or the like may be used. Among these, nitrogenous fertilizers containing ammonia sulfate, urea, ammonia nitrate, etc., which have high water solubility and easily flow out into the environment, fertilizers containing potassium sulfate, potassium chloride, etc., and chemicals containing urea, ammoniacal nitrogen, nitrate nitrogen, etc. Fertilizer and the like are preferable, and urea, which has a low unit price per fertilizer component, is more preferable.

The form of the granular fertilizer may be granular, and is more preferably close to a spherical shape from the viewpoint of stably controlling the release rate. The average particle size of the granular fertilizer is 1.0 to 10.0 mm, preferably 1.0 to 5.0 mm. The particle size of the granular fertilizer is not particularly limited, but is usually 1.0 to 10.0 mm, preferably 1.0 to 5.0 mm. By using a sieve, any particle size range can be selected within the above range.

As described above, the granular fertilizer used in the present invention may contain one or more fertilizer components such as nitrogen, phosphoric acid, and potassium, but components other than the above may be used as long as the effects of the present invention are not impaired. It may contain a carrier such as clay, kaolin, talc, bentonite, calcium carbonate, or a binder such as polyvinyl alcohol, sodium carboxymethyl cellulose, and starches. Further, if necessary, it may contain a surfactant such as polyoxyethylene nonylphenyl ether, waste sugar honey, animal oil, vegetable oil, hydrogenated oil, fatty acid, fatty acid metal salt, paraffin, wax, glycerin and the like. No.

As the granulation method of the granular fertilizer, an extrusion granulation method, a fluidized bed granulation method, a rolling granulation method, a compression granulation method, a coated granulation method, an adsorption granulation method and the like can be used. In the present invention, any of these granulation methods may be used.

The shape of the granular fertilizer is not particularly limited, but a spherical shape is preferable in order to exhibit excellent elution behavior in spite of the thin film. Specifically, the circularity coefficient obtained by the following formula is preferably a spherical shape of 0.7 or more, more preferably 0.75 or more, still more preferably 0.8 or more. The maximum value of the circularity coefficient is 1, and the closer the particle is to 1, the closer the particle is to a perfect circle, and the smaller the circularity coefficient is as the particle shape collapses from the perfect circle.
Circularity coefficient = {(4π × projected area of particle) / (length of outline of particle projection) ² }

The coating film of the coated granular fertilizer of the present invention is coated on the surface of the granular fertilizer which is the core material, and the covering ratio varies depending on the shape and size of the core material, but is preferably 2 to 15% by mass. , 2.5 to 12% by mass, more preferably 3 to 10% by mass. Here, the coverage is defined as the ratio of the coating to 100% by mass of the coated granular fertilizer, and is calculated by the following formula.
Coverage [mass%] = (mass of coating material / mass of coated granular fertilizer) x 100
When the coverage is in the above range, the elution controllability is sufficient and a thin film can be obtained. On the other hand, if the coverage is too small, it is necessary to reduce the productivity and cover it carefully, and if the coverage is large, the time required for coating is required, which increases the cost.

The average particle size of the coated granular fertilizer is 1.0 to 10.0 mm, preferably 1.0 to 5.0 mm. The particle size of the coated granular fertilizer is not particularly limited, but is usually 1.0 to 10.0 mm, preferably 1.0 to 5.0 mm.
The form of the coated granular fertilizer is not particularly limited, but is preferably granular and more preferably close to spherical from the viewpoint of stably controlling the release rate.

The elution control function of the coated granular fertilizer of the present invention is indicated by the elution rate of the fertilizer component when the coated granular fertilizer is immersed in water (the ratio of the fertilizer component eluted in water to the total amount of fertilizer component contained in the coated granular fertilizer). be able to. Fertilizers are generally water-soluble, and the longer the elution period, the higher the technical difficulty in producing coated granular fertilizers. Further, if there is a film defect, many fertilizer components are eluted at the same time as fertilizer application, which is insufficient as an elution control function. The coated granular fertilizer of the present invention is required to have a period of 10 to 500 (days) until the elution rate of the fertilizer component reaches 80% by mass when the coated granular fertilizer is immersed in water at 25 ° C. , (A) Requirements) are preferred.

