GB2187957A - Microencapsulated pyrethroid insecticidal and/or acaricidal composition - Google Patents

Microencapsulated pyrethroid insecticidal and/or acaricidal composition Download PDF

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GB2187957A
GB2187957A GB8706188A GB8706188A GB2187957A GB 2187957 A GB2187957 A GB 2187957A GB 8706188 A GB8706188 A GB 8706188A GB 8706188 A GB8706188 A GB 8706188A GB 2187957 A GB2187957 A GB 2187957A
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resins
reactant
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GB2187957B (en )
GB8706188D0 (en )
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Kiyoshi Kasamatsu
Yukio Manabe
Toshiro Ohtsubo
Hisami Takeda
Shigenori Tsuda
Kozo Tsuji
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Sumitomo Chemical Co Ltd
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Sumitomo Chemical Co Ltd
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/02Making microcapsules or microballoons
    • B01J13/06Making microcapsules or microballoons by phase separation
    • B01J13/14Polymerisation; cross-linking
    • B01J13/16Interfacial polymerisation
    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01NPRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES, AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N25/00Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
    • A01N25/26Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests in coated particulate form
    • A01N25/28Microcapsules or nanocapsules
    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01NPRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES, AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N53/00Biocides, pest repellants or attractants, or plant growth regulators containing cyclopropane carboxylic acids or derivatives thereof

Abstract

A microencapsulated pyrethroid insecticidal and/or acaricidal composition, e.g. for agricultural uses, comprises at least one pyrethroid compound encapsulated in a wall of a synthetic polymer and has an average particle diameter of not more than 80 micrometers, wall thickness of not more than 0.3 micrometer, and average particle diameter/wall thickness ratio of not less than 250. It exhibits a good residual efficacy and reduced fish toxicity.

Description

SPECIFICATION Microencapsulated pyrethroid insecticidal and/or acaricidal composition for agricultural uses The present invention relates to a microencapsulated pyrethroid insecticidial and/or acaricidal composition for agricultural uses which comprises at least one of pyrethroid compounds encapsulated in a wall formed of a synthetic polymer and having an average particle diameter of not more than 80 micrometers, wall thickness of not more than 0.3 micrometer, and average particle diameter/wall thickness ratio of not less than 250, whereby an excellent residual effect is exhibited. The invention also relates to a method for producing the same and a method of use thereof.

In general, pyrethroid insecticides and/or acaricides have high immediate insecticidal and/or acaricidal efficacies. They are prepared into formulations such as an emulsifiable concentrate, an oil, a wettable powder, a dust and the like and are now in use as agricultural insecticides and/or acaricides. As the residual efficacy of most pyrethroid insecticides and/or acaricides is low and the cost is high, it has been expected to find out a more economical method of use.

Generally, many of the pyrethroid insecticides and/or acaricides exhibit a relatively high fish toxicity, and when they are prepared into ordinary formulations such as an emulsifiable concentrate, an oil, a wettable powder and a dust, it may be difficult to lower the fish toxicity. Thus, there is a demand of the development of a formulation for reducing a fish toxicity.

When insecticides and/or acaricides are microencapsulated with a wall of a synthetic polymer, active ingredients are isolated from the environment outside of the wall. So, they are protected from the decomposition by some factors such as microorganism, moisture and light. The release rate of the active ingredient through the wall is controlled when the active ingredient is encapsulated. For the above two reasons, microencapsulated insecticides and/or acaricides have, in most cases, a better residual efficacy. For instance, Japanese Patent Publication No. 55-38235 which relates to a pyrethroid insecticidal composition which is obtained by encapsulating a pyrethroid insecticide with a polyurethane resin, discloses that such microencapsulation results in a better residual effect.

As will be seen from the above, the microencapsulation of insecticides and/or acaricides will frequently tend to give a good residual efficacy.

However, even though the same insecticide or acaricide is encapsulted with the same wall material, it is not always expected to keep a given degree of the residual effect. In fact, it has been experienced that the degree of the residual efficacy differs among microcapsules.

The microencapsulation has the general tendency toward the lowering of fish toxicity of insecticides and/or acaricides, but the lowering rate has often been found to vary among microcapsules.

The present inventors made intensive studies and, as a result, found that various factors concerned with microcapsules, particularly a particle diameter and a wall thickness of the microcapsule, gave a great influence on the residual efficacy and the degree in reduction of fish toxicity. The present invention is accomplished on the basis of the above finding.

More particularly, the present inventors made intensive studies on conditions to give good residual efficacy in microencapsulation of pyrethroid insecticides and/or acaricides with synthetic polymers. As a result, it is found the residual efficacy becomes especially high when pyrethroid insecticides and/or acaricides are microencapsulated with synthetic polymers in such a way that an average particle diameter of microcapsules is not more than 80 micrometers, wall thickness of the microcapsule is not more than 0.3 micrometer, and a ratio of average particle diameter/ wall thickness is not less than 250. In addition, such microcapsules have lower fish toxicity.

For the microencapsulation, an interfacial polymerization method is convenient for its simplicity in which an oil-soluble reactant A is added to an oil phase containing a pyrethroid insecticide and/or acaricide and is then dispersed in an aqueous phase, and then a reactant B capable of forming a polymer by reaction with the reactant A is added to the aqueous phase, thereby forming a wall at the interface between both phases. Alternatively, the pyrethroid insecticide and/or acaricide-containing oil phase, to which the reactant A has been added, may be dispersed in an aqueous phase to which the reactant B has been previously added, followed by wall formation at the interface. Of course, when the wall is synthesized only by reaction of the reactant A in the oil phase and water, it is no need to add the reactant B.If necessary, the oil phase may contain organic solvent which is almost immisible with water in addition to the reactant A and the pyrethroid insecticide and/or acaricide. In this case, the mixture of the reactant A, the pyrethroid insecticide and/or acaricide and the solvent is demanded to be uniform. The organic solvents used for this purpose among ordinary solvents include, for example, hydrocarbons such as xylene, toluene, alkylbenzenes, phenylxylylethane, hexane, heptane and the like, chlorinated hydrocarbons such as chloroform, ketones such as methyl ethyl ketone and cyclohexanone and the like, and esters such as diethyl phthalate and n-butyl acetate and the like.

The method of the microencapsulation using the interfacial polymerization is described.

1. Encapsulation of pyrethroid insecticides and/or acaricides with polyurethane resins: (1) A solution containing at least one of pyrethroid insecticides and/or acaricides and a polyfunctional isocyanate compound having at least two isocyanate groups is dispersed in an aqueous solution containing a dispersing agent and polyhydric alcohol having at least two hydroxyl groups, followed by an interfacial polymerization.

(2) A solution containing at least one of pyrethroid insecticides and/or acaricides and a polyfunctional isocyanate compound having at least two isocyanate groups is dispersed in an aqueous solution containing a dispersing agent, to which polyhydric alcohol having at least two hydroxyl groups is added, followed by an interfacial polymerization.

2. Encapsulation of pyrethroid insecticides and/or acaricides with polyrea resins: (1) A solution containing at least one of pyrethroid insecticides and/or acaricides and a polyfunctional isocyanate compound having at least two isocyanate groups is dispersed in an aqueous solution containing a dispersing agent with or without polyfunctional amine having at least two amino groups, followed by an interfacial polymerization.

(2) A solution containing at least one of pyrethroid insecticides and/or acaricides and a polyfunctional isocyanate compound having at least two isocyanate groups is dispersed in an aqueous solution containing a dispersing agent, followed by an interfacial polymerization after addition of polyfunctional amine having at least two amino groups to the dispersed solusion.

3. Encapsulation of pyrethroid insecticides and/or acaricides with polyamide resins: A mixture of at least one of pyrethroid insecticides and/or acaricides and polyfunctional acid chloride having at least two COCI groups is dispersed in an aqueous solution containing a dispersing agent, and a polyfunctional amine having at least two amino groups is added to the dispersed solusion, followed by an interfacial polymerization.

4. Encapsulation of pyrethroid insecticides and/or scaricides with polyamide-polyurea resins: A mixture of (1) a mixture of at least one of pyrethroid insecticides and/or acaricides and polyfunctional acid chloride having at least two COCI groups and of (2) polyfunctional isocyanate having at least two NCO groups is dispersed in an aqueous solution containing a dispersing agent, and polyfunctional amine having at least two amino groups is added to the dispersed solusion, followed by an interfacial polymerization.

