JPS6125681B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a weeding powder with good suspension properties. 3,4-dimethyl-2,6-dinitro-N-
(1-Ethylpropyl)aniline (hereinafter referred to as pendemethalin) is This compound is a herbicide that is highly effective in controlling weeds in field crops such as crabgrass and sagebrush. Stems and leaves of growing weeds are usually dissolved in a solvent and added with an emulsifier to make an emulsion, or finely ground with fine mineral powder, a surfactant, etc. to make a wettable powder, and then diluted with a certain amount of water. It can be applied to the ground or applied to the soil before weeds emerge. When pendemethalin is used as a wettable powder, it is sufficiently pulverized using an air flow mill or the like to enhance the herbicidal effect and to uniformly suspend the components in the spray solution.
Pendemethalin is a yellow-red crystal with a melting point of 56-58℃, and because it sublimes, it gasifies when exposed to high temperatures in summer, and once sublimated, it crystallizes on the surface of the hydrating powder particles as the temperature drops. By repeating this, grain growth and grain coalescence occur, resulting in a loss of the pulverization effect. There are also losses such as volatilization from packaging containers. Unless these points are resolved, it is difficult to say that the agricultural chemical formulation is perfect. In general, when wettable powders are diluted with water, it is necessary to maintain a stable suspension of the finely divided active ingredients, and those with reduced suspension properties may cause clogging of the spray nozzle, uneven spraying, etc. It causes a decrease in work efficiency and lack of efficacy, and has little utility as a hydrating agent. Normally, when making sublimable pesticides into wettable powders, a fine powder carrier with adsorption properties is used as an extender, and once the sublimated gas is adsorbed to the fine powder carrier, a method is used to prevent the gas from evaporating outside. I've tried using containers, but I can't seem to find a fundamental solution. In producing a hydrating powder of pendemethalin, the present inventors conducted extensive research to solve the drawbacks of formulations resulting from sublimation, and found that pendemethalin was used as a bulking agent, higher alcohol sulfate salt, and polyvinyl alcohol. The present invention has been completed based on the discovery that by uniformly blending pendemethalin with the above ingredients, it is possible to obtain a hydrating agent that does not sublimate or precipitate pendemethalin even under high temperatures in summer and has good suspension properties. It is. The hydrating agent with good suspension properties of the present invention is obtained by blending pendemethalin with an extender selected from fine mineral powder, surfactants, dispersants, etc., a sulfate ester salt of a higher alcohol, and polyvinyl alcohol. Examples of the higher alcohol of the higher alcohol sulfate ester salt used in the present invention include reduced alcohol of coconut oil, lauryl alcohol obtained from Matsukou whale oil, etc., oleyl alcohol, propylene,
Examples include primary or secondary synthetic higher alcohols made from α-olefins such as ethylene. Examples include salts of lauryl sulfate, oleyl sulfate, and 7-ethyl-2-methyl-undecane-4-ol sulfate. Examples of salts include sodium, potassium, ammonium, and organic amines. The polyvinyl alcohol used in the present invention is a polymer compound obtained by saponifying polyvinyl acetate with an alkali, acid, aqueous ammonia, or the like. There are various types depending on the degree of polymerization, saponification degree, etc., but those with low polymerization are easily compatible with water and are more effective. The ratio of higher alcohol sulfate and polyvinyl alcohol is 1 by weight for the former and 1 for the latter.
The ratio of the mixture of higher alcohol sulfate salt and polyvinyl alcohol to pendemethalin is preferably in the range of 0.2 to 0.02 by weight, while the latter is 1. If the ratio is outside the above range, sublimation of pendemethalin may be prevented. effect will be less. The fine mineral powder used in the present invention is one that is added as an extender and can be one that is widely used in agricultural chemicals. For example, it is a crushed product of 300 mesh or more of silica and alumina minerals such as clay, talc, diatomite, pyrofluorite, montmorillonite, and kaolinite. As the surfactant, alkylaryl sulfonate, polyoxyalkylene alkylaryl ether, polyoxyalkylene alkyl ether, and as dispersant, lignin sulfonate, polyvinyl alcohol, alkylnaphthalene sulfonate, etc. are used. The method for producing the wettable powder of the present invention employs a conventional method such as adding bulking agents such as fine mineral powder, surfactants, and dispersants to the active ingredients, mixing them uniformly, and then pulverizing them. . It can be produced using ordinary wettable powder equipment, and does not require any special equipment. Examples of fine pulverization methods include air flow pulverization such as a jet oomizer, and impact pulverization such as a hammer mill. It goes without saying that the hydrating agent of the present invention may further contain other nonionic or anionic surfactants, stabilizers, herbicidal efficacy enhancers, and the like.
The present invention is applicable not only to a single hydrating powder of pendemethalin, but also to a preparation in which it is mixed with other herbicides or, if necessary, fungicides, insecticides, etc. The hydrating agent of the present invention is characterized in that the sublimation of pendemethalin can be prevented by using pendemethalin in combination with a higher alcohol sulfate salt and polyvinyl alcohol within a certain range.
Higher alcohol sulfate salt alone, a combination of polyvinyl alcohol and a surfactant other than higher alcohol sulfate salt, or a combination of higher alcohol sulfate salt and other surfactant,
It is not possible to obtain a pendemesalin hydrating agent having good suspension properties at high temperatures in summer as in the present invention. Next, examples of the present invention will be described. Example 1 50 parts of pendemethalin (hereinafter shown in parts by weight), 0.5 part of sodium salt of lauryl sulfate, partially saponified low polymerized polyvinyl alcohol (polymerization degree
1000 or less, degree of saponification 86.5-89.0 mol%, Gohsenol GL-05, registered trademark of Nippon Gohsei Chemical Industry Co., Ltd.) 1.0
1 part, 43.5 parts of clay, and 5 parts of synthetic sodium silicate were uniformly mixed, and then finely pulverized using a jet oomizer. Example 2 50 parts of pendemethalin, 5 parts of sodium salt of oleyl sulfate, partially saponified polymerized polyvinyl alcohol (degree of polymerization 1500 or more, degree of saponification 86.5~
89.0 mol %, 2 parts of Gohsenol GH-17 (registered trademark of Nippon Gosei Kagaku Kogyo Co., Ltd.), 10 parts of diatomaceous powder, and 33 parts of clay were mixed uniformly, and then finely ground using a jet oomizer. Example 3 Pendemethalin 50 parts, 7-ethyl-2-methyl-undecane-4-ol sulfate sodium salt 1
3 parts, Gohsenol GL-05 (same as above),
After uniformly mixing 5 parts of diatomaceous powder and 41 parts of clay, the mixture was pulverized using a jet oomizer. The mechanism by which the sublimation of pendemethalin and precipitation of crystals are improved by the present invention has not been elucidated, but polyvinyl alcohol dissolves in the small amount of water present in the wettable powder and coats the surface of the pendemethalin particles. It is thought that this is because the sulfate ester salt of higher alcohol acts as a dissolution aid or coating aid for polyvinyl alcohol. Next, the effects of the present invention will be specifically explained using test examples. The following comparative example was prepared and used in the test. A formulation was prepared in the same manner as in Example 1 except that the ratios (parts by weight) of sodium lauryl sulfate, Gohsenol GL-05, synthetic sodium silicate, and clay in Example 1 were changed as shown in Table 1.

