Herbicidal aqueous suspension formulation

Abstract

To provide a herbicidal aqueous suspension formulation which is excellent in diffusivity of a herbicidal activity component into a paddy field when being used to a paddy field under flooding even after long term storage, capable of reducing a possibility of adhesion chemical injury to paddy field rice since the aqueous suspension formulation is hardly adhered to the paddy field rice, and reducing the adhesion chemical injury derived from the herbicidal activity component or the like even the aqueous suspension formulation is adhered to rice bodies.MEANS: There is provided a herbicidal aqueous suspension formulation for direct dispersion to a paddy field under flooding, the herbicidal aqueous suspension formulation being formed of a herbicidal activity component, butanediol modified polyvinyl alcohol, a surfactant and water.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an aqueous herbicidal suspension formulation which is unlikely to adhere to rice plants when sprayed and which has excellent diffusibility of the herbicidal active ingredient in paddy fields even after long-term storage. [Background technology]

[0002] Aqueous suspension formulations for direct application to flooded rice paddies are labor-saving because they can be applied without entering the paddy field, and because they are water-based, they are highly safe, so much research has been conducted and various formulations have been developed. Among these, the diffusibility of active ingredients in paddy fields and the adhesion of the drug to rice plants have a strong influence on herbicidal effects and phytotoxicity, so there has been a lot of research focused on these, as shown in the examples below.

[0003] Japanese Patent Application Laid-Open No. 2008-150316 (Patent Document 1) proposes an aqueous suspension formulation for direct application to flooded rice paddies, which consists of a herbicidal active ingredient, a sucrose fatty acid ester, an anionic surfactant and water, and is characterized by having a surface tension of 35 mN / m or less at 20°C.

[0004] Japanese Patent Laid-Open No. 2009-84180 (Patent Document 2) proposes an aqueous herbicide suspension composition for application on water surfaces, which contains a specific herbicidally active compound, a specific gravity regulator, a surfactant, a thickening component, an antifoaming agent and water, and is characterized in that the surfactants include an ionic surfactant and a nonionic surfactant having an HLB value of more than 15.

[0005] Japanese Patent Laid-Open No. 2002-293702 (Patent Document 3) proposes an aqueous suspension formulation for direct application to flooded paddy fields, which is characterized by comprising a herbicidal active ingredient having a solubility of 100 ppm or less in water at 20° C., modified polyvinyl alcohol, and water.

[0006] Japanese Patent Laid-Open No. 289502 / 1987 (Patent Document 4) proposes an aqueous herbicidal suspension formulation composition for post-transplanting treatment of flooded paddy fields, which contains a herbicidal active ingredient and a surfactant in water as a dispersion medium and has physical properties of a surface tension of 36 to 65 dyne / cm (25°C).

[0007] Japanese Patent Laid-Open No. 2009-269838 (Patent Document 5) proposes a herbicidal aqueous suspension formulation for direct application to flooded paddy fields, which comprises a herbicidal active ingredient, urea, a surfactant and / or a protective colloid, and water, and is characterized in that the formulation has a pH of 7.0 or higher and a formulation viscosity at 20°C in the range of 300 to 800 mPa s.

[0008] Japanese Patent Application Laid-Open No. 10-287503 (Patent Document 6) proposes an aqueous suspension formulation for direct application to flooded paddy fields, which contains a specific herbicidal active ingredient and is characterized by being composed of polyvinyl alcohol, a high boiling point solvent and water.

[0009] Japanese Patent Laid-Open No. 2004-26845 (Patent Document 7) proposes an aqueous suspension formulation for direct application to flooded rice paddies, which is characterized by comprising a herbicidal active ingredient having a solubility of 100 ppm or less in water at 20°C, a protective colloid (polyvinyl alcohol), and water.

[0010] The aqueous suspension formulations of Patent Documents 1 and 2 contain two types of surfactants, namely, "a sucrose fatty acid ester and an anionic surfactant" and "an ionic surfactant and a nonionic surfactant with an HLB value of more than 15," respectively, and thereby have excellent diffusibility of the herbicidal active ingredient. The aqueous suspension formulation of Patent Document 3 contains "modified polyvinyl alcohol," and thereby does not cause aggregation of dispersoids even when frozen during storage, and thus has excellent diffusibility.