5. Encapsulation of pyrethroid insecticides and/or acaricides with polyester resins: A mixture of at least one of pyrethroid insecticides and/or acaricides and polyfunctional acid chloride havin at least two COCI groups is dispersed in an aqueous solution containing a dispersing agent, and polyhydric alcohol having at least two hydroxyl groups is added to the dispersed solution, followed by an interfacial polymerization.

6. Encapsulation of pyrethroid insecticides and/or acaricides with polycarbonate resins: A mixture of at least one of pyrethroid insecticides and/or acaricides and phosgene is dispersed in an aqueous solution containing a dispersing agent, and polyhydric alcohol having at least two hydroxyl groups is added to the dispersed solution, followed by an interfacial polymerization.

7. Encapsulation of pyrethroid insecticides and/or acaricides with polysulfonate resins: A mixture of at least one of pyrethroid insecticides and/or acaricides and polyfunctional sulfonyl chloride having at least two SO2Cl groups is dispersed in an aqueous solution containing a dispersing agent, polyhydric alcohol having at least two hydroxyl groups is added to the dispersed solution, followed by an interfacial polymerization.

8. Encapsulation of pyrethroid insecticides and/or acaricides with polysulfoneamide resins: A mixture of at least one of pyrethroid insecticides and/or acaricides and polyfunctional sulfonyl chloride having at least two SO2CI groups is dispersed in an aqueous solution containing a dispersing agent, and polyfunctional amine having at least two amino groups is added to the dispersed solution, followed by an interfacical polymerization.

9. Encapsulation of pyrethroid insecticides and/or acaricides with epoxy resins: A mixture of at least one of pyrethroid insecticides and/or acaricides and polyfunctional epoxy compound having at least two epoxy rings is dispersed in an aqueous solution containing a dispersing agent, and polyfunctional amine having at least two amino groups is added to the dispersed solution, followed by an interfacial polymerization.

The suspension of microcapsules obtained after the encapsulation reaction may be used as it is or after dilution with water to a given concentration. In practice, it is preferred that the suspension or its dilution is mixed with a thickening agent for use as a stable slurry-type formulation.

If an excess of amine is sused for the polymerization, it may be neutralized, for example, with hydrochloric acid after the reaction.

The reaction period of time may vary depending on the type of the reactant and the reaction temperature and is preferably not shorter than 1 hour.

When the solution containing at least one of pyrethroid insecticides and/or acaricides (herein after referred to simply as "oil phase") is dispersed in an aqueous solution containing a dispersing agent and the like (hereinafter referred to simply as "aqueous phase"), either a batchwise dispersing machine or a continuous feed-type dispersing machine may be used. The ratio of the oil phase to the aqueous phase at the time of the dispersion should preferably be at most 2:1. If the amount of the oil phase exceeds the above range, there is a great possibility that no oil-in-water type dispersion system required for the microencapsulation reaction is obtained, but a water-in-oil type dispersion system.

The conditions for obtaining microcapsules having an average particle diameter of not more than 80 micrometers, a wall thickness of not more than 0.3 micrometer and a value of average particle diameter/wali thickness of not less than 250 are described, referring to encapsulation of pyrethroid insecticides and/or acaricides with polyurethane resins or polyurea resins. These conditions are fundamentally the same as for microencapsulation with other types of resins.

An amount of polyhydric alcohol necessary for microencapsulation with polyurethane resin is at least WNco.NNco MOH x- parts by weight MNCO NOH wherein WNCO: amount of a polyfunctional isocyanate compound to be charged into an oil phase (parts by weight); NNCO: number of isocyanate groups contained in one molecule of polyfunctional isocyanate compound above; MNCO: molecular weight of polyfunctional isocyanate compound above; MoH : molecular weight of polyhydric alcohol; Now : number of hydroxyl group in one molecule of the polyhydric alcohol.

An amount of polyfunctional amine necessary for microencapsulation with polyurea resin is at least W NcONNco MNH2 x parts by weight mNCO NNH2 wherein WNCO. NNCO and MNCO: same as above; MNH2 . molecular weight of polyfunctional amine; NNH2 : number of amino groups in one molecule of the polyfunctional amine.

In case where a polyfunctional isocyanate compound reacts with water to form a polyurea resin, all necessary is to use an enough water to have the oil phase dispersed therein.

The wall thickness (T) of the microcapsule is proximately expressed by the following equation (I): Ww Pc d (T)=-. -. - Wc Pw 6 wherein Ww : amount of a wall material (see Note); Wc : amount of a core substance, parts by weight; which equals to Woil-WNCO where WO,l=am- ount of the oil phase to be charged at the time of the production of microcapsules; WNCO: defined above; Pc : density of the core substance; Pw : density of the wall material; d : average particle diameter of microcapsules.

Note: (1) When a polyurethane wall is formed by reaction between a polyfunctional isocyanate compound and a polyhydric alcohol, WNCO.NNCO MOH Ww = WNCO + MNCO NOH (2) When a polyurea wall is formed by reaction between a polyfunctional isocyanate compound and a polyfunctional amine, WNco'NNco MNH2 WW=WNCO+ MNCO NNH2 (3) When a polyurea wall is formed by reaction between a polyfunctional isocyanate compound and water, 2 moles of the isocyanate groups react with 1 mole of H20 to produce 1 mole of the urea bond with 1 mole of CO2 being evolved. Since the molecular weights of H20 and CO2 are 18 and 44, respectively, WNCO.NNCO (18-44) WW=WNCO+ .

MNCO 2 Accordingly, the proximate equation (I) can be rewritten as follows.

(1) When a polyurethane wall is formed by reaction between a polyfunctional isocyanate compound and a polyhydric alcohol, the following proximate equation (II) is obtained: NNCO#.MOH #c d WNCO ( 1 + ) - MNco-NoH Pw 6 Wall thickness (T)= WOjl WNCO (2) When a polyurea wall is formed by reaction between a polyfunctional isocyanate compound and a polyfunctional amine, the following proximate equation (III) is obtained:: NNCO.MNH2 #c d WNCO ( 1 + ) - MNCO.NNH2 #w 6 Wall thickness (T,)= Woil - WNCO (3) When a polyurea wall is formed by reaction between a polyfunctional isocyanate compound and water, the following proximate equation (IV) is obtained: 13NCO #c d WNCO (1- ) .

MNCO #w 6 Wall thickness (T3)= Woil - WNCO The term "wall thickness" used herein means thickness which has been calculated according to the proximate equation (11), (III) or (IV).

In order to produce microcapsules having an average particle diameter of not more than 80 micrometers, wall thickness of not more than 0.3 micrometer and a value of average particle diameter/wall thickness of not less than 250, the production conditions should be determined as follows: (1) d#80 micrometers, T1#0.3 micrometer and d/T1#250 for the formation of a polyurethane wall by reaction between a polyfunctional isocyanate compound and a polyhydric alcohol; (2) d#80 micrometers, T2#0.3 micrometer and d/T2#250 for the formation of a polyurea wall by reaction between a polyfunctional isocyanate compound and a polyfunctional amine; and (3) d#80 micrometers, T3#0.3 micrometer and d/T3#250 for the formation of a polyurea wall by reaction between a polyfunctional isocyanate compound and water.

The average particle diameter of microcapsules is determined depending mainly on the type and concentration of a dispersing agent used for the dispersion and also on the degree of mechanical agitation during the dispersion. For the measurement of the average particle diameter, the Coulter counter Model TA-II, (available from Nikkaki) may be used, for example.

The polyfunctional isocyanates used for the microencapsulation include, for example, toluene diisocyanate, hexamethylene diisocyanate, adducts of toluene diisocyanate and trimethylolpropane, self-condensates of hexamethylene diisocyanate, SUMIDUR LR (made by Sumitomo-Bayer Urethane Co., Ltd.), SUMIDUR NR (made by Sumitomo-Bayer Urethane Co., Ltd.), and the like.

The polyhydric alcohols having at least two OH groups include, for example, ethylene glycol, propylene glycol, butylene glycol, hexanediol, heptanediol, dipropylene glycol, triethylene glycol, glycerine, resorcinol, hydroquinone, and the like.

The polyfunctional amines having at least two NH2 groups include, for example, ethylenediamine, hexamethylenediamine, phenylenediamine, toluenediamine, diethylenetriamine and the like.

The polyfunctional acid chlorides having at least two COCI groups include, for example, sebacoyl chloride, terphthaloyl chloride, trimesoyl trichloride and the like.

The polyfunctional sulfonyl chlorides having at least two SO2CI groups are, for example, phenylene-disulfonyl chloride and the like.

