MXPA97003575A - Formulations of clomazone de baja volatili - Google Patents

Abstract

A herbicidal composition is prepared, containing 0.120 to 0.480 kilograms of Clomazone per liter of formulation, and has a Clomazone volatility of less than fifty percent that of an emulsifiable concentrate containing 0.480 kilograms of Clomazone per liter of formulation, interfacial reaction of the polymethylene polyphenyl isocyanate with a polyfunctional amine, selected from ethylenediamine, diethylenetriamine, triethylenetetramine, 1,6-hexanediamine, and mixtures thereof, in an aqueous phase, optionally containing 0.05 to 0.25 percent by weight of a viscosity modifier / xanthan gum stabilizer. Several such formulations and the method for their preparation are described

Description

LOW VOLATILITY CLOMAZONE FORMULATIONS The present invention relates to clomazone formulations that have a reduced volatility in relation to conventional emulsifiable clomazone concentrates. In particular, it relates to microencapsulated clomazone formulations in which the clomazone is encapsulated in a polyurea shell. Clomazone is the common name for 2- (2-chlorophenyl) methyl-4,4-dimethyl-3-isoxazolinone, a highly effective herbicide, but it is also highly volatile, so much of that clomazone applied to the soil in one area target, it can move to adjacent areas and there cause discoloration, more typically bleaching or some degree of discoloration, of a variety of crops, trees or decorative plants. While this discoloration is indicative of the mode of action of the herbicide, it may be temporary, when the plants are exposed to sufficiently low concentrations, and is poorly received, even if it does not result in the destruction of the plant. Therefore, the label for the use of the herbicide Command® 4 EC Herbicide, an emulsifiable concentrated formulation of commercial use, containing 0.480 kilograms of clomazone per liter of the formulation, lists a number of restrictions on how to use the product, which include environmental conditions, spray volume and pressure, and distance from the areas where the plants are in commercial production. For example, for preemergence applications, the clomazone will not be applied within 457 meters of commercial fruits, nuts or vegetable production or commercial greenhouses or nurseries. Clearly, this is a severe limitation on the use of a herbicide. It is the purpose of the present invention to reduce the volatility of clomazone formulations, so that the problem of damage away from the site is significantly reduced, i.e. by at least fifty percent, while maintaining a satisfactory level of herbicidal activity in the target area. Attempts to prepare encapsulated clomazone formulations by general methods known in the art, including polyamide and polyurea coatings, have frequently resulted in formulations that not only give little or no reduction in volatility, but also have poor characteristics physical, for example, unwanted agglomeration of the capsules or phase separation. Perhaps one factor that accounts for the difficulty in preparing satisfactory formulations is the significant water solubility of clomazone. No reports of encapsulated clomazone formulations have been found. It has now been found that encapsulated formulations of clomazone, for which volatility is reduced to fifty percent or less of that of the commercially available Emulsifiable Concentrate EC, of the clomazone, and which retain a satisfactory level of herbicidal activity. , they can be prepared, as a condition that the isocyanate and amine moieties, which are in the form of the urea cover wall, are carefully selected. The process of the invention involves the following steps: (a) supplying an aqueous phase containing an emulsifier, preferably a polyvinyl alcohol, partially hydrolyzed; an antifoaming agent and, optionally, a viscosity modifier of xanthan gum / stabilizer; (b) supplying an immiscible phase in water, consisting of clomazone and polymethylene-polyphenyl isocyanate, with or without a hydrocarbon solvent; (c) emulsifying the immiscible phase with water in the aqueous phase, to form a dispersion of immiscible droplets with water through the aqueous phase; (d) stirring the dispersion, while adding to it, in net form or in aqueous solution, ethylenediamine, diethyltriamine, triethylenetetramine, 1,6-hexanediamine or a mixture of polyfunctional amines, thereby forming a polyurea shell wall around the droplets immiscible with water. Once the microcapsules are formed, the suspension is cured by moderate heating, after which one or more stabilizing agents may be added, such as propylene glycol, xanthan gum, smectite clay or an ionic dispersing agent, such as a sulfonate of a naphthalene of alkyl, as is well known in the art. It has also been found that adjusting the pH of the formulation from moderately acidic to moderately alkaline conditions, such as in the range of 6.5 to 9.0, for example a pH of 8.9, results in a formulation having improved storage stability. The addition of these materials after encapsulating and curing to adjust the viscosity and suspension capacity have no effect on clomazone loss through volatility or the herbicidal efficacy of the formulation. The aqueous phase will ordinarily contain from 0.3 to 3.0, preferably from 0.8 to 2.0 percent by weight of one or more emulsifiers, for example polyvinyl alcohol, 0.05 to 0.20, preferably 0.06 to 0.15, percent by weight of the rubber viscosity modifier of xan-tano / stabilizer, if used, and 0.1 to 1.0, preferably 0.4 to 0.9 weight percent of the antifoam agent. The water immiscible phase will ordinarily consist of 60 to 85, preferably 65 to 77 weight percent of the clomazone, an amount of polymethylene-polyphenyl isocyanate (PMPPI) so that the ratio of the clomazone to the PMPPI is found in the range from 1: 1 to 6: 1, preferably from 4.5 to 4.8: 1, and an aromatic hydrocarbon solvent for the two solutes. However, the use of the solvent is optional in the preparation of formulations containing more than 0.24 clomazone per liter of formulation. In such preparations, a small amount of the solvent can still be used to lower the melting point. The amine solution will ordinarily contain from 10 to 100, preferably from 30 to 40 weight percent of ethylenediamine, diethylenetriamine, triethylenetetramine, 1,6-hexanediamine, or preferably a mixture of polyfunctional amines, with ethylene diamine being used only in a mixture. The emulsification step requires a high cut mixture to give small droplets of the immiscible phase. Factors that influence the size of the droplets, which determine the final size of the microcapsules, as well as the stability of the emulsion, include the speed and period of mixing, the type and amount of the surfactant, the temperature of the solvent and viscosity, like xanthan gum, when used. The selection of the appropriate size of microcapsules to achieve the purposes of the invention requires a balance between the competing factors. In general, increasing the size of the microcapsules decreases the volatility, but also the suspension capacity of the particles decreases, while the size decreases, better suspension capacity is provided, but greater volatility. For the purposes of the present invention, the average size of the microcapsules is from 5 to 50 microns, preferably from 5 to 30 microns. The operating conditions for supplying microcapsules of the desired size will depend on the emulsifying equipment used and the adjustment to determine the appropriate conditions is within the scope of a person skilled in the art. In contrast to the conditions of the emulsification step, the stirring during the addition of the amine should be moderate. Stirring is continued while the suspension is cured by heating at a temperature of 35 to 60, preferably 45 to 502C, for 3 to 10, preferably 4 to 5 hours. Amounts of additives subsequent to encapsulation, which are typically added, will be selected from one or more of 0.75 to 6.5% by weight of propylene glycol, 0.05 to 0.30% by weight of xanthan gum, 0.25 to 0.50% by weight of smectite clay and 0.05 to 6.0% by weight of one or more surfactants. each percent by weight is relative to the weight of the formulation, after the addition of the stabilizers. The formulations of the present invention are prepared by the methods exemplified in the following examples.

