WO2020233646A1 - Herbicidal composition containing microcapsules, preparation method therefor, and use thereof - Google Patents

Abstract

The present invention provides an herbicidal composition containing microcapsules. The herbicidal composition contains microencapsulated oxadiazon and an optional non-encapsulated second herbicidal active matter. The herbicidal composition is applied before planting crops or before crop emergence, and therefore, commercially acceptable weed control and commercially acceptable crop injury can be simultaneously given.

Description

Herbicidal composition containing microcapsules and preparation method and application thereof

cross reference

This application claims the priority of the Chinese patent application 201910425052.6 filed with the Chinese Patent Office on May 21, 2019 under the title of "A herbicidal composition containing microcapsules and its preparation method and use", the content of which is incorporated by reference in its entirety Incorporated into this article.

Technical field

The present invention relates to the field of pesticide formulations, in particular to a microcapsule herbicidal composition using a microencapsulation method to encapsulate oxadiazon and a preparation method thereof; the present invention also relates to the application of the herbicidal composition of the present invention to reduce damage to crop leaves Methods to damage and control weeds in crop fields.

Background technique

Oxadiazone is usually applied to the soil as a pre-emergence herbicide before planting. However, applying oxadiazon before crop germination has caused many crops to be damaged or killed. Even after the crop has germinated, but before the later germinated weeds germinate, the application of a commercially available oxadiazone-containing formulation still causes unexpected leaf damage to the crop. The phenomenon of crop damage was observed by using commercially available oxadiazon-containing emulsifiable concentrates, suspension concentrates or wettable powders. Especially under rainy or over-irrigation conditions, crop damage is more serious.

The microencapsulation process using the prior art including herbicidal active substances is effective in reducing the damage of herbicidal active substances to crops. However, those skilled in the art have a technical challenge to the optimal release rate to obtain acceptable biocontrol effects for a given activity while minimizing crop damage to a commercially acceptable level.

Therefore, there is a need for herbicide compositions and methods that utilize oxadiazon herbicidal actives to simultaneously obtain commercially acceptable weed control or commercially acceptable crop damage. There is a further need for oxadiazon-containing herbicide compositions and methods that can be applied to crops before emergence.

Summary of the invention

One object of the present invention is to provide a herbicidal composition containing oxadiazon, which can be applied to both commercially acceptable weed control and commercially acceptable weed control by applying the herbicidal composition before planting or crop emergence. Crop damage.

The present invention is realized by encapsulating oxadiazon in microcapsules. The oxadiazon encapsulated by the microcapsules is released from the microcapsules by molecular diffusion through the shell wall. The release rate of herbicide can be increased or decreased by changing the thickness of the shell wall.

However, when the thickness of the shell wall is too thin, the thin shell wall of the microcapsule will rupture prematurely during processing or field application, resulting in immediate release. In addition, storage stability due to shell wall defects may also occur. Some of the oxadiazone can crystallize outside the capsule, which will cause the problem of clogging of the spray nozzle. Moreover, when applied in the field, the safety of crops has not been improved due to the rapid release.

However, when the thickness of the shell wall increases, the biological control effect of the herbicidal active substance is reduced because of the delay of the release of the herbicidal active substance.

The present invention encapsulates oxadiazon in the microcapsules, through the selection of the solvent in the microcapsule, the ratio of the herbicidal active substance to the solvent in the microcapsule, the composition of the polymer shell wall material, and the weight of the capsule wall to the weight of the microcapsule. , Average microcapsule particle size and other factors, we have successfully prepared a herbicidal composition containing microencapsulated oxadiazone; and applying the herbicidal composition before planting the crop or before the crop emerges, it can be simultaneously given commercially acceptable Of weed control and commercially acceptable crop damage.

The microcapsules may also contain one or more solvents; and the weight ratio of the herbicidal active substance to the solvent in the microcapsules is 1:10-10:1, such as 1:10, 1:9, 1:8 , 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7 :1, 8:1, 9:1, 10:1, preferably 1:5-5:1, more preferably 1:2.5-2.5:1.

The one or more solvents contained in the microcapsules are selected from aromatic hydrocarbon solvents, isooctyl palmitate, methyl oleate, hydrogenated rosin, polymerized rosin, rosin esters or hydrogenated rosin, and polyhydroxy alcohol esters. It has been found that the addition of solvents in the microcapsules can change the solubility parameter characteristics of oxadiazon and increase or decrease the release rate of the active substance from the microcapsules.

In the microcapsule, the capsule wall is made of a porous polymer capsule wall material, and the polymer shell wall material is selected from polyurea, polyurethane, polyamide, polycarbonate, polysulfonamide, urea formaldehyde, melamine resin, melamine urea resin , Gelatin, gum arabic cross-linked and uncross-linked combination.

