JPH01226802A - Agent for imparting sustained release to pesticide, sustained release pesticide and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject sustained release pesticide containing particle nuclei of an effective component prepared by using hydrophobic fine powder as an agent for imparting sustained release, making the hydrophobic fine powder adhere to the surface of another powder absorbing a liquid effective component of the pesticide at a constant ratio and carrying out fixation or film formation thereof. CONSTITUTION:The objective sustained release pesticide containing particle nuclei of an effective component prepared by using hydrophobic fine powder such as stearic acid, aluminum stearate, titanium dioxide treated with aluminum laurate and polystyrene as an agent for imparting sustained release, making to adhere the fine powder with a powder size <=1/5 diameter of another powder absorbing a liquid effective component of the pesticide to the surface of this higher-sized powder in an amount of 0.05-1pt.wt. based on 1pt.wt. this higher- sized powder and carrying out fixation or film formation thereof. The resultant pesticide can maintain the excellent drug-efficacy for a long period and reduce damages to crops.

Description

DETAILED DESCRIPTION OF THE INVENTION 1) Purpose of the invention (1) Industrial application field The present invention relates to a sustained release method for improving the sustained release properties of a liquid agricultural chemical active ingredient in an agricultural chemical formulation containing the active ingredient. The present invention relates to a sex-imparting agent, a new sustained-release pesticide containing the same, and a method for producing the same.

More specifically, the present invention provides a sustained-release agent for a liquid agricultural chemical active ingredient made of a hydrophobic fine powder, and a particle of the powder on the surface of the powder that has absorbed the liquid agricultural chemical active ingredient. A hydrophobic fine powder having a particle size of one-fifth or less of the particle size is attached, immobilized or formed into a film at a ratio of 1 part by weight of O,OS to 1 part by weight of the amount of the powder, The present invention relates to a sustained-release agricultural chemical characterized by containing the thus obtained active ingredient particle cores, and further to a method for producing a sustained-release agricultural chemical characterized by forming the active ingredient particle cores by the above-described method.

(2) Prior art In the past, many attempts have been made to achieve sustained release of various agricultural chemical active ingredients in liquid or liquid form. Conventional sustained-release pesticides can be roughly divided into: (1) A method of micro-encapsulating the active ingredient of the pesticide (Japanese Patent Laid-Open No. 144304/1983, Japanese Patent Laid-Open No. 59/1989
-20209 Publication), ■Method of clathrating pesticide active ingredients with cycdextrin (Japanese Unexamined Patent Publication No. 58-216
(See Japanese Patent Application Laid-Open No. 59-53401).

There is a method of coating agrochemical preparations such as zero granules and powders with wax or various resins (see JP-A-57-126402 and JP-A-60-202801). However, no attempt has been made so far to improve the sustained release properties of liquid agricultural chemical active ingredients by, for example, attaching hydrophobic fine powder to the particle surface of the liquid agricultural chemical active ingredients.

(3) Problems to be solved by the invention When liquid pesticide preparations such as granules and powders come into contact with water,
The active ingredients contained in the drug may elute at a concentration higher than that required to exert a biological effect. In such cases, the pesticide may cause chemical damage to the crop, such as leaf blight or growth suppression, or the active ingredient of the pesticide once eluted decomposes and disappears in water or soil, or disappears due to photolysis. As a result, the residual effect period of the active ingredient may be shortened. Therefore, if it is possible to release the minimum amount of the pesticide active ingredient required for pest control over a long period of time from the pesticide formulation, these problems can be solved. Furthermore, if sustained-release properties are provided, there is no need to repeatedly apply pesticides, which is extremely economical and also useful for preventing environmental pollution. However, the known sustained-release pesticides mentioned above are Each method has its advantages and disadvantages in solving these problems. That is, depending on the type of agricultural chemical active ingredient, there are some that cannot be formulated for sustained release, such as microencapsulation or inclusion with cyclodextrin. Furthermore, even if these formulations can be formulated, it may be difficult to obtain the desired sustained release properties, or the pesticidal effect may be insufficient, resulting in prolongation of residual effects, which is one of the objectives of sustained release, and drug damage. There are many cases in which it is not possible to sufficiently reduce the amount of carbon dioxide released, and furthermore, the technology for formulating pesticides for sustained release is complicated, and the raw materials used for this purpose are expensive, so there are still problems to be solved from a technical or economic perspective. There are many issues that need to be addressed. Therefore, as mentioned above, conventional sustained release techniques are still insufficient.

