DRY, WATER-SOLUBLE POWDER, SUBSTITUTED HETEROCYCLIC ACID OR SUBSTITUTED PHENOL HERBICIDAL COMPOSITIONS, AND METHOD OF PREPARING SAME

Abstract: Dry, water-soluble powder, substituted heterocyclic acid, substituted phenol herbicidal compositions, combinations thereof, or in combination with phenoxy and/or benzoic acid herbicides, are prepared by grinding and dry blending the herbicide in acid form with a dry, particulate solubilization medium selected from the group consisting of diammonium phosphate, dipotassium phosphate, disodium phosphate, trisodium phosphate or tripotassium phosphate. At least about 1 mole of the medium is provided for each mole of active herbicidal agent in the initially dry blended mixture. The dry blended mixture may be packaged in suitable containers such as paper bags, and added directly to a quantity of water to form a solubilized herbicidal formulation containing from about 0.1 % to about 2-1/2 % of the active herbicide and which is suitable for direct application to vegetation to be controlled.

Description: DRY. WATER-SOLUBLE POWDER, SUBSTITUTED HETEROCYCLIC ACID OR SUBSTITUTED PHENOL HERBICIDAL COMPOSITIONS. AND METHOD OF PREPARING SAME Related Applications: This application is a continuation-in-part of Application Serial No. 07/745,866, filed August 16, 1991, now U.S. Letters Patent No. 5,221,319; Application Serial No. 07/911,757, filed July 10, 1992, which is now abandoned; and pending Application Serial No. 07/928,132, filed August 10, 1992. Background of the Invention 1. Field of the Invention This invention relates to water-soluble herbi- cidal compositions in dry powdered form which include herbicidally active agents selected from the group con¬ sisting of a herbicidally active substituted heterocyclic acid, a herbicidally active substituted heterocyclic acid combined with a solid herbicidally active substituted phenoxy acid, a herbicidally active substituted heterocy¬ clic acid combined with a solid herbicidally active substituted benzoic acid, a herbicidally active substi¬ tuted heterocyclic acid combined with a herbicidally active substituted phenoxy acid and a herbicidally active substituted benzoic acid, and a herbicidally active substituted phenol, each of which alone, or in combination with one another, are not readily soluble in water. 2. Description of the Prior Art Those herbicidal agents registered for use by commercial applicators are generally sold in concentrated form for economy of transport, and then diluted by the applicator either at a central distribution center, or less frequently at the point of use. The majority of effective herbicides and plant growth regulators are foliarly absorbed and therefore, to be effective, must be applied to the foliage of the target pest species. Other herbicides are root absorbed and the product must be applied in a manner as to be available to the roots of the target. This is commonly accomplished by spraying a dilute water solution, or dispersion of the desired pesticide on the vegetation to be treated. Most herbi¬ cides are therefore marketed as either (1) liquid or dry water-soluble formulations, (2) liquid, water emulsifiable formulations, or (3) solid or liquid water dispersible formulations. The concentrated formulations are diluted to the required effective concentration by the person doing the spray application. Thus, in order to obtain optimum effectiveness and to minimize agitation and other mechanical suspension requirements, water-soluble formula- tions are normally preferred. Because of the difficulties of manufacturing a dry, soluble form of herbicide, most dry formulations are simply dispersible forms of essentially insoluble active ingredients. Typical examples of formulations are (1) wettable powders, (2) water dispersible granules, or (3) dry flowables. Formulations of these types depend heavily on surfactants and grinding techniques to provide a dry formulation of active ingredients that can be temporarily dispersed or suspended in water for spray application. Even when a dispersion can initially be obtained in water, the time of full dispersion is usually limited, thus requiring stirring, agitation with air, or other mechan¬ ical mixing. Dispersions of this type present additional problems in that the material tends