JP2761902B2 - Oil-in-water suspension pesticide composition with good storage stability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to an oil-in-water type pesticide composition of a pesticide, and more specifically, is a liquid or paste at about 0 ° C. to near normal temperature. The present invention relates to a method for producing an oil-in-water suspension composition having good stability of a long-term storage of a hydrophobic pesticide.

<Conventional technology and problems> The present invention can use a hydrophobic pesticide in a liquid or paste state at around 0 ° C. to room temperature without using an organic solvent, like an emulsion, and has a long-term storage stability. The present invention relates to a method for producing a good oil-in-water suspension pesticide composition.

Conventionally, formulation forms of pesticides include powders, granules, wettable powders,
Solutions, emulsions, flow agents and the like have been used. Among them, emulsions are generally produced by dissolving a pesticide in an organic solvent and further adding an emulsifier and the like, but have advantages such as higher biological effect and quicker effect than other formulation types. On the other hand, since it contains an organic solvent, it has a flash point and an unpleasant odor,
In addition, toxicity and irritation tend to be strongly exhibited, and may cause phytotoxicity.

Dosage forms that do not use organic solvents of hydrophobic or pesticidal liquids or pastes near 0 ° C to room temperature include powders, wettable powders,
There are granules, etc., but a large amount of inorganic mineral carrier, relatively low pesticide content, complicated processes such as grinding, mixing, granulation, drying, sieving, and solidification and consolidation during long-term storage In addition to the above, there are some disadvantages, such as the occurrence of turbidity, large drift and scattering at the time of application, and an increase in manufacturing cost.

In order to improve such disadvantages of agrochemical formulations that are liquid or pasty at around 0 ° C. to room temperature, in recent years, water-based suspension formulations using water as a base material without using an organic solvent or an inorganic mineral carrier, and the like. Solubilized formulations have been developed.

These formulation techniques are formulations in which a liquid or paste-like pesticide is suspended as fine droplets of several microns or less in a continuous phase of water, so that fine pesticide particles aggregate during long-term storage, , Coalescence causes separation of the cream phase and oil phase (pesticide) to make it non-uniform, and is susceptible to chemical changes such as hydrolysis and oxidative decomposition of the pesticide component, lowering the content of the pesticide component, coloring In many cases, unpleasant odor is generated, consolidation, pH change, etc., and it is an important technique to impart good storage stability in long-term storage.

Aqueous emulsions (microemulsions) contain about 30% or less of liquid or pasty hydrophobic pesticides, and relatively large amounts of emulsifiers composed of nonionic surfactants and anionic surfactants with high solubilizing performance. (Generally, 1.5 to 2 times the amount of the pesticide component is required) to make the pesticide into a transparent solubilized state of 0.1 micron or less (for example, Japanese Patent Publication No. 46-20520, Kosho 5
No. 3-13696, Japanese Patent Publication No. 58-17721, Japanese Patent Publication No. 58-2
No. 9761, JP-B-60-54928, JP-A-49-54547
JP-A-51-41437, JP-A-52-122626, JP-A-52-122628, JP-A-54-23123, JP-A-55-31056, JP-A-60-132907, JP-A-60-1101) On the other hand, a technique for dispersing and suspending a liquid or pasty hydrophobic pesticide as relatively large particles of about 1 to 100 microns in water to stabilize it. For example, a technique has been developed in which a high-speed disperser is used to disperse in the presence of a water-soluble polymer to prevent the aggregation and coalescence of molecular particles by virtue of its thickening action, thereby imparting storage stability.

(For example, JP-A-53-99302, JP-A-55-17301
JP-A-55-124707, JP-A-55-124708, JP-A-55-129201, JP-A-55-130901, JP-A-56-493903, JP-A-56-49307, JP-A-56-120608, JP-A-58-118501, JP-A-58-128301, JP-A-58-162503, JP-A-58-192810 Gazette, JP-A-59-39810, JP-B-61-37707, JP-A-61-180701) The main points of these technologies are PVA, gum arabic, CMC, HE
C, MC, guar gum, sodium alginate, carrageenan,
Gelatin, carboxy starch, cellulose sulfate derivative, polyacrylate, polymethyl methacrylate,
Water-soluble polymers such as PEG and albumin are used as thickeners to
0% is used, and if necessary, general nonionic surfactants, anionic surfactants, inorganic salts, urea and the like are blended. Among these water-soluble polymers, PVA and gum arabic are particularly useful.

