Weeding Concentrate Aqueous Solution

Abstract

A herbicidal concentrate composition containing a herbicide combination is provided. Specifically, the present invention relates to a herbicidal aqueous concentrate composition containing a microencapsulated acetanilide herbicide and a protoporphyrinogen oxidase inhibitor (PPO inhibitor).

Description

[0001] This application is a divisional application of the patent application for "aqueous herbicide concentrate" with the application number 201580005688.5, filed on January 27, 2015. Technical Field

[0002] The present invention generally relates to herbicidal concentrate compositions containing herbicide combinations. Specifically, the present invention relates to herbicidal aqueous concentrate compositions containing microencapsulated acetanilide herbicides and protoporphyrinogen oxidase inhibitors (PPO inhibitors). Background Art

[0003] The emergence of certain herbicide-resistant weeds has generated interest in developing strategies to augment the action of post-emergence herbicides such as glyphosate. Acetanilide herbicides are known as effective residual herbicides for reducing early weed competition. Specifically, acetanilide herbicides such as acetochlor provide excellent residual control of many grasses and broadleaf weeds including pigweed, waterhemp, lambsquarter, nightshade, foxtail, etc. Acetanilides are generally classified as seedling growth inhibitors. In plants, from germination to emergence, seedling growth inhibitors are mainly absorbed and translocated through newly emerged underground shoots and / or seedling roots. Acetanilide herbicides generally do not provide significant post-emergence activity, but provide control of newly emerged monocotyledonous and small-seeded dicotyledonous weed species as residual herbicides. This complements the activity of post-emergence herbicides that lack significant residual activity.

[0004] Crop damage caused by the application of acetanilide herbicides has made it necessary to develop strategies to reduce this effect. One strategy involves applying acetanilide herbicide formulations after crop emergence (i.e., post-emergence to the crop), but before the emergence of late-germinating weeds (i.e., pre-emergence to the weeds). However, application during this time window can cause foliar damage to the crop. Another strategy for reducing crop damage involves microencapsulating acetanilide herbicides. Methods for producing microencapsulated acetanilide herbicides are described in various patents and publications including U.S. Patent No. 5,925,595, U.S. Publication No. 2004 / 0137031, and U.S. Publication No. 2010 / 0248963.

[0005] Another class of herbicides having effective residual control and activity against persistent herbicide - resistant weeds such as Amaranthus palmeri includes protoporphyrinogen oxidase (PPO) inhibitors. PPO inhibitors include herbicides such as acifluorfen, azafenidin, bifenox, butafenacil, carfentrazone - ethyl, flufenpyr - ethyl, flumiclorac, flumiclorac - pentyl, flumioxazin, fluoroglycofen, fluthiacet - methyl, fomesafen, lactofen, oxadiargyl, oxadiazon, oxyfluorfen, pyraflufen - ethyl, saflufenacil, and sulfentrazone, their salts and esters, and mixtures thereof.

[0006] Herbicide compositions containing combinations of herbicides having multiple modes of action and capable of complementing the action of a pre - herbicide such as glyphosate are particularly suitable for controlling the growth of noxious plants, including plants having selected herbicide resistance.

[0007] In the art, tank - mix compositions of encapsulated acetanilide herbicides and PPO inhibitors are known. However, the mixtures are typically prepared by the end - user at the time of use. There is still a need for highly concentrated herbicidal compositions containing encapsulated acetanilide herbicides and PPO inhibitors that are convenient for agricultural workers to formulate into spray solutions and avoid the risk of tank - mix errors.

[0008] Furthermore, the stability of encapsulated acetanilide herbicidal concentrates is sensitive to the inclusion of additional additives, including co - herbicides. Accordingly, there is still a need for highly concentrated herbicidal compositions containing encapsulated acetanilide herbicides and PPO inhibitors that can be produced economically, have sufficient stability, and can be diluted to provide an effective spray formulation solution for application to noxious plants. SUMMARY OF THE INVENTION

[0009] In one aspect, the present invention relates to a concentrated aqueous herbicidal composition comprising:

[0010] microcapsules containing an acetanilide herbicide, wherein the concentration of the acetanilide herbicide in the composition is at least about 25% by weight based on the active ingredient;

[0011] A water-soluble protoporphyrinogen oxidase inhibitor (PPO inhibitor); and

[0012] A pseudoplastic thickener of at least about 750 ppm based on the total weight of the composition.

[0013] On the other hand, the present invention relates to a concentrated aqueous herbicidal composition comprising:

[0014] Microcapsules containing an acetanilide herbicide, wherein the concentration of the acetanilide herbicide in the composition is at least about 25% by weight based on the active ingredient;

[0015] A water-soluble protoporphyrinogen oxidase inhibitor (PPO inhibitor);

[0016] A structure breaker with a concentration not exceeding about 3.5% by weight; and

[0017] A density regulator, wherein the total concentration of the structure breaker and the density regulator is about 7% to about 10% by weight, about 7.5% to about 9% by weight, or about 8% to about 9% by weight.

[0018] In yet another aspect, the present invention relates to a concentrated aqueous herbicidal composition comprising:

[0019] Microcapsules containing an acetanilide herbicide, wherein the concentration of the acetanilide herbicide in the composition is at least about 25% by weight based on the active ingredient;

[0020] A water-soluble protoporphyrinogen oxidase inhibitor (PPO inhibitor);

[0021] A pseudoplastic thickener of at least about 750 ppm based on the total weight of the composition;

[0022] A structure breaker with a concentration not exceeding about 3.5% by weight; and

[0023] A density regulator, wherein the total concentration of the structure breaker and the density regulator is about 7% to about 10% by weight, about 7.5% to about 9% by weight, or about 8% to about 9% by weight.

[0024] In yet another aspect, the present invention relates to a concentrated aqueous herbicidal composition comprising:

[0025] Microcapsules comprising a core material containing an acetanilide herbicide and a shell wall material encapsulating the core material;

[0026] An aqueous phase, comprising the acetanilide herbicide (uncapsulated acetanilide) and a water-soluble protoporphyrinogen oxidase inhibitor (PPO inhibitor), wherein the total acetanilide herbicide concentration in the composition is at least about 25% by weight based on the active ingredient; the weight ratio of the total acetanilide herbicide to the PPO inhibitor is from about 1:10 to 10:1; and the concentration of the acetanilide herbicide in the aqueous phase is from about 0.5% to about 10% of the total weight of the acetanilide herbicide.

[0027] Other objects and features will be in part apparent and in part pointed out hereinafter. Detailed Description

[0028] Generally, the present invention relates to a concentrated aqueous herbicidal composition comprising a combination of at least one encapsulated acetanilide herbicide and at least one PPO inhibitor herbicide.

[0029] One aspect of the present invention is to provide a highly concentrated herbicidal composition containing at least one encapsulated acetanilide herbicide and at least one PPO inhibitor, which can be diluted to provide an effective spray formulation solution. The highly concentrated composition reduces the volume of liquid and associated packaging that would otherwise be required for a more dilute composition. The smaller the volume, the less space required for storing and transporting the concentrated composition before sale or use. Further, the highly concentrated herbicidal composition containing an acetanilide herbicide and a PPO inhibitor facilitates formulation by agricultural workers into a spray solution and avoids the risk of tank mixing errors.

[0030] Another aspect of the present invention is to provide a highly concentrated herbicidal composition containing an encapsulated acetanilide herbicide and a PPO inhibitor, which is stable and does not significantly separate into phases, form precipitates or gels upon standing or storage. The stable and compatible highly concentrated herbicidal composition advantageously provides a uniform spray formulation solution after dilution without excessive agitation.

[0031] According to the present invention, the concentrated composition comprises a PPO inhibitor. PPO inhibitors include herbicides such as acifluorfen, azafenidin, bifenox, butafenacil, carfentrazone-ethyl, flufenpyr-ethyl, flumiclorac-pentyl, flumioxazin, fluthiacet-methyl, fomesafen, lactofen, propyzamide, oxadiazon, oxyfluorfen, pyraflufen-ethyl, sulfentrazone and metosulam, their salts and esters and mixtures thereof. Some PPO inhibitor herbicides may be in their free form, used as salts or derivatives, such as esters. In various embodiments, the concentrated composition comprises a water-soluble PPO inhibitor. In some embodiments, the water-soluble PPO inhibitor is a water-soluble salt selected from the group consisting of fomesafen and acifluorfen. In certain embodiments, the water-soluble PPO inhibitor is a water-soluble salt selected from the group consisting of sodium fomesafen and sodium acifluorfen. In additional embodiments, the water-soluble PPO inhibitor comprises sodium fomesafen.

