JPH05139916A - Aqueous suspended herbicidal formulation composition for farmland - Google Patents

Abstract

PURPOSE:To obtain the subject composition by mixing methyl-O-methoxy- carbonylmethyl-5-(2,4-dichloro-3-methylphenoxy)-2-nitrobenzohydroximate which is a herbicide with a specific dispersing agent or a wetting agent. CONSTITUTION:An aqueous suspended herbicidal formulation composition for farmland is obtained by mixing methyl-O-methoxy-carbonylmethyl-5-(2,4- dichloro-3-methylphenoxy)-2-nitrobenzohydroximate which is a herbicide with an ingredient selected from sodium salt of di-2-ethylhexyl sulfosucciniate, ethoxylated styryl phenyl ether, polyoxyalkylene glycols, ethoxylated nonyl phenyl ether and ethoxylated octyl phenyl ether as a dispersing agent or a wetting agent, pulverizing the resultant mixture by a wet pulverizing method and adding water to the prepared powder. A flowable agent containing an extremely fine particulate herbicidal compound containing 250wt.% particles having <=0.5mum particle diameter is obtained by this method. Herbicidal effects are remarkably improved and comparable to those of emulsions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a herbicidal composition in the form of an aqueous suspension which has a remarkably enhanced herbicidal effect.

[0002]

[Background Art and Problems] Herbicidal active ingredients that are sparingly soluble in water are emulsions that are uniformly dissolved in an organic solvent such as xylene and toluene together with a surfactant, or active ingredients that are in a solid state with water as a continuous phase. It can take the form of an aqueous suspension formulation (hereinafter referred to as a flowable agent) in which is dispersed, but since the emulsion uses an organic solvent, the storage / transportation of the product, environmental safety, and safety for workers In addition, there are many problems in terms of occurrence of chemical damage to crops, and it cannot be said that the dosage form is always preferable, and formulation with a flowable agent advantageous in these points is desired. However, the flowable agent has a problem that the herbicidal effect is generally inferior to that of the emulsion.

Diphenyl ether type herbicide, methyl O
-Methoxy-carbonylmethyl-5- (2,4-dichloro-3-methylphenoxy) -2-nitrobenzohydroxymate (described in JP-A-63-215605, hereinafter referred to as compound 1) is Water solubility is 0.
As low as 22 ppm (25 ° C), it is desirable to formulate it as a flowable agent. However, when formulated as a flowable agent, no phytotoxicity to crops occurs at all, or even if it occurs, it is extremely small, the herbicidal effect on weeds is inferior to that of emulsions, and an effect equivalent to that of emulsions is expected. In that case, there is a problem that the amount of the active ingredient to be dropped must be increased.

[0004]

Means for Solving the Problems As a result of intensive studies aimed at creating a flowable agent of Compound 1 having a herbicidal effect equivalent to that of an emulsion, the present inventors have determined that Compound 1 and a specific dispersant or wetting agent are combined. It has been found that fine particles can be easily formed by mixing and pulverizing by a usual wet pulverizing method. The particle size of the herbicide in the composition contains 50% by weight or more of particles of Compound 1 having a particle size of 0.5 μm or less, which cannot be achieved by the conventional formulation. Moreover, if this flowable agent is used, no phytotoxicity occurs at all, or even if it occurs, the herbicidal effect is almost the same as that of the emulsion although it is extremely minute, and the dosage is 1/2 to 4 minutes of the conventional flowable. The inventors have found that it can be reduced to 1, and completed the present invention.

According to the present invention, (a) a herbicide effective substance, methyl O-methoxy-carbonylmethyl-5- (2,4)
-Dichloro-3-methylphenoxy) -2-nitrobenzohydroxymate, (b) sulfosuccinic acid di-2-ethylhexyl ester sodium salt, ethoxylated styryl phenyl ether, polyoxyalkylene glycol, ethoxylated nonyl phenyl ether, and ethoxyl An aqueous suspension herbicidal preparation comprising one or more dispersants or wetting agents selected from the group consisting of modified octyl phenyl ether, and (c) water.

That is, according to the present invention, when compound 1 is wet pulverized in the presence of the above-mentioned selected wetting agent or dispersant, 50% by weight or more of particles having a particle diameter of 0.5 μm or less are obtained. And a flowable agent with which the herbicidal effect is remarkably enhanced. More specifically, the flowable agent of the present invention does not cause phytotoxicity to crops, specifically, wheat, rice, soybean, corn, etc., but weeds, specifically, Stellaria frugiperda, F. communis, chickweed, Astragalus chinensis, Pleurotus chinensis, Yaemgra. , Wild Violet, Oroshigogaku, Chamomile, Chamomile, Poppy, Ezoglythrum, Otsumegusa, Minagusa, Nominotsuchi, Shiratamaso, Ezosuboshiro, Forget-me-nots, Shiroza, Michiyanagi, Sobagoldacon, etc. Shows herbicidal effect.