The elution rate of the coated granular fertilizer can be measured, for example, by allowing the coated granular fertilizer to stand in water at 25 ° C. and quantitatively analyzing the fertilizer components eluted in the water over time. The method for determining the elution rate of fertilizer components is, for example, a method proposed by the National Institute for Agro-Environmental Sciences, Ministry of Agriculture, Forestry and Fisheries (“Fertilizer Analysis Method” P.155-156, by the National Institute for Agro-Environmental Sciences, Ministry of Agriculture, Forestry and Fisheries, 1992). ). (A) The elution rate of the coated granular fertilizer in the requirements is obtained by, for example, the following method.

<(A) Elution rate of fertilizer components in requirements>
10 g of coated granular fertilizer and 200 ml of distilled water at 25 ° C. were added to the container and allowed to stand at 25 ° C. After 7 days, all the water was removed from the container and the amount of fertilizer component eluted in the water was determined. After that, water was drained every 7 days. After draining the water, the coated granular fertilizer and 200 ml of distilled water were put into the container again and allowed to stand in the same manner, and then an operation was performed to determine the amount of fertilizer component eluted in the water. By repeating the above operation, the integrated value of the fertilizer component eluted in the water is obtained, and the ratio of the fertilizer component amount eluted in the water to the total fertilizer component amount contained in the coated granular fertilizer is defined as the elution rate of the fertilizer component in the requirement (A). do.

Further, the coated granular fertilizer satisfying the requirement (A) is naturally a coated granular fertilizer having no film defect because it has a high elution control function, but the elution rate of the fertilizer component after 1 day in water at 25 ° C. is measured. After confirming that there is no film defect in the coated granular fertilizer produced by the above (the elution rate of the fertilizer component after 1 day in 25 ° C. water is 50% by mass or less), <(A) coated granular fertilizer in the requirement. You can also check the elution rate of fertilizer>. Therefore, <elution rate of fertilizer component in (A) requirement> can be measured by the following method.

10 g of coated granular fertilizer and 200 ml of distilled water at 25 ° C. were added to the container and allowed to stand at 25 ° C. After 1 day, all the water was removed from the container to determine the amount of fertilizer component eluted in the water, and the ratio of the amount of fertilizer component eluted in water to the total amount of fertilizer component contained in the coated granular fertilizer was 25 ° C. after 1 day in water. The elution rate of the fertilizer component of. In the above-mentioned measurement of the elution rate of fertilizer components in 25 ° C water after 1 day, the coated granules after draining water from the container and then measuring the elution rate of fertilizer components in 25 ° C water after 1 day. The fertilizer and 200 ml of fresh distilled water were placed again in a container in which the elution rate of the fertilizer component was measured after 1 day in water at 25 ° C., and the mixture was allowed to stand in the same manner. After 6 days, all the water was drained from the container in the same manner. After that, water was drained every 7 days. After draining the water, the coated granular fertilizer and 200 ml of distilled water were put into the container again and allowed to stand in the same manner, and then an operation was performed to determine the amount of fertilizer component eluted in the water. By repeating the above operation, the integrated value of the fertilizer component eluted in the water is obtained, and the ratio of the fertilizer component amount eluted in the water to the total fertilizer component amount contained in the coated granular fertilizer is defined as the elution rate of the fertilizer component in the requirement (A). do.

The "timed elution type" of the elution pattern in the present invention means a period in which elution is suppressed within a certain period after fertilization (elution suppression period) and a period in which elution is started and sustained after the elution period (elution period). ) Means to have.

In the present invention, the elution suppression period is defined as the number of days until the elution rate of the fertilizer component in 25 ° C. water of the coated granular fertilizer reaches 10% by mass (hereinafter referred to as d1). Similarly, if the elution period is defined as the number of days (hereinafter referred to as d2) until the elution rate of the fertilizer component exceeds 10% by mass and reaches 80% by mass, the elution pattern of the "timed elution type" is defined in the present invention. It refers to an elution pattern in which the ratio of d1 / d2 is preferably 0.1 or more, more preferably 0.15 or more. More preferably, d1 is 1 to 150 (days), and more preferably 5 to 150 (days). As long as d1 and d1 / d2 of the coated granular fertilizer are in the above range, various cultivation methods can be applied.

The elution rate of the coated granular fertilizer component can be measured in the same manner as the measurement of <the elution rate of the fertilizer component in the requirement (A)> described in the paragraph.

