JPH10109904A - Granular herbicide for rice paddies - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a herbicide for rice paddies which is improved in disintegration, spreadability and dispersibility in water by combining a herbicide that is solid and slightly soluble in water with a specific disintegration aid, a specific dispersion agent and a solid carrier. SOLUTION: This granular herbicide contains a herbicide component which is slightly soluble in water and is solid, a tripolyphosphate salt as a disintegration aid, an anionic surfactant of α-olefinsulfonate salt as a dispersion aid and a solid carrier. Sodium or potassium tripolyphosphate is used as a disintegration aid in an amount of about 0.5-5wt.%. The α-olefin sulfonate salt used as a dispersion aid is sodium, potassium or ammonium salt of an α-olefin of 14-18 carbon atoms and is used in an amount of 0.5-5wt.%. The component of the herbicide is preferably pyrazolate or caffenstrol. Together with this herbicide, a water-soluble and low-melting herbicide such as dimethametryn or pretilachlor may be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a herbicide for a paddy field which has improved disintegration, spreadability and dispersibility in water of a herbicide for a paddy field containing a poorly water-soluble solid herbicide component.

[0002]

2. Description of the Related Art Herbicide granules for paddy fields disintegrate in water when applied to paddy fields, and the herbicidal components are released by spreading and exhibit a medicinal effect. Granules are widely used because they can apply herbicides more labor-savingly than dusts and liquids.

In recent years, there has been a growing demand for labor-saving application of herbicides, and application of 1 kg of granules having a lower application rate than conventional 3 to 4 kg of granules per 10a has been studied. However, at low application rates, the number of grains per unit area decreases,
It is difficult to spread the herbicide component evenly throughout the paddy field. In addition, when a water-soluble low-melting-point herbicide component is added thereto, the disintegration in water deteriorates with the passage of time, which causes a problem that the efficacy is reduced or a chemical injury is caused.

In order to solve these problems, it is necessary to improve the disintegration of the granules, and a method of adding a special disintegration aid (JP-A-6-271403, JP-A-5-24)
6803, Japanese Patent Publication No. 7-23283) and a method using a fine mineral powder having a coarse particle size (Japanese Patent Application Laid-Open No. 6-263601).
And a method of improving the dispersibility by reducing the particle size (Japanese Patent Publication No. 7-23284).

[0005]

However, in these techniques, when a poorly water-soluble herbicide component is contained in a high concentration, the dispersion of the granules in water after disintegration becomes insufficient,
Furthermore, when containing a water-soluble low melting point herbicide component,
Over time, the disintegration of the granules deteriorates, and the poorly water-soluble herbicide component is insufficiently dispersed in water. Further, making the particle size small is disadvantageous because the preparation cost increases.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a herbicidal composition for paddy fields containing a poorly water-soluble and solid herbicide component, an anionic surfactant such as tripolyphosphate and α-olefin sulfonate, and a solid carrier. Agent.

In the present invention, a sodium or potassium salt of tripolyphosphoric acid is used as a disintegration aid, and the amount used is 0.5 to 5% by weight.

[0008] As a dispersing aid for the poorly water-soluble herbicide component, C
A sodium salt of an α-olefin sulfonic acid having _{14 to} C ₁₈ ,
A potassium salt or an ammonium salt is used, and its amount is 0.1 to 5% by weight. The use of the α-olefin sulfonate significantly improves the dispersion of the base material in water.

The solid carrier is used as a bulking agent, and includes mineral carriers (bentonite, kaolin, clay, diatomaceous earth, calcium carbonate, vermiculite, perlite, etc.) and water-soluble carriers (ammonium sulfate, lactose, sodium sulfate, sodium carbonate, etc.). Potassium chloride), vegetable carriers (starch, wood flour,
Flour, etc.) and synthetic carriers (hydrous silicon dioxide, etc.).

In addition to the above essential components, disintegration aids such as polyacrylates, binders such as dextrin, carboxymethylcellulose, hydroxypropylcellulose, polyvinyl alcohol, sodium dioctylsulfosuccinate, sodium lauryl sulfate, dodecylbenzenesulfone Other surfactants, such as sodium alkylaryl sulfonates, such as acids, may be used additionally.

The poorly water-soluble herbicide component used in the present invention has a water solubility of 10 ppm or less, and can contain, for example, 0.5 to 30% by weight of the herbicide components listed in Table 1, and is preferably pyrazolate. , Kafenstroll,
It is selected from Daimron, Mefenacet and Bromobutide.

[0012]

[Table 1]

[0013] The present invention also comprises a water-soluble low-melting herbicide component having a water solubility of 20 ppm or more and a melting point of 70 ° C or less, which is added to the poorly water-soluble herbicide component. The dispersibility in water can be remarkably improved without deterioration in disintegration in water. The water-soluble low-melting-point herbicide component used in the present invention may preferably contain 0.5 to 10% by weight of the herbicide components listed in Table 2.