The preferred microcapsule wall material of the present invention may preferably contain polyurea; polyurea is a polyurea shell wall obtained by the reaction of polyisocyanate and polyamine. The polyamine has two or more amino groups per molecule; the polyisocyanate has two or more isocyanate groups per molecule. Preferably, when mechanical release (microcapsule rupture) is not required, the release of the herbicidal active substance is controlled by the capsule wall of the microcapsule.

Microcapsules can be prepared by encapsulating oxadiazon in the capsule wall. In the reaction medium, the polyamine component and the polyisocyanate component must react with the polyamine component and the polyisocyanate component to form the wall of the microcapsule by containing the concentration of the amine group in excess of the molar equivalent of the isocyanate group. The molar ratio of amine molar equivalent concentration to isocyanate molar equivalent concentration can be calculated according to the following equation:

Molar equivalent ratio = amine molar equivalent/polyisocyanate molar equivalent

In the above formula, the amine molar equivalent includes the sum of the amine molar equivalents of all polyamines in the reaction medium; the polyisocyanate equivalent includes the sum of the molar equivalents of all isocyanates in the reaction medium.

The polymer shell wall material is a polyurea shell wall obtained by reacting a polyisocyanate as a first wall forming component and a polyamine as a second wall forming component.

The preferred polyisocyanate as the first wall forming component can be selected from tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethylene-4,4' -Diisocyanate, polymethylene polyphenylene isocyanate, 2,4,4'diphenyl ether triisocyanate, 3,3'-dimethyl-4,4'-diphenyl diisocyanate, 3,3' -Dimethoxy-4,4'-diphenyl diisocyanate, 1,5-naphthylene diisocyanate and 4,4',4"-triphenylmethane triisocyanate. Preferred polyisocyanate first wall formation The component is toluene diisocyanate or polymethylene polyphenyl isocyanate.

The polyamine as the second wall forming component can be selected from ethylene diamine, 1,3-propane diamine, butane diamine, pentane diamine, hexamethylene diamine, diethylene triamine, triethylene tetramine, Pentaethylene hexaamine, 4,9-dioxazoldodecane-1,12-diamine, 1,3-phenylenediamine, 2,4- and 2,6-toluenediamine and 4,4' -Diaminodiphenylmethane or its acid addition salt.

The preferred polyamines of the present invention are selected from ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine.

The polyisocyanate is preferably polymethylene polyphenyl isocyanate, diphenylmethane isocyanate, polymethylene diphenyl isocyanate, and toluene diisocyanate.

The polyamine is preferably ethylenediamine, diethyltriamine, triethylenetetramine, 1,6-hexanediamine, triethylamine, and tetraethylenepentamine.

The ratio of the molar equivalent of amine contained in the polyamine to the molar equivalent of isocyanate contained in the polyisocyanate is at least 1.1:1.

The ratio of the molar equivalent of amine contained in the polyamine to the molar equivalent of isocyanate contained in the polyisocyanate is 1.15:1 to 1.3:1.

In the microcapsule, the weight of the capsule wall accounts for 10%-30% of the microcapsule, for example, it can be 10%, 12%, 15%, 20%, 25%, 30%, preferably 15%-25%. It has been found that controlling the weight of the capsule wall is easy to control the release rate of oxadiazon.

In the microcapsules of the present invention, the average diameter of the microcapsule particles is 1-25 microns, preferably 2-10 microns, more preferably 3-7 microns. Generally, the particle size of the microcapsules can be controlled by controlling the reaction conditions such as mixing speed, shear force, and mixing time.

In the herbicidal composition of the present invention, the content of the microencapsulated oxadiazon in the herbicidal active is 5%-40%, preferably 10%-30%; more preferably 10%-15%.

In the herbicidal composition of the present invention, the content of microencapsulated oxadiazon in the herbicidal active can also be 5%, 6%, 10%, 12%, 15%, 18%, 20%, 22%. %, 24%, 25%, 28%, 30%, 35%, 40%.

In the herbicidal composition of the present invention, the optional non-microencapsulated second herbicidal active substance can be:

