JPH0899805A - Production of agrochemical made into microcapsule - Google Patents

Abstract

PURPOSE: To provide a method for producing an agrochemical made into a microcapsule, capable of readily making even a solid agrochemical active ingredient slightly soluble in an organic solvent into a microcapsule. CONSTITUTION: An agrochemical active ingredient solid at a normal temperature, having preferably >=50 deg.C melting point, dispersible into a water-immiscible liquid such as an organic solvent without being dissolved, is suspended in a water-immiscible liquid. The prepared suspension as liquid drops is dispersed into water and films are formed in the circumference of the liquid drops by a common microcapsule forming method such as interface polymerization method or in-situ polymerization method. In suspending the solid agrochemical active ingredient in a water immiscible liquid, the concentration of solid component is made preferably <=45wt.%. An aliphatic hydrocarbon, an aromatic hydrocarbon, an alcohol, a ketone, an ester or an ether may be cited as the water- immiscible liquid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for microencapsulating a pesticide active ingredient which is solid at room temperature.

[0002]

2. Description of the Related Art Conventionally, it has been known that by encapsulating a pesticidal active ingredient in microcapsules, a pesticidal preparation having various properties can be obtained. Generally, a solid pesticide active ingredient is microencapsulated. Uses a microencapsulation method in which, as a liquid substance dissolved in a water-immiscible liquid such as an organic solvent, the liquid substance is dispersed in water as droplets to form a film around the droplets. .

[0003]

However, it is difficult to microencapsulate a solid agricultural chemical active ingredient which is hardly soluble in an organic solvent or the like by such a method.

[0004]

The present invention is capable of easily microencapsulating a solid agricultural chemical active ingredient which is poorly soluble in an organic solvent, etc., and the solid agricultural chemical active ingredient is solid at room temperature in a water immiscible liquid. The present invention provides a method for producing a microencapsulated pesticide, in which the resulting suspension is dispersed as droplets in water and then a film is formed around the droplets. Further, in the production method, when the solid pesticide active ingredient is suspended in a water-immiscible liquid, the solid content concentration is adjusted to 45% by weight or less, which is more advantageous in the production of the microencapsulated pesticide. Become.

Since the pesticidal active ingredient used in the present invention needs to be suspended in a water-immiscible liquid, it is solid at room temperature, preferably has a melting point of 50 ° C. or higher,
A substance that can be dispersed without being dissolved in a water-immiscible liquid such as an organic solvent is used. Of course, even if the pesticidal active ingredient is easily soluble in a certain organic solvent, the production method of the present invention can be carried out by appropriately selecting and dispersing the kind of water-immiscible liquid.

Specific examples of the agricultural chemical active ingredient used in the present invention include methoxadiazone {5-methoxy-3.
-(2-Methoxyphenyl) -1,3,4-oxadiazol-2 (3H) -one}, diniconazole {(E)
-1- (2,4-Dichlorophenyl) -4,4-dimethyl-2- (1H-1,2,4-triazol-1-yl) pent-1-en-3-ol}, procymidone {N- ( 3,5-dichlorophenyl) -1,2-dimethylcyclopropane-1,2-dicarboximide}, oxophosphoric acid {5-ethyl-5,8-dihydro-8-oxo [4,5-g] quinoline-7 -Carboxylic acid}, bromobutide {2-bromo-N- (α, α-dimethylbenzyl) -3,3-dimethylbutanamide}, flumicrolac-pentyl {pentyl 2-chloro-4-fluoro-5- (3 , 4,5,6-Tetrahydrophthalimide)
Phenoxyacetate}, uniconazole {(E) -1
-(4-chlorophenyl) -4,4-dimethyl-2-
(1H-1,2,4-triazol-1-yl) pent-1-en-3-ol}, tetramethrin {3,4
5,6-Tetrahydrophthalimidomethyl chrysanthemate}, resmethrin {5-benzyl-3-furylmethyl chrysanthemate}, dioxabenzophos {2-
Methoxy-4H-benzo-1,3,2-dioxaphosphorin-2-sulfide}, xylylcarb {3,4-xylylmethylcarbamate}, tolclofos-methyl {O- (2,6-dichloro-4-methylphenyl)
O, O-dimethyl phosphorothioate}, dimethoate {O, O-dimethyl S-methylcarbamoylmethyl
Phosphorodithioate}, dietofencarb {isopropyl 3,4-diethoxycarbanilate} and the like.