to clog spray nozzles and other distribution components, and require the user to prepare smaller than desired batches in order to minimize application problems. Because of the problems associated with at¬ tempting to prepare the dry powdered herbicide, suppliers have resorted in some instances to dissolution of the active ingredient in an organic solvent such as mineral spirits or the like. The concentrated formulation, containing suitable surfactants, is then diluted with water to form a dispersion that again usually necessitates some type of agitation to maintain the phases substan¬ tially homogeneous for a useful period of time. In instances where the herbicides are dissolved in a solvent for shipment as a concentrate, the solvent presents health and physical hazards to the manufacturer as well as the user, the solvents add to the overall cost of the product, and the solvent agent is oftentimes phyto- toxic to desirable plant species. The wettable powders and solvent dissolved herbicides are frequently packaged in plastic containers and disposal of these plastic packages is becoming in¬ creasingly difficult from an environmental standpoint. Substituted phenoxy and/or benzoic acid herbi¬ cides such as (2,4-dichlorophenoxy)acetic acid [2,4-D], 4- (2,4-dichlorophenoxy)butanoic acid [2,4-DB], (±)-2-(4- chloro-2-methylphenoxy)propanoic acid [MCPP] , (4-chloro-2- methylphenoxy)acetic acid [MCPA] , (±)-2-(2,4-dichloro- phenoxy)propanoic acid [dichlorprop] , 3,6-dichloro-2- methoxybenzoic acid [dicamba], 3-amino-2,5-dichlorobenzoic acid [chloramben] , and 5-[2-chloro-4-(trifluoromethyl)phe- noxy]-2-nitrobenzoic acid [acifluorfen] have long been used to control unwanted vegetation. These substituted phenoxy and/or benzoic acid herbicides are white crystalline solids with very low vapor pressures and low water solubilities. They are soluble only in alkaline solutions or polar organic solvents. Phenoxy and/or benzoic acid herbicides are available commercially as acid, ester, alkali metal, and amine salt formulations that can also be applied as mixtures with other herbicides. The alkali metal and especially the amine salt formulations are preferred because they are the most water-soluble and can be more readily applied as aqueous sprays. However, the esters must be applied either as emulsions in water, or as solutions in organic solvents such as oils. 2,4-D for example, is an insoluble crystalline material having a pK a of approximately 2.6. For ease of application, 2,4-D is normally converted to a water-soluble amine or mineral salt by the manufacturer and then dissolved by the appli- cator in a water carrier before use. However, water-soluble substituted phenoxy and/or benzoic acid salts exhibiting herbicidal activity are difficult to prepare in a dry state. Soluble salts such as potassium or sodium or dimethylamine must be first prepared in water or a solvent and then the solvent removed. This requires special equipment, is energy intensive, and frequently generates undesirable waste products. As a consequence, most dry forms of herbicide that are marketed are not of a soluble type but rather are merely dispersible forms of the essentially insoluble herbicide acid which are distributed as a wettable powder or a wettable, dispersible granule. Although both inor¬ ganic and organic salt forms are commercially available, the most common salt form is the dimethylamine salt of the substituted phenoxy or substituted benzoic acid herbicide. Typical formulations range from about 20% to 50% active ingredient concentrations in water or solvent solutions. Similarly, 3,6-dichloropicolinic acid as a monoethanolamine salt [clopyralid] , 3,5,6-trichloro-2- pyridyloxyacetic acid as a triethylamine salt [triclopyr] , 4-amino-3,5,6-trichloropicolinic acid as a potassium salt [picloram] , 3,7-dichloro-8-quinolinecarboxylic acid as a 50% wettable powder [quinclorac] and 3-isopropyl-lH-2,l,3- benzothiadiazin-4 (3H)-one 2,2-dioxide as a sodium salt [bentazon] have been used commercially as herbicidal compositions. Piclora has been combined with the amine salt of 2,4-D acid, clopyralid has been combined with the amine salt of 2,4-D acid, and triclopyr plus 2,4-D acid as an EC ester, have all been suggested and are in use as herbi¬ cidal agents. Wettable