[0014]

[Table 2]

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In order to produce the herbicide for paddy fields of the present invention, a poorly water-soluble herbicide component is used alone or in combination with a mineral carrier, and is finely pulverized using a jet-omizer, a pin mill or the like, or is subjected to dry pulverization. An activator is added and wet-milled with an attritor, a bead mill or the like to make the average particle size 10 μm or less, preferably 5 μm or less, and anionic surfactants such as tripolyphosphate and α-olefin sulfonate are added thereto. , An extender, a binder and the like are mixed, kneaded by adding water, extruded, granulated and dried. Further, if necessary, it is produced by adsorbing a solution of a water-soluble low-melting-point herbicide component to granules.

[0016]

Examples Granules of Formulation Example 1 1 Pyrazolate raw material 12 parts 2 Bromobutide raw material 6 parts 3 Dimethmethrin raw material 0.6 parts 4 Pretilachlor raw material 4.5 parts 5 Sodium tripolyphosphate 3 parts 6 α-olefin sulfonic acid Sodium 2 parts 7 Dextrin 2 parts 8 Perlite 10 parts 9 Bentonite 10 parts 10 Calcium carbonate 49.9 parts A part of 1 and 8 was mixed and pulverized with a jet oimizer (average particle size 2.5 μm). Parts 2 and 10 were mixed and pulverized with an atomizer. These were mixed with 5, 6, 7, 9 and the remaining 8 and 10, and 22 parts of water was added and kneaded. The kneaded material was granulated with an extrusion granulator (0.8 mmφ). This was dried with a fluidized bed drier and sized to 0.5 to 1.4 mm to obtain base granules. Then, the solutions 3 and 4 were adsorbed on the base granules to obtain granules.

Granules of Formulation Example 1 1 pyrazolate drug substance 12 parts 2 bromobutide drug substance 6 parts 3 dimethamethrin drug substance 0.6 part 4 pretilachlor drug substance 4.5 parts 5 sodium dioctyl sulfosuccinate 0.2 part 6 sodium tripolyphosphate 5 parts 7 Sodium α-olefin sulfonate 2 parts 8 Dextrin 3 parts 9 Perlite 10 parts 10 Bentonite 25 parts 11 Calcium carbonate 31.7 parts 1, 5 and 7 parts of water were mixed and ground with an attritor (average particle size 2) 0.5 μm). Parts 2 and 11 were mixed and pulverized with an atomizer. These were mixed with 6, 7, 8, 9, 10 and the remaining 11, and 15 parts of water was added and kneaded. The kneaded material was granulated with an extrusion granulator (0.8 mmφ). This was dried in a fluidized bed drier and sized to 0.5 to 1.4 mm to obtain a base granule. The solutions 3 and 4 were adsorbed on the base granule to obtain granules.

Granules of Formulation Example 1 1 Caffeine sterol 2.1 part 2 Pyrazolate 12 part 3 Bromobutide 9 part 4 Dimethamethrin 0.6 part 5 Sodium dioctylsulfosuccinate 0.2 part 6 Nisseki Heisol SAS-296 5 parts 7 Sodium tripolyphosphate 5 parts 8 α-Olefin sodium sulfonate 2 parts 9 Dextrin 3 parts 10 Perlite 10 parts 11 Bentonite 25 parts 12 Calcium carbonate 26.1 parts 1 Finely pulverized raw material (average particle size 2) .2 μm), 2, 5 and water 7
Part of attritor pulverized product (average particle size 2.5 μm), and 3
And 12, some 7, 8, 9, 10, 11 and the remaining 12 were mixed with water,
After adding 5 parts and kneading, the kneaded material was extruded with a extrusion granulator (0.8
mmφ). This was dried with a fluid bed dryer, and then dried.
The grains were sized to 5 to 1.4 mm to obtain base grains. Next, the solutions 4 and 6 were adsorbed on the base particles to obtain granules.

Control granule 1 1 Pyrazolate drug substance 4 parts 2 Bromobutide drug substance 2 parts 3 Dimethamethrin drug substance 0.2 parts 4 Pretilachlor drug substance 1.5 parts 5 Sodium dioctyl sulfosuccinate 0.2 part 6 Sodium tripolyphosphate 2 Part 7 Dextrin 1.5 part 8 Bentonite 25 parts 9 Calcium carbonate 63.6 parts 1,5 and 2.5 parts of water were mixed and pulverized with an attritor (average particle size 2.5 μm). Parts 2 and 9 were mixed and pulverized with an atomizer. These, 6, 7, 8 and the remaining 9 were mixed and kneaded by adding 12 parts of water. The kneaded product was granulated by an extrusion granulator (0.7 mmφ). This was dried in a fluidized bed drier and sized to 0.5 to 1.4 mm to obtain a base granule. The solutions 3 and 4 were adsorbed on the base granule to obtain granules.