Acetochlor (acet Chlor), activated ester (acibenzolar), benzothiadiazole (acibenzolar-S-methyl), acifluorfen (acifluorfen), aclonifen (aclonifen), alachlor (alachlor), Dipropenol (allid°Chlor), alloxydim, ametryn, amicarbazone, amidosulfuron, aminopyralid, and weed Strong (amitrole), ammonium sulfamate (ammoniμm sulfamate), ancymidol, anilofos, asulam, atrazine, azafenidin, four Azimsulfuron, benfuresate, bensulfuron, bentazone, benzfendizone, benzobicyclon, metazoazone (benzofenap), benzofluor, bicyclopyrone, bispyribac sodium, bromoxynil, butafenacil, butafenacil, butalin, Carfenstrole, carbetamide, carfentrazone, chlorimuron (chlorimuron-ethyl), chlormequat chloride, chlorotoluron, chlorine Chlorsulfuron, cinmethylin, cinosulfuron, clethodim, clomazone, clomeprop, clopyralid ( clopyralid, cyanazine, cyclanilide, cyclosulfamuron, cycloxydim, cyprazole, daimuron/dymron, Dicamba (dicamba), diclofop-methyl, diclofop-P-methyl, diclosulamide (diclos ulam), acetochlor (diethatyl, diethatyl-ethyl), diflufenican (diflufenican), diflufenzopyr (diflufenzopyr-sodium), dimefuron (dimefuron), dimepiperate, Dimethachlor, dimethametryn, diphenamid, dipropetryn, diquat, diuron, methamsulfuron (ethametsulfuron, ethametsulfuron-methyl), ethephon (ethephon), ethidimuron, ethoxysulfuron (ethoxysulfuron), etobenzanid, fenoxaprop, fenoxaprop Fenoxaprop-P, fenoxaprop-ethyl, fentrazamide, flazasulfuron, flazasulfuron, florasulam, flufenoxaprop-ethyl Fluazifop, fluazifop-P (fluazifop-P), fluazifop-butyl, fluazifop-P-butyl, isopyridine Fluazolate (fluazolate), flucarbazone (flucarbazone-sodiμm), flucetosulfuron (flucetosulfuron), flufenacet, flumetralin (flμmetralin), flumetsulam (flμmetsulam), Flumioxazin (flμmioxazin), flumipropyn (flumipropyn), fluometuron, fluorodifen, fluoroglycofen (fluoroglycofen, fluoroglycofen-ethyl), flumipropyn (fluometuron) flupoxam), flupyrsulfuron (flupyrsulfuron), fluridone (fluridone), flurChloridone, fluroxypyr, flurtamone, fluthiamide , Fomesafen, glufosinate (glufosinate-ammonium), glufosinate-P (glufo sinate-P, glufosinate-P-ammonium), glufosinate-P-sodium, glyphosate, glyphosate-isopropylammonium, fluosinate Halosafen, haloxyfop, haloxyfop-P, haloxyfop-ethoxyethyl, haloxyfop-P-ethoxyethyl, fluorine Haloxyfop-methyl (haloxyfop-methyl), haloxyfop-P-methyl, hexazinone, imazamethabenz (imazamethabenz-methyl), imazamox (imazamox, imazamox) -ammonium), imazapic (imazapic), imazapyr (imazapyr-isopropylammonium), imazaquin (imazaquin, imazaquin-ammonium), imazethapyr (imazethapyr, imazethapyr-ammonium), zopyrsulfuron ( imazosulfuron, inabenfide, indanofan, iodosulfuron (iodosulfuron-methyl-sodium), ioxynil, isoproturon, isooxamed (isoxaben), isoxachlortole, clomazone (isoxapyrifop), lactofen (lactofen), lenacil (lenacil), mefenacet (mefenacet), chlorosulfan Amine (mefluidide), mepiquat-chloride (mepiquat-chloride), mesosulfuron (mesosulfuron-methyl), mesotrione (mesotrione), methabenzthiazuron (methabenzthiazuron), metamitron (metamitron) ), metazachlor (metazachlor), methazole (methazole), methiopyrsulfuron (methiopyrsulfuron), methoxyphenone (methoxyphenone), methyldymron (methyldymron), metolachlor (metolachlor) ,fine Metolachlor (S-metolachlor), sulfentrazone (metosulam), metoxuron (metoxuron), metribuzin (metribuzin), metsulfuron (metsulfuron-methyl), molinate , Monosulfuron (monosulfuron), monosulfuron ester (monosulfuron ester), monuron (monuron), napropamide (napropamide), nicosulfuron (nicosulfuron), oxadiazon (oxadiazon), ring Oxasulfuron (oxasulfuron), oxaziclomefone, oxyfluorfen, paclobutrazol, paraquat (paraquat, paraquat dichloride), pentoxazone (pentoxazone), clematis Amine (pethoxamid), picloram, picolinafen, pinoxaden, piperophos, pretilachlor, probenazole ), profluazol, prifluraline, profoxydim, prometryn, propanil, propazine, propham , Propisochlor (propis℃hlor), Propyrisulfuron (propyrisulfuron), propyzamide, Prosulfochlor (prosulf℃arb), Prosulfuron (prosulfuron), Prynachlor ), pyraflufen (pyraflufen-ethyl), pyrazosulfuron (pyrazosulfuron, pyrazosulfuron-ethyl)), pyribambenz-isopropyl, pyribambenz-propyl, saflufenacil Ether (pyribenzoxim), pyributicarb, pyriftalid, pyriminobac-methyl (pyriminobac, pyriminobac-methyl), pyrimisulfan, pyrithiobac (pyrithiobac-sodium), pyroxasulfone, methoxsulam (pyrox sulam), quinchlorac, quinmerac, quizalofop, quizalofop-P, quizalofop-P-ethyl , Rimsulfuron (rimsulfuron), saflufenacil (saflufenacil), secbumeton, sethoxydim, siduron, sulcotrione, sulfentrazone (sulfentrazone), sulfometuron (sulfometuron-methyl), thidiazuron, thifensulfuron (thifensulfuron, thifensulfuron-methyl), thiobencarb, tiCarbazil, ether Triasulfuron (triasulfuron), triaziflam (triaziflam), tribenuron (tribenuron, tribenuron-methyl), trichloroacetic acid (TCA), triclopyr, tridiphane, Trifloxysulfuron (trifloxysulfuron, trifloxysulfuron-sodium), trifluralin, trifluralin, triflusulfuron, triflusulfuron-methyl, trimeturon, trinexapac-ethyl ( trinexapac, trinexapac-ethyl, tritosulfuron (tritosulfuron), and uniconazole.

