JPS5943441B2 - Pesticide aqueous suspension - Google Patents

Description

[Detailed description of the invention] The present invention relates to aqueous suspensions of agricultural chemicals.

If the active ingredient of the pesticide is poorly soluble in water or cheap solvents,
A suspension can be prepared by dispersing the finely pulverized raw material in a medium.

This suspending agent includes an oil-based suspension using a non-aqueous solvent such as mineral oil, animal or vegetable oil, etc. as a dispersion medium, and an aqueous suspension using water as a dispersion medium.

When applying pesticides, they generally do not generate dust during handling and are easy to handle quantitatively, and in addition to the usual highly diluted spray solution, it is possible to prepare concentrated spray solutions that are diluted with a small amount of water or other solvents. Moreover, it is desirable to use it as a suspending agent because the effectiveness can be expected to increase by making it atomized, but on the other hand, the dispersed particles in the suspending agent tend to settle, forming a strong sediment layer at the bottom of the container9. Bird Caking “(Hard C
coagulation), dispersed particles strongly aggregate with each other, and when a suspending agent is added to a diluent for dispersion such as water, agglomerates are formed that are difficult to redisperse into individual particles.
This is unavoidable because physical properties deteriorate during storage, such as coagulation.

In particular, these phenomena are accelerated during high temperatures in the summer, and become a fatal defect as a suspending agent, resulting in almost no commercial value.

Various methods have been attempted to prevent deterioration of physical properties of agricultural chemical suspensions during storage.

For example, in the case of aqueous suspensions, a method of stabilizing the suspension by using an aqueous concentrated solution of an inorganic salt such as ammonium sulfate or sodium dihydrogen phosphate as the suspending medium (JP-A-50-1989-1)
76236), a method of stabilizing an aqueous dispersion by adding a metal complex compound dye consisting of an azo dye-complex compound and a phthalocyanine dye-complex compound system (JP-A-49-126)
No. 635) etc. are known.

The present inventors have conducted extensive research in order to prevent deterioration of physical properties during storage when solid agricultural chemicals that are sparingly soluble in water are prepared into aqueous suspensions using water as a dispersion medium. One or more of finely pulverized petroleum resins, coumaron resins, and ester gums are added to the suspension, and a water-soluble polymer compound with a relatively low degree of polymerization is further added to increase the viscosity of the suspension at 20°C. It has been found that by setting the particle size to 200 centipoise or more, deterioration of physical properties such as the formation of a solid precipitated layer that is difficult to redisperse due to sedimentation during storage can be significantly improved, and a stable aqueous pesticide suspension can be obtained. Ta.

The deterioration of physical properties of aqueous suspensions during storage is relatively slow at temperatures below 30°C, but is significantly accelerated at temperatures above 40°C.

In addition, it can be said that generally, the less deterioration of physical properties occurs under high-temperature conditions of 40°C or higher, the less the deterioration of physical properties occurs even at 30°C or lower.

Therefore, the standard for stability during storage of an aqueous suspension is 4.
Relatively short period of time (2-4 weeks) under high temperature conditions of 0-50℃
You can know by observing.

The gist of the present invention is to add resins such as petroleum resins, coumaron resins, and ester gums as fine particles to an aqueous suspension using water as a dispersion medium of solid agricultural chemicals that are poorly soluble in water. By suspending the molecular compound, the suspending agent is given appropriate viscosity and thixotropic properties that last for a long period of time, and the deterioration of physical properties during storage is prevented.

Generally, the viscosity of a suspending agent decreases over time, the amount of chicken tropism decreases, hard caking, etc. are formed, and the physical properties deteriorate.

One of the causes of this is the particle growth of the main agent in the suspending agent, especially the disappearance of fine particles, but the resins used in the present invention do not cause particle growth and the viscosity of the suspending agent decreases over time. It is considered that suppressing the quantitative decrease in chickentropy is the reason why the effect is particularly excellent.

The resins used in the present invention have a melting point of 60°C or higher, are insoluble and stable in water, do not swell, are glassy and are easily pulverized, and have a specific gravity of 0.95 to 1.20/25°C. It has good properties and does not easily float or sink in water.
It is important that they do not physically or chemically react with the active ingredients of pesticides.

Examples of such resins include petroleum resins, coumaron resins, and ester gums, with ester gums being particularly preferred.

The above resins contribute 0.1 to 10% by weight of the suspending agent, preferably 0.
．． It contains 5 to 5% by weight and is used as fine particles.

The fine particles referred to herein are particles of several microns or less, and the smaller the suspended particles, the better.

