WO1993012652A2

WO1993012652A2 - Stabilized gelled-paste formulations of sulfonylureas and an injection system for their application

Info

Publication number: WO1993012652A2
Application number: PCT/US1992/010556
Authority: WO
Inventors: William Arthur Mccollum, Iii; James Scott Davis; Clarence Gaetano Hermansky
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1991-12-20
Filing date: 1992-12-14
Publication date: 1993-07-08
Anticipated expiration: 1994-06-20
Also published as: WO1993012652A3; AU3243093A; BR9207036A; CA2126312A1; EP0621750A1; JPH07502411A

Abstract

This invention relates to 'gelled-paste' compositions of sulfonylurea herbicides in a chemically stabilized formulation consisting essentially of a sulfonylurea or its agriculturally suitable salt with a salt of a carboxylic or an inorganic acid, or with mixtures of such carboxylic or inorganic acid salts in an aqueous medium and to the process for making such gelled-paste compositions, i.e., crop protection products. This invention also comprises an improved method of direct injection to crops of such crop protection products and an apparatus for the direct injection of said products.

Description

STABILIZED GELLED-PASTE FORMULATIONS OF SULFONYLUREAS AND AN INJECTION SYSTEM FOR THEIR APPLICATION BACKGROUND OF THE INVENTION

This invention comprises "gelled-paste" compositions of sulfonylurea herbicides in an aqueous chemically stabilized formulation which requires vigorous mixing to disperse into aqueous media. This invention also comprises an improved method of direct injection to crops of such highly viscous crop protection products, and a new and improved apparatus for the direct injection of said products.

Sulfonylurea herbicides and chemically stabilized aqueous compositions thereof are known in the literature. For instance, U.S. 4,936,900 teaches chemically stabilized aqueous sulfonylurea or agriculturally suitable sulfonylurea salt dispersions in salt mediums which retain their effectiveness as herbicides when formulated as aqueous suspensions consisting of a sulfonylurea or its agriculturally suitable salt with a salt of a carboxylic or an inorganic acid, or with mixtures of such carboxylic or inorganic acid salts. The present invention teaches the gellation of sulfonylureas in salt mediums thereby preserving the stability of the typically unstable sulfonylurea.

SUMMARY OF THE INVENTION

The present invention teaches aqueous, chemically stabilized, gelled-paste compositions of sulfonylurea herbicides. These herbicidal compositions are prepared from a suspension of the type described by U.S. 4,936,900 by the addition of a water-soluble or water- swellable synthetic, semisynthetic or biological polymer(s) which retains its gel characteristics in salt mediums and which does not adversely affect the chemical stability of the sulfonylurea or agriculturally suitable salt of the suspension.

One embodiment of the present invention is a process for making a sulfonylurea herbicide gelled- paste composition, comprising combining a sulfonylurea herbicide and one or a mixture of agriculturally suitable salts of a carboxylic or inorganic acid in an aqueous medium to form a stable dispersion of the resultant sulfonylurea salt in the aqueous medium, then blending one or more gelling agents into said dispersion in sufficient amount to form a gelled-paste composition, which gelling agent is inert with respect to said herbicide. Another embodiment of the present invention comprises an aqueous herbicidal gelled-paste sulfonylurea composition comprising, in admixture, in weight percent based on total formulation weight:

(a) 1-60% of one or a mixture of sulfonylurea herbicide active ingredien (s) ,

(b) 1-40% of one or a mixture of agriculturally suitable salts of a carboxylic or inorganic acid, provided that the solubility of such carboxylic or inorganic acid salts in water at 5°C and a pH of about 6-10 is greater than or equal to 3% and further provided that the pH of a 0.1 molar solution of the carboxylic or inorganic acid salt is between 6 and 10,

(c) 0.5-20% of one or a mixture of a water- soluble or water-swellable synthetic, semisynthetic or biological polymer and that the water-soluble or water- swellable synthetic, semisynthetic or biological polymer(s) used to form the gelled-paste is compatible with the carboxylic or inorganic acid salts and does not lead to chemical decomposition of the sulfonylurea or its agriculturally suitable salt,

(d) 0-10% of one or a mixture of dispersant, and (e) an aqueous medium forming the balance; the sulfonylurea; polymer and aqueous medium in amounts effective to form a gelled-paste composition, provided that the sum of components (a) and (b) is no greater than 85%. A further embodiment of the present invention comprises an aqueous herbicidal gelled-paste sulfonylurea composition comprising, in admixture, in weight percent based on total formulation weight: 1-85% of one or a mixture of stablized sulfonylurea herbicide,

0.5-20% of one or a mixture of water-soluble or water-swellable synthetic, semisynthetic or biological polymer,

0-10% of dispersant, and an aqueous medium forming the balance; the sulfonylurea, polymer and aqueous medium in amounts effective to form a gelled-paste composition.

The compositions of this invention may also optionally contain other water-soluble or water- insoluble pesticides or crop protection chemicals, more specifically, pesticides selected from the class of herbicides, fungicides, bactericides, insecticides, insect antifeedants, acaricides, miticides, nematocides, and plant growth regulants. This invention further comprises an apparatus for direct injection of highly viscous crop protection products for agricultural uses. This invention provides a means by which typical soluble agricultural product forms, as well as atypical, non-traditional, agricultural product forms (highly viscous insoluble gels and pastes) , which would otherwise not be dispersible into a carrier medium, can be dispersed into a carrier medium.

This apparatus comprises, in combination: (a) one or a plurality of container means for housing crop protection product having an optional inlet opening, and having an outlet opening,

(b) pressure means associated with said container means for applying pressure to said crop protection product within said container means for dispensing of said crop protection product through said opening in said container means,

(c) a mixing chamber, interconnected to said opening in the container means, having a first inlet opening for receiving the crop protection product displaced from said opening of said container means, and a second inlet opening for permitting entry of a carrier medium for said crop protection product, and an outlet opening, (d) shearing means positioned within said mixing chamber for dispersing said crop protection product into said carrier medium to produce a sprayable dispersion,- and

(e) means for forcing a sprayable dispersion out of the outlet opening of said mixing chamber to be available for application onto agricultural crops.

The preferred container means is a cartridge which is cylindrical in shape with an opening at one end thereof, said cartridge having a ram positioned within said cylindrical shape remote from said opening, being capable of displacement toward said opening to provide pressure. Said ram operates as a plunger for exerting said pressure.

This invention is also directed to a method for treating agricultural crops comprising the steps of: providing a source of crop protection product in an extrudable form, forcing a measured amount of crop protection product from said source into a mixing zone, introducing a liquid carrier medium into said mixing zone, shearing the crop protection product together with the liquid carrier medium in said mixing zone to disperse said crop protection product within said liquid carrier medium in said mixing zone, and spraying the resulting mixture as it is formed onto the agricultural crop.

The injection method and apparatus provided by the present invention offers advantages for applying crop protection product in mediums such as gels and pastes. These forms of the crop protection product are extrudable from the outlet opening of the container means, in the sense that if the container means were not connected to the interconnection means, the extruded crop protection product would tend to maintain its extrudate shape without external assistance. This enables the crop protection product to be supplied to the application site in concentrated form without tendency to phase separate in said container or to leak from the container in which it is supplied. The invention uses a design whereby all the crop protection product, and some or all of a carrier medium, is exposed to an energy intense zone (shear zone) so that sufficient mechanical energy is imparted to the product to insure dispersion into the carrier medium.

