JPH05178703A - Insecticidal composition and its production - Google Patents

Abstract

PURPOSE:To produce the subject composition exhibiting a stable effect for a long period and safe to aquatic animals by coating a pyrethroid-based insecticide with a wall membrane composed of melamine-formaldehyde or its derivative in the presence of an anionic polymer surfactant. CONSTITUTION:One or more kinds of compounds selected from melamine- formaldehyde, methylol melamine monomer or its low-molecular polymer and an alkylated methylol melamine monomer or its low-molecular polymer are dissolved in an anionic polymer surfactantcontaining water. To the resultant solution, a hydrophobic solution prepared by dissolving or compatibilizing a liquid pyrethroid-based insecticide or a pyrethroid-based insecticide in a high- boiling solvent (e.g. an alkyl phthalate) is then added so as to be emulsified or dispersed. The resultant emulsion or dispersion is subsequently heated to form a wall membrane composed of polycondensate of the melamine monomer or the low-molecular polymer on the surface of the emulsified particles. Thereby, the objective aqueous suspension type microcapsular insecticide composition is obtained. The weight ratio of the core material to the wall membrane is preferably about (500:1) to (20:1).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a microcapsule insecticide composition in which melamine-formaldehyde or a derivative thereof is used as a wall film and a pyrethroid insecticide is coated in the presence of an anionic polymer surfactant, and a method for producing the same. It is about.

[0002]

BACKGROUND OF THE INVENTION Pyrethroid insecticides are generally emulsions or oils prepared by dissolving them in an organic solvent containing a surfactant, and fine powders of mineral matter as solid preparations, wettable powders or powders prepared by adsorbing them to diatomaceous earth. Alternatively, it is formulated in the form of granules. However, these existing formulation types have various problems such as environmental pollution of the emulsion by the organic solvent or dust of the wettable powder.
Further, when seeking a long-term residual effect with these formulation types, a higher concentration application than the application amount is usually required, which may cause a problem in terms of environmental impact or safety. There is a strong demand for a formulation type with a high residual effect.

Many pyrethroid insecticides are highly toxic to fish, and therefore their use in paddy fields has been limited. Therefore, there is a strong demand for a dosage form having higher safety for aquatic animals when the pyrethroid insecticide is used in paddy fields.

Under these circumstances, research and development of microencapsulated preparations, which are highly expected as substitutes for emulsions and wettable powders, and which are also excellent in safety, have been actively conducted. ..

However, conventional microcapsules containing an insecticidal active ingredient are mainly those utilizing interfacial polymerization reaction, and these are incomplete in terms of preparation method or stable insecticidal effect.

The microcapsules of the complex coacervation method are incomplete in terms of cost and storage stability of raw materials used, and a formulation type which overcomes these problems and is excellent in stability of insecticidal activity has been proposed. It has been demanded.

Microcapsules containing melamine-formaldehyde as a wall film have been mainly developed for pressure-sensitive recording paper applications (Japanese Patent Laid-Open No. 61-11138). This technology mainly describes microcapsules containing a dye, and in order to prevent the microcapsule inclusions from developing color under no pressure, the weight ratio of the core substance to the microcapsule wall film is 2: 1 to. The range is 20: 1 and the microcapsule particles are adjusted to 5 μm or less.

The microcapsules containing a pyrethroid insecticide include microcapsules containing a polyurethane polymer (Japanese Patent Publication No. 55-38325), polyamide, polyamide-polyurea, polyurethane, polyurea, etc. Microcapsules of pyrethroid insecticides obtained by polymerization reaction (JP-A-61-115006) and microcapsules of pyrethroid insecticides obtained by a complex coacervation method using gelatin-gum arabic (JP-A-64-115). −66104
), A microcapsule agent coated with a polyurethane-based polymer (JP-A-2-196703), and the like.

The method of microencapsulation utilizing the interfacial polymerization method (Japanese Patent Laid-Open No. 61-115006) requires that one of the monomers that undergo a polymerization reaction be dissolved in the core substance, and the monomer is incompatible with the drug substance. Is extremely difficult to encapsulate and does not exert a sufficient insecticidal effect.

Further, a microencapsulation method by a complex coacervation method using a natural polysaccharide (Japanese Patent Laid-Open No. 64-66)
104) can be reacted under relatively mild conditions, but natural polysaccharides have supply-related concerns, and therefore cost can vary significantly, and also tend to decay and agglomerate. Therefore, it has a problem that it cannot withstand long-term storage because of the fact that it has a pesticidal effect, and that the insecticidal effect is insufficient.

Further, even when the melamine-formaldehyde system is used as the wall film, there is a problem that the insecticidal effect is insufficient if the weight ratio of the core substance to the microcapsule wall film or the size of the microcapsule particles is in a certain range. ..