powders, water-soluble amine salts, oil soluble amine salts, and emulsifiable concentrates have also been provided of substituted phenolic herbicides including a 33.4% octanoic acid ester of 3,5-dibromo-4- hydroxybenzonitrile [bromoxynil], a 31.7% octanoic acid ester of bromoxynil plus 34% of isooctyl ester of 2- methyl-chlorophenoxyacetic acid, bromoxynil plus MCPA, and the octanoic acid ester of 3,5-diiodo-4-hydroxyben¬ zonitrile [ioxynil]. Various combinations of ioxynil and/or bromoxynil have been marketed in various foreign countries. The water solubility of a solid herbicidal phenol such as bromoxynil is no more than about 130 mg/L. The water solubility of ioxynil is no greater than about 50 mg/L. All of these herbicidal compositions suffer from the disadvantage that the acids either have to be convert- ed to water-soluble form by forming amine salts therefrom, or other equivalent treatment, before they may be used by an applicator. Summary of the Invention The present invention relates to a method of preparing dry, water-soluble powder, substituted hetero¬ cyclic acid or substituted phenol herbicidal compositions. The invention also concerns dry, water-soluble, powder, substituted heterocyclic acid or substituted phenol herbicidal compositions which may be dissolved in water at concentrations providing from at least about 0.1% to at least about 2-1/2% by weight of the active herbicide in the final herbicidal solution. A dry herbicidal product is preferred over a liquid concentrated herbicide for a number of reasons. Dry formulations are more stable to temperature variations encountered in storage and shipping. For example, freez¬ ing can destabilize liquid products interfering with the effectiveness of the herbicide. Similarly, high storage temperatures can lead to solvent losses when an organic solvent is used to dissolve the agent or cause hydrolysis when water is a solvent, thereby adversely affecting active ingredient concentrations. Dry herbicidal formulations are less dangerous than liquid products. Package leakage during handling is much less likely. If accidentally punctured, dry package leakage is much less severe and easier to clean up than a liquid product. Also, personnel protection is easier to accomplish with dry products because the material cannot as easily splash into the eyes or skin of the applicator. Spills of solvent containing formulations are potentially flammable, further militating against the use of solvents for dissolving the herbicide. The ease of packaging is significantly enhanced with dry products over liquid formulations and packaging flexibilities are greatly enhanced. Paper containers or wax treated packages can be used, as well as plastic containers. With liquids, specially treated plastic containers or glass containers are normally required. Paper or cardboard packages can be compressed and disposed of much easier than plastic, glass or metal containers. Transportation costs of dry products are po¬ tentially less expensive than is the case where a liquid carrier must also be transported. Although a number of concentrated liquid products having a fairly high active ingredient content are in commercial use, many formula- tions are sold in the 20-30% active ingredient range with the remainder of the product being water along with a small amount of dispersing agents or product appearance or handling enhancers. The dry, water-soluble powder, substituted heterocyclic acid or substituted phenol herbicidal com¬ positions of the subject invention are prepared by dry blending the herbicidal agent with a quantity of solid, substantially anhydrous diammonium phosphate (DAP) , dipotassium phosphate (DPP) , disodium phosphate (DSP) , trisodium phosphate (TSP) , tripotassium phosphate (TPP) , and mixtures thereof which serves as a solubilization medium for the herbicidal agent. A sufficient amount of the DAP, DPP, DSP, TSP or TPP solubilization medium is provided in the dry blended mixture in relationship to the quantity of herbicidal agent combined therewith to cause the dry blended mixture to substantially dissolve in water during preparation of a herbicidal solution which contains an adequate proportion of the herbicidal agent to provide from about 0.1% to about 2-1/2% by weight of the active