JP2000143406A - Production of controlled-release coated agrochemical granule - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of suppressing the leakage of an agrochemical component of a controlled release agrochemical granule of the release-controlled period, and further preventing the releasing function from being changed with time by preservation. SOLUTION: This production method of a covered agrochemical granule by spraying a resin solution obtained by dissolving a thermoplastic resin in a solvent, on the surface of an agrochemical particle containing one or more kinds of agrochemical components to form a coat on the surface of the particle, uses particles having 0.3-3.0 mm mean diameter and a nozzle capable of forming liquid drops having mean diameter within the range of 80-300 μm when pure water at 21 deg.C is sprayed. The coated agrochemical granule releasing the agrochemical after the limited time is excellent in the following points compared with conventional product: (1) the leak is little at the release-controlled period, and thereby the chemical injury is suppressed to the utmost; (2) the change with time under preservation is little, and thereby the stabilized quality is kept; and (3) the leakage at the release-controlling period is little, and thereby the change with time under preservation is small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time-release type coated pesticide granule in which the surface of pesticide particles containing a pesticide component (hereinafter referred to as "core material") is coated with a coating containing a thermoplastic resin as an active ingredient. And a method for producing the same.

[0002]

2. Description of the Related Art In recent years, the problem of environmental destruction caused by pesticides has been highlighted, and pesticides are required to have high efficacy and high selective toxicity. On the other hand, in the recent agricultural environment in which the farming population is decreasing and the farmers are aging, labor saving and efficiency improvement of the pesticide spraying work are required, and the sustained release of the pesticide components and the extended sustained release period are required. For the purpose, coated pesticide granules in which pesticide particles are coated with a coating material have been developed. Due to its release function, coated pesticide granules can release pesticide components immediately after application (hereinafter referred to as “linear coated pesticides”), and the release of pesticide components for a certain period after application is suppressed. Coated pesticide particles having a timed release type sustained release function comprising a release suppression period (hereinafter referred to as "d1") and a period in which the release of the pesticide component continues after a certain period (hereinafter referred to as "d2"). Agents (hereinafter referred to as "time-release coated pesticides"). Among them, the time-release coated pesticide has d1, so that when it is sprayed at the time of sowing or transplanting of seedlings, even if it contains an agrochemical component that is likely to cause phytotoxicity, seeding or seedling of the seedlings in this field is not possible. Since it can be applied simultaneously with transplantation, it is a promising pesticide formulation in terms of labor saving of pesticide spraying work.

[0003]

As a preferable coating material used for the coating of the time-release type pesticide, a thermoplastic resin is known, and particularly, an olefin polymer having a small moisture permeability is known as a preferable material. I have. Time-release coated pesticides containing a thermoplastic resin as an active ingredient of a coating are usually formed by dissolving or dispersing a coating material such as a thermoplastic resin in a solvent and spraying the core material in a rolling or flowing state. Have been obtained. Among the conventional time-release type coated pesticides thus obtained, the control of the release of the pesticide component in d1 is insufficient, and the pesticide component leaks out during the period. When the coated pesticide is applied at the same time as sowing or transplanting, for example, most of the necessary chemicals during the entire cultivation period, problems such as phytotoxicity caused by pesticide components leaked slightly during d1 may occur. Yes, and the release function immediately after production (d1 and d
2) and the release function after storage for a certain period of time, that is, the release function may change over time.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to develop a technique for suppressing the leakage of pesticide components in d1 of a time-release coated pesticide and a technique for preventing the release function from changing over time due to storage. went. As a result, a resin solution in which a thermoplastic resin is dissolved in a solvent is sprayed on the surface of pesticide particles containing one or more pesticide components, and a method for producing a coated pesticide granule in which a resin film is formed on the surface of the particles. ,
The average particle size of the particles is 0.3 to 3.0 mm,
The average particle size of droplets when pure water is sprayed is 80 to 30
In the case of a time-release type coated pesticide obtained by a production method using a nozzle having a range of 0 μm, it has been found that leakage of the pesticide component in d1 can be suppressed, and further, the thermoplastic resin used in the film forming step is used. The melting point of
If the _m ° C., a heat treatment at (T _m -5) After forming a resin film at a surface temperature of ° C. or less pesticide particles, (T _m -60) ℃ or higher (T _m -5) below ° C. Temperature It has been found that a time-release-type coated pesticide obtained by the production method can suppress the time-dependent change of the release function due to storage, and based on this finding, completed the present invention.

The present invention has the following configurations (1) and (2). (1) A resin solution obtained by dissolving a thermoplastic resin in a solvent is
A method for producing a coated pesticide granule that sprays on the surface of pesticide particles containing one or more kinds of pesticide components and forms a film on the surface of the particles, wherein the average particle size of the particles is 0.3 to 3.0 mm; A method for producing a time-release coated pesticide granule, wherein a nozzle having an average particle diameter of droplets in a range of 80 to 300 μm when sprayed with pure water at 21 ° C. is used. (2) A resin solution obtained by dissolving a thermoplastic resin in a solvent is
When the melting point of the thermoplastic resin used is T _m ° C in the film-forming step of spraying the surface of the pesticide particles containing one or more kinds of pesticide components and forming a resin film on the surface of the particles, (T _m −
5) A time-release type coated pesticide characterized in that a resin film is formed at a surface temperature of the pesticide particles of not more than ° C and then heat-treated at a temperature of ( _Tm- 60) ° C or more and less than ( _Tm- 5) ° C. Manufacturing method of granules.

