JPH09286685A - Production of coated granular fertilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrially favorable method using an aqueous solvent for producing a slow-release fertilizer having an excellent preservable property and a fertilizer elution control characteristic. SOLUTION: In the production method of a coated granular fertilizer, after forming the first coated layer containing an alkali substance on a surface of the granular fertilizer, the second coated layer is formed by applying an aqueous emulsion containing a mixture of an alkaline water soluble polymer substance and an alkaline water-insoluble polymer substance at its outside. Or, the coating of the water insoluble polymer is executed by heating and drying the surface of the granular fertilizer while treating or after treating the surface of the granular fertilizer (may be coated with the coated layer) with a polymer aq. soln. in which water-insoluble/alkaline water-soluble polymer substance is dissolved in an alkaline water.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a coated granular fertilizer, and in particular, it is possible to arbitrarily adjust the elution start time of fertilizer components in a water-containing medium or water,
The present invention also relates to a method for producing a coated granular fertilizer, which enables production of a coated granular fertilizer having good long-term storage stability under industrially advantageous conditions.

[0002]

2. Description of the Related Art In recent years, in agriculture in Japan, the agricultural labor force is becoming weak due to the aging of agricultural workers and depopulation of rural areas. For this reason, the labor saving of agricultural work is attempted by mechanization of fertilizer application and use of slow-release fertilizer. The slow-release fertilizer is a fertilizer that suppresses the elution rate of the fertilizer applied, and the use of such slow-release fertilizer can reduce the number of fertilizer applications. In addition, as a slow-release fertilizer,
There is also a fertilizer elution control slow-release fertilizer designed to release the required amount of fertilizer at the required time according to the growth process of the crop. It has attracted attention because it has the advantage that fertilizer can be applied once. An example of a fertilizer elution control type slow-release fertilizer is described in JP-A-4-202078. That is, in the fertilizer elution control slow-release fertilizer described in this publication, a first coating layer containing an alkaline substance is formed on the surface of a granular fertilizer, and then the surface of the first coating layer is highly soluble in alkaline water. It has a structure in which a second coating layer made of a mixture of a molecular substance and an alkaline water-insoluble polymer substance is formed. Since the coated granular fertilizer having such a structure can easily control the elution start time of the fertilizer component particularly in the water-containing medium or water, it can be said to be an advantageous fertilizer elution control slow-release fertilizer. However, the coating operation of the granular fertilizer according to the method described in this publication is performed by dissolving the coating material in an organic solvent, and thus the working environment easily deteriorates.
There is a problem that a trace amount of organic solvent tends to remain in the film, and further improvement is desirable in practical use.

As a method for coating fertilizer particles without using an organic solvent, as a coating resin material as described in JP-A-53-138870, JP-A-60-103093 and the like. A method is known in which polyvinyl alcohol is used to prepare a coating layer-forming solution in which it is dissolved in water, the surface of the fertilizer particles is treated with this solution, and the coated granular fertilizer is obtained. However, the coated granular fertilizer coated with a water-soluble resin such as polyvinyl alcohol dissolves quickly when it is applied in water, so there is a problem that it is difficult to be a target fertilizer elution control slow-release fertilizer. When the fertilizer particles to be coated are ammonium sulfate (ammonium sulfate) fertilizer particles, polyvinyl alcohol as a coating material tends to be twisted in the coating layer, so that the coating layer is formed within a short time after the coating layer is formed. Another problem is that the coating layer begins to deteriorate.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides an industrially advantageous method for producing a slow-release fertilizer using a water-based solvent, which has excellent preservability and fertilizer dissolution control properties. To aim. Another object of the present invention is to provide an industrially advantageous method using an aqueous solvent for producing a slow-release fertilizer having excellent storage properties and film properties.

[0005]

According to the present invention, after forming a first coating layer containing an alkaline substance on the surface of a granular fertilizer, an alkaline water-soluble polymer substance and an alkaline water-insoluble polymer substance are formed on the outside thereof. A method for producing a coated granular fertilizer characterized in that an aqueous emulsion containing a mixture is coated and dried to form a second coating layer. The second coating layer thus formed is preferably further heated depending on the coating material.