herbicide in the herbicidal solution. A sufficient amount of the DAP, DPP, DSP, TSP or TPP solubilization medium is dry blended with the dry substituted heterocyclic acid or phenolic herbicidal agent, or a heterocyclic acid and phenolic herbicide with a phenoxy or benzoic acid herbicide to provide at least about 1 mole and to about 5 moles of the phosphate medium for each mole of active herbicidal agent in the dry blended mixture. The dry, water-soluble substituted heterocyclic acid or substituted phenol herbicides are easily manu¬ factured by dry blending the ingredients in powdered form. No unusual manufacturing techniques are required such as grinding to very fine sizes or classification procedures normally necessary to obtain a suitable dispersible product. Product raw material costs are comparable to widely used organic amine or salts of substituted hetero¬ cyclic or substituted phenol herbicide formulations currently being marketed. The raw materials are all commercially available and readily obtainable at com¬ petitive prices. Detailed Description of the Invention A quantity of a substantially solid herbicidal agent selected from the group consisting of a herbicidally active substituted heterocyclic acid, a herbicidally active substituted heterocyclic acid combined with a solid herbicidally active substituted phenoxy acid, a herbicid¬ ally active substituted heterocyclic acid combined with a solid herbicidally active substituted benzoic acid, a herbicidally active substituted heterocyclic acid combined with a herbicidally active substituted phenoxy acid and a herbicidally active substituted benzoic acid, a herbi¬ cidally active substituted phenol, a herbicidally active phenol combined with a herbicidally active substituted heterocyclic acid, a herbicidally active phenol combined with a herbicidally active substituted phenoxy acid, and a herbicidally active phenol combined with a herbicidally active substituted benzoic acid, each of which alone, or in combination with one another, are not readily soluble in water is added to an amount of a substantially solid solubilization medium for the herbicidal agent. The preferred solubilization agent is a quantity of solid, substantially anhydrous diammonium phosphate (DAP) , dipotassium phosphate (DPP) , disodium phosphate (DSP) , trisodium phosphate (TSP) , tripotassium phosphate (TPP) , and mixtures thereof which serves as a solubilization medium for the herbicidal agent. Examples of useful substituted heterocyclic herbicides include: 3,6-dichloropicolinic acid [clopyr- alid] ; 3,5,6-trichloro-2-pyridyloxyacetic acid [tri- clopyr] ; 4-amino-3,5,6-trichloropicolinic acid [picloram] ; 3,7-dichloro-8-quinolinecarboxylic acid [quinclorac] ; and 3-isopropyl-lH-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide [bentazon] . These single heterocyclic acids may be combined if desired in herbicidally active ratios with substituted phenoxy and/or benzoic acid herbicides which are in the acid form. Examples of useful phenoxy and/or benzoic acid herbicides are (2,4-dichlorophenoxy) acetic acid [2,4-D], 4-(2,4-dichlorophenoxy) butanoic acid [2,4- DB] , (+)-2-(4-chloro-2-methylphenoxy)propanoic acid [MCPP] , (4-chloro-2-methylphenoxy)acetic acid [MCPA] , (+)- 2-(2,4-dichlorophenoxy)propanoic acid [dichlorprop] , 3,6- dichloro-2-methoxy-benzoic acid [dicamba], 3-amino-2,5- dichlorobenzoic acid [chloramben] , and 5-[2-chloro-4- (trifluoromethyl)-phenoxy]-2-nitrobenzoic acid [acifluor- fen] . The herbicidal compositions therefore may comprise a single herbicidal substituted heterocyclic acid, the combination of a substituted heterocyclic acid with a solid herbicidal substituted benzoic acid, or the combination of a substituted heterocyclic acid with a solid herbicidal substituted phenoxy acid. None of these herbicides, or combinations thereof, are readily soluble in water. Examples of substituted phenolic herbicides useful in this invention include: 3,5-dibromo-4-hydroxy- benzonitrile [bromoxynil]; bromoxynil plus MCPA; and 3,5- diiodo-4-hydroxybenzonitrile [ioxynil]; and combinations of ioxynil and bromoxynil. Preferred formulations include at least about 25 weight percent of the active herbicidal acid, and in certain instances about 50 weight percent of the active herbicidal agent or