Hereinafter, the present invention will be described in detail. The first invention of the present invention is to spray a resin solution obtained by dissolving a thermoplastic resin in a solvent under hot air on the surface of pesticide particles containing one or more pesticide components, and to form a resin coating on the surface of the particles. In the film forming step of forming, the average particle diameter of the particles is 0.3 to 3.0 m.
m, and a nozzle having a mean particle size of droplets in the range of 80 to 300 μm when sprayed with pure water at 21 ° C. is used to produce a time-release type coated pesticide granule.

The pesticidal components used in the present invention include those having insecticidal, bactericidal, weeding and plant growth regulation, as well as miticidal and nematicidal effects, repellents, and attractants. If there is, it can be used without limitation. Preferably, the powder is solid at room temperature, but may be liquid at room temperature. In the present invention, the pesticide component used may be water-soluble, hardly water-soluble, or water-insoluble, and is not particularly limited. Specific examples of the pesticidal components that can be used in the present invention are shown below, but these are merely illustrative and not restrictive.
The pesticide component may be one kind or two or more kinds of composite ingredients.

For example, 1- (6-chloro-3-pyridylmethyl) -N-nitroimidazolidine-2-ylideneamine, O, O-diethyl-S-2- (ethylthio) ethyl phosphorodithioate, 1,3-bis (Carbamoylthio) -2- (N, N-dimethylamino) propane hydrochloride, 2,3-dihydro-2,2-dimethyl-7-benzo [b] furanyl = N-dibutylaminothio-N-methylcarbamate , (2-isopropyl-4-methylpyrimidyl-6) -diethylthiophosphate,

5-dimethylamino-1,2,3-trithiane oxalate, O, O-dipropyl-O-4-methylthiophenyl phosphate, ethyl = N- [2,3-
Dihydro-2,2-dimethylbenzofuran-7-yloxycarbonyl (methyl) aminothio] -N-isopropyl-β-alaninate, 1-naphthyl-N-methylcarbamate, 2-isopropoxyphenyl-N-methylcarbamate, diisopropyl- 1,3-dithiolane-
2-ylidene-malonate, 5-methyl-1,2,4-
Triazolo [3,4-b] benzothiazole, 1,2,2
Sodium salt of 5,6-tetrahydropyrrolo [3,2,1-ij] quinolin-4-one, 3-allyloxy-1,2-benzoisothiazole-1,1-dioxide, 2,4-dichlorophenoxyacetic acid or Dimethylamine salt, ethyl ester.

The sodium salt of 2-methyl-4-chlorophenoxyacetic acid or ethyl, butyl ester. Sodium salt or ethyl ester of 2-methyl-4-chlorophenoxybutyric acid. α- (2-naphthoxy) propionanilide, S-1-methyl-1-phenylethyl piperidine-1-carbothioate, S- (4-chlorobenzyl) -N, N-diethylthiocarbamate, 5-tertiary Butyl-3- (2,4-dichloro-5-isopropoxyphenyl) -1,3,4-oxadiazoline-2
-One, 2- [4- (2,4-dichlorobenzoyl)-
1,3-dimethylpyrazol-5-yloxy] acetophenone, 4- (2,4-dichlorobenzoyl) -1,
3-dimethyl-5-pyrazolyl-p-toluenesulfonate, 3-isopropyl-2,1,3-benzo-thiadiazinone- (4) -2,2-dioxide or its sodium salt, 2-chloro-4-ethylamino- 6-isopropylamino-s-triazine,

2-Methylthio-4-ethylamino-6
(1,2-dimethylpropylamino) -s-triazine, 2-methylthio-4,6-bis (ethylamino)-
s-triazine, 2-methylthio-4,6-bis (isopropylamino) -s-triazine, 1- (α, α-dimethylbenzyl) -3- (paratolyl) urea, methyl =
α- (4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl) -o-toluate, 2-benzothiazol-2-yloxy-N-methylacetanilide, 1- (2-chloroimidazo [1,2-a ] Pyridin-3-ylsulfonyl) -3- (4,6-dimethoxypyrimidin-2-ylurea, S-benzyl = 1,2-dimethylpropyl (ethyl) thiocarbamate, 2-chloro-N- (3- (Methoxy-2-thenyl) -2 ′, 6′-dimethylacetanilide, etc.
After contact with the plant as the pesticide component in the present invention,
It also includes a substance that induces phytoalexin, a low-molecular-weight antibacterial substance that is synthesized by plants and accumulates in plants.

The composition of the core material used in the present invention is not particularly limited as long as it contains one or more agricultural chemical components. It may be granulated with pesticide ingredients alone, granulated using a carrier such as clay, kaolin, talc, bentonite, calcium carbonate, or a binder such as polyvinyl alcohol, sodium carboxymethylcellulose, starch, etc. It does not matter. Surfactants may be added as necessary. Specifically, anionic surfactants such as higher fatty acid salts, cationic surfactants such as higher alkyl / amine salts, and nonionic surfactants such as fatty acid esters of polyols. Agents can be exemplified. Further, depending on the pesticide component, a safener or stabilizer may be used in combination.