The method of coating the surface of the granular fertilizer with the coating material is not particularly limited, and for example, a method of spraying the melt-dispersed coating material on the surface of the core material, or a coating material in which the coating material is dissolved and dispersed (or suspended) in a solvent. Is sprayed on the surface of the core material (dissolution spray method), a method of spraying a monomer on the surface of the core material and reacting on the surface to form a resin (coating), and a dip method of immersing the core material in the coating material. Known techniques can be used. Among these, the solution spraying method is preferable.

Examples of the coating method include a pan coating method, a jet layer coating method, a fluidized bed coating method, a rolling coating method, a dry coating method, or a combination method thereof. In the present invention, a jet layer covering method or a fluidized bed covering method is preferable.

In the production method of the present invention, a coating device having a fluidized bed or a jet layer is used, a fluidized gas containing a solvent discharged from the coating device is dusted with a dust remover, and then the solvent is recovered with a condenser and / or activated charcoal. A method of heating the gas separated by the condenser with a heater and circulating and reusing the recovered solvent and the heated gas, which comprises the following steps (A) to (D) to produce a coated granular fertilizer. The method.
Step (A): toluene, the solvent comprising one or more selected from tetrachlorethylene and trichlorethylene, in the resin 100 wt%, contains 90 to 95 wt% of MgO and SiO ₂ in total, and the Al ₂ O ₃ A step of preparing a coating liquid by dissolving or suspending a coating material containing high-purity talc containing 1.5% by mass or less;
Step (B): A step of spraying the coating liquid on the granular fertilizer under a flowing gas stream in the coating device and evaporating and drying the solvent in the coating liquid to form a film on the surface of the granular fertilizer;
Step (C): By degassing and removing the solvent contained in the granular fertilizer having the film formed by the step (B) by ventilation, the concentration thereof is 500 ppm or less with respect to the granular fertilizer having the film formed. And step (D): a step of recovering the solvent from the solvent-containing gas after the degassing treatment by ventilation in the step (C) using a condenser and / or activated charcoal.

As an example, the fluidized bed covering method will be described with reference to the covering device shown in FIG. The fluidized gas flows from the lower part to the upper part of the fluidized bed 1 and passes through the dust collector 6, the gas is cooled by the condenser 7, and the solvent is condensed and recovered. The gas that has passed through the condenser 7 is heated by passing through the heater 12 and circulated so as to be guided to the fluidized bed 1 again as hot air 4. By adopting such a closed system, the solvent is not discharged to the outside. The flow of gas is performed by the blower 8, but the installation position is not particularly limited.

The granular fertilizer was charged from the inlet installed on the side surface of the fluidized bed 1 and made into a fluidized state by the fluidized gas introduced from the lower part of the fluidized bed 1 and the stirring blade installed at the bottom of the fluidized bed 1. At this time, the granular fertilizer temperature can be adjusted by the flow rate of the flowing gas, the temperature of the flowing gas, and the like. The fluidized gas flow rate was adjusted while measuring with a flow meter, and the fluidized gas temperature was adjusted while measuring the granular fertilizer temperature and the exhaust temperature (fluidized bed 1 upper temperature).

For the coating liquid in the step (A), a coating material is weighed by adding a surfactant or the like to the resin and high-purity talc as necessary, and the coating material is dissolved and suspended in a solvent in the dissolution tank 9. To prepare. In order to uniformly disperse the solvent-insoluble material such as talc in the coating liquid, it is preferable to perform strong stirring.
In the coating liquid, the ratio of the coating material is usually preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, and further preferably 2 to 10% by mass.

In the step (B), the coating device transports the coating liquid to the particles 3 (granular fertilizer) in a fluidized state by using a pump 10 via a pipe, sprays the coating liquid with a spray nozzle 2, and sprays the coating liquid on the particles 3. At the same time as spraying on the surface, a high-temperature fluidized gas is sprayed from the lower part of the fluidized bed 1 in parallel to evaporate and dry the solvent in the coating liquid adhering to the surface of the granular fertilizer. The spraying time varies depending on the concentration of the resin in the coating liquid, the spraying speed of the coating liquid, the coating rate, and the like, but these should be appropriately selected according to the purpose.

As the ventilation in the step (C), a heated gas such as nitrogen, air, or water vapor, which contains almost no solvent, or at least 500 ppm or less of the solvent, is preferable. Further, the degassing may be performed by using the covering device, but may be performed by a degassing device different from the covering device.