[0032] Generally, the concentrated aqueous herbicide composition of the present invention contains, by active ingredient, at least about 2 wt%, at least about 4 wt%, at least about 5 wt%, at least about 6 wt% or at least about 8 wt% of a PPO inhibitor. In these and other embodiments, the concentrated aqueous herbicide composition contains, by active ingredient, from about 2 wt% to about 20 wt%, from about 4 wt% to about 20 wt%, from about 5 wt% to about 20 wt%, from about 5 wt% to about 15 wt%, from about 5 wt% to about 10 wt%, from about 6 wt% to about 15 wt% or from about 6 wt% to about 10 wt% of a PPO inhibitor.

[0033] The concentrated composition further comprises an encapsulated acetanilide herbicide (e.g., microcapsules of an acetanilide herbicide). Acetanilide herbicides include herbicides such as acetochlor, alachlor, butachlor, butenachlor, delachlor, diethatyl, dimethachlor, mefenacet, metazochlor, metolachlor, S-metolachlor, pretilachlor, propachlor, propisochlor, prynachlor, terbuchlor, thenylchlor, and xylachlor, mixtures thereof, and their stereoisomers. Some acetanilide herbicides may be in their free form, used as salts or derivatives, such as esters. In various embodiments, the acetanilide herbicide is selected from the group consisting of acetochlor, alachlor, butachlor, metolachlor, and S-metolachlor. In certain embodiments, the acetanilide herbicide is selected from the group consisting of acetochlor, metolachlor, and S-metolachlor. In various embodiments, the acetanilide herbicide comprises acetochlor.

[0034] The concentrated aqueous herbicide composition of the present invention contains, by active ingredient, at least about 15 wt%, at least about 20 wt%, at least about 25 wt%, at least about 30 wt% or at least about 35 wt% of an acetanilide herbicide. In these and other embodiments, the concentrated aqueous herbicide composition contains, by active ingredient, from about 15 wt% to about 40 wt%, from about 20 wt% to about 40 wt%, from about 20 wt% to about 35 wt%, from about 20 wt% to about 30 wt%, from about 25 wt% to about 40 wt%, from about 25 wt% to about 35 wt%, from about 30 wt% to about 40 wt% or from about 30 wt% to about 35 wt% of an acetanilide herbicide.

[0035] The weight ratio of the total acetanilide herbicide to the PPO inhibitor, on an acid equivalent (a.e.) basis, is from about 1:10 to about 10:1, from about 1:8 to about 8:1, from about 1:6 to about 6:1. In each embodiment, the weight of the acetanilide herbicide is greater than the weight of the PPO inhibitor. Thus, the weight ratio of the total acetanilide herbicide to the PPO inhibitor, on an acid equivalent basis, is from about 2:1 to about 10:1, from about 2:1 to about 8:1, from about 3:1 to about 10:1, from about 3:1 to about 8:1, from about 4:1 to about 10:1, from about 4:1 to about 8:1, from about 5:1 to about 10:1, or from about 5:1 to about 8:1.

[0036] Generally, at least a portion of the acetanilide herbicide component of the concentrated composition of the present invention is encapsulated (e.g., in microcapsules). Encapsulated acetanilide herbicides for use in the present invention can be prepared by contacting a continuous aqueous phase containing a polyamine component comprising a source of polyamine with a discontinuous oil phase containing the acetanilide herbicide and a polyisocyanate component comprising a source of polyisocyanate. A polyurea shell wall is formed in a polymerization reaction between the source of polyamine and the source of isocyanate at the oil / water interface, thereby forming capsules or microcapsules containing the acetanilide herbicide. Thus, microcapsules containing the acetanilide herbicide can comprise a polyurea shell wall.

[0037] One or more polyisocyanates can be used to form the polyurea polymer shell wall of the microcapsules, i.e., each molecule has two or more isocyanate groups. In some embodiments, an admixture of at least two polyisocyanates is used to form the polyurea shell wall. For example, at least one diisocyanate and at least one triisocyanate are used in an interfacial polymerization reaction to form the polyurea shell wall. A variety of polyisocyanates can be employed. For example, the polyisocyanate component can comprise aliphatic polyisocyanates such as hexamethylene diisocyanate-based polyisocyanates (e.g., DESMODUR N3200 and DESMODUR N 3215).

[0038] The source of polyamine can be a single polyamine species or a mixture of two or more different polyamine species. In some embodiments of the present invention, the source of polyamine consists essentially of a primary polyamine. As used herein, a primary polyamine is a polyamine consisting essentially of a single polyamine species. The source of polyisocyanate can also be a single polyisocyanate species or a mixture of two or more different polyisocyanate species. See, for example, U.S. Patent No. 5,925,595, U.S. Publication No. 2004 / 0137031, and U.S. Publication No. 2010 / 0248963, which are incorporated herein by reference.

[0039] Generally, the aqueous dispersion of acetanilide capsules or microcapsules can be produced by interfacial polymerization reaction continuously or batchwise in a manner known in the art. However, preferably, polyamine is polymerized with one or more polyisocyanates at the interface of the oil-in-water emulsion. The discontinuous oil phase (also referred to herein as the "inner phase") preferably contains one or more polyisocyanates and the continuous aqueous phase (also referred to herein as the "outer phase") contains the main amine. The oil phase also contains the core material, which contains an acetanilide herbicide as the active ingredient.

[0040] Preferably, the oil-in-water emulsion is formed by adding the oil phase to the continuous aqueous phase to which an emulsifier or dispersant (e.g., previously dissolved therein) has been added. The emulsifier is selected to obtain the desired oil droplet size in the emulsion. In addition to the emulsifier employed, the size of the oil droplets in the emulsion is affected by many factors and determines the size of the microcapsules formed by this process. The emulsifier is preferably a protective colloid. A polymeric dispersant is preferably used as the protective colloid. The polymeric dispersant provides steric stabilization for the emulsion by adsorbing onto the surface of the oil droplets and forming a high-viscosity layer that prevents the oil droplets from coalescing. The polymeric dispersant can be a surfactant and is preferably a non-polymeric surfactant because the polymeric compound forms a more rigid interfacial film around the oil droplets. If the protective colloid is ionic, the layer formed around each oil droplet will also be used for electrostatically preventing the oil droplets from coalescing. SOKALAN (available from BASF), a maleic acid-olefin copolymer, is a preferred protective colloid, as are INVALON (available from Huntsman) and AGNIQUE NSC 11NP (available from BASF), which are naphthalene sulfonate condensates.

[0041] Other protective colloids for use in the present invention are gelatin, casein, polyvinyl alcohol, alkylated polyvinyl pyrrolidone polymers, maleic anhydride-methyl vinyl ether copolymers, styrene-maleic anhydride copolymers, maleic acid-butadiene and diisobutylene copolymers, sodium and calcium lignosulfonates, sulfonated naphthalene-formaldehyde condensates, modified starches and modified cellulose plastics such as hydroxyethyl or hydroxypropyl cellulose and carboxymethyl cellulose.

[0042] Advantageously, the polyamine component and the polyisocyanate component are selected such that the polyamine has an amine functionality of at least 2, i.e., 3, 4, 5 or higher, and at least one polyisocyanate has an isocyanate functionality of at least 2, i.e., 2.5, 3, 4, 5 or higher, because the high amine and isocyanate functionalities increase the percentage of crosslinking that occurs between the individual polyurea polymers that make up the shell wall. In some embodiments, the polyamine has an amine functionality greater than 2 and the polyisocyanate is a polyisocyanate mixture, wherein each polyisocyanate has an isocyanate functionality greater than 2. In other embodiments, the polyamine comprises a trifunctional polyamine and the polyisocyanate component comprises one or more trifunctional polyisocyanates. In still other embodiments, the shell wall is formed by the reaction between a polyisocyanate or polyisocyanate mixture having at least an average of 2.5 reactive groups per molecule and a polyamine having an average of at least 3 reactive groups per molecule. Moreover, it is advantageous to select the concentrations of the polyamine component and the polyisocyanate component such that the polyisocyanate component reacts substantially completely to form the polyurea polymer. The complete reaction of the polyisocyanate component increases the percentage of crosslinking between the polyurea polymers formed in the reaction, thereby providing structural stability to the shell wall. These factors, i.e., the ratio of the weight of the core material to the weight of the shell wall components, the average particle size of the herbicidal microcapsules, the degree of crosslinking, etc., can be selected to affect the release rate profile of the herbicidal microcapsule population, thereby making it possible to prepare herbicidal microcapsules that enhance crop safety in a balanced manner and are still effective for weed control.