According to the present invention, the surface of the granular fertilizer or any one of the coated fertilizers having a coating layer on the surface of the granular fertilizer is treated with a water-insoluble and alkaline water-soluble polymer substance which is alkaline water. There is also a method for producing a coated granular fertilizer coated with a water-insoluble polymer substance, which is characterized in that it is heated or dried while being treated with an aqueous solution of an alkali water-soluble polymer substance dissolved in. When used as a salt of a water-insoluble polymer substance with ammonia or a water-soluble amine, the alkaline water-soluble polymer substance used in this production method releases ammonia or a water-soluble amine to be water-insoluble by subsequent heating and drying. It is preferably a substance.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The granular fertilizer to be coated in the production method of the present invention is not particularly limited. However, the coated fertilizer of the present invention can be particularly advantageously utilized for granular fertilizers that do not release ammonia or leave a small amount of ammonia when left in the air at a temperature near room temperature. Examples of such granular fertilizers are urea, sodium nitrate, aldehyde condensed urea, isobutyraldehyde condensed urea, nitrogenous fertilizers such as ammonia sulfate, fertilizer, calcined phosphate fertilizer, processed phosphate fertilizer, mixed phosphate fertilizer. , Phosphorus fertilizers such as corrosive acid phosphorus fertilizer, potassium sulfate, potassium chloride, potassium potassium sulfate, potassium bicarbonate, potassium fertilizer such as potassium silicate fertilizer, monoammonium phosphate, potassium phosphate, potassium nitrate, etc. Examples thereof include fertilizers, organic fertilizers, and the like, and granular fertilizers obtained by granulating a mixture of these fertilizers by a method known per se or a method similar thereto. The particle size of the granular fertilizer is not particularly limited, but usually the particle size is 1 to 4
Granular fertilizers in the mm range are used.

The alkaline substance introduced into the first coating layer of the coated granular fertilizer in which a plurality of coating layers are provided on the surface of the granular fertilizer of the present invention is an inorganic or organic compound which exhibits alkalinity in an aqueous solution, particularly at room temperature. It is preferable that the alkaline substance is a solid (preferably a fine powder) and exhibits an alkalinity by gently reacting with water. In particular, inorganic alkaline substances such as alkaline earth metal carbonates, hydroxides or oxides, alkali metal carbonates, phosphates or silicates, and alkali metal organic acid salts, and alkylamines. Amine-based organic compounds such as classes can be advantageously used. Specific examples of particularly advantageous alkaline substances include calcium carbonate, calcium oxide, calcium hydroxide, magnesium carbonate, magnesium oxide, magnesium hydroxide, sodium carbonate, potassium carbonate, dipotassium phosphate, tripotassium phosphate, and sodium silicate. , Sodium acetate and the like.

The alkaline material of the first coating layer is preferably used together with a spreading material which is usually a resinous material such as ethylene vinyl acetate copolymer to form the coating layer. The spreading material that is preferably used for forming the first coating layer is an emulsion (emulsion) containing a water-based solvent as a dispersion medium.
It is advantageous to use in type.

The amount of the alkaline substance contained in the first coating layer is 0.05 to 20 times by weight, particularly 0.1 to 10 times by weight, the amount of the alkaline water-soluble polymer substance contained in the second coating layer. It is preferably in the range. If the coating amount of the alkaline substance is too small relative to the coating amount of the alkaline water-soluble polymeric substance, the alkaline water-soluble polymeric substance contained in the second coating layer (outer coating layer) will be sufficiently eluted after fertilization with the coated fertilizer. Therefore, the start time of fertilizer elution may be too late, or the elution rate of fertilizer after the start of fertilizer elution may be slow, which is not preferable. on the other hand,
When the amount of the alkaline substance is larger than the coating amount of the alkaline water-soluble polymer substance, the elution start time of the fertilizer is early, and the elution rate of the fertilizer after the elution is started is high. However, if the amount of the alkaline substance is too large, the elution start time becomes too early, which is not preferable. Further, if the amount of the alkaline substance is excessively increased, the relative amount of the fertilizer component in the coated granular fertilizer decreases, and the economic efficiency deteriorates.

In the coated granular fertilizer of the type in which a plurality of coating layers are provided on the surface of the granular fertilizer of the present invention, an alkaline water-soluble polymer substance and an alkaline water-insoluble high polymer are provided on the outer side of the first coating layer. An aqueous emulsion containing a mixture with a molecular substance is coated and dried to form a second coating layer.