The polyfunctional epoxy compounds having at least two epoxy rings are, for example, epichlorohydrin and the like.

The dispersing agent for dispersing an oil phase which comprises pyrethroid insecticides and/or acaricides and polyfunctional reactants include, for example, one or more of natural polysaccharides such as gum arabic, semi-synthetic polysaccharides such as carboxymethyl cellulose, methyl cellulose and the like, synthetic polymers such as polyvinyl alcohol, polyvinyl pyrrolidone and the like, fine mineral powders such as magnesium.aluminium.silicate, and the like.

When the suspension dispersibility is weak, the suspension dispersibility may be improved by adding a known surfactant such as given in H. Horiguchi; "Synethetic Surface Active Agent".

If necessary, natural polysaccharides such as xanthan gum, locust bean gum and the like, semi-synthetic polysaccharides such as carboxymethyl cellulose, synthetic polymers such as sodium polyacrylate, fine mineral powders such as magnesium.aluminium.silicate and the like may be used, singly or in combination, as a thickening agent.

Examples of the pyrethroid insecticides and/or acaricides include fenvalerate (alpha-cyano-3phenoxybenzyl alpha-isopropyl-4'-chlorophenylacetate), fenpropathrin(alpha-cyano-3-phenoxybenzyl 2, 2,3,3,-tetramethylcyclopropanecarboxylate), permethrin[3-phenoxybenzyl 2,2-dimethyl-3-(2,2,-di chlorovinyl)-cyclopropane- 1 -carboxylate], cypermethrin[alpha-cyano-3-phenoxybenzyl 3-(2,2-dichlo rovinyl)-2,2-dimethylcyclopropanecarboxylate], tetramethrin (3,4,5,6-tetrahydrophthalimidomethyl chrysanthemate), allethrin (3-allyl-2-methylcyclopenta-2-ene-4-on-1-yl-cis, transcrysanthemate), phenothrin(3-phenyoxybenzyl cis, transchrysanthemate), deltamethrin[alpha-cyano-3-phenoxybenzyl 3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylate], cyhalothrin[alpha-cyano-3-phenoxybenzyl 2,2-dimethyl-3-(3 ,3 ,3-trifluoro-2-chloro-propenyl)-cyclopropane carboxylate] and isomers thereof, and natural pyrethrin. However, these compounds should not be construed as limiting the insecticides and/or acaricides of the invention thereto but are mentioned only as examples.

As a matter of course, mixtures of pyrethroid insecticides and/or acaricides and mixtures of pyrethroid insecticides and/or acaricides with other type of insecticides and/or acaricides may be used.

The composition of the invention may contain not only microcapsules formed of the same and one wall material, but also microcapsules formed of the other wall materials. In addition, different active ingredients may be contained in different microcapsules. If necessary, the composition of the invention may further contain a synergist such as piperonyl butoxide and a stabilizer ordinarily used for this purpose, e.g. BHT (2,6-di-t-butyl-4-methylphenol) or the like.

Insects or mites to be controiled according to the composition of the invention are those mentioned below: insects of Hemiptera order such as whitebacked planthopper (Sogatella furcifera), smaller brown planthopper (Laodelphax striatellus), brown rice planthopper (Nilaparvata lugens), green rice leafhopper (Nephotettix cincriceps), green peach aphid (Myzus persicae), cotton aphid (Aphis gossypli), cabbage aphid (Brevicoryne brassicae), greenhouse whitefly (Trialeurodes vaporariorum), and sweet potato whitefly (Bemisia abaci);; insects of Lepidoptera order such as tea leafroller (Caloptilia thoivora), apple leafminer (Phyllonorycter ringoneella), citrus leafminer (Phyllocnistis citrella), diamond-back moth (Plutella xylostella), summer fruit tortrix (Adoxophyes orana), oriental tea tortrix (Homona magnanima), rice stem borer (Chilo suppros salis), oriental corn borer (Ostrinia funacalis), rice leafroller (Cnaphalocrocis medThalls), common cutworm (Spodoptera litura), armyworm (Pseudaletia separata), american bollworm (Heliothis armigera), and pink bollworm (Pectiophora gossypiella); insects of Coleoptera order such as cupreous chafer (Anomala cuprea), soybean beetle (Anomala rufocuprea), Japanese beetle (Popillia japonica), cucurbit leaf beetle (Aulacophora femolalis), striped flea beetle (Phyllotreta striolata), rice plant weevii (Echinocnemus squameus), maize weevil (Sitophilus zeamais), and corn root worm (Diabrotica sp.); and mites (Acarina order), such as common spider mite (Tetranychus cinnabarinus), two-spotted spider mite (Tetranychus urticae), citrus red mite (Phanonychus citn), European red mite (Panonychus ulmi), cryptomeria spider mite (Oligonychus bondoensis), bull tick (Boopilus microplus), and two-spined tick (Haemaphysalis longicornis).

The present invention is described in more detail by way of examples. Comparative examples and test samples are also described.

Example 1 Four grams of "SUMIDUR" L@) (as indicated hereinbefore) and 100 g of phenylxylylethane (commercial name: "HISOL" SAS 2968, made by Nippon Petroleum Chemicals Co., Ltd.) were added to 1009 of fenvalerate and agitated until a uniform solution was obtained. This solution was added to 400 g of an aqueous solution of 10wt% of polyvinyl alcohol (commercial name "GOSENOL" GL-058, made by Nippon Gosei Kagaku K. K.) and the dispersion was carried out for several minutes by means of "T.K. autohomomixer" (commercial name, Tokushukika Kogyo K. K.) at room temperature until microdrops were formed. The number of revolutions was 1,250 r.p.m.

Thereafter, the dispersed solution was gently agitated at 60"C for 24 hours and a slurry of microencapsulated products was obtained.

Water was added to the slurry to make total weight of 1000 g, with the result that a slurry of fenvalerate microcapsules with polyurethane wall having an active ingredient concentration of 10 wt% (Composition 1).

The resultant microcapsules had an average particle diameter of 50 micrometers, wall thickness of 0.109 micrometer, and average particle diameter/wall thickness ratio of 459.

Example 2 The procedure of Example 1 was repeated except that the number of revolutions of "T.K.

autohomomixer" (as used above) was 6,500 r.p.m. in place of 1,250 r.p.m., thereby obtaining a slurry of fenvalerate microcapsules with polyurea wall having an active ingredient concentration of 10 wt% (Composition 2).

The resultant microcapsules had an average particle diameter of 5 micrometers, wall thickness of 0.011 micrometer and average particle diameter/wall thickness ratio of 455.

Example 3 The procedure of Example 1 was repeated except that the amount of "SUMIDUR" L8 (as indicated before) was changed to 0.8 g from 4 g and the number of revolutions of the "T.K.

autohomomixer" (as indicated before) was 6,500 r.p.m. in place of 1,250 r.p.m., thereby obtaining a slurry of fenvalerate microcapsules with polyurea wall having an active ingredient concentration of 10 wt% (Composition 3).

The resulting microcapsules had an average particle diameter of 5 micrometers, wall thickness of 0.002 micrometer and average particle diameter/wall thickness ratio of 2,500.

Example 4 The procedure of Example 1 was repeated except that the amount of "SUMIDUR" L8 (as indicated hereinbefore) was changed to 0.2 g from 4 g and the number of revolutions of "T.K.

autohomomixer" (as indicated hereinbefore) was 2,300 r.p.m. in place of 1,250 r.p.m., thereby obtaining a slurry of fenvalerate microcapsules with polyurea wall having an active ingredient concentration of 10 wt% (Composition 4).

The resulting microcapsules had an average particle diameter of 20 micrometers, wall thickness of 0.011 micrometer and average particle diameter/wall thickness ratio of 10,000.

Example 5 The procedure of Example 1 was repeated except that fenvalerate was replaced by fenpropathrin, and the number of revolutions of "T.K. autohomomixer" (as indicated hereinbefore) was 6,500 r.p.m. in place of 1,250 r.pm., thereby obtaining a slurry of fenpropathrin microcapsules with polyurea wall having an active ingredient concentration of 10 wt% (Composition 5).

The resulting microcapsules had an average particle diameter of 5 micrometers, wall thickness of 0.011 micrometer and average particle diameter/wall thickness ratio of 455.