[0043] Microencapsulated acetanilide can be prepared by the method described in U.S. Publication No. 2010 / 0248963. Specifically, the method comprises encapsulating a core material comprising an acetanilide herbicide within a shell wall that is formed by reacting a polyamine component and a polyisocyanate in a reaction medium at a concentration such that the reaction medium contains a molar equivalent excess of amine groups compared to isocyanate groups. That is, the molar equivalent ratio of amine equivalents to isocyanate equivalents for preparing the microcapsule shell wall is greater than 1:1. For example, a molar equivalent ratio of at least 1.01:1 or at least about 1.05:1 is used to ensure complete reaction of the isocyanate. The ratio of the amine molar equivalents contained in the polyamine component to the isocyanate molar equivalents contained in the polyisocyanate component can be from 1.01:1 to about 1.7:1, 1.01:1 to about 1.6:1, 1.01:1 to about 1.5:1, 1.01:1 to about 1.4:1, 1.01:1 to about 1.3:1, 1.05:1 to about 1.7:1, 1.05:1 to about 1.6:1, 1.05:1 to about 1.5:1, 1.05:1 to about 1.4:1 or 1.05:1 to about 1.3:1.

[0044] The molar equivalent ratio of amine molar equivalents to isocyanate molar equivalents is calculated according to the following equation:

[0045]

[0046] In the above equation (1), the amine molar equivalent is calculated according to the following equation:

[0047] Molar equivalent = Σ (weight of polyamine / equivalent).

[0048] In the above equation (1), the isocyanate molar equivalent is calculated according to the following equation:

[0049] Isocyanate molar equivalent = Σ (weight of polyisocyanate / equivalent).

[0050] The equivalent is usually calculated by dividing the molecular weight in grams per mole by the number of functional groups per molecule. For some molecules, such as triethylenetetramine ("TETA") and dicyclohexylmethane-4,4'-diisocyanate ("DES W"), the equivalent is equal to the molecular weight divided by the number of functional groups per molecule. For example, TETA has a molecular weight of 146.23 g / mol and 4 amine groups. Thus, the equivalent is 36.6 g / mol. This calculation is usually correct, but for some materials, the actual equivalent may differ from the calculated equivalent. In some components, for example, in the biuret-containing adduct of hexamethylene-1,6-diisocyanate (i.e., the trimer), due to, for example, incomplete reaction, the equivalent of the commercially available material differs from the theoretical equivalent. The theoretical equivalent of the biuret-containing adduct of hexamethylene-1,6-diisocyanate (i.e., the trimer) is 159.5 g / mol. For the trimer of hexamethylene-1,6-diisocyanate ("DES N3200"), the actual equivalent of the commercially available product is approximately 183 g / mol. The actual equivalent is used in the above calculations. The actual equivalent can be obtained from the manufacturer or by titration with a suitable reactant by methods known in the art. The symbol Σ in the calculation of the amine molar equivalent means that the amine molar equivalent includes the sum of the amine molar equivalents of all polyamines in the reaction medium. Similarly, the symbol Σ in the calculation of the isocyanate molar equivalent means that the isocyanate molar equivalent includes the sum of the isocyanate molar equivalents of all polyisocyanates in the reaction medium.

[0051] As reported in U.S. Publication No. 2010 / 0248963, without being bound by any particular theory, it is believed that the combination of increased particle size and shell characteristics caused by an excess of unreacted amine groups significantly reduces the release rate, in this case the amount of herbicide to which crop plants are exposed after application, thereby providing enhanced crop safety and minimized crop plant damage. Without being bound by any particular theory, it is believed that a greater excess of amine groups results in a substantial number of unreacted amine functional groups, thereby providing a shell with a large number of uncrosslinked amine functional groups. It is believed that the resulting shell wall is flexible and resistant to rupture, such that the amount of herbicide to which crop plants are initially exposed after application of the microcapsule-containing herbicidal formulation is reduced. It is further believed that the unreacted amine groups can reduce the number of fissures or cracks in the shell wall, thereby reducing the leakage and flow of herbicide from the core through the shell wall.

[0052] Thus, in various embodiments, the molar concentration of amine groups from the polyamine component and the molar concentration of isocyanate groups from the at least one polyisocyanate (i.e., one polyisocyanate, a blend of two polyisocyanates, a blend of three polyisocyanates, etc.) in the reaction medium are such that the ratio of the concentration of amine molar equivalents to the concentration of isocyanate molar equivalents is at least about 1.1:1. In various embodiments, the molar equivalent ratio of amine molar equivalents to isocyanate molar equivalents can be at least about 1.15:1, or even at least about 1.20:1. In some embodiments, the molar equivalent ratio is less than about 1.7:1, less than about 1.6:1, less than about 1.5:1, less than about 1.4:1 or even less than about 1.3:1. In various embodiments, the molar equivalent ratio of amine molar equivalents to isocyanate molar equivalents in the polymerization medium is from 1.1:1 to about 1.7:1, 1.1:1 to about 1.6:1, 1.1:1 to about 1.5:1, 1.1:1 to about 1.4:1, 1.1:1 to about 1.3:1, about 1.15:1 to about 1.7:1, about 1.15:1 to about 1.6:1, about 1.15:1 to about 1.5:1, about 1.15:1 to about 1.4:1, about 1.15:1 to about 1.3:1, 1.2:1 to about 1.7:1, 1.2:1 to about 1.6:1, 1.2:1 to about 1.5:1, 1.2:1 to about 1.4:1 or 1.2:1 to about 1.3:1. Examples of typical ratios include 1.1:1, 1.15:1, 1.2:1, 1.25:1, 1.3:1, 1.35:1, 1.4:1, 1.45:1 and 1.5:1.

[0053] Typically, microcapsules can be characterized as having an average particle size of at least about 2, 3, 4, 5, 6, 7, 8, 9, or 10 μm. For example, the microcapsules can have an average particle size range of from about 2 μm to about 15 μm, from about 2 μm to about 12 μm, or from about 6 μm to about 15 μm. The capsules or microcapsules are substantially spherical such that the average lateral dimension defined by any point on the surface of the microcapsule to a point on the opposite side of the microcapsule is substantially the diameter of the microcapsule. The average particle size of the microcapsules can be determined by measuring the particle size of a representative sample with a laser scattering particle size analyzer known to those skilled in the art. An example of a particle size analyzer is the Coulter LS particle size analyzer.

[0054] Further, according to the method described in U.S. Publication No. 2010 / 0248963, encapsulated acetanilide can be prepared, wherein the particles (i.e., capsules or microcapsules) are characterized as having an average particle size of at least about 7 μm. The microencapsulated acetanilide particles can be characterized as having an average particle size of at least about 8 μm, at least about 9 μm, or at least about 10 μm. In various embodiments, the encapsulated acetanilide particles are characterized as having an average particle size of less than about 15 μm or less than 12 μm. In its view, the microencapsulated acetanilide can be characterized as having an average particle size of from about 7 μm to about 15 μm, from about 7 μm to about 12 μm, from about 8 μm to about 12 μm, or from about 9 μm to about 12 μm. In a particularly preferred embodiment, the range varies from 9 μm to about 11 μm.