The refrigerant used for the condenser used in the step (D) is not particularly limited, and known ones can be used. It is preferable that the activated carbon is granular because it is easy to handle. In order to treat the solvent-containing gas after the degassing treatment containing a large amount of solvent in the step (D), it is preferable to reduce the solvent concentration to some extent with a condenser and then use activated carbon in combination.
The recovered solvent can be reused in the step (A).

As a covering device that can be used in the present invention other than the covering device shown in FIG. 1, it is disclosed in Japanese Patent Publication No. 42-24281 and Japanese Patent Publication No. 42-24282 as a fluidized bed type or jet layer type covering device. Another example is a device in which a fountain-type fluidized bed of granular fertilizer is formed by a gas body and a coating agent is sprayed on a granular fertilizer dispersion layer generated in the center. As the rotary type covering device, the powder or granular material is transferred upward by the lifter provided on the inner circumference of the drum by the rotation of the drum disclosed in JP-A-7-31914 and JP-A-7-195007, and then dropped. An apparatus can be mentioned in which a coating agent is applied to the surface of the falling powder or granular material to form a film.

The compound fertilizer of the present invention is a compound fertilizer obtained by mixing the coated granular fertilizer of the present invention and the uncoated granular fertilizer. Specifically, it contains one or more coated granular fertilizers containing one or more selected from nitrogen, phosphoric acid, and potassium as fertilizer components and one or more uncoated granular fertilizers.
More specifically, the coated granular fertilizer containing one or more selected from nitrogen, phosphoric acid, and Kari as fertilizer components is a coated granular fertilizer containing nitrogen, phosphoric acid, and Kari individually, but nitrogen and phosphorus. It may be a coated granular fertilizer containing all of acid and Kari. Further, for example, a coated granular fertilizer having a different elution behavior of nitrogen may be used. Urea, which is a nitrogenous fertilizer having a high fertilizer component content, is preferable.

The form of the uncoated granular fertilizer is not particularly limited, but a spherical one is preferable, and the particle size is usually 1.0 to 5.0 mm, and 1.0 to 4.5 mm with respect to the total granular fertilizer particles. The content ratio of the particles is 95% by mass or more. The particle size can be separated by, for example, a sieve. Examples of uncoated granular fertilizers include ammonia sulfate, urea, and ammonia nitrate, as well as isobutylaldehyde condensed urea and acetaldehyde condensed urea. Examples of phosphoric acid fertilizers include superphosphate lime, molten phosphorus fertilizer, calcined phosphorus fertilizer and the like. Examples of potassium fertilizers include potassium sulfate, potassium chloride, and potassium silicate fertilizer.
Further, advanced chemical fertilizers and compound fertilizers having a total component amount of 30% or more of the three elements of fertilizer (nitrogen, phosphoric acid, potassium), chemical fertilizers including organic fertilizers, and organic fertilizers may be used.

The compounding ratio of the compounded fertilizer of the present invention is not particularly limited, but 20 to 90% by mass, preferably 30 to 90% by mass, of the total nitrogen of the compounded fertilizer can be contained as the compounded fertilizer.
As a blending method, a known mixing technique can be applied. For example, examples of the stirring type include a rotary drum type, a mixing cone type, a cumulative type in which a TVA type compounding tower and the like are compounded while falling under their own weight.

The coated granular fertilizer or compound fertilizer of the present invention can be applied to any plant cultivation, and is particularly suitable as a fertilizer used in the total basal fertilizer application method for paddy rice. As an application method, full-thickness fertilizer, side-row fertilizer, or surface-layer fertilizer in Honda is preferable, and among the coated granular fertilizers of the present invention, a super-high fertilizer such as a nursery box full-volume fertilizer applied at the time of sowing using a timed elution type. According to the labor-saving application, after the seedlings grown with the fertilizer are transplanted, the cultivation management according to the conventional method is performed, so that the yield higher than the conventional method can be secured without additional fertilizer.

The method for cultivating a plant of the present invention is a cultivation method using the coated granular fertilizer of the present invention or the compound fertilizer of the present invention.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto. Unless otherwise specified, "%" in the following examples means mass%.