[0011] On the other hand, the aqueous suspension formulations of Patent Documents 4 and 5 are inventions that reduce the damage caused by herbicidal active ingredients adhering to rice plants by, for example, "containing a surfactant and having a surface tension of 36 to 65 dyne / cm (25°C)" or "containing urea, a surfactant and / or a protective colloid".

[0012] In addition, the aqueous suspension formulation of Patent Document 6 is an invention that attempts to achieve both the dual benefits of diffusibility of the herbicidal active ingredient and reduction of phytotoxicity caused by adhesion to rice plants by containing "polyvinyl alcohol and a high boiling point solvent." Patent Document 7 is an invention that contains a protective colloid agent, thereby reducing phytotoxicity caused by the herbicidal active ingredient adhering to rice plants, providing excellent diffusibility of the herbicidal active ingredient, and preventing settling of dispersoids in the formulation over long-term storage.

[0013] However, even with these techniques, there is a problem in that the diffusibility of the herbicidal active ingredients in paddy fields decreases after long-term storage. Furthermore, as paddy fields become larger with the advancement of intensification, further improvement in diffusibility is required. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] JP 2008-150316 A [Patent Document 2] JP 2009-84180 A [Patent Document 3] JP 2002-293702 A [Patent Document 4] Japanese Patent Application Publication No. 62-289502 [Patent Document 5] JP 2009-269838 A [Patent Document 6] Japanese Patent Application Publication No. 10-287503 [Patent Document 7] JP 2004-26845 A Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention aims to solve the above problems by providing an aqueous herbicidal suspension formulation which, when applied to flooded paddy fields even after long-term storage, exhibits excellent diffusibility of herbicidal active ingredients in paddy fields, is unlikely to adhere to rice plants, and therefore is less likely to cause phytotoxicity due to adhesion to rice plants, and further, even if the aqueous suspension formulation does adhere to rice plants, reduces phytotoxicity due to adhesion caused by the herbicidal active ingredients, etc. [Means for solving the problem]

[0016] The present inventors have conducted extensive research to achieve the above-mentioned object, and as a result have found that the above-mentioned object can be achieved by an aqueous suspension formulation comprising a herbicidal active ingredient, butanediol-modified polyvinyl alcohol, a surfactant and water, thereby completing the present invention.

[0017] That is, the present invention is as follows: [1] to [3]. [1] An aqueous suspension formulation for direct application to flooded rice paddies, consisting of a herbicidal active ingredient, butanediol-modified polyvinyl alcohol, a surfactant and water. [2] The aqueous suspension formulation for direct application to flooded paddy fields according to [1], characterized in that the degree of saponification of the butanediol-modified polyvinyl alcohol is 70 mol% or more and less than 95 mol%. [3] An aqueous suspension formulation for direct application to flooded paddy fields according to [1] or [2], characterized in that the surfactant is a nonionic surfactant. Effect of the Invention

[0018] The aqueous suspension formulation of the present invention for direct spraying in flooded rice paddies allows the herbicidal active ingredient to diffuse well in paddy fields even after long-term storage, and shows excellent biological effects when sprayed simply from the ridges of the paddy field without entering the field.In addition, since the agent does not easily adhere to the rice field, there is little risk of damage due to adhesion, and even if the agent does adhere to the rice field, the damage caused by adhesion is reduced. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 shows paddy field test plots used in the diffusibility test of an aqueous herbicidal suspension formulation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The components constituting the aqueous suspension formulation for direct application to flooded paddy fields of the present invention and the method for preparing the formulation will be described in detail below.

[0021] <Components> (1) Herbicidal active ingredient The herbicidal active ingredient used in the present invention may be any ingredient generally used as an active ingredient in agricultural chemicals, and two or more kinds of herbicidal active ingredients may be used in combination.

