JPH02108603A - Oil-in-water suspension pesticide composition with good storage stability - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an oil-in-water suspension of agricultural chemicals, and more specifically, a composition that is in liquid or paste form at 0°C to around room temperature. The present invention relates to a method for producing an oil-in-water suspension composition of a hydrophobic pesticide that has good stability during long-term storage.

<Prior art and problems> The present invention allows hydrophobic pesticides that are in liquid or paste form at temperatures from 0°C to around room temperature to be used in the same way as emulsions without using organic solvents, and has long-term storage stability. This invention relates to a method for producing a favorable oil-in-water suspension agricultural chemical composition.

Conventionally, powders, granules, wettable powders, solutions, emulsions, flow agents, etc. have been used as formulations for agricultural chemicals. Among these, emulsions are generally manufactured by dissolving pesticides in organic solvents and adding emulsifiers, etc. Compared to other formulations, emulsions have the advantage of being highly biologically effective and fast-acting. However, on the other hand,
Because it contains organic solvents, it has a flash point and unpleasant odor, and
They tend to be highly toxic and irritating, and may even cause drug damage.

A powder formulation of a hydrophobic agricultural chemical that is liquid or paste-like at around 0°C to room temperature and does not use an organic solvent.

Wettable powders, granules, etc. are available, but they use large amounts of inorganic mineral carriers, have relatively low pesticide content, require complex processes such as crushing, mixing, granulation, drying, and sieving, and also require long-term storage. It has several drawbacks, such as solidification and caking, large drifting and scattering during application, and increased manufacturing cost.

In recent years, efforts have been made to improve these drawbacks of pesticide formulations that are liquid or paste at temperatures ranging from 0°C to room temperature.

Aqueous suspension formulations and solubilized formulations have been developed that use water as a base material without using organic solvents or inorganic mineral carriers.

These formulation technologies are formulations in which liquid or paste pesticides are suspended in a continuous phase of water as minute droplets of several microns or less, so minute pesticide particles may aggregate during long-term storage. , coalesce to form cream phase or oil phase (pesticides)
In addition, it is susceptible to chemical changes such as hydrolysis and oxidative decomposition of the 14 drug ingredients, resulting in a decrease in the content of pesticide ingredients, coloring, generation of unpleasant odors, caking, pH changes, etc. In many cases, it is an important technology to provide good storage stability during long-term storage.

Aqueous emulsions (microemulsions) contain approximately 30% or less of hydrophobic pesticides in liquid or paste form, and contain relatively large amounts of emulsifiers consisting of nonionic surfactants and anionic surfactants with high solubilizing performance. (Generally, 1.5 to 2 times the amount of agricultural chemical ingredient content is required) is a preparation that makes agricultural chemicals transparent and solubilized with a size of 0.1 micron or less (for example, Japanese Patent Publication No. 46-20520 Publication No. 13696, Special Publication No. 53-13696, Special Publication No. 5g-17
721, JP 58-29761, JP 60-54928, JP 49-54547, JP 51-41437, JP 52-12
2826, JP 52-122628, JP 54-23123, JP 55-31056
Publication No. 132907/1983, Japanese Patent Application Laid-Open No. 1983-132907
On the other hand, as a technique for stabilizing liquid or pasty hydrophobic pesticides by dispersing and suspending them in water as relatively large particles of about 1 to 100 microns, A technology has been developed that uses a high-speed dispersion machine to disperse particles, and its thickening effect prevents agglomeration and coalescence of the dispersed particles, thereby imparting storage stability.

(For example, JP-A-53-99302, JP-A-55
-17301, JP-A-55-124707, and JP-A-55-124708.

JP-A-55-129201, JP-A-55-130
901, JP 56-49303, JP 56-49307, JP 56-120608, JP 58-11850f, JP 58-
Publication No. 128301.

JP-A-58-162503, JP-A-58-192
810, JP 59-39810, JP 61-37707, JP 61-180701) The key points of these technologies are PVA and gum arabic.

CMC, HEC, MC, guar gum, sodium alginate,
Use 1 to 10% of water-soluble polymers such as carrageenan, gelatin, carboxy starch, cellulose sulfate derivatives, polyacrylate, polymethyl methacrylate, PEG, albumin, etc. as a thickener, and if necessary, - boat fishing. It contains nonionic surfactants, anionic surfactants, inorganic salts, urea, etc. Among these water-soluble polymers, PVA and gum arabic are particularly useful.

However, the above formulation techniques have several problems. In other words, aqueous emulsions (microemulsions) have a small content of agricultural chemicals (approximately 30% or less), use a large amount of emulsifier, and during long-term storage, the initially transparent solubilized state becomes cloudy. In many cases, a precipitate is formed.