【table】

[Table] Comparative Example 7 A formulation was prepared in the same manner as in Example 1 except that polyoxyethylene nonyl phenyl ether was used in place of the sodium salt of lauryl sulfate in Example 1. Comparative Example 8 A formulation was prepared in the same manner as in Example 2 except that the sodium salt of butylnaphthalene sulfonic acid was used in place of the sodium salt of oleyl sulfate in Example 2. Comparative Example 9 A formulation was prepared in the same manner as in Example 1 except that polyoxyethylene sorbitan fatty acid ester was used in place of the partially saponified low-polymerized polyvinyl alcohol of Example 1. Comparative Example 10 A formulation was prepared in the same manner as in Example 3 except that Gohsenol GL-05 in Example 3 was replaced with calcium salt of nignisulfonic acid. Test Example 1 (Heat resistance test) 100g of each sample prepared according to Examples and Comparative Examples
was placed in a 500 c.c. glass bottle, left in a 50℃ thermostat for 10 days, allowed to cool to room temperature, and before treatment, a physical property test was conducted in accordance with the Official Pesticide Testing Method (Ministry of Agriculture, Forestry and Fisheries) to determine suspension and powder properties. The degree (wet method) was determined. The results are shown in Table 2.

【table】

[Table] From the above test results, it can be seen that according to the present invention, good suspension properties and fineness are maintained even after treatment without being affected by the sublimation of the active ingredients. Test Example 2 (Herbicidal effect test) Seeds of Japanese wildflower, crabgrass, Japanese knotweed, pigweed, and blueberry were placed in 0.5 cm each in a polyethylene container (capacity 50 x 40 x 20 cm) with an internal area of 2000 cm ² filled with field soil. After sowing the seeds to a deep depth, they were covered and lightly suppressed. Next, each sample prepared according to Examples 1 to 3 and Comparative Examples 1 to 10, which had been left in a 50°C incubator for 10 days, was diluted with 100 ml of water to give 10 mg of the active ingredient, and after 30 minutes of dilution, 20 ml of the supernatant liquid per container (corresponding to a treatment of 10 g of active ingredient at a water volume of 100 per 10 A) was uniformly spread over the upper soil surface layer.
The herbicidal effect was investigated 20 days after spraying. The results are shown in Table 3 based on the average value of three replicates according to the following criteria.
Shown below.

【table】

【table】

[Table] In the comparative example, which was left in a thermostat at 50°C for 10 days, the herbicidal effect decreased as the suspension and powderiness decreased, but in the example, the herbicidal effect did not decrease, proving the effectiveness of the present invention. Ru.

Claims (1)

[Claims] 1 3,4-dimethyl-2,6-dinitro-N-
(1-Ethylpropyl)aniline, an extender, a higher alcohol sulfate salt and polyvinyl alcohol are added, and the mixing ratio of the higher alcohol sulfate salt and polyvinyl alcohol is in the range of 1 to 10 for the latter by weight. , and a mixture of higher alcohol sulfate salt and polyvinyl alcohol, and 3,4-dimethyl-2,6-dinitro-N
- (1-Ethylpropyl)aniline A wettable powder for weeding with good suspension properties, characterized in that the mixing ratio of the former with 0.02 to 0.2 is in the range of 1 with the latter.