[0055] In certain embodiments, the core material may also comprise one or more compounds for release (e.g., acetanilides and one or more additives that are compatible therewith and enhance their biological efficacy against weeds and / or reduce crop injury). For example, in some embodiments, the core material optionally comprises a safener. Suitable safeners include, for example, furilazole ((RS)-3-(dichloroacetyl)-5-(2-furyl)-2,2-dimethyl-1,3-oxazolidine 95%), available from Monsanto Company; AD 67 (4-(dichloroacetyl)-1-oxa-4-azaspiro[4,5]decane); benoxacor (CGA154281, (RS)-4-dichloroacetyl-3,4-dihydro-3-methyl-2H-1,4-benzoxazine); cloquintocet-mexyl (CGA184927, (5-chloroquinolin-8-yloxy)acetic acid); cyometrinil (CGA43089, (Z)-cyanomethoxyimino(phenyl)acetonitrile); cyprosulfamide (N-[4-(cyclopropylcarbamoyl)phenylsulfonyl]-o-anisamide); dichlormid (DDCA, R25788, N,N-diallyl-2,2-dichloroacetanilide); dicyclonon ((RS)-1-dichloroacetyl-3,3,8a-trimethylperhydro-pyrrolo[1,2-a]pyrimidin-6-one); dietholate (O,O-diethyl O-phenyl phosphorothioate); fenchlorazole-ethyl (HOE 70542, 1-(2,4-dichlorophenyl)-5-trichloromethyl-1H-1,2,4-triazole-3-carboxylic acid); fenclorim (CGA123407 4,6-dichloro-2-phenylpyrimidine); flurazole (benzyl 2-chloro-4-trifluoromethyl-1,3-thiazole-5-carboxylate); fluxofenim (CGA133205, 4′-chloro-2,2,2-trifluoroacetophenone (EZ)-O-(1,3-dioxolan-2-yl)methyl oxime); isoxadifen (4,5-dihydro-5,5-diphenyl-1,2-oxazole-3-carboxylic acid); mefenpyr ((RS)-1-(2,4-dichlorophenyl)-5-methyl-2-pyrazoline-3,5-dicarboxylic acid); mephenate (4-chlorophenylmethylcarbamate); MG 191; naphthalic anhydride; oxabetrinil (CGA92194 and (Z)-1,3-dioxolan-2-ylmethoxyimino(phenyl)acetonitrile).

[0056] Generally, encapsulated acetanilide herbicide granules contain a water-insoluble agrochemical-containing core material encapsulated by a polyurea shell wall that is preferably substantially non-microporous, such that release of the core material occurs by a molecular diffusion mechanism, which is distinct from a flow mechanism through pores or cracks in the polyurea shell wall. As noted herein, the shell wall may preferably comprise a polyurea product polymerized from one or more polyisocyanates and a primary polyamine (and optionally a secondary polyamine). Typically, the encapsulated acetanilide herbicide granules (e.g., capsules or microcapsules) are dispersed in a liquid medium, preferably water. The acetanilide herbicide loading of the encapsulated acetanilide herbicide dispersion is from about 5% to about 50% by weight of active ingredient, such as 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or even 50% by weight of active ingredient. A herbicidal thick aqueous solution is prepared by combining an aqueous dispersion of the encapsulated acetanilide herbicide granules and a PPO inhibitor component.

[0057] The water-soluble PPO inhibitor component can be prepared by adding an acidic herbicide (e.g., fomesafen) to water and then adding an appropriate base (e.g., sodium hydroxide) with stirring to prepare a water-soluble PPO inhibitor salt solution. The resulting solution is then mixed with the encapsulated acetanilide herbicide dispersion to form a herbicidal thick aqueous solution composition.

[0058] The encapsulated acetanilide herbicide dispersion and herbicidal thick aqueous solution composition of the present invention may contain one or more additives. For example, in various embodiments, the acetanilide herbicide dispersion and / or the herbicidal thick aqueous solution composition contains one or more of the following additives: dispersants, surfactants, thickeners, structure breakers, density modifiers, antifreeze agents, anti-scaling agents, drift control agents, preservatives, and defoamers.

[0059] In various aspects, the encapsulated acetanilide herbicide dispersion and (therefore) the herbicidal thick aqueous solution composition of the present invention contain one or more thickeners. Generally, thickeners are used to retard the sedimentation process by increasing the viscosity of the aqueous phase. In various embodiments, pseudoplastic thickeners (i.e., shear-thinning thickeners) are preferred because they reduce the dispersion viscosity during pumping, which facilitates economical application to farmland and uniform coverage of the dispersion using equipment commonly used for this purpose. Several examples of useful pseudoplastic thickeners include water-soluble, guar or xanthan-based gums (e.g., Kelzan from CP Kelco), cellulose ethers (e.g., ETHOCEL from Dow), and modified cellulose plastics and polymers (e.g., Aqualon thickeners from Hercules). In some embodiments, the pseudoplastic thickener comprises a water-soluble gum selected from the group consisting of guar gum, xanthan gum, and combinations thereof. In certain embodiments, the pseudoplastic thickener comprises xanthan gum.

[0060] Some dispersions of encapsulated acetanilide herbicides known in the art contain no more than about 500 ppm or about 600 ppm of a thickening agent. Above this concentration range, the viscosity of the dispersion increases to a point where it can cause poor pumpability and possible gelation of the encapsulated acetanilide herbicide particles. However, contrary to this understanding, it has surprisingly been found that when formulating a herbicidal aqueous concentrate containing an encapsulated acetanilide herbicide (e.g., microcapsules) and a PPO inhibitor (e.g., a water-soluble PPO), the thickening agent concentration is significantly above this critical maximum in order to provide a stable composition (i.e., a composition having a viscosity high enough to avoid significant phase separation). Thus, in various embodiments, the herbicidal aqueous concentrate composition contains at least about 750 ppm, at least about 800 ppm, at least about 850 ppm, at least about 900 ppm, or at least about 950 ppm of a thickening agent (e.g., a pseudoplastic thickening agent), based on the total weight of the composition. Generally, the concentration of the thickening agent is less than about 2000 ppm, less than about 1800 ppm, less than about 1500 ppm, less than about 1300 ppm, or less than about 1200 ppm. In some embodiments, the concentration of the thickening agent is from about 800 ppm to about 1500 ppm or from about 900 ppm to about 1200 ppm.

[0061] In certain embodiments, as measured with a Haake Rotovisco viscometer and with a spindle rotating at about 45 rpm at about 10 °C, the viscosity of the encapsulated acetanilide herbicide dispersion after formulation can preferably range from about 100 cps to about 600 cps. More preferably, the viscosity range can be from about 100 cps to about 300 cps.

[0062] The dispersion is present during the interfacial polymerization reaction for preparing acetanilide microcapsules and serves to inhibit aggregation and sedimentation of the microcapsules. Thus, in various embodiments, the encapsulated acetanilide herbicide dispersion and (therefore) the herbicidal aqueous concentrate composition of the present invention contain one or more dispersants. Low molecular weight dispersants can dissolve the acetanilide capsules or the microcapsule shell walls, especially in the early stages of their formation, causing gelation problems. Thus, in some embodiments, the dispersant has a relatively high molecular weight, at least about 1.5 kg / mol, more preferably at least about 3 kg / mol and still more preferably at least about 5, 10 or even 15 kg / mol. In some embodiments, the molecular weight range can be from about 5 kg / mol to about 50 kg / mol. The dispersant can also be nonionic or anionic. Examples of high molecular weight, anionic polymeric dispersants are sodium salts of polymeric naphthalene sulfonates such as Invalon (formerly Irgasol, Huntsman Chemicals). Other useful dispersants as previously mentioned include gelatin, casein, ammonium caseinate, polyvinyl alcohol, alkylated polyvinylpyrrolidone polymers, maleic anhydride-methyl vinyl ether copolymers, styrene-maleic anhydride copolymers, maleic acid-butadiene and diisobutylene copolymers, sodium and calcium lignosulfonates, sulfonated naphthalene-formaldehyde condensates, modified starches and modified cellulose plastics such as hydroxyethyl or hydroxypropyl cellulose and sodium carboxymethyl cellulose.

[0063] It has been found that regulating the dispersant concentration is important for obtaining a stable concentrate. Surprisingly, it has been observed that when a stable dispersion of an encapsulated acetanilide herbicide is mixed with an aqueous concentrate of a PPO inhibitor, the resulting mixture is unstable and phase separation occurs. Thus, it is expected that simply mixing commercial encapsulated acetanilide concentrates and PPO inhibitor concentrates will not provide a stable concentrated mixture. Some stable formulations of encapsulated acetanilide herbicides are known to contain about 3 wt% of the total dispersant. According to the present invention, to provide a stable herbicidal aqueous concentrate composition, the total dispersant concentration is increased to at least about 3.5 wt% or at least about 3.75 wt% (e.g., from about 3.5 wt% to about 5 wt% or from about 3.75 wt% to about 4.5 wt%).

