JPS6229401B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] This invention relates to an insecticide wettable powder containing S-methyl-N-[(methylcarbamoyl)oxy]thioacetimidate (hereinafter sometimes abbreviated as methomyl) as an active ingredient. be. [Prior art] Methomyl has strong insecticidal power, and is therefore a powerful and fast-acting carbamate insecticide that can be used against a wide range of pests that parasitize and cause harm to agricultural and horticultural crops such as vegetable, tea, tobacco, and rice. It is widely used as Since methomyl has the property of being soluble in water, it is often mixed with a solid diluent and used as a wettable powder. It is common to use a solid diluent (carrier). By the way, methomyl is a compound that is designated as a deleterious substance and has low dermal toxicity, but very strong oral inhalation toxicity.To prevent poisoning among farm workers, it is necessary to provide formulations that do not generate dust when preparing the spray solution. . Generally, powder formulations are mixed with a small amount of non-volatile liquid such as liquid paraffin, polyhydric alcohols, machine oil, etc. to prevent dust generation and drifting of the fine powder. . Regarding methomyl wettable powders, formulations are known that use ethylene glycol, diethylene glycol, polyethylene glycol, and/or water to prevent dust generation (Japanese Patent Application Laid-open No. 81620/1983). However, such conventional methomyl hydrating agents do not have very remarkable dust generation prevention properties, and
Due to the lack of fluidity, under storage conditions, especially at high temperatures, the powder will show a significant solidification phenomenon, which not only reduces the commercial value, but also makes it difficult to dissolve in water when preparing the spray solution, making it difficult to work. was difficult. Furthermore, the weather conditions (temperature,
The solidification properties of the wettable powder fluctuate due to the influence of humidity (humidity, etc.), and the wettable powder tends to be classified when it is put into the storage tank from the mixer, which tends to cause variations in the active ingredients. [Purpose of the Invention] This invention is intended to improve the above-mentioned conventional problems. By incorporating glycerin or polypropylene glycol as a dust prevention agent, dust prevention, fluidity, and solidification prevention are achieved. The purpose of the present invention is to provide an insecticide wettable powder that has excellent properties, is less affected by weather conditions during production, and has less variation in active ingredients. [Structure of the Invention] The present invention is a composition comprising S-methyl-N-[(methylcarbamoyl)oxy]thioacetimidate and a water-soluble carrier selected from glycerin and polypropylene glycol having an average molecular weight of 400 to 1200. This is an insecticide wettable powder characterized by containing 1% by weight or more of one or more types of compounds. Methomyl contained as an active ingredient in the present invention is a compound represented by the following formula, and is 20 to 80% by weight, preferably 40 to 60% by weight in the composition of the present invention.
It is blended. As the water-soluble carrier, water-soluble solid diluents commonly used for wettable powders, such as ammonium sulfate, sodium sulfate, urea, etc., can be used, and preferably 30 to 70% by weight of the composition of the present invention.
It is blended in an amount of 30 to 50% by weight. Glycerin and polypropylene glycol are used as dust prevention agents, and can be used singly or in combination of two or more, and polypropylene glycol having an average molecular weight of 400 to 1,200 is used. The reason why the average molecular weight of polypropylene glycol is limited to 400 to 1,200 is that outside this range, it lacks anti-dusting properties or anti-caking properties. Glycerin and/or polypropylene glycol is blended in the composition of the present invention in an amount of 1% by weight or more, but if it is less than 1% by weight, it lacks dust prevention properties.
Moreover, if it exceeds 5% by weight, the fluidity of the powder will be inhibited and it will be economically impractical, so it is desirable to set it to 1 to 5% by weight. In addition to the above-mentioned components, the insecticide wettable powder of the present invention can also contain other components such as oil-absorbing mineral fine powder, coloring agents, and surfactants. Examples of the oil-absorbing mineral fine powder include zeolite and silica earth. As the surfactant, those commonly used for wettable powders such as alkylbenzene sulfonate and salt of β-naphthalene sulfonic acid formalin condensate can be used. The preferred blending ratio is 3-5% by weight of oil-absorbing mineral fine powder, 0.01-0.1% by weight of colorant, and 0.1% by weight of surfactant.
~1% by weight. The insecticide wettable powder of the present invention is a mixture of the above components, and is preferably produced by mixing a water-soluble carrier and a dust prevention agent, then mixing methomyl, and mixing the other components last. However, they may be mixed in other orders. The insecticide wettable powder obtained as described above is dissolved in water to prepare a spraying liquid, which is then sprayed on fields and the like to be used as an insecticide. [Effects of the Invention] According to the present invention, at least 1% by weight of one or more compounds selected from glycerin and polypropylene glycol having an average molecular weight of 400 to 1200 is blended into the composition containing methomyl and a water-soluble carrier. It has excellent dust prevention properties, fluidity, and solidification prevention properties, is less affected by weather conditions such as temperature and humidity during formulation, and has other effects such as less variation in active ingredients. [Embodiments of the Invention] Next, embodiments of the present invention will be described. In each example, parts indicate parts by weight. (Example 1) Add 42 parts of pre-pulverized ammonium sulfate to a Nauta mixer, and add 3 parts of glycerin while stirring.
After mixing for 15 minutes, add methomyl drug substance.
Add 52 parts and continue mixing for 10 minutes, and finally add 3 parts of zeolite and mix for 5 minutes to homogenize to obtain a product. (Example 2) Add 42 parts of pre-pulverized ammonium sulfate to a ribbon mixer, and adjust the average molecular weight while stirring.
Drop 3 parts of 400 polypropylene glycol
After mixing for 15 minutes, add 52 parts of methomyl raw material.
Continue mixing for 10 minutes, and finally add 3 parts of zeolite and mix for 5 minutes to homogenize to form a product. (Example 3) Put 41 parts of sodium sulfate into a Nauta mixer,
While stirring, drop 4 parts of polypropylene glycol with an average molecular weight of 1200 and mix for 15 minutes. Add 52 parts of methomyl and continue mixing for 10 minutes. Finally, add 3 parts of zeolite and mix for 5 minutes to homogenize. do. Next, the effects of the present invention will be specifically explained using test examples. The test method in each test example was as described below. (1) Dust generation test method: Place 20 g of the sample in a 1-volume mayonnaise bottle, shake vigorously up and down, let it stand, and observe with the naked eye the time until most of the suspended particles have settled, according to the following criteria. I made a judgment. Time required for settling Judgment Less than 15 seconds 〇 15 seconds to less than 30 seconds △ More than 30 seconds × (2) Solidification test method After placing 100 g of sample in an aluminum bag and sealing it, apply a pressure equivalent to approximately 25 g/cm ² Add, 40℃, 50
After storing it in a thermostat at 60°C for 24 hours, the aluminum bag was taken out and visually observed, and judged according to the following criteria. (-) No change, no tendency to solidify (±) Slight solidification (+) Solidification but cannot be pinched with fingers (〓) Solidification is observed and can be picked with fingers (〓) A large lump is observed, and even if you pick it up with your fingers, it is difficult to break it up, and it becomes difficult to dissolve in water. (〓) The entire bag solidified into a block shape and was extremely difficult to dissolve. (3) Flowability test method Flowability test method for powders [Pesticide Production Technology 22 , 54
(1970)], the vibrator (National
EU-17) directly connected to a cylinder (inner diameter 50mm, height 55mm)
Place a 10-mesh wire mesh at the bottom of the tube (mm), place 50 g of the sample on it, start the vibrator, and start the first
The time (seconds) from the point when 10 g was dropped until the next 30 g was dropped was measured. The preferred fluidity is within 20 seconds. (4) Coefficient of variation of active ingredients One day after storing the hydrating agent in the product storage tank (1 mm x 1 mm x 1 mm), 0.1 g samples were collected from 5 locations at 20 cm intervals in the height direction of the tawak. Methomyl was extracted with 20 ml of acetonitrile, the content of methomyl was measured by cargo chromatography, and the coefficient of variation was determined using the following formula. This coefficient of variation indicates the dispersion of methomyl in the wettable powder, and the larger the value, the greater the dispersion. Coefficient of variation (CV) = Standard deviation of 5-point measurements / Average value of 5-point measurements x 100 (Test Example 1) Dust generation and solidification test Methomyl raw material 52 parts, dust generation prevention agent 0.5 to 4.0 parts, A hydrating powder containing 3 parts of zeolite and the remainder of ground ammonium sulfate (100 parts in total) was produced in accordance with Example 2, and was subjected to dusting and solidification tests. The results are shown in Table 1.
In the table, PPG indicates polypropylene glycol, and the number with a # in parentheses indicates the average molecular weight of polyethylene glycol or propylene glycol (same in the following test examples).