Control Granule 2 1 Caffeine sterol 2.1 part 2 Pyrazolate 12 part 3 Bromobutide 9 part 4 Dimethamethrin 0.6 part 5 Sodium dioctylsulfosuccinate 0.2 part 6 Nisseki Hisol SAS -296 5 parts 7 Sodium tripolyphosphate 5 parts 8 Dextrin 3 parts 9 Perlite 10 parts 10 Bentonite 25 parts 11 Calcium carbonate 28.1 parts 1 Finely ground raw material (average particle size 2.2 μm), 2, 5 and water 7
Part of attritor pulverized product (average particle size 2.5 μm), and 3
And 11 atomized pulverized products, and 7, 8,
9, 10 and the remaining 11 were mixed, 15 parts of water was added and kneaded, and the kneaded product was granulated with an extrusion-type granulator (0.8 mmφ). This was dried with a fluidized bed drier and then sized to 0.5 to 1.4 mm to obtain a base particle. Next, the solutions 4 and 6 were adsorbed on the base particles to obtain granules.

Test Example 1 Pyrazolate dissolution test 3 kg of soil was placed in a container having a surface area of 900 cm ² and a water depth of 4 cm.
Add water so that it becomes as follows. After standing for 24 hours, 90 mg (1 kg / 10a) of the granules of Formulation Examples 1 to 3 or 270 mg of the control granule 1 (3 kg / 10a, the active ingredient application rate per 10a is the same as in the formulation examples) After a predetermined time, the surface water at a position 1 cm below the water surface is collected, and the underwater DTP is collected.
The amount of [4- (2,4-dichlorobenzoyl) -1,3-dimethyl-5-hydroxypyrazole] was measured. The results are shown in FIG.

The granules of Formulation Examples 1 to 3 of the present invention showed pyrazolate elution equivalent to or higher than that of the control granule 1.

Test Example 2 Dissolution test of caffeine sterol 3 kg of soil was placed in a container having a surface area of 900 cm ² and a water depth of 4 cm
Add water so that it becomes as follows. After standing for 24 hours, 90 mg (1 kg / 10 a) of the granule of Formulation Example 3 or 90 mg (1 kg / 10 a) of the control granule 2 is applied, and after a predetermined time, the paddy water at a position 1 cm below the water surface is removed. Samples were taken and the amount of underwater cafentrol was measured. The results are shown in FIG.

The granule of Formulation Example 3 of the present invention showed elution of cafentrol equivalent to or higher than that of the control granule 2.

Test Example 3 Disintegration Spreading Test Approximately 50 ml of 10-degree hard water was placed in a petri dish having a diameter of 9 cm, three granules of Formulation Examples 1 to 3 were dropped, and the state of disintegration was observed until the original shape was not retained. Was measured and the area of expansion 30 minutes after dropping was measured. Table 3 shows the results.

[0026]

[Table 3]

[0027]

According to the present invention, even when a poorly water-soluble herbicide component is contained in a high concentration, the granules are sufficiently dispersed in water after disintegration, and the water-soluble low-melting-point herbicide is further obtained. Even when the herbicide component is contained, the disintegration of the granule does not deteriorate over time, and the poorly water-soluble herbicide component is sufficiently dispersed in water.

[Brief description of the drawings]

FIG. 1 shows the DTP elution curves of pyrarezoate-containing granules of Formulation Examples 1 to 3 in paddy water.

FIG. 2 shows a cafenstrol elution curve of a cafenstrol-containing granule of Formulation Example 3 in paddy water.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI A01N 43/40 101 A01N 43/40 101L 43/56 43/56 C 43/653 43/653 K 43/70 43/70 43/78 101 43 / 78 101 47/12 47/12 A 47/30 47/30 C

Claims (4)

[Claims] 1. A herbicide for a paddy field comprising a poorly water-soluble solid herbicide component, an anionic surfactant such as tripolyphosphate and α-olefin sulfonate, and a solid carrier. 2. The granule according to claim 1, wherein the poorly water-soluble solid herbicide component is selected from pyrazolate, cafenstrole, daimuron, mefenacet and bromobutide. 3. The granule according to claim 1, comprising a water-soluble low-melting-point herbicide component together with a hardly water-soluble and solid herbicide component. 4. The granule according to claim 3, wherein the water-soluble low-melting-point herbicide component is selected from dimethamethrin, pretilachlor, benfresate, dimepiperate, benthiocarb and butachlor.