JPH0676286B2 - Agricultural insecticidal and acaricidal composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a microcapsule composed of a polyurea-based coating, which is a pyrethroid insecticide and acaricide, and has an average particle size of 80 μm or less and a film thickness. Of 0.3 μm or less and (average particle size / film thickness) of 250 or more, and is encapsulated in a polyurea-based coating, which is capable of exerting an excellent residual effect. It is about things.

<Prior Art> Pyrethroid insecticides and acaricides generally have fast-acting and high insecticidal and acaricidal effects, and can be used as emulsions, oils, wettable powders,
It is formulated into powders and other dosage forms and is used as an agricultural insecticide and acaricide, but in some cases it has a low residual effect and is expensive, so it is possible to find a more economical method of use. Is expected.

In addition, many pyrethroid insecticides and acaricides have relatively high fish venom, and it is difficult to reduce this fish venom when formulated into a formulation such as emulsion, oil, wettable powder, powder. ,
Development of a fish poison reduction formulation is also desired.

In general, when insecticides and acaricides are microencapsulated, the active ingredient is encapsulated as a core substance of the microcapsules and isolated from the environment outside the membrane, so that they are not easily decomposed by microorganisms, moisture, light and the like. Further, the release of the active ingredient out of the membrane is controlled by the presence of the membrane, so that it is released.

Micro-encapsulated insecticide for the above two reasons,
Acaricides often have better residual effect than non-encapsulated ones, for example, Japanese Patent Publication No. 55-38235.
The invention described in Japanese Patent Publication No. JP-A No. 2003-242242 relates to a pyrethroid insecticidal composition obtained by microencapsulating a pyrethroid insecticide with a polyurethane coating, but the residual effect of microencapsulation in the examples is It is described that the property is excellent.

Thus, in many cases, the residual effect tends to be improved when the insecticide and acaricide are encapsulated in microcapsules.

<Problems to be solved by the invention> However, even if the same insecticide and acaricide are encapsulated with the same membrane substance, a certain residual effect cannot always be expected. There was a difference.

In general, microencapsulation tends to reduce the fish poison of insecticides and acaricides, but the reduction rate may differ between the microcapsules.

Therefore, as a result of diligent studies, the present inventors have found that various factors constituting the microcapsule, particularly particle size and film thickness, have a serious influence on the reduction of residual efficacy and fish toxicity,
The present invention has been completed.

<Means for Solving Problems> The present inventors diligently studied conditions under which the residual effect is particularly excellent when microencapsulating an agricultural pyrethroid insecticide and acaricide with a polyurea coating. As a result, when microencapsulating agricultural pyrethroid insecticides and acaricides with a polyurea coating, the average particle size of the microcapsules was set to 80 μm or less, and the upper film thickness was set to 0.3 μm or less, and It has been found that when the (diameter / film thickness) is 250 or more, the residual effect is particularly good and the fish poison is reduced. The method of microencapsulation is, for example, after suspending a hydrophobic liquid containing a polyfunctional isocyanate and an organophosphorus insecticide in an aqueous solution containing a water-soluble polymer as a suspension dispersant in the form of microdroplets. The polymerization reaction is caused by heating as it is to react with water or by adding a polyvalent amine having two or more amino groups and heating. After the encapsulation reaction, the obtained capsule dispersion is diluted as it is with pure water so as to have a predetermined drug substance concentration, and if necessary, a dispersion stabilizer is added to obtain a stable slurry type preparation. When an excess of amine is used in the polymerization, after the reaction, for example,
You may neutralize with HCl etc.

Examples of the polyvalent amine having two or more NH ₂ groups include ethylenediamine, hexamethylenediamine, phenylenediamine, toluenediamine, diethylenetriamine and the like.

Examples of polyfunctional isocyanates include toluene diene
Isocyanate, hexamethylene diisocyanate,
Ruene diisocyanate and trimethylolpropane
Self-condensation of adduct, hexamethylene diisocyanate
Thing, and Sumidule L (Sumitomo Bayer Urethane Co., Ltd.
Formula company), Sumidur N (Sumitomo Bayer Urethane
(Made by a corporation).