After exiting the shear zone, this dispersed crop protection product is comparable to crop protection product in traditional solutions. Other application devices disclosed in the art fail to accomplish this result. BRIEF DESCRIPTION QF THE DRAWINGS Other features and advantages of the present invention will become more fully apparent from the following detailed description of the appended claims and the accompanying drawings. Figure 1 is a schematic cross-sectional side view of apparatus according to the invention. Figure 2 is a schematic cross-sectional side view of apparatus with a plurality of containers, according to the invention. DETAILED DESCRIPTION OF THE INVENTION

The advantages offered by the novel gelled-paste compositions herein disclosed are both functionally and environmentally attractive relative to other traditional product forms such as liquids, suspensions, granules and powders. The gelled-paste product form described by the present invention reduces risk of point source contamination and user exposure associated with pouring and handling of agricultural products. It is also non-dusty and spill resistant and offers improved shelf stability over traditional aqueous suspensions, in that the dispersed solid particulates are locked-up in a gel matrix and not able to settle, remaining uniform in active concentration throughout the container during storage. Preferred compositions of the invention are:

(1) Compositions wherein the weight percent of the components are: 10-50% of a sulfonylurea herbicide and optionally, at least one additional agricultural pesticide; 5-40% of an agriculturally suitable salt of a carboxylic or inorganic acid; 0.5-10% of a water- soluble or water-swellable synthetic, semisynthetic or biological polymer(s); and 1-10% of a dispersant.

(2) Compositions of Preferred 1 wherein the weight percent of the components are: 10-40% of a sulfonylurea herbicide and optionally, at least one additional agricultural pesticide; 5-25% of an agriculturally suitable salt of a carboxylic or inorganic acid; 0.5-5% of a water-soluble or water- swellable synthetic, semisynthetic or biological polymer; and 1-5% of a dispersant.

(3) Compositions of Preferred 2 wherein the weight percent of the components are: 20-40% of a sulfonylurea herbicide and optionally, at least one additional agricultural pesticide; 10-25% of an agriculturally suitable salt of a carboxylic or inorganic acid; 0.5-2% of a water-soluble or water- swellable synthetic, semisynthetic or biological polymer; and 1-2% of a dispersant.

(4) Compositions of Preferred 3 wherein the water-soluble or water-swellable synthetic, semisynthetic or biological polymer is selected from the group consisting of alginates, alkali metal alginates, acrylic and methacrylic acids, acrylamides, ioto lambda carrageenans, cellulose gums and- their derivatives, N-vinyl-2-pyrrolidinone, starches and their derivatives, and xanthan gums.

(5) Compositions of Preferred 4 wherein the water-soluble or water-swellable synthetic, semisynthetic or biological polymer is selected from the group consisting of alginates, alkali metal alginates, acrylic and methacrylic acids, acrylamides, ioto lambda carrageenans, N-vinyl-2-pyrrolidinone, aluminum or calcium cross-linked carboxymethyl cellulose, and starches and their derivatives. (6) Compositions of Preferred 4 wherein the cellulose is carboxymethyl cellulose.

(7) Compositions of Preferred 4 wherein the cellulose is hydroxyethyl cellulose. (8) Compositions of Preferred 5 wherein the cellulose is an aluminum cross-linked carboxymethyl cellulose.

(9) Compositions of Preferred 5 wherein the cellulose is a calcium cross-linked carboxymethyl cellulose.

(10) Compositions of Preferred 4 wherein the starch is derivatized with a synthetic acrylamide and sodium or potassium acrylate polymer. (11) Compositions of Preferred 4 wherein the polymer is xanthan gum.

(12) Compositions of Preferred 4 wherein the sulfonylurea herbicide is selected from the group: chlorsulfuron; sulfometuron methyl; chlorimuron methyl; metsulfuron methyl; methyl 2-[ [ [ [ (4, 6-dimethoxy-2- pyri idinyl) ino]-carbonyl] mino]sulfonyl]-6- (trifluoro ethyl)-3-pyridinecarboxylate; ethamet- sulfuron methyl; triasulfuron; ethyl 5-[[[[(4,6- dimethoxy-2-pyrimidinyl) amino] carbonyl]amino] sulfonyl] - l-methyl-lH-pyrazole-4-carboxylate; N- [ [ (4, 6-dimethoxy- 2-pyrimidinylamino]carbonyl] -3-(ethylsulfonyl)-2- pyridinesulfonamide; thifensulfuron methyl; tribenuron methyl; bensulfuron methyl; nicosulfuron; and methyl 2-[ [[ [[4, 6-bis (difluoromethoxy-2-pyrimidinyl]amino]- carbonyl]amino]sul onyl]benzoate.

(13) The process wherein the gelled-paste is comprised of, in weight percent based on total formulation weight:

(a) one or a mixture of sulfonylurea in the amount of 1-60% of active ingredient,

(b) one or a mixture of salts of a carboxylic or inorganic acid, in the amount of 1-40% provided that the solubility of carboxylic or inorganic acid salts in water at 5°C and a pH of about 6-10 is greater than or equal to 3% and further provided that the pH of a 0.1 molar solution of the carboxylic or inorganic acid salt is between 6 and 10,

(c) one or a mixture of water-soluble or water-swellable synthetic, semisynthetic or biological polymers in the amount of 0.5-20%,

(d) 0-10% of a dispersant, and

(e) an effective amount of an aqueous medium.

(14) The process of Preferred 13 wherein said gelling agent is blended into the dispersion by the stirring of said dispersion at sufficiently low shear so that said gelled-paste is not broken up as it is formed.

(15) Compositions of Preferred (3) wherein the sulfonylurea herbicide and additional pesticide component is selected from the group consisting of nicosulfuron and bromoxynil, chlorimuron ethyl and metsulfuron methyl, and metsulfuron methyl and 2,4-D. The term "sulfonylurea herbicide" is meant to include the entire class of sulfonylurea herbicides, that is those compounds containing the following and any closely related functionalities.

o II

-S0₂NHCN—

The preparation of sulfonylurea herbicides is known in the art, e.g., see U.S. 4,127,405 and U.S. 4,169,719. Agriculturally suitable salts of sulfonylureas are also useful herbicides and can be prepared in a number of ways known in the art. For example, metal salts can be made by treating sulfonylureas with a solution of an alkali metal salt having a sufficiently basic anion (e.g., hydroxide, alkoxide, carbonate or hydride) . Ammonium and substituted ammonium salts can also be made by similar techniques. Cation exchange to form the agriculturally suitable sulfonylurea salt where the sulfonylurea acid or salt is directly treated with an aqueous solution containing the cation to be exchanged is also known in the art. Cation exchange can also be effected by passing an aqueous solution of the sulfonylurea salt through a column packed with a cation exchange resin. U.S. 4,936,900 teaches that stabilized aqueous suspensions of compounds of sulfonylurea herbicide active ingredients can be prepared when the aqueous suspending medium contains ammonium, substituted ammonium or alkali metal salts of a carboxylic acid or an inorganic acid or mixtures of such salts provided that the solubility of those salts at pH 6-10 is greater than or equal to 3% at 5°C, and further provided that the pH of a 0.1 molar aqueous solution of the carboxylic or inorganic acid salt is between 6 and 10.

