JP3208805B2 - Hydrating pesticide composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wettable pesticidal composition such as a wettable powder and the like. The present invention relates to a hydratable pesticidal composition having greatly improved workability during spraying.

[0002]

2. Description of the Related Art In recent years, in pesticide preparations such as insecticides, fungicides and herbicides, the storage stability of the pesticide active ingredient (pesticide drug substance) in the preparation, the workability at the time of application, and the application effect ( Due to the uniformity of the pharmacological effect), wettable powder-type wettable pesticidal compositions which are used by adding water at the time of application are widely used.

[0003] This hydratable pesticidal composition is usually made of clay,
A pesticidal active ingredient is supported on a pesticidal carrier such as talc, diatomaceous earth, kaolin, bentonite, and hydrated silicon dioxide (commonly referred to as silica or white carbon), and a surfactant, a stabilizer, and other necessary substances After adding the additive, the mixture is pulverized and mixed by, for example, a hammer mill or the like to produce the mixture.

[0004] However, it is known that the pesticidal composition obtained in this manner gradually undergoes hydrolysis of the pesticidal active ingredient in the composition, and the content thereof decreases with time. Therefore, in such hydratable pesticidal compositions, it is extremely important in practice to maintain the stability over time, and various proposals have been made for maintaining or improving this stability. I have.

[0005] For example, Japanese Patent Application Laid-Open No. 57-156402 discloses an invention relating to a mineral carrier for agricultural chemicals in which a mineral such as clay, talc, bentonite or the like is heat-treated at a calcination temperature of 800 ° C or more.

Japanese Unexamined Patent Publication (Kokai) No. 59-53402 relates to a fenitrothion wettable powder in which fenitrothion is supported on calcined synthetic hydrous silicon oxide to suppress separation of the original fenitrothion into oil droplets during hydration. The invention is disclosed, and Japanese Patent Publication No. 1-55241 discloses an invention of a pesticidal composition in which a pesticidal active ingredient is supported on hydrous silicic acid having a loss on ignition of 2% by weight or less.

Further, Japanese Patent Application Laid-Open No. Hei 3-163006 discloses that an agricultural chemical raw material having a melting point of 70 ° C. or less, a calcined product of wet-process silica, and a surfactant are used as essential components. An invention relating to a granular wettable powder obtained by granulation is disclosed.

[0008]

SUMMARY OF THE INVENTION These known inventions are:
It is effective to some extent to suppress the hydrolysis of the pesticidal active ingredient and prevent the pesticidal active ingredient from being separated from water in the form of oil droplets, thereby maintaining and improving the storage stability of the pesticidal composition.

However, in such a known hydratable pesticidal composition, the carrier carrying the pesticidal active ingredient during hydration aggregates with the pesticidal active ingredient with time and settles at the bottom of the container, and it becomes difficult to work. It is known to cause various disadvantages.

That is, the uniformity of dispersion of the pesticidal active ingredient in a so-called wettable pesticidal composition such as a wettable powder is considerably influenced by the dispersibility (cohesion) of the carrier carrying the active ingredient in water. Is done.

As is well known, sedimentable silica has been widely used as a porous powder as a carrier for agricultural chemicals because of its high oil absorbing ability. Many hydroxyl groups (OH groups, silanol groups) are present on the surface of the particles of the precipitated silica, and due to its chemical properties, the silica is liable to coagulate and settle together with the agricultural chemical active ingredient in the wettable powder.

[0012] Accordingly, it has been conventionally required to prevent the coagulation and sedimentation of the carrier and / or the pesticidal active ingredient over time during the hydration of such a hydratable pesticide composition.

[0013]

Means for Solving the Problems and Actions In order to meet the above-mentioned demands, the present inventors have conducted intensive studies on the cause of the above-mentioned coagulation and sedimentation in a hydratable pesticide composition and a method for solving the problem. It has been found that by adjusting the hydroxyl group density on the particle surface within a certain range, the coagulation sedimentation property of the wettable powder can be considerably suppressed, and further studies on the optimum density of the hydroxyl group have revealed that the density of the hydroxyl group was 3.5. It has been found that the coagulation and sedimentation properties of the above-mentioned wettable powder can be significantly improved when the number of particles / nm ² or less is used.

That is, according to the study of the present inventors, the surface hydroxyl group density of precipitated silica conventionally used as a carrier of a hydratable agricultural chemical composition is usually about 8 to 10 / nm ² ,
At least 5 particles / nm ² were obtained. However, when such silica is used as a wettable powder as a carrier for agricultural chemicals, the silica is remarkably aggregated and settled.