Example 6 1.5 g of "SUMIDUR" L@) (as indicated hereinbefore) was added to 200 g of fenvalerate and the mixture was heated under agitation until a uniform solution was obtained. The solution was added to 350 g of an aqueous solution containing 5 wt% of gum arabic as a dispersing agent and the dispersion was carried out for several minutes by means of "T.K. autohomomixer" (as indicated hereinbefore) under heating. The number of revolutions was 8,500 r.p.m. Thereafter, the dispersed solution was gently agitated at 80"C for 20 hours and a slurry of microencapsulated products was obtained.

Water was added to the obtained slurry to make a total weight of 1000 g, thereby obtaining a slurry of fenvalerate microcapsules with polyurea wall having an active ingredient concentration of 20 wt% (Composition 6).

The resulting microcapsules had an average particle diameter of 15 micrometers, wall thickness of 0.013 micrometer and average particle diameter/wall thickness ratio of 1154.

Example 7 The procedure of Example 6 was repeated except that "SUMIDUR" L8 (as indicated hereinbefore) was used in an amount of 1 g in place of 1.5 g, 200 g of fenvalerate was replaced by 200 g of fenpropathrin, and the number of revolutions of "T.K. autohomomixer" (as used hereinbefore) was 5,500 r.p.m. in place of 8,500 r.p.m., thereby obtaining a slurry of fenpropa thrin microcapsules with polyurea wall having an active ingredient concentration of 20 wt% (Composition 7).

The thus obtained microcapsules had an average particle diameter of 50 micrometers, wall thickness of 0.03 micrometer, and average particle diameter/wall thickness ratio of 1,667.

Example 8 4 g of "SUMIDUR" L@) (as indicated hereinbefore) and 100 g of "HISOL" SAS-296 (as indicated hereinbefore) were added to 100 g of permethrin and the mixture was agitated until a uniform solution was obtained. The solution was added to 350 g of an aqueous solution containing 5 wt% of gum arabic as an dispersing agent and the dispersion was carried out for several minutes at room temperature by means of "T.K. autohomomixer" (as used before). The number of revolutions was 8,000 r.p.m. Thereafter the dispersed solution was gently agitated at 55 C for 30 hours and a slurry of microencapsulated products was obtained.

Water was added to the obtained slurry to make a total weight of 1000 g and 1000 g of aqueous solution containing 0.3 wt% of xanthan gum and 0.6 with of magnesium.aluminium.sili- cate as a thickening agent was added, thereby obtaining a permethrin microcapsule slurry with polyurea wall having an active ingredient concentration of 5 wt% (Composition 8).

The resulting microcapsules had an average particle diameter of 20 micrometers, wall thickness of 0.044 micrometer and average particle diameter/wall thickness ratio of 455.

Example 9 2 g of "SUMIDUR" L8 (as indicated hereinbefore) and 100 g of xylene were added to 100 g of cypermethrin and the mixture was agitated until a uniform solution was obtained. The solution was then added to 350 g of an aqueous solution containing 5 wt% of gum arabic as a dispersing agent and the dispersion was carried out under heating for several minutes by means of "T.K. autohomomixer" (as used hereinbefore). The number of revolutions was 5,500 r.p.m.

Thereafter, 6 g of ethylenediamine was added into the dispersed solution. Thereafter, the dispersed solution was gently agitated at 70"C for 24 hours and the slurry of microencapsulated products was obtained. A 1N hydrochloric acid aqueous solution was used to adjust the pH of the slurry to 7, after which water was added until a total weight was 1000 g, thereby obtaining a slurry of cypermethrin microcapsules with polyurea wall having an active ingredient concentration of 10 wt% (Composition 9).

The thus obtained microcapsules had an average particle diameter of 50 micrometers, wall thickness of 0.065 micrometer and average particle diameter/wall thickness ratio of 769.

Example 10 The procedure of Example 9 was repeated except that 2 g of "SUMIDUR" LR (as indicated hereinbefore) was replaced by 2 g of "SUMIDUR" N8 (as indicated hereinbefore), 100 g of cypermethrin was replaced by 100 g of tetramethrin, 6 g of ethylenediamine was replaced by 6 g of phenylenediamine, and the number of revolutions was 8,000 r.p.m., thereby obtaining a slurry of tetramethrin microcapsules with polyurea wall having an active ingredient concentration of 10 wt% (Composition 10).

The thus obtained microcapsules had an average particle diameter of 20 micrometers, wall thickness of 0.027 micrometer, and average particle diameter/wall thickness ratio of 741.

Example 11 1 g of "SUMIDUR" L8 (as indicated hereinbefore) and 50 g of xylene were added to 150 g of allethrin and the mixture was agitated until a uniform solution was obtained. The solution was then added to 350 g of an aqueous solution containing 5 wt% of gum arabic as a dispersing agent and the dispersion was carried out at room temperature for several minutes by means of "T.K. autohomomixer" (as used hereinbefore). The number of revolutions was 8,000 r.p.m.

Thereafter the dispersed solution and gently agitated at 60 C for 24 hours and the slurry of the microencapsulated products was obtained.

Water was added to the dispersion to make a total weight of 1000 g, followed by dilution to 1:2 with an aqueous solution of 4 wt% of carboxymethyl cellulose ("CELLOGEN" 3H8, made by Daiichi Kogyo Seiyaku K. K.), thereby obtaining a slurry of allethrin microcapsules with polyurea wall having an active ingredient concentration of 7.5 wt% (Composition 11).

The thus obtained microcapsules had an average particle diameter of 20 micrometers, wall thickness of 0.01 micrometer and average particle diameter/wall thickness ratio of 2000.

Example 12 The procedure of Example 6 was repeated except that "SUMIDUR" LR (as indicated hereinbefore) used singly was replaced by a mixture of 0.8 g of "SUMIDUR" LR (as indicated hereinbefore) and 0.1 g of toluene diisocyanate ("SUMIDUR" T808, made by Sumitomo Bayer Urethane Co., Ltd.), fenvalerate was replaced by phenothrin, and the number of revolutions of "T.K.

autohomomixer" (as used hereinbefore) was changed to 8,000 r.p.m. in place of 8,500 r.pm., thereby obtaining a slurry of phenothrin microcapsules with polyurea wall having an active ingredient concentraton of 20 wt% (Composition 12).

The thus obtained microcapsules had an average particle diameter of 20 micrometers, wall thickness of 0.01 micrometer, and average particle diameter/wall thickness ratio of 2,000.

Example 13 1 g of "SUMIDUR" L8 (as indicated hereinbefore) and 160 g fenitrothion [0,0-dimethyl-0-(3 methyl-4-nitrophenyl)phosphorothioate] were added to 40 g of fenvalerate and the mixture was agitated to obtain a uniform solution. The solution was added to 350 g of an aqueous solution containing 5 wt% of gum arabic and the dispersion was carried out for several minutes at room temperature by means of "T.K. autohomomixer" (as used before). The number of revolutions was 7,100 r.p.m. Thereafter the dispersed solution was gently agitated at 60"C for 24 hours and the slurry of the microencapsulated products was obtained.

Water was then added to the slurry to make a total weight of 1000 g, thereby obtaining a microcapsule slurry of 16 wt% of fenitrothion and 4 wt% of fenvalerate encapsulated with the polyurea resin (Composition 13).

The thus obtained microcapsules had an average particle diameter of 10 micrometers, wall thickness of 0.006 micrometer, and average particle diameter/wall thickness ratio of 1,667.

Example 14 4.4 g of "SUMIDUR" L8 (as indicated hereinbefore) and 100 g of phenylxylyiethane (commercial name: "HISOL" SAS-2968, made by Nippon Petroleum Chem. Co., Ltd.) were added to 100 g of fenvalerate and the mixture was agitated until a uniform solution was obtained. The solution was added to 400 g of an aqueous solution containing 10 wt% of polyvinyl alcohol (commercial name: "GOSENOL" GL-05, made by Nippon Gosei Kagaku Kogyo K. K.), and the dispersion was carried out at room temperature for several minutes by means of "T.K. autohomomixer" (Tokushu Kika Kogyo K. K.). The number of revolutions was 1,250 r.p.m. Six g of ethylene glycol was added into the dispersed solution.Thereafter the dispersed solution was gently agitated at 60"C for 24 hours and the slurry of the microencapsulated products was obtained. Water was added to the slurry to make a total weight of 1 ,000 g, thereby obtaining a slurry of fenvalerate microcapsules with polyurethane wall having an active ingredient concentration of 10 wt% (Composition 14).

The thus obtained microcapsules had an average particle diameter of 50 micrometers, wall thickness of 0. 131 micrometer, an average particle diameter/wall thickness ratio of 382.

