Plant protecting and regulating compositions – Plant growth regulating compositions – Plural active ingredients
Reexamination Certificate
2000-03-08
2001-04-17
Dees, Jose′ G. (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Plural active ingredients
C504S265000
Reexamination Certificate
active
06218339
ABSTRACT:
The present invention relates generally to the field of herbicidal chemical compositions. In particular, the present invention relates to novel compositions of a known herbicidal compound, namely clomazone, designed to reduce clomazone's characteristic volatility, thereby reducing risk of unintended herbicidal activity when clomazone is applied.
Clomazone (2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone) is a well-known herbicide commercially available for controlling many broadleaf and most grass weeds, and has been found to have selective characteristics making it particularly useful for the control of weeds when growing soybean, cotton, sugarcane, rice, tobacco, oilseed rape, vegetables and others. Clomazone can be phytotoxic to some non-targeted crops and naturally occurring plant species when applied to control undesired vegetation. Contact of clomazone with such unintended crops is the result of vapor transfer of the clomazone to sensitive species growing in adjacent areas.
Although clomazone can be, and is, sold with suitable label instructions to prevent exposure to sensitive crops, measures that will further decrease the exposure of the non-targeted crops to clomazone without substantial diminution of herbicidal efficacy against weeds will greatly expand the usefulness of clomazone and thus result in lower overall costs.
Other microencapsulated formulations of clomazone exist that are intended to control the volatile nature of the herbicide. See, e.g., U.S. Pat. Nos. 5,597,780, 5,583,090, and 5,783,520. Unfortunately, these formulations do not provide optimum herbicidal efficacy when compared to commercially available clomazone 4 pound/gallon emulsifiable concentrate (4.0EC) formulation. Given the commercial value of clomazone, improved formulations are therefore needed.
SUMMARY OF THE INVENTION
The present invention is directed to herbicidal formulations comprising microcapsules suspended in an aqueous liquid medium, wherein the microcapsules comprise a porous polymer wall, clomazone, and a fat, or resin. Different embodiments of the present invention include suitable concentrations of fat in the absence of resin, or resin in the absence of fat, or both fat and resin. Preferably, if included, the fat is at least 95% saturated. The present invention is also directed to said formulations wherein the porous polymer wall is, in part, the reaction product of the resin and a polyisocyanate. These formulations provide for the application of clomazone to undesirable vegetation encountered in the cultivation of various plant species, particularly agronomic crops, while minimizing off-target vapor transfer of the herbicide. Accordingly, embodiments of the present invention provide sufficient herbicidal efficacy with respect to unwanted vegetation, yet avoid the aforementioned problems seen in currently available formulations of clomazone.
In a first embodiment of the present invention there is provided an aqueous dispersion of microcapsules containing a herbicidally effective amount of clomazone in the presence of a highly saturated fat that is at least about 95% saturated.
In a second embodiment of the present invention there is provided formulations containing a herbicidally effective amount of clomazone wherein the microcapsule formed is, in part, the reaction product of a styrene-maleic anhydride copolymer resin and a polyfunctional polyisocyanate.
In a third embodiment of the present invention there is provided formulations containing a herbicidally effective amount of clomazone in the presence of a highly saturated fat that is at least about 95% saturated, and wherein the microcapsule formed is, in part, the reaction product of a styrene-maleic anhydride copolymer resin and a polyfunctional polyisocyanate.
Preferably, in those formulations containing it, the fat is at least about 98% saturated. Examples of such fats include, without limitation, waxes, suet, lard or tallow. The encapsulant is a porous condensate polymer of polyurea, polyamide or amide-urea copolymer. To provide acceptable volatility control without unacceptable sacrifice of herbicidal efficacy, the percentage of polymer comprising the microcapsules ranges from about 5 percent to about 35 percent by weight, preferably about 10 percent to about 25 percent by weight. Also the percentage of highly saturated fat of the encapsulated material ranges from about 0.5 percent to about 12 percent by weight of the organic phase, preferably about 1 percent to about 8 percent by weight, more preferably about 2 percent to about 6 percent by weight.
The microcapsules of the present invention provide volatility reduction of about 20-90 percent as compared with clomazone prepared and applied from an emulsifiable concentrate, which is commercially available. The microcapsules of the present invention also provide increased herbicidal efficacy against certain weed species from about one to about four times that of known clomazone microcapsule formulations that are also commercially available. Thus, the practice of the present invention, among other things, enables one to apply clomazone to the appropriate locus for control of weeds in crops while eliminating or substantially diminishing the risk of clomazone injury to plant species located in areas adjacent thereto without the need to resort to expensive and time-consuming preplant incorporation or special application procedures.
Definitions
The modifier “about” is used herein to indicate that certain preferred operating ranges, such as ranges for molar ratios for reactants, material amounts, and temperature, are not fixedly determined. The meaning will often be apparent to one of ordinary skill. For example, a recitation of a temperature range of about 120° C. to about 135° C. in reference to, for example, a range of temperature for a chemical reaction would be interpreted to include other like temperatures that can be expected to favor a useful reaction rate for the reaction, such as 105° C. or 150° C. Where guidance from the experience of those of ordinary skill is lacking, guidance from the context is lacking, and where a more specific rule is not recited below, the “about” range shall be not more than 10% of the absolute value of an end point or 10% of the range recited, whichever is less.
The term “ambient temperature” refers to a temperature in the range of about 20° C. to about 30° C. As used herein, the terms “crop”, or “crops”, “plant” or “plants” are one and the same, and refer to plants of interest or plant products derived thereof that are grown for ornamental, industrial or food uses. The terms “weed” or “vegetation” are one and the same, and refer to an unwanted plant or plants that are growing in a place or in a manner that is detrimental to a plant or plants of interest. The term “suet” refers to a hard fat found, for example, around the kidneys and loins of beef and mutton, or cattle, from which tallow is derived. The term “tallow” refers to a rendered fat from said cattle. The term “lard” refers to a soft, solid or semi-solid fat obtained by rendering fatty tissue of hogs. The term “CS” or “CS formulation” refers to a microcapsule or capsule suspension formulation of clomazone. The term, for example, “3.0 CS” or “3.0 CS formulation” refers to a microcapsule or capsule suspension formulation of clomazone containing 3.0 pounds of clomazone/gallon of finished formulation. The term “resin” refers to a chemical polymer with a molecular weight of about 100,000 to about 400,000. The term “cross-linking” refers to the chemical bonding between two adjacent polymer chains.
DETAILED DESCRIPTION OF THE INVENTION
The formulations of clomazone, in a first embodiment of the present invention, provide an aqueous suspension of microcapsules containing clomazone in combination with a highly saturated fat that is at least about 95% saturated.
In a second embodiment of the present invention there is provided formulations of clomazone wherein the microcapsule formed is, in part, the reaction product of a suitable resin and a polyfunctional polyisocyana
Becker John M.
Garcia Hylsa E.
Szamosi Janos
Dees Jose′ G.
FMC Corporation
FMC Corporation
Pryon Alton
LandOfFree
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