As a method of granulating the core material, an extrusion granulation method,
Fluidized bed granulation, tumbling granulation, compression granulation, coating granulation, adsorption granulation, and the like can be used. In the present invention, any of these granulation methods may be used, but the extrusion granulation method is the simplest.

The average particle size of the core material used in the present invention is 0.3 to 0.3.
3 mm, and 0.3 to 3 mm by using a sieve.
An arbitrary average particle size can be selected within the range. If the average particle size of the core material is less than 0.3 mm, it becomes difficult to coat the core material, and handling becomes poor because the average particle size is too small. When it exceeds 3 mm, when applying the obtained pesticide granule to the seedling cultivation soil or the field, the number of particles to be sprayed per unit area decreases, and it becomes difficult to uniformly spray the pesticide component, and as a result, the concentration gradient is reduced. The resulting medicinal effect becomes insufficient. Preferably the average particle size is 0.7 to 2.5 mm
It is desirable that the average particle diameters be uniform in terms of coating processing and further eliminating the concentration gradient of the agricultural chemical component to be sprayed.

The shape of the core material is preferably spherical in order to exhibit a time-release type sustained release function. Specifically, using a circularity coefficient which is a measure for knowing the degree of circularity of a particle, it was obtained by the formula {(4π × projected area of particle) / (length of contour of particle projected view) ² }. The value is preferably 0.7 or more, more preferably 0.75 or more, and still more preferably 0.8 or more. The maximum value of the circularity coefficient is 1
In the case where the core material particle is a perfect circle as it approaches 1,
And the circularity coefficient decreases as the particle shape collapses from a perfect circle. When the coefficient of the core material having a coefficient of less than 0.7 increases, the release of the coated pesticide granules obtained using the same at d1 becomes insufficient, and the pesticide components in the coating tend to leak out. It is preferable that all of the core materials of the present invention are 0.7 or more. However, as long as the effects of the present invention are not significantly impaired, there may be a small amount of materials having a value less than the lower limit. The circularity coefficient can be measured using a commercially available measuring instrument such as PIAS-IV (manufactured by Pierce Co., Ltd.). In the case where the coated pesticide granules using the granular core material have a timed release type sustained release function, leakage of the pesticide components in d1 can be significantly suppressed, which is particularly effective.

The thermoplastic resin used in the present invention includes, for example, olefin polymers, vinylidene chloride polymers,
Examples include diene polymers, waxes, polyesters, petroleum resins, natural resins, fats and oils, and modified products thereof. The coating of the time-release coated pesticide of the present invention may be at least one selected from thermoplastic resins. Can be used.

Examples of the olefin polymer include polyethylene, polypropylene, ethylene-propylene copolymer,
Ethylene-carbon monoxide copolymer, polybutene, butene-
Ethylene copolymer, butene-propylene copolymer, polystyrene, ethylene-vinyl acetate copolymer, ethylene-
Vinyl acetate-carbon monoxide copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid ester copolymer, etc. can be exemplified, and as the vinylidene chloride-based polymer, vinylidene chloride-vinyl chloride copolymer is exemplified. Examples of the diene polymer include butadiene polymer, isoprene polymer, chloroprene polymer, butadiene-styrene copolymer, EPDM polymer, and styrene-isoprene copolymer.Examples of waxes include waxes. , Wood wax, paraffin, etc., as examples of polyester, polylactic acid, polycaprolactone, as examples of natural resins, as natural rubber, rosin, etc., as oils and fats and their modified products, cured products, solid fatty acids and Examples thereof include metal salts and the like.

In order to achieve the time-release type sustained release function, it is necessary to completely cover the surface of the core material with a thermoplastic resin and form a film capable of suppressing moisture permeability.
That is, it is important to form a film without pinholes or cracks. When a long d1 is required, it is effective to coat the surface of the core material with a resin film having low moisture permeability. By coating the resin film with small moisture permeability,
The moisture existing outside can be gradually penetrated into the core material inside the film over time.

For this purpose, it is effective to use an olefin polymer or a vinylidene chloride polymer. In particular, polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-carbon monoxide copolymer are the most preferable resin materials in view of the lengths of d1 and d2, and further, the width of the selectable range of d1 / d2 ratio. It can be mentioned as. When these materials are used, if a film without pinholes or cracks is formed, the amount of permeation of moisture is extremely small.

Further, in the present invention, a filler or a surfactant for imparting hydrophilicity may be added to the coating as long as the effects of the present invention are not impaired. Examples of fillers include nonionic surfactants represented by talc, clay, kaolin, bentonite, sulfur, muscovite, phlogopite, mica-like iron oxide, metal oxides, siliceous materials, glass and fatty acid esters of al polyols. Can be mentioned. Potassium earth metal carbonates, sulfates, starch and the like can be mentioned, as the surfactant,

The resin solution to be sprayed is obtained by dissolving a thermoplastic resin in a solvent. The solvent may be appropriately selected depending on the solubility of the thermoplastic resin, the safety during the coating operation, and the like, and is not particularly limited. For example, in the case of polyethylene, a chlorine-based solvent such as tetrachloroethylene and a hydrocarbon-based solvent such as toluene are preferable.