The water-immiscible liquid used in the present invention is appropriately selected according to the kind of the agrochemical active ingredient, which can disperse the agrochemical active ingredient with little dissolution. Aliphatic hydrocarbons, aromatic hydrocarbons such as phenylxylylethane, alcohols such as hexanol and octanol, ketones such as diisobutyl ketone, 2-ethylhexyl acetate, dibutyl maleate, esters such as diisodecyl adipate, Examples thereof include ethers such as 2-ethylhexyl ether, mineral oils such as machine oil, vegetable oils such as cottonseed oil and the like, and mixtures thereof. The solubility of the agricultural chemical active ingredient in the water-immiscible liquid is preferably 5% by weight or less.

The general manufacturing method of the present invention will be described in more detail below. First, the pesticidal active ingredient is finely pulverized in a water immiscible liquid to obtain a suspension, or the pesticidal active ingredient previously finely pulverized is dispersed in a water immiscible liquid to obtain a suspension. Attritor (Mitsui Miike Kakoki Co., Ltd.), Dyno Mill (Shinmaru Enterprises Co., Ltd.), Colloid Mill (Tokushu Kika Kogyo Co., Ltd.) are used when finely pulverizing pesticide active ingredients in a water-immiscible liquid to obtain a suspension. , A pearl mill (manufactured by Ashizawa Iron Works) or the like is used. Further, when a finely pulverized pesticide active ingredient is dispersed in a water-immiscible liquid to obtain a suspension, dry pulverization such as an atomizer (manufactured by Fuji Paudal) or a jet ohmizer (manufactured by Seishin Enterprise) is used. Machine is used.

When obtaining a suspension as described above, fatty acid soaps, ether carboxylates, salts of condensates of higher fatty acids and amino acids, higher alkyl sulfonates, α-olefin sulfonates are used as auxiliary agents. Salt, sulfonate of higher fatty acid ester, dialkyl sulfosuccinate, sulfonate of higher fatty acid amide, alkylaryl sulfonate, higher alcohol sulfate ester salt, alkyl ether sulfate ester salt, alkylaryl ether sulfate ester salt, higher salt Sulfate of fatty acid ester, sulfate of higher fatty acid alkylolamide, sulfated oil,
Anionic surfactants such as phosphate salts, polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, formalin condensates of polyoxyethylene alkylphenols, polyoxyethylene fatty acid esters, polyoxyethylenated oils and fats, polyoxyethylenated A wax, a polyhydric alcohol ester, a nonionic surfactant such as polyoxyethylene polyoxypropylene block copolymer, a thickener such as silicic acid anhydride, and organically modified montmorillonite may be added.

When the obtained suspension is dispersed in water as a droplet, a stirrer such as a propeller stirrer, a turbine stirrer and a high speed shear mixer is used, and the suspension is usually dispersed as fine droplets. . The particle size of the obtained microcapsules can be adjusted by changing the stirring conditions at this time, and the film of the obtained microcapsules can be adjusted by adjusting the amount of the film-forming substance used thereafter. The thickness can be adjusted.

When the droplets of the suspension are dispersed in water,
It is preferable to add a dispersant in water in advance. As the dispersant used, gelatin, gum arabic, casein, dextrin, pectin, sodium alginate,
Methylcellulose, ethylcellulose, sodium carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, sodium polyacrylate, polyvinyl alcohol, polyvinylpyrrolidone, water-soluble polymer such as carboxyvinyl polymer, fatty acid soap, ethercarboxylic acid, ethercarboxylic acid salt,
Salts of condensates of higher fatty acids and amino acids, higher alkyl sulfonates, α-olefin sulfonates, higher fatty acid ester sulfonates, dialkylsulfosuccinates, higher fatty acid amide sulfonates, alkylaryl sulfonic acids Salt, higher alcohol sulfate ester salt, alkyl ether sulfate ester salt, alkylaryl ether sulfate ester salt, sulfate ester salt of higher fatty acid ester, sulfate ester salt of higher fatty acid alkylolamide,
Anionic surfactants such as sulfated oil and phosphate ester salts, alkylamine salts, amine salts of polyamines or aminoalcohol fatty acid derivatives, alkyl quaternary ammonium salts, cyclic quaternary ammonium salts, and quaternary ammonium salts having a hydroxyl group. , Cationic surfactants such as quaternary ammonium salts having an ether bond, amphoteric surfactants such as carboxylic acid type, sulfuric acid ester type, sulfonic acid type and phosphoric acid ester type, polyoxyethylene alkyl ether, polyoxyethylene alkyl Nonionic surfactants such as aryl ethers, formalin condensates of polyoxyethylene alkylphenols, polyoxyethylene fatty acid esters, polyoxyethyleneized oils and fats, polyhydric alcohol esters, polyoxyethylene polyoxypropylene block copolymers, etc. It is.