The salts which are preferred in the aqueous medium are ammonium, substituted ammonium or alkali metal salts of a carboxylic or an inorganic acid which are soluble in water at 3% or more at 5°C. The useful concentration range is from 3% to the saturation point at 5°C. The preferred salts of the invention will further possess a pH between 6 and 10 for a 0.1 molar aqueous solution. Examples of these salts are diam onium hydrogen phosphate, ammonium acetate, lithium acetate, sodium thiocyanate, sodium acetate, potassium acetate, or compatible mixtures thereof. Diammonium hydrogen phosphate and sodium acetate are preferred for compositions containing the ammonium and sodium salts, respectively, of the salts of the sulfonylurea herbicide. The useful pH range of these compositions is 6-10 although 7-9 is preferred. In most cases, the salts described above automatically produce a formulation with the desired pH. The anion of the carboxylic or inorganic acid salt may act as an acid acceptor and generate in situ the salt of the sulfonylurea herbicide from its corresponding conjugate acid.

The formulations of this invention contain about 1 to 50%. (preferably 10 to 40%) of the compounds of the sulfonylurea herbicide active ingredients suspended in an aqueous solution which contains from 3% to the salt saturation amounts of an agriculturally suitable salt of a carboxylic or an inorganic acid or mixtures thereof as described above. Preferred concentrations of these carboxylic or inorganic acid salts are in the range of about 10-40% in the aqueous phase.

U.S. 4,936,900 discloses the need for dispersants to insure proper wetting and dispersing characteristics. The term "dispersant" is meant to include common wetting and dispersing agents such as trimethylnonyl polyethylene glycol ether, sodium alkylnaphthalenesulfonates, sodium alkylbenzenesulfonates, sodium dioctyl sulfosuccinate, sodium dodecyl sulfate, the ammonium and sodium salts of lignosulfonic acid and formaldehyde condensates of naphthalenesulfonic acid.

The present invention incorporates the use of at least one synthetic, semisynthetic or biological polymer which is water-soluble or water-swellable, which will retain its utility as a gelling agent in the presence of ammonium or alkali metal salts of a carboxylic or an inorganic acid allowing the consistency of the aqueous sulfonylurea or agriculturally suitable salt suspension to be altered to that of a gelled-paste without a detrimental effect on the chemical stability of the sulfonylurea or its agriculturally suitable salt, as determined by comparison to a reference sample which does not contain polymer. In this invention the term "water-soluble or water-swellable synthetic, semisynthetic or biological polymer" includes macromolecules which form hydrogels, have weight average molecular weights ranging from several thousands to millions, and retain their functionality in the presence of carboxylic or inorganic acid salt or mixtures thereof.

Examples of polymers which can form hydrogels include, but are not limited to, alginates and alkali metal alginates, acrylic and methacrylic acids, glycerol methacrylates, acrylamides, ioto and lambda carrageenans, cellulose gums and their derivatives (e.g., carboxymethyl cellulose and hydroxyethyl cellulose) , poly(CHEMA) , copolymers of W-vinyl-2- pyrrolidinone, starches and their derivatives (e.g., naturally occurring starch derivatives with a synthetic acrylamide and sodium or potassium acrylate polymer) , and xanthan gums.

An additional requirement for the selection of polymers which are suitable as gelling agents in this invention is chemical and physical compatibility with the sulfonylurea present in solution and as particles of the paste. The identification of polymers with suitable characteristics is detailed below. Polymers which are not suitable for use in this present invention are polymers which do not form hydrogels in salt environments or which chemically destabilize sulfonylureas.

For many polymers the adverse effect of salts on their ability to form gels in aqueous solutions is known in the art. Product literature available from most vendors of polymeric materials and the following reference contain such information, Handbook of Water Soluble Gums and Resins, Robert L. Davidson, Ed. McGraw-Hill, 1908. The gelled-pastes of this invention can also be appled directly to the locus to be protected without prior dissolution or dispersion into a spray solution. For example, a spot gun may be used to directly apply the gelled-paste at the base of a tree of into the soil.

The gelled-pastes of this invention do not compromise performance when used with mechanical mixing devices which insure incorporation of the gelled-paste into a spray solution.- When finely dispersed, these compositions can be sprayed through conventional spray nozzles in which 50 mesh screens precede each nozzle to protect it from blockage. hen dispersed the gelled- pastes of this invention have been shown to be as biologically effective as the control dispersion (no polymer) in greenhouse testing.

The gelled-pastes of this invention can also be applied directly to the locus to be protected without prior dissolution or dispersion into a spray solution. For example, a spot gun may be used to directly apply the gelled-paste at the base of a tree or into the soil.

The gelled-pastes detailed in this invention are obtained by the combination of the techniques detailed in U.S. 4,936,900 with the selection of appropriate water-soluble or water-swellable synthetic, semisynthetic of biological polymer(s). In accordance with the process of U.S. 4,936,900, it is known in the art that polymers (organic macromolecules) , clays, silicas and silicates can be used, alone or in combination, as thickening or suspending agents for aqueous suspensions.

In the agrichemical art, thickeners are used to thicken agrichemical liquid formulations but still leave them pourable, so as to be adaptable for addition to mixing tanks and dispersible therein when mixed with water.

It is also known in the art that polymer thickeners are more effective thickening agents than are the inorganic thickeners, requiring 0.01 to 0.2 percent (polymer) vs. 0.5 to 5% (inorganics) to achieve the desirable antisettling characteristic associated with thickened aqueous suspensions.

The present invention involves not only the selection of certain polymers for gelling the herbicide composition so as to render it nonflowable, but also the selection of the use of such polymer in a greater amount than used as a thickener and incorporation into the composition in a manner which permits the gellation to occur.

The polymers useful in this invention retain their identity as gelling agents in the presence of salt and sulfonylurea particulates while simultaneously preserving the chemical stability of the sulfonylurea or agriculturally suitable sulfonylurea salt. The novel gelled-pastes of the present invention are rigid and cannot readily be diluted into water unless they are mechanically sheared first.

Addition of the polymer at any step in the preparation of the composition is acceptable, provided the polymer does not degrade during the wet milling step, per U.S. 4,936,900. If stability to wet milling is not known, the effect of mechanical energy on the polymer in question can be determined by comparing the properties of a formulation made by pre- and post- milling addition of the polymer.

By adjusting the amount of polymer, the desired gelled-paste consistency can be obtained. Optimization of this consistency can be accomplished by visual observation and experimental measurement. Two measures of the gelled-paste strength have been used to quantify the extent of gellation, viscosity and yield stress measurements. In the Examples of this invention, both the viscosity and yield stress were measured using a rotational viscometer. Standard instruments are readily available from various companies, such as Haake, Contraves, Carri-Med, Bohlin and Brookfield. Both the instrument and accompanying geometry (parallel plate, cone and plate, concentric cylinder sample compartments) can be used to accurately measure yield stress and viscosity by one of the following techniques.

Either a fixed shear rate can be imposed on a sample and the resulting stress measured, or a controlled stress can be imposed on a sample and the resulting shear rate measured. Regardless of the method chosen, a plot of the shear rate vs. stress can be constructed and analyzed, to extract the plastic viscosity and yield stress of the sample, by applying the Bingham Equation. This is done by fitting the linear portion of the data to the equation. The slope of the plot gives the plastic viscosity of the sample and the intercept of the plot gives its yield stress. A more in-depth review of the art can be found in many texts on viscometry, rheology or rheometry. The following references contain such information: 1) K. Walters, "Rheometry: Industrial Applications", Research Studies Press (1980), 2) P. Sherman, "Industrial Rheology", Academic Press (1970), 3) T. C. Patton, "Paint Flow and Pigment Dispersion", Wiley (1979) . Geometric constants, equations and instrumentation to automate instrument operation and calculation are routinely supplied with all of the instruments mentioned above.

In general, the plastic viscosity and yield stress of a gelled-paste will be higher than that of a suspension which does not contain a gellant. Thus, the measurement of yield stress and plastic viscosity can be used to evaluate the degree of gellation or the strength of the gelled-paste under consideration.