EXAMPLE 1 Preparation of a Capsule Suspension Formulation (1.5 CS) of 0.18 ks / liter A loading solution of polyvinyl alcohol partially hydrolyzed at 20% (w / w) aqueous, having an average molecular weight of 13,000 to 23,000 (Airvol ® 203) was prepared by heating and heating appropriate amounts of polyvinyl alcohol and water at about 80-900C for one hour. The cooled solution was stored for later use. In a 1 liter stainless steel bucket, 20.0 grams of the 20% aqueous polyvinyl alcohol solution prepared above were placed, 1.8 grams of a 100% polydimethyl siloxane antifoam agent (Dow Corning® 1500), 15.0 grams of aqueous 2% xanthan gum (Kelzan® M) and 400.0 grams of water. After mixing for 20 seconds at high speed in a high-cut mixer, a pre-mix solution of 140.0 grams of clomazone, 30.0 grams of polymethylene-polyphenyl isocyanate (PMPPI, Mondur® MR) and 30.0 grams of petroleum solvent ( a mixture of aromatic hydrocarbons Cg to C? 5, depleted of naphthalene, evaporation point of 95SC, Aromatic 200 ND), were added and the mixture was emulsified in the high-cut mixer for five minutes. The mixture was then placed in a one liter jacketed resin flask with this jacket preheated to 50SC. the mixture was stirred at a moderate speed with an air-powered stirrer, and a solution of 19.0 grams of triethylenetetramine (TETA) in 35.0 grams of water was added in one portion. The mixture was then stirred at 50 ° C for four hours. After this time, 2.5 grams of smectite clay containing magnesium aluminum silicate, titanium dioxide and cristobalite (Veegum® Ultra) and 15.0 grams of aqueous 2% xanthan gum (Kelzan®M) were added to stabilize the formulation. This formulation was then stirred for about one hour and stored for further use. The formulations described in Tables 1 and 2 were prepared in this manner.

EXAMPLE 2 Large Scale Preparation of a Suspension (2.0 CS) of 0.24 K Capsules / Clomazone Liter (ED Formulation A 2.38 kg solution of polyvinyl alcohol (Airvol 203), 1.08 kg of an aqueous solution of a polydimethyl antifoaming agent -20% siloxane (Dow Corning® 1520) and 0.095 kg xanthan gum, modifier / stabilizer (Kelzan®S) in 128.91 kg of water, were placed in a 1892 liter stainless steel vessel, and stirred at 80sc After one hour, after this time, the solution was cooled to 20 ° C and placed in an intermittent homogenizer of 302.8 liters.With the homogenizer in operation, a previously mixed solution of 73.18 kg of technical clomazone, 15.76 kg of isocyanate of polymethylene polyphenyl (PMPPPI, Modur® MR) and 15.76 kg of petroleum solvent (a mixture of Cg to C15 aromatic hydrocarbons, 95oc evaporation point, Aromatic 200) was fed by gravity into the homogenizer for a period of 15 to 90 seconds The rocking was homogenized for two to three minutes. Upon completion of homogenization, the mixture was placed in a jacketed reactor, with this jacket pre-heated to 50 seconds. To the jacketed reactor, a mixture of amines consisting of 4,976 kg of triethylene tetramine (TETA) and 4,976 kg of the 1,6-hexanediamine (HDA) was added over a period of 30 seconds. After the addition of amines was complete, the mixture was cured, with stirring, at 25SC-502C for a period of four hours. At the end of the curing period, 16.19 kg of propylene glycol and 0.540 kg of xanthan gum were added to stabilize the formulation. This formulation was then cooled below 30 ° C and stored for later use. It had a viscosity of 1870 cps and a suspension capacity of 82%. Both formulations are described in Tables 3 and 4 and prepared as in Example 2. Formulation A-1 is a large-scale version of Formulation A and Formulation E-1 is a large-scale version of Formulation E.