1. 1. Physical characteristics of talc Various physical properties of talc used in the present invention were measured. The median diameter D50 was based on the laser diffraction method, the whiteness was based on the Hunter method, and the water content was based on JIS K5101. The purity of the height of Table 1 includes 90 to 95 wt% of MgO and SiO ₂ contained in the talc in total, and was a high urban those containing Al ₂ O ₃ more than 1.5 wt%, the rest low .. Table 1 shows the physical characteristics of talc used in producing the coated granular fertilizers of Examples and Comparative Examples.

(Example 1)
2. 2. Production of Coated Granular Fertilizer Using the production equipment shown in FIG. 1, a film was formed on the surface of the granular fertilizer (granular urea) by the following method. In the manufacturing apparatus, the hot air 4 flows from the lower part to the upper part of the fluidized bed 1 and passes through the dust collector 6, the gas is cooled by the condenser 7, and the solvent is condensed and recovered. The gas that has passed through the condenser 7 is heated from the blower 8 through the heater 12 and circulated so as to be guided to the fluidized bed 1 again as hot air 4. By adopting such a closed system, the solvent is not discharged to the outside.

As the particles 3, 15 kg of granular urea (particle diameter 3.0 to 4.0 mm, average particle size 3.3 mm, circularity coefficient 0.9) is charged from the charging port installed on the side surface of the fluidized bed 1, and the fluidized bed is charged. The hot air 4 introduced from the lower part of 1 and the stirring bath installed at the bottom of the fluidized bed 1 were brought into a fluidized state. At this time, the hot air flow rate and the hot air temperature were adjusted so that the particle temperature was 60 ± 2 ° C. The hot air flow rate was adjusted while measuring with a flow meter installed between the blower 8 and the fluidized bed 1, and the hot air temperature was adjusted while measuring the particle temperature and the exhaust temperature (fluidized bed 1 upper temperature).

On the other hand, polyethylene (low density polyethylene, density 0.923 g / cm ³ (JIS K 6760), melt flow rate (MFR) 0.3 g / 10 min. , JIS K 7210-1)) 30 parts by mass, ethylene-vinyl acetate copolymer (trade name "Evaflex 360" (manufactured by Mitsui DuPont Polychemical Co., Ltd.)) 10 parts by mass, Tarku A (median diameter D50 = 10 μm) By adding 60 parts by mass, 1 part by mass of polyoxyethylene monostearate, 0.01 part by mass of iron stearate and 1900 parts by mass of tetrachloroethylene as a coating solution solvent, and mixing and stirring at 100 ± 2 ° C. for 30 minutes. The resin was dissolved to prepare a uniform spray solution 5 having a concentration of 5% by mass. The dissolution tank 9 was constantly stirred until the coating was completed.

The spray liquid 5 was transported to the spray nozzle 2 installed above the fluidized bed 1 at a flow rate of about 110 kg / h, and sprayed onto the granular urea in the fluid. Tetrachlorethylene contained in the sprayed liquid is condensed and recovered by the condenser 7, stored in the tank 11, and guided to the dissolution tank 9.

The above-mentioned coating operation was started when the temperature of the granular urea in flow reached 60 ° C. and was carried out until the coating amount became 8% by mass with respect to the final coated granular fertilizer. Then, while keeping in mind that the particle temperature was maintained at 60 ± 2 ° C., the temperature of the hot air 4 was adjusted, and only the hot air 4 was blown for 10 minutes to perform drying. A coating having a coating that controls the elution rate by discharging the coated granular urea at the end of drying from the extraction port 13 at the bottom of the fluidized bed 1 and then performing a ventilation treatment for 0.5 to 1 hour. Granular fertilizer (Example 1) was obtained. The solvent content in the coated granular fertilizer after ventilation was 500 ppm or less. The solvent-containing gas after the degassing treatment by ventilation was separated and adsorbed using activated carbon, and then recovered.
Manufacturing conditions for coated granular fertilizer Granular urea: 15 kg
Particle temperature during coating: 60 ° C
Melting temperature: 100-110 ° C
Spray temperature: 80-100 ° C
Hot air temperature: 130-140 ° C
Spray flow rate: 108 kg / h

(Examples 2 to 4, Comparative Examples 1 to 2)
For Examples 2 to 4 and Comparative Examples 1 to 2, the coated granular fertilizer was produced in the same manner except that the talc of Example 1 was changed as shown in Table 1.