In the instant invention, visual observation, plastic viscosity, yield stress and chemical stability of the active sulfonylurea herbicide or its agriculturally suitable salt were used to establish that a suitable polymer had been selected, i.e., one which gave a physically suitable gelled-paste composition in which the chemical stability of the sulfonylurea or agriculturally suitable sulfonylurea salt was not diminished relative to that of the aqueous high salt suspension which did not contain the polymer used to form the gelled-paste. The aqueous high salt suspension which did not contain the gellant is referred to as the control or reference sample in the Examples which follow. Physical Measurements

G. G. Hawley's, "The Condensed Chemical Dictionary," 10th Edition, Van Nostrand Reinhold Company, defines a gel as "a colloid in which the dispersed phase has combined with the continuous phase to produce a viscous, jelly-like product." Consistent with this definition, an aqueous suspension not containing an effective "gellant" is thin and fluid¬ like, and eventually phase separate on storage at ambient temperature. In contrast, an effective gellant produces a combination of continuous phase and dispersed phase interactio (s) leading to a viscous, jelly-like product.

For the purpose of physically characterizing the aqueous suspensions, and the gelled-pastes of this invention, the effectiveness of a given polymer(s) was visually assessed by using one or more of the following criteria: i. Rigidity, reflected by the gelled-paste's ability to retain a deformation over an observed time frame of several minutes, for example upon separating (pulling apart) two plates between which a gelled-paste of thickness about 1 mm has been placed, the gelled- paste shows and retains a unique solid-like form and resists flow under its own weight as evidenced by the persistence of a macroscopic form or "structure" (ridges) . ii. Resiliency, elastic "jelly-like" or "toothpaste-like" consistency, the latter being more descriptive of a gel which contains suspended particles. iii. Resistance to movement (flow) as determined by little or no movement of the sample on tilting, iv. Little or no phase' separation over time. v. Requires vigorous mixing to disperse into aqueous media.

A more quantitative method by which the effectiveness of a polymer is determined is the measurement of viscosity and yield stress. This technique was also used to characterize the gelled- pastes of this instant invention and required that the rheological response of the sample be evaluated by conventional rotational rheometry techniques. For the purpose of this invention, a controlled stress rheometer equipped with a standard, calibrated, cone and plate geometry was used.

For the liquid-like, control dispersions, a range of stress from 0.1-10 Pa was applied to the sample in 20 logarithmic steps, from lowest to highest, with each stress allowed to act on the sample for 30 seconds before the next higher stress was applied. The same procedure was used for the gelled-paste samples with one exception, the applied stress range was shifted from 10-100 Pa to accommodate the increased stiffness of the gelled-paste samples. The Bingham Equation was applied to each data set, as previously described to calculate yield stress and plastic viscosity. Chem cal Measurements Once an acceptable polymer was identified, based on the physical characteristics described, the original gelled-paste and control (no gellant) samples were stored side-by-side in sealed containers for 3 weeks at 0-55°C. Upon removal, both sample sets were assayed for sulfonylurea or sulfonylurea salt content and the results compared to determine the chemical suitability of the polymer.

The correct selection of polymer is determined as follows. The gelled-paste is compared to a reference sample, wherein the reference sample contains water in place of polymer; a) the polymer is selected by visual inspection, in which the beneficial effect of the invention is demonstrated by an increase in rigidity, consistency, resiliency, resistance to flow, and reduced phase separation relative to the reference, or b) the polymer is selected by viscosity measurement, in which the beneficial effect of the invention is demonstrated by an increase in viscosity over that of the reference dispersion which does not contain a gellant, or c) the polymer is selected by yield stress measurement, in which the beneficial effect of the invention is demonstrated by an increase in yield stress over that of the control dispersion which does not contain a gellant.

The group of sulfonylureas selected to illustrate the novel gelled-paste formulations of this invention are listed below by their common name. For the purpose of the following examples, these sulfonylureas will be hereafter referred to by the compound numbers: I = chlorsulfuron, II = metsulfuron methyl, III = thifensulfuron methyl, and IV = tribenuron methyl. The preparation of stable gelled-paste compositions can be separated into two separate steps, formation of the dispersion, followed by the addition of the gelling agent(s).

A preferred technique for the preparation of stabilized dispersions is described in U.S. 4,936,900. In accordance with this procedure the sulfonylurea is suspended in water and a dispersant, thickener or suspending agent is added. The mixture is then treated with a desired base such as ammonium or sodium hydroxide to a pH of 6.0-10.0, preferably 7.0-9.0, and then treated with an insolubilizing salt, such as a carboxylic or inorganic acid salt(s), with agitation. The insolubilizing salt decreases the solubility of the sulfonylurea causing the sulfonylurea to precipitate out of solution. This method of preparation has been adopted in the present invention. Since the dispersion was to be gelled, the thickener was excluded from the composition. All salts were added incrementally to the neutralized conjugate acids in order to develop the precipitated sulfonylurea and sulfonylurea salt slowly and avoid the formation of a tacky solid or gum, per U.S. 4,936,900. The resulting suspension was then bead-milled to a particle size of 1-20 microns, pre erably 1-8 microns. A gelling agent or mixture of gelling agents, water soluble or water swellable synthetic, semisynthetic or biological polymer(s), were added after the milling step was completed to avoid the risk of degradation of the polymer during a high shear milling step.

The gelling agents selected to illustrate the novel gelled-paste formulations of the instant invention are listed below. Specific commercial products from each class are referred to by name and source. In the following Examples, all polymers are referred to by commercial or trade name.

Xanthan Gum - Kelzan®, a product of Kelco Corp., was selected to demonstrate the utility of water soluble biopolymers/gums. Modified Starch - SGP147® ("Super Slurper"), a product of Henkel Corp., was selected to demonstrate the utility of water swellable starches.

Cellulose - CMC-7L® and CMC-7M®, a product of Hercules, Inc., low(L) and mediu (M) molecular weight carboxymethyl derivatives of cellulose, were selected to demonstrate the utility of cellulosics.

Examples 1-10 illustrate the utility of the above polymers with a variety of sulfonylurea actives, at a sulfonylurea concentration of approximately 19-21% by weight. Examples 11-14 illustrate the utility of the invention at higher sulfonylurea content and under conditions wherein the stabilizing salt level and identity have been changed.

In all cases where a composition is not referred o as a control it contains a gellant or gellant system 21 and will be classified as a gelled-paste. In all the Examples which follow, the gelled-pastes can be visually described as being rigid and resilient, exhibiting a range of elastic character and viscosities which are consistently greater than that of the control dispersion. -

Modified Starch (Super Sluiper) 1.9

The sodium alkylnaphthalenesulfonate was dissolved in about 80-90% of the total water, at room temperature, with stirring. Compound I was added incrementally, in three equal portions, and allowed to disperse well. The 50% aqueous sodium hydroxide solution was then added slowly over a 15 min. period with stirring to form the salt of Compound I. Where anhydrous sodium acetate is indicated, it was added in three steps, in a 1:1:2 ratio by weight. The additions were made at 30, 45 and 55 min. during which time the slurry was continually being stirred. The dispersion was then bead-milled for 30 min. Upon completion, the pH of the milled dispersion was adjusted to 8.4 using a dilute HC1 solution and the gelling agent and/or water were added to achieve the above statement of composition. The final mixture was stirred until visually homogeneous. The yield stress and plastic viscosity of each composition were measured as previously described. The results are tabulated below.