Therefore, the herbicidal composition containing microencapsulated oxadiazon provided by the present invention can achieve the purpose of the present invention by controlling the combination of the following two or more variables: (1) the molar equivalent ratio of polyamine to polyisocyanate; (2) The weight ratio of the capsule wall to the weight of the microcapsules; (3) The particle size of the microcapsules; (4) The weight ratio of oxadiazon to the solvent.

The release rate of oxadiazon from the encapsulated microcapsules can be controlled by selecting the properties and composition of the microcapsules and selecting the above-mentioned variable parameters. Therefore, it is possible to apply the herbicidal composition of the present invention before planting crops or before crop emergence, which can simultaneously give commercially acceptable weed control and commercially acceptable crop damage.

The release rate distribution of the microencapsulated herbicidal composition of oxadiazon provided by the present invention provides commercially acceptable crop safety and weed control.

The present invention also provides a method for preparing the herbicidal composition containing microcapsules of the present invention, which comprises the following steps:

i) Provide a mixed oil phase containing oxadiazone in a molten state, the first vesicle-forming wall component, and one or more solvents;

ii) Provide an aqueous phase containing water and optionally one or more surfactants;

iii) Combine the above-mentioned mixed oil phase with the water phase to form a dispersion of the oil phase in a continuous water phase;

iv) adding a second vesicle-forming component to the above dispersion, so that the first vesicle-forming component and the second vesicle-forming component undergo interfacial polymerization, thereby wrapping the droplets of the oil phase; and The temperature of the interfacial polymerization reaction is 25℃-60℃;

v) mixing the oxadiazon-containing microcapsules obtained above and an optional second herbicidal active component in the presence of at least one agriculturally acceptable additive to prepare the herbicidal composition containing oxadiazon microcapsules;

or

i) Provide a mixed oil phase containing oxadiazon, the first vesicle wall component, and one or more solvents;

ii) Provide an aqueous phase with water and optionally one or more surfactants;

iii) Combine the above-mentioned mixed oil phase with the water phase to form a dispersion of the oil phase in a continuous water phase;

iv) adding a second vesicle-forming component to the above dispersion, so that the first vesicle-forming component and the second vesicle-forming component undergo interfacial polymerization, thereby wrapping the droplets of the oil phase; and The temperature of the interfacial polymerization reaction is 25℃-60℃;

v) Mixing the oxadiazone-containing microcapsules obtained above and an optional second herbicidal active component in the presence of at least one agriculturally acceptable additive to prepare the microcapsule-containing herbicidal composition.

Preferably, the melting temperature is between 25°C and 60°C, for example, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C; The state where the oxadiazon and the second herbicidal active are completely melted shall prevail.

Preferably, the temperature of the interfacial polymerization reaction is between 25°C and 60°C, for example, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C.

Suitable methods for interfacial polymerization methods for preparing microcapsules containing pesticide compounds have been disclosed in the prior art, for example, US3577515A1, US4280833A1, US5049182A1, WO95/13698A1, WO03/099005A1, EP619073A1 or EO1109450A1, refer to all of these patents.

In the preparation method of the herbicidal composition, the obtained oxadiazon and optional second herbicidal active component are mixed in the presence of at least one agriculturally acceptable additive to form the herbicidal combination containing microcapsules Things.

The agriculturally acceptable additives include liquid diluents or carriers, solid diluents or carriers, emulsifiers, dispersants, thickeners, and stabilizers.

The liquid diluent or carrier is usually: aromatic compounds such as xylene, toluene or alkyl naphthalene, aliphatic alkanes such as cyclohexane or paraffins such as petroleum distillates, mineral and vegetable oils, alcohols such as butanol or ethylene glycol and their Ethers and esters, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone, N-methylpyrrolidone, strong polar solvents such as dimethyl formamide and dimethyl sulfoxide, or water.

The solid diluent or carrier is: for example, ammonium salts and crushed natural minerals such as kaolin, clay, talc, quartz, attapulgite, montmorillonite or silicate, and crushed synthetic minerals such as highly dispersed two Silicon oxide, silicon oxide and silicate.