[0022] Examples of such herbicidal active ingredients include phenoxy acids, carbamates, amides (such as butachlor and ipfencarbazone), ureas, acetolactic acid synthesis inhibiting herbicides (sulfonylurea and other acetolactic acid synthesis inhibiting herbicides), triazines (such as simetryn), diazines, pyrazoles, bipyridyliums, dinitroanilines, aromatic carboxylic acids, amino acids, nitriles, cyclohexanediones, phenylphthalimides, triketones, pyrimidyloxybenzoic acids, diazoles, fatty acids, organic phosphorus, cineoles, indandiones, benzofurans, triazolopyrimidines, oxazinones, aryltriazolinones, isourazoles, pyrimidinylthiophthalides, inorganic herbicides, and biological pesticides.

[0023] The specific herbicidal active ingredients contained therein are described in, for example, "Pesticide Handbook 2016 Edition" (published by Japan Plant Protection Association), "SHIBUYA INDEX 17th Edition" (published by SHIBUYA INDEX Research Group), and "The Pesticide Manual 18th Edition" (published by British Crop Protection Council).

[0024] Furthermore, as the herbicidal active ingredient used in the present invention, other known or future developed herbicidal active ingredients than those mentioned above can also be used.

[0025] The above herbicidal active ingredient is usually contained in an amount of 0.01 to 60 parts by weight, preferably 0.1 to 50 parts by weight, in 100 parts by weight of the aqueous suspension formulation.

[0026] (2) Butanediol-modified polyvinyl alcohol The butanediol-modified polyvinyl alcohol used in the present invention is a polyvinyl alcohol containing 1,2-diol in the side chain, and has low amorphousness and high hydrogen bonding strength compared to conventional polyvinyl alcohols. It is used as a film with excellent gas barrier properties and moldability, and has dispersing and emulsifying properties in aqueous solution.

[0027] In the present invention, the aqueous suspension formulation has the effect of dispersing the herbicidal active ingredient in the aqueous suspension formulation. In addition, when the aqueous suspension formulation is sprayed from the ridge, it has the function of diffusing the herbicidal active ingredient into the paddy field, and also has the characteristic of making it difficult for the herbicidal agent to adhere to the rice plant. Furthermore, since the contact angle is large when the aqueous suspension formulation is applied to the rice plant, it has the effect of reducing the phytotoxicity of the herbicidal active ingredient, which is caused by the adhesion of the herbicidal active ingredient to the rice plant.

[0028] The amount of butanediol-modified polyvinyl alcohol added is preferably 0.1 to 5.0 parts by weight per 100 parts by weight of the aqueous suspension formulation in view of the above effects and economic efficiency. From the viewpoint of the diffusibility of the herbicidal active ingredient in paddy fields, the saponification degree of butanediol-modified polyvinyl alcohol is preferably 70 mol% to less than 95 mol%.

[0029] (3) Surfactants The type of surfactant that can be used in the present invention is not particularly limited as long as it has the effect of dispersing the herbicidal active ingredient in the aqueous suspension formulation. Examples of surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants, and these surfactants may be used in combination.

[0030] Incidentally, when a surfactant such as a nonionic surfactant, an anionic surfactant or a cationic surfactant is contained in the formulation, there is a problem that the herbicidal agent adheres to rice plants during spraying, which may cause phytotoxicity. However, in the present invention, since the formulation contains butanediol-modified polyvinyl alcohol, it is possible to use a surfactant to improve the dispersibility of the herbicidal active ingredient.

[0031] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene styryl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan alkylate polyoxyethylene phenyl ether polymers, polyoxyethylene alkylene aryl phenyl ethers, polyoxyethylene alkylene glycols, polyoxyethylene polyoxypropylene block polymers, fluorine-based surfactants (such as perfluoroalkyl carboxylic acids), silicone-based surfactants (such as polyoxyalkylene dimethylpolysiloxane copolymers), and acetylene glycol-based surfactants (such as 2,4,7,9-tetramethyl-decyne-4,7-diol), but are not limited to these examples.

[0032] Examples of anionic surfactants include polycarboxylic acid surfactants, lignin sulfonates, alkylaryl sulfonates, dialkyl sulfosuccinates, polyoxyethylene alkylaryl ether sulfates, alkylnaphthalene sulfonates, polyoxyethylene styryl phenyl ether sulfates, alkylbenzene sulfonates, and alkyl sulfates, but are not limited to these examples.