On the other hand, as the composition of the hydrophobic liquid, when the polyfunctional isocyanate and the pyrethroid insecticide, the acaricide are dissolved, a mixture of these two can be directly used,
If they are not soluble in each other, choose one that can dissolve polyfunctional isocyanate and pyrethroid insecticide and acaricide in an organic solvent that is not miscible with water, and select one of the three (polyfunctional isocyanate, pyrethroid insecticide). , Acaricide, solvent)
It is desirable to use a homogeneous mixture of Examples of the organic solvent used for this purpose include hydrocarbons such as xylene, toluene, alkylbenzene, phenylxylylethane, hexane and heptane, chlorinated hydrocarbons such as chloroform, methyl ethyl ketone, cyclohexanone, etc. It can be selected from ketones, esters such as diethyl phthalate and n-butyl acetate. Pyrethroid insecticides, acaricides and dispersants for suspending and dispersing hydrophobic solutions containing polyfunctional isocyanates include natural polysaccharides such as gum arabic, carboxymethylcellulose, semisynthetic polysaccharides such as methylcellulose, and polyvinyl alcohol. Synthetic polymers such as, and fine powders of minerals such as magnesium and aluminum silicate are used alone or in combination of two or more. When the suspension dispersibility is weak, the suspension dispersibility can be improved by adding a known surfactant described in “Synthetic Surfactant” by Hiroshi Horiguchi. As the dispersion stabilizer of the capsule slurry, the water-soluble polymers listed as the above-mentioned dispersants may be used as they are, but if necessary, natural polysaccharides such as xanthan gum and locust bean gum, carboxymethyl cellulose and the like. Semi-synthetic polysaccharides, synthetic polymers such as sodium polyacrylate, magnesium
Mineral fine powder such as aluminum silicate may be used alone or in combination of two or more as a thickener.

Examples of pyrethroid insecticides and acaricides include fenvalerate (α-cyano-3-phenoxybenzyl α-isopropyl-4′-chlorophenylacetate) and fenpropasulin (α-cyano-3-phenoxybenzyl).
2,2,3,3-Tetramethylcyclopropanecarboxylate), permethrin (3-phenoxybenzyl 2,2-
Dimethyl-3- (2,2-dichlorovinyl) cyclopropane-1-carboxylate), cypermethrin (α-cyano-3-phenoxybenzyl 3- (2,2-dichlorovinyl) -2,2-dimethylcyclopropane Carboxylate), tetramethrin (3,4,5,6-tetrahydrophthalimidomethyl chrysanthemate), allethrin (3-
Allyl-2-methylcyclopent-2-en-4-one-1-yl cis, trans-chrysanthemate), phenothrin (3-phenoxybenzyl cis, trans-chrysanthemate), deltamethrin (α-cyano-
3-phenoxybenzyl 3- (2,2-dipromovinyl) -2,2-dimethylcyclopropanecarboxylate), cyhalothrin (α-cyano-3-phenoxybenzyl 2,2-dimethyl-3- (3,3,3-) Trifluoro-
2-chloro-propenyl) -cyclopropanecarboxylate) and isomers thereof, natural pyrethrin, and the like, but are not limited thereto.
Of course, it is also possible to use a mixture of these different pyrethroid insecticides, acaricides and pyrethroid insecticides, acaricides and pyrethroid insecticides, insecticides other than acaricides, and a mixture of acaricides. . In addition, synergists such as piperonyl butoxide and commonly used BH
Stabilizers such as T (2,6-di-t-butyl-4-methylphenol) can also be added.

The average particle size of the microcapsules is determined by the type and concentration of the dispersant used for suspension dispersion, and the strength of mechanical stirring during suspension dispersion. For the measurement of the average particle size, for example, a Coulter Counter Model TA-II type (a product handled by Nikkaki) can be used.

The film thickness of the microcapsules varies depending on the ratio of the volume of the core substance to the volume of the film substance, but can be obtained by the following approximate expression. That is, if the weight of the core substance of the microcapsule is Wc, the weight of the membrane substance is Ww, the density of the membrane substance is ρw, the density of the core substance is ρc, and the average particle diameter of the core substance is d. Becomes

The film thickness referred to in the present invention is calculated using this equation.

<Example> Next, the present invention will be described in more detail with reference to Examples, Comparative Examples and Test Examples.

Example 1 Sumidule L 4g (same as above) and phenyloxy
Lilethane (Product name Hysol SAS296 ; Japan Petrochemical
(Made by Co., Ltd.) 100g added to 100g fenvalerate, uniform
Stir until it becomes a different solution and add it to polyvinyl alcohol.
(Product name Gohsenol GL-05 ; Nippon Synthetic Chemical Industry Co., Ltd.
(Made by company) Add to 400 g of 10 wt% aqueous solution and add microdroplets at room temperature
T.K. Auto Homo Mixer (Special Machine Industry Co., Ltd.
The company brand name) was used and stirred for several minutes. Rotation speed is 1250rp
It was m.