The alkaline water-soluble polymer substance is a polymer substance which is insoluble in ordinary water (neutral or slightly acidic water) and is soluble in, for example, an alkaline water solvent having a pH of 8 or more. Examples of such an alkaline water-soluble polymer substance include a copolymer of an unsaturated compound having a carbon-carbon unsaturated group and an unsaturated carboxylic acid or a derivative thereof, and a rosin treated to be soluble in alkaline water. An example is a resin. Alternatively, a polymer substance which is a salt of a water-insoluble polymer substance described below and ammonia or a water-soluble amine and releases ammonia or a water-soluble amine to be water-insoluble by subsequent heating and drying can also be advantageously used. it can. Examples of the unsaturated compound having a carbon-carbon unsaturated group include alkylene unsaturated compounds (eg, ethylene, propylene, n-butylene, isobutylene), unsaturated carboxylic acid esters (eg, methyl methacrylate, acryl). Butyl acid, 2-ethylhexyl acrylate, glycidyl methacrylate, 2-acrylic acid
Hydroxyethyl, diethylene glycol acrylate, trimethylolpropane triacrylate), aromatic vinyl compounds (eg, styrene, vinyltoluene, divinylbenzene), vinyl cyan compounds (eg, acrylonitrile, methacrylonitrile), aliphatic dienes (eg, butadiene, Isoprene), halogen-substituted vinyl compounds (eg, vinyl chloride), carboxylic acid vinyl esters (eg,
Vinyl acetate) and vinylamide compounds (eg, acrylamide, N-methylol-acrylamide, N-butoxymethylacrylamide).

Examples of the above unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid and maleic anhydride. Especially preferred are acrylic acid, methacrylic acid, and maleic anhydride. The above-mentioned copolymer of an unsaturated compound having a carbon-carbon unsaturated group and an unsaturated carboxylic acid preferably has a molar ratio of the former to the latter in the range of 30:70 to 70:30, and particularly 40 It is desirable to be in the range of: 60 to 60:40. A part (preferably within 10 mol%, particularly within 5 mol%) of these monomer components may be replaced with another monomer component (eg, butadiene, isoprene). Further, as the alkaline water-soluble polymer substance, the following unsaturated carboxylic acid [A] and (meth) acrylic acid ester [B]: R-CH = CH-COOH [A] R 1 -CH = CH-COOR 2 [ B] (wherein R and R ¹ each independently represent hydrogen or methyl, and R ² represents an alkyl group having 1 to 18 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms), and [A] / [B] weight ratio 2/98 to 25/75
It is also advantageous to use a (meth) acrylic copolymer having a weight average molecular weight of 100,000 to 1,000,000 polymerized as (particularly 4/96 to 15/85). In the copolymerization, the (meth) acrylic acid ester [B] does not have to be a single monomer, and may be, for example, a mixture of esters having different alkyl groups as R ² . Further, a part of them may be replaced with styrene, acrylonitrile, or both of them. In addition, part of the acid group is Ca, Mg,
It may be a salt such as Zn.

Further, a copolymer of styrene and maleic anhydride is also preferable. Furthermore, derivatives of each of the above copolymers can also be used. Examples of such derivatives include those in which the carboxylic acid ester moiety in the copolymer is substituted with another monomer component such as styrene or acrylonitrile, and when a carboxylic acid component is present as the copolymer component, Examples thereof include those partially dehydrated, those esterified with a lower alcohol, and those amidated or maleimidated with an amine compound. The alkaline water-soluble polymer used in the present invention has a solubility in ammonia water of 5% by weight or more, preferably 10% by weight or more, and is not easily dissolved (including swelling) in neutral or acidic water. Is preferred.

Examples of the alkaline water-insoluble polymer substance include polymer polymers obtained by polymerizing one or more monomers having no water-soluble group, waxes, petroleum resins, natural resins, polymer fats and oils, and their modifications. I can list things. These are used in the state of an emulsion liquid emulsified and dispersed in water. Specific examples of the above polymer include polyethylene, ethylene / vinyl acetate copolymer, ethylene / vinyl acetate
Vinyl chloride copolymer, ethylene / vinyl acetate / acrylic acid ester copolymer, ethylene / acrylic acid ester copolymer, ethylene / methacrylic acid ester copolymer, acrylic acid ester copolymer, methacrylic acid ester copolymer, Acrylic ester / methacrylic ester copolymer, propylene / ethyl acrylic ester copolymer, vinyl acetate / acrylic ester copolymer, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polystyrene, acrylic ester / styrene Copolymer, polybutadiene, butadiene-styrene copolymer, EPD
Examples thereof include M polymers and EPDM / styrene copolymers. The wax has a melting point of 50-100.
A wax having a temperature of 60 ° C., particularly about 60 to 90 ° C., is advantageously used. Examples of preferable waxes include beeswax, wood wax, paraffin, crystallin wax, and oxidized wax. Further, as an example of the natural resin,
Examples thereof include natural rubber and rosin that has not been subjected to alkaline water solubilization treatment. In addition, fats and oils or modified products thereof,
Hardened oils, solid fatty acids and their metal salts can also be used. Further, a latex or emulsion in which an emulsifying dispersible resin such as polyurethane is emulsified and dispersed in water can also be used. It goes without saying that the polymer substances can be used alone or in combination. For a detailed description of the polymeric substances and emulsions and latexes that can be used in the present invention as described above, see "Introduction to Applications of Emulsions" (Masaaki Yura: Polymer Publishing Co., Ltd., April 1988). Published on 1st) and "polymer latex" (Soichi Muroi, Ikuo Morino: Polymer Publishing Co., Ltd.)
It was found on December 20, 1988).