[0012]

An object of the present invention is to provide a water-suspension type microencapsulated composition of a pyrethroid insecticide which exhibits a stable insecticidal effect for a long period of time and has reduced toxicity to aquatic animals. Is.

[0013]

The object of the present invention is to use a liquid pyrethroid insecticide or a hydrophobic solution obtained by dissolving or compatibilizing a pyrethroid insecticide in a high boiling point solvent as a core substance, and use melamine-formaldehyde and methylolmelamine as a single substance. Water suspension having a thin film obtained by polycondensation of one or more selected from the group consisting of a monomer or a low molecular weight polymer thereof, an alkylated methylolmelamine monomer or a low molecular weight polymer thereof and a combination thereof. Type microcapsule insecticidal composition.

This composition, in particular the one in which the weight ratio of the core substance to the microcapsule wall film or the size of the microcapsule particles is in an appropriate range, was stable over an extremely long period as compared with existing dosage forms. An insecticidal effect can be expressed.

Further, this composition has significantly less toxicity to aquatic animals than conventional pyrethroid emulsions or other commercially available insecticidal emulsions.

The water-suspended microcapsule insecticide composition of the present invention comprises a melamine-formaldehyde, a methylol melamine monomer or a low molecular weight polymer thereof, an alkylated methylol melamine monomer or a low molecular weight polymer thereof, and these At least one selected from the group consisting of combinations is dissolved in water containing an anionic polymer surfactant, and a liquid pyrethroid insecticide or a pyrethroid insecticide is dissolved or phased in a high boiling solvent in the solution. It is manufactured by adding a dissolved hydrophobic solution, emulsifying and dispersing, and heating to polycondensate the melamine monomer and / or low molecular weight polymer around the emulsified particles to form a wall film.

Examples of the pyrethroid insecticide used in the present invention are shown below, but the invention is not limited thereto.

For example, 3-phenoxybenzyl (1R
S) -cis, trans-3- (2,2-dichlorovinyl) -2,2-dimethylcyclopropanecarboxylate [permethrin], α-cyano-3-phenoxybenzyl-1- (4-ethoxyphenyl) -2 , 2-Dichlorocyclopropanecarboxylate [cycloprotoline], (RS) -α-cyano-3-phenoxybenzyl (RS) -2- (4-chlorophenyl) -3-isovalerate [fenvalerate], (S)- α-cyano-
3-phenoxybenzyl (S) -2- (4-chlorophenyl) isovalerate [esfenvalerate], α
-Cyano-3-phenoxybenzyl (S) -2- (4-
Difluoromethoxyphenyl) isovalerate [flucitrinate], α-cyano-3-phenoxybenzyl
2- (2-chloro-4-trifluoromethylaniline)
Isovalerate [fluvalinate], (RS) -α-cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcyclopropanecarboxylate [phenpropasline], 3-phenoxybenzyl (1R) -cis, trans- Chrysanthemate [d-phenothrin], (RS) -α-cyano-3-phenoxybenzyl (1R) -cis, trans-chrysanthemate [cyphenothrin], (RS) 3-allyl-2-methyl-4-
Oxocyclopent-2-enyl (1RS) -cis, trans-chrysanthemate [allethrin], α-
Cyano-3-phenoxybenzyl (1R) -cis, trans-3-phenoxybenzyl (1R) -cis, trans-3- (2,2-dichlorovinyl) -2,2-dimethylcyclopropanecarboxylate [cypermethrin] , (S) -α-Cyano-3-phenoxybenzyl (1R) -cis-3- (2,2-dibromovinyl)-
2,2-Dimethylcyclopropanecarboxylate [deltamethrin], (S) -α-3-phenoxybenzyl (1R) -cis-2,2-dimethyl-3- (1,2,2)
2,2-Tetrabromoethyl) cyclopropanecarboxylate [tralomethrin], 3,4,5,6-tetrahydroimidomethyl (1RS) -cis, trans-chrysanthemate [tetramethrin], 5-benzyl-3-
Furylmethyl (1RS) -cis, trans-chrysanthemate [resmethrin], α-cyano-4-fluoro-
3-phenoxybenzyl (1R, trans) -2,2
-Dimethyl-3- (2,2-dichlorovinyl) cyclopropanecarboxylate [Cyfluthrin] and the like are used.

In particular, the general formula (1)

[0020]

[Chemical 3] (In the formula, X represents an oxygen atom or a methylene group, R represents a lower alkyl group or a halomethyl group, and R ₁ represents a hydrogen atom or a fluorine atom.) And their isomers are preferable. Examples of the compound represented by the general formula (1) are as follows, and the compound numbers are referred to in the following description.