However, there are several problems with the above formulation technology. That is, aqueous emulsions (microemulsions) have a small content of pesticide components of at most about 30% or less, use large amounts of emulsifiers, and those that were initially in a transparent solubilized state during long-term storage become cloudy. Or a precipitate is often formed.

Formulations containing a water-soluble polymer as a suspension stabilizer are inconvenient during production and handling because the content of agrochemical components is as small as about 40% or less and the viscosity is as high as about 500 to 2,000 centipoise. In addition, there are problems such as residual adhesion to the container and difficulty in dispersing and diluting when adjusting the spray liquid. Furthermore, since the dispersed particles of the suspended pesticide components are coarse, having a size of 5 to 100 microns, there is a tendency that the suspension stability in the spray liquid is insufficient, the biological effect is reduced, and the like.

<Means for Solving the Problems> The present inventors have made the above-mentioned drawbacks of the oil-in-water suspension composition based on the prior art of the hydrophobic or pesticidal liquid or paste at 0 ° C. to around room temperature. , Which can be used in almost the same manner as emulsions, and which is chemically and physically stable for a long period of time. As a result of the superposition, the present invention has been completed.

That is, the pesticide targeted by the present invention is in a liquid or paste form at 0 ° C. to near normal temperature, and has a solubility in water (20 ° C.).
Is a poorly soluble or insoluble hydrophobic pesticide of about 5,000 ppm or less.

The present invention relates to a method for producing a liquid or paste-like hydrophobic pesticide at 0 ° C. to around room temperature by using one or two surfactants represented by the following formula (1).
An oil-in-water suspension pesticidal composition characterized by being prepared by blending at least one species.

Here, R is a polyol residue having 3 to 9 carbon atoms, m is an integer of 10 to 150, n is an integer of 6 to 150, and p is an integer of 3 to 6.

The compound represented by the above formula (1) is obtained by adding propylene oxide to a polyol as a starting material by first adding 100 parts of propylene oxide under an alkaline catalyst.
It can be easily synthesized by reacting at ~ 150 ° C under a pressurized condition of ^{2 to} 10 kg / cm ² , further adding ethylene oxide, and finally neutralizing. Starting materials are polyols having 3 to 9 carbon atoms, such as glycerin,
Examples include diglycerin, triglycerin, pentaerythritol, trimethylolpropane, sorbitol, sorbitan, glucose and the like.

The addition mole number of propylene oxide is suitably from 10 to 150, and preferably from 20 to 130. The number of moles of ethylene oxide to be added is suitably from 3 to 150, but preferably from 10 to 100.

The surfactants represented by the formula (1) are generally HLB
Although a wide range of about 2 to 15 is selected, one or two or more kinds are selected and blended, and a favorable effect is exhibited.

Emulsifying action of the surfactant represented by the formula (1),
And polyoxyethylene alkyl (generally octyl to dodecyl) phenyl ethers, polyoxyethylene styryl (or benzyl) phenyl (or phenylphenyl) ethers and diols having an HLB of 10 to 18 for the purpose of assisting the emulsion stabilizing action. Or a combination of two or more of propylene oxide-ethylene oxide block polymers starting from the above. The selection and blending of these surfactants must be determined in due consideration of the type and physicochemical properties of the target hydrophobic pesticide, the content in the composition, storage conditions, and the like. In addition, for the purpose of further assisting the storage stability of the oil-in-water suspension pesticide composition according to the present invention, an anionic surfactant, a nonionic surfactant, a thickener (a water-soluble polymer substance), Incorporation of a specific gravity adjusting agent, a decomposition inhibitor, a pH adjusting agent (buffer solution), an anti-freezing agent, an anti-caking agent, an antifoaming agent, an antiseptic, etc. can be used at all.

As anionic surfactants, for example, alkyl benzene sulfoneo, alkyl sulfate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, naphthalene sulfonate-formalin condensate, lignin sulfonate, N-methyl-N-fatty acid amido taurine,
Examples thereof include polyoxyethylene alkyl ether sulfate or phosphate, polyoxyethylene alkyl phenyl ether sulfate or phosphate, polyoxyethylene styryl (or benzylphenyl) (or phenylphenyl) ether sulfate or phosphate, and the like.

Examples of the nonionic surfactant include sorbitan alkylate, polyoxyethylene sorbitan alkylate, polyoxyethylene vegetable oil, and polyoxyethylene alkyl ether.