[0033] Examples of cationic and amphoteric surfactants include, but are not limited to, alkylamine salts, quaternary ammonium salts, alkylbetaines, and amine oxides.

[0034] The amount of the above-mentioned surfactant to be added is preferably 0.1 to 30 parts by weight per 100 parts by weight of the aqueous suspension preparation, taking into consideration its effect and economic efficiency. From the viewpoint of diffusibility of the herbicidal active ingredient in paddy fields, nonionic surfactants are preferred, and polyoxyethylene styryl phenyl ether is the most preferred nonionic surfactant.

[0035] (4) Other ingredients In addition to the above-mentioned essential ingredients, the aqueous suspension formulation for direct application to flooded paddy fields of the present invention may contain auxiliary agents as required. Antifreezing agents such as ethylene glycol, propylene glycol, glycerin, thickening agents such as xanthan gum, guar gum, welan gum, carboxymethylcellulose, hydroxypropylcellulose, colloidal hydrated aluminum silicate, colloidal hydrated magnesium silicate, colloidal hydrated magnesium aluminum silicate, antifoaming agents such as silicone-based and fatty acid-based substances, antifungal agents such as potassium sorbate, p-chloro-metaxylenol, butyl p-oxybenzoate, 1,2-benzisothiazol-3(2H)-one, and antioxidants, ultraviolet inhibitors, crystal precipitation inhibitors, and the like may be added as stabilizers for the herbicidal active ingredients. The adjuvants that can be used in the present invention are not limited to the above examples.

[0036] <Preparation method of aqueous suspension formulation> The method for preparing the herbicidal aqueous suspension formulation of the present invention is not particularly limited, but it can be prepared, for example, by the following method. The herbicidal active ingredient, butanediol-modified polyvinyl alcohol, surfactant, water, and other auxiliary agents are added and mixed. If the herbicidal active ingredient is solid, it may be used after being finely pulverized in advance using a Jet pulverizer, or it may be prepared by adding and mixing the herbicidal active ingredient, butanediol-modified polyvinyl alcohol, surfactant, water, and other auxiliary agents, and then wet-pulverizing using glass beads, etc.

[0037] <Use of aqueous suspension formulation> The aqueous suspension formulation prepared as described above can be sprayed dropwise onto submerged paddy fields by shaking the container from the ridge without diluting the agent with water, sprayed onto submerged paddy fields from the ridge using a spray device, treated by placing the agent on the flow of inflowing water from a water inlet, attached to a rice transplanter and sprayed dropwise onto submerged paddy fields, sprayed dropwise onto submerged paddy fields from the air using a helicopter or drone, or sprayed using a radio-controlled boat.

[0038] The aqueous suspension formulation may be diluted with water 1.5 to 10 times and sprayed in the above manner. The amount of the aqueous suspension formulation of the present invention to be applied to flooded paddy fields is usually 0.1 to 3.0 liters, preferably 0.2 to 2.0 liters, and more preferably 0.3 to 1.0 liters per 10 ares. EXAMPLES

[0039] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Therefore, by replacing the herbicidal active ingredient, surfactant, etc. with various ones and preparing the same in the same manner as in the following examples, it is possible to obtain an aqueous suspension formulation for direct application to flooded paddy fields which has good diffusibility of the herbicidal active ingredient in paddy fields and reduces the phytotoxicity caused by adhesion of the herbicidal agent to rice plants. The examples were prepared based on the compositions shown in Table 1, and the comparative examples were prepared based on the compositions shown in Table 2. In the examples, all "parts" refer to parts by weight. The detailed production methods of aqueous suspension formulations of various pesticide active ingredients are as follows.