Development of new sustained release technology is desired.

In view of this situation, the present invention focuses on improving the surface structure of agricultural chemical active ingredients, and provides a new sustained-release agent capable of imparting desired sustained-release properties, and a sustained-release agent made using the same. The purpose of the present invention is to provide a release pesticide and a method for producing the same.

2) Structure of the Invention (1) Means for Solving the Problems The present inventors have conducted extensive research to solve the above problems. As a result, they discovered that by modifying the particle surface of a powder that has absorbed liquid agricultural chemical active ingredients to be more hydrophobic than the particle itself, it was possible to impart preferable sustained release properties. Completed the invention. To be more specific, a liquid pesticide active ingredient is absorbed on the powder particle surface,
A hydrophobic fine powder having a particle size of 1/5 or less of the particle size of the powder is added in an average amount of 0.0% per part by weight of the powder.
After uniformly adhering, immobilizing or forming a film at a ratio of 0.5 to 1 part by weight, the active ingredient particle cores obtained in this way are used to form powders, granules, and water with adjuvants and fillers in the same way as ordinary agricultural chemicals. By formulating it into powders, suspensions, pastes, etc., a desirable sustained release effect is achieved, and along with this, the inherent residual effects of the active pesticide ingredients are maintained, and chemical damage is significantly reduced. We have obtained the knowledge that the desired biological effects such as

Therefore, the first aspect of the present invention relates to a sustained release agent for a liquid agricultural chemical active ingredient, which is characterized by being made of a hydrophobic fine powder.

In addition, the gist of the second invention is that a hydrophobic fine powder having a particle size of one-fifth or less of the particle size of the powder is added to the surface of the powder that has absorbed the liquid agricultural chemical active ingredient. A sustained release agent characterized by containing active ingredient particle nuclei formed by adhering, immobilizing, or forming a film at a ratio of 0.05 to 1 part by weight per 1 part by weight of the powder. Regarding pesticides.

The gist of the third invention is a method for producing a sustained-release agricultural chemical, characterized in that a sustained-release agent is attached, immobilized, or formed into a film by the above-described specific method to form active ingredient particle nuclei. This is related to.

The hydrophobic fine powder used in the present invention is not particularly limited as long as it is a fine powder that is water-repellent to water, or the test method described below may be used because it has a large contact angle and a high kneading property. It is very effective if the measured contact angle is 70 degrees or more. Examples of such hydrophobic fine powder include the following. Of course, it is not limited to these.

■Higher fatty acid stearic acid, palmitic acid, lauric acid, myristic acid, etc. ■Higher fatty acid metal salts aluminum stearate, magnesium stearate, calcium stearate, etc. ■Higher fatty acid metal salt treatment Titanium oxide Aluminum laurate treatment Titanium oxide, aluminum stearate treatment Titanium oxide, etc. ■Hydrophobic white carbon, dimethyldichlorosilane treated silicon dioxide, etc. ■Synthetic resins, etc. Polystyrene, polyamide, silicone, etc.

These may be reprinted or can be used as is, or if necessary, they may be finely ground to reduce the particle size to one-fifth or less of the powder particles containing the pesticide active ingredient. good.

