JPH0686361B2 - Granular pesticide manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of granulating a poorly water-soluble pesticide dispersion slurry by countercurrent spray drying, and more specifically, a storage surface of a product,
The present invention relates to a method for producing a granular pesticide, which is advantageous in terms of transportation cost, easy to suspend, and has physical properties without environmental pollution such as dust.

[Conventional technology and its problems]

There are various dosage forms such as granules, emulsions, and flowable agents in addition to wettable powders, but wettable powders can contain high levels of active agricultural chemicals and at the same time It is excellent in that it can be formulated regardless of the type.

However, since wettable powders, together with inorganic mineral powders, are used as pesticide raw materials, they are pulverized into fine powders, so when preparing a spray solution for use, the fine powders will rise as soon as the bag is opened, and the preparation will need to be weighed. It was hanging.

Therefore, in recent years, attempts have been made to granulate wettable powders.
However, when the conventional wettable powder is granulated as it is, there are various problems that it does not disintegrate in water and does not give a stable dispersion liquid.

As a method for solving this problem, a powdery wettable powder prepared by mixing a pesticide active ingredient with starch and a water-soluble inorganic salt (Japanese Patent Publication Sho 53-1257).
However, it was not satisfactory in terms of initial dispersibility, self-dispersibility, suspension stability, environmental pollution due to dust, and the like.

Also, when the pesticide dispersion slurry is granulated by a co-current type spray dryer, it is difficult to produce granules having a low bulk density and a large particle size, powdering, and not completely satisfactory in terms of transportation cost, etc. Further, there is a problem that the cost for performing the spray drying is high.

[Means for solving problems]

Therefore, the present inventors have found that the bulk density of the granular material is low, the particle diameter of the granule is large, and when it is put into water, the hydration property and the disintegrating property are excellent, and a stable dispersion liquid is obtained. As a result of earnest research to obtain a wettable powder at low cost, it was found that the above object can be achieved by performing granulation by spray drying by a countercurrent method under specific conditions, and completed the present invention. .

That is, the present invention relates to a method for producing a granular pesticide, which comprises subjecting a concentrated dispersion slurry containing water-insoluble pesticide powder to countercurrent spray drying under the following conditions (i) and (ii).

(I) 6.8 ≦ de ^0.70 × P ^−0.40 × μ ^0.22 × σ ^0.60 (Ii) Spray nozzle diameter 0.5 to 4.0 mm, spray pressure 5 to 250 kg / cm ² (pressurizing nozzle) Hot air inlet temperature 150 to 300 ° C. Exhaust air temperature 60 to 120 ° C. According to the present invention, 50% or more of particles have bulk density It is possible to obtain a granular pesticide having physical properties of 150 to 400 g / and having excellent hydration properties and disintegration properties when added to water.

The expression (i) means that the particle diameter after spray drying and the bulk density are the spray nozzle diameter de, the spray pressure P, the slurry viscosity μ,
That is, it is governed by the exponential function formula of the slurry surface tension δ.

That is, when the spray pressure is constant, the larger the nozzle diameter, the larger the spray droplets. At this time, the size of the droplets is closely related to the slurry viscosity and the slurry surface tension.
Further, when the nozzle diameter is constant, the smaller the spray pressure is, the larger the droplet diameter is, but also at this time, the slurry viscosity and the surface tension are closely related.

According to the research conducted by the present inventors, the index applied to each variable is 0.7 to the nozzle diameter de, −0.4 to the spray pressure, 0.22 to the slurry viscosity, and to the slurry surface tension.
It was found that particles having a low bulk density, a large particle size, no dust, and excellent dispersibility in water can be obtained by spraying under conditions such that the product of these values is 0.6 or more. At this time, the nozzle diameter is 0.5 to 4.0 mm, preferably 0.
8-3.8 mm, spray pressure 5-250 kg / cm ² , preferably 10-8
0kg / cm ² , slurry viscosity is 1 to 10000cps (25 ℃) (B type 3
0 rpm No. 2), preferably 10 to 5000 cps, slurry surface tension is 10 to 72 dyn / cm (25 ° C.), preferably 20 to 70 dyn / cm,
The hot air inlet temperature is 150 to 300 ° C, preferably 150 to 250 ° C, and the exhaust air temperature is 60 to 120 ° C, preferably 80 to 110 ° C.