In order to form a film around the droplet, a usual microencapsulation method such as an interfacial polymerization method or an in-situ polymerization method is used. In order to carry out the microencapsulation method by the interfacial polymerization method, a polyvalent isocyanate (for example, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, phenylene) is previously added to the suspension of the agricultural chemical active ingredient. Diisocyanate, toluene diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, polymethylene polyphenyl diisocyanate), polyvalent carboxylic acid chloride (for example, sebacic acid dichloride, adipic acid dichloride, azelaic acid dichloride, terephthalic acid) A film-forming raw material for forming a microcapsule such as dichloride, trimesic acid dichloride) or polyvalent sulfonyl chloride (for example, benzenesulfonyl dichloride) is added in advance in water in which the droplets of the suspension are dispersed, if necessary. Add a water-soluble film-forming raw material such as polyhydric alcohol (eg, ethylene glycol, butanediol, hexanediol), polyvalent amine (eg, ethylenediamine, hexamethylenediamine, phenylenediamine, diethylenetriamine, triethylenetetramine, piperazine). Keep it. The film forming reaction is usually carried out within a temperature range of 0 to 80 ° C., preferably 40 to 80 ° C. for about 0.5 to 48 hours, and a catalyst can be used to accelerate the reaction. In this way, a film of polyurethane, polyurea, polyamide, polyester, polysulfonate, polysulfonamide or the like is formed.

To carry out the microencapsulation method by the in-situ polymerization method, a water-soluble prepolymer such as aminoplast, urea formalin condensate, and melamine formalin condensate is added in advance to the water in which the droplets of the suspension are dispersed. Then, the mixture is heated to 40 to 80 ° C. under agitation for 0.5 to 4
It can be performed by holding for about 8 hours.

The microencapsulated pesticide slurry thus produced can be used as it is as a pesticide, but it is usually an aqueous suspension containing a thickener, an antifreezing agent, a preservative, a specific gravity adjusting agent and the like. Used as a clouding agent. As the thickener, xanthan gum, rhamsan gum, locust bean gum, carrageenan, natural polysaccharides such as wellant gum, synthetic polymers such as sodium polyacrylate, semi-synthetic polymers such as carboxymethyl cellulose, aluminum magnesium silicate, smectite, bentonite, Hectorite, mineral powder such as fumed silica, alumina sol and the like can be mentioned. Examples of the antifreezing agent include propylene glycol and the like. As a preservative, p
Examples thereof include hydroxybenzoic acid ester and salicylic acid derivatives. Specific gravity adjusting agents include water-soluble salts such as sodium sulfate and water-soluble fertilizers such as urea. It can also be used as a powdered preparation by a technique such as spray drying.

The content of the pesticidal active ingredient when formulated into an aqueous suspension or powdery preparation is usually 0.1 to 40 of the total preparation.
% By weight, usually 0.1 to 0.1, especially in the case of aqueous suspensions.
It is 20% by weight.

[0016]

【Example】

Production Example 1 To a mixed solution of 100 g of phenylxylylethane and 100 g of diisodecyl adipate, 100 g of diniconazole was added and finely pulverized with a bead mill to obtain a solid content concentration of about 31% by weight.
Suspension. To this, 25 g of Sumidule L-75 (Sumitomo Bayer Urethane Aromatic Isocyanate) was added, added to 500 g of water containing 30 g of gum arabic and 20 g of ethylene glycol, and added with T.I. K. The mixture was stirred at room temperature with an auto homomixer (homogenizer manufactured by Tokushu Kika Kogyo) to obtain fine droplets. Then, the mixture was stirred at 60 ° C. for 24 hours to obtain a slurry in which diniconazole suspended in a mixed liquid of phenylxylylethane and diisodecyl adipate was microencapsulated with a polyurethane film. 175 g of water containing 1 g of xanthan gum and 5 g of aluminum magnesium silicate in this slurry
Was added to obtain 10% by weight of a diniconazole composition.

