JPH0364481B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a suspended agricultural chemical formulation having excellent suspension stability, fluidity and self-dispersibility. BACKGROUND ART Conventionally, agricultural chemicals have been formulated and used in the form of powders, emulsions, wettable powders, and the like. However, these have the following drawbacks. For example, powder agents scatter when sprayed and cause pollution. Furthermore, since emulsions use large amounts of organic solvents, they not only lead to air pollution but also go against resource conservation. Furthermore, since powders of wettable powders scatter when diluted with water, there is a safety problem for workers. Therefore, in order to improve these drawbacks, suspension preparations (flowable preparations) have been developed. Suspension preparations are stabilized suspension preparations by blending finely ground agricultural chemical ingredients with surfactants, water-soluble polymers, etc., and when used, they must be diluted with water in the same way as emulsions. It can be sprayed by hand and can be expected to have the same medicinal efficacy as emulsion. In addition, since suspension preparations contain almost no organic solvent, they have the advantage that, compared to emulsion preparations, there is no problem of chemical toxicity caused by solvents, and they are also safer in production, storage, and transportation. In this type of formulation, various methods have been tried to stabilize the drug substance in suspension. One method is to use a surfactant with a dispersing effect and a water-soluble polymer compound as a protective colloid in combination to appropriately increase the viscosity of the system and prevent separation and sedimentation of dispersed particles. Water-soluble polymer compounds used as protective colloids include gum arabic, sodium alginate, gum tragacanth, dextrin, gelatin, casein,
Glue, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, soluble starch, sodium polyacrylate, maleic anhydride.
Examples include styrene copolymer, water maleic acid-isobutylene copolymer, and the like. It is also known that xatan gum, which is a water-soluble biopolymer, is also used in suspension pesticide formulations. In order to obtain long-term stability in such pesticide suspension formulations, it is necessary to use a large amount of the above-mentioned polymer compounds to increase the viscosity of the system. In order to dilute a pesticide suspension preparation in water, a stirring device is required due to its poor self-dispersibility. Problems to be Solved by the Invention As described above, the present invention solves the problem of agricultural chemical suspension formulations, which had been considered difficult to handle because they required a large amount of high-molecular compounds to be added in order to obtain stable products. It is an object of the present invention to provide an easy-to-handle pesticide suspension formulation that is improved and has excellent suspension stability, fluidity, and self-dispersibility. Means for Solving the Problems As a result of intensive research, the present inventors have determined that a water-soluble pesticide having a carboxyl group has been added to a suspended agricultural chemical formulation containing a surfactant for stabilizing the suspension and a water-soluble biopolymer. The present invention has been achieved by discovering that the self-dispersibility can be significantly improved by incorporating a polyester polymer. The water-soluble biopolymer in the present invention is a fermented polysaccharide such as xanthan gum or rhamsan gum. Xanthan gum is produced by the microorganisms XANTHOMONAS and CAMPESTRIS fermenting glucose.
It is a natural gum substance made by refining the polysaccharides accumulated outside the bacterial cells and turning them into powder. The structure of xanthan gum is shown below, with the straight chain consisting of two glucose units, and the side chain consisting of two mannose units and one gluconic acid unit. M ⁺ represents Na, K or 1/2Ca. Ramsan gum also contains microorganisms ALCALIGENES
SPECIES, ATCC 31961 (AMERICAN TYPE
Registration No. in CULTURE COLLE CTION)
It is a natural gum substance made by fermenting glucose and refining the polysaccharides accumulated outside the bacterial cells and turning it into powder. Its chemical structure is shown below, with two main chains.
It consists of 1 glucose, 1 each of glucuronic acid and rhamnose, and 2 glucose as a side chain. M ⁺ represents Na, K or 1/2Ca. When the above-mentioned biopolymer is added in a very small amount to a pesticide suspension preparation, it exhibits remarkable thixotropy and is effective in stabilizing the suspension. The amount added is preferably 0.02 to 0.5% by weight, particularly 0.02 to 0.1% by weight. Next, as the surfactant used in the present invention,
Lignin sulfonate, alkylaryl sulfonate, dialkyl sulfosuccinate, polyoxyethylene alkyl allyl phosphate, polyoxyethylene alkyl allyl ether sulfate, alkylnaphthalene sulfonate, polyoxyethylene styryl phenyl ether sulfate, etc. anionic surfactants, polyoxyethylene alkyl allyl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkylate, polyoxyalkylene glycol, polyoxyethylene styryl Examples include, but are not limited to, nonionic surfactants such as phenol ether polymers. These may be used alone or in combination of two or more. In addition, water-soluble polymers having carboxyl groups that act as self-dispersion improvers in the present invention include carboxymethyl cellulose, carboxymethylated starch, polyacrylic acid, maleic anhydride-styrene copolymer, maleic anhydride-isobutylene copolymer, and so on. These include polymers and their salts. The above water-soluble polymer having a carboxyl group is
It exhibits an effect on the self-dispersibility of pesticide suspension preparations, and the amount added is 0.05 to 5% by weight, especially 0.1%.
Preferably it is 2% by weight. Note that preservatives, fragrances, dyes, etc. may be added to the product of the present invention. EXAMPLES Next, the present invention will be specifically explained using Examples, but the present invention is not limited to these Examples. In addition, parts and % in the examples indicate parts by weight and % by weight unless otherwise specified. Manufacturing method A of suspended agricultural chemicals Composition (I) Sulfur 50% Ethylene glycol 8% Surfactant 3% Water 39%-(x+y)% Biopolymer x% Self-dispersion improver y% 100% In a 500ml beaker, put the composition Add sulfur, ethylene glycol, surfactant and water of (I) and 200 parts of 0.8 mm glass beads per 100 parts of composition (I), and use a homodisper (manufactured by Nippon Tokushu Kika Co., Ltd.) at 200 rpm. 1
Stir for an hour, then add the biopolymer of composition (I) and a self-dispersion improver (a water-soluble polymer having a carboxyl group), stir and mix at 2000 rpm for 1 minute, and then filter to remove the glass beads. A suspended pesticide formulation is obtained. Examples 1 to 16 and Comparative Examples 1 to 10 The types and amounts of the biopolymer and self-dispersion improver (water-soluble polymer having a carboxyl group) in composition (I) were changed as shown in Table 1. A suspension of a pesticide formulation was obtained according to Production Method A, using polyoxyethylene distyrenated phenol ether (EO 13 mol) as a surfactant. Table 1 shows the results of testing the suspension stability and self-dispersibility of each suspended agricultural chemical formulation using the following methods. Stability evaluation method for formulations: Add 20 ml of the pesticide suspension to a 25 ml test tube with a stopper, leave it as it is, and test it at 10°C for 1 month and at 40°C for 1 month.
The stability over time was calculated using the following formula, and the larger the number, the worse the stability. Stability = Upper transparent separation layer (cm) / 20 x 100 Self-dispersion Add 100ml of 5° hard water to a 100ml graduated cylinder,
One drop of the suspended agricultural chemical formulation is dropped, and its self-dispersibility is visually judged. The display was performed as follows. ◎: Very good self-dispersion property ○: Good self-dispersion property △: Not completely dispersed and undispersed matter reaches the bottom of the cylinder ×: Not dispersed at all and all reaches the bottom