Compound 1: 2- (4-ethoxyphenyl)
2-Methylpropyl 3-phenoxybenzyl ether compound 2: 2- (4-difluorobromomethoxyphenyl) -2-methylpropyl 3-phenoxybenzyl ether compound 3: 2- (4-ethoxyphenyl) -2-methyl-5 -(4-Fluoro-3-phenoxyphenyl) pentane compound 4: 2- (4-difluorochloromethoxyphenyl) -2-methylpropyl 3-phenoxybenzyl ether compound 5: 2- (4-trifluoromethoxyphenyl)
2-Methylpropyl 3-phenoxybenzyl ether.

Of course, it is also possible to use a mixture of these different insecticidal active ingredients as well as other mixed ingredients such as insecticides and acaricides.

In addition to these insecticidal active ingredients, it is desirable to incorporate a high boiling point solvent in the core substance as a cosolvent. As the high boiling point solvent, alkylbenzenes, phenylxylylethane, methylnaphthalene, or alkyl esters such as phthalic acid, trimellitic acid, sebacic acid, and adipic acid can be used. Particularly, in consideration of stability of effects, influence on the environment and the like, alkyl groups having 8 to 13 carbon atoms of phthalic acid alkyl esters are particularly preferable, and the alkyl group is either linear or branched. The blending ratio of the cosolvent depends on the concentration of the active ingredient in the target microcapsule slurry, but it is desirable that the cosolvent is contained in the hydrophobic solution as the core substance in an amount of 10 to 90%. Examples of the phthalic acid alkyl ester having an alkyl group having 8 to 13 carbon atoms relating to the present invention include dinormal octyl phthalate, dinormalnonyl phthalate, diisononyl phthalate, dinormal decyl phthalate, diisodecyl phthalate, dinormal undecyl phthalate, and dinormal decyl phthalate. Examples thereof include normal dodecyl phthalate and dinormal tridecyl phthalate. These phthalic acid alkyl esters may be used alone or as a mixture of several kinds. Further, if necessary, a synergist such as piperonyl butoxide can be added to the core substance.

As the anionic polymer surfactant used for emulsifying and dispersing the core substance which is a hydrophobic solution, ethylene / maleic anhydride copolymer, styrene /
Maleic acid copolymers, vinyl acetate / maleic anhydride copolymers and the like can be used, and preferably, JP-A-61-61
At least 1 from each of the monomers (A) acrylic acid, methacrylic acid, (B) acrylonitrile or methacrylonitrile, and (C) acrylamidoalkylsulfonic acid or a sulfoalkyl ester of acrylic acid described in -4524;
Anionic polymeric surfactants obtained by polymerizing certain monomers are preferred. More preferably (A) acrylic acid 20-70
Mol%, (B) acrylonitrile 20-70 mol%, (C) 2-
Acrylamido-2-methylpropanesulfonic acid 0.5-
It is a copolymer having a monomer constitution of 20 mol% or a salt thereof, and its 20 wt% aqueous solution has a pH of 4.0 at 25 ° C.
A viscosity of 10 to 1000 cps is preferable.

The starting material for the melamine-formaldehyde polycondensate that forms the microcapsule wall film in the present invention is:
One or more water-soluble capsule walls selected from the group consisting of melamine-formaldehyde, methylol melamine monomer or low molecular weight polymer thereof, alkylated methylol melamine monomer or low molecular weight polymer thereof, and combinations thereof. Precursors are used.

Microencapsulation is carried out by dissolving melamine-formaldehyde, which is a precursor of the capsule wall, or a derivative thereof in an aqueous solution containing an anionic polymer surfactant, and the insecticidal active ingredient to be the core substance in the solution. A hydrophobic solution containing is emulsified and dispersed using an emulsifying and dispersing device, and then heated to cause a polymerization reaction.

As a preferable method, the above-mentioned Japanese Patent Laid-Open No. 61-
A water-soluble capsule wall precursor, that is, a melamine-formaldehyde derivative, is dissolved in a solution in which the pH of an aqueous solution containing a certain amount of anionic polymer surfactant shown in 4524 is adjusted to about 4 with 5N NaOH, and then T. K. A hydrophobic solution containing an insecticidal active ingredient serving as a core substance is emulsified and dispersed by an emulsifying and dispersing device such as an automixer (trade name of Tokushu Kika Kogyo Co., Ltd.). After that, heat to about 60 ℃,
This is a method of obtaining a target microcapsule slurry by reacting for about 2 to 3 hours.

After the encapsulation reaction, the obtained capsule dispersion is directly diluted with water so as to have a predetermined drug substance concentration, and if necessary, a suspension stabilizer is added to obtain a stable slurry type preparation.

Further, when it is necessary in hygiene to remove and reduce the remaining free formaldehyde after forming the microcapsule wall film, urea, ethylene urea, sulfite, saccharide, ammonia, amine, formamide, Addition of hydroxyamine salts (hydrochlorides, sulfates, phosphates), melamine, compounds with active methylene groups, hydroxyalkylamines, acrylamides, acrylamide copolymers, etc. and formaldehyde-innocuous substances under appropriate reaction conditions It is possible to remove the residual formaldehyde by changing to.