Also, fine powder having an average particle size of 10 μm or less, that is, zeolite, silica, other inorganic substances or metal soaps, etc. are added to and mixed with the spray-dried particles to obtain a powder having excellent fluidity.

Further, the dispersant used in the agricultural chemical dispersion slurry is preferably one or more selected from the following compound groups (1) to (4). By using these, it is possible to obtain a powder or granule having excellent hydration properties and disintegration properties when poured into water.

(1) A water-soluble or water-dispersible polymer containing, as an essential component, one or more selected from the group of monomers consisting of unsaturated carboxylic acids and their derivatives.

(2) A water-soluble or water-dispersible polymer containing styrene sulfonate as an essential constituent monomer.

(3) A formalin condensate of a sulfonated aromatic compound or a salt thereof, which may have a hydrocarbon group as a substituent.

(4) Metal phosphate.

The dispersants (1) to (4) according to the present invention will be specifically described.

(1) A water-soluble or water-dispersible polymer containing, as an essential component, one or more selected from the group of monomers consisting of unsaturated carboxylic acids and their derivatives.

Monomers used for the production of this polymer include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, unsaturated dicarboxylic acids such as maleic acid, and their derivatives such as alkyl esters (methyl esters) of the above acids. Etc.), alkali metal salts (such as soda salts), ammonium salts and organic amine salts (such as triethanolamine salts),
There are mixtures of these. In addition to these monomers, vinyl acetate, isobutylene, diisobutylene, as a copolymerization component,
Copolymerizable monomers such as styrene can also be added.

The method of polymerizing these monomers is a conventionally known method. The ratio of the monomer components and the degree of polymerization of the polymer are not particularly limited, but the polymer needs to be at least water-soluble or water-dispersible.

Specific examples include acrylic acid polymer, methacrylic acid polymer, copolymer of acrylic acid and methacrylic acid, copolymer of acrylic acid and methacrylic acid polyoxyethylene ester, acrylic acid and acrylic acid methyl ester. , A copolymer of acrylic acid and vinyl acetate, a copolymer of acrylic acid and maleic acid, a copolymer of maleic acid and isobutylene, a copolymer of maleic acid and styrene, and the like. Salts with alkali metals, ammonia and organic amines are mentioned. Two or more kinds of these polymers can be used.

(2) Water-soluble or water-dispersible polymer containing styrene sulfonate as an essential constituent monomer A homopolymer of styrene sulfonate is easily prepared by polymerizing styrene sulfonate or sulfonation of polystyrene. Can be manufactured. The styrene sulfonate polymer has a skeleton represented by the following formula.

The molecular weight is 1000 or more, preferably 10,000 to 3,000,000. M
Means an alkali metal salt such as Li, Na, K or NH ₃ , an alkylamine, an alkanolamine and the like.

In addition, the copolymer of styrene sulfonate and other monomer copolymerizes styrene sulfonate and other monomer, or sulfonates the copolymer of styrene and other monomer. Therefore, it can be easily manufactured. As the monomer of the copolymerization partner, alkyl acrylate, alkyl methacrylate, vinyl alkyl ether, vinyl acetate,
Hydrophobic monomers such as ethylene, propylene, butylene, butadiene, diisobutylene, vinyl chloride, vinylidene chloride, acrylonitrile and styrene, and acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, vinyl alcohol, acrylamide Hydrophilic monomers such as methacrylamide, diacetoneacrylamide, N-vinylpyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, methacrylsulfonic acid, xylenesulfonic acid, and naphthalenesulfonic acid are used. Examples of preferable copolymers include (meth) acrylic acid-styrene sulfonic acid copolymer salts. The molar ratio of (meth) acrylic acid and styrenesulfonic acid in the copolymer is 1 /
It is 10 to 10/1, preferably 1/3 to 7/1. The average molecular weight is 100 to 100,000, preferably 10,000 to 700,000. As the salt of the copolymer, sodium salt, potassium salt, ammonium salt, diethanolamine salt, triethanolamine salt, monoisopropanolamine salt, diisopropanolamine salt, triisopropanolamine salt, 2
-Amino-2-methylpropane-1,3-diol salt and the like can be mentioned. Further, it may be left in the unneutralized portion to the extent that the performance is not impaired.