Example 15 The procedure of Example 14 was repeated except that "T.K. autohomomixer" (as used before) was rotated at 2,300 r.p.m. in place of 1,250 r.p.m., thereby obtaining a fenvalerate microcapsule slurry with polyurethane wall having an active ingredient concentration of 10 wt% (Composition 15).

The thus obtained microcapsules had an average particle diameter of 20 micrometers, wall thickness of 0.052 micrometer, and average particle diameter/wall thickness ratio of 385.

Example 16 The procedure of Example 14 was repeated except that "T.K. autohomomixer" (as used before) was rotated at 10,000 r.pm. in place of 1,250 r.p.m., thereby obtaining a fenvalerate microcapsule slurry with polyurethane wall having an active ingredient concentration of 10 wt% (Composition 16.

The thus obtained microcapsules had an average particle diameter of 2 micrometers, wall thickness of 0.005 micrometer, and average particle diameter/wall thickness ratio of 400.

Example 17 The procedure of Example 14 was repeated except that an amount of "SUMIDUR" L(D (as indicated before) was changed to 0.9 g in place of 4.4 g and "T.K. autohomomixer" (as indicated before) was rotated at 6,500 r.pm. in place of 1,250 r.p.m., thereby obtaining a fenvalerate microcapsule slurry with polyurethane wall having an active ingredient concentration of 10 wt% (Composition 17).

The thus obtained microcapsules had an average particle diameter of 5 micrometers, wall thickness of 0.003 micrometer, and average particle diameter/wall thickness ratio of 1,667.

Example 18 The procedure of Example 14 was repeated except that an amount of "SUMIDUR" L@) (as indicated before) was changed to 0.4 g in place of 4.4 g, thereby obtaining a fenvalerate microcapsule siurry with polyurethane wall having an active ingredient concentration of 10 wt% (Composition 18).

The thus obtained microcapsules had an average particle diameter of 50 micrometers, wall thickness of 0.012 micrometer, and average particle diameter/wall thickness ratio of 4,167.

Example 19 The procedure of Example 14 was repeated except that an amount of "SUMIDUR" L8 (as indicated before) was changed to 0.1 g in place of 4.4 g and "T.K. autohomomixer" (as indicated before) was rotated at 1,500 r.p.m. in place of 1,250 r.p.m., thereby obtaining a fenvalerate microcapsule slurry with polyurethane wall having an active ingredient concentration of 10 wt% (Composition 19).

The thus obtained microcapsules had an average particle diameter of 30 micrometers, wall thickness of 0.002 micrometer, and average particle diameter/wall thickness ratio of 15,000.

Example 20 The procedure of Example 14 was repeated except that fenvalerate was replaced by fenpropathrin, and "T.K. autohomomixer" (as indicated before) was rotated at 6,500 r.p.m. in place of 1,250 r.p.m., thereby obtaining a fenpropathrin microcapsule slurry with polyurethane wall having an active ingredient concentration of 10 wt% (Composition 20).

The thus obtained microcapsules had an average particle diameter of 5 micrometers, wall thickness of 0.013 micrometer, and average particle diameter/wall thickness ratio of 385.

Example 21 1.5 g of "SUMIDUR" L) (as indicated before) was added to 200 g of fenvalerate and the mixture was heated and agitated until a uniform solution was obtained. The solution was added to 350 g of an aqueous solution containing 5 wt% of gum arabic as dispersing agent and the dispersion was carried out under heating for several minues by the use "T.K. autohomomixer" (as indicated before). The number of revolutions was 6,000 r.p.m. Thereafter, 6 g of ethylene glycol was added into the dispersed solution. Thereafter the dispersed solution was gently agitated at 70"C for 20 hours and the slurry of the microencapsulated products was obtained.

Water was added to the dispersion to make a total weight of 1,000 g, thereby obtaining a fenvalerate microcapsule slurry with polyurethane wall having an active ingredient concentration of 20 wt% (Composition 21).

The thus obtained microcapsules had an average particle diameter of 40 micrometers, wall thickness of 0.039 micrometer, and average particle diameter/wall thickness ratio of 1,026.

Example 22 The procedure of Example 21 was repeated except that an amount of "SUMIDUR" L8 (as indicated before) was changed to 1 g in place of 1.5 g, 200 g of fenvalerate was replaced by 200 g of fenpropathrin, and "T.K. autohomomixer" (as indicated before) was rotated at 6,800 r.p.m. in place of 6000 r.p.m., thereby obtaining a fenpropathrin microcapsule slurry with polyurethane wall having an active ingredient concentration of 20 wt% (Composition 22).

The thus obtained microcapsules had an average particle diameter of 30 micrometers, wall thickness of 0.02 micrometer, and average particle diameter/wall thickness ratio of 1,500.

Example 23 4 g of "SUMIDUR" L8 (as indicated before) and 150 g of "HISOL" SAS 2968 were added to 100 g of permethrin and the mixture was agitated until a uniform solution was obtained. The solution was added to 400 g of an aqueous solution containing 5 wt% of gum arabic as a dispersing agent and the dispersion was carried out at room temperature for several minutes by the use of "T.K. autohomomixer" (as indicated before). The number of revolutions was 8,600 r.p.m. Thereafter, 7 g of ethylene glycol was added into the dispersed solution. Thereafter the dispersed solution was gently agitated at 50"C for 36 hours and the slurry of the microencapsulated products was obtained.Water was added to the slurry to make a total weight of 1 ,000 g, followed by dilution to 1:2 with a aqueous solution containing 0.3 wt% of xanthan gum and 0.6 wt% of magnesium-aluminium-silicate as a thickening agent, thereby obtaining a permethrin microcapsule slurry with polyurethane wall having an active ingredient concentration of 5 wt% (Composition 23).

The thus obtained microcapsules had an average particle diameter of 15 micrometers, wall thickness of 0.029 micrometer, and average particle diameter/wall thickness ratio of 517.

Example 24 2 g of "SUMIDUR" L (as indicated before) and 50 g of xylene were added to 100 g of cypermethrin and the mixture was agitated until a uniform solution was obtained. The solution was added to 350 g of an aqueous solution containing 5 wt% of gum arabic as a dispersing agent and the dispersion was carried out under heating for several minutes by the use of "T.K.

autohomomixer" (as indicated before). The number of revolutions was 5,000 r.p.m. Thereafter, 6 g of propylene glycol was added into the dispersed solution. Thereafter the dispersed solution was gently agitated at 70"C for 24 hours and the slurry of the microencapsulated products was obtained. Water was added to the slurry to make a total weight of 1,000 g, thereby obtaining a cypermethrin microcapsule slurry with polyurethane wall having an active ingredient concentration of 10 wt% (Composition 24).

The thus obtained microcapsules had an average particle diameter of 60 micrometers, wall thickness of 0.101 micrometer, and average particle diameter/wall thickness ratio of 594.

Example 25 The procedure of Example 14 was repeated except that an amount of "SUMIDUR" L8 (as indicated before) was changed to 2 g in place of 4.4 g, 100 g of "HISOL" SAS 2968 was replaced by 100 g of xylene, fenvalerate was replaced by tetramethrin, and "T.K. autohomomixer" (as indicated before) was rotated at 2,300 r.p.m. in place of 1,250 r.p.m., thereby obtaining a tetramethrin microcapsule slurry with polyurethane wall having an active ingredient concentration of 10 wt% (Composition 25).

The thus obtained microcapsules had an average particle diameter of 20 micrometers, wall thickness of 0.022 micrometer, and average particle diameter/wall thickness ratio of 909.

Example 26 One g of "SUMIDUR" L8 (as indicated before) and 50 g of xylene were added to 100 g of allethrin and the mixture was agitated until a uniform solution was obtained. The solution was added to 260 g of an aqueous solution containing 5 wt% of gum arabic as a dispersing agent and the dispersion was carried out at room temperature for several minutes by the use of "T.K.

autohomomixer" (as indicated before). The number of revolutions was 8,000 r.p.m. Thereafter, 7 g of ethylene glycol was added into the dispersed solution. Thereafter the dispersed solution was gently agitated at 60"C for 24 hours and the slurry of the microencapsulated products was obtained.

Water was added to the slurry to make a total weight of 1,000 g, followed by dilution to 1:2 with an aqueous solution containing a 4 wt% of carboxymethyl cellulose ("CELLOGEN" 3H(3), made by Daiichi Kogyo Seiyaku K. K.), thereby obtaining an allethrin microcapsule slurry with polyurethane wall having an active ingredient concentration of 5 wt% (Composition 26).