The method for dissolving the thermoplastic resin is not particularly limited, but the temperature of the solvent at the time of dissolution depends on the boiling point of the solvent, T _b.
It is preferably in the temperature range when (T _b -60) less ° C. or higher T _b ° C. which was. The higher the temperature of the solvent is, the shorter the dissolution time of the thermoplastic resin is. However, _{if the} temperature exceeds T _b ° C, the solvent evaporates during the dissolution, and the concentration of the resin solution changes greatly.
In order to prevent this concentration change, additional equipment such as a solvent condenser is required. (T _b -60) becomes less soluble below the ℃ resin requires a long time to dissolve the resin.

The concentration of the resin in the resin solution (in the case of using an additive such as a filler, the concentration of the coating material in which the resin and the additive are added) is not particularly limited, but is preferably 1-2.
0% by weight, more preferably 3 to 10% by weight.
Range. On film formation, if the concentration is low, a dense film is formed, but a large amount of solvent is required to dissolve a predetermined amount of resin, and if the concentration is high, the total amount of the resin solution is small, so that the coating time is short. , But there is a tendency that blocking between particles tends to occur during the coating operation.
The melting point T _m of a thermoplastic resin can be easily measured by known methods such as DSC.

In the present invention, the coating film is formed by spraying a resin solution obtained by dissolving a coating material containing a thermoplastic resin as an active ingredient with an organic solvent onto a rolling or flowing core material, while applying a high-speed hot air flow. It is achieved by removing the solvent on the surface of the core material by spraying it on the core material and drying it to form a film on the surface. An example of a coating apparatus that can be used in the production method of the present invention will be described with reference to the accompanying drawings. However, the production method of the present invention is most preferably performed using the spouted bed shown in FIG. In the method, when a coating material that is insoluble in an organic solvent such as an inorganic filler is used by dispersing it in a resin solution, the coating material that is insoluble in an organic solvent is dispersed in the resin solution (hereinafter, a resin solution insoluble in an organic solvent). In order to uniformly disperse such a coating material dispersed in a resin solution in a resin solution), it is particularly necessary to vigorously stir the coating material solution. This spouted bed transports a resin solution (or a coating material dissolving solution) to the core material 3 in a spouted state via a pipe 5, sprays the solution by a spray nozzle 2, and sprays the surface onto the surface of the core material 3, and Simultaneously with the coating, high-speed hot air is caused to flow into the jet tower 1 from below into the guide tube 6, and the high-speed hot air flow causes the solvent in the resin solution (or the coating material dissolving solution) adhering to the core material surface to flow. Is instantaneously evaporated to dryness. The spraying time varies depending on the resin concentration of the resin solution (or the solution of the coating material), the spray speed of the solution, the coverage, and the like, and these should be appropriately selected according to the purpose.

The nozzle used in the present invention has a temperature of 21 ° C.
Is a nozzle having an average droplet diameter of 80 to 300 μm when measured at a position of 0.3 m from the tip of the nozzle when pure water is sprayed. Measurement conditions were as follows: temperature 20 ± 5 ° C, humidity 6
0 ± 10%, in a windless atmosphere, the spray pressure is 0.294 MPa · G for a one-fluid nozzle, the water pressure is 0.196 MPa · G for a two-fluid nozzle, and the air pressure is 0.098 ０．２0.294 MPa · G. As a measuring method, a laser method utilizing diffraction of laser light, and a liquid immersion method in which a spray liquid is trapped and measured with silicon oil are used. The pure water-based droplet diameter is preferably in the range of 80 to 300 μm, and more preferably 100 to 250 μm.
m. When a nozzle having a droplet diameter based on pure water of less than 80 μm is used, the droplet of the resin solution when the resin solution is actually sprayed is dried before reaching the surface of the core material, and a film cannot be formed. Or, even if it adheres to the surface of the core material, it is too fine and tends to peel off from the surface of the core material due to insufficient adhesive force. Even if blocking is likely to occur due to adhesion between the particles and blocking does not occur, the coating is damaged each time due to repeated adhesion and desorption of the particles, which causes leakage of the pesticide component in d1. .

The nozzle used in the present invention may be either a one-fluid nozzle or a two-fluid nozzle, but the spray pattern is preferably a circular full-surface type or an annular type. The spray amount and spray angle at that time are specified by the type of spray nozzle, especially the outlet diameter (minimum gap) and the spray (or spray) pressure. Can be. The outlet diameter of the nozzle is preferably φ0.1 to 3.0 mm, more preferably φ0.3 to 2.0 mm. In other words, when the diameter is smaller than 0.1 mm, the spray droplets become too fine, which is not preferable. Also, φ0.3mm
When the number of droplets exceeds the above range, the droplet diameter becomes large and the number of droplets decreases with the same spray amount, so that it is difficult to form a uniform film. Furthermore, particles tend to easily block each other during spraying, which is not preferable.