[0064] To enhance the storage stability of aqueous encapsulated acetanilide herbicide granules and prevent gelation, especially after storage in high-temperature environments, the liquid dispersion and (therefore) the herbicide concentrate composition preferably include a structure breaker. Gelation is an important consideration for some encapsulated acetanilide herbicide dispersions because the process is difficult, if not impossible, to reverse and can render the product unsuitable for dilution and application. Thus, in various embodiments, the encapsulated acetanilide herbicide dispersion and (therefore) the herbicide concentrate composition of the present invention include one or more structure breakers. A preferred structure breaker is urea. To prevent gelation, in some embodiments, the concentrated composition includes at least about 4, 5, or 6 wt% and up to about 20 wt% or up to about 10 wt% (e.g., about 4 wt% to about 10 wt%) of the structure breaker. However, in some embodiments, it has surprisingly been found that when formulating certain herbicide concentrates of the present invention containing encapsulated acetanilide herbicides (e.g., microcapsules) and PPO inhibitors (e.g., water-soluble PPO), the concentration of the structure breaker does not exceed about 3.5 wt%. Generally, at least about 1 wt%, at least about 2 wt%, or at least about 2.5 wt% of the structure breaker is required in these and other embodiments.

[0065] Adjusting the density of the aqueous phase to achieve an average weight per volume of microcapsules also slows the settling process. In addition to its primary use, many additives can increase the density of the aqueous phase. Further increases can be achieved by adding density modifiers such as sodium chloride and ethylene glycol. A preferred density modifier is glycerol. The herbicide concentrate composition can have a density modifier concentration of at least about 4 wt% but not exceeding about 10 wt%. In various embodiments, the density modifier concentration is from about 5 wt% to about 10 wt%, from about 5 wt% to about 8 wt%, from about 5 wt% to about 6.5 wt%, from about 5.5 wt% to about 7 wt%, or from about 5.5 wt% to about 6.5 wt%.

[0066] In addition to its structure-breaking properties, urea also acts as a density modifier. In embodiments where urea is included as a structure breaker, the total concentration of urea and density modifiers other than urea (e.g., glycerol) is from about 6 wt% to about 10 wt%, from about 6.5 wt% to about 10 wt%, from about 7 wt% to about 10 wt%, from about 7.5 wt% to about 9 wt%, or from about 8 wt% to about 9 wt%. In these embodiments, it has been found that this combination of urea and density modifiers (e.g., glycerol) provides a stable herbicide concentrate composition that resists gelation and settling after storage, even though the concentrations of these components are generally lower than those typically required to prepare a stable dispersion of encapsulated acetanilide herbicides.

[0067] In some cases, the weight - volume ratio of the encapsulated acetanilide herbicide granules of a preferred size approximates the density of the core material, where the density of the core material is from about 1.05 to about 1.5 g / cm 3 . Thus, in various embodiments, the density of the aqueous phase of the concentrate is formulated to be within the average weight - volume ratio of the encapsulated acetanilide herbicide granules of about 0.2 g / cm 3 .

[0068] A surfactant may optionally be included in the herbicidal aqueous concentrate composition. Suitable surfactants are selected from the group consisting of non - ionic, cationic, anionic, and mixtures thereof. Examples of surfactants suitable for the practice of the present invention include, but are not limited to: alkoxylated tertiary ether amines (such as TOMAH E - series surfactants); alkoxylated quaternary ether amines (such as TOMAH Q - series surfactants); alkoxylated amine oxides (such as TOMAH AO - series surfactants); alkoxylated tertiary amine oxides (such as AROMOX series surfactants); alkoxylated tertiary amine surfactants (such as ETHOMEEN T and C series surfactants); alkoxylated quaternary amines (such as ETHOQUAD T and C series surfactants); alkyl sulfates, alkyl ether sulfates, and alkyl aryl ether sulfates (such as WITCOLATE series surfactants); alkyl sulfonates, alkyl ether sulfonates, and alkyl aryl ether sulfonates (such as WITCONATE series surfactants); alkoxylated phosphates and diesters (such as PHOSPHOLAN series surfactants); alkyl polysaccharides (such as AGRIMUL PG series surfactants); alkoxylated alcohols (such as BRIJ or HETOXOL series surfactants); and mixtures thereof.

[0069] An anti - caking agent facilitates redispersion of the encapsulated acetanilide herbicide granules (e.g., microcapsules) after agitation of a formulation in which the granules have settled. Microcrystalline cellulose materials such as LATTICE from FMC are effective as anti - caking agents. Other suitable anti - caking agents are, for example, clays, silica, insoluble starch granules, and insoluble metal oxides (such as alumina or iron oxide). In at least some embodiments, anti - caking agents that avoid changing the pH of the dispersion are preferred.

[0070] The pH range of the herbicidal aqueous concentrate composition can be from about 7 to about 9 in order to minimize eye irritation to those persons who may come into contact with the composition during handling or application. However, if the components of the formulated dispersion are pH - sensitive, a buffer such as disodium phosphate can be used to maintain the pH within the range where the components are most effective. Thus, a pH buffer such as citric acid monohydrate can be particularly helpful in maximizing the effectiveness of protective colloids such as SOKALAN CP9 during the preparation of the encapsulated acetanilide herbicide in some systems.

[0071] Other useful additives include, for example, biocides or preservatives (e.g., PROXEL available from Avecia), antifreeze agents, and defoamers (such as Antifoam SE23 from Wacker Silicones Corp. or AGNIQUE DFM-111S available from BASF).

[0072] The herbicidal aqueous concentrate composition of the present invention may comprise a combination of additives. For example, in various embodiments, the herbicidal aqueous concentrate composition comprises a combination of additives including a pseudoplastic thickener (e.g., xanthan gum), urea, glycerol, and a combination of dispersants (e.g., naphthalene sulfonate condensate, maleic acid-olefin copolymer, and ammonium caseinate). In certain embodiments, the herbicidal aqueous concentrate composition comprises a combination of additives including additives in the approximate concentration ranges listed in the following table:

[0073]

[0074] In the preparation of a herbicidal aqueous concentrate composition comprising one or more of the additives mentioned herein, the entire portion of the additives (e.g., thickeners, dispersants, structure breakers, density modifiers, etc.) may be added to the liquid dispersion of the encapsulated acetanilide herbicide prior to combination with the PPO inhibitor component. Optionally, a first portion of the additives may be added during the preparation of the stable liquid dispersion of the encapsulated acetanilide herbicide and a second portion may be added during the preparation of the herbicidal aqueous concentrate composition (i.e., mixing the dispersion of the encapsulated acetanilide herbicide and the PPO inhibitor or its solution).

[0075] According to the present invention, it has been found that the readily extractable acetanilide herbicide in the aqueous phase of the concentrate composition may be from about 0.5% to about 10%, from about 0.5% to about 5%, from about 0.5% to about 2%, from about 0.75% to about 10%, from about 0.75% to about 5%, from about 0.75% to about 2%, from about 1% to about 10%, from about 1% to about 5%, or from about 1% to about 2% by weight of the total acetanilide herbicide. Generally, the concentration of the readily extractable acetanilide herbicide in the microencapsulated concentrate is far less than 0.5 by weight of the total acetanilide herbicide. Without being bound by theory, it is believed that the PPO inhibitor present in the aqueous phase increases the solubility of the acetanilide herbicide (see Example 7) and results in a higher concentration of the readily extractable acetanilide herbicide. The readily extractable acetanilide can be determined by extracting the concentrate composition with a weak solvent such as a fatty hydrocarbon solvent and analyzing the extract. Importantly, it has been found that crop safety and weed control efficiency are not adversely affected by this unexpected result.

[0076] Accordingly, another aspect of the present invention relates to a concentrated aqueous herbicidal composition comprising: microcapsules comprising a core material containing an acetanilide herbicide and a shell wall material encapsulating the core material; an aqueous phase comprising the acetanilide herbicide (uncapsulated acetanilide) and a water-soluble protoporphyrinogen oxidase inhibitor (PPO inhibitor), wherein the total acetanilide herbicide concentration is at least about 25% by weight and the concentration of the acetanilide herbicide in the aqueous phase is from about 0.5% to about 10%, from about 0.5% to about 5%, from about 0.5% to about 2%, from about 0.75% to about 10%, from about 0.75% to about 5%, from about 0.75% to about 2%, from about 1% to about 10%, from about 1% to about 5% or from about 1% to about 2% based on the weight of the total acetanilide herbicide. As noted, the weight ratio of the total acetanilide herbicide to the PPO inhibitor on an acid equivalent (a.e.) basis is from about 1:10 to about 10:1, from about 1:8 to about 8:1, from about 1:6 to about 6:1. In various embodiments, the weight of the acetanilide herbicide is higher than the weight of the PPO inhibitor. Accordingly, the weight ratio of the total acetanilide herbicide to the PPO inhibitor on an acid equivalent basis is from about 2:1 to about 10:1, from about 2:1 to about 8:1, from about 3:1 to about 10:1, from about 3:1 to about 8:1, from about 4:1 to about 10:1, from about 4:1 to about 8:1, from about 5:1 to about 10:1 or from about 5:1 to about 8:1.