In the present invention, the expression "water-insoluble" or "alkaline-water-insoluble" does not mean that it does not dissolve at all under a long-term or high-temperature condition, and a polymer substance is placed in contact with water or alkaline water. If no significant change is observed in about 1 day, or once a small amount (less than 5% by weight of the polymer to be observed,
After being dissolved, it means a state in which the progress of dissolution is hardly seen after the dissolution, and it can be said that it is sparingly soluble in water or sparingly soluble in alkaline water.

Next, a method for forming a coating layer on the surface of the granular fertilizer will be described. In the production of the slow-release fertilizer having the fertilizer elution control property of the present invention, the first coating layer containing an alkaline substance contains an alkaline substance, preferably together with a spreading material (such as a polymer), an aqueous solvent or an organic solvent, or It can be formed by preparing a coating solution dissolved or dispersed (including emulsified) in these mixed solvents, treating the surface of the granular fertilizer with this coating solution, and drying. Examples of the organic solvent include hydrocarbon solvents such as aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons (including halogenated hydrocarbon solvents), ether solvents, ketone solvents, alcohol solvents. , Amide solvents, and these may be used alone or in combination.

Specific examples of the hydrocarbon solvent include aromatic hydrocarbon solvents such as benzene, toluene, xylene, methylnaphthalene, chlorobenzene and dichlorobenzene,
Examples thereof include aliphatic hydrocarbon solvents such as petroleum ether, ligroin, n-hexane, methylene chloride, chloroform, dichloroethane and trichloroethane, and alicyclic hydrocarbon solvents such as cyclopentane and cyclohexane. Specific examples of the ether solvent include diethyl ether, tetrahydrofuran, dioxane and the like. Specific examples of the alcohol solvent include methanol, ethanol, propanol, butanol, isopropanol and the like. Specific examples of the ketone solvent include methyl ethyl ketone, acetone, methyl isobutyl ketone and the like. Specific examples of the amide solvent include N, N-dimethylformamide and N, N-dimethylacetamide.

The formation of the first coating layer on the granular fertilizer is usually carried out by the above-mentioned coating solution (alkaline substance, and preferably spreading material).
The coating liquid containing the above is applied to the surface of the granular fertilizer using a known particle coating device (eg, Nauta mixer, aeration type coating device, rotary agent coater), or while being applied thereto,
It is carried out by heating to a temperature of about -80 ° C to evaporate and remove the solvent and drying.

Then, a second coating layer is then formed on the surface of the granular fertilizer on which the first coating layer is formed. The formation of this second coating layer is an aqueous emulsion containing a mixture of an alkaline water-soluble polymeric substance and an alkaline water-insoluble polymeric substance (preferably a solvent consisting only of water, containing no organic solvent, and having a pH of 5-10, more preferably pH 7-1
The solvent is water adjusted to 0, especially pH 8 to 10. It is acceptable to use together an organic solvent having excellent miscibility with water as long as it is a small amount. ) Is deposited on the first coating layer using a similar coating device (using coating, spraying, etc.), and is dried by heating to obtain a solvent (water or a solvent containing water as a main component). ) Is removed. The second coating layer is
Even after the solvent is substantially evaporated, it is desirable to further perform heat treatment at a temperature of about 70 to 120 degrees for about 10 minutes to about 4 hours. Further, prior to this heat treatment, known anti-blocking materials such as fine particles of silicic acid and talc may be attached to the coated particles. Such heat treatment tends to increase the film strength of the second layer,
The coated granular fertilizer having such a reinforced second coating layer is preferable because the early elution of the fertilizer component after fertilization is effectively suppressed and the coating layer itself is less damaged. The amount of the alkaline water-soluble polymer substance in the second coating layer is usually in the range of 1 to 80% by weight as the ratio of the alkaline water-soluble polymer substance to the weight of the entire second coating layer, and preferably It is 2 to 50% by weight.