combinations thereof. The herbicidal agent and the phosphate solubi- lization medium are dry blended to produce a substantially homogeneous mixture thereof. This dry blended mixture may be packaged in paper containers, or other suitable packag¬ es, without further processing such as pulverization, extended grinding, or critical classification. However, the particle size is preferably small enough to permit relatively rapid wetting when added to water. At least about l mole to about 5 moles of the solubilization medium is provided for each mole of active herbicidal agent in the dry blended mixture. EXAMPLE I The following ingredients were dry blended: Ingredients 1-5 of Example I were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 50% active herbicide powder prepared in accordance with Example I was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. EXAMPLE II The following ingredients were dry blended: The 50% active herbicide powder was prepared in accordance with Example I. Water solubility and oven stability were, likewise, similar. EXAMPLE III The following ingredients were dry blended: The 50% active herbicide powder was prepared in accordance with Example I. Water solubility and oven stability were, likewise, similar. EXAMPLE IV The following ingredients were dry blended: The 50% active herbicide powder was prepared in accordance with Example I. Water solubility and oven stability were, likewise, similar. EXAMPLE V The following ingredients were dry blended: Ingredients 1-5 of Example V were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 25% active herbicide powder prepared in accordance with Example V was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. EXAMPLE VI The following ingredients were dry blended: Ingredients 1-6 of Example VI were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 50% active herbicide powder prepared in accordance with Example VI was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. EXAMPLE VII The following ingredients were dry blended: Ingredients 1-6 of Example VII were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 50% active herbicide powder prepared in accordance with Example VII was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. EXAMPLE VIII The following ingredients were dry blended: Ingredients % Active Weight % Makeup HPLC Ingre¬ Reagents for (High dients Grinding Perfor¬ of 15 mance Grams - Liquid In Grams Chroma- tography Anal¬ ysis) 1. Picloram acid 10.00 10.53 1.58 10.08 Tech. Grade - (95%) 2. 2,4-D acid 40.00 41.24 6.19 40.27 Tech.Grade - (97%) 3. Sodium 1.00 0.15 napthalenesulfonate formaldehyde polymer (Lomar PW) 4. Sorbitan 1.00 0.15 tristearate (SPAN-65) 5. Spray dry 5.00 0.75 synthetic silica (Wessalon 50-S) 6. TSP - Trisodium 41.23 6.18 Phosphate - (Anhyd) TOTALS 100.00% 15.00 gms. The 50% active herbicide powder was prepared in accordance with Example VII. Water solubility and oven stability were, likewise, similar. EXAMPLE IX The following ingredients were dry blended: Ingredients % Active Weight % Makeup HPLC Ingre¬ Reagents for (High dients Grinding Perfor¬ of 15 * mance Grams - Liquid In Grams Chroma- tography Anal¬ ysis) 1. Clopyralid acid 8.00 8.42 1.26 8.09 Tech. Grade - (95%) 2. 2,4-D acid 42.00 43.30 6.50 41.81 Tech.Grade - (97%) 3. Sodium 1.00 0.15 napthalenesulfonate formaldehyde polymer (Lomar PW) 4. Sorbitan 1.00 0.15 tristearate (SPAN-65) 5. Spray dry 5.00 0.75 synthetic silica (Wessalon 50-S) 6. DSP - Disodium 41.28 6.19 Phosphate - (Anhyd) TOTALS 100.00% 15.00 gms. The 50% active herbicide powder was prepared in accordance with Example VII. Water solubility and oven stability were, likewise, similar. EXAMPLE X The following ingredients were dry blended: Ingredients % Active Weight % Makeup HPLC Ingre¬ Reagents for (High dients Grinding Perfor¬ r of 15 mance Grams - Liquid In Grams Chroma- tography Anal¬ ysis) 1. Quinclorac acid 13.33 14.18 2.13 14.35 Tech. Grade - (94%) 2. Dichlorprop acid 26.67 28.37 4.26 27.28 Tech.Grade - (94%) 3. Sodium 1.00 0.15 napthalenesulfonate formaldehyde polymer (Lomar PW) 4. Sorbitan 1.00 0.15 tristearate (SPAN-65) 5. Spray dry 5.00 0.75 synthetic silica (Wessalon 50-S) 6. TSP - Trisodium 50.45 7.56 Phosphate - (Anhyd) TOTALS 100.00% 15.00 gms. Ingredients 1-6 of Example X