(3) Formalin condensate of a sulfonate of an aromatic compound which may have a hydrocarbon group as a substituent or a salt thereof. Specifically, a petroleum sulfonic acid derivative, a lignin sulfonic acid derivative, a naphthalene sulfonic acid derivative, a xylene sulfonic acid derivative. , Formalin condensates such as alkylbenzene sulfonic acid derivatives.

These formalin condensates include, for example, naphthalene, alkyl-substituted benzene, alkyl-substituted naphthalene, anthracene, alkyl-substituted anthracene, lignin, and those having an aromatic ring in petroleum residue, which are sulfonated by a general method, followed by a salt formation reaction. , And further formalin condensation. In this case, the condensation degree is preferably 2 to 30, more preferably 3 to 10. here,
When the degree of condensation is less than 2, the effect of condensation is small, and
When it exceeds 30, the polymer has a high molecular weight, which causes practical problems due to solubility and the like.

As the aromatic compound to be used, various ones can be used, but it is preferable to use lignin, xylene, toluene, naphthalene, or alkylnaphthalene having 1 to 6 carbon atoms, and of course, a mixture thereof. Good.

As salts, alkali metals such as sodium and potassium, alkaline earths such as calcium, amines,
Ammonium salts and the like are also used.

(4) Examples of the metal phosphate include tripolyphosphoric acid, pyrophosphoric acid, hexametaphosphoric acid, primary phosphoric acid, secondary phosphoric acid,
Examples thereof include sodium, potassium, and other alkali metal salts such as tertiary phosphoric acid. These may be used alone or in combination of two or more.

The compounding ratio of the dispersant in the wettable powder is preferably 1 to 50 parts by weight, more preferably 2 to 40 parts by weight. Particularly in the case of a high concentration drug substance, 10 parts by weight or more is preferable.