The composite coating layer structure on the surface of the granular fertilizer consisting of the first coating layer and the second coating layer described above has the other coating layers (the layer on the side contacting the fertilizer, the first coating layer). The provision of an intermediate layer between the second coating layer and the outermost layer outside the second coating layer is not excluded. That is, if necessary, another coating layer may be provided as long as it does not impair the function of the fertilizer elution control slow-release fertilizer of the present invention. For example, a layer of a water-insoluble polymer substance can be provided on the above composite layer. Also, depending on the purpose,
It is also effective to provide one or more sets of composite coating layers including the first coating layer and the second coating layer. The ratio of the amount of the coating material of the coating layer to the granular fertilizer is usually 0.5 to 30% by weight, preferably 1 to 20% by weight, particularly 2 to 15% by weight. Further, the thickness of the layer is preferably in the range of about 30 to 300 μm, particularly 50 to 200 μm as the thickness of the entire coating layer.

Next, the surface of any one of the granular fertilizer, which is another embodiment of the present invention, and the fertilizer of the coated fertilizer having a coating layer on the surface of the granular fertilizer is water-insoluble and alkali-water-soluble. A coated granular fertilizer coated with a water-insoluble polymer substance, characterized in that it is heated or dried while being treated with an aqueous solution of an alkali-water-soluble polymer substance in which the polymer substance is dissolved in alkaline water. The manufacturing method of is explained. The various fertilizer particles as exemplified above can be used as the granular fertilizer to which the coating layer forming treatment of the above aspect is applied. In addition, a coated granular fertilizer in which a coating layer made of an inorganic or organic substance is formed on the surface of these particles in advance can also be treated.

On the surface of the above-mentioned fertilizer (granular fertilizer or coated granular fertilizer), an aqueous polymer substance solution prepared by dissolving a water-insoluble and alkaline water-soluble polymer substance in alkaline water is first applied and then dried. To form a coating layer on the fertilizer particle surface. The coating layer is rendered water-insoluble after its completion. An example of an alkaline water-soluble polymer substance suitable for such a purpose is a salt of a water-insoluble polymer substance and ammonia or a water-soluble amine,
A substance that releases ammonia or water-soluble amine to become water-insoluble by heating and drying (for example, heating at 40 to 120 ° C. for 5 minutes to 2 hours) can be mentioned. Further, an alkali water-soluble resin such as a styrene-maleic anhydride resin or a rosin maleic acid modified product may be dissolved in an aqueous ammonia solution or an alkaline aqueous solution such as a water-soluble amine aqueous solution. When such a substance is used, the water resistance and mechanical strength of the surface of the coated particles,
It is preferable because resistance to deterioration is enhanced. In addition, the formed coating layer is usually a transparent and glossy film.

As an example of a salt of a water-insoluble polymer substance and ammonia or a water-soluble amine used in the above-mentioned production method, which is released by heating and drying to release ammonia or a water-soluble amine to become water-insoluble, marpozole. W
-60D, ((meth) acrylic acid / (meth) acrylic acid ester copolymer ammonium salt: a product of Matsumoto Yushi-Seiyaku Co., Ltd.), and Marposol W-247, Marposol W-247P (Matsumoto Yushi-Seiyaku Co., Ltd.) Product,
In each case, a commercially available product (aqueous solution) such as (meth) acrylic acid / (meth) acrylic acid ester / styrene copolymer ammonium salt) can be mentioned. As described above, such an alkaline water-soluble polymer substance can be advantageously used also in the above-mentioned coating of the granular fertilizer with the composite coating layer (formation of the second coating layer).

Further, acidic monomers such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid and maleic anhydride, basic monomers such as 2-aminoethyl vinyl ether and t-butylaminoethyl methacrylate, methyl acrylate, By homopolymerization or copolymerization of hydrophobic monomers such as ethyl acrylate, butyl acrylate, butyl methacrylate, styrene, etc., and monomers having hydrophilic groups such as hydroxypropyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, acrylamide, acrylonitrile, etc. The resulting water-insoluble polymer may be a salt formed by combining or combining ammonia or a water-soluble amine with a known method.

[0026]

【Example】

[Example 1] (1) Preparation of coating liquid for forming first coating layer 4.7 g of an ethylene vinyl acetate copolymer resin (manufactured by Nippon Unicar Co., Ltd., trade name: MB-850) was dissolved in toluene at 60 ° C. Then, 12 g of magnesium oxide (passed through a 200 mesh sieve) was mixed with this to prepare a coating liquid for forming a first coating layer containing a total amount of the resin and magnesium oxide of about 8% by weight. (2) Preparation of coating liquid for forming second coating layer Resin liquid of (meth) acrylic acid / (meth) acrylic acid ester / styrene copolymer ammonium salt diluted with water (Marposol W-247P, Matsumoto Yushi-Seiyaku Co., Ltd.) 5.1 g of solid product (commercial product) was mixed with 123 g of acrylic ester / styrene copolymer resin liquid (Hoechst Synthetic Co., Ltd., trade name: Movinyl 752) (solid content conversion), and water was further added. Was diluted with to prepare a coating liquid for forming a second coating layer containing 20% by weight of a resin.