[0040] [Example 1] 5.0 parts of ipfencarbazone (herbicidal active ingredient), 1.5 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 0.3 parts of polyoxyethylene styrylphenyl ether were added to 93.0 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).Then, the mixture was wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0041] [Example 2] 5.0 parts of ipfencarbazone (herbicidal active ingredient), 1.5 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, 0.3 parts of polyoxyethylene styrylphenyl ether, and 1.0 parts of lignin sulfonate were added to 92.0 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).Then, the mixture was wet-pulverized using hard glass beads using a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0042] [Example 3] 5.0 parts of ipfencarbazone (herbicidal active ingredient), 1.5 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 1.0 part of lignin sulfonate were added to 92.3 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).Then, the mixture was wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0043] [Example 4] 5.0 parts of ipfencarbazone (herbicidal active ingredient), 1.5 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 0.2 parts of polyoxyethylene alkyl ether were added to 93.1 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0044] [Example 5] 5.0 parts of ipfencarbazone (herbicidal active ingredient), 1.5 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 98 mol%, and 0.3 parts of polyoxyethylene styrylphenyl ether were added to 93.0 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).Then, the mixture was wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0045] [Comparative Example 1 (based on Patent Document 7)] 5.0 parts of ipfencarbazone (herbicidal active ingredient) and 5.0 parts of polyvinyl alcohol (unmodified) were added to 89.8 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation.

[0046] [Comparative Example 2 (based on Patent Document 3)] 5.0 parts of ipfencarbazone (herbicidal active ingredient) and 8.0 parts of alkyl-terminated polyvinyl alcohol were added to 86.8 parts of water and mixed using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (Heidon Co., Ltd.) to obtain an aqueous suspension formulation.

[0047] [Comparative Example 3 (based on Patent Document 3)] 5.0 parts of ipfencarbazone (herbicidal active ingredient) and 5.0 parts of sulfonic acid-modified polyvinyl alcohol were added to 89.8 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by Heidon) to obtain an aqueous suspension formulation.

[0048] [Comparative Example 4] 5.0 parts of ipfencarbazone (herbicidal active ingredient) and 1.5 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol% were added to 93.3 parts of water and mixed using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (Heidon Co., Ltd.) to obtain an aqueous suspension formulation.

[0049] [Comparative Example 5] 5.0 parts of ipfencarbazone (herbicidal active ingredient) and 2.0 parts of polyoxyethylene styrylphenyl ether were added to 92.8 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added. The mixture was thoroughly stirred using a Three-One Motor (manufactured by Heidon) to obtain an aqueous suspension formulation.

[0050] [Comparative Example 6] 5.0 parts of ipfencarbazone (herbicidal active ingredient), 1.0 part of polyoxyethylene alkyl ether, and 2.0 parts of lignin sulfonate were added to 91.8 parts of water and mixed using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (Heidon Co., Ltd.) to obtain an aqueous suspension formulation.

[0051] [Example 6] 9.0 parts of simetryn (herbicidal active ingredient), 1.0 part of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 1.0 part of polycarboxylate were added to 88.8 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).Then, the mixture was wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred with a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0052] [Example 7] 9.0 parts of simetryn (herbicidal active ingredient), 1.5 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 0.5 parts of alkylbenzene sulfonate formalin condensate were added to 88.8 parts of water and mixed with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).Then, the mixture was wet-pulverized with hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of welan gum was added and thoroughly stirred with a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0053] [Example 8] 9.0 parts of simetryn (herbicidal active ingredient), 1.5 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 0.5 parts of polyoxyethylene styrylphenyl ether were added to 88.8 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).Then, the mixture was wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of welan gum was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0054] [Example 9] 9.0 parts of simetryn (herbicidal active ingredient), 2.0 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 0.2 parts of polyoxyethylene alkyl ether were added to 88.6 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0055] [Example 10] 9.0 parts of simetryn (herbicidal active ingredient), 0.5 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 0.3 parts of polyoxyethylene styrylphenyl ether were added to 89.9 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).Then, the mixture was wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.3 parts of colloidal hydrated aluminum silicate was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0056] [Comparative Example 7 (based on Patent Document 3)] 9.0 parts of simetryn (herbicidal active ingredient) and 8.0 parts of alkyl-terminated polyvinyl alcohol were added to 82.8 parts of water and mixed using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (Heidon Co., Ltd.) to obtain an aqueous suspension formulation.

[0057] [Comparative Example 8 (based on Patent Document 7)] 9.0 parts of simetryn (herbicidal active ingredient), 5.0 parts of polyvinyl alcohol (unmodified), and 0.3 parts of polyoxyethylene styryl phenyl ether were added to 85.5 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation.