[0077] The concentrated aqueous herbicides disclosed herein are useful as controlled-release herbicides. Accordingly, the present invention also relates to a method of applying an application mixture for controlling plant growth, the mixture being a dilution of a concentrated composition. The acetanilide herbicide loading in the application mixture is generally no more than about 5% or is from about 0.1% to about 5% by weight of active ingredient, such as 5%, 4%, 3%, 2%, 1%, 0.5% or 0.1% by weight of active ingredient.

[0078] The application mixture can be applied to the field according to practices known to those skilled in the art. In some embodiments, the application mixture is applied to the soil before or after planting crop plants, but prior to emergence of the crop plants. Because the release characteristics of the encapsulated acetanilide herbicide particles can be adjusted, the timing of the onset of release (or increased release) can be controlled, thereby giving commercially acceptable weed control and a commercially acceptable rate of crop injury.

[0079] The effective amounts of the encapsulated acetanilide herbicides and PPO inhibitors applied to the farmland depend on the characteristics of the herbicides, the release rate of the capsules or microcapsules, the crop to be treated, and environmental conditions, especially soil type and humidity. Generally, the application rate of an acetanilide herbicide, such as acetochlor, is at a level of about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 kilograms of herbicide per hectare, or in a range, such as 0.5 to 10 kilograms per hectare, 0.5 to 10 kilograms per hectare, 0.5 to 5 kilograms per hectare, or 1 to 5 kilograms per hectare. In some embodiments, an application rate of about 0.85 to about 1 kilogram per hectare is preferred for sorghum, rice, and wheat.

[0080] Generally, the application rate of a PPO inhibitor herbicide, such as fomesafen sodium, is at a level of about 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 4, or 5 kilograms per hectare, or in a range, such as 0.1 to 5 kilograms per hectare, 0.5 to 2.5 kilograms per hectare, or 0.5 to 2 kilograms per hectare.

[0081] Preferably, the application mixture of the herbicidal aqueous concentrate is applied to the farmland during a selected time period of the development of the crop plants. In various embodiments of the present invention, the application mixture prepared from the herbicidal aqueous concentrate is applied after the crop plants emerge. For the purposes of the present invention, after the crop plants emerge includes the first emergence from the soil, i.e., "cracking". In some embodiments, the application mixture is applied to the field 1 - 40 days before and / or before emergence (i.e., from planting the crop plants to (but not including) emergence or cracking) of the crop plants in order to provide control of newly emerging monocotyledonous and small-seeded dicotyledonous plant species without significant crop damage. In various embodiments, the application mixture prepared from the herbicidal aqueous concentrate of the present invention is applied before the weeds emerge.

[0082] The application mixture of the herbicidal aqueous concentrate of the present invention is used to control various weeds, that is, plants regarded as obstacles or competitors to commercially important crop plants such as corn, soybean, cotton, dry bean, snap bean, potato, etc. In some embodiments, the application mixture is applied before the weeds germinate (i.e., pre-emergence application). Examples of weeds that can be controlled according to the method of the present invention include but are not limited to Alopecurus pratensis and other weed species of the genus Alopecurus, Echinochloa crus-galli and other weed species of the genus Echinochloa, Digitaria sanguinalis of the genus Digitaria, Trifolium repens, Chenopodium berlandieri, Amaranthus retroflexus and other weed species of the genus Amaranthus, Portulaca oleracea and other weed species of the genus Portulaca, Chenopodium album and other species of the genus Chenopodium, Setaria lutescens and other species of the genus Setaria, Solanum nigrum and other species of the genus Solanum, Lolium multiflorum and other species of the genus Lolium, Brachiaria platyphylla and other species of the genus Brachiaria, Sorghum halepense and other species of the genus Sorghum, Conyza canadensis and other species of the genus Conyza, and Eleusine indica. In some embodiments, the weeds include one or more glyphosate-resistant species, 2,4-D-resistant species, dicamba-resistant species, and / or ALS inhibitor herbicide-resistant species.In some embodiments, glyphosate-resistant weed species are selected from the group consisting of: Amaranthus palmeri, Amaranthus rudis, Ambrosia artemisiifolia, Ambrosia trifida, Conyza bonariensis, Conyza canadensis, Digitaria insularis, Echinochloa colona, Eleusine indica, Euphorbia heterophylla, Lolium multiflorum, Lolium rigidum, Plantago lancelata, Sorghum halepense, and Urochloa panicoides.

[0083] Certain crop plants such as soybeans and cotton are less sensitive to acetanilide herbicides and PPO inhibitors compared to weeds. According to the present invention and based on the experimental evidence to date, it is believed that when an encapsulated acetanilide herbicide is applied to a field before or pre-emergence of crop plants, the controlled release of acetanilide from the encapsulated acetanilide herbicide in combination with crop plants having reduced acetanilide sensitivity enables commercial control of weeds and a commercially acceptable damage rate. This enables the use of the acetanilide herbicide as a seedling growth inhibitor, or optionally the acetanilide herbicide in combination with a PPO inhibitor, in pre-planting and pre-emergence applications of crop plants.

[0084] In some embodiments of the present invention, crop plants include, for example, corn, soybeans, cotton, dry beans, snap beans, and potatoes. Crop plants include hybrid, inbred, and transgenic or genetically modified plants having specific traits or combinations of traits, including but not limited to herbicide tolerance (e.g., resistance to glyphosate, glufosinate, dicamba, sethoxydim, PPO inhibitors, etc.), Bacillus thuringiensis (Bt), high oil, high lysine, high starch, nutrient density, and drought resistance. In some embodiments, crop plants are tolerant to organophosphate herbicides, acetolactate synthase (ALS) or acetohydroxyacid synthase (AHAS) inhibitor herbicides, synthetic auxin herbicides, and / or acetyl-CoA carboxylase (ACC enzyme) inhibitor herbicides. In other embodiments, crop plants are tolerant to glyphosate, dicamba, 2,4-D, MCPA, quizalofop, glufosinate, and / or diclofop-methyl. In other embodiments, crop plants are tolerant to glyphosate and / or dicamba. In some embodiments of the present invention, crop plants are tolerant to glyphosate and / or glufosinate. In some other embodiments, crop plants are tolerant to glyphosate, glufosinate, and dicamba. In these and other embodiments, crop plants are tolerant to PPO inhibitors.

[0085] Particularly preferred crop species are cotton and soybeans. In embodiments where the crop is cotton, it is preferred to apply the application mixture at the time of planting until before crop emergence, before crop planting (e.g., 1 - 4 weeks before planting the crop) and / or after crop emergence (e.g., using a shielded sprayer to apply the application mixture away from the crop). In embodiments where the crop is soybeans, it is preferred to apply the application mixture at the time of planting until before crop emergence, before crop planting (e.g., 1 - 4 weeks before planting the crop) and / or after crop emergence.

[0086] Examples

[0087] The following non-limiting examples are provided to further illustrate the present invention.

[0088] Example 1

[0089] Prepare a concentrated aqueous herbicide composition according to the protocol described in this example.

[0090] Prepare a dispersion of microencapsulated acetochlor as follows. Prepare the internal phase with the components and amounts shown in Table 1 - 1. Percentages represent the approximate weight percentages of each component in the final concentrated aqueous herbicide composition.

[0091] Table 1 - 1. Internal phase components

[0092]

[0093] To prepare the internal phase of the acetochlor microcapsules, acetochlor is loaded into a mixing container. Next, the solvent ISOPAR M is loaded into the mixing container, followed by the addition of DESMODUR N 3215 polyisocyanate. The solution is stirred to obtain a clear and homogeneous solution. The solution can be sealed in the mixing container and stored until needed. Before use, the mixture is heated to 50 °C in an oven.

