JPS6332046B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides O,O-dimethyl S-[1,2-
Di-(ethoxycarbonyl)ethyl] phosphorodithioate, O,O-dimethyl O-(4-dianophenyl) phosphorothioate, O,O
-dimethyl S-[α-(ethoxycarbonyl)benzyl] phosphorodithioate, O,O-dimethyl O-(2-isopropyl-4-methyl-
6-pyrimidinyl) One or more selected from phosphorothioate, 1 to 50% by weight, polyvinyl alcohol or gum arabic, 2 to 10% by weight, an appropriate amount of thickener, and residual water. This is an oil-in-water emulsion insecticidal composition. Among the conventional pesticide formulations that are sprayed in liquid form, emulsions generally consist of a pesticide active ingredient, a synthetic surfactant, and a large amount of organic solvent. They often have drawbacks such as toxicity and irritation to plants and phytotoxicity to crops. On the other hand, there are powdered wettable powders that do not use organic solvents, but when preparing the spray liquid,
The fine powder scatters and is inconvenient to handle, and the high concentration and small amount of air spraying (300 ml per 10 ares)
ml or less) cannot be denied. For the above reasons, pesticide suspension compositions and aqueous emulsions in which hydrophobic pesticide ingredients are suspended and dispersed in fine particles using water as a base instead of organic solvents, powder carriers, etc. have been studied. . Since this type of composition is handled as a liquid, it does not generate dust when preparing the spray solution, and it is easy to handle quantitatively like a conventional liquid formulation. There are fewer problems with chemical damage to crops. However, in the suspension pesticide compositions that have been proposed so far, the hydrophobic pesticide active ingredient, which is the active ingredient, is mainly in solid form (Japanese Patent Application Laid-open Nos. 49-126635 and 50-76236). , JP-A-52-148625, U.S. Patent No. 4,071,617, etc.), oil-in-water type oil-in-water products using oily base materials are generally difficult to stabilize their physical properties over a long period of time, and are not suitable for practical use. has not been standardized. On the other hand, as an oil-in-water type agricultural chemical composition,
No. 20520, JP-A-49-54547, JP-A-52-122628
There are aqueous emulsions such as those published in various publications, but these are solubilized types that use a large amount of general-purpose synthetic surfactants to reduce the particle size of the active ingredient to 0.1 μm or less, and have a large amount of interfacial High costs due to the use of activators;
Shortcomings such as toxicity remain unresolved. The present inventors have developed O,O-dimethyl having a water solubility of 1000 ppm or less at 10°C as a liquid insecticidal ingredient.
S-[1,2-di-(ethoxycarbonyl)ethyl] phosphorodithioate (hereinafter referred to as compound (1). Water solubility at 10°C is 145 ppm), O,O-dimethyl O-(4-cyanophenyl) phos Holothioate (hereinafter referred to as compound (2); water solubility at 10°C is 28 ppm), O,O-dimethyl S-[α-
(Ethoxycarbonyl)benzyl] phosphorodithioate (hereinafter referred to as compound (3). Water solubility at 10°C is 4 ppm), O,O-dimethyl O-(2
-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate (hereinafter referred to as compound (4). Water solubility at 10°C is 50 ppm), organic solvent, general-purpose synthesis as in the conventional composition described above. Surfactants, such as higher alcohol sulfate ester salts, higher alcohol sulfonates, alkyl sulfonates, arylsulfonates, alkylaryl sulfonates and their formalin condensates, fatty acid ester compounds, polyoxyethylene alkyl ethers , polyoxyethylene aryl ether, polyoxyethylene alkylaryl ether, polyoxyethylene phenylphenol derivatives, polyoxyethylene sorbitan alkylate, etc., and its chemical and physical properties are stable and effective for a long period of time. In order to obtain oil-in-water emulsion insecticidal compositions that are as good as conventional formulations, various studies have been conducted on methods of using water-soluble polymers as emulsion aids. As a result, as emulsion aids for these compounds,