[0058] [Comparative Example 9 (based on Patent Document 6)] 9.0 parts of simetryn (herbicidal active ingredient), 5.0 parts of polyvinyl alcohol (unmodified), and 10.0 parts of castor oil were added to 75.8 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred with a Three-One Motor (manufactured by Heidon) to obtain an aqueous suspension formulation.

[0059] [Comparative Example 10] 9.0 parts of simetryn (herbicidal active ingredient) and 1.0 part of polycarboxylate were added to 89.8 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by Heidon) to obtain an aqueous suspension formulation.

[0060] [Comparative Example 11] 9.0 parts of Simetryn (herbicidal active ingredient) and 1.0 part of alkylbenzene sulfonate formalin condensate were added to 89.8 parts of water and mixed using a TK Homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).Then, the mixture was wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of Welan gum was added and thoroughly stirred with a Three-One Motor (manufactured by Heidon) to obtain an aqueous suspension formulation.

[0061] [Comparative Example 12] 9.0 parts of simetryn (herbicidal active ingredient) and 1.0 part of polyoxyethylene alkyl ether were added to 89.8 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by Heidon) to obtain an aqueous suspension formulation.

[0062] [Example 11] 20.0 parts of butachlor (herbicidal active ingredient), 1.0 part of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 0.5 parts of polyoxyethylene styryl phenyl ether were added to 78.3 parts of water and mixed with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Then, 0.2 parts of xanthan gum was added and thoroughly stirred with a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0063] [Example 12] 20.0 parts of butachlor (herbicidal active ingredient), 1.0 part of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 0.5 parts of polyoxyethylene styrylphenyl ether were added to 78.2 parts of water, and mixed with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Then, 0.3 parts of colloidal hydrated magnesium silicate was added, and the mixture was thoroughly stirred with a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0064] [Example 13] 20.0 parts of butachlor (herbicidal active ingredient), 1.5 parts of butanediol-modified polyvinyl alcohol with a saponification degree of 89 mol%, and 1.0 parts of lignin sulfonate were added to 77.3 parts of water, and mixed with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Then, 0.2 parts of xanthan gum was added, and the mixture was thoroughly stirred with a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation of the present invention.

[0065] [Comparative Example 13] 20.0 parts of butachlor (herbicidal active ingredient) and 2.0 parts of polyoxyethylene alkyl ether were added to 77.7 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.3 parts of colloidal hydrated aluminum silicate was added and thoroughly stirred using a Three-One Motor (manufactured by Heidon) to obtain an aqueous suspension formulation.

[0066] [Comparative Example 14] 20.0 parts of butachlor (herbicidal active ingredient) and 1.0 part of lignin sulfonate were added to 78.8 parts of water and mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).The mixture was then wet-pulverized using hard glass beads in a Labostar Mini LMZ015 (manufactured by Ashizawa Finetech Co., Ltd.), and 0.2 parts of xanthan gum was added and thoroughly stirred using a Three-One Motor (manufactured by HEIDON) to obtain an aqueous suspension formulation.

[0067] [Table 1]

[0068] [Table 2]

[0069] The usefulness of the herbicidal aqueous suspension formulation of the present invention will be shown by the following test examples. The tests were carried out for the purpose of evaluating the adhesion to rice plants (adhesion condition, adhesion damage) and the diffusibility in paddy fields (immediately after production and after long-term storage).

[0070] [Test Example 1] Adhesion test 100cm 2 The pot was filled with paddy field soil, and two rice plants at the 1.5-1.8 leaf stage were transplanted, with two plants per plant, and the water depth was about 3 cm. Five days after transplanting the rice, 30 μL x 4 drops of the herbicidal aqueous suspension formulation of the Examples and Comparative Examples were applied to the center of the second leaf blade using a micropipette. The degree of adhesion of the herbicidal agent to the rice plant at this time was evaluated according to the following criteria. In addition, 30 μL of the herbicidal agent was forcibly applied to the second leaf blade of the rice plant using a micropipette, and after 14 days in a greenhouse (water temperature was about 15°C, which is a temperature at which herbicidal damage is likely to occur) after the herbicidal agent was applied, the degree of herbicidal damage caused by the adhesion, such as browning of the rice plant, was evaluated according to the following evaluation criteria. The results are shown in Table 3 (Examples) and Table 4 (Comparative Examples).