Then, the mixture was allowed to react in a constant temperature bath at 60 ° C. for 24 hours with gentle stirring to form a dispersion liquid of the microencapsulated product.

Pure water was added to this to prepare a total weight of 1000 g, and a fenvalerate capsule slurry having an active ingredient concentration of 10% by weight was obtained (composition 1).

The average particle size of the obtained microcapsules is 50 μm, and the film thickness is
0.109 μm, average particle size / film thickness) was 459.

Example 2 The rotation speed of the TK auto homomixer (same as above) was set to 6500.
The same operation as in Example 1 was carried out except that the rpm was changed to obtain a fenvalerate capsule slurry having an active ingredient concentration of 10% by weight (present composition 2).

The average particle size of the obtained microcapsules is 50 μm, and the film thickness is
The average particle size / film thickness was 0.011 μm, which was 455.

Example 3 Sumidule L (Same as above) to 0.8g, T.K.
Rotating speed of the auto homomixer (same as above) is 6500 rpm
The same operation as in Example 1 was performed except that the active ingredient concentration was increased.
10% by weight fenvalerate capsule slurry was obtained
(This composition 3).

The average particle size of the obtained microcapsules is 5 μm, and the film thickness is
The average particle size / film thickness was 0.002 μm and 2500.

Example 4 Sumidule L (Same as above) to 0.2g, T.K.
Rotating speed of the auto homomixer (same as above) to 2300 rpm
The same operation as in Example 1 was performed except that the active ingredient concentration was increased.
10% by weight fenvalerate capsule slurry was obtained
(This composition 4).

The average particle size of the obtained microcapsules is 20 μm, and the film thickness is
The average particle size was 0.002 μm and the average particle size / film thickness was 10,000.

Example 5 Sumidule L (Same as above) to 4 g, femba
Fenpropasulin was used instead of Relate, and T.K.
Rotating speed of the auto homomixer (same as above) is 6500 rpm
The same operation as in Example 1 was performed except that the active ingredient concentration was increased.
10% by weight of Fenpropasulin capsule slurry
(This composition 5).

The average particle size of the obtained microcapsules is 5 μm, and the film thickness is
0.011 μm (average particle size / film thickness) was 455.

Example 6 Sumidule L 1.5g (same as above)
Add to 200 g of the mixture and heat to stir until it becomes a uniform solution.
Water containing 5% by weight of gum arabic as an emulsifying dispersant
Add to 350 g of the solution and add T.K.
A homogenizer (same as above) and stir for a few minutes.
It was The rotation speed was 8500 rpm. Then, in a constant temperature bath at 80 ℃ 2
If the reaction is performed with gentle stirring for 0 hours, a microcap
A cellized dispersion was formed. Add pure water to this and
Prepared to a weight of 1000g, 20% by weight active ingredient concentration
Fenvalerate capsule slurry of
6).

The average particle size of the obtained microcapsules is 15 μm, and the film thickness is
0.013 μm, (average particle size / film thickness) was 1154.

Example 7 Sumidule L Add the amount of (the same as above) to 1 g,
Replacing 200 g of phenate with 200 g of fenpropasulin, T.K.
Rotating speed of the homotomixer (same as above) to 5500 rpm
The same operation as in Example 7 was performed except that the
20% by weight of Fenpropasulin capsule slurry
(This composition 7).

The average particle size of the obtained microcapsules is 50 μm, and the film thickness is
0.03 μm, (average particle size / film thickness) was 1667.

Example 8 Sumidule L 4g (same as above) and Hisol SA
S-296 Add 100g (same as above) to 100g of permethrin
Stir until a homogeneous solution is obtained and add 5% by weight of arabic
Add it to 350g of an aqueous solution containing gum as an emulsifying dispersant and add at room temperature.
T.K. auto homomixer (see above
The same) was stirred for several minutes. The rotation speed at that time is 8000 rpm
there were. Then, gently stir in a constant temperature bath at 55 ° C for 30 hours.
While reacting, a dispersion liquid of the microencapsulated product is produced.
I started. Add pure water to this so that the total weight becomes 1000 g
Then, add 0.3% by weight of zanthan gum and
Thickener containing 0.6% by weight of sium aluminum silicate
Diluted 2 times with the solution, and the active ingredient concentration is 5% by weight.
A microcapsule slurry was obtained (the present composition 8).