Formulation P, a 0.360 kg / liter formulation, the components of which are given in Tables 3 and 4, was prepared by the method of Example 2. In this preparation 0.060 kg of the sodium sulfonated naphthalene condensate was added to the aqueous phase , during its preparation. The additives after encapsulation, which include the remainder of the sodium sulfonated naphthalene condensate, were added after a curing period at about 35 ° C, while the formulation continued to be mixed and cooled to room temperature. The presently preferred practice, after the curing step, is to continue stirring the formulation until the temperature reaches about 35SC and then add the hydrochloric acid to arrive at a pH of about 7.8. The additives after encapsulating, which include the rest of the naphthalene sulfonated sodium condensate, were added, and the stirring was continued for about 30 minutes to give a homogeneous mixture. In subsequent preparations of Formulation E by the method of Example 1, certain refinements in the process have been found to be advantageous. Adjusting the pH of the aqueous solution to 4, reduced the inconvenient reaction between the PMPPI and water, as well as cooling the solution to 8-108C. The preparations were carried out with the clomazone solution and the amine solution, as well as the initial aqueous solution, all cooled to 8-lOsc. However, when there is no solvent in the immiscible phase in water, low temperatures are not used to avoid clomazone freezing. Other formulations prepared by the method of Example 1, but differing from the formulations of the invention in the components of any phase containing isocyanate or amine, proved not to be satisfactory in controlling the volatility of the clomazone or in the physical stability of the formulation. The compositions of the representative unsatisfactory formulations are given in Table 5. Three of these formulations failed to adequately control the volatability of the clomazone, as shown below. Formulation O was too viscous (6360 cps). Formulation L is the same as Formulation A of the present invention, except that the polymethylene polyphenyl isocyanate (PMPPI) was replaced with toluene diisocyanate (TDI). TDI is more reactive in water than PMPPI, which causes unwanted side reactions that lead to foam formation in the emulsification stage of the preparation of this formulation. Formulation M was an attempt to copy the formulation successfully used in a capsule suspension formulation of 0.480 kg / liter of an insecticide, replacing the insecticide with clomazone. The microcapsules produced were too small and thus the TDI caused too much foam formation problems. Formulation N is the same as Formulation A of the present invention, except that the viscosity / stabilizer modifier of the xanthan gum was not used in the emulsification step. Lots of Formulation N were prepared in this manner and supplied microcapsules that were not only somewhat small, but were not uniform in size and tended to aggregate. Also, the formulation had a poor physical stability that resulted in the separation of ase. Obtaining the desired combination of reduced volatility, physical properties and efficacy was not achieved simply by following the prior art, as shown by two additional preparations. Formulations V and W were prepared by the method of the U.S. Patent No. 4,280,833, Example 8. The composition of these formulations is given in Table 5a. Both formulations separated when resting, forming a hard layer at the bottom of the container, which could be redispersed by shaking. Each gave at least as much of the clomazone release as the standard Co mand® 4 EC herbicide, when subjected to the laboratory volatility test described below. The average size of the microcapsules of the formulations of the invention, as well as the unsatisfactory formulations, are given in Table 6.

Volatility Studies Laboratory tests for the volatility of the capsule suspension (CS) formulations were carried out in the following manner. Sufficient top soil, unsterile, to conduct the test, was passed twice through a 14 mesh screen, to remove large particles and debris. The fine particles were then removed through a 30 mesh screen, leaving behind the earth with particles of intermediate size. This earth with particles of intermediate size, 240 grams, spread uniformly to a thickness of one to two millimeters over an area of approximately 27.9 cm. x 41.3 cm in a tray that measures 32.4 cm. x 45.7 x 1.9 cm. The soil was then sprayed from an upper runner sprinkler, calibrated to deliver 187 liters of water per hectare. The sprayed mixture consisted of enough clomazone test formulation to deliver 0.0712 grams of active ingredient in 20 ml of water. In this way, the clomazone test formulation was applied to the soil at a rate of 1.0 kg i.a. (active ingredient) / ha. Immediately after the treatment, the earth was enclosed in a glass jar, where it remained briefly until used. For each clomazone test formulation, four 22 mm x 300 mm glass chromatography columns, each containing a thick sintered glass barrier in the bottom, were contacted through their bottom ends in the air collector of Multiple doors, which deliver an air pressure equal to a number of columns simultaneously. In each of the four columns, 59 g of the top treated soil were placed, which filled about 200 mm of the length of the column. At the top of each column, a polyurethane foam stopper was then placed to fit inside the 21 to 26 mm diameter tube. As soon as after the treatment, as the columns could be adjusted, a slow stream of air (0.75-1.00 liter per minute per column) of the multi-door air manifold was passed through the ground in each column, causing the Volatilized clomazone was collected in the polyurethane foam stopper. The time between the treatment of the soil and the beginning of the air flow was around one hour. The flow of the are continued for about 18 hours. Following the 18-hour collection period, the polyurethane foam plug of each column was placed in a 20 ml plastic syringe. The polyurethane foam stopper was completely removed by pushing 15 ml of methanol into the syringe and through the stopper, forcing the methanol extract into a beaker and repeating the process several times. An aliquot of 0.04 ml of the 15 ml sample was diluted with 0.96 ml of methanol and 1.0 ml of water. An aliquot of 0.1 ml of the solution was analyzed in the clomazone content using an enzyme-linked immunosorbent assay (ELISA), a method reported by RV Darger et al (J. Agr. And Food Chem., 1991, 39, 813-819). The total clomazone content of the foam plug, expressed in microgams, of each sample was recorded and compared to the clomazone content of the sample from the standard, the Command® 4 EC herbicide. The test results, given in Table 7, show that the CS formulations of the present invention are effective in reducing the amount of clomazone lost by volatility. While all the formulations listed give a significant reduction in volatility, the results of Formulations E and F, prepared from mixtures of TETA and HDA, are particularly notable, losing only 1 8 and 10% respectively, both clomazone and was lost from the standard. 4 EC. The formulations of 0.24 kg / 1 obtained from simple polyfunctional amines, Formulation B of TETA and Formulation D of HDA, each lost more than twice as much clomazone as the formulations prepared from the mixtures. Similarly, Formulations g and H each had less lost volubility than that of either HDA or DETA alone (Formulations D and K). Thus, in the preparation of the formulations of this invention, the use of DETA or TETA mixtures or both with HDA, particularly in ratios of: 1 to 1: 3, gave an unexpectedly greater reduction in volubility. The mixtures of TETA and EA gave a lower volatility than that of the TETA alone. However, it should be noted that Formulation P, a formulation of 0.36 kg / 1, with DETA alone, gave as much reduction in volatility as Formulations G and H. The unsatisfactory formulations, L, M and N, are clearly less efficient in reducing the volubility of clomazone. The loss of high volatility for Formulation L (91% of that loss by the standard clomazone 4.0 EC) suggests that the polymer walls formed of triethylene tetramine (TETA) and TDI are too permeable, allowing the clomazone to volatilize and the walls formed of PMPPI and TETA or PMPPI in combination with TETA and 1,6-hexanediamine (HDA), are much less permeable, so the clomazone loss of volatility is very reduced. Formulation M, which gives excellent results when the active ingredient is an insecticide less soluble in water, is totally unacceptable for the clomazone, giving a volubility equal to that of the clomazone standard 4.0 EC. The difference between Formulations A and N in reducing clomazone loss through volubility is particularly surprising, since the only difference is the absence of the xanthan gum in the aqueous solution prior to encapsulation in Formulation N. The function of xanthan gum does not seem predictable, however, since the only difference between Formulations K and O is the presence of xanthan gum in the aqueous solution, before encapsulation in K. These two formulations have the same loss of volatility, but the viscosity of Formulation K is 3640 cps, while of O is 63601. No appreciable difference was found between Kelzan®M and xanthan gum and Kelzan S in the aqueous phase, before encapsulation in its effect on the formulations. Formulations V and, based on the previous patent, were no better than the 4 EC formulation in controlling volatility. The tests to determine the volatility of the clomazone CS formulations in the field in relation to the standard herbicide Command® 4 EC, were carried out as follows. One trial in Formulation A-1 was conducted in a sunflower field of two weeks of age, a plant species susceptible to clomazone. The lots were established in a grid of 12 x 14 meters. Each batch was prepared by removing the sunflower seedlings and other vegetation from the areas of about 60 cm. in diameter, located at the intersections of the grid lines. The grid lines were separated by 12 meters in one direction and 14 meters in the perpendicular direction. The edge of a replica was at least 12 meters from the edge of the next, a distance sufficient to prevent interference between the replicas.