Further, if necessary, a favorable result may be obtained by using a small amount of a water-soluble polymer substance (thickener), which has been conventionally used as a stabilizer of an oil-in-water suspension pesticide composition,
For example, PVA, CMC, HEC, MC, gum arabic, xanthan gum, guar gum, sodium alginate, carrageenan, gelatin, carboxy starch, polyacrylate, polymethyl methacrylate, PEG and the like can be mentioned.

Specific gravity adjuster may be used for the purpose of increasing the stability by reducing the specific gravity difference between the pesticide suspended particles and the aqueous layer of the continuous phase, for example, machine oil, spindle oil, paraffin oil And mineral oils such as naphthenic oil, salt, potassium chloride, calcium chloride, magnesium chloride and the like.

The anti-icing agent is used for the purpose of preventing icing of the aqueous layer when the storage condition of the suspended pesticide composition is 0 ° C or less, for example, -5 ° C or -10 ° C, and the anti-icing agent is generally effective. It is.

If the pesticide component is chemically unstable and may cause hydrolysis or oxidative degradation, add an antioxidant (epoxy compound, epoxy vegetable oil, lactones, antioxidant such as BHT or hydroxyanisole, etc.) In addition, it is often useful to add a buffer to the aqueous layer to adjust the pH in the region where the pesticide is stabilized, and it is impossible to mix it with the present invention at all.

In addition, an antifoaming agent is used to prevent foaming when a suspended pesticide composition is manufactured or applied, and a preservative is added when it is necessary to prevent microbial contamination during storage. That is useful.

As described above, the preferred composition of the oil-in-water suspension pesticide composition according to the present invention is as follows, but the gist of the present invention should not be limited to this range.

20 to 70% (weight) of a liquid or pasty pesticide at about 0 ° C. to about room temperature Surfactant represented by the formula (1) of claim 1 1 to 10 Nonionicity of claim 2 Surfactant 5-5 Thickener (water-soluble polymer substance) 0-5 Decomposition inhibitor and buffer 0-5 Anti-freezing agent 0-5 Specific gravity adjuster, defoamer, preservative, etc. 0-5 Water residue Part The pesticide targeted by the present invention is in a liquid or paste form at 0 ° C. to near normal temperature. If it is insoluble or poorly soluble in water, it can contain insecticides, fungicides, herbicides, planting agents and the like.

Insecticides include 0,0-dimethyl-3-methyl-4-nitrophenyl phosphorothioate (fenitrothion),
0,0-dimethyl-3-methyl-4-methylthiophenyl phosphorothioate (fenthion), 0,0-diethyl-2-isopropyl-4methyl-6-pyrimidinylphosphothioate (diazinone), 0,0-dimethyl-S-
[Α- (ethoxycarbonyl) benzyl] phosphorodithioate (Elsan), 0-sec butylphenylmethyl carbamate (PBMC), 0-ethyl-S-propyl 2,4
-Dichlorophenyl phosphorothiolothioate (prothiophos), etc., 3-allyl-2-methylcyclopenta-2-en-4-one-1-ylchrysansemate (aresulin), 5- (benzyl-3- Furyl methyl)
Chrysansemate (resmethrin), 5-propargyl-3-furylmethylchrysansemate (flamesmeline), 3-phenoxybenzylchrysansemate (phenothrin), 3-phenoxybenzyl-2,2-dimethyl-3- (β, β Synthesis of -dichloro) vinylcyclopropanecarboxylate (permethrin), α-cyano-3-phenoxybenzyllusis, trans-3- (2,2-dichlorovinyl) -2,2-dimethyl-cyclopropanecarboxylate (cypermethrin) and the like Pyrethroid pesticides include fungicides such as methylarsenix bis (dodecyl sulfide) (Mars), 0-ethyl-S, S-diphenyldithiophosphate (EEDP), and 0,0-diisopropyl-S-benzyl phosphorothiolate ( IBP), 5
-Ethoxy-3-trichloromethyl-1,2,4-thiadiazole (echromezole), and in herbicides, Sp-
Chlorobenzyl diethylthiocarbamate (benthiocarb), S- (2-chlorobenzyl) -N, N-diethylthiocarbamate (orthovencarb), α-chloro-
2 ', 6'-diethyl-N- (n-butoxymethyl) acetanilide (butachlor), α-chloro-2', 6'-
Diethyl-N- (n-propoxyethyl) acetanilide (pretilachlor), S-ethylhexahydro-
1H-azepine-1-carbothioate (molinate),
Examples thereof include S-ethyl-N-cyclohexyl-N-ethylthiocarbamate (cycloate), but the gist of the present invention should not necessarily be limited to these pesticides. Among these pesticides, a technique similar to the present invention with respect to butachlor is described in JP-A-58-162504, but a polyalkylene glycol ether-based nonionic surfactant represented by the following general formula is used as a surfactant. It is understood that the technical contents are different from those of the present invention. That is, Japanese Patent Publication No. 58-162504 discloses the formula Where R is alkyl, aryl or alkylaryl, n is approximately equal to 1250 and m is the approximate molecular weight
About 2200 to be 3500). As used herein, the term "alkyl" refers to straight or branched chain alkyl having 1 to 5 carbons.
The term "aryl" refers to an aromatic group having 6 to 12 carbon atoms, for example, phenyl or naphthyl. The term "alkylaryl" refers to an alkyl-substituted phenyl group wherein the alkyl group can be straight or branched and
(Which may have 20 carbon atoms). ] (Quoted in []) is used as an emulsifier. Furthermore, JP-A-57-80306 and JP-A-58-162505 describe a technique using a surfactant as a method for producing a concentrated emulsion of phenoxyalkanecarboxylic acid ester. Among these, nonionic surfactants, in particular, aliphatic acid polyethynylene glycol esters, aliphatic alcohol glycerides or alkylphenol polyethylene glycol ethers and polyoxyethylene polyoxypropylene block polymers, unsaturated fatty acid taurides and It describes a technique in which an alkali metal salt of a fatty acid alkyl tauride and a polyoxyethylene alkyl aryl ether phosphate or a polyoxyethylene fatty amine are used in combination, which is understood to be different from the present invention.
In the production of the oil-in-water suspension pesticide composition according to the present invention, a normal high-speed emulsifier, such as a homomixer, a homoblender, a homogenizer, a colloid mill, and a turbine-type emulsifier or a Gaulin-type emulsifier can be sufficiently used. It is. Normally, the operating conditions of these emulsifiers are as follows: all components of the composition are charged,
High-speed stirring may be performed at a speed of 2000 to 20000 rpm (preferably 5000 to 15000 rpm) for 5 to 10 minutes, and no special method is required.