3. 3. Film strength 50 particles of coated granular fertilizer (hereinafter referred to as sample) obtained in Examples and Comparative Examples are cut on two sides with a cutter knife (Cutter Knife S, manufactured by PLUS Corporation) one by one and allowed to stand in water. Then, the granular fertilizer inside is removed and dried to prepare a ring-shaped film having a width of about 2.0 mm. The load required to cut the ring was measured using a digital force gauge (model FGP-0.5, manufactured by Nidec-Shimpo Co., Ltd.) for the produced ring-shaped film. The obtained value [N] was taken as the film strength and evaluated according to the following criteria.
AA ... The film strength was 0.5 N or more.
BB: The film strength was 0.2 N or more and less than 0.5 N.
CC ... The film strength was less than 0.2N.

4. Elution measurement of coated granular fertilizer <Elution rate of fertilizer components after 1 day in water at 25 ° C>
The elution behavior in water was measured for the coated granular fertilizers (hereinafter referred to as samples) obtained in Examples and Comparative Examples. 10 g of the samples obtained in Examples and Comparative Examples and 200 ml of distilled water adjusted to 25 ° C. were added to a plastic container with a lid and allowed to stand in an incubator set at 25 ° C. After 1 day, all the water was extracted from the container, and the amount of urea (urea elution amount) contained in the extracted water was determined by quantitative analysis (dimethylaminobenzaldehyde method "detailed fertilizer analysis method 2nd revised edition" Yokendo). The elution rate of the fertilizer component after 1 day was determined.

<(A) Elution rate of fertilizer components in requirements>
In the above measurement of <elution rate of fertilizer component after 1 day in 25 ° C water>, after draining water from the plastic container, <elution rate of fertilizer component after 1 day in 25 ° C water> was measured. The later sample and 200 ml of fresh distilled water were placed in the container again and allowed to stand in the same manner. After 6 days, all the water was drained from the container in the same manner, and the water was drained every 7 days thereafter. This operation was repeated until the integrated value of the urea elution amount reached 80% by mass of the urea content previously measured using the same lot of coated granular fertilizer.

Then, the samples of the examples and comparative examples were ground in a mortar, the contents of the samples were dissolved in 200 ml of water, and the remaining amount of urea was quantitatively analyzed by the same method as described above. The total amount of urea is the sum of the accumulated urea elution amount and the remaining amount of urea, and the relationship between the cumulative elution amount of urea eluted in water and the number of days is graphed to create an elution rate curve, and the number of days to reach 80% by mass elution rate (d80). ) Was asked. d80 was evaluated according to the following criteria.
AA ... The elution period was extended by 10 days or more as compared with Comparative Example 1 (75 days).
BB: Compared with Comparative Example 1 (75 days), the elution period was prolonged by 1 day or more and less than 10 days.
CC ... Compared with Comparative Example 1 (75 days), the elution period was prolonged by less than 1 day, the elution period did not change, or the elution period was shortened.

As described above, it was confirmed that Examples 1 to 4 had a longer elution period as compared with Comparative Examples 1 and 2. Further, the film strength of Examples 1 to 4 was improved, and the characteristics suitable for mechanical fertilization could be imparted. The elution rate of the fertilizer component after 1 day of Examples 1 to 4 was 50% by mass or less. Therefore, it was found that the coating film containing high-purity talc is a useful technique for thinning the coating film.

(Examples 5 to 7, Comparative Example 3)
The coated granular fertilizer was produced in the same manner as in Example 1 except that the coverage was 3, 5, and 12% (Examples 5 to 7). Further, a coated granular fertilizer of Comparative Example 3 was obtained in the same manner as in Comparative Example 1 except that the coverage was 5%.

5. Mechanical fertilizer application test Using a backpack type power spreader (DMD-5501-26, manufactured by Kyoritsu Co., Ltd.), 10 kg of coated granular fertilizer was sprayed under the conditions of engine throttle 8 and shutter opening 10, and coated granular fertilizer was discharged 10 m or more from the cylinder tip. Fertilizer was recovered. The recovered coated granular fertilizer is reduced to 50 g by a splitter, and combined with 10 g of the coated granular fertilizer before the test, described in 4. above. The analysis was performed according to the elution measurement of the coated granular fertilizer, and the elution rate was calculated. The elution rate on the 10th day was evaluated according to the following criteria.
AA ... The difference in elution rate between before and 10 days after the test was less than 3% by mass, and the elution behavior was hardly affected.
BB: The difference in elution rate between before and 10 days after the test was 3% by mass or more and less than 10% by mass, and the elution behavior was slightly affected.
CC: The difference in elution rate between before and 10 days after the test was 10% by mass or more, and the elution behavior was greatly affected.