On each lot, where the soil was exposed, a barrel of open ends of 60 cm was placed. in diameter, which was lined with a plastic sleeve like in a garbage can liner. Each batch was sprayed with 10-15 ml of an aqueous dispersion containing 0.12 g of active ingredient. To minimize clomazone flow, the spray was conducted into the barrel using a hand sprayer. Upon completion of each application, the barrel was left in place, and the top was covered for a few minutes to allow the dew to settle on the surface of the earth. The barrel was then removed leaving each lot open to environmental conditions. Three to four replicates were made for each test formulation. To prevent cross-contamination, the plastic sleeve was replaced before applying each new test formulation. The test was evaluated seven days after the treatment, measuring the distance from the center of each lot to, first, the most distant point where the discoloration of the sunflowers could be found, then at intervals of 45c around the center of the lot. The discoloration area of the sunflowers was calculated and the direct treatment area was subtracted to supply the area affected by the clomazone's volubility. A second test of Formulation A-1 was carried out in a similar manner in a second field of sunflowers, this time with a 44 cm barrel. and a grid of 14 x 14 meters. The total areas affected by the clomazone movement from each test site for each test formulation and the standard clomazone 4.0 EC formulation were determined. From these data, a percentage reduction of the area bleached by the clomazone compared to the standard Command® 4 EC was calculated for each test formulation. A third test, this time with the PO Formulation, was a series of tests, carried out in different geographical locations that have different environments and soil conditions. At each location, a batch of 0.4647 hectares was planted with sunflowers. The clomazone formulations were applied to a 3 x 3 meter lot of land, when the sunflowers had reached the 2-6 leaf stage. The conditions previously required for the application were that the soil was humid, but not saturated, to facilitate volatilization. The evaluations were made 7 to 10 days after the application and 10-14 days after the first significant rain fall, by means of the same general method described in the first test. The given areas are total for all the sites; the reduction percentage is an average of all the sites. The test results, given in Table 8, show that Formulation A-l reduced the area affected by clomazone by half compared to Command 4 EC and Formulation P was significantly more effective in reducing volatility.

Efficacy Studies Seeds of farm grass (Echlnochloa crus-galli) giant setaria (Setaria faberi), yellow setaria (Setaria lutescens), sorghum (Sorghnm bicolor) and alcotán (Abutilón theophasti), were planted in a top soil It contains 25 cm fiber drawers. x 15 cm 7.5 cm Each species was planted as a single row in the drawer, which contains five rows. There were three replicas of plant boxes for each application regime of the test formulation. The charge dispersions of each test formulation were prepared by dispersing a sufficient amount of formulation to deliver 0.0356 g of the active ingredient in 40 ml of water. From the load dispersion, 20 ml were removed and serially diluted with 20 ml of water to supply application regimes of 0.25, 0.125, 0.0625, 0.0313, 0.0156 and 0.0078 k of i.a. /he has. The dispersions of the test formulation of each application regime were then sprayed onto the soil surface by a track boulder on a spray cover. The drawers were also sprayed as before with the same regimens of the standard Command® 4 EC herbicide. Untreated controls were also included in each test. When the spray is complete, the drawers were placed in a greenhouse, where they were kept for fourteen days. After this time, the test was visually evaluated on the percentage of weed control. The weed percentage control data for each test formulation and the Command 4 EC herbicide were subjected to regression analysis to determine the application rate that would provide 85% weed control (SDB) for each species of weeds. From these data, the relative potencies of the test formulations (the relative potency of the Command 4 EC herbicide is 1.0) were determined by means of the following relationship: DEß5 of Formulation Relative Potential of Formulation = DEßd of Herbicide Command The test results shown in Table 9 showed a relatively poor performance for Formulation E in the greenhouse. As shown below, the performance of Formulation E in the field was excellent. The reason for this difference between the performance in the greenhouse and the field is not understood. However, the greenhouse performance of Formulation P was excellent, as was the performance in the field, as shown below. In the efficacy field test of Formulation A-1, the test formulations were sprayed onto the soil surface (preemergence) at an application rate of 1.12 kg i.a. per hectare in lots of 3.87 x 9.14 meters, planted with cotton weed seeds. There were four replicates of the batches for each formulation tested. The test formulation was applied by means of a filler sprayer, equipped with spray nozzles and fan, at a volume of 140 to 187 liters / ha and a spray pressure of 1.96 to 2.1 kg / cm2. The lots were evaluated for the percentage of weed control 15 and 30 days after the emergence of the plant species in the test. The cotton plants were evaluated in the discoloration, development and reduction of the erect state. The test results, given in Table 10, showed that this CS formulation was slightly less effective against three of the four test species and essentially equivalent to the 4 EC in the effects on the cotton. (The similarity in the effect on cotton was not expected, since the test is the result of direct application and does not involve movement to an adjacent site.) In the field test of Formulation E, the test formulations were sprayed on the soil surface (preemergence) at application rates of 0, 0.14, 0.28 and 0.56 kg of i. to. / ha in lots from 2,042 to 3,658 meters, planted with eight different plant species. There were four batches of replica for each formulation used. The test formulations were applied using a fill spray, equipped with four fan spray nozzles, at a delivery volume of 187 liters / ha at a spray pressure of 1.75 kg / cm2. The data in Table 11 show that this CS formulation at 0.56 kg of i. to. per hectare gives commercial control, defined as at least 80 to 85 percent control for all species, where the standard is given by commercial control, except for the bicolor sorghum of 0.56 kg / ha, which falls slightly below of the target percentage for control. Table 12 provides the results of a field test of Formulation P and the 4EC formulation in which both formulations were applied at 0.985 kg / ha, preemergence. It is apparent that in most cases where the 4 EC formulation gives commercial control, Formulation P does as well. Again, the effect of Formulation P encapsulated on cotton is negligible. Table 13 provides another field test of Formulation P, against the applied preemergence, which shows that 0.56 kg / ha of the encapsulated formulation controls all species, except bicolor sorghum.