The oil-in-water suspension pesticidal composition according to the present invention produced by such a method generally has a particle size of 1 micron or less, and can be stored in a cream layer or an oil layer even during long-term storage at -5 to 40 ° C. Is stable without any separation of water (a small amount of aqueous layer may occur, but becomes a uniform suspension by simple stirring), and exhibits physical properties with a viscosity of about 800 cps or less. The present composition can be used not only for spraying a small amount as it is, but also easily diluted to an arbitrary concentration in water and shows a stable emulsified state, and can be sprayed like a conventional emulsion.

The hydrophobic pesticides exemplified here are in a liquid or paste form at 0 to 5 ° C. in consideration of the usual storage conditions for pesticide formulations in Japan, but when it is not necessary to store them at a low temperature such as 0 to 5 ° C. May be liquid or pasty at around the corresponding storage temperature, and the gist of the present invention should not be limited to hydrophobic or pesticidal liquid or paste at around 0 to 5 ° C.

The oil-in-water suspension pesticide composition according to the present invention can contain up to 70% (weight) of a liquid or pasty pesticide, and the pesticide component can be suspended even under severe storage conditions. It can be kept stable. This action is mainly based on the surfactant represented by the formula (1) and is further promoted by a component that is additionally used in combination. The stabilizing mechanism is not necessarily clear, but the formula (1) The displayed surfactant has a relatively high molecular weight of several hundreds to several thousands as a molecular weight, is a multi-chain type surfactant having three to six branches, and has a lipophilic propylene oxide block at the center. It has an emulsifying effect and an emulsifying stabilizing effect (including a thickening effect) because it has a three-dimensional solution structure, and has an excellent effect of preventing the suspension particles from being miniaturized and preventing aggregation and coalescence. It is considered that the composition exhibits low viscosity and good storage stability as compared with the case where a molecular substance is used. It is considered that the nonionic surfactant described in claim 2 has a cooperative effect on this effect. Furthermore, anionic surfactants, water-soluble polymer substances (thickeners), anti-decomposition agents, buffers, specific gravity adjusters, etc., which are used together as needed in the composition, also act as auxiliary substances. Become.

<Examples> Next, the technical contents of the present invention will be further described using examples.