Examples of water-soluble polymer compounds include methylcellulose, hydroxyethylcellulose, sodium carboxymethylcellulose, polyvinyl alcohol, partially acetylated polyvinyl alcohol, etc. Among these, those with a relatively low degree of polymerization are better; The viscosity of the aqueous solution is 100 centipoise or less, preferably 5
The optimum value is 0 centipoise or less.

The above-mentioned water-soluble polymer compound is added to 0.1% of the suspending agent in order to maintain appropriate viscosity and preferable thixotropy in the suspending agent.
By containing the suspension by weight of 5 to 5%, it is possible to maintain the viscosity of the suspension at 20° C. in the range of 200 to 2000 centipoise, preferably 300 to 1500 centipoise, for a long period of time.

If the viscosity of the suspending agent is less than 200 centipoise, it may not be possible to accurately prevent the deterioration of physical properties that occur during storage, especially the formation of hard caking, and if the viscosity is more than 2000 centipoise, it may be difficult to handle the suspension. This causes the product value to decrease.

The poorly water-soluble solid agricultural chemicals applicable to the aqueous suspension of the present invention are particularly limited as long as they have a melting point of 50°C or higher and a solubility in water of 500°C or less at 25°C. For example, 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (Linuron)
-N-tetrachloroethylthio-4-cyclohexene-
1,2-dicarboximide (difortan); methyl-2-benzimidazole carbamate; 2,4-dinitro-6-sec-butylphenyl dimethyl acrylate (binapacryl); 4,5,6.7-titrachlorophthalide ( 1-naphthyl-N-methyl carbamate (NAC); 2.4.6-trichlorophenyl-4'-nitrophenyl ether (CNP)
etc. can be mentioned.

The suspension agent contains 10 to 50% by weight of the above pesticide active ingredient,
Preferably it contains 20 to 40% by weight.

When preparing the aqueous suspension of the present invention, nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, sodium laurylbenzenesulfonate, sodium dialkylsulfosuccinate, etc. are used for the purpose of wetting and dispersion. Anionic surfactants such as sodium and calcium lignin sulfonates, sulfonate salts of naphthalene-formaldehyde condensates, etc. are used in amounts ranging from 0.101 to 10.0 by weight of the suspending agent.

Furthermore, ethylene glycol, diethylene glycol, or an inorganic salt such as ammonium sulfate, ammonium chloride, or sodium sulfate may be added to the suspending agent as an antifreeze agent.
It can also be contained in an amount of 10% by weight.

The production of the aqueous pesticide suspension of the present invention is extremely simple;
Manufactured using any of the following common methods:

(1) Solid pesticides and resins are pulverized in advance using a dry pulverizer, and then suspended in an aqueous dispersion medium.

(2) After the solid pesticide is pulverized in advance using a dry pulverizer, the resin is suspended in an aqueous dispersion medium and added to the wet pulverized product.

(3) After suspending the solid pesticide and resin in an aqueous dispersion medium, they are pulverized using a wet pulverizer.

For carrying out the present invention, methods (2) and (3) that allow the resin to be finely pulverized to several microns or less are preferred.

The present invention will be further explained below with reference to Examples, Reference Examples, and Test Examples.

(In the text, all parts simply refer to parts by weight.

) The viscosity was measured according to the following description.

Rotational viscometer Ni Tokyo Keiki Seisakusho BL type, No. 2 rotor measurement temperature = 20°C Measurement method: Attach the sample to the rotational viscometer, lower the crank lever and rotate at 60 rpm for 30 seconds, then increase the rotation speed to 3 Orpm. After rotating for another 10 seconds, the crank lever was raised to activate the viscometer, and the value was measured after 2 minutes.

Example 1 Binapacryl 33.0 parts Calcium ligninsulfonate 6.0 parts Ethylene glycol 6.0 parts Ester gum (
AA-L) 1.0 part Celogen 7 A
1.7 parts water
52.3 parts of binapacryl, calcium lignin sulfonate, ethylene glycol, ester gum (AA-L) [Aurayo Forestry Chemical Industry Natural Resin Derivatives] and 35 parts of water were mixed to make a suspension, and the mixture was made into a suspension. - It was placed in a crushing tank (manufactured by Miike Seisakusho, Model MA-IS), and a stainless steel ball with a diameter of 4 mm was added as a crushing media, and the mixture was crushed at 180 rpm for 2 hours.

Add Seroken 7A (Daiichi Kogyo Seiyaku ■ trade name carboxymethylcellulose sodium salt) to the resulting suspension.

A solution prepared by dissolving a 2W/w% aqueous solution with a viscosity of 50 centipoise or less at 20°C in the remaining water was added and mixed again to obtain an aqueous suspension of binapacryl.