As noted above, the stabilizers added after encapsulating and curing, is thought to have no effect on the volatility or efficiency of the formulation. They are added to stabilize the formulation and adjust the viscosity. It is preferred that each formulation of this invention have a suspension capacity of more than 70%, a viscosity of 1700 to 3800 cps, and a wet screen screening of 100 mesh of more than 99.95%. It will be understood that there are variations of the specific embodiments described herein, without departing from the spirit or concept of the present invention, as defined in the claims. Mixtures in such variations are included in which the encapsulated clomazone of this invention is part of a mixture with one or more other herbicides, for example flumeturon or sulfentrazone, when they are or are not encapsulated.

Table 1 Preparation of Suspension Formulations of Clomazone Capsules (Components? Quantities) Weight (grams) Formulation (ka / ll A (0.18) B (0.24) C (0.18) D (0.24) E (0.24) F (0.24) Component Aqueous Solution Water 430.70 493.00 430.70 493.00 493.00 493.00 PVA 4.0 4.58 4.00 4.58 4.58 4.58 Xanthan gum (i.a.) 0.3 0.35 0.30 0.35 0.35 0.35 Antifoam (i.a.) 1.8 2.06 1.80 2.06 2.00 2.06 Clomazone Isocyanate Solution 140.0 280.00 140.00 280.00 280.00 280.00 Oil Solvent 30.0 60.00 30.00 60.00 60.00 60.00 PMPPI 30.0 60.00 30.00 60.00 60.00 60.00 Amina Solution TETA 19.0 38.00 - - 19.00 9.50 HDA _., 19.00 30.00 19.00 28.50 Water 35.0 62.00 31.00 70.00 62.00 62.00 Post Encapsulated Stabilizers Clay of Smectite in 2.5 Water 14.7 - - - - - Propylene glycol - 19.60 9.00 18.00 9.00 18.00 Xanthan Gum (.a.) 0.3 0.40 1.00 2.00 1.00 2.00 Table 1 (Continued) Preparation of Suspension Formulations of Capsules Clomazone (Components and Quantities) Weight (grams) Formulation (ka / H G (0.24) H (0.24) 1 (0.24) J (0.24) K (024) Component, Aqueous Solution Water 493.00 493.00 493.00 493.00 493.00 PVA 4.6 4.6 4.58 4.58 4.58 Xanthan gum (i.a.) 0.4 0.4 0.35 - 0.35 Antifoam (i.a.) 2.1 2.06 2.06 2.06 2.06 Clomazone Isocyanate Solution 280.0 280.00 280.00 280.00 280.00 Oil Solvent 60.0 60.00 60.00 60.00 60.00 PMPPI 60.0 60.00 60.00 60.00 60.00 Amin solution EDA - - 7.6 7.6 TETA - - 30.4 30.4 DETA 1 111..2200 1 199..0000 - - 38.00 HDA 19.00 19.00. . Water 69.8 62.00 62.00 62.00 62.00 Post Encapsulated Smectite Clay Stabilizers in Water. . . . .

Propylene glycol - 41.00 19.60 19.60 19.60 Rubber Xantano (i.a.) - 1.00 0.40 0.40 0.40 • PVA - Airvol® 203, polyvinyl alcohol. • Xanthan gum - Kelzan®M and Kelzan S, xanthan gums that differ in that S has been superficially treated to improve the ease of dispersion. it was used in all cases, except post encapsulated in Formulations A, C, D, F and H. • Antifoam - Dow Corning® 1500 is a 100% polydimethylsiloxane. Dow Corning 1500 is a 20% solution; the amount shis the active ingredient (i.a.). 1500 was used in Formulations A and C; 1520 in the others. • Solvent oil - Aromatic 200, a mixture of aromatic hydrocarbons Cg-C ^ 5. Evaporation point: 95 °. The one used in Formulation A was free of naphthalene. • PMPPI -Mondur® MR, polymethylene polyphenyl isocyanate. • TETA - triethylenetetramine • HDA - 1,6-hexanediamine • Smectite clay - Veegum® Ultra, clay consisting of magnesium and aluminum silicates with titanium dioxide and cristobalite present. • EDA - ethylenediamine. • DETA - diethylenetriamine.