As a suspension stabilizer for the capsule slurry,
Natural polysaccharides such as xanthan gum and locust bean gum,
Semi-synthetic polysaccharides such as carboxymethyl cellulose and hydroxypropyl cellulose, synthetic polymers such as polyacrylic acid sodium salt, magnesium aluminum silicate, mineral fine powder such as high-purity bentonite, etc., used alone or in combination of two or more. To be done. These thicken and stabilize the capsule slurry.

Further, in order to improve suspension stability and dispersion stability, lignin sulfonate, formalin condensate of sodium naphthalene sulfonate, polyoxyethylene alkylallyl sulphate salt, polyoxyethylene styryl phenyl ether sulphate salt, Anionic surfactant such as polyoxyethylene nonyl ether sulfate salt, nonionic surfactant such as polyoxyethylene nonyl phenyl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene alkyl allyl ether, etc. are blended alone or in a mixture. It is also possible.

The average particle size of the prepared microcapsules is determined depending on the kind and concentration of the dispersant used during suspension dispersion and the strength of mechanical stirring during suspension dispersion, but usually 5 to 80 μm. It is desirable to adjust to the range of, preferably 5 to 50 μm.

The weight ratio of melamine-formaldehyde or its derivative used in the present invention to the core substance is 1:50.
0 to 1:20 is preferable. The thickness of the wall film of the microcapsule varies depending on the volume ratio of the core substance and the water-soluble capsule wall precursor, but is determined by the following approximate expression. That is, the average particle size of the microcapsules is d, the weight of the core substance is W _C , the weight of the membrane substance is W _W , the density of the membrane substance is ρ _W ,
When the density of the core substance is ρ _C , it is calculated by the following formula.

[0034]

[Equation 1] The film thickness of the microcapsules according to the present invention is 10 to 500 nm.
It is preferable to adjust to a range of 20 to 300 nm.

When the composition of the present invention is used for controlling pests in paddy fields, vegetable fields, orchards, etc., these can be diluted with water to a predetermined concentration and then applied. In this case, even when the same active ingredient concentration is applied, the drug efficacy is retained for several weeks, which is several times that of existing formulation types such as emulsions. Further, even when compared to a microcapsule agent having a different kind of wall film, it is excellent in both initial activity and residual effect,
Further, even when compared with a microcapsule having a wall membrane, by keeping the weight of the wall membrane relative to the core substance and the size of the microcapsule particles in the optimum range, not only the initial activity but also the long-term activity can be retained. It is possible.
From the above points, the present insecticidal composition retains the activity for a long period of time as compared with the existing preparations described above, and thus is very useful in terms of labor saving by reducing the number of times of spraying or reducing the amount of sprayed medicine. It is something. Further, the composition of the present invention can reduce the toxicity of a synthetic pyrethroid agent having high fish toxicity, and is useful as a highly safe preparation even when these compounds are applied to paddy fields.