【table】

[Table] Examples 17 to 30 and Comparative Examples 11 to 15 The types and amounts of the biopolymer and self-dispersion improver (water-soluble polymer having a carboxyl group) of composition (I) are shown in Table 2. and polyoxyethylene (13.0 mol) distyrenated phenol ether sulfate as a surfactant.
A suspension of a pesticide formulation was obtained according to Process A above using ammonium. Table 2 shows the suspension stability and self-dispersibility test results for each suspended agricultural chemical formulation. Examples 31 to 40 and Comparative Examples 16 to 20 The types and amounts of the biopolymer and self-dispersion improver (water-soluble polymer having a carboxyl group) in composition (I) were changed as shown in Table 3. A suspension of a pesticide formulation was obtained according to the above-mentioned Production Method A, using polyoxyethylene (13.0 mol) distyrenated phenol ether phosphate as a surfactant. Table 3 shows the suspension stability and self-dispersion test results for each suspension drug formulation.

【table】

【table】

[Table] Effects of the Invention The suspension agricultural chemical formulation of the present invention can be manufactured by adding a small amount of a polymer compound, and becomes an easy-to-handle product with excellent fluidity, self-dispersibility, and stability.

Claims (1)

[Claims] 1. A water-insoluble or poorly soluble agricultural chemical ingredient is blended with a surfactant, a water-soluble biopolymer, and a water-soluble polymer having a carboxyl group to stabilize the suspension. It is made by suspending agricultural chemical ingredients in water, and the water-soluble polymers include carboxymethylcellulose, carboxymethylated starch, polyacrylic acid, maleic anhydride-styrene copolymer, maleic anhydride-isobutylene copolymer, and 0.02 to 0.5% by weight of the water-soluble biopolymer;
A suspension agricultural chemical formulation containing 0.05 to 5% by weight of the above water-soluble polymer.