[0094] Prepare the external aqueous phase containing the components and amounts shown in Table 1-2:

[0095] Table 1-2. External phase components

[0096]

[0097] To prepare the external phase, water and the remaining external phase components except TETA are loaded into a mixing container. The solution is stirred to obtain a clear and homogeneous solution. The solution can be sealed in the mixing container and stored until needed. Before use, the mixture is heated to 50 °C in an oven.

[0098] First, the external phase (without TETA) is loaded into a Waring blender cup that has been preheated to 50 °C. A commercial Waring blender (Waring Products Division, Dynamics Corporation of America, New Hartford, Conn., Blender 700) is powered by a 0 to 120 volt variable autotransformer. The mixing speed of the blender is changed by controlling the power of the blender. The internal phase is added to the external phase at 16-second intervals and mixing is continued to obtain an emulsion.

[0099] To initiate the polymerization and encapsulation of the internal phase, TETA is added to the emulsion in about 5 seconds. Then the blender speed is reduced to a speed that produces only a vortex for about 5 to 15 minutes. Then the emulsion is transferred to a hot plate and stirred. The reaction vessel is covered and maintained at about 50 °C for about two hours, and two hours has been found to be sufficient time for the isocyanate to react substantially completely.

[0100] Then the capsule slurry is cooled to near room temperature. The components shown in Table 1-3 except the buffer were premixed previously with a high-speed mixer (Waring blender or Cowles Dissolver). Then the resulting stabilizer premix is added to the capsule slurry to stabilize the dispersion of the microcapsules. Finally, the buffer is added and the mixture is stirred for at least 15 minutes until visually homogeneous.

[0101] Table 1-3. Stabilizer components

[0102]

[0103] Prepare this dispersion of acetochlor microcapsules to have an excess molar equivalent ratio of amine molar equivalent to isocyanate molar equivalent and a herbicide to wall component ratio. TETA has an approximate molar equivalent of 36.6 g / mol. DESMODUR N3215 has an approximate molar equivalent of 181 g / mol. The average particle size of the acetochlor microcapsules is about 10 microns.

[0104] Mix the dispersion of acetochlor microcapsules with a solution of sodium fomesafen. A stable concentrate that does not phase separate is formed. The complete aqueous concentrate composition is provided below.

[0105] Table 1-4. Final herbicidal aqueous concentrate composition 1

[0106]

[0107]

[0108] Example 2

[0109] Additional herbicidal aqueous concentrate compositions are prepared according to the protocol described in Example 1. The composition of each aqueous concentrate is provided in the table below.

[0110] Table 2-1. Final herbicidal aqueous concentrate composition 2

[0111]

[0112]

[0113] Table 2-2. Final herbicidal aqueous concentrate composition 3

[0114]

[0115] Table 2-3. Final herbicidal aqueous concentrate composition 4

[0116]

[0117]

[0118] Table 2-4. Final herbicidal aqueous concentrate composition 5

[0119]

[0120] Table 2-5. Final herbicidal aqueous concentrate composition 6

[0121]

[0122]

[0123] Table 2-6. Final concentrated aqueous herbicide composition 7

[0124]

[0125] Table 2-7. Final concentrated aqueous herbicide composition 8

[0126]

[0127] Example 3

[0128] Measure various properties of the concentrated aqueous herbicide compositions prepared in Examples 1 and 2. The results of these measurements are provided in the following table. The readily extractable acetochlor was determined by extracting the concentrated composition with a weak solvent such as a fatty hydrocarbon solvent and analyzing the extract. The particle size was measured using a Coulter LS particle size analyzer. The viscosity was measured using a Haake Rotovisco viscometer with the spindle rotating at approximately 45 rpm at approximately 10°C.

[0129] Table 3-1. Properties of the herbicide concentrated composition

[0130]

[0131] Example 4

[0132] The concentrated aqueous herbicide compositions prepared in Examples 1 and 2 were subjected to a thermal aging test to study the effect of long-term storage on the viscosity of the compositions. Samples of each herbicide concentrated composition were stored at 40°C for 8 weeks. Gelation was not observed in any of the concentrated compositions.

[0133] Example 5

[0134] A concentrated composition of WARRANT, a commercially available microencapsulated acetochlor available from Monsanto Co., St. Louis, Missouri, was mixed with a commercially available sodium fomesafen concentrated composition. The following table provides the composition of the mixture. Combining these two compositions produced an unstable mixture with phase separation.

[0135] Table 5-1. Mixture of WARRANT and fomesafen concentrate

[0136]

[0137] Example 6

[0138] A series of field trials were conducted at multiple locations. The soil structures at these sites ranged from silt loam, silt clay loam to sandy silt loam and sandy loam. The purpose of the experiment was to evaluate the weed control efficacy and residual activity length of each individual herbicide compared to herbicide combinations. The experiment was conducted in a randomized complete block design. Four replicates were completed for each treatment. The application time was pre-emergence of the weeds, and the treatments were applied using a backpack or tractor-mounted sprayer. The application mixture prepared from the concentrated composition 7 described in Example 2 was applied at a rate of 1.363 lb active ingredient (a.i.) per acre under field conditions. For comparison, field trials were also conducted with a mixture of fomesafen and WARRANT.

[0139] Four weeks after treatment (WAT), the percentage of weed control by weed species was observed. Weed control was determined as the percentage compared to untreated plants after a standard procedure, where the visual assessment of plant mortality and growth decline was conducted by personnel specifically trained to conduct such assessments. In the field trials, results were recorded for 16 broadleaf and 7 narrowleaf weed species. These included ABUTH (Abutilon theophrasti (velvetleaf)) in 9 trials; AMATA / AMAPA (Amaranthus palmeri / Amaranthus hybridus), glyphosate-resistant (GR) AMAPA / AMATA, IPOSS (Ipomoea sps. (morningglory sps.)), and ECHCG (Echinochloa sps.) in 5 trials; DIGSS (Digitaria sanguinalis) in 4 trials; CASOB (Cassia obtusifolia), CHEAL (Chenopodium album), and AMBEL (Ambrosia artemisiifolia) in 3 trials; POROL (Portulaca oleracea), MOLVE (Mollugo verticillata), SETFA (Setaria faberi), and SORHA (Sorghum halepense (johnsongrass)) in 2 trials; and ACCOS (Acalypha australis), EPHSS (Euphorbia sps.), HIBTR (Hibiscus trionum (venicemallow)), SIDSP (Sida acuta), BRASS (Brachiaria platyphylla), SORSS (Sorghum bicolor), and PESGL (Pennisetum glaucum) in 1 trial. The results of the field trials are presented in Tables 6-1 and 6-2. The mean percentage of control and standard error were calculated by the least squares method. A summary of the results 4 weeks after treatment for a second field trial with similar weed species is presented in Table 6-3.

[0140] Table 6-1. Weed Species Control of Acetochlor, Fomesafen, and Concentrate No. 7 in Field Trial 1

[0141]

[0142] Table 6-2. Summary of Results of Field Experiment 1

[0143]

[0144]

[0145] Table 6-2. Summary of Results of Field Experiment 2

[0146]

[0147] Example 7

[0148] In this example, the effect of fomesafen on the stability of acetochlor was measured at different fomesafen concentrations. The results are shown in Table 7-1.

[0149] Table 7-1. Solubility of Acetochlor in Fomesafen Solution

[0150]

[0151] When introducing elements of the present invention or its preferred embodiments, the articles "a", "an", "the" and "said" are intended to mean that there is one or more elements. The terms "comprising", "including" and "having" are intended to be inclusive and mean that additional elements may exist in addition to the listed elements.

[0152] In view of the above, it can be seen that several objects of the present invention have been achieved and other advantageous results have been obtained. Since various changes can be made to the above compositions and methods without departing from the scope of the present invention, all the content contained in the above description is intended to be construed in an illustrative rather than a limiting sense.

[0153] The present invention has been described in detail. It is obvious that modifications and changes can be made without departing from the scope of the present invention as defined in the appended claims.