The thus obtained microcapsules had an average particle diameter of 20 micrometers, wall thickness of 0.015 micrometer, and average particle diameter/wall thickness ratio of 1,333.

Example 27 The procedure of Example 21 was repeated except that "SUMIDUR" L@) (as used before) was replaced by a mixture of 0.8 g of "SUMIDUR" L8 and 0.1 g of toluene diisocyanate ("SUMI DUR" T808, made by Sumitomo-Bayer Urethane Co., Ltd.), and 200 g of fenvalerate was replaced by 200 g of phenothrin, thereby obtaining a phenothrin microcapsule slurry with polyurethane wall having an active ingredient concentration of 20 wt% (Composition 27).

The thus obtained microcapsules had an average particle diameter of 20 micrometers, wall thickness of 0.011 micrometer, and average particle diameter/wall thickness ratio of 1,818.

Example 28 Zero point nine g of "SUMIDUR" L8 (as indicated before) and 160 g of fenitrothion [0,0 dimethyl-0-(3-methyl-4-nitrophenyl)phosphorothioate] were added to 40 g of fenvalerate and the mixture was agitated until a uniform solution was obtained. The solution was added to 400 g of an aqueous solution containing 10 wt% of "GOSENOL" GL-058 (as indicated before) and the dispersion was carried out at room temperature for several minutes by the use of "T.K.

autohomomixer" (as indicated before). The number of revolutions was 6,500 r.p.m. Thereafter, 10 g of ethylene glycol was added into the dispersed solution. Thereafter the dispersed solution was gently agitated at 60"C for 24 hours and the slurry of the microencapsulated products was obtained. Water was added to the slurry to make a total weight of 1,000 g, thereby obtaining a microcapsule slurry with polyurethane wall having 16 wt% of fenitrothion and 4 wt% of fenvalerate (Composition 28).

The thus obtained microcapsules had an average particle diameter of 5 micrometers, wall thickness of 0.003 micrometer, and average particle diameter/wall thickness ratio of 1,667.

Example 29 Two hundred g of fenvalerate, 50 g of xylene and 4 g of trimesoyl chloride were mixed until the solution was uniform. The solution was added to 500 g of an aqueous 2 % gum arabic. The dispersion was carried out at room temperature for several minutes by the use of "T.K.

autohomomixer" (Tokushu Kika Kogyo K. K.). The dispersed solution was gently agitated with a magnetic stirrer, into which 100 g of an aqueous solution containing 3 g of diethylenetriamine and 6 g of sodium carbonate, followed by allowing it to stand for 2 hours while continuing the gentle agitation. Thereafter, the suspension was neutralized with an 1N hydrochloric acid solution. Water was added thereto so as to make a total weight of 1,000 g, thereby obtaining a fenvalerate microcapsule slurry with polyurethane wall having an active ingredient concentration of 20 wt96 (Composition 29).

The thus obtained microcapsules had an average particle diameter of 22 micrometers, wall thickness of 0.049 micrometer, and average particle diameter/wall thickness ratio of 449.

Comparative Example 1 The procedure of Example 1 was repeated except that an amount of "SUMIDUR" LE (as indicated before) was changed to 15 g in placed of 4 g and "T.K. autohomomixer" (as indicated before) was rotated at 6,500 r.p.m. in place of 1,250 r.p.m., thereby obtaining a fenvalerate microcapsule slurry with polyurea wall having an active ingredient concentration of 10 wt% (Composition Composition 1).

The thus obtained microcapsules had an average particle diameter of 5 micrometers, a wall thickness of 0.04 micrometer, and average particle diameter/wall thickness ratio of 125.

Comparative Example 2 The procedure of Example 5 was repeated except that an amount of "SUMIDUR" LB (as indicated before) was changed to 15 g from 4 g and "T.K. autohomomixer" (as indicated before) was rotated at 2,150 r.p.m. in place of 1,500 r.p.m., thereby obtaining a fenpropathrin microcapsule slurry with polyurea wall having an active ingredient concentration of 10 wt% (Comparative Composition 2).

The thus obtained microcapsules had an average particle diameter of 25 micrometers, wall thickness of 0.333 micrometer, and average particle diameter of 25 micrometers, wall thickness of 0.333 micrometer, and average particle diameter/wall thickness ratio of 75.

Comparative Example 3 A fenvalerate emulsifiable concentrate having an active ingredient concentration of 10 wt% was prepared by a usual manner using the following recipe (Comparative Composition 3).

Fenvalerate 10 parts by weight "SORPOL" 3005x() 8 10 parts by weight (registered trade name of Toho Kagaku K. K.: mixture of a nonionic surface active agent and an anionic surface active agent) Xylene balance 100 parts by weight Comparative Example 4 A fenpropathrin emulsifiable concentrate having an active ingredient concentration of 10 wt% was prepared by a usual manner using the following recipe (Comparative Composition 4).

Fenprospathrin 10 parts by weight "SORPOL" 3005 x 8 10 parts by weight (as used above) Xylene balance 100 part by weight Comparative Example 5 The procedure of Example 14 was repeated except that an amount of "SUMIDUR" L8 (as used before) was changed to 17.6 g from 4.4 g and "T.K. autohomomixer" (as used before) was rotated at 6,500 r.p.m. in place of 1,250 r.p.m., thereby obtaining a fenvalerate microcapsule slurry with polyurethane wall having an active ingredient concentration of 10 wt% (Comparative Composition 5).

The thus obtained microcapsules had an average particle diameter of 5 micrometers, wall thickness of 0.052 micrometer, and average particle diameter/wall thickness ratio of 96.

Comparative Example 6 The procedure of Example 20 was repeated except that an amount of "SUMIDUR" L8 (as used before) was changed to 25 g from 4.4 g and "T.K. autohomomixer" (as used before) was rotated at 2,300 r.p.m. in place of 6,500 r.p.m., thereby obtaining a fenpropathrin microcapsule slurry with polyurethane wall having an active ingredient concentration of 10 wt% (Comparative Composition 6).

The thus obtained microcapsules had an average particle diameter of 20 micrometers, wall thickness of 0.291 micrometer, and average particle diameter/wall thickness ratio of 69.

Test Example 1 A 1:1000 dilution with water of each test composition, indicated in Table 1, was sprayed by means of a spray gun over potted cabbages (ever harvesting cabbages) mounted on a turn table in an amount 50 ml per five pots. Each dilution contained 0.0002 wt% of special Rino (made by Nippon Noyaku K. K.) as a spreader.

The thus treated cabbage pots were allowed to stand in a glass greenhouse and leaves of the cabbages were cut away after a predetermined period of time, followed by a placing in a cup having a diameter of 12 cm together with 10 tobacco cut worm larvae of 3 years old. After 48 hours, the number of the dead insects was checked. The test was repeated three times and a mortality was calculated according to the following equation.

(total number of the dead of three tests) Mortality(%)= x 100 (total number of tested insects in three tests) The results are shown in Tables 1 and 2.

Table 1 Residual Efficacy on Tobacco Cutworms (Mortality %) <img class="EMIRef" id="027056312-00130001" />

Mortality <SEP> (%) <SEP> at <SEP> the <tb> Average <SEP> Wall <SEP> Average <SEP> particle <tb> Test <SEP> indicated <SEP> days <SEP> after <tb> diameter <tb> particle <SEP> treatment <tb> thickness <tb> compositions <SEP> diameter <tb> Wall <SEP> Thickness <tb> 0 <SEP> 7 <SEP> days <SEP> 14 <SEP> days <tb> ( m) <SEP> ( m) <tb> <SEP> Present <tb> composition <tb> 1 <SEP> 50 <SEP> 0.109 <SEP> 459 <SEP> 100 <SEP> 83.3 <SEP> 70.0 <tb> 2 <SEP> 5 <SEP> 0.011 <SEP> 455 <SEP> 83.3 <SEP> 66.7 <SEP> 53.3 <tb> 3 <SEP> 5 <SEP> 0.002 <SEP> 2500 <SEP> 100 <SEP> 83.3 <SEP> 50.0 <tb> 4 <SEP> 20 <SEP> 0.002 <SEP> 10000 <SEP> 100 <SEP> 90.0 <SEP> 73.3 <tb> Comparative <tb> composition <tb> 1 <SEP> 5 <SEP> 0.04 <SEP> 125 <SEP> 63.3 <SEP> 50.0 <SEP> 36.7 <tb> 3 <SEP> - <SEP> - <SEP> - <SEP> 90.0 <SEP> 63.3 <SEP> 40.0 <tb> Table 2 Residual Efficacy on Tobacco Cutworms (Mortality %) <img class="EMIRef" id="027056312-00140001" />