were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 50% active herbicide powder prepared in accordance with Example X was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. EXAMPLE XI The following ingredients were dry blended: Ingredients 1-7 of Example XI were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 50% active herbicide powder prepared in accordance with Example XI was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. EXAMPLE XII The following ingredients were dry blended: The 50% active herbicide powder was prepared in accordance with Example XI. Water solubility and oven stability were, likewise, similar. EXAMPLE XIII The following ingredients were dry blended: The 50% active herbicide powder was prepared in accordance with Example XI. Water solubility and oven stability were, likewise, similar. EXAMPLE XIV The following ingredients were dry blended: Ingredients % Active Weight % Makeup HPLC Ingre¬ Reagents for (High dients Grinding Perfor¬ of 15 mance Grams - Liquid In Grams Chroma- tography Anal¬ ysis) l. MCPA acid 33.34 35.09 5.26 33.47 Tech. Grade - (95%) 2. MCPP acid 13.33 14.03 2.10 13.13 Tech.Grade - (Dry, 95%) 3. Triclopyr Acid - 3.33 3.40 0.51 3.00 Tech. Grade - (98%) 4. Sodium 1.00 0.15 napthalenesulfonate formaldehyde polymer (Lomar PW) 5. Sorbitan 1.00 0.15 tristearate (SPAN-65) 6. Spray dry 5.00 0.75 synthetic silica (Wessalon 50-S) 7. TPP-Tripotassium 40.48 6.08 Phosphate - (Anhyd) TOTALS 100.00% 15.00 gms. Ingredients 1-7 of Example XIV were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 50% active herbicide powder prepared in accordance with Example XIV was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. EXAMPLE XV The following ingredients were dry blended: Ingredients 1-7 of Example XV were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 50% active herbicide powder prepared "in accordance with Example XV was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. EXAMPLE XVI The following ingredients were dry blended: Ingredients 1-5 of Example XVI were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 35% active herbicide powder prepared in accordance with Example XVI was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. EXAMPLE XVII The following ingredients were dry blended: The 30% active herbicide powder was prepared in accordance with Example XVI. Water solubility and oven stability were, likewise, similar. EXAMPLE XVIII The following ingredients were dry blended: Ingredients % Active Weight % Makeup HPLC Ingre¬ Reagents for (High dients Grinding Perfor¬ of 20.0 mance Grams - Liquid In Grams Chroma- tography Anal¬ ysis) 1. Bromoxynil 25.00 25.80 5.16 25.00 Tech. Grade-96.9% 2. Sodium nap- 1.00 0.20 thalenesulfonate formaldehyde polymer (Lomar PW) 3. Sorbitan tris- 1.00 0.20 tearate (SPAN-65) 4. Spray dry syn¬ 5.00 1.00 thetic silica (Wessalon 50-S) 5. TSP-Trisodium 67.20 13.44 phosphate (Anhyd) TOTALS 100.00% 20.00 gms. The 25% active herbicide powder was prepared in accordance with Example XVI. Water solubility and oven stability were, likewise, similar. EXAMPLE XIX The following ingredients were dry blended: Ingredients 1-5 of Example XIX were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 40% active herbicide powder prepared in accordance with Example XIX was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. EXAMPLE XX The following ingredients were dry blended: Ingredients % Active Weight % Makeup HPLC Ingre¬ Reagents for (High dients Grinding Perfor¬ of 15.0 mance Grams - Liquid In Grams Chroma- tography Anal¬ ysis) 1. Ioxynil 35.00 36.08 5.41 34.00 Tech. Grade-97% 2. Sodium nap- 1.00 0.15 thalenesulfonate formaldehyde polymer (Lomar PW) 3. Sorbitan tris- 1.00 0.15 tearate (SPAN-65) 4. Spray dry syn¬ 2.00 0.30 thetic silica (Wessalon 50-S) 5. DPP-Dipotassium 59.92 8.99 phosphate (Anhyd) TOTALS 100.00% 15.00 gms. The 35% active herbicide powder was prepared in accordance with Example XIX. Water solubility and oven stability were, likewise, similar. EXAMPLE XXI The following ingredients were dry blended: The 25% active herbicide powder was prepared in accordance with Example XIX. Water solubility and oven stability were, likewise, similar. The prepared aqueous sample containing 2.0 weight percent of the 25% to 50% active herbicide powder in all instances