[0036]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, Comparative Examples and Test Examples, but the present invention is not limited to these. Example 1 To 104.3 g of pure water, 38.56 g of an anionic polymer surfactant (20% by weight aqueous solution of a copolymer containing acrylic acid, acrylonitrile and acrylmethyluropansulfonic acid at 60, 40 and 10 mol% respectively) was added. Dissolve and p with 5N NaOH
Adjust H to around 4. Furthermore, to this solution, as a capsule wall precursor, Euramine T-34 (manufactured by Euramine Industries;
Methylated methylol melamine) was added 2.90 g (1.5% in solid content relative to the core substance), and as the core substance, Compound 1 and VINYCISER 100 (Kao's product; alkyl phthalate alkyl ester having 10 carbon atoms) ) Weight ratio of 50:
154.24 g of mixed lysate of 50 was added and T. K. The hydrophobic solution was emulsified and dispersed for several minutes at a rotation speed of 5000 rpm using an automixer (trade name of Tokushu Kika Kogyo Co., Ltd.). Then, the mixture was allowed to react in a constant temperature bath at 60 ° C. for 2 to 3 hours with gentle stirring to obtain a dispersion liquid of the microencapsulated product. Kerzan S (Tri-Crystal Co., Ltd .: xanthan gum) and Jaguar 81 so that the final concentration is 0.05% each
A predetermined amount of a mixed solution of 11 (Sansho Co., Ltd .: guar gum) was added to obtain a microcapsule slurry of Compound 1 having an active ingredient concentration of 20% by weight and an average particle diameter of 30 μm. Example 2 As a core substance, 154.24 g of a mixed solution of Compound 1 and VINYCIZER 124 (Kao's product; a phthalic acid alkyl ester mixture having an alkyl group having 10 to 12 carbon atoms) in a weight ratio of 50:50.
In addition, the same operation as in Example 1 was performed to obtain an active ingredient concentration of 20.
A microcapsule slurry of Compound 1 having a weight percentage of 30 μm and an average particle diameter of 30 μm was obtained. Example 3 3.08 g of Euramine T-34 as a capsule wall precursor
(The solid content ratio is 2.0% with respect to the core substance.) As the core substance, compound 1 and DINP (Kyowa Hakko Co., Ltd .; an alkyl phthalate alkyl ester having 9 carbon atoms) in a weight ratio of 50:50.
154.24 g of a mixture dissolved in the proportion of was added and the same operation as in Example 1 was carried out.
A 30 μm Compound 1 microcapsule slurry was obtained. Example 4 3.08 g of Euramine T-34 as a capsule wall precursor,
As the core substance, 154.24 g of compound 1 and DnOP (Wako Pure Chemical Industries, Ltd .; phthalic acid alkyl ester having an alkyl group having 8 carbon atoms) mixed and dissolved at a weight ratio of 50:50 were added,
The same operation as in Example 1 was performed to obtain a microcapsule slurry of Compound 1 having an active ingredient concentration of 10% by weight. Example 5 3.08 g of Euramine T-34 as a capsule wall precursor,
As a core substance, Compound 1 and Vinizer 100 are used in a weight ratio of 5
Add 154.24 g of the mixture dissolved at a ratio of 0:50, and add TK
The same operation as in Example 1 was carried out except that the number of revolutions of the auto homomixer was changed to 7,000 rpm to obtain a microcapsule slurry of Compound 1 having an active ingredient concentration of 20% by weight and an average particle size of 20 μm. Example 6 The same operation as in Example 5 was carried out except that the number of revolutions of the TK autohomomixer was set to 4000 rpm to obtain a microcapsule slurry of Compound 1 having an active ingredient concentration of 20% by weight and an average particle size of 40 μm. .. Example 7 A microcapsule slurry of Compound 1 having an active ingredient concentration of 20% by weight and an average particle size of 15 μm was obtained by performing the same operation as in Example 5 except that the rotation speed of the TK autohomomixer was set to 8000 rpm. .. Example 8 The same procedure as in Example 1 was carried out except that Euramin T-33 (manufactured by Euramine Industrial Co .; methylated methylol melamine) was used as a precursor for the capsule wall to make 2.90 g of the active ingredient concentration.
A 20% by weight, microcapsule slurry of Compound 1 having an average particle size of 30 μm was obtained. Example 9 As a core substance, Compound 1 and Hysol SAS-296 (Nippon Petrochemical Co., Ltd .; Phenylxylylethane) in a weight ratio of 50:
Except for adding 154.24 g of mixed and dissolved at a ratio of 50,
The same operation as in Example 5 was carried out to obtain an active ingredient concentration of 20% by weight,
A microcapsule slurry of Compound 1 having an average particle size of 20 μm was obtained. Example 10 As a core substance, Compound 1 and Vinizer 100 were used in a weight ratio of 5
The same operation as in Example 5 was carried out except that 154.24 g of a mixture dissolved at a ratio of 0:50 was added to obtain a microcapsule slurry of Compound 3 having an active ingredient concentration of 20% by weight and an average particle size of 20 μm. .. Example 11 As the core substance, the same operation as in Example 5 was carried out except that 154.24 g of a mixture of fenvalerate and Vinizerizer 100 in a weight ratio of 40:60 was dissolved.
A fenvalerate microcapsule slurry with 10% by weight and an average particle size of 20 μm was obtained. Example 12 As the core substance, the same operation as in Example 5 was carried out except that 154.24 g of a mixture of permethrin and Vinysizer 124 mixed and dissolved in a weight ratio of 30:70 was added and dissolved, and the active ingredient concentration was 10% by weight, and the average. A microcapsule slurry of permethrin with a particle size of 20 μm was obtained. Example 13 0.77 g of Euramine T-34 as a capsule wall precursor
(The solid content ratio is 0.5% with respect to the core substance.) As the core substance, Compound 2 and VINYCISER 105 (Kao's product; alkyl phthalate alkyl ester having 10 carbon atoms) are in a weight ratio of 25:75. 154.24 g of the mixed and dissolved in
Rotation speed of TK Auto Homo Mixer during emulsion dispersion is 9000 r
The same operation as in Example 1 was carried out except that pm was used to obtain a microcapsule slurry of Compound 2 having an active ingredient concentration of 10% by weight and an average particle size of 10 μm. Example 14 1.54 g of Euramine T-34 as a capsule wall precursor
(Except for the solid content of 1.0% of the core substance),
Perform the same operation as in Example 13, 10% by weight of the active ingredient concentration,
A microcapsule slurry of compound 2 having an average particle size of 10 μm was obtained. Example 15 The rotation speed of the TK Auto Homomixer at the time of emulsifying and dispersing was 10,000 r