Table 2 Capsule Suspension Formulations (Clomazone SO (Components and Percentages Weight / Weight) Percentage (weight / weight) Formulation (ka l) A (1.8) B (0.24) C (0.18) D (0.24) E (0.24) F (0.24) Component Clomazone 19.77 27.45 20.09 27.45 27.72 27.45 Polymer Encapsulator PMPPI 4.24 5.88 4.31 5.88 5.94 5.88 HDA - - 2.72 2.94 1.88 2.79 TETA 2.68 3.73 - - 1.88 0.93 Polyvinyl alcohol 0.56 0.45 0.57 0.46 0.45 0.45 Solvent oil 4.24 5.88 4.31 5.88 5.94 5.88 Anti-foaming agent 0.25 0.20 0.26 0.20 0.20 0.20 polydimethylsiloxane Xanthan gum -Modifier 0.08 0.07 0.19 0.23 0.13 0.23 viscosity / Stabilizer stabilizer - polyethylene glycol 1.92 1.29 1.77 0.89 1.77 Esmectlta clay - "_, modifier. or. or -the viscosity Water 67.83 54.42 66.26 55.20 54.95 54.42 TOTAL 100.00 100.00 100.00 100.00 100.00 100.00 Table 2 (Continued) Capsule Suspension Formulations (Clomazone SO) (Components? Percentages Weight / Weight) Percentage (weight / weight) Formulation (ko / h G (0.24) H (0.24) 1 (0.24) JÍ0.24) K0.24 Component Clomazone 28.00 26.7 27.45 27.45 27.45 Polymer Encapsulator PMPPI 6.00 5.70 5.88 5.88 5.88 EDA - - 0.75 0.75 TETA - - 2.98 2.98 DETA 1.12 1.80 - - 3.73 HDA 1.90 1.80 - - - Polyvinyl alcohol 0.46 0.44 0.45 0.45 0.45 Solvent oil 6.00 5.70 5.88 5.88 5.88 Anti-foaming agent 0.21 0.20 0.20 0.20 0.20 polydimethyl-siloxane Xanthan gum -Modifier 0.04 0.13 0.07 0.04 0.07 viscosity / Stabilizer stabilizer - polyethylene glycol 4.67 1.92 1.92 1.92 Water 56.27 52.86 54.42 54.45 54.42 TOTAL 100.00 100.00 100.00 100.00 100.00 Table 3 Large-Scale Preparation of Clomazone CS Formulations (Components and Quantities Weight (kq) Formulation ika / l) A-1 (0.18) E-1 (0.24) P (0.36) Component Aqueous Solution Water 101.08 128.91 124.47 PVA 0.907 2.377 2.291 Xantano rubber 0.136 0.095 0.100 Antifoam 0.408 1.080 1.9504.30 Clomazone Isocyanate Solution 31.752 73.18 131.452 Oil Solvent 6.804 15.76 14.15 PMPPI 6.804 15.76 28.35 Amina Solution TETA 4.31 4.976 HDA. 4,976 DETA - - 18.14 Water 7,938 18,371 Post-Encapsulated Propylene Glycol Additives - 16,193 18.05 Xanthan gum - 0.540 11.88 Smectite clay 0.567 - - Bactericidal A1 .004 - - Bactericidal B2 0.080. _ Bactericide C3 - - 0.181 Naphthalene sulfonate of Na4 - - 2,405.3 Concentrated aqueous HCl - - 10.13 Amphoteric surfactant agent5 - - 11.79 1 Dowcida® A, (o-phenylphenate tetrahydrate) 2 Legend® MK (2-methyl-4-isothiazolin-3-ones) 3 Proxel® (1,2-benzisiazolin-3-one) 4 Sodium salt of 5M ™ rataine ™ sulfonated naphthalene condensate H2C-HA / sodium lauriminodipropionate * * as a 1.9% by weight dispersion Table 4 Large-scale Clomazone CS formulations (Components and Weight / Weight Percentages) Formulation A-1 E-1 Component Clomazone 19.74 25.93 35.02 Polymer encapsulated PMPPI 4.23 5.59 7.55 HDA - 1.76 - TETA 2.68 1.76 - DETA - - 4.83 Polyvinyl Alcohol 0.56 0.84 0.61 Oil Solvent 4.23 5.59 3.77 Polydimethylsiloxane - Antifoaming agent 0.25 0.38 0.53 Xanthan gum - 0.09 modifier 0.23 0.09 viscosity / stabilizer Polypropylene glycol - Stabilizer - 5.74 4.81 Smectite clay -Modifier of the Q 37 Viscosity Bactericides 0.05 - 0.05 Condensate of naphthalene sulfonate of Na - - 0.65 HCL concentrated aqueous - - 2.70 Amphoteric surfactant - - 0.94 Water 67.80 52.18 38.45 Total 100.00 100.00 100.00 Table 5 Unsatisfactory Clomazone CS Formulations (Components and Weight / Weight Percentages) Formulation L M Component Clomazone 20.38 30.43 20.38 27.45 Polymer encapsulated PMPPI - - 4.37 5.88 TDI 4.37 1.73 - - TETA 2.77 - 2.77 - DETA - 0.73 - 3.73 EDA - 0.15 - ~ Polyvinyl Alcohol 0.56 2.72 0.58 0.45 Oil Solvent 4.37 - 4.37 5.88 Polydimethylsiloxane - Agent 0.26 0.28 0.26 0.20 Antifoam Xanthan gum - 0.04 0.04 viscosity modifier / stabilizer Polypropylene glycol - Stabilizer - - - 1.92 Water 67.23 * 63.96 67.27 * 54.45 * Total 100.00 100.00 100.00 100.00 * Ten ml of a 10% solution of xanthan gum in propylene glycol were added to stabilize the formulation after it was prepared.

Table 5a Clomazone CS Formulations Unsatisfactory (Components and Percentages in Weight / Weight) Weight (g) Percentage (weight / weight) Formulation V w V w Component Clomazone 3CC.0 300.0 34.9 49.0 Polymer Encapsulator PMPPI 22.5 22.5 2.6 3.7 HDA (40%) 24.8 24.8 3.7 40.

Reax 88B® 11.6 5.7 1.3 0.9 Ethylene glycol - 25.7 25.7 3.0 4.2 Stabilizer Water 476.0 234.0 55.3 38.2 Total 860.6 612.7 100.00 100.00 Table 6 Average Microcapular Particle Size in Clomazone CS Formulations Formulation Size Formulation Mean Average Particle Size Particles (μm) (μm) A 26 J 11 B 21 K 17 C 16 L 14 D 18 M 2 E 15 N 9 F 15 0 7 G 23 P 14 H 12 V 21 I 12 17 The particle size was determined using a Malvem Master Sizer MS 20 device Table 7 Volatility of the CS Formulations Clomazone Compared to the Volatility of the Clomazone of the standard herbicide. Command® 4 EC Formulation Micrograms of Percent of 4.0 EC Clomazone collected A 28 32 B 30 33 C 17 19 D 20 22 E 8 8 F 9 10 G 15 14 H 13 14 1 21 15 J 23 17 K 14 17 L 81 91 M * 110 N 56 62 O 22 16 P 14 14 V 110 103 w 126 114 4.0 EC Standard 90-93 100 * Volatility determined by a different test method.