System

Control A (No Salt) Control B (No Gellant) No. 1 Kelzan® No. 2 Super Slurper

To determine chemical stability and acceptability of physical properties, all samples were aged at 45°C for 3 weeks. After aging, their visual appearance and chemical properties were assessed and compared.

Both aged and unaged control samples (A and B) settled leaving a brownish supernatant phase atop the dispersion within a day, whereas, the gelled systems showed little or no tendency to form a supernatant over the three week period of the experiment. Greater than 10% relative decomposition of Compound I occurred during the 3 week, 45°C oven aging of Control A, due to the absence of the stabilizing carboxylic or inorganic acid salt. No detectable decomposition of active ingredient occurred during 3 week storage at 45°C in the Control B sample which contained the stabilizing sodium acetate carboxylic acid salt. Likewise, no detectable decomposition was seen in sample No. 1

(Kelzan®) or No. 2 (Super Slurper) . From these data the ability to gel a dispersion of sulfonylurea with a polymer which is functional in high salt medium without significant decomposition of the sulfonylurea active, is demonstrated. EXAMPLES 3 TO 5

Ingredients

Compound I sodium alkylnaphthalenesulfonate

Aqueous 50% Sodium Hydroxide

Sodium Acetate (Anhydrous)

Water

Gelling Agent Carboxymethyl Cellulose (CMC-7M®)

Carboxymethyl Cellulose (CMC-7L®)

Crosslinking Agent Aluminum

Acetate Monobasic

The compositions were processed per Examples 1 and 2. Upon completion of the bead-milling step, the pH of the milled dispersion was adjusted to 8.4 using a dilute HC1 solution. The gelling agent was then added followed by water and/or water plus the Aluminum Acetate Monobasic, per the above statement of composition. The final mixture was stirred until visually homogeneous.

The yield stress and plastic viscosity of each composition were measured as previously described. The results are tabulated below.

System

Control C (No Gellant)

No. 3 CMC-7M®

No. 4 CMC-7L®

No. 5 Cross-linked CMC-7L®

To determine chemical stability and acceptability of physical properties, all samples were aged at 45°C for 3 weeks. After aging, their visual appearance and chemical properties were assessed and compared. The control sample settled leaving a brownish supernatant phase atop the dispersion within a day, whereas, the gelled systems showed little or no tendency to form a supernatant over the three week period of the experiment. No decomposition of the active was detected in the control or gelled samples as a result of the 45°C oven aging. From these data the ability to gel a dispersion of sulfonylurea with a polymer which is functional in high salt medium and which can be cross-linked to provide greater gel strength without significant decomposition of the sulfonylurea active is demonstrated.

EXAMPLE 6

Composition (Percent by Weight)

Ingredients Compound II sodium alkylnaphthalenesulfonate

Aqueous 50% Sodium Hydroxide

Sodium Acetate (Anhydrous)

Water

Carboxymethyl Cellulose (CMC-7 ®)

The compositions were processed per Examples 1 and 2. Upon completion of the bead-milling step, the pH of the milled dispersion was adjusted to 8.0 using a dilute NaOH solution and the gelling agent and/or water were added to achieve the above statement of composition. The final mixture was then stirred until visually homogeneous. The yield stress and plastic viscosity of each composition were measured as previously described. The results are tabulated below.

To determine chemical stability and acceptability of physical properties, all samples were aged at 45°C for 3 weeks. After aging, their visual appearance and chemical properties were assessed and compared. The control sample settled leaving a brownish supernatant phase atop the dispersion within a day, whereas, the gelled systems showed little or no tendency to form a supernatant over the three week period of the experiment. Nine percent relative decomposition of the active was measured in the control sample after 3 weeks storage at 45°C. Less than 4%. relative decomposition was measured in the CMC-7L® gelled-paste stored at 45°C for 3 weeks. From these data the ability to gel a dispersion of sulfonylurea with a polymer which is functional in high salt medium without significant decomposition of the sulfonylurea active is demonstrated.

EXAMPLES 7 TO 8

Composition Percent b Wei ht

Ingredients

Compound III sodium alkylnaphthalenesulfonate

Aqueous 50% Sodium Hydroxide

Sodium Acetate (Anhydrous)

Water

Gelling Agent Xanthan Gum (Kelzan®)

Carboxymethyl Cellulose (CMC-7L®)

Crosslinking Agent - Aluminum

Acetate Monobasic The compositions were processed per Examples 1 and 2. Upon completion of the bead-milling step, the pH of the milled dispersion was ound to be 8.1 and was not further adjusted. The gelling agent was added, followed by water and/or water plus the Aluminum Acetate Monobasic, per the above statement of composition. The final mixture was stirred until visually homogeneous.

Yield Stress Plastic Viscosity System (Pascals) (PascalrSeoonds)

Control E (No Gellant) 0.06 0.03

No. 7 Kelzan® 81.0 6.1

No. 8 Cross-linked CMC-7L® 96.5 2.2

To determine chemical stability and acceptability of physical properties, all samples were aged at 45°C for 3 weeks. After aging, their visual appearance and chemical properties were assessed and compared. The control sample settled within a day whereas, the gelled systems showed little or no tendency to form a supernatant over the three week period of the experiment. Less than 4% relative decomposition of active was found in all samples after 3 week aging at 45°C. From these data the ability to gel a dispersion of sulfonylurea with a polymer which is functional in high salt medium and which can be cross-linked to provide greater gel strength without significant decomposition of the sulfonylurea active is demonstrated. EXAMPLES 9 TO 10

Composition Percent b Wei ht

Ingredients

Compound IV sodium alkylnaphthalenesulfonate

Aqueous 50% Sodium Hydroxide

Sodium Acetate (Anhydrous)

Water

Gelling Agent Modified Starch 3.8 (Super Slurper)

Carboxymethyl Cellulose (CMC-7L®) 3.8

The compositions were processed per Examples 1 and 2. The pH of the bead-milled dispersion was then adjusted to 8.2 with a dilute solution of sodium hydroxide and the gelling agent and/or water were added to achieve the above statement of composition. The final mixture was stirred until visually homogeneous.

system

Control F (No Gellant) No. 9 Super Slurper No. 10 CMC-7L®

To determine chemical stability and acceptability of physical properties, all samples were aged at 45°C for 3 weeks. After aging, their visual appearance and chemical properties were assessed and compared. The control sample settled leaving a brownish supernatant phase atop the dispersion within a day whereas, the gelled systems showed little or no tendency to form a supernatant over the three week period of the experiment. Less than 5% relative decomposition of active occurred in the control sample, while 14-29% relative decomposition was found in the gelled samples after storage for 3 weeks at 45°C.

The increased decomposition rate for the gelled- pastes of Compound IV over that of the control sample is characteristic of the enhanced instability of Compound IV active which is easily decomposed by trace nucleophilic impurities such as those which could enter into a gelled-paste through the addition of the polymer.

EXAMPLES 11 TO 12

Modified Starch (Super Slurper) — — 1.0

Using Compound I at about 40% active, Examples 11 and 12 represent higher active ingredient levels than thus far exemplified. The sodium acetate content has also been dropped from 20% to 10% to accommodate the increased active content.

The compositions were processed per Examples 1 and 2. The pH of the bead-milled dispersion was then adjusted to 7.5 with a dilute solution of sodium hydroxide and the gelling agent and/or water were added to achieve the above statement of composition. The final mixture was stirred until visually homogeneous. The yield stress and plastic viscosity of each composition were measured as previously described. The results are tabulated below.