The average particle size of the obtained microcapsules is 20 μm, and the film thickness is
0.044 μm, (average particle size / film thickness) was 455.

Example 9 Sumidule L 2g (same as above) and 100g Shikiren
Is added to 100 g of cypermethrin and stirred until a uniform solution is obtained.
Then, 5% by weight of gum arabic was added as an emulsifying dispersant.
Add to 350 g of aqueous solution and add T.K.
A homogenizer (same as above) and stir for a few minutes.
It was The rotation speed at that time was 5,500 rpm. Then Echire
In a constant temperature water bath at 70 ℃ after dropping 6g of diamine
If the reaction is carried out with gentle stirring for 24 hours,
A dispersion of the pselized product formed. Using 1N hydrochloric acid solution
After adjusting the pH of the system to 7, add pure water to bring the total weight to 10
Prepared so that it will be 00g, the active ingredient concentration of 10% by weight
A methrin capsule slurry was obtained (present composition 9).

The average particle size of the obtained microcapsules is 50 μm, and the film thickness is
0.065 μm, (average particle size / film thickness) was 769.

Example 10 Sumidule L (Same as above) 2g instead of sumiju
Le N 2g (same as above), 100g of cypermethrin
Replace with 100 g of tetramethrin and 6 g of ethylenediamine
Using 6 g of nylene diamine, the T.K.
The same operation as in Example 9 was performed except that the number of revolutions was set to 8000 rpm.
Not available, Tetramethrin capsules with 10% active ingredient concentration
A slurry was obtained (this composition 10).

The average particle size of the obtained microcapsules is 20 μm, and the film thickness is
The average particle diameter / film thickness was 0.027 μm and 741.

Example 11 Sumidule L 1g (same as above) and 50g xylene
Was added to 150 g of allethrin and stirred until a uniform solution was obtained,
Water containing 5% by weight of gum arabic as an emulsifying dispersant
Add to 350 g of the solution and add T.K.
Stir for a few minutes using Tohomomixer (same as above)
It was The rotation speed was 8000 rpm. Then a constant temperature water bath at 60 ° C
The reaction is carried out in a micro
A dispersion of encapsulated material resulted. Add pure water to this
Prepare the body weight to be 1000g, 4% by weight
Carboxymethyl cellulose (Serogen 3H , Daiichi Kogyo
Pharmaceutical Co., Ltd.) Active ingredient concentration 7.
5% by weight of Allethrin capsule slurry was obtained (this composition
Things 11).

The average particle size of the obtained microcapsules is 20 μm, and the film thickness is
0.01 μm, (average particle size / film thickness) was 2000.

Example 12 Sumidule L (Same as above) Change to single
L 0.8g (same as above) and toluene diisocyanate
Nate (Sumijour T80 , Sumitomo Bayer Urethane Co., Ltd.
(Company) 0.1g, replace fenvalerate with pheno
Using Surin, T.K. auto homomixer (same as above)
The same operation as in Example 6 except that the rotational speed of
And phenothrin cap with an active ingredient concentration of 20% by weight.
A cell slurry was obtained (this composition 12).

The average particle size of the obtained microcapsules is 20 μm, and the film thickness is
0.01 μm, (average particle size / film thickness) was 2000.

Example 13 Sumidule L 1g (as above) and fenitrothi
On (0,0-dimethyl-0- (3-methyl-4-nitro
Phenyl) phosphorothioate) 160 g
Add to the rate of 40 g and stir until it becomes a uniform solution.
At room temperature, add to 350 g of an aqueous solution containing 5% by weight gum arabic
T.K. auto homomixer (see above
The same) was used and stirred for several minutes. The rotation speed is 7100 rpm
It was. Then, gently agitate for 24 hours in a 60 ° C constant temperature bath.
When the reaction is carried out, a microencapsulated product dispersion will be formed.
I started. Add pure water to this so that the total weight becomes 1000 g
Prepared, fenitrothion concentration 16% by weight, Fenvale
A capsule slurry having a rate concentration of 4% by weight was obtained (this composition
Things 13).

The average particle size of the obtained microcapsules is 10 μm, and the film thickness is
The average particle size / film thickness was 0.006 μm, which was 1667.