Claims

1. A concentrated aqueous herbicide composition, comprising: Microcapsules containing an acetanilide herbicide, the acetanilide herbicide comprising acetochlor, wherein the concentration of the acetanilide herbicide in the composition by active ingredient is at least 25% by weight; A water-soluble protoporphyrinogen oxidase inhibitor, i.e., a PPO inhibitor, which comprises fomesafen; A pseudoplastic thickener at 900 ppm to 1200 ppm based on the total weight of the composition, wherein the pseudoplastic thickener comprises a water-soluble gum selected from the group consisting of guar gum, xanthan gum, and combinations thereof; A structure breaker at a concentration of at least 1% by weight and not exceeding 3.5% by weight, wherein the structure breaker comprises urea; and A density regulator, wherein the total concentration of the structure breaker and the density regulator is 7% by weight to 10% by weight, and wherein the weight ratio of the total acetanilide herbicide to the PPO inhibitor by acid equivalent is 1:10 to 10:

1.

2. The concentrated aqueous herbicide composition according to claim 1, wherein the pseudoplastic thickener comprises xanthan gum.

3. The concentrated aqueous herbicide composition according to claim 1, wherein the weight ratio of the total acetanilide herbicide to the PPO inhibitor is 1:8 to 8:

1.

4. The concentrated aqueous herbicide composition according to claim 1, wherein the concentration of the acetanilide herbicide in the aqueous phase is 0.5% to 10% of the total weight of the acetanilide herbicide.

5. The concentrated aqueous herbicide composition according to claim 1, wherein the total concentration of the structure breaker and the density regulator is 7.5% by weight to 9% by weight, or 8% by weight to 9% by weight.

6. The concentrated aqueous herbicide composition according to claim 5, wherein the density regulator comprises glycerol.

7. The concentrated aqueous herbicide composition according to claim 1, wherein the concentration of the structure breaker is at least 2% by weight and not exceeding 3.5% by weight or at least 2.5% by weight and not exceeding 3.5% by weight.

8. The concentrated aqueous herbicide composition according to claim 1, wherein the pseudoplastic thickener comprises guar gum.

9. The concentrated aqueous herbicide composition according to claim 8, wherein the weight ratio of the total acetanilide herbicide to the PPO inhibitor is 1:8 to 8:

1.

10. The concentrated aqueous herbicide composition according to claim 8, wherein the concentration of the acetanilide herbicide in the aqueous phase is 0.5% to 10% of the total weight of the acetanilide herbicide.

11. A concentrated aqueous herbicide composition, comprising: Microcapsules comprising a core material containing an acetanilide herbicide and a shell wall material encapsulating the core material, the acetanilide herbicide comprising acetochlor; and An aqueous phase comprising the acetanilide herbicide containing acetochlor and a water-soluble protoporphyrinogen oxidase inhibitor, i.e., a PPO inhibitor, the PPO inhibitor comprising fomesafen, wherein the total concentration of the acetanilide herbicide in the composition by active ingredient is at least 25% by weight; the weight ratio of the total acetanilide herbicide to the PPO inhibitor by acid equivalent is 1:10 to 10:1; and the concentration of the acetanilide herbicide in the aqueous phase is 0.5% to 10% of the total weight of the acetanilide herbicide, and the composition further comprises: A pseudoplastic thickener at a concentration of 900 ppm to 1200 ppm, wherein the pseudoplastic thickener comprises a water-soluble gum selected from the group consisting of guar gum, xanthan gum, and combinations thereof; A structure breaker at a concentration of at least 1 wt% and not exceeding 3.5 wt%, wherein the structure breaker comprises urea; and A density regulator, wherein the total concentration of the structure breaker and the density regulator is 7 wt% to 10 wt%.

12. The herbicidal aqueous concentrate composition according to claim 11, wherein the pseudoplastic thickener comprises xanthan gum.

13. The herbicidal aqueous concentrate composition according to claim 11 or 12, wherein the density regulator comprises glycerol.

14. The herbicidal aqueous concentrate composition according to claim 11 or 12, wherein the total concentration of the structure breaker and the density regulator is 7.5 wt% to 9 wt%, or 8 wt% to 9 wt%.

15. The herbicidal aqueous concentrate composition according to claim 1 or 11, wherein the concentration of the acetanilide herbicide in the composition is at least 30 wt% or at least 35 wt% based on the active ingredient.

16. The herbicidal aqueous concentrate composition according to claim 1 or 11, wherein the concentration of the acetanilide herbicide in the composition is 25 wt% to 40 wt%, 25 wt% to 35 wt%, 30 wt% to 40 wt%, or 30 wt% to 35 wt% based on the active ingredient.

17. The herbicidal aqueous concentrate composition according to claim 1 or 11, wherein the weight ratio of the total acetanilide herbicide to the PPO inhibitor is 1:8 to 8:1, 1:6 to 6:1 based on acid equivalents.

18. The herbicidal aqueous concentrate composition according to claim 1 or 11, wherein the weight of the acetanilide herbicide is greater than the weight of the PPO inhibitor based on acid equivalents.

19. The herbicidal aqueous concentrate composition according to claim 18, wherein the weight ratio of the total acetanilide herbicide to the PPO inhibitor is 2:1 to 10:1, 2:1 to 8:1, 3:1 to 10:1, 3:1 to 8:1, 4:1 to 10:1, 4:1 to 8:1, 5:1 to 10:1, or 5:1 to 8:1 based on acid equivalents.

20. The herbicidal aqueous concentrate composition according to claim 1 or 11, wherein the concentration of the PPO inhibitor is at least 2 wt%, at least 4 wt%, at least 5 wt%, at least 6 wt%, or at least 8 wt% based on the active ingredient.

21. The herbicidal aqueous concentrate composition according to claim 1 or 11, wherein the concentration of the PPO inhibitor is 2 wt% to 20 wt%, 4 wt% to 20 wt%, 5 wt% to 20 wt%, 5 wt% to 15 wt%, 5 wt% to 10 wt%, 6 wt% to 15 wt%, or 6 wt% to 10 wt% based on the active ingredient.

22. The herbicidal aqueous concentrate composition according to claim 1 or 11, wherein the microcapsule containing the acetanilide herbicide comprises a polyurea shell wall.

23. The herbicidal aqueous concentrate composition according to claim 22, wherein the polyurea shell wall is formed in a polymerization medium by a polymerization reaction to form the polyurea between a polyisocyanate component containing a polyisocyanate or a mixture of polyisocyanates and a polyamine component containing a polyamine or a mixture of polyamines.

24. The herbicidal aqueous concentrate composition according to claim 23, wherein the polyisocyanate component contains an aliphatic polyisocyanate.

25. The herbicidal aqueous concentrate composition according to claim 23 or 24, wherein the ratio of the amine molar equivalent contained in the polyamine component to the isocyanate molar equivalent contained in the polyisocyanate component is at least 1.1:1, at least 1.15:1 or at least 1.2:

1.

26. The herbicidal aqueous concentrate composition according to claim 23 or 24, wherein the ratio of the amine molar equivalent contained in the polyamine component to the isocyanate molar equivalent contained in the polyisocyanate component is from 1.1:1 to 1.7:1, from 1.1:1 to 1.6:1, from 1.1:1 to 1.5:1, from 1.1:1 to 1.4:1, from 1.1:1 to 1.3:1, from 1.15:1 to 1.7:1, from 1.15:1 to 1.6:1, from 1.15:1 to 1.5:1, from 1.15:1 to 1.4:1, from 1.15:1 to 1.3:1, from 1.2:1 to 1.7:1, from 1.2:1 to 1.6:1, from 1.2:1 to 1.5:1, from 1.2:1 to 1.4:1 or from 1.2:1 to 1.3:

1.

27. The herbicidal aqueous concentrate composition according to claim 26, wherein the weight ratio of the acetanilide herbicide to the shell wall is from 13:1 to 6:1 or from 10:1 to 6:

1.

28. The herbicidal aqueous concentrate composition according to claim 1 or 11, wherein the microcapsules have an average particle size of at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9 or at least 10 μm.

29. The herbicidal aqueous concentrate composition according to claim 1 or 11, wherein the microcapsules have an average particle size range of 2 μm to 15 μm, 2 μm to 12 μm, 6 μm to 15 μm, 7 μm to 15 μm, 7 μm to 12 μm, 8 μm to 12 μm, 9 μm to 12 μm or 9 μm to 11 μm.

30. The herbicidal aqueous concentrate composition according to claim 11, wherein the concentration of the acetanilide herbicide in the aqueous phase is 0.5% to 5%, 0.5% to 2%, 0.75% to 10%, 0.75% to 5%, 0.75% to 2%, 1% to 10%, 1% to 5% or 1% to 2% by weight of the total acetanilide herbicide.

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