It has been found that polyvinyl alcohol or gum arabic is most suitable, and the present invention has been completed. That is, the above-mentioned organic phosphorus compound as a liquid insecticidal ingredient is mechanically dispersed and emulsified as fine particles in an aqueous solution of polyvinyl alcohol or gum arabic, and the fine particles are stabilized by adding an appropriate thickener. We have succeeded in obtaining an insecticidal composition that meets the above objectives at a low cost by a simple operation such as oxidation. Experimental Example 1 is shown below as proof that gum arabic and polyvinyl alcohol are excellent emulsion aids among water-soluble polymers. Experimental example 1 Albumin, cellulose sulfate derivative, sodium alginate, carrageenan, polyvinylpyrrolidone, carboxymethyl cellulose, sodium lignin sulfonate, gelatin, gum arabic, and Gohsenol GL-05 (Nippon Gosei Kagaku Kogyo Co., Ltd. trade name polyvinyl alcohol, degree of polymerization 1000 or less) , 2% by weight aqueous solution with saponification degree of 86.5 to 89 mol%)
Add 20g of the five types of liquid organophosphorus insecticidal ingredients listed in Table 1 to each 180g, and use a TK homomixer (trade name of Tokushu Kika Kogyo Co., Ltd.) to form oil droplets of the insecticidal ingredients with a particle diameter of 1 to 100g. After being dispersed to a size of 100μ, each was sealed in a sealed glass container and stored in a constant temperature dryer at 60°C, and the dispersion stability was observed after one day of storage. The results are shown in Table 1. [Table] As shown in the table above, it was confirmed that gum arabic and polyvinyl alcohol are excellent emulsion aids. Further, Experimental Example 2 is shown below as proof that a liquid organic phosphorus compound having a water solubility at 10°C of 1000 ppm or less is suitable as an active ingredient to be included in the present composition. Experimental Example 2 Compound (1), Compound (2), Compound (3) and Compound (4)
In addition, 2,2-dichlorovinyl O,O-dimethyl phosphate (water solubility at 10°C is about 10,000 ppm) and O,O-diethyl ( 20 parts by weight of 3-cyanophenylmethyl) phosphonate (water solubility at 10°C is about 6000 ppm) were added separately to 80 parts by weight of Gohsenol GL-052 weight% aqueous solution and to 80 weight parts of gum arabic 2 weight% aqueous solution. After dispersing the insecticidal ingredient oil droplets with a TK homomixer (trade name of Tokushu Kika Kogyo Co., Ltd.) so that the particle size is 1 to 100μ, each was sealed in an airtight glass container and heated at 50℃.
The dispersion stability was observed after one day of storage. The results are shown in Table 2. [Table] As shown in the table above, the water solubility at 10℃ is
It was confirmed that the liquid organophosphorus insecticidal component with a concentration of 1000 ppm or less clearly showed a stable emulsion state and was suitable as an active ingredient to be included in the present composition. To briefly describe the manufacturing process of this composition, first, a predetermined amount of a liquid organophosphorus insecticidal ingredient with a water solubility of 1000 ppm or less at 10°C is added to a 2-20% by weight aqueous solution of polyvinyl alcohol or gum arabic. In addition, the mixture is dispersed and emulsified using an ordinary stirrer, such as a TK homomixer (trade name of Tokushu Kika Kogyo Co., Ltd.) or a Shinagawa multipurpose mixer (trade name of Sanei Seisakusho Co., Ltd.). In addition, the size of the emulsified insecticidal ingredient oil particles varies from approximately 1 μm to approximately 1 μm depending on the stirring intensity and the amount of polyvinyl alcohol or gum arabic added.
Adjustment is possible within a range of about 200μ. Note that the particle size is checked using a microscope. Finally, in order to prevent sedimentation of suspended particles and increase dispersion stability, an aqueous solution of a thickener is mixed in an appropriate proportion to obtain an emulsified insecticidal composition that is stable for a long time. In the present invention, polyvinyl alcohol has a degree of polymerization of 1500 or less and a degree of saponification of 70 to 90 mol%.