As shown in Table 3 above, in Examples 5 to 7, the coverage was changed, but the influence of mechanical fertilization was not present or was slight. It is clear that the elution period d80 becomes longer as the coverage increases, the elution period can be controlled by the coverage, and a long elution period of 100 days or more can be obtained.
Since Comparative Example 3 is affected by mechanical fertilization, its usage and usage are limited.

(Examples 8 to 13, Comparative Examples 4 to 5)
6. Production of timed-eluting coated granular fertilizer (effect of coating composition)
As shown in Table 4, the coated granular fertilizers (Examples 8 to 13) in which the elution pattern shows a timed elution type according to Example 1 in each Example and Comparative Example 1 except for changing the coating material composition and the like. Comparative Examples 4 to 5) were manufactured.

ＰＥ：ポリエチレン（低密度ポリエチレン、密度０．９２３ｇ／ｃｍ³（ＪＩＳ Ｋ ６７６０）、メルトフローレート（ＭＦＲ）０．３ｇ／１０ｍｉｎ．（測定温度１９０℃、荷重３．１８Ｎ、ＪＩＳ Ｋ ７２１０−１））
ＥＶＡ：エチレン−酢酸ビニル共重合体（商品名「エバフレックス３６０」（三井デュポンポリケミカル株式会社製））
コーンスターチ：商品名ＬＭスターチ、王子コーンスターチ株式会社製
ＳＡ：界面活性剤、ポリオキシエチレンモノステアレート ＨＬＢ８．０（商品名 ノニオンＳ−２、日油株式会社製）
Ｆｅ１：ステアリン酸鉄（ＩＩＩ）
Ｆｅ２：アセチルアセトン第二鉄

PE: Polyethylene (low density polyethylene, density 0.923 g / cm ³ (JIS K 6760), melt flow rate (MFR) 0.3 g / 10 min. (Measurement temperature 190 ° C., load 3.18 N, JIS K 7210-1) )
EVA: Ethylene-vinyl acetate copolymer (trade name "Evaflex 360" (manufactured by Mitsui DuPont Polychemical Co., Ltd.))
Cornstarch: Product name LM Starch, manufactured by Oji Cornstarch Co., Ltd. SA: Surfactant, polyoxyethylene monostearate HLB8.0 (Product name Nonion S-2, manufactured by NOF Corporation)
Fe1: Iron stearate (III)
Fe2: Acetylacetone ferric

In the obtained Examples 8 to 13 and Comparative Examples 4 to 5, the above 4. The analysis was performed according to the elution measurement of the coated granular fertilizer.
Further, the number of days from the start of elution measurement to 10% by mass elution was defined as "d1", and the number of days thereafter from the start to 80% by mass elution was defined as "d2". The results are shown in Table 5.

As is clear from this result, it is clear that the elution of Example 8 of the timed elution type coated granular fertilizer of the present invention is suppressed as compared with Comparative Example 4.
Further, in Examples 8 to 13, d1 / d2 was 0.1 or more. Therefore, it is possible to supply the fertilizer component after suppressing elution in the required amount at the required time, and it is possible to supply such a high-performance product containing more fertilizer components at low cost.
In Comparative Example 4, the elution was fast and the elution period was short. In addition, the film strength was inferior to that of the examples.
In Comparative Example 5, the particles were repeatedly bonded and detached during production, and film defects were observed.

7. Production of compound fertilizer The compound fertilizer was produced as follows using the coated granular fertilizer of the example. Chemical fertilizers of coated granular fertilizers and uncoated granular fertilizers produced above (sulfated ammonium phosphate 300, N-P ₂ O _5- K ₂ O = 3.5 (%) -20.5 (%) ) -20.5 (%), manufactured by J-Cam Agri Co., Ltd.) was mixed at a mass ratio of 30:70 to obtain the compound fertilizer of the present invention.
After production, compound fertilizer was collected and the state of the film was observed. As a result, no film defect was observed, and it was found that the necessary and sufficient film strength was secured.

