Plant protecting and regulating compositions – Plant growth regulating compositions – Plural active ingredients
Reexamination Certificate
2003-04-22
2004-11-30
Pryor, Alton (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Plural active ingredients
C504S116100, C504S128000, C504S130000, C504S135000, C504S142000, C504S144000, C504S145000, C504S146000, C504S147000
Reexamination Certificate
active
06825151
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to concentrated, liquid herbicidal compositions and the use thereof in a granular herbicide. More particularly, the present invention relates to a liquid herbicidal composition comprising (a) a first herbicide having an acid functionality in the form of a low volatile ester, (b) a solid second herbicide comprising (i) fluroxypyr in the form of a free acid and/or as a solid ester and, optionally, (ii) an herbicide having an acid functionality in the form of a free acid, and (c) an aprotic solvent. The herbicidal composition is applied to a solid substrate to provide a granular herbicide. The substrate comprises an inert material, like a clay, a fertilizer material, or a mixture thereof.
BACKGROUND OF THE INVENTION
Granular herbicides are important commercial products because of their ability to eliminate undesirable vegetation and their ease of application, either by hand or mechanical means. The granular herbicide can be an herbicide applied to an inert material, like clay or ground corn cobs, or can be a combination fertilizer/herbicide, wherein the herbicide is applied to a fertilizer material, i.e., a “weed and feed” composition.
In a granular form, an herbicide is impregnated into or absorbed onto an inert material or a fertilizer material. In the granular form, the herbicide product is supplied in a plastic bag, a plastic drum, or a fiber keg. The granular herbicide product is applied to vegetation by directly spreading the herbicide impregnated granules onto the vegetation at a suitable dosage rate.
It is known that certain compounds, like substituted benzoic acid herbicides and phenoxy-substituted carboxylic acid herbicides, possess selective herbicidal activity against broadleaf vegetation at dosages as low as a few ounces of active herbicide per acre. Accordingly, such herbicides are especially useful in eliminating unwanted vegetation from ornamental turf.
Solid substituted benzoic acid and the phenoxy-substituted carboxylic acid herbicides, and other solid herbicides having a carboxylic acid functionality in a free acid form or an ester form have been applied to susceptible vegetation, but herbicidal effectiveness is relatively poor because the water-insoluble form of these solid herbicides does not sufficiently penetrate the leaves of susceptible vegetation for fast and efficient eradication. In addition, application of such herbicides to a solid substrate is difficult because the free acid form and certain ester forms are solids. Therefore, the solid free acid and ester forms of these herbicides either must be applied to a solid substrate from a solution, which requires solvent removal or absorption of the solvent onto an adsorbent and/or drying agent to provide a dry granular herbicide. Alternatively, to avoid solvents, the solid forms of the herbicide must be applied as either a very finely ground powder or a melt, which requires an expensive heating step and more complex grinding, heating, and application apparatus and processes.
To improve performance, the substituted benzoic acid herbicides and the phenoxy-substituted carboxylic acid herbicides, and other solid herbicidal compounds having an acid functionality, traditionally are converted from the free acid form to a liquid ester form or to a salt form. The salt and liquid ester forms have enhanced water solubility and leaf penetration properties. Both the liquid ester form and the salt form of these herbicidal compounds are available commercially, and are provided as liquid products containing a known, but variable, amount of the active herbicide. For concentrated products, a predetermined amount of water is added to dilute the active herbicide before spraying susceptible vegetation. The predetermined amount of water is related to the concentration of the active herbicide in the liquid herbicidal product and the desired strength of the spraying solution.
In general, the ester forms of these herbicides are provided as petroleum distillate-based emulsifiable concentrates that are diluted with water. The resulting herbicide emulsion then is sprayed on the vegetation to be controlled.
For reasons of economy and safety to the environment and the herbicide applicator, the salt forms of an herbicide often are the preferred form of these herbicides. The salt forms of these herbicides are provided as concentrated aqueous solutions that are diluted with water. However, some water-soluble, solid forms of the salt form of these herbicidal compounds also are available. The solid forms typically are water-soluble, solid products containing essentially only the herbicide (see Champion et al. U.S. Pat. No. 5,266,553), as opposed to water-insoluble granular products. Also, see Flahine U.S. Pat. No. 5,965,487, and Mulqueen et al. U.S. Pat. Nos. 5,374,603 and 5,436,223.
In addition, granule herbicides are prepared by impregnating a substrate with a highly concentrated aqueous solution of the herbicide salt, which often requires the addition of expensive drying agents, such a corn cob granules or silica, in order to provide a noncaking, dry granular herbicide. The highly concentrated aqueous solution of the herbicide salt used to make the granule herbicide tend to form crystals when stored at relatively cool temperatures, i.e., at temperatures below 40° F. Because the majority of granular herbicide manufacturing is done during the winter months, special heating and mixing of the aqueous herbicide concentrates prior to application onto the substrate is necessary to assure that the substrate is impregnated with the precise loading required by U.S. federal regulations.
The ester and salt forms of herbicides containing an acid functionality traditionally are applied to solid substrates, but suffer in cost and difficulty of manufacture because of the previously mentioned problems of solvent removal, and the need to utilize expensive drying agents. In addition, applying a salt form of the herbicide to a substrate often is not practical or feasible. First, applying an aqueous solution of the salt form of an herbicide to a water-soluble substrate wets substrate surfaces and makes processing difficult. Second, a solid salt form of an herbicide is difficult to apply, and especially to apply evenly, to a solid substrate. In addition, granular herbicides manufactured by adding a solid salt form of an herbicide to a substrate are hygroscopic, which causes clumping and stickiness, and requires addition of a drying agent to the composition.
Therefore, it would be advantageous to provide a highly concentrated, liquid herbicidal composition that can be applied directly to a solid substrate, without dilution or addition of drying agents, to provide a granular herbicide containing the desired herbicide combination in the desired amounts. The concentrated liquid herbicidal composition avoids the need to apply an herbicide solution or a molten herbicide to a substrate, which reduces manufacturing costs and equipment associated with preparing an herbicide solution or melting a solid herbicide, applying the molten herbicide to a solid substrate, and evaporating solvent. It also would be advantageous to provide a concentrated liquid herbicidal composition that exhibits excellent cold storage stability, and can be applied at relatively cool temperatures, compared to present-day herbicidal compositions applied to a granular substrate.
SUMMARY OF THE INVENTION
The present invention is directed to concentrated, liquid herbicidal compositions. The concentrated herbicidal compositions are used in undiluted form to prepare granular herbicides.
More particularly, the present invention is directed to a concentrated, liquid herbicidal composition comprising (a) a first herbicide having an acid functionality in the form of a low volatile ester, (b) a solid second herbicide comprising (i) fluroxypyr in the form of a free acid and/or as a solid ester, and, optionally, (ii) an herbicide having an acid functionality in the form of a free acid, and (c) an aprotic solvent. The composition comprises about 55% to abo
Marshall & Gerstein & Borun LLP
Nufarm Americas Inc.
Pryor Alton
LandOfFree
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