[0015] However, a pesticidal active ingredient, particularly a component having a melting point of 70 ° C or less, is supported on a precipitated silica having a surface hydroxyl group density of 3.5 / nm ² or less, and is prepared by mixing with a surfactant and preparing. When the pesticide composition is suspended and dispersed in water, the sedimentation is remarkably reduced, and shows stable dispersibility. Therefore, the workability of spraying, the uniformity of the pesticide active ingredient are improved, and the hydratable pesticide is improved. The inventors have found that the composition has very suitable characteristics, and have completed the present invention.

Accordingly, the present invention provides a hydratable pesticidal composition containing an agricultural chemical active ingredient, a carrier for supporting the agricultural chemical active ingredient, and a surfactant, wherein one or more of the aforementioned agricultural chemical active ingredients are contained. Has a melting point of 70 ° C. or less;
Provided is a hydratable pesticide composition characterized by using a precipitated silica having a surface hydroxyl density of 3.5 particles / nm ² or less as the carrier.

Although the reason why the hydratable pesticidal composition according to the present invention provides the above-mentioned excellent effects is unknown, it is not possible to use only precipitated silica having a surface hydroxyl group density of 3.5 particles / nm ² or less. Since it does not provide high anti-coagulation and sedimentation prevention properties, the silica, the pesticidal active ingredient carried thereon, and the surfactant for suspending and dispersing the silica carrying the pesticidal active ingredient in water are synergistically synthesized. It seems to act to give high dispersion stability.

Hereinafter, the present invention will be described in more detail. The hydratable agricultural chemical composition of the present invention comprises an active agricultural chemical ingredient, a carrier carrying the same, and a surfactant. It is used in a turbid state.

[0019] Here, in the present invention, the surface hydroxyl density of the carrier is 3.5 pieces / nm ² or less, more preferably using 3.0 groups / nm ² or less is precipitated silica. In a precipitating silica having a surface hydroxyl group density of more than 3.5 particles / nm ² , when a hydratable pesticidal composition having an active pesticide supported thereon is suspended and dispersed in water, coagulation and sedimentation increases. The object of the invention cannot be achieved.

Various properties other than the surface hydroxyl group density of the precipitated silica carrier used in the present invention are variously selected, but from the viewpoint of dispersibility in water and workability during preparation of the preparation, the water vapor adsorption specific surface area is 15 to 45 m ² / cm ² . g is preferable. Further, the oil absorption is preferably 200 to 350 ml / 100 g, and the average particle size is usually in the range of 1 to 10 μm.

The precipitable silica having a surface hydroxyl group density as described above is obtained by subjecting the precipitable silica obtained by an ordinary known method to, for example, heat treatment at 700 to 1000 ° C. for 10 to 120 minutes or silane coupling treatment. Can be obtained.

On the other hand, as the pesticidal active ingredient supported on the precipitated silica, one or a mixture of two or more pesticidal active ingredients having a melting point of 70 ° C. or less is used from the viewpoint of preventing sedimentation and aggregation. The following are illustrated as such pesticidal active ingredients.

O, O-dimethyl-O- [3-methyl-4
-(Methylthio) phenyl] thiophosphate (liquid) O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate (liquid) (fenitrothion) dimethyldithiophosphorylphenylacetate ethyl (liquid) (2-isopropyl -4-methylpyrimidyl-6) -diethylthiophosphate (liquid) dimethyldicarbethoxyethyldithiophosphate (liquid) 3-phenoxybenzyl = (1RS, 3RS)-(1R
S, 3RS) -3- (2,2-dichlorovinyl) -2,
2-dimethylcyclopropanecarboxylate (liquid) (RS) -α-cyano-3-phenoxybenzyl = (R
S) -2- (4-Chlorophenyl) -3-methylbutanoate (liquid) O-ethyl-S, S-diphenyldithiophosphate (liquid) penta-4-enyl = N-furfuryl-N-imidazole-1- component liquid at room temperature such as ylcarbonyl -DL- Homoaraninato (liquid) (pefurazoate).