The spray pressure applied to the nozzle during the actual coating operation is preferably 0.1 to 3 MPa, and the spray angle is 50 to 50 MPa.
Preferably it is 100 °. The spray may be directed upward, downward, or sideways, but it is preferable to coat the nozzle with the nozzle outlet facing directly upward. Further, one or more sprays of the coating apparatus may be used.

As a coating apparatus which can be used in the present invention other than the spouted bed shown in FIG. 1, specifically, a fluidized bed type or spouted bed type coating apparatus is disclosed in Japanese Patent Publication No. Sho 42-24.
No. 281 and Japanese Patent Publication No. 42-24282, a device for forming a fountain type fluidized bed of particles by a gas body and spraying a coating agent onto a particle dispersion layer formed at the center can be mentioned. Japanese Patent Application Laid-open No. Hei 7
No.-31914, JP-A-7-195007, etc., the powder is transferred upward by a lifter provided on the inner periphery of the drum by rotation of the drum and then dropped, and the surface of the falling powder is coated with a coating agent. Can be mentioned.

The time-release coated pesticide according to the present invention has d1 and d2, and the ratio of d1 / d2 is 0.2.
These are the coated pesticide granules described above. d1 is the number of days required from the application of the pesticide granule to the release of 10% by weight of the pesticide in the pesticide particles, and d2 is from 10% by weight to 9%.
This is the number of days required to reach 0% by weight.

[0030] The coating composition of the time-release coated pesticide produced by the production method of the present invention is not particularly limited. Specifically, the high water-absorbing swelling disclosed in JP-A-6-9303 is disclosed. A multilayer coating comprising a substance layer and an olefin polymer layer; a multilayer coating comprising a mixed substance layer of an alkali substance layer and a condensation polymer and an alkali water-soluble polymer disclosed in JP-A-6-72805; 6-80514
The multi-layer coating composed of a high water-absorbing swellable substance layer and a condensation-type polymer layer disclosed in Japanese Patent Application Laid-Open Publication No. H11-209,086. Each of these is composed of two coating layers, and it is desirable that the coating be a single layer in view of the complexity of the coating operation and the cost such as capital investment for manufacturing equipment.

Specific examples of coated pesticide granules capable of achieving a time-release type sustained release function with a single layer film include at least one or more pesticides and at least one pesticide disclosed in JP-A-9-77608. A coated pesticide granule in which the surface of the pesticide particles composed of the above water-swelling substance is coated with a coating containing a resin as a main component can be given.

According to a second aspect of the present invention, a resin solution obtained by dissolving a thermoplastic resin in a solvent is sprayed on the surface of pesticide particles containing one or more pesticide components, and a resin film is formed on the surface of the particles. When the melting point of the thermoplastic resin used is T _m ° C in the film forming step to be performed, the resin film is formed at the surface temperature of the pesticide particles of (T _m -5) ° C or lower, and then (T _m -60) ° C
The above is a method for producing a time-release type coated pesticide granule which is heat-treated at a temperature lower than ( _Tm- 5) C. The effects of the present invention can be obtained by any apparatus and method as long as the heat treatment is performed subsequent to the spray coating, and is not particularly limited.

In the production method of the present invention, the core material surface temperature during spraying is preferably (T _m -5) ° C. or lower, more preferably 30 ° C. or higher (T _m -10) ° C. or lower. 3
When the temperature is lower than 0 ° C., it takes a long time to dry the film, and (T
If the temperature is higher than _m− 10) ° C., the coating is softened and defects are likely to occur. In the case of a coating composed of a plurality of thermoplastic resins, the melting point of the resin having a large content is used as the T _m ° C of the thermoplastic resin, and when the weight ratio is the same, the resin having the higher melting point is used. And used as _Tm ° C of the thermoplastic resin.

The temperature condition of the heat treatment after the formation of the film is preferably a temperature of (T _m -60) ° C. or more and less than (T _m -5) ° C. If the upper limit is exceeded, the coating will soften, making it difficult to obtain a uniform coating, and in some cases, the coating may be fused and blocking may occur. When it is less than the lower limit, it may not be possible to suppress the temporal change of the release function.

The heat treatment method is not particularly limited.
Methods such as infrared irradiation and microwaves can be cited, and among them, it is easiest to perform hot air flow after coating. The core material formed under the conditions of flow, rolling, standing, etc. may be subjected to heat treatment by ventilation, and the heat treatment time is determined by the thickness of the film, the concentration of the resin solution, and the amount of the time-release coated pesticide to be treated. For example, it is not uniform, but is preferably 0.05 to 2 hours.

When a highly hydrophobic resin such as an olefin polymer is used for the coating of the time-release type coated pesticide of the present invention, the water repellency of the coating itself becomes strong, for example, in a paddy field under flooded conditions. When applied, the applied time-release-type coated pesticide emerges, adversely affecting the onset of drug efficacy. To avoid this, it is preferable to subject the granules to hydrophilic treatment after coating or after heat treatment. The method of hydrophilization is not particularly limited. For example, a surfactant and / or Si may be added to the outermost layer of the coated granule.
It is easiest to attach fine powder such as O ₂ dust.