For example, Gohsenol GL
-05 (trade name of Nippon Gosei Kagaku Kogyo Co., Ltd., degree of polymerization 1000 or less, degree of saponification 86.5 to 89 mol%) is used. Examples of thickeners include gum tragacanth, guar gum, sodium alginate, sodium carboxymethyl cellulose, sodium carboxymethyl starch, hydroxyethyl cellulose, methyl cellulose, polyacrylic acid and its derivatives, commercially available Agrisol FL-100F (trade name of Kao Atlas Co., Ltd.), Primal ASE−
60 (trade name of Nippon Acrylic Co., Ltd.), Rheozik 250H (trade name of Nippon Pure Chemical Co., Ltd.), Carbopol (trade name of BF Gutsudoritsuchi Chemical Company), etc. can be used. The amount of these thickeners added ranges from 0.1 to 20% by weight,
The optimum amount to be added differs depending on each thickener. The oil-in-water emulsion insecticidal composition of the present invention does not use any organic solvents, so there is no need to worry about flammability, bad odor from solvents, toxicity to humans, livestock, and small animals, irritation, and chemical damage to crops. It is also convenient in that it has good water dilutability when preparing and is easy to handle quantitatively like conventional liquid preparations. Next, examples of the present invention will be shown below. The examples are illustrative and the invention is not limited thereto. Examples 1 to 4 Compound (1), Compound (2), Compound (3) and Compound (4)
10g each separately of Gohsenol GL-05
(Product name of Nippon Gosei Kagaku Kogyo Co., Ltd., polyvinyl alcohol, degree of polymerization 1000 or less, degree of saponification 86.5-89.0
Add 40 g of a 10 wt% aqueous solution of
The mixture was stirred for 5 minutes at a rotation speed of 5000 rpm using a TK homomixer (trade name of Tokushu Kika Kogyo Co., Ltd.). Further, at room temperature, 50 g of a neutralized 20% by weight aqueous solution of Agrisol FL100F (trade name of Kao Atlas Co., Ltd.) is added and mixed with gentle stirring for several minutes, resulting in an oil-in-water emulsion with an organic component concentration of 10% by weight. 100 g of formulation was obtained. The particle size width is
It was 1μ to 40μ. The number of the example corresponds to the number of the compound contained in the composition obtained by the example. Examples 5 to 8 A predetermined amount of the insecticidal compound in Table 3 was added to an aqueous solution containing Gohsenol GL-05 or gum arabic listed in Table 3, and stirred at room temperature with a TK homomixer at a rotation speed of 5000 rpm for 5 minutes. did. Furthermore, when an aqueous solution of the thickener in Table 3 is added and mixed at room temperature, each oil-in-water emulsion preparation
100g was obtained. [Table] [Table] Example 10 An oil-in-water emulsion formulation containing 10% by weight of compound (4) was prepared by carrying out exactly the same operation as in Example 8 except that the rotation speed of the TK homomixer was changed to 2500 rpm.
100g was obtained. The particle diameter range was 1μ to 150μ. Example 11 The stability of the composition of the present invention was tested using the compositions obtained in Example 2 and Example 4 (hereinafter referred to as Composition 2 and Composition 4, respectively).