The particle size of the hydrophobic fine powder used in the present invention varies depending on the particle size of the oil-absorbing powder particles used, but
It is desirable that it is 1/10 or less, preferably 1/10 or less. If the size is larger than that, it is difficult to uniformly adhere, immobilize, or form a film the hydrophobic fine powder on the surface of the oil-absorbing powder, and the sustained release function cannot be fully exhibited.

In addition, the amount of hydrophobic fine powder that is attached to the surface of the powder that has absorbed the liquid agricultural chemical active ingredient varies depending on the particle size of the oil-absorbing powder and the particle size of the hydrophobic fine powder, but the amount is 1% of the amount of oil-absorbing powder.
It is effective to deposit the hydrophobic fine powder in an amount in the range of 0.05 to 1 part by weight based on the weight part. Of course, the ratio within this range may be changed as appropriate for the purpose of obtaining optimal sustained release properties. however,
If the amount of the hydrophobic fine powder is less than this, uniform adhesion, immobilization, or film formation will be insufficient, and the sustained release effect will not be sufficiently exhibited. On the other hand, if the amount increases beyond this point and the hydrophobic fine powder adheres excessively around the oil-absorbing powder particles, the sustained release effect will be achieved, but the natural control effect of the active pesticide ingredient will be reduced. Therefore, it is not preferable to use more fine powder than necessary.

The liquid agricultural chemical active ingredient that can be used in the present invention is not particularly limited, and any active ingredient that is used in ordinary agricultural chemical formulations can be used.

Examples include, but are not limited to, the following:

Examples of insecticides CYAP, MPP, MEP, pirimiphos-methyl, diazinon, etrimphos, isoxathion, ESP, marathon, PAP, formothion.

Mecarbam, thiometone, ethylthiometone, prothiophos, DDVP, BRP, CVP, propafos, carbosulfan, allethrin, fenvalerate, pyrethrin, BPPS, DCIP, chlorpicrin, etc.

Examples of fungicides: 0-ethyl-〇,0-bis(2,4-dichlorophenyl) phosphate (hereinafter referred to as "phosdaifen"),
IBP, EDDP, eclomezole, penthiazole,
DPC5 etc.

Examples of herbicides: vernarate, bentiocarb, orthobencarb, molinate, butachlor, pretilachlor, metolachlor, DPA, butamifos, etc.

The generic names of the above-mentioned pesticide active ingredients are from the "Pesticide Handbook 1985 Edition" (Japan Plant Protection Association).
(Published January 30, 1986).

These active ingredients can be effectively used alone or in combination of two or more.

In addition, any powder that has oil-absorbing properties can be used as the powder for oil-absorbing liquid pesticide active ingredients.
Examples include, but are not limited to, the following:

Examples of powders with oil absorption ability include white carbon, silicon dioxide, diatomaceous earth, attapulgite, calcium silicate, aluminum oxide, magnesium hydroxide, acid clay, etc.

Further, the amount of the liquid agricultural chemical active ingredient to be made to absorb oil in the above-mentioned powder may be equal to or less than the oil absorption amount of each powder.

In carrying out the present invention, the method of uniformly adhering, immobilizing, or forming a film of hydrophobic fine powder on the surface of powder that has absorbed liquid agricultural chemical active ingredients is not particularly limited, but for example, I can list the following methods.

(1) Powder containing a predetermined amount of agrochemical active ingredients in oil using a rotating container mixer such as a cylindrical mixer or V-type mixer, or a fixed container mixer such as a ribbon mixer or screw mixer. Prepare by adding the powder and hydrophobic fine powder and stirring to mix.

(2) FA is produced by putting a predetermined amount of oil-absorbed agricultural chemical active ingredient powder and hydrophobic fine powder into a ball mill and rotating it together with the ball.

(3) Powder containing a predetermined amount of oil-absorbed pesticide active ingredient and hydrophobic fine powder are placed in a transfer granulator, and preparation is carried out by rotating the blades.

(4) A predetermined amount of It is prepared by processing a powder that has oil-absorbed pesticide active ingredients and a hydrophobic fine powder.