The pesticides used in the present invention are insecticides, fungicides, acaricides, herbicides, and plant growth regulators. For example, insecticides include 1-naphthyl-N-methylcarbamate [NAC], 0,0 -Diethyl-0- (3-oxo-2-phenyl-2H
-Pyridazin-6-yl) phosphorothioate [Ofunack], as acaricide, tricyclohexyltin hydroxide [Plictran], hexakis (B, B-dimethylphenethyl) distannoxane [Osadan], as a bactericide Is zinc ethylene bis (dithiocarbamate) [Dithane], bisdimethyldithiocarbamoyl-zinc ethylene bisdithiocarbamate [Bis-dithan
e)], bis (dimethyldithiocarbamoyl) disulfide [Thiuram], methyl-1- (butylcarbamoyl) -2-benzimidazole carbamate [Benomyl], tetrachloroisophthalonitrile [Daconi (Daconi)
l)], 3- (3,5-dichlorophenyl) -5-methyl-5-vinyl-1,3-oxazolidine 2,4-dione [ronilan (Ro
nilan)], N- (3,5-dichlorophenyl) -1,2-dimethylcyclopropane-1,2-dicarboximide [Sumilex (S
umilex)], 3- (3,5-dichlorophenyl) -N-isopropyl-
2,4-Dioxoimidazolidine-1-carboxamide [Rovrol], 3-allyloxy-1,2-benzisothiazole 1,1-dioxide [Oryzemate], diisopropyl 1,3-dithiolane- 2-ylidene malonate [Fuji-One], 5-methyl-1,2,4-triazole [3,4-b] benzothiazole [Beam], 3'-isopropoxy-2- Methylbenzanilide [Mepronil], 2-isopropylphenyl-N-methylcarbamate [MIPC], 3,5-dimethylphenyl-N-methylcarbamate, dimethyl [1,2-phenylene) bis- (iminocarbonothioyl) )] Biscarbamate [Topzine M], N '-(2-methyl-4-chlorophenyl) N, N-dimethylformamidine [Chlorophenamid] Down], S- methyl -N- (methyl Ka'bah carbamoyloxy) thioacetimidate, 1,2 Jipuromo-3-chloropropane, N- (trichloromethyl thio) -4-cyclohexene -
1,2-dicarbocimido, cis-N-[(trichloromethyl) thio] -4-cyclohexene-1,2-dicarboximide [captan], cis-N-[(1,1,2,2tetrachloroethyl) thio ] 4
-Cyclohexene 1,2-dicarboximide [difortan], and as a herbicide, 4-2,4-dichlorobenzoyl) 1,3-dimethyl-5-virazolyl-P-toluenesulfonate [Sunbird (Sa
nbird)] Methyl 5- (2,4-dichlorophenoxy) -2-nitrobenzoate [Modown], 1- (α, α-dimethylbenzyl) -3- (p-tolyl) urea [Dimuron] ], Α- (2-naphthoxy) propion-anilide [Uribest], 3- (3,4-dichlorophenyl) -1,1-dimethylurea [Karmex], 2-chloro-4,6 -Bis- (ethylamino) -1,3,5-triazine [Simazine], 1- (4-difluorochloromethylcapto-3-chlorophenyl) -3,3-dimethylurea [KUE], 2,4 -Dichlorophenyl-4-nitrophenyl ether, 2,4,6-trichlorophenyl-4-nitrophenyl ether, 3,4-dichloropropionanilide [DCPA], 2-methylthio-4,6-bis (ethylamino) -S- triazine [simetryn], 3-isopropyl-2,1 benzothiadiazinones -
(4) -2,2-Dioxide [pentazone], which is essentially insoluble in water. It is possible to use one type of these, or to use two or more types and mix easily water-soluble drug substances to prepare a preparation.

The content ratio of the agricultural chemical raw material in the wettable powder is preferably 20 to 98 parts by weight, more preferably 30 to 85 parts by weight. In the present invention, the high-concentration drug substance wettable powder having remarkable effects such as hydration property and disintegration property is 50 parts by weight or more, particularly 60 to 85 parts by weight.

Mineral powder may be added to the wettable powder as needed. Specific examples of the mineral powder include wax stone, talc,
Examples include kaolin, calcium carbonate, bentonite, silica powder, limestone powder, acid clay, diatomaceous earth powder, gypsum, pumice powder, shellfish powder, mica powder, and colloidal hydrous sodium silicate.

When the mineral powder is blended, the proportion of the mineral powder in the wettable powder is 0 to 60 parts by weight, preferably 2 to 50 parts by weight.

In addition to the above components, a surfactant such as polyoxyethylene alkylaryl ether may be blended as a wetting agent, if necessary.

In carrying out the present invention, (1) to
If necessary, a dispersant selected from (4), a dispersant other than this, a water-soluble thickener, an antifoaming agent, a decomposition rod material, an agglomeration inhibitor, and the like can be added.

As the dispersant, in addition to the compounds (1) to (4) described above, a nonionic surfactant and / or an anionic surfactant is used. Examples of the nonionic surfactant and / or anionic surfactant include polyoxyethylene (hereinafter referred to as POE) alkyl (having 6 to 2 carbon atoms).
2) Non-ion such as ether, POE alkyl (C4-18) phenol ether, polyoxypropylene polyoxyethylene (block or random) alkyl ether, POE phenylphenol ether, POE styrenated phenol ether, POE tribenzylphenol ether Surfactant, alkylbenzene sulfonate,
Alkyl sulfonate, POE Alkyl sulfonate, POE
Alkyl phenyl ether sulfonate, POE alkyl phenyl ether phosphate ester salt, POE phenyl phenol ether sulfonate salt, POE phenyl phenol ether phosphate ester salt, naphthalene sulfonate salt,
POE Tribenzylphenol ether sulfonate, POE
Anionic surfactants such as tribenzyl phenylphenol ether phosphate salts are mentioned. These can be used alone or in combination. Its content is 0 to 20 weight percent in the composition, preferably 1 to 10
Weight percent.