Suitable emulsifiers are: for example, nonionic and anionic emulsifiers, such as polyoxyethylene fatty acid, polyoxyethylene fatty alcohol ether, such as alkyl aryl polyglycol ether, alkyl sulfonate, alkyl sulfate, aromatic Sulfonate, or protein hydrolysate. Suitable dispersants are: for example, lignosulfite waste liquor and methyl cellulose.

Tackifiers such as carboxymethyl cellulose, and natural and synthetic polymers in powder, granule or latex form, such as gum arabic, polyvinyl alcohol and polyvinyl acetate or natural phospholipids, such as cephalin and lecithin, can be used, and Synthetic phospholipids. Other additives are mineral oil and vegetable oil.

The present invention also provides a method for controlling weeds in a crop field, the method comprising applying the herbicidal composition of the present invention to the field in a herbicidal effective amount, and (i) before planting the crop or (ii) The herbicidal composition is applied to the field before the crop emerges.

The weeds mainly include gramineous weeds, such as brome, Aegilops, wild oats, and sylvestris; broadleaf weeds, such as Sorrel, Artemisia sowing, Shepherd's Purse, Zeqi, Granny, and Oats Family father and so on.

The herbicidal composition provided by the present invention provides more lasting control of weeds.

The present invention also provides a method for reducing crop damage. The herbicidal composition of the present invention is applied to the field (i) before planting the crop or (ii) before the crop emerges.

For common single agents of oxadiazon on the market, such as EC products, when encountering heavy rain or over-irrigation, the active ingredients infiltrate due to rain washing, which will cause certain phytotoxicity to the germinated seed crops. However, applying the herbicidal composition provided by the present invention to the field before planting the crop or before the emergence of the crop can significantly reduce the damage of oxadiazon to the crop and provide lasting control of weeds.

The crop is selected from soybean, cotton, peanut, rice, wheat, rape, alfalfa, sugar cane, sorghum and sunflower.

Compared with the prior art, the present invention has at least the following beneficial effects:

The herbicidal composition containing microcapsules provided by the present invention, applied before crops are planted or before crop emergence, can simultaneously give commercially acceptable weed control and commercially acceptable crop damage.

Detailed ways

To facilitate the understanding of the present invention, examples of the present invention are listed below. Those skilled in the art should understand that the described embodiments are only to help understand the present invention and should not be regarded as specific limitations to the present invention.

Example 1: 25% oxadiazon microcapsule suspension

Table 1

ingredient	Dosage
Oxachlor	25.00%
Isooctyl Palmitate	20.00%
Toluene diisocyanate	5.00%
Ethylenediamine	1.00%
1,6-Hexanediamine	2.00%
Polyvinyl alcohol	1.00%
Lignosulfonate	2.00%
Naphthalenesulfonate formaldehyde condensation polymer	3.00%
Silicone oil defoamer	0.50%
Sodium hydroxide	1.00%
Xanthan gum	0.15%
Isothiazolinone	0.20%
Propylene Glycol	5.00%
water	Make up to 100%

Heat the mixture of oxadiazon, toluene diisocyanate, and isooctyl palmitate according to the above ratio to melt into a liquid oil phase for later use; mix polyvinyl alcohol, silicone oil defoamer, lignin sulfonate, naphthalene sulfonate formaldehyde The polycondensate is dissolved in water to form an aqueous phase; the oil phase is added to the water under shear conditions to form an emulsion, and the emulsion is maintained at about 60°C. Slowly add a proportion of ethylenediamine and 1,6-ethylenediamine to polymerize. React until the reaction is complete. Cool the reaction liquid to room temperature, add a proportion of sodium hydroxide to adjust the pH value of the solution, and a proportion of propylene glycol, xanthan gum, and isothiazolinone to stir evenly to obtain oxadiazon 25% microcapsule suspension; control micro The average particle size of the capsule is about 6 μm.

Example 2: 12.5% oxadiazon microcapsule suspension

Table 2

ingredient	Dosage
Oxachlor	12.5%
Methyl Hydrogenated Rosinate	20.00%
Toluene diisocyanate	5%
1,6-Hexanediamine	4%
Polyvinyl alcohol	1.00%
Lignosulfonate	2.00%
Naphthalenesulfonate formaldehyde condensation polymer	3.00%
Silicone oil defoamer	0.50%
Sodium hydroxide	1.00%
Xanthan gum	0.15%
Isothiazolinone	0.20%
Propylene Glycol	5.00%
water	Make up to 100%

Heat the mixture of oxadiazon, toluene diisocyanate, and methyl hydrogenated rosinate according to the above ratio to melt into a liquid oil phase for later use; mix polyvinyl alcohol, silicone oil defoamer, lignin sulfonate, naphthalene sulfonate formaldehyde The polycondensate is dissolved in water to form an aqueous phase; the oil phase is added to the water under shear conditions to form an emulsion, keeping the emulsion at about 60°C, slowly adding a proportion of 1,6-ethylenediamine to the polymerization reaction until the reaction complete. Cool the reaction solution to room temperature, add a proportion of sodium hydroxide to adjust the pH of the solution, and a proportion of propylene glycol, xanthan gum, and isothiazolinone to stir evenly to obtain a 12.5% microcapsule suspension of oxadiazon; control micro The average particle size of the capsule is about 6 μm.