Table 8 Effect of Volatility of Clomazone CS Formulations Compared with the herbicide * »r? < - »mmnt > r-? B)? EC in Sunflowers in Field Studies Formulation (Sunflower Percent Test Area Number) Discolored (cm2) Reduction in the Area Fading by Volatility Al (l) 6578 49.0 Command 4 EC 12904 Al (2) 17449 52.8 Command 4 EC 37004 P 256334 67.5 Command 4 EC Table 9 Relative Potency of Clomazone CS Formulations Compared with the herbicide Command® 4 EC against Species d Weeds in Greenhouse Studies Relative Potency Formulation Setaria Grass Setaria Sorghum Setaria Hay Giant Farm Yellow Bicolor Green White A 0.70 0.54 0.35 0.66 ~ 0.69 D 0.50 0.59 1.02 0.40 ~ 0.36 E 0.19 0.28 * * - 0.34 P 0.63 0.54 .. 0.95 0.95 0.90 * Too small to measure the tested regime.

Table 10 Effectiveness of Formulation A-1 Clomazone CS Compared to Herbicj »fr > mt? mt? ri (8 A EC against Weeds in Field Studies% control of 15 DAE1 and 30 DAE Dimples Formulation Grass Pasture of Wonder Casia Johnson Bermuda 15 30 15 30 15 30 15 30 A-l 68 54 0 1 72 54 26 4.0 EC 85 56 20 55 66 70 21 Effects on Cotton Percent of Reduction Atrophy Discoloration of Erect State _15_ 30 A-l 0.7 0.5 none none 4. 0 EC 0.7 0.7 none no DAE is days after emergence of the test plant species; application rate of 1.12 kilograms of i.a./hectare.

Table 11 Effectiveness of Formulation E of Clomazone CS Compared to the Herbicide co "" «* '» ^ ® 4 EC »Against Certain Weed Species in Field Studies Percentage of Control Plant Species Application Regime (kg ¡a / ha) 1 0..56 0.28 0.14 Formulation E 4 EC E 4 EC E 4EC Farm Pasture 100 100 98 99 91 97 Setaria Gigante 100 100 98 98 95 96 Setaria Amarilla 95 93 50 57 50 35 Setaria Green 99 100 83 95 53 68 Bicolor sorghum 73 90 33 53 33 35 Pasto Johnson 100 100 93 97 85 93 Spring wheat 55 60 18 26 8 9 Hay White 100 100 93 96 85 93 Average of Pastos2 95 97 77 83 68 71 1 Formulations applied to batches with plants in pre-emergence White hay and spring wheat were not included in the pasture average. The percentage of control regimens was determined 20 days after treatment Table 12 Effectiveness of Formulation I P of Clomazone CS Compared to Herbicide Command® 4 EC Against Weeds in Field Studies 1 Control Percentage 15DAT 30 DAT 60 DAT Plant species Formulation P 4 EC P 4 EC P 4EC Hay white 95.0 95.0 97.5 97.55 - - Chumbera 89.3 90.5 83.6 90.7 77.3 88.5 Tártago Manchado - - 95.0 98.0 ~ - Hedgehog 58.8 72.5 56.8 59.4 87.5 93.5 Wideleaf marker 100.0 100.0 100.0 100.0 95.0 95.0 Johnson grass, plants - ~ 96.0 97.0 - - Garranchuelo grande - - 95.5 99.0 100.0 100.0 Wonder, dimpled 93.0 95.2 82.9 89.5 78.4 88.5 Wonder ivy leaf 92.1 95.0 88.0 91.0 57.0 77.0 Total wonder 73.9 70.9 73.9 71.6 66.9 73.0 Wonder Spp. _ - 95.7 99.3 99.0 99.0 Effects on Cotton (Percentage) 15DAT 30 DAT 60 DAT Formulation P 4 EC _P_ 4 EC _P 4EC Reduction of erect state 0 0 0 0 0 0 Atrophy 0.5 0.2 1.1 3.0 0 0 Discoloration 1.8 5.9 1.7 4.9 0 0.2 DAT is days after treatment. Application regime for both formulations: 0.9856 kg of i.a./hectare.

Table 13 Effect of Formulation P of Clomazone C8 Compared to Herbicide Command® 4 EC against Certain Bad Weeds in Field Studies Percentage of Control Application Regime (kg / ha) 1 Plant Species 0.25 0.50 bT 1.00 Formulation _P_ 4 EC _E 4 EC P 4 EC _P_ ± EC Amaranth, red root 73.8 88.8 92.3 97.5 100.0 100.0 100.0 100.0 Hay white 85.0 88.8 91.0 98.3 97.0 99.8 98.8 100.0 Common farm pasture 92.3 95.0 97.3 100.0 100.0 100.0 99.8 100.0 Two-color sorghum 65.0 73.8 76.3 96.0 91.3 97.3 94.5 100.0 1 Formulations applied to pre-emergence batches The control percentage classifications were determined 18 days after treatment.

Claims (14)