O, O-diethyl-O-3,5,6-trichloro-2-pyridyl phosphorothioate (mp4
3 ° C.) O, O-dimethyl-S [5-methoxy-1,3,4-thiadiazol-2 (3H) -onyl- (3) -methyl] dithiophosphate (mp 39 ° C.) O, O— Diisopropyl-S-benzylthiophosphate (mp 23 ° C.) 2-methyl-4-chlorophenoxythioacetate-S-ethyl (mp 41 ° C.) isopropyl-N- (3-chlorophenyl) carbamate ( mp 42 ° C.) S-1-methyl-1-phenylethyl = piperidine-1
-Carbothiate (mp 39 ° C) Ethyl paranitrophenylthionobenzenephosphonate (mp 36 ° C) 2-secondary-butylphenyl-N-methylcarbamate (mp 32 ° C) 2- (4- Ethoxyphenyl) -2-methylpropyl =
3- phenoxybenzyl ether (mp 36.4)
(38.0 ° C.) (Etofenprox), a wax-like component at normal temperature.

O, O-diethyl-O- (3-oxo-2
-Phenyl-2H-pyridazin-6-yl) phosphorothioate (mp 55 ° C) O, O-dimethyl-S- (N-methylcarbamoylmethyl) diphosphate (mp 51 ° C) 3-diethoxyphosphoryl Thiomethyl-6-chlorobenzoxazolone (mp 48 ° C) 2-Methoxy-4H-1,3,2-benzodioxaphosphorin-2-sulfide (mp 55 ° C) (E) -4 -Chloro-α, α, α-trifluoro-N-
(1-Imidazol-1-yl-2-propoxyethylidene) -o-toluidine (mp 63 ° C.) N-butyl-N-ethyl-α, α, α-trifluoro-
2,6-dinitro-p-toluidine (mp 66 ° C.) N- (1-ethylpropyl) -3,4-dimethyl-2,
A component that is solid at room temperature, such as 6-dinitroaniline (mp 58 ° C.), but becomes liquid or semi-solid depending on the temperature during preparation.

As the surfactant used in the present invention, any of the surfactants commonly used in wettable pesticidal compositions can be used. For example, alkylaryl sulfonates, naphthalenesulfonic acid formalin condensates, ligninsulfonic acid One or two of salt, dialkyl sulfosuccinate, polyoxyethylene alkyl aryl ether sulfate, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, fatty acid polyoxyethylene sorbitan, sorbitan alkyl ester, etc.
More than one species can be used in combination. The amount of the surfactant used may be a usual amount, and is generally 1 to 10% by weight of the whole composition.

The pesticidal composition of the present invention may further contain, as necessary, fillers such as powders of commonly used mineral substances such as wax, quartzite, quartz sand, pottery stone, kaolin, diatomaceous earth, terra alba, talc, calcium carbonate, and attapulgite. Powders of ammonium sulfate, urea, sucrose, glucose, sodium sulfate, potassium chloride and the like, and other various additives used in the hydratable pesticide composition can also be blended.

[0028]

EXAMPLES Hereinafter, the present invention will be described in detail by showing production examples of the precipitated silica carrier used in the present invention, and showing examples and comparative examples. However, the present invention is limited to the following examples. Not something.

Production Example A commercially available sodium silicate No. 3 was diluted to a specific gravity of 1.07 (55 ° C.), and 5 liters of the diluted solution was placed in a reaction tank and stirred at a temperature of 92 ± 2 ° C. under a temperature of 92 ± 2 ° C. 300 ml of 0.5% sulfuric acid are added in 35 minutes.

After adding sulfuric acid, aging is performed for 40 minutes. After aging, the pH of the reaction slurry was adjusted to 4.0 while allowing to cool,
Next, the product is filtered and washed with Nutsche to wash out and separate reaction by-products (sodium sulfate).

The washed cake is again slurried and adjusted to pH
Adjustment is performed, and after filtration, filtration and washing are performed again. Next, a precipitated silica powder was obtained by drying and pulverization.

500 g of the precipitated silica was placed in an iron tray, and heated in an electric furnace at 870 ° C. for 1 hour.
This was designated as silica (1).

Further, 500 g of the precipitated silica obtained in the same manner as above was heated at 900 ° C. for 0.5 hour to obtain silica (2).

Table 1 shows the properties of the above silicas (1) and (2).
Shown in Table 1 also shows properties of commercially available silicas A and B.