System

Control G (No Gellant)

No. 11 Kelzan®

No. 12 Super Slurper

To determine chemical stability and acceptability of physical properties, all samples were aged at 45°C for 3 weeks. After aging, their visual appearance and chemical properties were assessed and compared to the control. The control sample settled leaving a brownish supernatant phase atop the dispersion within a few days, whereas, the gelled systems showed little or no tendency to form a supernatant over the three week period of the experiment. Less than 3% relative decomposition of active occurred in the control and gelled samples, after 3 week aging at 45°C. From these data the ability to gel a 40% active dispersion of sulfonylurea with a polymer which is functional in high salt medium and which does not destabilize the sulfonylurea active of interest, even in a gelled-paste in which the sodium acetate stabilizing salt percentage is reduced to 10%, is demonstrated.

EXAMPLES 13 TO 14

Ingredients Compound II sodium alkylnaphthalenesulfonate

Aqueous 50% Sodium Hydroxide

Sodium Acetate (Anhydrous)

Water

Gelling Agent Xanthan Gum

(Kelzan®)

Modified Starch (Super Slurper) 3.9

Using Compound II at about 40% active ingredient, Examples 13 and 14 represent higher active ingredient levels than thus far exemplified. The sodium acetate content was also dropped from 20% to 10%, absolute, to accommodate the increased active content. The compositions were processed per Examples 1 and 2. The dispersion was bead-milled for approximately 30 min. The pH of the milled dispersion was then adjusted to 8.3 with a dilute solution of sodium hydroxide and the gelling agent and/or water were added to achieve the above statement of composition. The final mixture was stirred until visually homogeneous.

The yield stress and plastic viscosity of each composition was not measured. However, the expected range is given in the following table.

Yield Stress Plastic Viscosity

System (Pascals) (Pascal-Seconds)

Control H (No Gellant) 2 - 5 0.2 - 0.5

No. 13 Kelzan® 50 - 500 10 - 800

No. 14 Super Slurper 50 - 300 10 - 2000 To determine chemical stability and acceptability of physical properties, all samples were aged at 45°C for 3 weeks. After aging, their visual appearance and chemical properties were assessed and compared to the control. The control sample settled leaving a brownish supernatant phase atop the dispersion within a few days, whereas, the gelled systems showed little or no tendency to form a supernatant over the three week period of the experiment. Less than 2% relative decomposition of active occurred in the control and gelled samples, during 3 week aging at 45°C. From these data the ability to gel a dispersion of sulfonylurea with a polymer which is functional in high salt medium without decomposing the sulfonylurea active is demonstrated.

The above Examples are presented to illustrate, but in no way limit, the compositions of the present invention.

The direct injection of crop protection products is important in that it enables use of concentrated crop protection products without having to dilute the crop protection products in a large spray tank. This avoids contaminating a spray tank and, thereby, greatly reduces the production of waste from the residue of diluted crop protection products. Also, existing systems have limited viscosity and other physical property ranges due to a lack of an appropriate system component design (Ghate, S. R. and Phatak, S. C, American Society of Agricultural Engineers paper #901056, 1990 International Meeting, Columbus, Ohio; Reichard, D. L. and Ladd, T. L., Transactions of the American Society of Agricultural Engineers 1983, 26(3): 683-686) . The known systems are limited to traditional agricultural product forms (solutions, emulsifiable concentrates, wettable powders and dry flowables) that are prepared by mechanical _.(milling, stirring) and chemical (formulation) means, to insure that the active ingredien (s) disperses or dissolves into the carrier medium when exposed to traditional low intensity tank mix agitation and/or sparging. These products are dissolved or mixed in contact with secondary fluids such as water and oils, or a mixture thereof, the carriers used to transfer the dispersed active ingredients through the spray machine, to a target. These limitations are due to the limited range of physical properties which the dispersing mechanisms can handle.

The prior art requires that crop protection products be readily soluble and/or dispersible in water, emulsions, or oil as a bulk carrier in a two- fluid system. This requirement prohibits direct injection of many useful crop protection products that are not readily soluble or dispersible. This invention provides a new and improved method and apparatus for the direct injection of highly viscous and/or insoluble crop protection products.

In accordance with the invention, and as shown in Figure 1 and Figure 2, the apparatus 5 generally includes displacement means 10, container means 15, manifold 25, solenoid gate 30, mixing chamber 35, and shearing means 40. A quick connect sealing means 20 is mounted between container means 15 and interconnecting means 21. Said quick connect sealing means is depicted in a disconnected position for clarity in Figure 1. Container means 15, has an opening at its front end 16 and optionally at its rear end 17, through which the crop protection product can be loaded into the container means. Application of pressure to the crop protection product within container means 15 dispenses it from said container means 15 through said front end opening and, in turn, through said quick connect sealing means 20 and manifold 25 to the inlet opening 22 of said mixing chamber 35 through interconnecting means 21 at a uniform or variable rate, depending on control desired, as positive pressure is applied to container means 15. Container means 15 may take various sizes and shapes which will allow container means 15 to be sealed so as to be internally pressurizable by internal or external means. Container means 15 may itself contain the crop protection product or may serve as a holder within which a replaceable secondary container or cartridge 7 holding crop protection product is placed.

Container means 15 is adapted by conventional means to be readily replaceable by different containers to thereby enable apparatus 5 to readily dispense a variety of crop protection products with minimal delay due to switching of crop protection products. Container means 15 may also comprise a plurality of like or similar containers for housing crop protection products mounted by conventional means on a container support. Each of the plurality of containers may house a different crop protection product. Container means 15, when removed from apparatus 5, may be used for storing crop protection products.

Container means 15 is used with a pressure means, 10, for applying pressure to the interior of container means 15 to transfer crop protection product from container means 15 to manifold 25 and into mixing chamber 35. Also preferably, container means 15 is in the form of a hollow cylinder that can be pressurized by pressure means 10 that is in the form of a piston consisting of Rod 9 and a piston head 11 mounted on one end of the rod. Head 11 is suitably dimensioned to provide for substantially flush contact with the interior walls of container means 15 or of cartridge 7 when container means 15 is provided with a replaceable cartridge 7.

The interconnecting means 21 may utilize any conventional means of connecting the container means 15 with the mixing chamber 35.

The preferred interconnecting means 21, attached to the front end of container means 15 by means of a quick connect seal 20, is comprised of a manifold 25 and a solenoid gate 30 at the downstream end of interconnecting means 21.

The solenoid gate 30, located downstream of manifold 25 and upstream of mixing chamber 35, is quick acting to shut on-off instantaneously on command. The solenoid is indicated in the drawing by a gate 30 in the closed on-off position. The manifold's 25 role in this device is to facilitate the flow of material from container means 15 to the solenoid gate 30. This device may be a single fitting with a single channel for materials to flow through or a series of channels for multiple materials to flow through simultaneously to meet at or before the solenoid gate 30. The solenoid gate 30 controls the flow of product from the end of one or more channels in manifold 25 to mixing chamber 35. This solenoid gate 30 can be operated manually, electrically or hydraulically. The preferred solenoid gate 30 for this invention is electrically operated.

The pressure means 10 is a device for forcing products from container means 15 by putting pressure on the product. Displacement of the crop protection product may be accomplished by any means that allows for dispensing of substantially all of the crop protection product in the container means at a uniform and consistent rate over a wide range of ambient environmental conditions utilizing a positive pressure differential between the product in container means 15 and the mixing chamber 35. This may be accomplished by, but is not limited to such means as the following methods, mechanical linear actuator hydraulic pressure, compressed air, vacuum, or positive displacement pump.