1. CLAIMS 1. A process for the preparation of effective herbicidal formulations of Clomazone, which have a volatility of less than fifty percent of the volatility of an emulsifiable concentrate of Clomazone, which contains 0.479 kilograms of Clomazone per liter of formulation, characterized by microencapsulation Clomazone by interfacial polymerization, by the steps of: a) supplying an aqueous phase, containing 0.3 to 3.0% by weight of one or more emulsifiers; optionally 0.02 to 0.20% by weight of a viscosity modifier / stabilizer of xanthan gum, and 0.1 to 1.0% by weight of an anti-foam agent; b) supplying an immiscible phase with water, consisting of Clomazone, polymethylene-polyphenyl isocyanate
2. (PMPPI) and a hydrocarbon solvent; the weight ratio of Clomazone to PMPPI being in the range of 1: 1 to 6: 1; c) emulsifying the phase immiscible with water in the aqueous phase, forming a dispersion of immiscible droplets with water through the aqueous phase; d) shaking the dispersion, while adding thereto a 100% by weight aqueous solution of at least one functional amine, selected from ethylenediamine (EDA), diethyltriamine (DETA), triethylenetetramine (TETA) and 1.6 -hexandiamine (HDA), with the condition that the EDA is used only in a mixture, the weight ratio of the polyfunctional amine to the PMPPI being in the range of 0.1: 1 to 1: 1, thus forming microcapsules having a wall of polyurea cover around the immiscible droplets with water; e) curing the microcapsules by continuing the agitation while the dispersion is encouraged at a temperature in the range of 35 to 60 seconds, for a period of 3 to 10 hours, to produce a formulation in which the average size of the microcapsules is in the range from 5 to 50 microns; f) optionally, adjust the pH between 6.5 and 9.0. 2. A process, according to claim 1, characterized in that the emulsifier is a polyvinyl alcohol; the Antifoaming agent is a polydimethylsiloxane; the ratio of Clomazone to PMPPI is from 4.5: 1 to 4.7: 1: polya ina is a mixture of TETA and HDA, in which the ratio of TETA to HDA is 3: 1 to 1: 3; the microcapsules are cured at 45-50 ° C, for 4-5 hours, and have an average size of 5 to 30 microns.
3. 3. A process, according to claim 2, characterized in that one or more stabilizers, selected from 0.05 to 0.30% by weight of xanthan gum, 0.75 to 6.5%, are added to the formulation after completing the curing step. by weight of propylene glycol, 0.5 to 6.0% by weight of one or more surfactants and from 0.25 to 0.50% by weight of smectite clay, to adjust the viscosity to 1700 to 3800 cps, and the suspension capacity to more than 70%, each percentage by weight is in relation to the weight of the formulation, after the addition of the stabilizers. 4. A process, according to claim 1, characterized in that the emulsifier is a polyvinyl alcohol; the Antifoam agent is a polydi ethyl siloxane; the ratio of Clomazone to PMPPI is from 4.5: 1 to
4. 4.7: 1; polyamine is a mixture of DETA and HDA, in which the ratio of DETA to HDA is from 3: 1 to 1: 3; the microcapsules are cured at 45-50 ° C for 4 to 5 hours and have an average size of 5 to 30 microns.
5. 5. A process, according to claim 3, characterized in that the amounts of the stabilizers added are 0.05 to 0.25 xanthan gum and 1.0 to 6.0 propylene glycol.
6. 6. A process according to claim 1, characterized in that the emulsifiers are a polyvinyl alcohol and, optionally, a sodium salt of the sulfonated naphthalene condensate; the Antifoaming agent is a polydimethylsiloxane; the ratio of Clomazone to PMPPI is from 4.5: 1 to 4.7: 1; the polyamine is the DETA, the microcapsules are cured at 45-500C for 4-5 hours and have an average size of 5 to 30 microns.
7. 7. A herbicidal formulation, prepared according to any of claims 1 to 6. 8. A process for the preparation of herbicidally effective formulations of clomazone, which have a volatility of less than fifty percent of the volatility of an emulsifiable Clomazone concentrate containing 0.480 kilograms of Clomazone per liter of formulation, characterized by microencapsulating Clomazone by interfacial polymerization, by the steps of: a) supplying an aqueous phase, containing
8. 0. 3 to 3.0% by weight of one or more emulsifiers; optionally from 0.02 to 0.20% by weight of a viscosity modifier / stabilizer of xanthan gum, and from 0.3 to 1.0% by weight of an anti-foam agent; b) supplying an immiscible phase with water, consisting of Clomazone, polymethylene polyphenyl isocyanate (PMPPI) and a hydrocarbon solvent; the weight ratio of Clomazone to PMPPI being in the range of 1: 1 to 6: 1; c) emulsifying the phase immiscible with water in the aqueous phase, forming a dispersion of immiscible droplets with water through the aqueous phase; d) stirring the dispersion, while adding thereto at least one polyfunctional amine, selected from diethyltriamine (DETA), triethylenetetramine (TETA), and 1,6-hexanediamine (HDA), the weight ratio of the polyfunctional amine to the PMPPI being in the range of 0.1: 1 to 1: 1, thus forming microcapsules having a polyurea shell wall, around the water-immiscible droplets; e) curing the microcapsules by continuing the agitation while the dispersion is encouraged at a temperature in the range of 35 to 60 ° C, for a period of 3 to 10 hours; f) optionally, adjust the pH between 6.5 and 9.0.
9. 9. A herbicidal composition, containing 0.120 to 0.480 kilograms of Clomazone per liter of formulation and having a volatility less than fifty percent of the volatility of an emulsifiable Clomazone concentrate, containing 0.480 kilograms of Clomazone per liter of the formulation , characterized by: a) an aqueous suspension of microcapsules, obtained from a polyurea shell surrounding a Clomazone core and a minor amount of a hydrocarbon solvent, the polyurea has been formed from the interfacial reaction of the polymethylene-polyphenyl isocyanate ( PMPPI) with ethylenediamine (EA), diethylenetriamine (DETA), triethylene tetra (TETA), or 1,6-hexanediamine (HDA), or a mixture of polyfunctional amines, provided that the EDA is used only in a mixture: b) from 0.2 to 1.00% by weight of polyvinyl alcohol; c) from 0.1 to 0.5% by weight of an Antifoam agent; d) optionally, from 0.07 to 0.30% by weight of xanthan gum, as a viscosity / stabilizer modifier; e) from 0.75 to 7.0% by weight of propylene glycol, the average size of the microcapsules being in the range of 5 to 50 microns and having a suspension capacity greater than 70%, a viscosity of 1700 to 3800 cps and a wet sieving analysis in a 100 mesh, greater than 99.95%.
10. 10. A composition according to claim 9, which contains 0.24 kilograms of Clomazone per liter of the formulation, characterized in that the weight ratio of Clomazone to PMPPI is from 4.5: 1 to 4.7: 1 and the polyfunctional amines are TETA and HDA , with a weight ratio of TETA to HDA from 3: 1 to 1: 3.
11. 11. A composition according to claim 9, which contains 0.24 kilograms of Clomazone per liter of formulation, characterized in that the weight ratio of Clomazone to PMPPI is from 4.5: 1 to 4.7: 1, and the polyfunctional amines are TETA and DETA , with a weight ratio of TETA to DETA from 3: 1 to 1: 3.
12. 12. A composition, according to claim 9, containing 0.24 kilograms of Clomazone per liter of formulation, characterized in that the weight ratio of Clomazone to PMPPI is from 4.5: 1 to 4.7: 1, and the polyfunctional amines are DETA and HDA, with a weight ratio of DETA to HDA from 3: 1 to 1: 3,
13. 13. A composition according to claim 9, which contains 0.36 kilograms of Clomazone per liter of formulation, characterized in that the weight ratio of Clomazone to PMPPI is from 4.5: 1 to 4.7: 1, and the polyfunctional amine is DETA.
14. 14. A composition according to claim 13, characterized in that the pH is adjusted between 6.5 and 9.0.