In addition, formulations that mainly use water-soluble polymeric substances as suspension stabilizers have a small pesticide component content of about 40% or less and a high viscosity of about 500 to 2000 centiboise, making them inconvenient during production and handling. Other disadvantages include residual adhesion to the container and difficulty in dispersing and diluting when preparing the spray solution. Furthermore, since the dispersed particles of the suspended medicinal ingredient are as large as 5 to 100 microns, there is a tendency for the suspension stability in the spray liquid to be insufficient and the biological effect to be reduced.

<Means for Solving the Problems> The present inventors have solved the above-mentioned drawbacks of oil-in-water suspension compositions based on conventional techniques for hydrophobic pesticides that are liquid or paste-like at temperatures ranging from 0°C to around room temperature. We are conducting extensive research into techniques for producing a new oil-in-water suspension composition that can be used almost in the same way as emulsions and has excellent chemical and physical storage stability over long periods of time. As a result of these efforts, the present invention has been completed.

That is, the agricultural chemicals targeted by the present invention are liquid or paste-like at temperatures ranging from 0°C to room temperature, and have low solubility in water (20°C).
is approximately 5. It is a poorly soluble or insoluble hydrophobic pesticide with an OOO ppm or less.

The present invention (1) prepares a hydrophobic I4 drug that is in liquid or paste form at around 0°C to room temperature by blending one or more surfactants represented by the following formula (1). Characteristic oil-in-water suspension pesticide composition.

12, R is a polyol residue having 3 to 9 carbon atoms, and m is 10 to 150 in total. n is 6 to 150 in total, and p is 3
Indicates an integer of ~6.

(2) A block obtained by adding propylene oxide to polyoxyethylene alkylphenyl ether, polyoxyethylene styryl (or benzyl) phenyl (or phenylphenyl) ether and diol having an HLB of 10 to 18, and then adding ethylene oxide. The oil-in-water suspension agricultural chemical composition described in item 1 is characterized in that it contains one or more polymeric surfactants.

The compound represented by the formula (1) is prepared by first adding propylene oxide to the starting material polyol under an alkali catalyst.
It can be easily synthesized by reacting under pressurized conditions at o-150°C and 2 to 1 Okg/cnf O), followed by the subsequent addition of ethylene oxide and final neutralization. The starting material is a polyol having 3 to 9 carbon atoms, such as glycerin, diglycerin, triglycerin, pentaerythritol, trimethylolpropane, sorbitol, sorbitan, glucose, and the like.

The appropriate number of moles of propylene oxide to be added is to-150, preferably in the range of 20 to 130.

The number of moles of ethylene oxide added next is 3 to 150.
is appropriate, but preferably in the range of 10 to 100.

These surfactants represented by formula (1) are generally HLB
Although the number ranges from 2 to 15, one or more of them can be selected and blended to produce a desirable effect.

In order to assist the emulsifying effect and emulsion stabilizing effect of the surfactant represented by formula (1), HLB is 10-1.
8, a type of propylene oxide-ethylene oxide block polymer starting from polyoxyethylene alkyl (generally octyl-dodecyl) phenyl ether, polyoxyethylene styryl (or benzyl) phenyl (or phenylphenyl) ether and diol. or 2
More than one species can be used together. The selection and formulation of these surfactants must be determined with due consideration to the type and physicochemical properties of the target hydrophobic pesticide, content in the composition, storage conditions, etc. In order to further enhance the storage stability of the oil-in-water type suspension agricultural chemical composition according to the pond water invention, anionic surfactants, nonionic surfactants, thickeners (water-soluble polymeric substances), specific gravity There is no problem in adding a regulator, a decomposition inhibitor, a pH adjuster (buffer), an anti-icing agent, an anti-caking agent, an antifoaming agent, a preservative, etc.

Examples of anionic surfactants include alkylbenzene sulfonates, alkyl sulfates, alkylnaphthalene sulfonates, dialkyl sulfosuccinates, naphthalene sulfonate-formalin condensates, lignin sulfonates, N-methyl-N-fatty acid amide taurine, polyoxyethylene alkyl ether sulfates, or phosphatides. phate, polyoxyethylene alkylphenyl ether sulfate or phosphate, polyoxyethylene styryl (or benzylphenyl) (or phenylphenyl) ether sulfate or phosphate, and the like.

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

In addition, if necessary, a small amount of a water-soluble polymer substance (thickener), which has conventionally been used as a stabilizer for oil-in-water type suspension agricultural chemical compositions, may be used in combination to obtain favorable results. For example, PVA, CMC, HEC.