According to the manufacturing method of the first invention of the present application,
Leakage of the pesticide component in d1 of the obtained time-release coated pesticide granule can be suppressed. On the other hand, according to the production method of the second invention of the present application, the obtained time-release coated pesticide granule can be stored. Over time of the release function due to the above. If the first invention of the present application and the second invention are carried out independently, the respective effects can be obtained, and it is effective only by itself, but the first invention of the present application and the second invention of the present application are simultaneously performed, A method for producing a coated pesticide granule in which a resin solution obtained by dissolving a thermoplastic resin in a solvent is sprayed on the surface of pesticide particles containing one or more pesticide components to form a film on the surface of the particles. Has an average particle size of 0.3 to 3.0 m
m, and a nozzle having a sprayed droplet diameter of 80 to 300 μm is used. When the melting point of the thermoplastic resin to be used is T _m , the surface temperature of the pesticide particles is equal to or less than (T _m −5). After forming the resin film, (T _m −60) or more (T _m −
A method for producing a time-release coated pesticide granule which is heat-treated at a temperature of less than 5) is particularly preferable because it is possible to suppress the leakage of the pesticide component and also to suppress the change over time of the release function due to storage.

[0038]

The present invention will be described below with reference to examples.
The present invention should not be limited by these examples. In the following examples, “%” is “% by weight” unless otherwise specified.

"Production and Evaluation of Examples 1 to 6 and Comparative Examples 1 to 4" 1-1 Production of core material 1,2,5,6-tetrahydropyrrolo [3,2,1-ij] quinoline as an agricultural chemical component 3 parts by weight of a pesticide containing 98% of 4-one, 50 parts by weight of bentonite, 42 parts by weight of clay, and 5 parts by weight of talc were uniformly mixed by a mixer and kneaded with a kneader. This mixture was screw extruded granulator with a screen die diameter of φ0.5,
It extruded and granulated using four types of 0.8, 1.0, and 2.0 mm, and obtained the primary agricultural chemical granule. Screen die diameter φ
2.0 mm was vertical pressing granulation, and the others were performed by horizontal pressing granulation. The granulated product was subjected to a circular disk type granulator (made by Fuji Paudal Co., Ltd., Malmerizer QJ400) to have a circularity coefficient of 0.
The smoothing process was performed until the number became 7 or more. In the treatment method, the granulated material was weighed and supplied to a rotating disk type granulator, and granulated under the following operating conditions. After sizing, the mixture was dried under a condition of 80 ° C. using a hot air circulating drier, and classified by a vibrating sieve to obtain a secondary pesticide granule (core material) containing 2.8% of a pesticide component to be coated. . Core material is 0.295mm sieve (Tyler4
8) Pass product, 0.295-0.833mm product (Tile
r20 pass Tyler 48 on product), 0.833-1.
397 mm product (Tyler 12 pass Tyler 20 on product), 1.397 to 1.981 mm product (Tyler 9 pass Tyler 12 on product), 1.981 to 2.794 m
m product (Tyler7 pass Tyler9 on product), 2.7
It was sieved to a 94 mm sieve (Tyler 7) on product. Core material A, core material B, core material C, core material D, core material E,
Core material F was used. Using 100 randomly picked cores, the circularity coefficient was measured with PIAS-IV manufactured by Pierce Co., Ltd., and the average value of the circularity coefficients of all cores A to F was 0.9 or more. Was. Operating conditions Operating method: Batch type Operating time: 3 minutes Plate pitch: 1 mm Number of revolutions: 788 r / min Charge: 2 liters (per time)

1-2 Coating of core material: Ethylene-carbon monoxide copolymer or low-density polyethylene (resin names used are shown in Table 1) 30% by weight and talc (average particle size 5 μm) 70% by weight Using the coating material, the resin is dissolved in tetrachloroethylene as a solvent at 90 ° C. and stirred to form a coating material solution, and the concentration of the coating material is adjusted to be 5.0% by weight with respect to the coating material solution, and the coating material is dissolved. The liquid was adjusted. Subsequently, using the spouted bed coating apparatus shown in FIG. 1, the core material obtained by the above “manufacture of the core material” was combined with the nozzle and coating composition shown in Table 1 to obtain the coating material solution. Were used to coat the cores A to F to obtain the coated pesticide granules of Examples 1 to 6 and Comparative Examples 1 to 4. The production was performed according to the following method. The coverage is 20% by weight, and the ratio of the weight (b) of the coating to the coated pesticide granules is 100% by weight of the sum of the weight (a) of the core material and the weight (b) of the coating. rate(%)
= B × 100 / (a + b)]. Core material: 3 kg Hot air temperature: 100 to 130 ° C. Hot air volume: 80 to 100 m ³ / hr Spray speed: 250 ml / min (in terms of pure water) Nozzle used: one-fluid nozzle (droplet diameter is shown in Table 1) Coating step Was started from the time when the core material temperature during the flow reached 70 ° C., and sprayed using a one-fluid nozzle for a predetermined time so that the core material surface temperature became constant at 70 ° C. The droplet diameter is the Sauter average particle diameter (d ₃₂ = Σnd ³ / Σnd ² ).