[0035]

[Table 1]

The density of surface hydroxyl groups was measured by the following method. Measuring method of surface hydroxyl group density [Reference: Hiromitsu Naono et al., Surface 29 (5), 362 (1991)] Full-automatic water vapor adsorption measuring apparatus "BELS" manufactured by Bell Japan Co., Ltd.
Using ORP18 "(trade name), the amount of water vapor adsorbed on silica is measured at 25 ° C. at 5 or more points by a volumetric method. From the relationship between the adsorption relative pressure (X = P / P _O ) and the adsorption amount (V), B
The monolayer adsorption amount (V _m ) of water is calculated by the least square method according to the ET equation.

[0037]

(Equation 1) P: Water vapor pressure at the time of adsorption equilibrium P _O : Saturated vapor pressure of water at 25 ° C. C: Constant V, V _m : [cm ³ (STP) / g]

On the other hand, the specific surface area (S _N2 (a fully automatic nitrogen adsorption measuring apparatus “BELSORP2” manufactured by Bell Japan Co., Ltd.) determined by the BET equation from the nitrogen adsorption measurement at the liquid nitrogen temperature.
8 ”(trade name)) and the amount of water adsorbed on the monolayer (V
_m ) to determine the surface hydroxyl group density.

[0039]

(Equation 2)

Examples 1 and 2, Comparative Examples 1 and 2 20 parts of pefurazoate, 3 parts of sodium ligninsulfonate, 1 part of fatty acid polyoxyethylene sorbitan, 1 part of sodium polyoxyethylene lauryl ether sulfate ,
30 parts of the silica and 45 parts of the clay were mixed and pulverized to obtain a pefurazoate-containing hydratable pesticide composition.

Examples 3 and 4, Comparative Examples 3 and 4 40 parts of fenitrothion, 3 parts of sodium alkylbenzenesulfonate, 1 part of formalin condensate of naphthalenesulfonic acid,
40 parts of the silica and 16 parts of the clay were mixed and pulverized to obtain a fenitrothion-containing hydratable pesticide composition.

[Examples 5 and 6, Comparative Examples 5 and 6] Etofenprox (10 parts), polyoxyethylene alkylphenol ether (2 parts), naphthalenesulfonic acid formalin condensate (2 parts), silica (20 parts) and clay (66 parts) were mixed and pulverized. Thus, a wettable pesticidal composition containing etofenprox was obtained.

Next, the coagulated sedimentation amount of the hydratable pesticide composition was evaluated by the following method. Table 2 shows the results. Coagulation and sedimentation measurement method 3.3 g of the hydratable pesticide composition is weighed into a 100-ml stoppered graduated measuring cylinder, and the volume is adjusted to a constant volume by adding hard water three times.

Next, the graduated cylinder was stoppered, vigorously inverted 30 times, then allowed to stand, and the volume of the sediment after 30 minutes had elapsed was determined as the amount of coagulated sediment. In this case, if the amount of coagulation and sedimentation is 2 ml or less, it is evaluated to have practically sufficient coagulation and sedimentation prevention properties.

[0045]

[Table 2]

From the results shown in Table 2, the surface hydroxyl density was 3.5.
It is recognized that the hydratable pesticidal composition in which the pesticidal active ingredient is supported on sedimentable silica having a particle size of not more than ² particles / nm ² is capable of remarkably suppressing coagulation and sedimentation when dispersed in water.

[0047]

The hydratable pesticidal composition of the present invention, when suspended and dispersed in water, exhibits high dispersion stability and hardly causes coagulation and sedimentation. For this reason, while being excellent in pesticide spraying workability,
The intended effect is exhibited effectively without a decrease in the concentration of the pesticidal active ingredient in the dispersion.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Kunihiko Sasaki, Inventor 9-3 Kaitsuki, Hiratsuka-shi, Kanagawa (72) Shigeyuki Nagao, 413 Higashitaitai, Tamano-shi, Okayama (56) References JP-A-52-78840 (JP, A JP-A-57-169406 (JP, A) JP-A-3-163006 (JP, A) JP-B-1-55241 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) A01N 25/14 A01N 25/08 A01N 31/14 A01N 47/38 A01N 57/14

Claims (2)

(57) [Claims] 1. A hydratable pesticide composition containing an agricultural chemical active ingredient, a carrier carrying the agricultural chemical active ingredient, and a surfactant, the melting point of one or more mixtures of said agricultural chemical active ingredients. Is 70 ° C. or less, and a sedimentable silica having a surface hydroxyl density of 3.5 particles / nm ² or less is used as the carrier. 2. The wettable pesticidal composition according to claim 1, wherein the precipitated silica has a water vapor adsorption specific surface area of 15 to 45 m ² / g.