In addition, when carrying out these methods (1) to (4), heating and cooling may be performed as necessary.

The formulation form of the sustained-release pesticide of the present invention is not particularly limited, and includes powder, DL powder, flow dust, wettable powder, fine granules F, fine granules, granules, suspensions, and hydrated granules. It can be used as a preparation agent, paste, etc., and its preparation may be carried out by ordinary means using commonly used equipment together with the active ingredient particle cores obtained in the present invention, auxiliary agents, and fillers.

As adjuvants used in producing the sustained-release pesticide of the present invention, a wide variety of adjuvants that are commonly used in pesticide formulations can be used. Examples include anionic surfactants and nonionic surfactants such as alkyl sulfates, alkylaryl sulfonic acids, alkyl sulfonic acids, polyethylene glycol ethers, polyethylene glycol esters, and polyhydric alcohol esters. Examples include various antioxidants, ultraviolet absorbers, hydrolysis inhibitors, and physical property improvers.

Moreover, the extenders that can be used in the present invention can be those commonly used in agricultural chemical formulations. Examples include clay,
Kaolin, sericite, gicrite, talc, acid clay, calcium carbonate, magnesium carbonate, gypsum, diatomaceous earth, pumice, zeolite, perlite, vermiculite,
Minerals such as attapulgite and bentonite, natural products such as starch and cellulose, quijirole, methyl alcohol, ethyl alcohol, ilobrovir alcohol,
Examples include organic solvents such as glycerin, ethylene glycol, propylene glycol, propylene glycol methyl ether, and methylnaphthalene, and water.

(3) Examples Examples are given below to specifically explain the present invention, but the present invention is not limited to these examples. , all parts by weight.

Example 1 After adding 2 parts of phosdaifen to 2 parts of Sasno white carbon (average secondary particle size 6 gm) and making it absorb oil, jet-
O-Mizer (manufactured by Seishin Enterprise Co., Ltd.) was applied to obtain a fluid oil-absorbing powder.

Titanium oxide MT-Zo is added to 4 parts of this oil-absorbing powder.

One part of S (trade name of titanium oxide treated with aluminum laurate manufactured by Teikoku Kako Co., Ltd., average particle size 0.015 JLm, contact angle 145 degrees) was placed in a Mechano Mill (trade name of a ball mill type mixer manufactured by Okada Seiko Co., Ltd.) and set the powder temperature to 5.
Mix at 0° C. and 400 rpm for 30 minutes. In this way, phosdaifen particle nuclei (to which hydrophobic fine powder was attached, immobilized, or formed into a film: hereinafter referred to as "particle nuclei") were obtained.

5.1 parts of this phosdaifene particle core (purity 39.2%), isopropyl acid phosphate (physical property improver)
0.2 parts and 94.7 parts of clay were mixed in a hammer mill to obtain a powder containing 2.0% of phosdaifen.

Example 2 Wettable powder Phosdaifen particle core prepared in Example 1 (purity 39.
2%), 2 parts of white carbon, 2 parts of polyoxyethylene phenyl ether, 2 parts of calcium lignin sulfonate, and 55.7 parts of finely powdered clay were mixed in a hammer mill to create a wettable powder containing 15% as phosdaifen. I got it.

Example 3 Marathon 2 to 3 parts of Koino Diaiso ± (average particle size 11 um)
After the mixture was added to absorb oil, it was passed through a jet-mizer to obtain a fluid oil-absorbing powder. 1 part of Aerosil R-972 (trade name of dimethylchlorosilane-treated silicon dioxide manufactured by Hiki Aerosil Co., Ltd., average particle size: 0.016 gm, contact angle: 155 degrees) was mixed with 4 parts of this oil-absorbing powder for 120 minutes using a V-type mixer. Then, Aerosil R-972 (hydrophobic fine powder) was uniformly adhered to the powder surface on the Marathon oil-absorbing diatomaceous material.