The same operation as in Example 14 was carried out except that pm was used to obtain a microcapsule slurry of Compound 2 having an active ingredient concentration of 10% by weight and an average particle size of 5 μm. Example 16 The same operation as in Example 14 was conducted except that 77 g of a 5% by weight aqueous solution of ethylene-maleic anhydride copolymer was added as an anionic polymer surfactant, and the active ingredient concentration was 5% by weight.
A microcapsule slurry of compound 2 having an average particle size of 10 μm was obtained. Comparative Example 1 Compound 1 and VINYCISER 100 were mixed and dissolved in a weight ratio of 50:50 and dissolved in 100 g of olestar NP-2000 (hexamethylene diisocyanate; Mitsui Toatsu Chemical Co., Ltd.) 2.7 g. The entire amount of the composition was added to 50 g of an aqueous solution of PVA-217 (polyvinyl alcohol; Kureha Chemical Co., Ltd.), and the mixture was stirred and emulsified for several minutes at a rotation speed of 5000 rpm using a TK Auto Homomixer. Then add hexamethylenediamine to 0.25
After adding pH and adjusting the pH to 9 or more, the mixture was gently reacted at 50 ° C. for 2 hours to obtain a dispersion liquid of a microencapsulated product having polyurea as a wall film. A predetermined amount of a mixed solution of Kelzan S and Jaguar 8111 was added to each so that the final concentration was 0.05% to obtain a microcapsule slurry of Compound 1 having an active ingredient concentration of 20% by weight and an average particle size of 30 μm. Comparative Example 2 The rotation speed of the TK Auto Homomixer during emulsification and dispersion was 7,000 r.
The same operation as in Comparative Example 1 was carried out except that pm was used to obtain a microcapsule slurry of Compound 1 having an active ingredient concentration of 20% by weight. Comparative Example 3 3.0 g of methylene diisocyanate was dissolved in 100 g of a mixture of Compound 1 and Vinizer 100 mixed in a weight ratio of 50:50, and the total amount of this composition was added to 200 g of a 0.5% PVA-217 aqueous solution to prepare TK. The mixture was stirred and emulsified for several minutes at a rotation speed of 5000 rpm using an auto homomixer. Next, add 4.5 g each of ethylenediamine and diethylenetriamine, and add 62 g of ion-exchanged water in which 12.8 g of sodium carbonate is dissolved, and add at 50 ° C.
After gently reacting for 2 hours, a dispersion liquid of microencapsulated product having polyamide as a wall film was obtained. A predetermined amount of a mixed solution of Kelzan S and Jaguar 8111 was added to each to give a final concentration of 0.05% to obtain a microcapsule slurry of Compound 1 having an active ingredient concentration of 20% by weight and an average particle diameter of 30 μm. Comparative Example 4 The same operation as in Comparative Example 3 was conducted except that 1.5 g of methylene diisocyanate was added, 4.3 g of ethylenediamine and diethylenetriamine were added, and 62 g of ion-exchanged water in which 6.4 g of sodium carbonate was dissolved was added. A microcapsule slurry of Compound 1 having a component concentration of 20% by weight and an average particle size of 30 μm was obtained. Comparative Example 5 As the core substance, Compound 1 and Vinizer 100 were used in a weight ratio of 5
What was mixed and dissolved at a ratio of 0:50 was emulsified and dispersed using PVA-217 (Kureha Co., Ltd .; polyvinyl alcohol), and the same operation as in Example 1 was carried out, but a microcapsule slurry was obtained. I could not do it. Comparative Example 6 12.34 g of Euramine T-34 as a precursor for capsule wall
(The solid content is 8% with respect to the core substance).
The same operation as in Example 5 was carried out except that 154.24 g of a mixture of Compound 1 and Vinizer 100 in a weight ratio of 50:50 was mixed and dissolved, and the active ingredient concentration was 20% by weight and the average particle size was 20.
A microcapsule slurry of Compound 1 of μm was obtained. Comparative Example 7 18.51 g of Euramine T-34 as a precursor for capsule wall
(The solid content is 12% with respect to the core substance), as the core substance,
The same operation as in Example 1 was carried out except that 154.24 g of a mixture of Compound 1 and Vinizer 100 in a weight ratio of 50:50 was dissolved, and the active ingredient concentration was 20% by weight and the average particle size was 30.
A microcapsule slurry of Compound 1 of μm was obtained. Comparative Example 8 15.42 g of Euramine T-34 as a precursor for capsule wall
(10% of the core material in terms of solid content), as the core material,
The same operation as in Example 13 was carried out except that 154.24 g of a mixture of Compound 2 and Vinizer 105 mixed and dissolved in a weight ratio of 25:75 was added, and the active ingredient concentration was 10% by weight and the average particle size was 10
A microcapsule slurry of Compound 2 of μm was obtained. Comparative Example 9 23.14 g of Euramine T-34 as a precursor for capsule wall
(15% of the core substance in terms of solid content), as the core substance,
The same operation as in Example 15 was carried out except that 154.24 g of a mixture of Compound 2 and Vinizer 105 mixed and dissolved at a weight ratio of 25:75 was added, and the active ingredient concentration was 10% by weight and the average particle size was 5
A microcapsule slurry of Compound 2 of μm was obtained. Comparative Example 10 As a core substance, a mixture of Compound 2 and dimethyl phthalate (Wako Pure Chemical Industries, Ltd .; phthalic acid alkyl ester having an alkyl group having 1 carbon atom) in a weight ratio of 50:50 was dissolved.
The same operation as in Example 13 was carried out except that 24 g was added, to obtain a microcapsule slurry of Compound 2 having an active ingredient concentration of 10% by weight and an average particle size of 10 μm. Comparative Example 11 As a core substance, a mixture of compound 2 and dimethyl phthalate (Wako Pure Chemical Industries, Ltd .; an alkyl phthalate alkyl ester having 2 carbon atoms) at a weight ratio of 50:50 was dissolved.
The same operation as in Example 13 was carried out except that 24 g was added, to obtain a microcapsule slurry of Compound 2 having an active ingredient concentration of 10% by weight and an average particle size of 10 μm. Comparative Example 12 Trebone emulsion (20%) (commercial product; existing formulation containing Compound 1) Comparative Example 13 10 parts by weight of Compound 2 and 4 parts by weight of Solpol 355F (manufactured by Toho Kagaku Co., Ltd.) were mixed to give 86 parts by weight of xylene. Dissolves in
100 parts by weight of the emulsion of compound 2 was obtained. Comparative Example 14 Paidrin emulsion (30%) (overseas product; existing formulation containing fenvalerate) Comparative Example 15 Adeion emulsion (20%) (commercial product; existing formulation containing permethrin) Comparative Examples 1, 2, 3, 4 Shows a microencapsulated insecticidal composition having different wall membrane components for the present invention.