As the water-soluble thickener, natural, semi-synthetic and synthetic water-soluble thickeners can be used, natural mucilage, zansan gum derived from microorganisms, Zanflow, plant-derived pectin,
Gum arabic, guar gum, etc., methyl or carboxyalkylated, hydroxyalkylated (including methylcellulose, carboxymethylcellulose, hydroxymethylcellulose) of cellulose or starch derivative in semi-synthetic mucilage, and polyacrylic acid in synthetic mucus. Specific examples include salts, polymaleic acid salts, and polyvinylpyrrolidone. The water-soluble thickener is incorporated in the composition in an amount of about 0 to 3.0% by weight, preferably about 0.05 to 0.5% by weight.

Anti-foaming agents may optionally be included up to about 2% by weight to prevent foaming during formulation and anti-degradants up to about 7% by weight to prevent decomposition of organophosphorus biocides, especially during storage. Is preferred. The anti-foaming agent is not particularly limited, and any of them can be used. Specific examples thereof include polypropylene glycol and silicone oil.
Examples of the decomposition inhibitor include epichlorohydrin, phenylglycidyl ether, and allylglycidyl ether. If desired, a solid biocide anti-aggregation agent (e.g., polyoxyethylene-polyoxypropylene block polymer), an anti-drift agent (e.g., sorbitol), etc. may be added as long as the effects of the present invention are not impaired. .

The pesticide-dispersed slurry may be prepared by dispersing the dry-milled drug substance using the dispersant according to the present invention, or in order to obtain a finer particle size, grind by a wet-grinding method such as a sand grinder. Of course, there is no problem with the slurry.

Conventionally, in order to obtain a powder-like wettable powder, a dry tableting method or a pesticide raw material powder or a pesticide raw material and an inorganic mineral powder sprayed with the pesticide raw material is added with a dispersant and an appropriate amount of water. Further, a method in which an auxiliary agent is blended if desired is kneaded, and a wet granulation method such as rolling granulation, fluidized bed granulation, extrusion granulation, etc. is carried out. It is significantly inferior to the product of the present invention in terms of compatibility and dispersibility. Also, when the pesticide-dispersed slurry is granulated by a co-current type spray dryer, the shapes such as bulk density and particle size are inferior to those of the product of the present invention.

〔The invention's effect〕

According to the present invention, it is possible to obtain a powdery granular wettable powder which contains an active ingredient in a high concentration, is excellent in hydration property and disintegration property, and has good suspension stability. Also, since the particle size is large, it is easy to store and transport, and there is little scattering during handling. Particularly, the initial dispersibility in a high-concentration pesticide bulk wettable powder is improved. The effect of the dispersant of the present invention is remarkable, the pesticide raw material is 90% by weight or less,
Above all, it is a system of 50 to 85% by weight. At that time, the amount of the dispersant added may be 1/2 to 1/3 of the wet granulation method or the like and 3 to 15% by weight.

Further, the granular pesticide of the present invention self-disperses immediately after being added to water and gives a dilute suspension having no change in particle size from the particle size at the time of preparation of the pesticide dispersion slurry.

〔Example〕

The present invention will be specifically described below with reference to Examples and Comparative Examples.

Example 1 10 parts by weight of soda salt of a copolymer of acrylic acid and maleic anhydride and 80 parts by weight of Glauber's salt were added to 80 parts by weight of a pre-ground captan raw material.
By adding 60 parts by weight of water and 60 parts by weight of water to prepare a slurry, a spray nozzle diameter of 2.5 mm, a spray pressure of 15 kg / cm ² , a hot air inlet temperature of 200 ° C.,
Granules were prepared using a countercurrent spray dryer at an exhaust air temperature of 110 ° C.