Example 3: 6% oxadiazon microcapsule suspension.

table 3

ingredient	Dosage
Oxachlor	6.00%
Methyl oleate	10.00%
Polymethylene polyphenyl polyisocyanate	4.20%
Diethylenetriamine	1.80%
Polyvinyl alcohol	1.00%
Lignosulfonate	3.00%
Naphthalenesulfonate formaldehyde condensation polymer	3.00%
Silicone oil defoamer	1.00%
Sodium hydroxide	1.00%
Xanthan gum	0.10%
Isothiazolinone	0.10%
Propylene Glycol	5.00%
water	48.3%

Heat the mixture of oxadiazon, polymethylene polyphenyl polyisocyanate, and methyl oleate according to the above ratio to melt into a liquid oil phase for use; combine polyvinyl alcohol, silicone oil defoamer, lignosulfonate, The naphthalene sulfonate formaldehyde polycondensate is dissolved in water to form an aqueous phase; the oil phase is added to the aqueous phase under shear conditions to form an emulsion, keeping the emulsion at about 50°C, slowly adding diethylenetriamine dropwise to polymerize until the reaction complete. Cool the reaction solution to room temperature, add formula amount of sodium hydroxide to adjust the pH value of the solution, and formula amount of propylene glycol, xanthan gum, isothiazolinone and stir evenly to obtain 6% oxadiazon microcapsule suspension, and control the microcapsule The average particle size is about 6 μm.

Example 4: 38% oxadiazon microcapsule suspension

Table 4

ingredient	Dosage
Oxachlor	38.00%
Aromatic solvent	30.00%
Polymethylene polyphenyl polyisocyanate	6.00%
Diethylenetriamine	2.60%
Polyvinyl alcohol	1.00%
Lignosulfonate	3.00%
Naphthalenesulfonate formaldehyde condensation polymer	3.00%
Silicone oil defoamer	1.00%
Sodium hydroxide	1.00%
Xanthan gum	0.10%
Isothiazolinone	0.10%
Propylene Glycol	5.00%
water	Make up to 100%

According to the above ratio, dissolve oxadiazon and polymethylene polyphenyl polyisocyanate in an aromatic solvent at 50°C to form an oil phase; combine polyvinyl alcohol, silicone oil defoamer, lignin sulfonate, and naphthalene sulfonate The formaldehyde polycondensate is dissolved in water to form an aqueous phase; the oil phase is added to the aqueous phase to form an emulsion under shearing conditions, and the emulsion is maintained at about 50°C, and diethylenetriamine is slowly added dropwise for polymerization until the reaction is complete. Cool the reaction solution to room temperature, add a formula amount of sodium hydroxide to adjust the pH value of the solution, and a formula amount of propylene glycol, xanthan gum, and isothiazolinone to stir evenly to obtain a 38% oxadiazon microcapsule suspension microcapsule suspension; The average particle size of the control microcapsules is about 6 μm.

Biological test case

The herbicide effect data shown in this article is recorded as the percentage of phytotoxicity of crop damage and weed suppression after standard procedures in the field. These observations are made and recorded by specially trained technicians, and the feedback is compared with untreated plants. Visual evaluation of plant mortality and growth decline. In all cases, a single technician made all assessments of the% inhibition in any one experiment or within the experiment.

The composition of the present invention can be applied to soil or plants by spraying using any conventional method of spraying liquid such as spray nozzles, atomizers, and the like. When applied to soil or plants, the composition is preferably sufficiently diluted to be easily sprayed using standard agricultural spray equipment. The preferred application rate of the present invention varies depending on a number of factors, including the type and concentration of active ingredients and the plant species involved. The selection of a suitable application rate is within the abilities of those skilled in the art.

The preparation products obtained by mixing a large number of microcapsules and non-encapsulated components of the present invention are introduced in the following examples. Many formulations have provided sufficient herbicide effects in greenhouse tests to ensure field testing of a large number of weed species under various application conditions.

The herbicidal activity of the compound is visually inspected by the degree of plant damage symptoms (inhibition, deformity, yellowing, albino), 0 means no herbicidal effect or safety to the crop, and 100% means complete killing of weeds or crops. See Table 5 for the evaluation criteria of herbicidal activity and crop safety visual inspection method, and Table 6 for the selected biological activity determination experimental targets.

table 5

Table 6

Chinese name	English name
Brome	Japanese Bromegrass
Pig sorrow	Tender Catchweed Bedstraw Herb
Gooseweed	Goosegrass
purslane	Portulacae Herba

The herbicidal effect and safety of the preparation product of the present invention were evaluated by using 12.5% oxadiazon EC (control sample 1) from a commercially available company. Experiments show that compared to the control samples, the encapsulated microcapsule formulations containing oxadiazon showed improved crop safety when tested on wheat, soybeans and cotton; at the same time, the medium and long-term effects on weeds were comparable or even superior. In the control sample.