MC, gum arabic, xanthan gum, guar gum.

Examples include sodium alginate, carrageenan, gelatin, carboxy starch, polyacrylate, polymethyl methacrylate, and PEG.

Specific gravity adjusters are sometimes used for the purpose of increasing stability by reducing the difference in specific gravity between pesticides in the form of suspended fine particles and the aqueous phase in the continuous phase.1For example, machine oil, spindle oil, etc.
Mineral oils such as paraffin oil and naphthenic oil, salt, potassium chloride, and calcium chloride.

Examples include magnesium chloride.

The anti-icing agent is a suspension agricultural chemical composition whose storage conditions are below 0°C1.
For example, when the temperature is -5°C or -10°C, it is used to prevent the water layer from freezing, and anti-icing agents are effective for boat fishing.

If pesticide components are chemically unstable and may cause hydrolysis or oxidative decomposition, use anti-decomposition agents (epoxy compounds,
It may be useful to adjust the pH to the pesticide stabilization range by adding epoxy vegetable oils, lactones, antioxidants such as BHT or hydroxyanisole, or by adding buffers to the aqueous layer. Many of them can be incorporated into the present invention without causing any problems.

In addition, antifoaming agents are added to prevent foaming when manufacturing or applying the wA cloudy agricultural chemical composition, and preservatives are added when it is necessary to prevent microbial contamination during storage. That is useful.

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

Liquid or paste pesticide 20-70% at θ℃~room temperature
(Weight) Surfactant represented by formula (1) in Claim 1 1-10 Claim 2
Nonionic surfactant O~5 Thickener (water-soluble polymeric substance) O~5 Decomposition inhibitor and buffering agent 0~5 Anti-icing agent
θ～5 Specific gravity adjuster, antifoaming agent, preservative, etc.
0-5 water
The remainder of the agricultural chemicals that are the object of the present invention are in liquid or paste form at θ°C to around room temperature. As long as they are insoluble or poorly soluble in water, they can contain insecticides, fungicides, herbicides, plant preparations, and the like.

In insecticides, 0.0-dimethyl-3-methyl-4 nitrophenyl phosphorothioate (fenitrothion), 0.
．． 0-dimethyl-3-methyl-4-methylthiophenylphosphorothioate (fenthion), 0.0-diethyl-2-isopropyl-4methyl-6-pyrimidinylphosphothioate (diazinon), 0,0-dimethyl-
3-[α-(Ethoxycarbonyl)benzyl cophosphorodithioate (Elsan), 0-see butylphenylmethyl carbamate (BPMC), 0-ethyl-8-propyl 2.4-dichlorophenylphosphorothiorothioate (Prothiophos) , etc., as well as 3-allyl-2-methylcyclobent-2-en-4-one-1-yl chrysansemate (allethrin), 5-(benzyl-3-furylmethyl) chrysansemate (resmethrin), 5 -Propargyl-3-furylmethylchrysansemate (flamethrin), 3-phenoxybenzylchrysansemate (phenothrin), 3-phenoxybenzyl-2,2-
Dimethyl-3-(β,β-dichloro)vinylcyclopropanecarboxylate (permethrin), α-cyano-
3-phenoxybenzyl-cis, trans-3-(2,
Synthetic pyrethroid pesticides such as 2-dichlorovinyl)-2,2-dimethyl-cyclopropanecarboxylate (cypermethrin) are used as fungicides, such as methylarsenic bis(dodecyl sulfide) (malus) and 〇-ethyl-8. S-diphenyldithiophosphate (EDDP)
, 0,0-diisopropyl-8-benzylphosphorothioleh (IBP), 5-methoxy-3-trichloromethyl-1,2,4-thiadiazole (ecromezole), and in herbicides, 5-p-chlorobenzyl Diethylthiocarbamate (benthiocarb), 5-(2-chlorobenzyl)-N,N-diethylthiocarbamate (orthobencarb), α-chloro-26'-diethyl-N-(
n-butoxymethyl)acetanilide (butachlor)
, α-chloro-2'6'-diethyl-N-(n-propoxyethyl)acetanilide (pretilachlor), S
-Ethylhexahydro-IH-azepine-1-carbothioate (molinate), S-ethyl-N-cyclohexyl-N-ethylthiocarbamate (cycloate)
However, the gist of the present invention should not necessarily be limited to these pesticides.Among these pesticides, a technique similar to the present invention regarding butachlor has been disclosed in Japanese Patent Application Laid-open No. 58-1999.
162504, it uses a polyalkylene gellicol ether type nonionic surfactant shown in the following - Shipman as a surfactant, and the technical contents are different from the present invention. be understood. That is, JP-A-58-162504 describes the formula % where R is alkyl, aryl or alkylaryl, n is approximately equal to 1250 and m is approximately equal to 2200 to give an approximate molecular weight of 3500. ). The term "alkyl" as used herein refers to straight or branched alkyl having 1 to 5 carbon atoms. The term "aryl" refers to aromatic groups of 6 to 12 carbon atoms, such as phenyl or naphthyl. The term "alkylaryl" refers to an alkyl-substituted phenyl group (
Alkyl groups here refer to those which may be straight-chain or branched and may have from 1 to 20 carbon atoms. 〕(
[The quotation in brackets] is used as an emulsifier. Furthermore, JP-A-57-80306 and JP-A-58-
Publication No. 162505 describes a technique using a surfactant as a method for producing a concentrated emulsion of phenoxyalkane carboxylic acid ester. Among these, nonionic surfactants, especially fatty acid polyethylene glycol esters,
Polyethylene glycol ether of aliphatic alcohol or alkyl phenol and polyoxyethylene polyoxypropylene block polymer, alkali metal salt of unsaturated fatty acid tauride and fatty acid alkyl tauride and polyoxyethylene alkylaryl ether phosphate or polyoxy A technique for use in combination with ethylene fatty amine is described and is understood to be different from the present invention. In producing the oil-in-water type suspension agricultural chemical composition according to the present invention, a conventional high-speed emulsifying machine, such as a homomixer, a homoblender, a homogenizer, a colloid mill, a turbine-type emulsifying machine, or a gallin-type porous machine is used. etc. is sufficient. Normally, the operating conditions of these emulsifying machines are as follows: all the components of the composition are charged, the speed is 2000 to 20000 rpm (preferably 5000 to 15000 rpm), and the
It is sufficient to stir the mixture at high speed for 0 minutes, and no special method is required.