Example 2 A slurry was prepared by adding 20 parts by weight of a soda salt of a copolymer of acrylic acid and polyoxyethylene methacrylate, 10 parts by weight of white carbon, and 70 parts by weight of water to 80 parts by weight of a pre-ground captan raw material, Powder particles were prepared using a countercurrent spray dryer under the conditions of spray nozzle diameter 1.2 mm, spray pressure 40 kg / cm ² , hot air inlet temperature 180 ° C., and exhaust air temperature 100 ° C.

Example 3 A slurry was prepared by adding 10 parts by weight of a formalin condensate of sodium salt of naphthalenesulfonic acid, 10 parts by weight of clay, and 60 parts by weight of water to 80 parts by weight of a raw material of difortan pulverized in advance, and a spray nozzle having a diameter of 1.5 mm and spraying. Pressure 20 kg / cm ² , hot air inlet temperature 180
The powder and granules were prepared using a counter-current type spray dryer under the conditions of ℃ and exhaust air temperature of 100 ℃.

Example 4 70 parts by weight of a pre-milled Topzin M raw material was added to 10 parts by weight of a copolymer of a sodium salt of styrenesulfonic acid and a sodium salt of xylenesulfonic acid, 10 parts by weight of Na tripolyphosphate, and 10 parts of clay.
Parts by weight, white carbon 10 parts by weight, water 60 parts by weight to prepare a slurry, spray nozzle diameter 2.5 mm, spray pressure 30 k
Granules were prepared using a countercurrent spray dryer under the conditions of g / cm ² , hot air inlet temperature of 250 ° C, and exhaust air temperature of 100 ° C.

Example 5 To 70 parts by weight of Topzin M drug substance, 10 parts by weight of sodium ligninsulfonate sodium formalin condensate salt, 20 parts by weight of clay, and 80 parts of water
Parts by weight were added and wet pulverized for 2 hours with a sand grinder to prepare a slurry having an average particle diameter of 3.5μ. Spray nozzle diameter 3.0mm, spray pressure 30kg / cm ² , hot air inlet temperature 200 ℃,
Granules were prepared using a countercurrent spray dryer under the condition of exhaust air temperature of 120 ° C.

Example 6 80 parts by weight of difortan raw material, 10 parts by weight of a copolymer of styrene sulfonic acid soda salt and maleic anhydride, 10 parts by weight of clay, and 80 parts by weight of water were added, and the mixture was pulverized with a sand grinder for 2 hours to obtain an average particle. A slurry having a diameter of 3.0 μ was prepared. Spray nozzle diameter 1.5 mm, spray pressure 40 kg / cm ² , hot air inlet temperature 200
℃, the exhaust air temperature of 110 ℃ under the conditions of a countercurrent spray dryer to prepare powder.

Comparative Example 1 80 parts by weight of a previously crushed captan raw material was mixed with 10 parts by weight of a soda salt of a copolymer of acrylic acid and maleic anhydride, and 10 parts of Glauber's salt.
Parts by weight, 60 parts by weight of water to prepare a slurry, spray nozzle diameter 1.5 mm, spray pressure 50 kg / cm ² , hot air inlet temperature 180 ° C.,
Granules were prepared using a co-current type spray dryer under the condition of exhaust air temperature of 100 ° C.

Comparative Example 2 70 parts by weight of a pre-ground Topzine M raw material was added to 10 parts by weight of a copolymer of soda salt of styrene sulfonic acid and sodium salt of xylene sulfonic acid, 10 parts by weight of clay, 10 parts by weight of white carbon, and 10 parts by weight of sodium tripolyphosphate. Was added to prepare a slurry, and powder particles were prepared by a countercurrent spray dryer under the conditions of a spray nozzle diameter of 0.8 mm, a spray pressure of 50 kg / cm ² , a hot air inlet temperature of 200 ° C., and an exhaust air temperature of 110 ° C.

Comparative Example 3 80 parts by weight of difortan raw material, 10 parts by weight of a copolymer of styrene sulfonic acid soda salt and maleic anhydride, and 80 parts by weight of water were added, and the mixture was pulverized with a sand grinder for 2 hours to obtain a slurry having an average particle diameter of 2 μm. Prepared. Spray nozzle diameter 0.6m
m, spray pressure 25 kg / cm ² , hot air inlet temperature 200 ° C, exhaust air temperature 11
Granules were prepared using a countercurrent spray dryer at 0 ° C.