The content of the compound 1 used in the present invention is 1
The range is from 60 to 60% by weight, preferably from 10 to 40% by weight. The dispersant or wetting agent used in the present invention is sulfosuccinic acid di-2-ethylhexyl ester sodium salt,
It is selected from the group consisting of ethoxylated styryl phenyl ethers, polyoxyalkylene glycols, ethoxylated nonyl phenyl ethers and ethoxylated octyl phenyl ethers. It is difficult to prepare an extremely finely divided suspension composition in which Compound 1 has a particle diameter of 0.5 μm or less with a conventionally known dispersant other than these. These dispersants or wetting agents may be used alone or in combination of two or more, and the amount thereof is 0.1% by weight or more, preferably 0.5 to 10% by weight, in the dispersion liquid of Compound 1. Is.

Preferred dispersing or wetting agents include:
Sulfo-succinic acid di-2-ethylhexyl ester sodium salt as an anionic surfactant; Ethoxylated styryl phenyl ether containing 10 to 40 EO (ethylene oxide) units as a nonionic surfactant;
Polyoxyalkylene glycol having an average molecular weight of 2000 to 9000 and an ethylene oxide weight% in all molecules of 30 to 80; an ethoxylated nonyl phenyl ether containing 8 to 14 EO units; 8 to 14 EO units. Examples include ethoxylated octyl phenyl ether and the like.

In preparing the composition of the present invention, a water-soluble thickener, a defoaming agent, an antifreezing agent, an anti-decomposition agent, an anti-agglomeration agent and the like are appropriately added for the purpose of improving the formulation stability of the composition. can do. As the water-soluble thickener, any of natural, semi-synthetic and synthetic water-soluble thickeners can be used, and specifically, xanthan gum, guar gum, cellulose, methylcellulose, carboxymethylcellulose, polyacrylate, polyvinylpyrrolidone, etc. As. The water-soluble thickener is contained in the composition in an amount of 0.01 to 3% by weight.
It is preferably blended in an amount of 0.05 to 3% by weight. Defoamer
It is preferable to add up to about 2% by weight in order to suppress foaming during formulation. The defoaming agent is not particularly limited, and any of them can be used, for example, polypropylene glycol,
Specific examples include silicone oil. The antifreezing agent is preferably added in an amount of about 5 to 15% by weight in order to prevent freezing during storage.

The flowable agent of the present invention is produced by wet-milling a mixture of (a) to (c) together with a rigid medium. Rigid media usually have a particle size of 0.1-3μ
If using m, compound 1 will be 0.5 μm in a shorter time.
The particles are made into the following. As the material of the medium, glass, alumina, zirconia, meno and the like are used, but glass is preferable. As a device for stirring and finely pulverizing the mixture of (a) to (c) using the medium, generally known devices such as a sand mill, a sand grinder and a dyno mill may be used, and both vertical and horizontal types can be used. However, if a dyno mill is used, fine particles can be formed in a shorter time than a sand mill or a sand grinder. The temperature for crushing is preferably 5 to 30 ° C. If it exceeds 30 ° C., it becomes difficult to form fine particles, which is not preferable. Therefore, at the time of stirring, it is desirable to cool by a method suitable for each device. The mixing ratio of the medium and the compound 1 in the pulverization is in the range of 50/50 to 80/20 by volume, preferably 60.
/ 40 to 70/30. The flowable agent thus obtained has no phytotoxicity to crops as compared with the flowable agent prepared by the conventional method, and does not occur at all, or even if it occurs, it is extremely minute but the herbicidal effect is remarkably improved. It is extremely advantageous as a herbicide formulation.

[0011]

EFFECTS OF THE INVENTION According to the present invention, it is possible to produce a flowable agent containing Compound 1 in which 50% by weight or more of particles having a particle diameter of 0.5 μm or less are extremely finely divided. And, compared to the flowable agent produced by the conventional method, this flowable agent did not change the phytotoxicity to crops and remained unchanged, and the herbicidal effect was dramatically improved, and was almost equal to that of the emulsion.

[0012]

The present invention will be described in more detail with reference to the following examples. In addition, the particle size of the herbicide in the composition was measured by a microtrack particle size distribution analyzer Model 7995-10 SPA (LEEDS & NORTHRUPINSTRU) of the Franhofer diffraction type of the laser light forward scattered light and the side scattered light intensity analysis of the halogen light source.
MENTS) was used.