[0041]

[Table 1] ECO: ethylene-carbon monoxide copolymer MFR = 0.
75 g / 10 min (JIS K6760), CO =
0.95% by weight, d = 0.93 g / cm ³ (JIS K
6760), melting point 120 ° C. (ASTM D3418) LDPE: low density polyethylene MFR = 23 g / 10
min (ASTM D1238), d = 0.916 g /
cm ³ (ASTM D1505), melting point 105 ° C (AS
TM D3418)

1-3 Release Test Release tests of the coated pesticide granules of Examples 1 to 6 and Comparative Examples 1 to 4 obtained by the above “coating of core material” were carried out according to the following description. The release test measures the time (release start time) until the inner core material is released to the outside when the coated pesticide granules are cracked and the coating is broken. A coated test tube (12 mm x
72 mm) and 1.5 ml of water.
After administration of the granules, they were capped. This is 100
Using a tube (grain), the number of disintegrations of the coated pesticide granules was counted under a constant water temperature of 20 ° C. Observations were made daily for one week from the start of the test, and every two days thereafter. The cumulative release rate is the number of disintegrations of the test granules. The cumulative release rate was plotted on the ordinate and the elapsed days was plotted on the abscissa, and a graph was created by plotting the respective data. The number of days from the start of the test to the 10% release (release inhibition period) is “d1”, and the number of days from the start of the test to the 90% release (component release period) is “d2”. /
The release rate at the time corresponding to No. 2 was “1/2 · d1”.
Table 2 shows the results.

[0043]

[Table 2]

From the results shown in Table 2, the products of the present invention (Examples 1 to 3)
The release of 6) was ・ · d1 = 2% or less, indicating an excellent release suppressing function. On the other hand, when the pesticide of Comparative Example 1 was observed, it was found that some particles adhered and caused a blocking to form an eruption, and did not appear to be completely covered, and there was much leakage during the release suppression period. In Comparative Example 2 in which the droplet diameter exceeded 300 μm, blocking was observed as in Comparative Example 1,
There were many leaks during the release control period. Drop size is 50μ
Comparative Examples 3 and 4 having less than m did not show blocking like Comparative Examples 1 and 2, but leaked more during the release suppression period. It is presumed that the coating peeled off due to insufficient adhesive strength of the coating material during the film formation and the coating was damaged.

"Production and Evaluation of Examples 7 to 10 and Comparative Examples 5 to 8" 2-1 Production of core material 1,2,5,6-tetrahydropyrrolo [3,2,1-ij] quinoline as an agricultural chemical component 3 parts by weight of a pesticide containing 98% of 4-one, 50 parts by weight of bentonite, 42 parts by weight of clay, and 5 parts by weight of talc were uniformly mixed by a mixer and kneaded with a kneader. This mixture is screen-diameter φ0.9mm with a screw extrusion type granulator.
And extruded using a die to obtain a primary agricultural chemical granulated product. The granulated product is supplied to a rotating disk type granulator (Fuji Paudal,
A smoothing process was performed with a circularizer QJ400) until the circularity coefficient became 0.7 or more. In the treatment method, the granulated material was weighed and supplied to a rotating disk type granulator, and granulated under the following operating conditions. After sizing, use a hot air circulating drier for 80
After drying under the condition of ° C., the mixture was classified with a vibrating sieve to obtain a pesticide component of 2.8.
1.397 to 1.981 mm to be subjected to a coating containing
A secondary pesticide granulated product (core material) of a product (Tyler 9 pass Tyler 12 on product) was obtained. Core material 1 taken out at random
When the circularity coefficient was measured with PIAS-IV manufactured by Pierce Co., Ltd., using 100 grains, the average value of the circularity coefficient was 0.1.
9 or more. Operating conditions Operating method: Batch type Operating time: 3 minutes Plate pitch: 1 mm Number of revolutions: 788 r / min Charge: 2 liters (per time)

2-2 Coating of core material Using the coating material composition shown in Table 3, a resin was dissolved in tetrachloroethylene as a solvent at 90 ° C. and stirred to obtain a coating material dissolving solution. Was adjusted to be 5.0% by weight. Subsequently, using the spouted bed coating apparatus shown in FIG. 1, the core material obtained by the above-mentioned “2-1. And the coated pesticide granules of Comparative Examples 5 to 8 were obtained. The production was performed according to the following method. The coverage is the ratio of the weight (b) of the coating to the coated pesticide granules when the sum of the weight (a) of the core material and the weight (b) of the coating is 100% by weight. ) = B × 10
0 / (a + b)]. Core material: 3 kg Hot air temperature: 120 ° C. Hot air volume: 80 m ³ / hr Spray speed: 250 ml / min (converted to pure water) Nozzle used: one-fluid nozzle (droplet diameter 130 μm) The spraying was started using a one-fluid nozzle so that the core material temperature during the flow reached a predetermined temperature and the core material surface temperature was kept constant at the predetermined temperature.