Comparative Example 4 80 parts by weight of a previously crushed captan raw material was mixed with 10 parts by weight of a soda salt of a copolymer of acrylic acid and maleic anhydride, and 10 parts of Glauber's salt.
20 parts by weight of water and 20 parts by weight of water were kneaded and granulated with an extrusion granulator equipped with a 0.8 mm screen, sized to 20 to 32 mesh, and dried at 30 ° C. to give granules.

Comparative Example 5 70 parts by weight of Topzin M raw material previously crushed, 10 parts by weight of a copolymer of styrene sulfonic acid soda salt and xylene sulfonic acid soda salt, 10 parts by weight of clay, and 10 parts by weight of white carbon.
By weight, 30 parts by weight of water was added and kneaded, and the mixture was granulated by an extrusion granulator equipped with a 0.8 mm screen, sized to 20 to 32 mesh, and dried at 30 ° C. to give granules.

Comparative Example 6 10 parts by weight of formalin condensate of sodium salt of naphthalene sulfonic acid, 10 parts by weight of clay and 30 parts by weight of water were added to 80 parts by weight of raw material of difortan pulverized in advance and kneaded, and an extrusion type with a 0.8 mm screen attached Granulated with a granulator, sized to 20 to 32 mesh, and dried at 30 ° C to give granules.

De ^0.70 × P in the above Examples 1 to 6 and Comparative Examples 1 to 3
^{The values of −0.40} × μ ^0.22 × σ ^0.60 are shown in Table 1.

With respect to Examples 1 to 6 and Comparative Examples 1 to 6, self-dispersibility, hydration property, and suspension stability were evaluated as follows. The results are shown in Table 2 together with the particle size, bulk density, and presence or absence of powdering.

Evaluation of self-dispersibility (disintegration) 125 ml of 3 times hard water is put into a 250 ml stoppered cylinder, and 1.2 g of the sample prepared by the above method is gently added.

At the same time as observing the self-dispersing property, the number of falls in which the charged particles are all collapsed and dispersed is counted by the method of inverting the capped cylinder once every 2 seconds.

The evaluation criteria for self-dispersibility are as follows.

4 Immediately disperses without forming secondary aggregates.

3 No secondary agglomerates are formed, but 50% of the input particles are not dispersed.

2 Secondary aggregates do not form, but 80% or more of the input particles do not disperse.

1 Agglomeration between particles occurs and 100% of input particles are not dispersed.

Put 100 ml of hard water 3 times into a beaker of 100 ml of hydratability, gently add 1.0 g of the sample prepared by the above method, and measure the time until the powder or granules sink.

Suspension stability evaluation A sample is precisely weighed in a beaker, and 50 ml of 3 times hard water at 20 ° C is added and well mixed and dispersed. Transfer it to a 250 ml cylinder with a stopper, add 3 times hard water at 20 ° C. to make 250 ml, let stand for 15 minutes, shake vigorously 30 times for 1 minute, and let stand for 5 minutes. Next, put a 25 ml hole pipette in the liquid, keep the tip in the center of the liquid, gently take 25 ml of the test liquid, filter with a glass filter, dry the residue at 105 ° C for 4 hours, and suspend it from the following formula. Find the rate.

A: Weight of sample weighed first statically B: Weight of dry residue of collected test solution

Claims (1)

[Claims] 1. A method for producing a granular pesticide, which comprises subjecting a concentrated dispersion slurry containing a water-insoluble pesticide powder to countercurrent spray drying under the following conditions (i) and (ii). (I) 6.8 ≦ de ^0.70 × P ^−0.40 × μ ^0.22 × σ ^0.60 (Ii) spray nozzle diameter 0.5 to 4.0 mm, spray pressure 5~250kg / cm ² (pressure nozzle) hot air inlet temperature of 150 to 300 ° C. exhaust air temperature 60 to 120 ° C.