Average <SEP> Mortality <SEP> (%) <SEP> at <SEP> the <tb> Average <SEP> particle <tb> Test <SEP> Wall <SEP> indicated <SEP> days <SEP> after <tb> particle <tb> diameter <SEP> treatment <tb> compositions <SEP> diameter <SEP> thickness <tb> 7 <SEP> 14 <SEP> 28 <tb> ( m) <SEP> ( m) <SEP> Wall <SEP> thickness <SEP> 0 <tb> days <SEP> days <SEP> days <tb> <SEP> Present <tb> composition <tb> 15 <SEP> 20 <SEP> 0.052 <SEP> 385 <SEP> 86.7 <SEP> 73.3 <SEP> 70.0 <SEP> 66.7 <tb> 17 <SEP> 5 <SEP> 0.003 <SEP> 1667 <SEP> 100 <SEP> 83.3 <SEP> 70.0 <SEP> 43.3 <tb> 18 <SEP> 50 <SEP> 0.012 <SEP> 4167 <SEP> 100 <SEP> 90.0 <SEP> 76.7 <SEP> 63.3 <tb> 19 <SEP> 30 <SEP> 0.002 <SEP> 15000 <SEP> 100 <SEP> 86.7 <SEP> 73.3 <SEP> 66.7 <tb> Comparative <tb> composition <tb> 5 <SEP> 5 <SEP> 0.052 <SEP> 96 <SEP> 60 <SEP> 43.3 <SEP> 20.0 <SEP> 13.3 <tb> 3 <SEP> - <SEP> - <SEP> - <SEP> 96.7 <SEP> 70.0 <SEP> 53.3 <SEP> 26.7 <tb> Test Example 2 Potted kidneys 2 weeks after seeding (two kidneys per pot) was inoculated with about 30 female carmine mites per pot. Three days after the inoculation, a 1:1000 dilution of each test composition in Table 3 was sprayed over the pots on a turn table by means of a spray gun in an amount of 50 ml per 5 pots. Each dilution contained 0.0002 wt% of special Rino(B) (as indicated above) as a spreader.

The treated pots were allowed to stand in a net-shaded chamber and the number of the female mites was checked after a predetermined period of time.

Table 3 Residual Efficacy on Carmine Mites (Total number of female mites in 5 pots) <img class="EMIRef" id="027056312-00160001" />

Average <SEP> Average <SEP> particle <SEP> Residual <SEP> effect <SEP> (total <tb> Wall <tb> Test <SEP> diameter <SEP> number) <SEP> at <SEP> the <SEP> indicated <tb> particle <tb> days <SEP> after <SEP> treatment <tb> thickness <tb> compositions <SEP> diameter <tb> Wall <SEP> thickness <tb> ( m) <SEP> ( m) <SEP> 1 <SEP> 7 <SEP> 21 <tb> 0 <tb> day <SEP> days <SEP> days <tb> <SEP> Present <tb> composition <tb> 5 <SEP> 5 <SEP> 0.011 <SEP> 455 <SEP> 162 <SEP> 36 <SEP> 17 <SEP> 45 <tb> Comparative <tb> composition <tb> 2 <SEP> 25 <SEP> 0.333 <SEP> 75 <SEP> 161 <SEP> 87 <SEP> 98 <SEP> 140 <tb> 4 <SEP> - <SEP> - <SEP> - <SEP> 163 <SEP> 44 <SEP> 29 <SEP> 121 <tb> Nontreatment <SEP> - <SEP> - <SEP> - <SEP> 162 <SEP> 220 <SEP> 233 <SEP> 654 <tb> Test Example 3 The same procedure as in Test Example 2 was repeated using test compositions indicated in Table 4. The test results are shown in Table 4. Table 4 Residual Efficacy on Carmine Mites (Total number of female mites in 5 pots) <img class="EMIRef" id="027056312-00180001" />

Residual <SEP> effect <SEP> (total <tb> Average <tb> Average <SEP> particle <tb> Test <SEP> number) <SEP> at <SEP> the <SEP> indicated <tb> Wall <tb> particle <SEP> diameter <tb> days <SEP> after <SEP> treatment <tb> compositions <SEP> diameter <SEP> thickness <tb> Wall <SEP> thickness <SEP> 1 <SEP> 7 <SEP> 21 <tb> ( m) <SEP> ( m) <SEP> 0 <tb> day <SEP> days <SEP> days <tb> <SEP> Present <tb> composition <tb> 20 <SEP> 5 <SEP> 0.013 <SEP> 385 <SEP> 162 <SEP> 37 <SEP> 11 <SEP> 42 <tb> Comparative <tb> composition <tb> 6 <SEP> 20 <SEP> 0.291 <SEP> 69 <SEP> 161 <SEP> 80 <SEP> 87 <SEP> 135 <tb> 4 <SEP> - <SEP> - <SEP> - <SEP> 163 <SEP> 43 <SEP> 20 <SEP> 119 <tb> Nontreatment <SEP> - <SEP> - <SEP> - <SEP> 161 <SEP> 226 <SEP> 232 <SEP> 752 <tb> Test example 4 Fenvalerate microcapsule slurries of the invention (Present Compositions 1 and 4) and a fenvalerate emulsifiable concentrate (Comparative Composition 3) were each diluted to a predetermined concentration and placed in a 21 cmx 16 cmx23 cm glass container in an amount of 5 liters. Ten red killifishes were placed in the container in order to check the life or death after 48 hours. Based on the results, a concentration for a medium lethal dose was determined as TLm48(MC).

The above procedure was repeated using fenvalerate stock to determine a median lethal dose for fenvalerate as TLm48(TG).

A value of TLm48(MC)/TLm48(TG) was calculated and taken as a fish toxicity reduction rate.

The results are shown in Table 5.

Test compositions Fish Toxicity Reduction Rate Present composition 1 600 Present composition 4 20 Comparative composition 3 1

Claims (14)

1. A microencapsulated pyrethroid insecticidal and/or acaricidal composition which comprises at least one pyrethroid compound encapsulated in a wall formed of a synthetic polymer and having an average particle diameter of not more than 80 micrometers, wall thickness of not more than 0.3 micrometer, and average particle diameter/wall thickness ratio of not less than 250.
2. An insecticidal and/or acaricidal composition as claimed in Claim 1 in which the said synthetic polymer for the microcapsules is a member selected from the group consisting of polyurethane resins, polyurea resins, polyamide resins, polyamide-polyurea resins, polycarbonate resins, polysulfonate resins, polysulfonamide resins and epoxy resins.
3. An insecticidal and/or acaricidal composition as claimed on Claim 2 in which the said synthetic polymer is a polyurea resin.
4. An insecticidal and/or acaricidal composition as claimed in Claim 2 in which the said synthetic polymer is a polyurethane resin.
5. An insecticidal and/or acaricidal composition as claimed in any one of Claims 1 to 4 in which the pyrethroid compound is a member selected from the group consisting of fenvalerate, fenpropathrin, permethrin, cypermethrin, tetramethrin, allethrin, phenothrin, deltamethrin, cyhalthrin, their isomers, and mixtures thereof.
6. A composition as claimed in Claim 1 and substantially as specifically described herein with reference to any one of Examples 1 to 29.
7. A process for preparing a microencapsulated pyrethroid insecticidal and/or acaricidal composition containing at least one pyrethroid compound encapsulated in a wall formed of synthetic polymer and having an average particle diameter of not more than 80 micrometers, a wall thickness of not more than 0.3 micrometer and average particle diameter/wall thickness ratio of not less than 250, which comprises adding an oii-soluble reactant A to an oil phase containing pyrethroid insecticide and/or acaricide, dispersing the mixture in water, adding, if necessary, a reactant B to the dispersed solution, the said reactant B being able to react with the reactant A to form a polymer and allowing interfacial polymerization to proceed between the reactant A and the reactant B or between the reactant A and water when no reactant B is added; or adding the reactant A to an oil phase containing pyrethroid insecticide and/or acaricide, dispersing the oil phase in an aqueous phase containing the reactant B, and allowing polymerization between the reactant A and the reactant B to proceed.
8. A process as claimed in Claim 7 in which the material of the wall is selected from the group consisting of polyurethane resins, polyurea resins, polyamide resins, polyamide-polyurea copolymers, polyester resins, polycarbonate resins, polysulfonate resins, polysulfonamide resins and epoxy resins.
9. A process as claimed in Claim 7 in which the reactant A is selected from the group consisting of polyfunctional isocyanates having a least two isocyanate groups, polyfunctional acid chlorides having at least two COCI groups, phosgene, polyfunctional sulfonylchlorides having at least two SO2Cl groups and polyfunctional epoxy compounds having at least two epoxy rings.
10. A process as claimed in any one of Claims 7 to 9 in which the reactant B is selected from the group consisting of polyhydric alcohols having at least two hydroxyl groups and polyfunctional amines having at least two amino groups.
11. A process as claimed in any one of Claims 7 to 10 in which the insecticide and/or acaricide is selected from fenvalerate, fenpropathrin, permethrin, cypermethrin, tetramethrin, allethrin, phenothrin, deltamethrin, cyhalothrin, their isomers, and mixtures thereof.
12. A process as claimed in Claim 7 substantially as specificially described herein with reference to Examples 1 to 29.
13. A composition as claimed in any one of Claims 1 to 5 whenever made by a process as claimed in any one of Claims 7 to 12.
14. A method for controlling insects and/or mites by use of a microencapsulated composition as claimed in any one of Claims 1 to 6 or Claim 13.
GB8706188A 1986-03-17 1987-03-16 Microencapsulated pyrethroid insecticidal and/or acaricidal composition for agricultural uses Expired - Lifetime GB2187957B (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP5903486A JPH0676287B2 (en) 1986-03-17 1986-03-17 Agricultural insecticide, miticide composition
JP5903386A JPH0676286B2 (en) 1986-03-17 1986-03-17 Agricultural insecticide, miticide composition
JP16450486A JPH0764686B2 (en) 1986-07-11 1986-07-11 Pyrethroid insecticide, acaricide composition