The oil-in-water type suspension agricultural chemical composition according to the present invention produced by such a method generally has a particle size of 1 micron or less, and does not have a cream layer or an oil layer even when stored for a long period of time at -5 to 40°C. It is stable without any separation (a small amount of aqueous layer separation may occur, but it becomes a homogeneous suspension with simple stirring), and the viscosity is about 800 cp.
The 0-water composition, which exhibits physical properties on the order of s or less, can not only be used as is for small-scale spraying, but also easily diluted with water to any desired concentration and exhibits a stable emulsified state, so it can be sprayed in the same way as conventional emulsions. be able to.

The hydrophobic a-drugs exemplified here are in liquid or paste form at 0 to 5°C, taking into account the normal storage conditions for agrochemical preparations in Japan, but in cases where there is no need to store them at low temperatures such as 0 to 5°C. The agricultural chemicals may be liquid or pasty at around the relevant storage temperature, and the gist of the present invention should not be limited to hydrophobic agricultural chemicals that are liquid or pasty at around 0 to 5°C.

The oil-in-water type suspension pesticide composition according to the present invention can contain up to 70% (by weight) of liquid or paste pesticides, and can maintain the pesticide ingredients in suspension even under severe storage conditions. Can be held stably.

This effect is mainly promoted by the surfactant represented by the formula (1) and also by the components used in combination as an auxiliary agent.Although the stabilization mechanism is not necessarily clear, The displayed surfactants have relatively high molecular weights ranging from several hundred to several thousand, with a molecular weight of 3.
It is a multi-ridged surfactant with 6 to 6 branches, and has a lipophilic propylene oxide block in the center.
Because it takes a dimensional solution structure, emulsification and emulsion stabilization effects (
(including thickening effect), which has an excellent effect of miniaturizing suspended particles and preventing aggregation and coalescence, and exhibits good storage stability at a lower viscosity than when using water-soluble polymer substances. it is conceivable that. Moreover, the nonionic surfactant of claim 2 has this effect.

It is thought that it exerts a cooperative effect. Furthermore, anionic surfactants, water-soluble polymer substances (thickeners) 1 decomposition inhibitors, buffers, specific gravity adjusters, etc. used in combination as necessary in the composition also act as supplementary agents. Become.

Embodiment Next, the technical content of the present invention will be further explained using an embodiment.