[0047]

[Table 3] PO1: ethylene-carbon monoxide copolymer MFR = 0.
75 g / 10 min (JIS K6760), CO =
0.95% by weight, d = 0.93 g / cm ³ (JIS K
6760), melting point 120 ° C. (ASTM D3418) PO2: low density polyethylene MFR = 23 g / 10 m
in (ASTM D1238), d = 0.916 g / c
m ³ (ASTM D1505), melting point 105 ° C. (AST
MD3418) PO3: Low-density polyethylene (MFR = 23 g / 10 m)
in (ASTM D1238), d = 0.916 g / c
m ³ (ASTM D1505), melting point 105 ° C. (AST
MD3418)) A blend of 98 parts by weight and 2 parts by weight of poly-ε-caprolactone (Mn = 80,000, melting point 60 ° C.) PO4: Ethylene-carbon monoxide copolymer (MFR = 0.
75 g / 10 min (JIS K6760), CO =
0.95% by weight, d = 0.93 g / cm ³ (JIS K
6760), melting point 120 ° C. (ASTM D3418))
99 parts by weight of poly (ethylene oxide) (Mw = 25
(000-300,000, melting point 65-67 ° C) 1 part by weight

2-3 Heat treatment 1 k of coated pesticide granules obtained in 2-2 "Coating of core material"
g, and a heat treatment was performed for 30 minutes with hot air having a constant temperature shown in Table 3 using the heat treatment apparatus shown in FIG. An activated carbon filter was installed at the exhaust port, and the solvent in the exhaust was adsorbed and collected.

2-4 Release Test Release tests were carried out on the coated pesticide granules of Examples 7 to 10 and Comparative Examples 5 to 8 according to the following description. The release test was performed for each of the coated pesticide granules of Examples 7 to 10 and Comparative Examples 5 to 8 obtained immediately after production (immediately after heat treatment) and after production (heat treatment).
Polyethylene bags of 0.063 mm thickness in 100 g increments (trade name: Reed frozen storage bag, 1
Two samples left for a week were used. Sample is 30 ° C
It was rapidly cooled below and used for the test. In the release test, the time until the inner core material is released to the outside by the cracking of the coated pesticide granules and the destruction of the film (release start time)
Is measured. 1.5 ml of water was placed in a test tube (12 mm × 72 mm) with the coated pesticide granules, and one cap was administered per test tube, followed by capping. Using 100 tubes (particles) per test section, the number of disintegrations of the coated pesticide granules was counted under the condition of a constant water temperature of 20 ° C. Observations were made daily for one week from the start of the test, and every two days thereafter. The cumulative release rate is the number of disintegrations of the test granules. The cumulative release rate was plotted on the ordinate and the elapsed days was plotted on the abscissa, and a graph was created by plotting the respective data. The number of days from the start of the test to the 10% release (release suppression period) was “d1”, and the number of days from the start of the test to the 90% release (component release period) was “d2”.
Table 4 shows the results.

[0050]

[Table 4]

As is clear from the results shown in Table 4, in the coated pesticide granules of Examples 7 to 10 which were heat-treated, the measurement results of d1 and d2 immediately after the production and d1 and d2 after one week of standing.
There was hardly any difference in the results of the measurements. On the other hand, in the samples of Comparative Examples 5, 7, and 8, the measurement results of d1 and d2 immediately after production and the measurement results of d1 and d2 after standing for one week were significantly different. In Comparative Examples 5 and 8, no heat treatment was performed, but in the release test after standing, the release characteristics changed. In Comparative Example 6, the coating softened at the stage of heat treatment, and agglomeration in which particles adhered to each other occurred. It seems that the coating had some influence, and both d1 and d2 were extremely shorter than those of Example 7 having the same coating composition. In Comparative Example 7, the effect of the heat treatment was not observed.

[0052]

The time-release coated pesticide granules obtained by the production method of the present invention are superior to the conventional products in the following points. Leakage during the release control period is small, and phytotoxicity can be minimized. There is little change over time during storage, and stable quality can be maintained. When the first invention of the present application and the second invention of the present application are performed at the same time, leakage during the release suppression period is small, and further, the change with time during storage is small.

[Brief description of the drawings]

FIG. 1 is a sectional view of a spouted bed coating apparatus.

[Explanation of symbols]

 1. Spout tower 2. Spray nozzle 3. 3. Pesticide granules for coating (core material) Hot air temperature 5. Coating material introduction pipe 6. Guide tube

FIG. 2 is a heat treatment apparatus.

Claims (2)

[Claims] 1. A method for producing a coated pesticide granule in which a resin solution obtained by dissolving a thermoplastic resin in a solvent is sprayed on the surface of pesticide particles containing one or more pesticide components to form a film on the surface of the particles. In the above, the average particle diameter of the particles is 0.3 to 3.0 m.
m, and using a nozzle having an average particle diameter of droplets in the range of 80 to 300 μm when sprayed with pure water at 21 ° C., wherein the time-release type coated agricultural chemical granule is used. 2. A resin solution obtained by dissolving a thermoplastic resin in a solvent is sprayed on the surface of pesticide particles containing one or more pesticide components, and is used in a film-forming step of forming a resin film on the surface of the particles. Assuming that the melting point of the thermoplastic resin is T _m ° C, a resin film is formed at a surface temperature of the pesticide particles of (T _m −5) ° C. or less, and then (T _m −60) ° C. or more (T _m −5) ) ℃
A method for producing a time-release type coated pesticide granule, which comprises heat-treating at a temperature of less than.