Publications (3)

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GB8706188D0 GB8706188D0 (en) 1987-04-23
GB2187957A true true GB2187957A (en) 1987-09-23
GB2187957B GB2187957B (en) 1990-03-21

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DE (1) DE3708671C2 (en)
DK (1) DK170850B1 (en)
ES (1) ES2004903A6 (en)
FR (1) FR2595545B1 (en)
GB (1) GB2187957B (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2625074A1 (en) * 1987-12-25 1989-06-30 Sumitomo Chemical Co Composition microencapsulated destiny to struggle against cockroaches
EP0543027A1 (en) * 1991-06-12 1993-05-26 MITSUI TOATSU CHEMICALS, Inc. Insecticidal composition and production thereof
WO1997006688A1 (en) * 1995-08-16 1997-02-27 Bayer Aktiengesellschaft Composition having an insecticidal effect
WO1997014308A1 (en) * 1995-10-20 1997-04-24 Chinoin Gyógyszer és Vegyészeti Termékek Gyára Rt. Microencapsulated insecticide preparations and a process for the preparation thereof
US5733561A (en) * 1991-06-12 1998-03-31 Mitsui Toatsu Chemicals, Incorporated Insecticide composition and production process thereof
WO1998049901A1 (en) * 1997-05-08 1998-11-12 Ben Gurion University Of The Negev Research And Development Authority A process for encapsulating laygon
WO2001096009A2 (en) * 2000-06-12 2001-12-20 Kureha Kagaku Kogyo Kabushiki Kaisha Microcapsule suspension and process for production thereof
WO2003051116A1 (en) * 2001-12-14 2003-06-26 Mars, Incorporated Microencapsulated insecticide
US8263099B2 (en) 2004-03-01 2012-09-11 Sumitomo Chemical Company, Limited Insect growth regulating composition
EP2589290A1 (en) 2011-11-04 2013-05-08 Endura S.p.a. Microcapsules comprising a pyrethroid and/or neonicontinoid and a synergizing agent
WO2013133731A1 (en) * 2012-03-08 2013-09-12 Sapec Agro S.A. Insecticide formulation, method for manufacturing the same and use thereof
US20160192644A1 (en) * 2013-06-26 2016-07-07 Sumitomo Chemical Company, Limited Microcapsules for thermal transpiration

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DE10037656B4 (en) * 2000-07-31 2006-12-14 Henkel Kgaa A process for producing capsules by miniemulsion polymerization aktivstoffhaltiger
CA2605581C (en) 2005-04-22 2014-08-05 Endura S.P.A. Biologically active formulation based on cyclodextrin supramolecular complexes
JP5318564B2 (en) * 2005-04-22 2013-10-16 エンデュラ ソシエタ ペル アチオニ Innovative Formulations

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GB2113170A (en) * 1982-01-18 1983-08-03 Kureha Chemical Ind Co Ltd Microencapsulated agricultural pesticides

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US4497793A (en) * 1980-08-11 1985-02-05 Pennwalt Corporation Microencapsulated naturally occuring pyrethrins
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Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2625074A1 (en) * 1987-12-25 1989-06-30 Sumitomo Chemical Co Composition microencapsulated destiny to struggle against cockroaches
EP0322820A1 (en) * 1987-12-25 1989-07-05 Sumitomo Chemical Company, Limited Use of a microencapsulated compositon for the control of cockroaches
GB2214080A (en) * 1987-12-25 1989-08-31 Sumitomo Chemical Co Microencapsulated cockroach-controlling composition
US5063059A (en) * 1987-12-25 1991-11-05 Sumitomo Chemical Co., Ltd. Microencapsulated cockroach-controlling composition
GB2214080B (en) * 1987-12-25 1992-01-15 Sumitomo Chemical Co 'method of controlling cockroaches using a composition'
US5306499A (en) * 1987-12-25 1994-04-26 Sumitomo Chemical Company, Limited Microencapsulated cockroach-controlling composition
EP0543027A1 (en) * 1991-06-12 1993-05-26 MITSUI TOATSU CHEMICALS, Inc. Insecticidal composition and production thereof
EP0543027A4 (en) * 1991-06-12 1994-07-13 Mitsui Toatsu Chemicals Insecticidal composition and production thereof
US5733561A (en) * 1991-06-12 1998-03-31 Mitsui Toatsu Chemicals, Incorporated Insecticide composition and production process thereof
WO1997006688A1 (en) * 1995-08-16 1997-02-27 Bayer Aktiengesellschaft Composition having an insecticidal effect
WO1997014308A1 (en) * 1995-10-20 1997-04-24 Chinoin Gyógyszer és Vegyészeti Termékek Gyára Rt. Microencapsulated insecticide preparations and a process for the preparation thereof
WO1998049901A1 (en) * 1997-05-08 1998-11-12 Ben Gurion University Of The Negev Research And Development Authority A process for encapsulating laygon
WO2001096009A2 (en) * 2000-06-12 2001-12-20 Kureha Kagaku Kogyo Kabushiki Kaisha Microcapsule suspension and process for production thereof
WO2001096009A3 (en) * 2000-06-12 2002-06-20 Kureha Chemical Ind Co Ltd Microcapsule suspension and process for production thereof
EP1623756A1 (en) * 2000-06-12 2006-02-08 Kureha Corporation Microcapsule suspension liquid and process for production thereof
US7718572B2 (en) 2000-06-12 2010-05-18 Kureha Corporation Microcapsule suspension liquid and process for production thereof
WO2003051116A1 (en) * 2001-12-14 2003-06-26 Mars, Incorporated Microencapsulated insecticide
US8263099B2 (en) 2004-03-01 2012-09-11 Sumitomo Chemical Company, Limited Insect growth regulating composition
EP2589290A1 (en) 2011-11-04 2013-05-08 Endura S.p.a. Microcapsules comprising a pyrethroid and/or neonicontinoid and a synergizing agent
US9044012B2 (en) 2011-11-04 2015-06-02 Endura S.P.A. Use of formulations having insecticidal activity
WO2013133731A1 (en) * 2012-03-08 2013-09-12 Sapec Agro S.A. Insecticide formulation, method for manufacturing the same and use thereof
US20160192644A1 (en) * 2013-06-26 2016-07-07 Sumitomo Chemical Company, Limited Microcapsules for thermal transpiration

Also Published As

Publication number Publication date Type
ES2004903A6 (en) 1989-02-16 application
FR2595545A1 (en) 1987-09-18 application
DK170850B1 (en) 1996-02-12 grant
FR2595545B1 (en) 1993-04-30 grant
DE3708671C2 (en) 1998-06-04 grant
DK134187D0 (en) 1987-03-16 grant
DE3708671A1 (en) 1987-09-24 application
DK134187A (en) 1987-09-18 application
GB2187957B (en) 1990-03-21 grant
GB8706188D0 (en) 1987-04-23 grant

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