The results are shown in Table 4. [Table] [Table] * Values based on content analysis values during adjustment Example 12 Each oil-in-water emulsion formulation with an active ingredient concentration of 10% by weight obtained in Examples 1, 2, 3, and 4 4 Potted eggplant (variety:
After spraying on a turntable (Senryo No. 2) at a rate of 50 ml/3 pots, after air drying, the fully expanded leaves were cut, placed in a polycup, and a group of 10 adult Nijiyuyahoshi lady beetles were released, and after 2 days each. The mortality rate was determined. As control formulations, four 10% by weight emulsions containing the same active ingredients as these oil-in-water emulsions (hereinafter referred to as control formulations 1, 2, 3 and 4) were used and treated in the same way. I did this. *The formulations of control preparations 1 to 4 are as follows. Active ingredient 10w/w% Solpol 3005X 10 (Mixture of nonionic surfactant and anionic surfactant, Toho Chemical Co., Ltd. trade name) Xylene Remaining 100 [Table] As shown in the table above, the composition of the present invention It was confirmed that the product exhibited the same excellent efficacy compared to the control formulation. Example 13 Three compositions 2, 3, and 4 and three control preparations 2, 3, and 4 at predetermined concentrations were placed on a turntable on tillering stage rice plants (1/ Sprayed at a rate of 30ml/2 pots (planted in 10,000a Wagner pots). Five days after spraying, the rice plants were disassembled and the survival of the ingested larvae was investigated. [Table] [Table] As shown in the above table, it was confirmed that the composition of the present invention exhibited excellent efficacy equivalent to that of the control formulation. Example 14 Regarding the mucous membrane irritation of the composition of the present invention, the composition obtained in Example 5 (hereinafter referred to as composition 5) was used, and the composition according to the EPA guidelines [Federal Register,
43, 37359-37360 (1978)] for eye irritation in rabbits. At the same time, a 40% by weight emulsion containing the same active ingredients as Composition 5 (hereinafter referred to as Control Formulation 5) was also subjected to a similar test for comparative study. The experimental results are shown in Table 7, and the stimulus response intensity and maximum total score of stimulus intensity in the table are values obtained according to the stimulus response criteria in Table 8. *The formulation of the 40% emulsion is as follows. w/w% Compound (1) 40 Solpol L550 11 (Mixture of nonionic surfactant and anionic surfactant, Toho Chemical Co., Ltd. trade name) Solpol H770 1 (same as above) Epichlorohydrin 1 Xylene Remaining 100 [ Table] Comparing the intensity of irritation response and the maximum total score of stimulation intensity between the present composition and the control preparation, it was confirmed that the degree of irritation was clearly lower with the present composition than with the control preparation. Table 8 Judgment criteria for reactions in eye irritation tests (from EPA guidelines) Corneal Intensity of reaction (A) No abnormality in the strength of opacity...0 Opaqueness sufficient to observe the details of the iris...1 Corneal Opacification, opacity that makes it difficult to observe the details of the iris...2 Opalescence, opacity that makes it difficult to see the details of the iris and the diameter of the pupil can be barely observed...3 Strong opacification, inability to see through, opacity that makes the iris unrecognizable
…4 (B) No abnormality in the width of the turbidity …0 Opaqueness of 1/4 or less …1 Opacity of more than 1/4 and less than 1/2 …2 Opaqueness of more than 1/2 and less than 3/4 …3 3 Cloudiness of /4 or more...4 Score = A x B x 5 Maximum score 80 Iris No abnormality of reaction intensity found...0 Obvious congestion, edema, hyperemia of the corneal periphery, photoreaction present...1 No photoreaction, Bleeding, macroscopic tissue degeneration
…2 Score = Rating x 5 Maximum score 10 Conjunctiva (A) Flushing No abnormalities found …0 Obvious hyperemia in some blood vessels …1 The whole becomes deep red, making it impossible to identify individual blood vessels
…2 The entire eyelid is dark red …3 (B) Edema No abnormality observed …0 Very slight edema …1 Obvious edema that causes part of the eyelid to eclipse …2 Edema that closes about half of the eyelid …3 Edema that closes more than half of the eyelid … 4 (C) Eye discharge: No abnormalities in the intensity of the reaction were observed (including a very small amount of secretion in the nasal canthus)...0 A very small amount of secretion was observed in the eyelids...1 A small amount was also observed in the hair near the eyelids... 2 Appears in a wide range of hair near the eyelids...3 Score = (A+B+C) x 2 Maximum score 20

Claims (1)

[Claims] 1 O,O-dimethyl S-[1,2-di-ethoxycarbonyl)ethyl] phosphorodithioate, O,O-dimethyl O-(4-cyanophenyl) phosphorothioate, O, O-dimethyl S-[α-(ethoxycarbonyl)benzyl]
Phosphorodithioate, O,O-dimethyl
1 to 50% by weight of one or more selected from O-(2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate, 2 to 10% by weight of polyvinyl alcohol or gum arabic, and an appropriate amount of An oil-in-water emulsion insecticidal composition, characterized in that it consists essentially of a thickener and residual water.