(3) Formation of first coating layer A tilting plate type granulator with rotation control (stainless steel,
Diameter of 500 mm, depth of 100 mm) and particle size of about 2-4 m
2 kg of m granular advanced chemical fertilizer (manufactured by Ube Kasei Fertilizer Co., Ltd., trade name: Ube Kasei Ubehosuka No. 32) was charged, and the fertilizer particles were rotated at a rotation speed of 15 rpm while supplying hot air (drying air) at 80 ° C. And fertilizer at about 60 ℃
The coating solution for forming the first coating layer is gradually added dropwise over about 10 minutes, and the first coating layer has a coverage rate (solid content% by weight of the coating material relative to the fertilizer to be coated, the same applies hereinafter). To obtain 0.7% by weight of coated granular fertilizer. (4) Formation of second coating layer While rolling a ventilation rolling type coating device (manufactured by Freund Sangyo Co., Ltd., trade name: Hicoater HCT30N), drying air (70 to 90 ° C.) was supplied to this. The second coating was prepared by charging 0.8 kg of the coated granular fertilizer on which the first coating layer was formed (almost the same amount as the fertilizer component) and maintaining the fertilizer rolling layer temperature in the coating pan at about 45 ° C. The coating liquid for layer formation is sprayed at a supply rate of 13.5 g / min,
A composite coated granular fertilizer in which a composite coating layer of the first coating layer (coverage: 0.7% by weight) and the second coating layer (coverage: 15.2% by weight) was formed was obtained. Next, 1.6 g of hydrous fine powder silicic acid (manufactured by Tokuyama Corp., trade name: Tokuseal) is attached to the surface of this composite coated granular fertilizer, which is then transferred to a stainless steel dish (vat) and ventilated constant temperature drying. Machine (Advantech Toyo Co., Ltd., trade name; FC-610)
Was used for heat treatment at 100 ° C. for 20 minutes.

[Example 2] (1) Preparation of coating liquid for forming first coating layer The coating liquid for forming first coating layer of Example 1 was used (2) Preparation of coating liquid for forming second coating layer With water A diluted (meth) acrylic acid / (meth) acrylic acid ester copolymer ammonium salt resin solution (Marposol W-60D, trade name of Matsumoto Yushi-Seiyaku Co., Ltd.)
Taking 5.1 g as a solid content, an acrylic acid ester / styrene copolymer resin liquid (the above-mentioned Movinyl 75
2) 123 g (as solid content) was mixed and further diluted with water to prepare a second coating layer forming coating liquid containing 20% by weight of resin. (3) Formation of composite coating layer The first coating layer (coverage: 0.7% by weight) was prepared in the same manner as in Example 1 except that the above coating liquid was used as the coating liquid for forming the second coating layer. A composite coated granular fertilizer in which the composite coating layer of the second coating layer (coverage: 15.1% by weight) was formed was obtained. After attaching 1.6 g of hydrous fine powder silicic acid to the surface of this composite coated granular fertilizer, it was transferred to a stainless steel dish and subjected to heat treatment at 100 ° C. for 20 minutes using a ventilation constant temperature dryer. did.

[Example 3] (1) Preparation of coating liquid for forming first coating layer [0029] The same as the method described in (1) of Example 1 except that the mixing amount of magnesium oxide was changed to 4.8 g. A coating liquid for forming the first coating layer was prepared. (2) Preparation of coating liquid for forming second coating layer A resin liquid (Marposol W-60D) of a (meth) acrylic acid / (meth) acrylic acid ester copolymer ammonium salt diluted with water was added as a solid content of 6 A second coating containing 20% by weight of resin was obtained by mixing 0.7 g of the acrylic acid ester / styrene copolymer resin liquid (Movinyl 752 above) (161 g (solid content conversion)) and further diluting with water. A layer forming coating solution was prepared. (3) Formation of Composite Coating Layer The first coating layer (coverage ratio: 0.4) was prepared in the same manner as in Example 1 except that the above coating liquid was used as the coating liquid for forming the first and second coating layers. Wt%) and the second coating layer (coverage: 1
A composite coated granular fertilizer having a composite coating layer (9.9% by weight) was obtained. After attaching 1.6 g of hydrous fine powder silicic acid to the surface of this composite coated granular fertilizer, it was transferred to a stainless steel dish and subjected to heat treatment at 100 ° C. for 20 minutes using a ventilation constant temperature dryer. .