Test Example 1 The safety of the microcapsule preparation containing oxadiazon as the core of the microcapsules in the application of pre-emergence crops of wheat, soybeans and cotton will be prepared in Examples 1-4 immediately after planting winter wheat, soybeans or cotton The microencapsulated herbicide containing oxadiazon as the core is applied to the soil. The phytotoxicity was determined at 18 days. The results are shown in the table below.

Wheat safety evaluation

Winter wheat was sown in a pot containing a 50:50 silt loam: artificial soil (redi-earth soil) mixture. Immediately after planting, the microencapsulated herbicides of Examples 1-4 were treated with the application rates of 450g A.I/ha, 500g A.I/ha, 750g A.I/ha, and the pre-emergence application of control sample 1. The plant 18DAT was evaluated for leaf damage, and the results are recorded in Table 7 below.

Table 7

The above results indicate that the microencapsulated herbicide with oxadiazon as the core material significantly reduces the damage of oxadiazon to wheat.

Soybean safety evaluation

Glyphosate tolerant (ROUNDUP READY) soybeans were planted in pots containing a 50:50 silt loam: artificial soil (redi-earth soil) mixture. Immediately after planting, the microencapsulated herbicides of Examples 1-4 were treated with the application rates of 450g A.I/ha, 500g A.I/ha, 750g A.I/ha, and control sample 1 was applied before emergence. The plant 18DAT was evaluated for leaf damage, and the results are recorded in Table 8 below.

Table 8

The above results indicate that the microencapsulated herbicide with oxadiazon as the core material significantly reduces the damage of oxadiazon to soybeans.

Cotton safety evaluation:

Cotton was planted in a pot containing a 50:50 silt loam: artificial soil (redi-earth soil) mixture. Immediately after planting, the microencapsulated herbicides of Examples 1-4 were treated with the application rates of 450g A.I/ha, 500g A.I/ha, 750g A.I/ha, and the pre-emergence application of control sample 1. The plant 18DAT was evaluated for leaf damage and the results are recorded in Table 9 below.

Table 9

The above results indicate that the microencapsulated herbicide with oxadiazon as the core material significantly reduces the damage of oxadiazon to cotton.

Test Example 2: Experimental study on weed control efficiency of microcapsule preparation containing oxadiazon as the core of microcapsules in pre-emergence crop applications

The pre-emergence experiment was carried out in the greenhouse pot method. The experimental soil was prepared sandy loam soil, and the pot diameter for the herbicidal activity experiment was 9.5 cm. The soil surface was sprayed one day after sowing, and the treated medicinal solution was the preparations of Examples 1-4 and Control 1, diluted with water to the required dosage.

After the treated pots were allowed to stand for 1 day, they were put into the greenhouse and watered regularly. After 4-21 days, the herbicidal activity of each compound was observed and recorded visually. The results of the herbicidal activity measurement for 7 days after application are shown in Table 24. Application The results of the 45-day herbicidal activity determination are shown in Table 25.

Table 10 Control effect 7 days after drug

Table 11 Control effect 45 days after drug

The above results indicate that the microencapsulated oxadiazone preparation product exhibits a longer-lasting control effect than the control sample in herbicidal activity 45 days after application, and is safe for crops.

Claims (19)