【table】

[Table] (Test Example 2) Dust generation and solidification test A composition of 52 parts of methomyl raw material, 3 parts of dust prevention agent, 3 parts of zeolite and 42 parts of ground ammonium sulfate was prepared according to Example 1. Dust generation and solidification tests were conducted on the wettable powder. The results are shown in Table 2.

[Table] (Test Example 3) Dust generation property, fluidity, and coefficient of variation of active ingredient A composition of 52 parts of methomyl raw material, 3 parts of dust generation inhibitor, 3 parts of zeolite, and 42 parts of ground ammonium sulfate. The wettable powders were homogenized by mixing and stirring according to 1. Dust generation and fluidity tests were conducted, and the coefficient of variation of the active ingredient was measured. Table 3 shows the test results for hydrating powders manufactured under conditions of a manufacturing workplace temperature of 5°C, relative humidity of 40%, and sunny weather. Table 4 shows the test results of the wettable powders.

【table】

[Table] From the above results, the products of the present invention are superior to those of the comparison group in dust generation prevention properties, anti-caking properties, and fluidity, and are almost unaffected by weather conditions during production. It is recognized that a hydrating agent with less variation in active ingredients can be obtained.

Claims (1)

[Claims] 1 S-methyl-N-[(methylcarbamoyl)
An insecticide comprising a composition containing oxy]thioacetimidate and a water-soluble carrier, the composition containing 1% by weight or more of one or more compounds selected from glycerin and polypropylene glycol having an average molecular weight of 400 to 1200. Hydrating agent. 2. The insecticide wettable powder according to claim 1, wherein the composition contains oil-absorbing mineral fine powder. 3. Claim 1 in which the water-soluble carrier is ammonium sulfate, sodium sulfate or urea.
Insecticide hydrate according to item 1 or 2. 4. The insecticide hydrate according to claim 2 or 3, wherein the oil-absorbing mineral fine powder is zeolite or diatomaceous earth.