The preferred pressure means 10 is a device providing energy to positively displace material by means of a DC drive motor/electronic controller actuating a linear ball screw mechanism. A piston drive plate corresponding to piston head 11, attached to the end of the screw engages a piston plunger 9 to dispense product from the container. Mechanical displacement of the drive plate toward the container outlet results in a given volume of product dispensed for a given linear stroke. This results in linear relationship of consistently accurate feed rates metered across the entire operating range of the drive motor, i.e., equal volume dispensed per shaft rotation, independent of the physical properties of the product, such as changes in viscosity. Displacement rates are dependent on dimensions of the container means and gear ratio of the linear ball screw. Limit switches may be employed to monitor and regulate linear stroke length. The mixing chamber 35 allows for the primary medium, crop protection product, in a form such as a gel or paste, introduced from the container means through a first inlet opening 23, to be dispersed and mixed with a secondary carrier medium, such as water and/or vegetable oils, coming under pressure from a source thereof (not shown) via second inlet opening 22. This mixing chamber 35 must be adaptable to the manifold 25, solenoid gate 30 and to the shearing means 40 without leaking liquid when the secondary carrier medium is flowing through the chamber under pressure. The mixing chamber 35 should be of sufficient size and shape to accommodate flows of 0 to 1000 gals per minute under pressures of 0 to 827.4 KPA. The mixing chamber 35 must be of a design so that all the secondary and primary media experience the high shear zone of the mixing chamber. The inlets and outlets of the mixing chamber are sized so as to not restrict the flow volume. Preferably the pressure on the secondary liquid medium, supplied such as by a pump (not shown) which transfers this medium from its source to the mixing chamber, also is sufficient for applying the resultant mixture exiting the chamber via outlet opening 24 to the agricultural crop preferably as a spra . The preferred mixing chamber 35 is a pressurized vessel that houses a shearing means 40 for homogeneously dispersing crop protection product as it is dispensed from container means 15 with the secondary liquid medium. The crop protection product meets with the carrier medium just prior to entering the shear zone of the mixing chamber 35, which zone is defined by the shearing means 40. Overall mixing chamber 35 dimensions are such that a minimum of residence time for the mixture is required prior to exiting the outlet opening 24. The mixing chamber 35 preferably comprises two halves mounted directly to a DC motor drive (not shown) , for shearing means 40, to a position within the chamber and disassembles to facilitate maintenance of the internal components. The shearing means 40 provides for the instantaneous and homogeneous dispersion of the primary material with the secondary medium or carrier. The preferred device consists of a stationary housing, a rotating blade(s) 42 positioned within said housing, said blade(s) having a close tolerance to said housing. There are several conventional shearing devices. In the preferred device, the point at which the dispersion exits (outlet opening 24) is located in such an orientation within the shearing zone so material is sheared as the flow exits the rotating blade 42 and housing interface.

Suitable crop protection products for use with this invention are selected from the group consisting of herbicides, fungicides, insecticides, acaricides, ne atocides, miticides, virusides, algicides, bactericides, and plant growth regulants, and their agriculturally suitable salts. These products can be made into pastes by addition of thickening agents to dispersions or solutions thereof. The pastes can be made into gels by addition of gelling agents, such as gums, thereto. Carrier medium useful in this invention include water and/or vegetable oils. Preferably the carrier medium is aqueous.

GENERAL PROCEDURE The crop protection product can be in the form of a closed capsule or cartridge. The user loads the cartridge into the container means 15. The user then sets a controller to control the rate of dispensing of crop protection product by positive pressure at a setting based on a unit volume/unit time calculation according to the specifications of the crop protection product to be used. The crop protection product is introduced into the mixing chamber 35 and the correct dosage is instantaneously and homogeneously mixed with the secondary medium by the shearing means and sent through outlet opening 24 to nozzles to the target agricultural crop. The housing of shearing means 40 contains one or more exit slots 41 to permit the dispersed crop protection product to flow from shearing means 40 and exit through outlet opening 24 of the mixing chamber 35. Since the crop protection product is instantaneously mixed, the apparatus can be located anywhere downstream of any spray equipment's main tank as convenient and appropriate for installation and the requirements of the installer/user. The preferred location is on the main boom line after the pump and bypass line and before the split to auxiliary boom lines. It is preferable that the apparatus be as close as possible to the nozzle in order to reduce contamination of the equipment.

The cartridge is connected and sealed by the quick connect sealing means at the tip of the cartridge to the solenoid gate. As the crop protection product moves through an electronic solenoid gate which controls the flow of material into the mixing chamber, it comes in contact with the secondary carrier medium. The crop protection product and carrier medium flowing under pressure mix through the shearing zone created by a rotative blade, or other conventional shearing or mixing device. In the preferred invention there are three blades 42 turning at a high rate of revolutions per minute that shear the material (crop protection product plus carrier medium) between the blades and the eight exit slots 41 that the materials pass through before exiting in a homogeneously mixed and finely dispersed or solubilized form into the primary boom of the spray system that the invention is attached to. An electric 12 volt D.C. motor drives the blades of the shearing means. The resulting mixture is forced out of outlet opening 24 and then is released through the spray nozzles where it is sprayed onto the target.

An example of a gel composition containing a crop protection product to be used in this device is shown below: Composition (Pfrr-r.Px.r hy We rht)

1. chlorsulfuron (herbicide) 18.4

2. sodium alkylnapthalenesulfonate 0.9 3. aqueous 50% sodium hydroxide 4.0

4. sodium acetate (anhydrous) 18.1

5. water 56.6-58.1

6. carboxymethyl cellulose (CMC-7L®) 0.5-2.0

The herbicide is mixed with ingredients 2-5 mentioned above under conditions of high shear as described in U.S. 4,936,900 to form an aqueous dispersion or paste of the chlorosulfuron, followed by addition of the CMC-7L® under conditions of low shear to form a gel of the paste having a viscosity in excess of 10MM poise and possessing a yield stress of greater than 1,000 Pa. This product is mixed and loaded into a cartridge of a length of 21.6 cm with a diameter of 5.1 cm. A plastic plunger plate is fitted into the open end of the tube. The other end of the tube narrows to an opening of 0.64 cm National Pipe Thread (NPT) at which a quick connect coupler is attached.

The cartridge is inserted into a cylinder sleeve the quick connect coupler of which protrudes at one end and which is closed on the other end to the closed gear box. The gear box has a 30.5 cm long linear actuator shaft which has 5.9 turns/cm. This shaft runs through the gear box with a 5.4 cm round plate attached to the end. This plate provides force against the plunger in the cartridge to put force on the crop protection product inside the cartridge. A 12 volt D.C. electric motor is connected by a coupler to the gear box to drive the gears turning the shaft to provide the forward movement of the actuator shaft engaging the plunger. Mechanical displacement results in a given volume of product dispensed for a given linear stroke. The rate at which materials forced through the solenoid and into the mixing chamber at a continuous or variable rate is dependent on the setting of a rheostat which controls the amount of electric current the motor receives thus determining the speed of its shaft rotation.

Those skilled in the art, having the benefit of the teachings of the present invention as hereinabove set forth, can effect numerous modifications thereto. These modifications are to be construed as being encompassed within the scope of the present invention as set forth in the appended Claims.

Claims

What is claimed is:

1. An apparatus for use in the direct injection of agricultural crop protection product comprising in combination:

(a) one or a plurality of container means for housing a highly viscous crop protection product composition such as a gelled-paste, comprising an optional replaceable cartridge having an outlet opening, and optionally having an inlet opening,

(b) pressure means associated with said container means for applying pressure to said crop protection product within said container means for dispensing of said crop protection product composition through said outlet opening in said container means,

(c) a mixing chamber, interconnected to said outlet opening in the container means, having a first inlet opening for receiving the crop protection product composition displaced from said opening of said container means, and a second inlet opening for permitting entry of a carrier medium for said crop protection product composition, and an outlet opening,

(d) shearing means positioned within said mixing chamber for dispersing said crop protection product composition into said carrier medium, and

(e) means for forcing a sprayable dispersion out of the outlet opening of said mixing chamber to be applied onto agricultural crops.