4.8 parts of this marathon particle core (purity 31.5%), 0.2 parts of isopropyl acid phosphate, and 95.0 parts of clay were mixed in a hammer mill to obtain a powder containing 1.5% as marathon.

Example 4 am After adding 1 part of butachlor to 2 parts of attapulgite (average particle size 40 JLm) and making it absorb oil, jet-
- A fluid oil-absorbing powder was obtained by passing through a miser. Add 4 parts of this oil-absorbing powder to titanium oxide MT-100T (trade name of aluminum stearate treated titanium oxide manufactured by Teikoku Kako Co., Ltd., average particle size 0.015 gm, contact angle 140
Titanium oxide M
T-100T (hydrophobic fine powder) was uniformly immobilized to obtain butachlor particle cores.

19.2 parts of this butachlor particle core (purity 26.1%), 1 part of polyvinyl alcohol, 20 parts of bentonite and 59.8 parts of clay were mixed in a hammer mill, granulated in an extrusion granulator, and after drying, The particles were sized (14 to 32 meshes) to obtain granules containing 5% butachlor.

3) Effects of the invention (1) Effects of the invention The sustained-release pesticide of the present invention can be used as an insecticide, fungicide, herbicide, etc. in plant foliage, soil, or water, depending on the intended use of the active ingredient contained therein. When sprayed, first of all, the active ingredient can be released in a sustained manner from the pesticide. As a result, excellent medicinal efficacy can be sustained for a long period of time compared to when sustained release technology is not applied, and furthermore, chemical damage to crops can be reduced. Secondly, as mentioned above, the amount of hydrophobic fine powder to be used (0.05 to 1 part) and the particle size (one-fifth or less) to be attached to the surface of the powder that has oil-absorbed agricultural chemical active ingredients. By appropriately selecting the conditions, it is possible to freely control the elution rate of the active ingredient by increasing or decreasing it. Thirdly, the sustained-release pesticide of the present invention is easy to prepare in the same way as general pesticides. Fourthly, the sustained-release pesticide of the present invention can be used for many pesticide active ingredients, and has a wide range of applicability.

(2) Test example Test examples will be given to prove the above-mentioned usefulness of the present invention.

Test Example 1 Dissolution test of pesticide active ingredient in water (confirmation of sustained release) 500 m 1 of ion exchange water was placed in a 1M flask, and particles of pesticide active ingredient prepared according to Examples 1 to 4 were added to this. The kernels are added in an amount equivalent to 250 mg as the amount of pesticide active ingredient. Then, using a dissolution tester (Model NTR-VS6 manufactured by Toyama Sangyo Co., Ltd.), the water temperature was kept at 20°C, and
Stir at 0 rpm. After a predetermined time, a sample was taken from the flask, the concentration of the active ingredient in the water (ppm) was measured, and the dissolution rate (%) was calculated using the following formula.

Note that the contact angle of the hydrophobic fine powder was measured by the following method.

(Method for measuring hydrophobicity of fine powder)
) with a diameter of 8.5 mm and a weight of 100 mg.
Next, ion-exchanged water is dropped onto the surface of the tablet using a microsyringe, and the contact angle of the water droplet is measured 1 minute after dropping using a goniometer (Model G-1, manufactured by Elma Optical Co., Ltd.).

According to this test, if sustained release properties are provided, the dissolution rate (%) in water becomes smaller. The dissolution rate gradually increases with the passage of time.

The test results are shown in Table 1. According to this, it was revealed that the agricultural chemical of the present invention has sustained release properties.