Production Example 2 200 g of phenylxylylethane and 50 g of bromobutide
Was added and finely pulverized with a bead mill to obtain a suspension having a solid content concentration of about 19% by weight. In addition to this, Sumidur L-75
The mixture obtained by adding 10 g to 500 g of water containing 30 g of gum arabic and 20 g of ethylene glycol was added to T.I. K.
The mixture was stirred at room temperature with an auto homomixer to obtain fine droplets.
Then, by stirring at 60 ° C. for 24 hours, a slurry in which bromobutide suspended in phenylxylylethane was microencapsulated with a polyurethane film was obtained.
To this slurry was added 240 g of water containing 1 g of xanthan gum and 5 g of aluminum magnesium silicate, and 5
A wt% bromobutide composition was obtained.

Production Example 3 To a mixed solution of 100 g of phenylxylylethane and 100 g of diisodecyl adipate, 100 g of diniconazole was added and finely pulverized with a bead mill to obtain a solid content of about 31% by weight.
Suspension. To this, Sumidur L-75 25
g was added to water 490 containing gum arabic 30 g
g., T. K. The mixture was stirred at room temperature with an auto homomixer to obtain fine droplets. Then, by stirring at 60 ° C. for 24 hours, the diniconazole suspended in the mixed liquid of phenylxylylethane and diisodecyl adipate was
A slurry microencapsulated with a polyurea film was obtained. To this slurry was added 185 g of water containing 1 g of xanthan gum and 5 g of aluminum magnesium silicate to obtain a 10 wt% diniconazole composition.

Production Example 4 Proisomidone 100 to 200 g of diisodecyl adipate
g and pulverized with a bead mill to obtain a solid content of about 30
The suspension was a weight%. In addition to this, Sumidur L-75
What added 25 g was added to 325 g of water containing 30 g of gum arabic and 20 g of ethylene glycol, and T.I.
K. The mixture was stirred at room temperature with an auto homomixer to obtain fine droplets. Then, by stirring at 60 ° C. for 24 hours, the procymidone suspended in diisodecyl adipate was
A slurry microencapsulated with a polyurethane membrane was obtained. 350 g of water containing 1 g of xanthan gum and 5 g of aluminum magnesium silicate was added to this slurry to obtain a 10% by weight procymidone composition.

Production Example 5 To a mixed solution of 150 g of phenylxylylethane and 50 g of diisodecyl adipate, 100 g of diniconazole was added and finely pulverized with a bead mill to obtain a suspension having a solid content concentration of about 32% by weight. To this, Sumidur L-75 50g
Was added to 530 g of water containing 30 g of gum arabic and 30 g of ethylene glycol, and T.I. K. The mixture was stirred at room temperature with an auto homomixer to obtain fine droplets. Then, the mixture was stirred at 60 ° C. for 24 hours to obtain a slurry in which diniconazole suspended in a mixed liquid of phenylxylylethane and diisodecyl adipate was microencapsulated with a polyurethane film. In this slurry,
120 g of water containing 1 g of xanthan gum and 5 g of aluminum magnesium silicate was added to obtain a 10% by weight diniconazole composition.

Production Example 6 Procymidone (100 g) was added to a mixed solution of 100 g of phenylxylylethane and 100 g of diisodecyl adipate and finely pulverized with a bead mill to obtain a suspension having a solid content concentration of about 30% by weight. To this, Sumidur L-75 25g
Was added to 500 g of water containing 15 g of polyvinyl alcohol and 20 g of ethylene glycol, and T.I.
K. The mixture was stirred at room temperature with an auto homomixer to obtain fine droplets. Then, the mixture was stirred at 60 ° C. for 24 hours to obtain a slurry in which procymidone suspended in a mixed liquid of phenylxylylethane and diisodecyl adipate was microencapsulated with a polyurethane film. 175 g of water containing 1 g of xanthan gum and 5 g of aluminum magnesium silicate was added to this slurry to obtain a 10% by weight procymidone composition.

[0022]

According to the method for producing a microencapsulated pesticide of the present invention, even a solid pesticide active ingredient which is hardly soluble in an organic solvent or the like can be easily microencapsulated.

Claims (2)

[Claims] 1. A pesticide active ingredient, which is solid at room temperature, is suspended in a water-immiscible liquid, the resulting suspension is dispersed as droplets in water, and then a film is formed around the droplets. And a method for producing a microencapsulated pesticide. 2. A pesticidal active ingredient which is solid at room temperature is suspended in a water immiscible liquid so that the solid content concentration is 45% by weight or less, and the resulting suspension is dispersed in water as droplets, Next, a method for producing a microencapsulated pesticide, which comprises forming a film around the droplet.