8. Cultivation test The above 7. containing the coated granular fertilizer of Example 8 and Comparative Example 4. A cultivation test of paddy rice (cultivar "Hinohikari") was conducted using the compound fertilizer produced in the production of compound fertilizer. Paddy rice seedlings were cultivated according to the customary law and transplanted to paddy fields in Samejima, Fuji City, Shizuoka Prefecture. The above compound fertilizer was cultivated according to the conventional method except that the same amount of side row fertilizer was applied at the same time as transplanting. No additional fertilizer is applied.

As a result, the yield of paddy rice in the test plot cultivated with the compound fertilizer containing Example 8 was better than that in the test plot using Comparative Example 4. The compound fertilizers including Comparative Example 4 had better leaf color after transplanting than those in the Example group, but had more ineffective stalks and less effective stem ratio. From this, it is considered that the fertilizing effect was effective in the test plot cultivated in Example 8.

1. 1. Fluidized bed 2. Spray nozzle 3. Particles 4. Hot air 5. Spray liquid 6. Dust collector 7. Condensator 8. Blower 9. Melting tank 10. Pump 11. Tank 12. Heater 13. Extract

Claims (12)

It has a granular fertilizer containing one or more fertilizer components and a film covering the surface of the granular fertilizer.
The coating is formed from a coating material containing resin and high-purity talc.
The high purity talc in 100% by mass, containing 90 to 95 wt% of MgO and SiO ₂ in total, and including Al ₂ O ₃ 1.5 mass% or less, coated granular fertilizers. The coated granular fertilizer according to claim 1, which contains 2 to 15% by mass of a coating in 100% by mass of the coated granular fertilizer. The coated granular fertilizer according to claim 1 or 2, which contains 10 to 80% by mass of a thermoplastic resin and 20 to 90% by mass of the high-purity talc in 100% by mass of the coating material. The coated granular fertilizer according to any one of claims 1 to 3, wherein the coating material contains one or more selected from a surfactant, a polysaccharide and a derivative of the polysaccharide. The coated granular fertilizer according to any one of claims 1 to 4, wherein the median diameter of the high-purity talc is in the range of 6 to 30 μm. The coated granular fertilizer according to any one of claims 1 to 5, wherein the high-purity talc has a whiteness of 85 or more. The coated granular fertilizer according to any one of claims 1 to 6, which contains 0.5% by mass or less of water in 100% by mass of high-purity talc. The invention according to any one of claims 1 to 7, wherein the period until the elution rate of the fertilizer component reaches 80% by mass when the coated granular fertilizer is immersed in water at 25 ° C. is 10 to 500 (days). Coated granular fertilizer. It is a coated granular fertilizer whose elution pattern shows a timed elution type.
The period until the elution rate of the fertilizer component reaches 10% by mass is d1 (day).
When the period until the elution rate of the fertilizer component exceeds 10% by mass and reaches 80% by mass is d2 (day),
The coated granular fertilizer according to any one of claims 1 to 8, wherein d1 / d2 is 0.1 or more and d1 is in the range of 5 to 150 (days). A compound fertilizer obtained by mixing the coated granular fertilizer according to any one of claims 1 to 9 with an uncoated granular fertilizer. Using a coating device having a fluidized bed or a jet layer, the fluidized gas containing the solvent discharged from the coating device was dusted with a dust remover, and then the solvent was recovered by a condenser and / or activated charcoal, and separated by the condenser. A method for heating a gas with a heater and circulating and reusing the recovered solvent and the heated gas, the method for producing a coated granular fertilizer, which comprises the following steps (A) to (D).
Step (A): In the solvent containing one or more selected from toluene, tetrachlorethylene and trichlorethylene.
Resin and 100 mass%, contains 90 to 95 wt% of MgO and SiO ₂ in total, and dissolved or suspended not by coating a coating material comprising a high purity talc containing Al ₂ O ₃ more than 1.5 wt% The process of preparing the liquid;
Step (B): A step of spraying the coating liquid on the granular fertilizer under a flowing gas stream in the coating device and evaporating and drying the solvent in the coating liquid to form a film on the surface of the granular fertilizer;
Step (C): By degassing and removing the solvent contained in the granular fertilizer having the film formed by the step (B) by ventilation, the concentration thereof is 500 ppm or less with respect to the granular fertilizer having the film formed. And step (D): a step of recovering the solvent from the solvent-containing gas after the degassing treatment by ventilation in the step (C) using a condenser and / or activated charcoal. A method for cultivating a plant using the coated granular fertilizer according to any one of claims 1 to 9 or the compound fertilizer according to claim 10.

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