Comparative Example 1 Sumidule L (Same as above) to 15g, T.K.
Rotating speed of the auto homomixer (same as above) is 6500 rpm
The same operation as in Example 1 was performed except that the active ingredient concentration was increased.
10% by weight fenvalerate capsule slurry was obtained
(Comparative composition 1).

The average particle size of the obtained microcapsules is 5 μm, and the film thickness is
The average particle size / film thickness was 0.04 μm, which was 125.

Comparative Example 2 Sumidule L (Same as above) to 15g, T.K.
Rotating speed of auto homomixer (same as above) to 2150 rpm
The same operation as in Example 5 was performed except that the
10% by weight of Fenpropasulin capsule slurry
(Comparative composition 2).

The average particle size of the obtained microcapsules is 25 μm, and the film thickness is
0.333 μm, (average particle size / film thickness) was 75.

Comparative Example 3 A fenvalerate emulsion having an active ingredient concentration of 10% by weight was produced by a conventional method according to the lower formulation (Comparative Composition 3).

Fenvalerate 10 parts by weight Solpol 3005X  10 parts by weight (registered trade name of Toho Chemical; nonionic surfactant and anio
Mixture with anionic surfactant)Xylene leftover 100 parts by weight Comparative Example 4 Fenpro with an active ingredient concentration of 10% by weight was prepared according to the lower formulation.
A pasterin emulsion was prepared by a conventional method (Comparative Composition 4).

Fenpropasulin 10 parts by weight Solpol 3005X (Same as above) 10 parts by weightXylene leftover 100 parts by weight Test Example 1 Pot planted citrus (four season harvested sweet lid) was diluted 1000 times with water
Using the spray gun on the turntable
50 ml was sprayed per 5 pots. At this time, in the diluted chemical solution
0.0002% by weight specially made lino (Made by Nippon Pesticides Co., Ltd.)
It was added as a spreading agent.

The treated pot containing kanran was left in a glass greenhouse, and leaves were cut on a predetermined day and placed in a cup with a diameter of 12 cm together with 10 third-instar larvae of Spodoptera litura, and the number of dead larvae was examined 48 hours later. The test was performed 3 times, and the number of dead insects was calculated by the following formula.

The results are shown in Table 1.

Test Example 2 Female beans obtained in pots 2 weeks after seeding (2 plants per pot)
Approximately 30 heads of adult spider mites were inoculated per pot, 3 days later
Spray a 1000 times diluted solution of the drug on the turntable.
50 ml was sprayed per 5 pots using a sprayer. At this time, the drug is rare
Specially made lino in the solution Spread 0.0002% by weight (same as above)
It was added as a glue.

The treated pot was left in an amy room and the number of female mites was examined on a predetermined day.

The results are shown in Table 2.

Test Example 3 A test fenvalerate microcapsule slurry or a test fenvalerate emulsion (Comparative composition 3) diluted to a predetermined concentration was placed in a glass container having a size of 21 cm × 16 cm × 23 cm.
Into a liter, 10 medaka fishes were swam into this, and life and death were observed 48 hours later, and the half-lethal concentration as fenvalerate was determined based on the results (TLm ₄₈ (MC)).

The same operation was performed using fenvalerate drug substance instead of the fenvalerate microcapsule slurry, and the half-lethal concentration as fenvalerate was determined (TLm ₄₈
(TG). ).

TLm ₄₈ (MC) / TLm ₄₈ (TG) was calculated as the fish poison reduction rate. The results are shown in Table 3.

<Effects of the Invention> As described above, the microencapsulated agricultural insecticide of the present invention, the acaricidal composition is a pyrethroid agricultural insecticide,
The acaricide is useful because it can further reduce residual effect and fish toxicity.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kumi Takeda Kishiro-cho, Kasai City, Hyogo Prefecture Shionoyama (no address) In Sumitomo Chemical Co., Ltd. Mountain (no street number) In Sumitomo Chemical Co., Ltd. (72) Inventor Kozo Tsuji 3-98 Kasugadaka, Konohana-ku, Osaka City, Osaka Prefecture Sumitomo Chemical Co., Ltd.

Claims (1)

[Claims] 1. A microcapsule comprising a polyurea-based coating, having an average particle diameter of 80 μm or less and a film thickness of
0.3 μm or less and (average particle size / film thickness) is 2
A microencapsulated agricultural insecticidal and acaricidal composition comprising a pyrethroid insecticidal and acaricidal agent in a polyurea-based coating of 50 or more.