In Comparative Example 5, the polymeric surfactant is a nonionic surfactant.

Comparative Examples 6, 7, 8 and 9 are examples in which the weight ratio of the core substance solution to the microcapsule wall film is outside the range of claim 6.

Comparative Examples 10 and 11 are examples in which the carbon number of the alkyl group of the phthalic acid alkyl ester in the core substance is outside the range of claim 5.

Comparative Examples 12, 13, 14, and 15 show emulsions of each compound, which is one of the existing dosage forms. Test Example Test Example 1 Examples 1, 2, 3, 5, 8, 10 and Comparative Examples 1, 4, 6,
The composition obtained in Example 7 and Comparative Example 12 were subjected to an insecticidal effect test against the planthopper planthopper. The test method is 1 /
Five paddy rice plants are transplanted as a bundle into a resin pot of 10,000 are and grown in a greenhouse for about 1 to 2 weeks until the leaf age reaches 4 to 5 leaves. The microencapsulated insecticidal compositions obtained in Examples and Comparative Examples and the trevone emulsion of Comparative Example 10 were diluted with water so that the active ingredient concentration was 100 ppm, and sprayed on paddy rice. This was covered with a wire netting cage, and 10 adults of the flying squirrel planthopper were released in the cage every predetermined number of days, and life or death was determined 24 hours later. The test was repeated 3 times. The results are shown in Table 1.

[0041]

[Table 1] Test Example 2 With respect to the compositions obtained in Examples 13, 15, and 16 and Comparative Examples 8, 9, and 13, a drug efficacy test against Nymphalid mites was performed.
As the test method, the emulsions of compound 2 obtained in the examples and comparative examples were diluted with water so that the active ingredient concentration was 25 ppm, sprayed on potted kidney beans, and kept in a greenhouse.
Cut out the leaves of the kidney bean into 2 cm squares every predetermined number of days,
It was placed on a Petri dish and 10 test insects were released on it.

Life or death was determined 48 hours after being released. In addition,
The test was performed in duplicate. The results are shown in Table 2.

[0043]

[Table 2] Test Example 3 The carp toxicity test was conducted on the compositions obtained in Examples 11, 12, and 13 and Comparative Example 11, and Comparative Examples 12 and 13.
In the test method, the composition was added to a cylindrical glass water tank containing 10 L of dechlorinated tap water so that the active ingredient concentration of each composition was 5 ppm, and then sufficiently stirred. Ten of each carp fry with a body length of 4-5 cm was released into this aquarium, and the number of deaths 48 hours later was investigated. The results are shown in Table 3.

[0044]

[Table 3] From the above results, the composition of the present invention is a composition having a conventional formulation type or a microcapsule composition coated with another wall film, and further a capsule coating weight ratio exceeding the optimum range even when a melamine derivative is used. It shows high insecticidal activity over a long period of time, and significantly reduces and improves toxicity to aquatic animals.