[Example 4] (1) Preparation of coating liquid for forming first coating layer Using coating liquid for forming first coating layer of Example 1 (2) Preparation of coating liquid for forming second coating layer With water 4.1 g of a diluted resin solution of (meth) acrylic acid / (meth) acrylic acid ester copolymer ammonium salt (Marposol.W-60D) was taken as a solid content, and this was used as an acrylic acid ester copolymer resin solution ( A coating liquid for forming a second coating layer containing 20% by weight of a resin component was prepared by mixing with 99 g (trade name: Movinyl 727) manufactured by Hoechst Synthetic Co., Ltd. (in terms of solid content) and further diluting with water. (3) Preparation of coating liquid for forming third coating layer Acrylic ester copolymer resin liquid (Movinyl 900
26 g (trade name of Hoechst Synthetic Co., Ltd.) (weight in terms of solid content) was diluted with water to prepare a coating liquid for forming a third coating layer containing 20% by weight of a resin component. (4) Formation of composite coating layer By the method described in Example 1, the first coating layer (coverage: 0.7
%) And a second coating layer (coverage: 12.2% by weight), and then spraying the above coating liquid for forming a third coating layer under the same spraying conditions following the step of forming the second coating layer. Then, a total of three coating layers (total coverage: 15.9) on the surface of the fertilizer particles.
To obtain a coated granular fertilizer in which (% by weight) is formed. When forming the second and third coating layers, the fertilizer rolling layer temperature should be 40 ° C.
And the coating liquid supply rate was set to about 11 g / min. After adhering 1.6 g of hydrous fine powder silicic acid on the surface of the composite coated granular fertilizer obtained above, it was transferred to a stainless steel dish and heated at 90 ° C. for 1 hour using a ventilation constant temperature dryer. Treated.

[Example 5] (1) Preparation of coating liquid for forming first coating layer The coating liquid for forming first coating layer of Example 1 was used (2) Preparation of coating liquid for forming second coating layer With water 4.1 g of the diluted (meth) acrylic acid / (meth) acrylic acid ester copolymer ammonium salt resin solution (Marposol W-60D) was taken as a solid content, and this was taken as an acrylic acid ester / styrene copolymer resin solution ( Polysol AP-4710, a product of Showa Highpolymer Co., Ltd.) 99 g
(Converted to solid content) and further diluted with water to prepare a second coating layer forming coating liquid containing 20% by weight of resin content. (3) Preparation of Third Coating Layer Forming Coating Liquid The third coating layer forming coating liquid of Example 4 was used. (4) Formation of composite coating layer By the same operation as in Example 4 except that the above coating liquid was used as the coating liquid for forming the second coating layer, a total of three composite coating layers (total) were formed on the surface of the fertilizer particles. Coverage: 15.7% by weight)
A composite coated granular fertilizer in which the slag was formed was obtained. After 1.6 g of hydrous fine powder silicic acid was attached to the surface of this composite coated granular fertilizer, it was transferred to a stainless steel dish and subjected to heat treatment at 100 ° C. for 20 minutes using a ventilation constant temperature dryer.

Example 6 (1) Preparation of coating liquid for forming first coating layer 18 g of dipotassium phosphate (first-grade reagent) was dissolved in water, and the first coating containing dipotassium phosphate in an amount of about 25% by weight. A layer forming coating solution was prepared. (2) Preparation of coating liquid for forming second coating layer Use coating liquid for forming second coating layer of Example 2 (3) Formation of composite coating layer Use the above coating liquid as coating liquid for forming first coating layer The same procedure as in Example 2 except that the composite coating granules in which the composite coating layer of the first coating layer (coverage: 2% by weight) and the second coating layer (coverage: 15% by weight) were formed. I got fertilizer. 1.6 g of hydrous fine powder silicic acid on the surface of this composite coated granular fertilizer
After adhering, was transferred to a stainless steel dish and heat-treated at 80 ° C. for 1 hour using a ventilation type constant temperature dryer.

[Dissolution test] (1) The composite coated granular fertilizers obtained in Examples 1 to 6 were used.
After leaving it in a constant temperature bath for 36 days at ℃ (this condition is equivalent to the condition of normal fertilizer storage for 2 years), take it out and put it in the "Ministry of Agriculture, Forestry and Fisheries National Institute of Agricultural Technology and Environment 12 Fertilizer analysis method issued on 25th of March, 5.3
The elution rate of the nitrogen component was measured according to the measuring method defined in "1. The result is shown in FIG. (2) Even though water was used as the solvent for the coating liquid for forming the second coating layer, by changing the material of the coating layer, the storability was high and the desired elution start time and elution pattern were arbitrarily obtained. It can be seen that a coated fertilizer showing is obtained.