(1) Emulsifier Examples (a) Emulsifier ■: In formula (1), R is glycerin, and m is 50. Surfactant (b) Emulsifier ■ where n is 62 in total and p is 3: In formula (1), R is pentaerythritol and m is 50 in total
, n is 60. Surfactant (c) Emulsifier ■ where p is 4: In formula (1), R is sorbitan and m is 102. 30% surfactant (by weight, the same applies hereinafter) in which n is 20 in total and p is 4, R in formula (1) is diglycerin, and m is 20 in total
．． A mixture of 70% surfactants in which n is 130 in total and p is 4 (d) Emulsifier ■ Interface in which R in formula (1) is glycerin, m is 66 in total, n is 6 in total, and p is 3 Activator 50%9 In formula (1), R is diglycerin and m is 20. 50% mixture of surfactants in which n is 80 in total and p is 4 (e) Emulsifier ■: R in formula (1) is glycerin, m is 66 in total, n is 6 in total, and p is 3 Mixture of 50% surfactant: 50% polyoxyethylene nonylphenyl ether (HLB: 13) (2) Example of oil-in-water suspension agricultural chemical composition (a) Example 1: Nippon Seiki homogenizer (universal) type) was used. Pour 80 gr of fenitrothion, 8 gr of emulsifier and 5 gr of ethylene glycol into an emulsification container (stainless steel, 200a + I2), and after sufficiently dissolving, add 57 gr of water.
at room temperature and the number of revolutions is 10. Emulsification was performed at OOOrpm for 5 minutes. 150 gr of a suspension composition containing 55% (by weight) of fenitrothion 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 propylene glycol, 2 gr of epoxy linseed oil and 0.2 M
KH, PO, -0,2N NaOH buffer (pH=8
．． 0) Contains 44% diazinon using 73 gr. 150 gr of suspension composition was obtained.

(c) Example 3: Diazinon 97gr, emulsifier ■8gr, propylene gellicol 3gr, epoxy linseed oil 2gr, and 0.9gr.
2M KH5PO4-0,2N NaOH buffer (pH
= 8.0) 40 g r were used to obtain 150 gr of a suspension composition containing 65% diazinon.

(d) Example 4: 150 gr of a suspension composition containing 21% Cypermethrin using 31 gr of Cypermethrin, 10 gr of emulsifier (1), 6 gr of propylene glycol and 103 gr of water
I got it.

(e) Example 5 Fenitrothion 44gr, BPMC40gr, emulsifier ■7gr, ethylene glycol 5gr and McIlva
Using 52 gr of ine buffer (pH=4.5), 150 gr of a suspension composition containing 29% fenitrothion and 26% BPMC was obtained.

(f) Example 6: Elsan 82gr, emulsifier ■8gr, propylene glycol 4gr, epoxy linseed oil 2gr, and McT1va
ine buffer (1) H=5.0) 150 gr of suspension composition containing 55% Elsan using 53 gr
I got it.

(3) Test method (a) Preservation test method Example 1 Approximately 60 cm of a m-shaped composition was placed in a cylindrical white preservation plate with a screw stopper (bottom diameter 3,8 an x height 10 cXrl)
, 100-day date), then tightly capped, then leave at room temperature (20-20 days).
5°C) and 45°C for 30 days and 90 days.

(b) Appearance change During the above storage test, the presence or absence of cream layer, oil layer, and water layer was visually observed, and their volume % was read from the scale.

(c) Particle Size Measurement Example 5 microliters of the suspension composition was diluted in 1OOmQ of physiological saline (0.90% w/v saline),
The particle size distribution at 20°C was measured using a Coulter Counter (manufactured by Nippon Kaiki, Model ZB), and the average particle size was calculated.

(d) Viscosity measurement method Using about 1.2 ml of the suspension composition of Example, an E-type viscometer (VI 5CON I CED manufactured by Tokyo Keiki Co., Ltd.) was used.
The viscosity of IORPM was measured at 25° C. using a mold.

[Effects of the Invention] The results of Examples and Comparative Examples are summarized in a table. As is clear from the table, it is clear that the oil-in-water suspension agricultural chemical composition of the present invention exhibits excellent stability over time.

Patent applicant: Toho Chemical Industry Co., Ltd.

Claims (2)

[Claims] (1) A hydrophobic pesticide that is in liquid or paste form at around 0°C to room temperature is prepared by blending one or more surfactants represented by the following formula (1). , an oil-in-water suspension pesticide composition with good storage stability. ▲There are mathematical formulas, chemical formulas, tables, etc.▼-Formula (1) Here, R is a polyol residue having 3 to 9 carbon atoms, m is 10 to 150 in total, n is 6 to 150 in total, and p is Indicates an integer from 3 to 6. (2) After adding propylene oxide to polyoxyethylene alkyl phenyl ether, polyoxyethylene styryl (or benzyl) phenyl (or phenylphenyl) ether, and diols having an HLB of 10 to 18,
2. The oil-in-water suspension agricultural chemical composition according to item 1, which contains one or more block polymer type surfactants obtained by adding ethylene oxide.