1. A herbicidal composition containing microcapsules, characterized in that the herbicidal composition comprises microencapsulated oxadiazone and optionally a non-encapsulated second herbicidal active substance.
2. The herbicidal composition according to claim 1, wherein the second herbicidal active substance is selected from pendimethalin, mesotrione, oxadiazon, flumioxazin, siquan, fenthiazole Axachlor, dichlorfentrazone, oxadiazon, clomazone, oxyfluorfen, carfentrazone-ethyl, clethodim, cyhalofop-butyl, dichlorfenazone, wild carbamide, grass Meclofen, Pafentrazone, Penoxazone, Tetrafentrazone, Fluprofen, Flufen-ethyl, Cyclozinone, Buclofenone, Thioxachlor, Sethoxypyr, Pyran Fluroxyfen, cyclofenazone, aclofen, chlorflufen, oxyfluorfen, lactofop-p-ethyl, fluroxypyr, clodinafop-ethyl, fenoxaprop-p-ethyl, sulfafenphos, pyraclostrobin Fluroxypyr, quizalofop-p-ethyl, flufenacet, flufenacet, acetochlor, alachlor, butachlor, metazachlor, metolachlor, high-efficiency metolachlor, C Any one or a combination of at least two of grass amine, propisochlor, metolachlor, trifluralin, chloridan, or indoxazone.
3. The herbicidal composition according to claim 1, wherein the mass ratio of the second herbicidal active substance to oxadiazon is 1:10-10:1, preferably 1:5-5:1.
4. The herbicidal composition according to claim 1, wherein the microcapsules further contain one or more solvents; and the weight ratio of the herbicidal active substance to the solvent in the microcapsules is 1:10-10: 1; preferably 1:5-5:1; more preferably 1:2.5-2.5:1.
5. The herbicidal composition according to claim 4, wherein the one or more solvents contained in the microcapsules are selected from aromatic hydrocarbon solvents, isooctyl palmitate, methyl oleate, hydrogenated rosin, polymerized rosin, Any one or a combination of at least two of rosin ester or polyhydric alcohol ester.
6. The herbicidal composition according to claim 1, wherein the microcapsule has a porous polymer wall material, and the polymer wall material is selected from the group consisting of polyurea, polyurethane, polyamide, and polycarbonate. Combinations of ester, polysulfonamide, urea formaldehyde, melamine resin, melamine urea resin, gelatin, gum arabic cross-linked and uncross-linked.
7. The herbicidal composition according to claim 6, wherein the weight of the microcapsule wall accounts for 10%-30% of the microcapsule, preferably 15%-25%.
8. The herbicidal composition according to claim 6, wherein the polymer capsule wall material is a polyurea capsule wall obtained by the reaction of polyisocyanate and polyamine.
9. The herbicidal composition according to claim 8, wherein the ratio of the molar equivalent of amine contained in the polyamine to the molar equivalent of isocyanate contained in the polyisocyanate is at least 1.1:1.
10. The herbicidal composition according to claim 9, wherein the ratio of the molar equivalent of amine contained in the polyamine to the molar equivalent of isocyanate contained in the polyisocyanate is 1.15:1 to 1.3:1.
11. The herbicidal composition according to claim 8, wherein the polyisocyanate is selected from the group consisting of polymethylene polyphenyl isocyanate, diphenylmethane isocyanate, polymethylene diphenyl isocyanate or toluene diisocyanate Any one or a combination of at least two.
12. The herbicidal composition according to claim 8, wherein the polyamine is selected from the group consisting of ethylenediamine, diethyltriamine, triethylenetetramine, 1,6-hexanediamine, triethylamine, and Any one or a combination of at least two of ethylenepentamine.
13. The herbicidal composition according to claim 1, wherein the average diameter of the microcapsule particles is 1-25 microns, preferably 2-10 microns, more preferably 3-7 microns.
14. The herbicidal composition according to claim 1, wherein the content of the oxadiazon is 5%-40%, preferably 10%-30%, more preferably 10%-15% of the herbicidal composition.
15. A method for preparing the herbicidal composition containing microcapsules according to any one of claims 1-14, characterized in that it comprises the following steps:

    i) Providing a mixed oil phase containing oxadiazon in a molten state, the first vesicle-forming wall component, and one or more solvents; and the melting temperature is 25°C-60°C;

    ii) Provide an aqueous phase containing water and optionally one or more surfactants;

    iii) Combine the above-mentioned mixed oil phase with the water phase to form a dispersion of the oil phase in a continuous water phase;

    iv) adding a second vesicle-forming component to the above dispersion, so that the first vesicle-forming component and the second vesicle-forming component undergo interfacial polymerization, thereby wrapping the droplets of the oil phase; and The temperature of the interfacial polymerization reaction is 25℃-60℃;

    v) mixing the obtained microcapsules containing oxadiazon and the second herbicidal active substance in the presence of at least one agriculturally acceptable additive to prepare the herbicidal composition containing microcapsules;

    or

    i) Provide a mixed oil phase containing oxadiazon, the first vesicle wall component, and one or more solvents;

    ii) Provide an aqueous phase with water and optionally one or more surfactants;

    iii) Combine the above-mentioned mixed oil phase with the water phase to form a dispersion of the oil phase in a continuous water phase;

    iv) adding a second vesicle-forming component to the above dispersion, so that the first vesicle-forming component and the second vesicle-forming component undergo interfacial polymerization, thereby wrapping the droplets of the oil phase; and The temperature of the interfacial polymerization reaction is 25℃-60℃;

    v) Mixing the oxadiazone-containing microcapsules obtained above and an optional second herbicidal active component in the presence of at least one agriculturally acceptable additive to prepare the microcapsule-containing herbicidal composition.
16. The method according to claim 15, wherein the first vesicle-forming component is a polyisocyanate; the second vesicle-forming component is a polyamine.
17. A method for controlling weeds in a crop field, characterized in that the method comprises applying the herbicidal composition containing microcapsules of claim 1 to the field in a herbicidal effective amount, and (i) in planting The herbicidal composition is applied to the field before the crop or (ii) before the emergence of the crop.
18. The method according to claim 17, wherein the crop is selected from soybean, cotton, peanut, rice, wheat, rape, alfalfa, sugar cane, sorghum and sunflower.
19. A method for reducing crop damage, characterized in that the herbicidal composition containing microcapsules according to claim 1 is applied to the field (i) before planting the crop or (ii) before the crop emerges.