The viscosity of this product was 800 centipoise at 20°C, which decreased to 330 centipoise after 8 weeks at 40°C, but no bird caking was observed and good physical properties were maintained.

Example 2 The recipe was exactly the same as Example 1, except that 1.0 parts of ester gum was removed from the recipe of Example 1, and 1.0 part of Betrozin (≠80) [Mikata Petrochemical Industries ■Petroleum Resin] was added instead. An aqueous suspension of binapacryl was obtained in the same manner.

The viscosity of this product at 20°C was 750 centipoise.

Example 3 1.0 part of ester gum was removed from the formulation of Example 1, and instead, Coumaron resin (NG-4) (Nippon Steel Chemical Industry ■) was used.
An aqueous suspension of binapacryl was obtained in exactly the same manner as in Example 1, except that 0 part was added.

The viscosity of this product at 20°C was 700 centipoise.

Reference Example 1 An aqueous suspension of binapacryl was obtained in exactly the same manner as in Example 1 except that 1.0 part of ester gum was removed from the formulation of Example 1 and the same weight of water was added instead.

The viscosity of this product at 20°C was 740 centipoise.

Reference Example 2 An aqueous suspension of binapacryl was obtained in exactly the same manner as in Example 1, except that 1.2 parts of Seroken 7A was reduced from the formulation in Example 1 and the same weight of water was added instead.

The viscosity of this product at 20°C was 150 centipoise.

Test Example 1 Aqueous suspensions of Examples 1 to 3 according to the present invention and Reference Example 1
Or the aqueous suspension obtained in step 2 with an inner diameter of 4.5 degrees and a height of 8C
The mixture was added to a 1 rL cylinder to a height of 7 cm, covered with a polyethylene stopper, and left in a constant temperature room at 40° C. for 4 weeks.

The sedimentation volume ratio is calculated by dividing the sedimentation layer height (CTL) of the aqueous suspension by 7, and then shake the cylinder by hand to mix.
The property of the precipitated layer showing fluidity again was defined as reflow dispersibility.

The layer above the precipitate layer is a transparent aqueous dispersion medium layer.

Evaluation of reflow dispersibility was expressed based on the following criteria.

D: The aqueous suspension immediately exhibits fluidity just by shaking the cylinder lightly.

(c): It does not exhibit fluidity unless the cylinder is vigorously shaken.

(2) Example of strong hard caking at the bottom of Nijilinda 4 Difortan 31.0 parts Sodium ligninsulfonate 6.0 parts Ethylene glycol 6.0 parts Polyoxyethylene nonylphenyl ether 0.05 parts Hydroxyethyl cellulose i, 1o= c ester gum
3.0 parts water
52.85 parts Daiholukun, sodium lignin sulfonate, ethylene glycol, polyoxyethylene nonylphenyl ether, ester gum (
Hydroxyethyl cellulose (HEC-AL-15) (Fuji Chemical ■, 2
A solution prepared by dissolving a 2w/Vv aqueous solution with a viscosity of 50 centiboise or less at 0° C.] in the remaining water was added and mixed again to obtain an aqueous suspension of difortan.

The viscosity of this product at 20°C was 620 centipoise.

Example 5 NAC 31.0 parts Sodium ligninsulfonate 6.0 parts Ethylene glycol 6.0 parts Polyoxyethylene nonylphenyl ether 0.05 parts Hydroxyethyl cellulose 1. log ester gum
3.0 parts water
After dissolving 52.85 parts of sodium lignin sulfonate, ethylene glycol, and polyoxyethylene nonylphenyl ether in 35 parts of water, ester gum [above] was added, and the mixture was ground for 2 hours using a wet grinder according to Example 1. , A solution of hydroxyethyl cellulose [above] was added to NAC, which had been pulverized in advance with a jet mill, and the remaining water, and mixed.
An aqueous suspension of AC was obtained.

The viscosity of this product at 20°C was 689 centipoise.

Claims (1)

[Scope of Claims] A solid agricultural chemical having a melting point of 150°C or higher and a solubility in water of 500°C or lower at 25°C, and one or more of finely pulverized petroleum resin, coumaron resin, and ester gum. , an aqueous pesticide suspension containing a water-soluble polymer compound and having a viscosity at 20°C of 200 centipoise or more. 2. Solid agricultural chemicals constituting 10 to 50 weight percent of the suspending agent, and one or more of pulverized petroleum resin, coumaron resin, and ester gum constituting 0.1 to 10 weight percent of the suspending agent. , 20 constituting 0.1-5% by weight of the suspending agent.
The agricultural chemical aqueous suspension according to claim 1, which contains a water-soluble polymer compound whose viscosity in a two-weight aqueous solution at °C is 100 centipoise or less.