[0071] (Evaluation Criteria) Adhesion Test Adhesion level 0: No adhesion at all 1: Very slight adhesion 2: Slightly adherent 3: About half of it adheres 4: The entire amount adheres Drug damage level: None ±: Slight (no practical problem) +: Small (problems in practical use) ++: Medium (problems in practical use) +++: Large (problems in practical use)

[0072] [Test Example 2] Diffusion test during manufacturing and after long-term storage Each plot has an area of ​​16m 2 A paddy field test plot (2m x 8m) (5cm flooded) was created, and 8mL (equivalent to 500mL / 10a) of the herbicidal aqueous suspension formulations of the Examples and Comparative Examples was directly dropped at point A in Figure 1 from 1m below the water surface using a pipette. 24 hours after treatment, 20mL of water was collected from a depth of 5cm to the water surface at each of points A to E in Figure 1, and the concentration of the herbicidal active ingredient in the water was analyzed by HPLC. The aqueous suspension formulations after long-term storage were placed in a sealed container and left to stand in a thermostatic chamber at 40°C for 90 days. After that, they were left to stand at room temperature for one day before being used in a diffusibility test.

[0073] The water was collected using a glass tube with an inner diameter of 1 cm and a length of 8 cm, which was gently inserted into the paddy water to a depth of 5 cm, a rubber stopper was placed on the top of the glass tube, and it was gently pulled out to collect about 4 mL of paddy water. This procedure was repeated five times at the same spot to collect a total of 20 mL of water per spot. The diffusibility was expressed as a percentage of the theoretical water concentration when the herbicidal active ingredient is uniformly diffused in the water in the test plot, using the following formula.

[0074]

number

[0075] The results are shown in Tables 3 and 4.

[0076] [Table 3]

[0077] [Table 4]

[0078] Explanation of the table As can be seen from Tables 1 to 4, Examples 1 to 13, which contain butanediol-modified polyvinyl alcohol and a surfactant, showed excellent results with high practicality in terms of adhesion to rice plants (adhesion condition, chemical damage caused by adhesion) and diffusibility in paddy fields (immediately after production and after long-term storage). On the other hand, Comparative Examples 1 to 14, which do not contain either of these two, showed problematic results in one or more items. Comparative Examples 1 to 3 and 7 to 9, which were produced based on Patent Documents 3, 6, and 7, which contain modified polyvinyl alcohol other than butanediol-modified polyvinyl alcohol and unmodified polyvinyl alcohol, also showed problematic results in terms of adhesion to rice plants or diffusibility.

[0079] Among the Examples, Example 1, which used butanediol-modified polyvinyl alcohol with a saponification degree of 70 mol% or more and less than 95 mol%, showed improved diffusibility compared to Example 5, which used a saponification degree of 95 mol% or more. Also, Examples 1, 4, and 8 to 12, which used butanediol-modified polyvinyl alcohol with a saponification degree of 70 mol% to less than 95 mol% and only a nonionic surfactant as the surfactant, showed improved diffusibility compared to Examples 2, 3, 6, 7, and 13, which included an ionic surfactant.

[0080] From the above, in order to obtain a herbicidal aqueous suspension formulation in which the sprayed agent is less likely to adhere to rice plants and in which the herbicidal active ingredient has excellent diffusibility in paddy fields even after long-term storage, it was found that the inclusion of both butanediol-modified polyvinyl alcohol and a surfactant is an effective means. Furthermore, it was found that an even more effective means is for the butanediol-modified polyvinyl alcohol to have a saponification degree of 70 mol% or more but less than 95 mol%, and for the surfactant to be a nonionic surfactant.

Claims

1. 1. An aqueous suspension formulation for direct application to flooded paddy fields, comprising a herbicidal active ingredient, butanediol-modified polyvinyl alcohol, a surfactant and water, wherein the butanediol-modified polyvinyl alcohol has a degree of saponification of 70 mol % or more but less than 95 mol %.

2. 2. The aqueous suspension formulation for direct application to flooded paddy fields according to claim 1, characterized in that the surfactant is a nonionic surfactant.

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