(1) Example of emulsifier (a) Emulsifier: In the formula (1), R is glycerin, m is 50 as a whole, and n is a whole.
62, Surfactant with p = 3 (b) Emulsifier: R in the formula (1) is pentaerythritol, m is 5 in total
Surfactant in which 0 and n are 60 in total and p is 4 (c) Emulsifier: R in the formula (1) is sorbitan, m is 102 in total, n is 20 in total, and p is 4 30% (weight, the same applies hereinafter), R in the formula (1) is dichryserin, m is 20, n
Is a mixture of 70% of a surfactant having a total of 130 and p is 4. (d) Emulsifier A surfactant of the formula (1) in which R is glycerin, m is 66, n is 6, and p is 3. A mixture of 50%, a surfactant of 50%, wherein R of the formula (1) is diglycerin, m is a total of 20, n is a total of 80, and p is 4. (e) Emulsifier: R of the formula (1) is glycerin , M is 66 in total, n is 6 in total, and p is 3 50% surfactant: a mixture of 50% polyoxyethylene nonyl phenyl ether (HLB 13) (2) Oil-in-water suspension pesticide composition Examples of products (a) Example 1: A homogenizer (universal type) manufactured by Nippon Seiki was used. 80 gr of fenitrothion, 8 gr of emulsifier, and 5 gr of ethylene glycol were charged into an emulsification container (200 ml, made of stainless steel), and after sufficiently dissolving, 57 gr of water was added, followed by emulsification at room temperature at 10,000 rpm for 5 minutes. Fenitrothion 55
% (Same weight or less) was obtained. (The following examples used the same homogenizer and operating conditions.) (B) Example 2: 65 gr of diazinon, 7 gr of emulsifier, 5 gr of propyne glycol, 2 gr of epoxy linseed oil and 0.2 M KH ₂ PO ₄ −0.2
Using 73 gr of N NaOH buffer (pH = 8.0), diazinon 4
150 gr of a suspension composition containing 4% were obtained.

(C) Example 3: Daiajino 97Gr, emulsifiers 8Gr, propylene glycol 3GR, epoxy linseed oil 2gr and 0.2M KH ₂ PO ₄ -0.2N Na
Using 40 gr of OH buffer (pH = 8.0), 65% of diagemen
150 gr of a suspension composition containing

(D) Example 4: Cypermethrin 21 was prepared using 31 gr of cypermethrin, 10 gr of emulsifier, 6 gr of propylene glycol and 103 gr of water.
% Of a suspension-like composition containing 150% by weight.

(E) Example 5: 44 gr of fenitrothion, 40 gr of BPMC, 7 gr of emulsifier, 5 gr of ethylene glycol and McIuvaine buffer (pH = 4.5) 5
Using 2 gr, 150 gr of a suspension composition containing 29% of fenitrothion and 26% of BPMC was obtained.

(F) Example 6: Elsan 82gr, emulsifier 8gr, propylene glycol 4
gr, epoxy linseed oil 2 gr and McIlvaine buffer (pH = 5.
0) Using 53 gr, 150 gr of a suspension composition containing 55% of Elsan was obtained.

(3) Test method (a) Storage test method About 60 ml of the suspension composition of the example was placed in a cylindrical white storage bottle (bottom diameter 3.8 cm × height 10 cm, with 100 eyes) with a screw stopper, sealed, and then room temperature. (20-25 ℃) and 45 ℃ for 30 days and 90
Saved for days.

(B) Change in appearance During the preservation test, the presence or absence of a cream layer, an oil layer and an aqueous layer was visually observed, and the volume% was read from a scale.

(C) Particle size measurement method 5 microliters of the suspension composition of the example was diluted with 100 ml of physiological saline (0.90% w / v saline), and the solution was diluted using a Coulter counter (Model NB, manufactured by Nippon Kaiki). And 20
The average particle size was calculated by measuring the particle size distribution at ° C.

(D) Particle size measurement method About 1.2 ml of the suspension composition of the example was used at 25 ° C. and 10 RPM with an E-type viscometer (VISCONIC ED manufactured by Tokyo Keiki Co., Ltd.).
Was measured for viscosity.

[Effects of the Invention] The results of Examples and Comparative Examples are shown in a table. As is clear from the table, it is clear that the oil-in-water suspension pesticidal composition according to the present invention has excellent temporal stability.

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Claims (1)

(57) [Claims] 1. A liquid or paste-like hydrophobic pesticide at 0 ° C. to near normal temperature is prepared by blending one or more surfactants represented by the following formula (1). An oil-in-water suspension pesticide composition having good storage stability. Here, R represents a polyol residue having 3 to 9 carbon atoms, m represents an integer of 10 to 150, n represents an integer of 6 to 150, and p represents an integer of 3 to 6.