2. The apparatus of Claim 1 wherein the interconnection between said opening in said container means and said first opening of said mixing chamber includes means comprising: a manifold that receives flow of crop protection product compositions from the outlet opening of said container means and downstream from said manifold, a solenoid that controls the flow of said crop protection product compositions from said manifold to said first inlet opening of said mixing chamber, and a quick connect sealing means for connecting the interconnecting means to said opening of said container member.

3. The apparatus of Claim 2 wherein the crop protection product composition is an aqueous herbicidal gelled-paste sulfonylurea composition.

4. The apparatus of Claim 3 wherein the container means holds within it a replaceable cartridge, said cartridge housing said crop protection product compositions and said cartridge providing an opening fitted within the outlet opening in said container member, and being capable of being acted upon by said pressure means to provide dispensing of the crop protection product compositions through said outlet opening.

5. The apparatus of Claim 4 having support means for said container means and a plurality of cartridges for housing crop protection product compositions mounted on said container support means, and means for interconnecting each of the plurality to said manifold.

6. The apparatus of Claim 1 wherein the pressure means includes piston means located in the interior of the container member for applying said pressure.

7. The apparatus of Claim 6 wherein the container means houses a cartridge replaceably mounted therein and containing the crop protection product composition, and said piston means applies said pressure thereto.

8. The apparatus of Claim 1 wherein the shearing means comprises a stationary housing, said housing containing one or more exit slots, to allow the flow of the dispersed crop protection product composition, rotating blades positioned within said housing, said blades having close tolerance to said housing for applying said dispersion.

9. A method for treating agricultural crops comprising the steps of: providing a source of crop protection product composition in an extrudable form, forcing a measured amount of crop protection product composition from said source into a mixing zone, introducing a liquid carrier medium into said mixing zone, shearing the crop protection product composition together with the liquid carrier medium in said mixing zone sufficient to disperse said crop protection product composition within said liquid carrier medium in said mixing zone, and spraying the resulting mixture as it is formed onto the agricultural crop.

10. The method of Claim 9 wherein the source of the crop protection product composition is one or a plurality of replaceable cartridges containing the crop protection product composition, each having an outlet through which said extrudable product is dispensed.

11. A herbicide storage and transport system comprising in combination:

(a) a container member having at least one opening,

(b) crop protection product composition in extrudable form housed within said container member, and

(c) said container member being capable of reacting under pressure to extrude said crop protection product composition from said opening of said container for making said crop protection product composition available for application to agricultural crops.

12. The container member of Claim 11 wherein said crop protection product is an aqueous herbicidal gelled-paste sulfonylurea composition.

13. A container member of Claim 11 wherein said container member is cylindrical in shape with said opening at one end thereof, said container member also having a piston means positioned within said cylindrical shape, remote from said opening, being capable of displacement toward said opening to provide said pressure.

14. An aqueous herbicidal gelled-paste sulfonylurea composition comprising, in admixture, in weight percent based on total formulation weight:

1-85% of a stabilized sulfonylurea herbicide and optionally, at least one additional agricultural pesticide, 0.5-20% of one or a mixture of water soluble or water swellable synthetic, semisynthetic or biological polymer,

0-10% of dispersant, and an aqueous medium forming the balance; the sulfonylurea_^ polymer and aqueous medium in amounts effective to form a gelled-paste composition.

15. An aqueous herbicidal gelled-paste sulfonylurea composition comprising, in admixture, in weight percent based on total formulation weight: (a) 1-60% of a sulfonylurea herbicide and optionally, at least one additional agricultural pesticide,

(c) 0.5-20% of one or a mixture of water soluble or water swellable synthetic, semisynthetic or biological polymer,

(d) 0-10% of one or a mixture of dispersant, and

(e) an aqueous medium forming the balance; the sulfonylurea, polymer and aqueous medium in amounts effective to form a gelled-paste composition, provided that the sum of components (a) and (b) is no greater than 85%.

16. The composition of Claim 15 comprising:

(a) 20-40% of the sulfonylurea herbicide and optionally, at least one additional agricultural pesticide, (b) 10-25% of the agriculturally suitable salt of a carboxylic or inorganic acid,

(c) 0.5-2% of the polymer, and

(d) 1-2% of the dispersant.

17. The composition as in Claims 14, 15, or 16 wherein the water soluble or water swellable synthetic, semisynthetic or biological polymer is selected from the group consisting of alginates, alkali metal alginates, acrylic and methacrylic acids, acrylamides, ioto lambda carrageenans, cellulose gums and their derivatives, N-vinyl-2-pyrrolidinone, starches and their derivatives, and xanthan gums.

18. Compositions of Claim 16 wherein the sulfonylurea (s) is selected from the group consisting of chlorsulfuron; sulfometuron methyl; chlorimuron methyl; metsulfuron methyl; methyl 2— [ [ [ [ (4, 6— dimethoxy-2-pyrimidinyl) amino] carbonyl] amino] sulfonyl]- 6-(trifluoromethyl) -3-pyridinecarboxylate; ethamet- sulfuron methyl; triasulfuron; ethyl 5-[[[[(4,6- dimethoxy-2-pyrimidinyl)amino]carbonyl]amino] sulfonyl]- l-methyl-lϋf-pyrazole-4-carboxylate; _W-[ [ (4, 6-dimethoxy- 2-pyrimidinylamino] carbonyl] -3- (ethylsulfonyl) -2- pyridinesulfonamide; thifensulfuron methyl; tribenuron methyl; bensulfuron methyl; nicosulfuron; and methyl 2-[ [[[ [4,6-bis (difluoromethoxy-2-pyrimidinyl] amino]- carbonyl]amino] sulfonyl]benzoate.

19. A process for making a sulfonylurea herbicide gelled-paste composition comprising: combining stabilized sulfonylurea herbicide with an optional dispersing agent, optional additional herbicides, and a gelling agent, in aqueous medium in sufficient quantities to form a gelled-paste.

20. A process for making a sulfonylurea herbicide gelled-paste composition, comprising combining sulfonylurea herbicide, one or a mixture of agriculturally suitable salts of a carboxylic or inorganic acid, and optional additional herbicides in an aqueous medium to form a stable dispersion of the resultant sulfonylurea salt in the aqueous medium, then blending one or more gelling agents into said dispersion in sufficient amount to form a gelled-paste composition, which gelling agent is inert with respect to said herbicide(s) .

21. The process of Claim 20 wherein the gelled- paste composition is comprised of, in weight percent based on total formulation weight:

(a) a sulfonylurea herbicide and optionally, at least one additional agricultural pesticide, in the amount of 1-60% of active ingredient;

(c) one or a mixture of water soluble or water swellable synthetic, semisynthetic or biological polymers in the amount of 0.5-20%,

(d) 0-10% of a dispersant, and (e) an effective amount of an aqueous medium.

22. The process of Claim 21 wherein the gelled- paste is comprised of:

(a) 20-40% of a sulfonylurea herbicide and optionally, at least one additional agricultural pesticide,

(b) 10-25% of the agriculturally suitable salt of a carboxylic or inorganic acid,

(c) 0.5-2% of the polymer, and (d) 1-2% of the dispersant.