[0045]

As described above, the microencapsulation of the pyrethroid insecticide having the wall film of melamine-formaldehyde or its derivative of the present invention is a formulation type which exhibits an extremely stable insecticidal effect over a long period of time. It is extremely useful as a dosage form which is remarkably reduced in toxicity to aquatic animals and which can sufficiently exert the performance of the insecticidal active ingredient.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Imakita 1144 Togo, Mobara-shi, Chiba Prefecture Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Yuji Enomoto 1144 Togo, Mobara-shi, Chiba Prefecture Mitsui Toatsu Chemical Co., Ltd. (72) Toshio Matsumoto 1144 Togo, Mobara-shi, Chiba Prefecture Mitsui Toatsu Chemical Co., Ltd.

Claims (15)

[Claims] 1. A liquid pyrethroid insecticide or a hydrophobic solution obtained by dissolving or compatibilizing a pyrethroid insecticide in a high boiling point solvent is used as a core substance, and melamine-formaldehyde, a methylolmelamine monomer or a low molecular weight polymer thereof, an alkyl group. 1 selected from the group consisting of a modified methylol melamine monomer or a low molecular weight polymer thereof and a combination thereof.
A water-suspended microcapsule insecticidal composition comprising a thin film obtained by polycondensing at least one species as a wall film. 2. A pyrethroid insecticide is represented by the general formula (1): (In the formula, X represents an oxygen atom or a methylene group, R represents a lower alkyl group or a halomethyl group, and R ₁ represents a hydrogen atom or a fluorine atom.) Composition. 3. The microcapsule insecticidal composition according to claim 1, wherein the pyrethroid insecticide is 2- (4-ethoxyphenyl) -2-methylpropyl 3-phenoxybenzyl ether (ethofenprox). 4. The microcapsule insecticidal composition according to claim 1, wherein the pyrethroid insecticide is 2- (4-difluorobromomethoxyphenyl) -2-methylpropyl 3-phenoxybenzyl ether. 5. The high boiling point solvent is an alkyl group having 8 to 8 carbon atoms.
The microcapsule insecticidal composition according to claim 1, wherein the phthalic acid alkyl ester is 13. 6. The weight ratio of the core substance to the wall membrane is 500: 1 to 20:
The microcapsule insecticidal composition according to claim 1, which is 1. 7. The average particle size of the microcapsule particles is 5 to 5.
The microcapsule insecticidal composition according to claim 1, which is in a range of 80 μm. 8. One or more selected from the group consisting of melamine-formaldehyde, a methylol melamine monomer or a low molecular weight polymer thereof, an alkylated methylol melamine monomer or a low molecular weight polymer thereof, and a combination thereof. It is dissolved in water containing an anionic polymer surfactant, and in that solution, a liquid pyrethroid insecticide or a hydrophobic solution in which a pyrethroid insecticide is dissolved or compatibilized in a high boiling point solvent is added to emulsify and disperse it. The water-suspended microcapsule insecticidal composition according to claim 1, wherein the melamine monomer and / or the low molecular weight polymer is polycondensed around the emulsified particles to form a wall film by heating. Method of manufacturing things. 9. The anionic polymer surfactant is (A) acrylic acid or methacrylic acid, (B) acrylonitrile or methacrylonitrile, (C) acrylamidoalkylsulfonic acid or a sulfoalkyl ester of acrylic acid,
9. The method for producing a microcapsule insecticidal composition according to claim 8, which is an anionic water-soluble polymer surfactant obtained by blending at least one kind from each of the monomers and polymerizing. 10. A pyrethroid insecticide having the general formula (1): 9. In the formula, X represents an oxygen atom or a methylene group, R represents a lower alkyl group or a halomethyl group, and R ₁ represents a hydrogen atom or a fluorine atom. Method of manufacturing things. 11. The method for producing a microcapsule insecticidal composition according to claim 8, wherein the pyrethroid insecticide is etofenprox [2- (4-ethoxyphenyl) -2-methylpropyl 3-phenoxybenzyl ether]. 12. The method for producing a microcapsule insecticidal composition according to claim 8, wherein the pyrethroid insecticide is 2- (4-difluorobromomethoxyphenyl) -2-methylpropyl 3-phenoxybenzyl ether. 13. The high boiling point solvent has an alkyl group having 8 carbon atoms.
9. The method for producing a microcapsule insecticidal composition according to claim 8, wherein the phthalic acid alkyl ester is from 1 to 13. 14. The weight ratio of the core substance to the wall film is 500: 1 to 2
The method for producing a microcapsule insecticidal composition according to claim 8, wherein the ratio is 0: 1. 15. The average particle size of the microcapsule particles is 5.
The method for producing a microcapsule insecticidal composition according to claim 8, wherein the microcapsule insecticidal composition has a size in the range of -80 μm.