[Example 7] (1) Preparation of coating liquid for forming coating layer Resin liquid of (meth) acrylic acid / (meth) acrylic acid ester / styrene copolymer ammonium salt diluted with water (Marposol / W- 247P, trade name of Matsumoto Yushi-Seiyaku Co., Ltd.) was taken as a solid content in an amount of 128 g and diluted with water to prepare a coating layer forming coating solution containing 17% by weight of a resin content. (2) Formation of coating layer Using a ventilation rolling type coating device (manufactured by Freund Sangyo Co., Ltd., trade name: Hicoater HCT30N), according to the method described in (4) of Example 1, a particle diameter of about 2 to 4 mm The coating solution is sprayed onto the surface of the granular advanced chemical fertilizer (Ubekasei Ubephosca No. 32) at a supply rate of about 13 g / min to form a single coating layer (coverage: 15.2% by weight). The coated granular fertilizer was obtained. After attaching 1.6 g of water-containing fine powder silicic acid to the surface of this composite coated granular fertilizer, it was transferred to a stainless steel dish, and a ventilation type constant temperature dryer 100 ° C was used.
Was heat-treated for 10 minutes.

[Example 8] (1) Preparation of coating liquid for forming coating layer (meth) acrylic acid / (meth) acrylic acid ester / styrene copolymer ammonium salt resin liquid (marposol /
W-247P) was replaced with a (meth) acrylic acid / (meth) acrylic acid ester copolymer ammonium salt resin solution (Marposol W-60D) in the same manner as in (7) of Example 7 to obtain a resin component. A coating liquid for forming a coating layer containing 17% by weight of was prepared. (2) Formation of coating layer Using the coating liquid for forming the coating layer described above, a single coating layer (coverage: 15.0% by weight) was obtained according to the procedure described in (2) of Example 7.
The coated granular fertilizer in which the was formed was obtained. After adhering 1.6 g of hydrous fine powder silicic acid on the surface of this composite coated granular fertilizer,
Transfer to a stainless steel dish and let the ventilation type constant temperature dryer 1
Heat treatment was performed at 00 ° C. for 10 minutes.

[Dissolution Test] (1) The dissolution characteristics of the coated granular fertilizers obtained in Examples 7 to 8 were measured according to the dissolution test method described above to measure the dissolution rate of nitrogen components. The result is shown in FIG. (2) It is found that a coated fertilizer excellent in storage stability can be obtained even though water is used as the solvent of the coating liquid for forming the coating layer.

[0037]

According to the method for producing a coated granular fertilizer of the present invention,
It becomes possible to produce a coated granular slow-release fertilizer having a composite coating layer having excellent fertilizer elution control properties and / or a slow-release coated granular fertilizer having excellent storage properties, while mainly using water as a solvent. Therefore, the method for producing a coated granular fertilizer of the present invention is an industrially advantageous method for producing a coated granular fertilizer.

[Brief description of drawings]

FIG. 1 is a diagram showing an elution pattern of nitrogen components after storage under severe conditions of a composite coated granular fertilizer produced according to the production method of the present invention.

FIG. 2 is a diagram showing an elution pattern of nitrogen components of a coated granular fertilizer produced according to the production method of the present invention after storage under severe conditions.

Claims (6)

[Claims] 1. A first coating layer containing an alkaline substance is formed on the surface of a granular fertilizer, and then an aqueous emulsion containing a mixture of an alkaline water-soluble polymeric substance and an alkaline water-insoluble polymeric substance is coated on the outside thereof. A method for producing a coated granular fertilizer, which comprises drying to form a second coating layer. 2. The method for producing a coated granular fertilizer according to claim 1, comprising a step of subjecting the formed second coating layer to a heat treatment. 3. The method for producing a coated granular fertilizer according to claim 1, wherein the pH of the aqueous emulsion is between 5 and 10. 4. The method for producing a coated granular fertilizer according to claim 1, wherein the solvent of the aqueous emulsion comprises substantially only water. 5. The water-insoluble and alkaline-water-soluble polymer substance is dissolved in alkaline water on the surface of the granular fertilizer or one of the coated fertilizers having a coating layer on the surface of the granular fertilizer. A method for producing a coated granular fertilizer coated with a water-insoluble polymer substance, which comprises heating or drying while treating with or after treatment with the aqueous polymer substance solution. 6. The polymer substance is a salt of a water-insoluble polymer substance and ammonia or a water-soluble amine, and the polymer substance returns to water-insoluble by releasing ammonia or the water-soluble amine by subsequent heating and drying. Claim 5 which is
The method for producing the coated granular fertilizer according to 1.