JPH0224801B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a granular agricultural chemical composition with good disintegration in water,
In particular, the present invention relates to a granular agricultural chemical composition that has good disintegration properties even in hard water. The dosage forms of agricultural chemicals used today include powders, emulsions, wettable powders, granules, and flowables. Among these, granules are easier to handle, and powders and wettable powders are easier to handle. Since there is no risk of fine powder or mist being scattered when sprayed, unlike emulsions, etc., it is highly evaluated for its safety, and its future development in the fields of herbicides and insecticides is expected. However, existing granules have drawbacks such as causing eutrophication of rivers, lakes and marshes, and their disintegration properties in water depend on the hardness of the water, and are particularly markedly reduced in hard water. That is, granular concentrates are mainly composed of agricultural chemicals, inorganic mineral carriers such as bentonite, calcium carbonate, clay, talc, and kaolin, and starch, polyvinyl alcohol,
Gelatin, binder such as sodium carboxymethylcellulose or sodium alginate, inorganic phosphates such as sodium tripolyphosphate and sodium pyrophosphate, polyethylene glycol nonyl phenyl ether (HLB12-14),
It is granulated by adding a disintegrant selected from surfactants such as sodium salt of dialkyl sulfosuccinate, sodium lignin sulfonate, or sodium alkylbenzene sulfonate. Among the above disintegrants, for example, phosphates Even if they are inexpensive, they have the disadvantage that if they flow into rivers or lakes, they tend to eutrophicate the water, resulting in various pollution problems. Additionally, surfactants have little effect on extremely hard water. In view of the above-mentioned drawbacks of known disintegrants, a polymer consisting of an unsaturated monocarboxylic acid and an unsaturated dicarboxylic acid, as already described in Japanese Patent Publication No. 48-1501, has been proposed as an improvement. . Although this latter improves disintegration in hard water compared to conventional disintegrants, it is still far from the level required today. The purpose of the present invention is to
By improving the shortcomings of known disintegrants for granular pesticides, and providing a composition for granular pesticides containing a new disintegrant that has good disintegration properties in hard water and does not cause eutrophication of water quality. be. As a result of numerous studies aimed at improving the drawbacks of the above-mentioned known disintegrants, the present inventors have recently discovered that a water-soluble salt of polystyrene sulfonic acid is used as a disintegrant for granular agricultural chemicals containing inorganic mineral substances as a carrier. We have discovered the fact that it has extremely excellent performance that is not easily affected by. The present invention is based on this knowledge, and its gist lies in the use of a water-soluble salt of polystyrene sulfonic acid as a disintegrant for granular agricultural chemicals. The water-soluble salt of polystyrene sulfonic acid, which is the main component of the composition of the present invention, can be obtained by, for example, sulfonating polystyrene with a sulfating agent such as chlorosulfonic acid in a halogenated solvent such as dichloroethane or methylene chloride, or by sulfonating polystyrene with a sulfating agent such as chlorosulfonic acid. Polystyrene sulfonic acid obtained by polymerizing an acid in water in the presence of a water-soluble synthesis initiator such as ammonium persulfate or hydrogen peroxide is added to sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonia, and monoethanol. Neutralization with an inorganic or organic base such as an amine, ethylenediamine or triethanolamine converts it into a water-soluble salt useful in the compositions of the invention. The composition of the present invention contains the above-mentioned disintegrant as an essential component in addition to the agricultural chemical raw material (powder or liquid) that is a necessary component as a granular agricultural chemical, the mineral powder and binder as the carrier. The amount of disintegrant is preferably selected at a ratio of about 0.2 to 3.0 (by weight) based on the total amount of the composition. However, this amount is only a rough guideline, and the expected delay in disintegration rate of the target granules,
Of course, the properties should be appropriately determined experimentally depending on the presence or absence of other disintegrants and other factors. Granulation of the agricultural chemical, which is the final form of the composition of the present invention, can be carried out in the same manner as general formulation methods, such as by rolling granulation in an inclined rotating pan, wet granulation such as extrusion using an extruder, or by slug tableting and crushing. It can be carried out by a dry granulation method or other known means. Dry granulation is generally preferable in order to prevent deterioration of the base ingredient, but in this case, it is recommended to add a small amount of lubricant such as stearic acid or magnesium stearate to the composition to prevent the composition from adhering to the die or punch. preferable. Hereinafter, embodiments of the invention will be described with reference to Examples, but the examples are of course for illustrative purposes and are not meant to limit the spirit of the invention. Example After adding water to the granular agricultural chemical compositions shown in the following formulations () and () and kneading them, they were granulated using an extrusion type granulator, and the water disintegration of the obtained granules was tested according to the following test method. Therefore, it was evaluated. The results are shown in Table-2. Formula () NIP bulk 9 (wt%) Bentonite 30 Calcium carbonate 59 Sodium carboxymethylcellulose 1 Disintegrant (see table-1 below) 1 Formula () NAC bulk 5 (wt%) Bentonite 50 Clay 43 Polyvinyl alcohol 1 Disintegrant 1

[Table] * Disintegrant of the present invention ** Control disintegrant (disintegration test method) Add standard hard water to a depth of 1 cm in a shear dish with a diameter of 25 cmφ and a depth of 4 cm. Next, hold the double-cut glass tube upright in the center of the shear plate and add 0.5% of the test granules.
Put g into a glass tube. Gently pull up the glass tube and measure the shortest and longest parts of the spread part of the granules every 5, 15, and 30 minutes, and use the average value as an index of the degree of disintegration. <Comprehensive evaluation> ◎: Excellent disintegration in water ○: Good △: Slightly poor ×: Very poor

[Table] As shown in the above table, the compositions of the present invention (Experiment No. 1 to
4) Even in the case of extremely hard water with a hardness of 20°,
Shows a similar disintegration index to less hard water. In contrast, the control composition (experiment no. 5-10)
The disintegration index of the former is clearly lower than that of the former, especially in Experiment No. using polyoxyethylene nonyl phenyl ether, sodium alkylbenzenesulfonate, and sodium ligninsulfonate as disintegrants.
A score of 8-10 is extremely poor. From the above results, it is clear that the water-soluble salt of polystyrene sulfonic acid according to the present invention is highly effective as a hard water-resistant disintegrant in improving the physical properties of granular agricultural chemicals.

Claims (1)

[Scope of Claims] 1. A granular agricultural chemical composition having excellent disintegration properties in water and containing a water-soluble salt of polystyrene sulfonic acid as an essential disintegrant component. 2. The composition according to claim 1, wherein the water-soluble salt of polystyrene sulfonic acid is contained within the range of 0.2 to 3.0% by weight. 3. The composition according to claim 1 or 2, wherein the composition comprises a mineral carrier.