Example 1 (Flutable of the present invention) 30.0 g of Compound 1 and polyoxyethylene tristyryl phenyl ether (29 EO units) in a 0.15 L grinding container filled with 120 ml of glass beads having a diameter of 0.1 mm 1 .5
g, polyoxyalkylene glycol (average molecular weight 29
00, EO addition amount 34% by weight) 0.5 g, sulfosuccinic acid di-2-ethylhexyl ester sodium salt 2.0
g, silicone defoaming agent 0.1 g water 40.9 g were added, and the mixture was crushed in a Dynomill KDL-Special (manufactured by WAB) at a disk rotation speed of 2500 rpm for 120 minutes. The temperature in the container was cooled with cooling water and kept at 25 ° C or lower. After crushing for a predetermined period of time, it was separated from the glass beads by vacuum filtration to obtain 37.5 g of a suspension composition. 10 g of 0.5% welan gum in this suspension composition
And 2.5 g of propylene glycol were added and slowly stirred (50 rpm) with a lab stirrer until uniform.
Then, 50 g of a flowable agent containing Compound 1 as an active ingredient was obtained. As shown in Table 1, this flowable agent is 0.5 μ
Particles with a particle size of less than or equal to m had a particle size distribution of 85%.

Comparative Example 1 (Conventional flowable) Glass beads 1 having a diameter of 0.1 mm
In a 0.15 L grinding container filled with 20 ml, 30.0 g of Compound 1, 1.5 g of Na salt of β-naphthalenesulfonic acid formalin condensate, polyoxyethylene sorbitan monolaurate (20 EO units; trade name Tween 20) 1 0.0 g, silicone antifoaming agent
0.1g water 42.4g was added and Dynomill KDL
-250 rpm in the special (made by WAB)
Milled for 120 minutes at 0 rpm. The temperature in the container was cooled with cooling water and kept at 25 ° C or lower. After crushing for a predetermined time, it is separated from the glass beads by vacuum filtration,
37.5 g of a suspension composition was obtained. To this suspension composition, 10 g of 0.5% welan gum and 2.5 g of propylene glycol were added, and the mixture was slowly stirred (50 rpm) with a lab stirrer until uniform, and 50 g of a flowable agent containing Compound 1 as an active ingredient was added. Obtained. This flowable agent showed a particle size distribution as shown in Table 1.

[0015]

[Table 1]

Comparative Example 2 (Emulsion) 5 g of Compound 1, 5 g of calcium dodecylbenzenesulfonate, 5 g of ethoxylated tristyryl phenyl ether containing 12 EO units, 25 g of cyclohexanone and 60 g of SOLVEESO 200 (manufactured by ESSO) at room temperature. The mixture was stirred until a uniform solution was obtained, and 100 g of an emulsion containing Compound 1 as an active ingredient was obtained.

Test Example Using the flowable agent of Compound 1 obtained in Example 1, the flowable agent of Compound 1 obtained in Comparative Example 1, and the emulsion of Compound 1 obtained in Comparative Example 2, a biological test was conducted by the following method. (Test method) A square pot of 30 cm x 30 cm x 9 cm (depth) was filled with upland field soil, and wheat seeds and weed seeds shown in Table 2 were sown in fixed amounts and covered with 1 cm thick soil for 40 days. It was cultivated at an appropriate temperature and humidity. The chemical treatment was carried out by diluting Example 1, Comparative Example 1 and Comparative Example 2 with water so that the respective amounts of the active ingredients shown in Table 2 were obtained, and 4.5 ml per section was uniformly sprayed on the foliage of the plant. did. On the 45th day after the chemical treatment, the herbicidal effect on each weed and the degree of phytotoxicity to each crop were determined according to the following evaluation criteria by comparison with the non-treatment, and the results are shown in Table 2.

Evaluation Criteria Herbicidal effect; 0: no action to 100: complete death; chemical damage; 0: harmless to 100: complete death

[0019]

[Table 2]

Claims (1)

[Claims] (1) Methyl O as a herbicide active substance
-Methoxy-carbonylmethyl-5- (2,4-dichloro-3-methylphenoxy) -2-nitrobenzohydroxymate, (b) sulfosuccinic acid di-2-ethylhexyl ester sodium salt, ethoxylated styryl phenyl ether, poly Field use characterized by containing (c) water, one or more dispersants or wetting agents selected from the group consisting of oxyalkylene glycol, ethoxylated nonylphenyl ether, and ethoxylated octylphenyl ether Aqueous suspension herbicidal composition.