Test Example 2 Rice blast control effect test (residual effect determination) After rice (variety Akihikari) was soaked and germinated, it was sown in rows in a field prepared in a plastic greenhouse.
At the 3-leaf stage 28 days after sowing, a powder prepared according to Example 1 was spread using a simple spreader in an amount equivalent to 3 kg/10 a. Two days after spraying, rice blast fungi (Pyricularia oryza
zae: Approximately 3 c of diseased leaves of Pyricularia oryzae)
They were cut into m square pieces and scattered over the entire test area, and used as an inoculation source to ensure constant infection with rice blast. In the disease onset investigation, the percentage of diseased area (%) of rice blast disease was investigated over time at intervals of 3 to 4 days starting 7 days after inoculation, and the control value (%) was calculated using the following formula. The average control value (
X) was found.

In addition, instead of the phosdaifen particle core of Example 1, a drug prepared using a phosdaifen drug substance was used as a comparative drug.

The results are shown in Table 2.

Test Example 3 Insecticidal effect and persistence test against black leafhopper A powder prepared according to Example 3 was applied to rice (variety: Nipponbare, 5 plants per plant, 4-leaf stage) grown in pots with a diameter of 11 cm as midgets. An amount equivalent to 3 kg/10 a was sprayed using a duster. Thereafter, they were placed in a glass chamber, and after a predetermined number of days, the rice bodies were covered with a vinyl chloride cylinder with a diameter of 11 cm and a height of 30 cm, and 10 female adult leafhoppers were released into this. After 24 hours, the number of living and dead piles was checked, and the insect killing rate (%) was determined. This study was conducted using a 3-bot system, and the average mortality rate (%
) was sought.

In addition, a drug prepared using Marathon drug substance instead of the Marathon particle core of Example 3 was used as a comparative drug.

The results are shown in Table 3.

Test Example 4 Weeding effect and phytotoxicity test Paddy soil (alluvial loam) was filled in a pot with a size of 1/5000 are, and chemical fertilizer (17:17
:17) was fertilized at 3g per pot, and the pot was flooded with water.

■Pharmaceutical damage test Three paddy rice seedlings (Shin8 Nipponbare) at the 2rJ stage were transplanted per pot, and on the third day after transplanting, granules prepared according to Example 4 were applied at a rate of 93 kg per ioR. The plating depth was set at 5 cm. The investigation measured the translocation of aboveground rice plants 211 days after chemical treatment.

This test was conducted using a 3-pot system, and the untreated plot ratio (%) was determined using the following formula.

Type of treatment area Untreated area ratio (X) = (1-) x to.

Model for untreated area: mf! J11. ,, was used as comparative drug 1.

The results are shown in Table 4.

(2) Effect test The same granules as above were sprinkled at a rate of 3 kg per 10 are into pots with a size of 1/5000 are filled with water. 10 days after treatment, 20 days after treatment, 30 days after treatment, 4
After 0 and 50 days, 20 germinated seeds of Japanese millet were sown per pot, and the water depth was set to 3 cm. The survey was conducted after 24 days from each sowing date by pulling out the Japanese millet and drying it.
Ji-(g) was measured, and the weeding rate (%) was determined using the following formula.

This test was conducted in triplicate, and the average weeding rate (%) was determined.

The results are shown in Table 4.

Claims (1)

[Scope of Claims] 1) A sustained release agent for agricultural chemicals containing a liquid agricultural chemical active ingredient, which is made of hydrophobic fine powder. 2) On the surface of the powder that has absorbed the liquid pesticide active ingredient, add hydrophobic fine powder with a particle size of one-fifth or less of the particle size of the powder, per 1 part by weight of the amount of the powder. A sustained-release agricultural chemical characterized by containing 0.05 to 1 part by weight of active ingredient particle nuclei formed by adhesion, immobilization, or film formation. 3) On the surface of the powder that has absorbed the liquid pesticide active ingredient, add hydrophobic fine powder with a particle size of one-fifth or less of the particle size of the powder, per 1 part by weight of the amount of the powder. A method for producing a sustained-release agricultural chemical, which comprises adhering, immobilizing or forming a film in a proportion of 0.05 to 1 part by weight to form active ingredient particle nuclei.