yielded a substantially clear solution within two minutes. It was not necessary to heat or agitate the product to maintain the ingredients in solu¬ tion while sitting on a shelf for several days at room temperature. Tests of the dry blended material dissolved in water yielded clear solutions at levels of 0.5%, 1%, 2%, and 4 weight percent. Weight percent in this respect means 1 gram of the active dry powder for each 99 illi- liters of tap water. Normal herbicide application con¬ centrations range from about 1/2 weight percent of the active acid to about 2% of the active acid. EXAMPLE XXII The following ingredients were dry blended: Ingredients 1-6 of Example XXII were ground to a fine, dry powder (averaging about 50 microns particle size) in a laboratory analytical mill. The mixture was transferred to a capped glass container. A 2 gm. sample of the 40% active herbicide powder prepared in accordance with Example XXII was added to a glass graduated cylinder which contained 98 ml. of city water. The stoppered cylinder was inverted several times over a period of 5 minutes. The 2 weight percent of herbicidal agent added to the water dissolved, with only a small quantity of silica remaining as a dispersion. After 96 hours in an oven at 50°C, a sample of the powder indicated no visible changes. It has been determined that the best results are obtained when an anhydrous DAP, DPP and DSP are utilized as the solubilization medium for the substituted phenoxy and/or benzoic acid herbicidal agent, with the preferred medium being DAP. In all cases, the anhydrous DAP, DPP, DSP, TSP or TPP solubilization medium should contain less than about 1% water by weight.

Claims: Claims : 1. A dry, water-soluble herbicide powder composition consisting essentially of: a dry blended admixture of a first quantity of dry, powder particles of a substantially solid herbicidal agent se¬ lected from the group consisting of a herbicidally active substituted hetero¬ cyclic acid, a herbicidally active substi- tuted heterocyclic acid combined with a solid herbicidally active substituted phenoxy acid, a herbicidally active substi¬ tuted heterocyclic acid combined with a solid herbicidally active substituted benzoic acid, a herbicidally active substi¬ tuted heterocyclic acid combined with a herbicidally active substituted phenoxy acid and a herbicidally active substituted benzoic acid, a herbicidally active sub- stituted phenol, a herbicidally active phenol combined with a herbicidally active substituted heterocyclic acid, a herbi¬ cidally active phenol combined with a herbicidally active substituted phenoxy acid, and a herbicidally active phenol combined with a herbicidally active sub¬ stituted benzoic acid, each of which alone. or in combination with one another, are not readily soluble in water, and a second quantity of dry, solid, powder particles selected from the group con- sisting of diammonium phosphate, dipo¬ tassium phosphate, disodium phosphate, tri¬ sodium phosphate, tripotassium phosphate, and mixtures thereof as a solubilization medium for the herbicidal agent, said first and second quantities of the herbi¬ cidal agent and the solubilization medium being the predominate constituents of the composition, there being at least about l mole of solubiliz- ation medium for each mole of herbicidal agent, said herbicidal agent and the solubilization medium having been dry blended in powdered form without changing the physical state of the particles to retain the discrete parti¬ culate character of each of said first and second quantities of said particles, and in the absence of chemical reaction between said herbicidal agent and said solubili- zation medium to form a relatively uniform dry mixture thereof. there being a sufficient quantity of the phos¬ phate medium in the dry blended mixture in relationship to the quantity of herbicidal agent combined therewith such that the dry blended powder mixture will dissolve in water during preparation of a herbicidal solution therefrom that contains an ade¬ quate proportion of the herbicidal agent to provide from about 0.1 to about 2-1/2% by weight of the active herbicidal agent in the herbicidal solution. 2. A herbicide as set forth in Claim 1 wherein said dry solubilization medium is diammonium phosphate. 3. A herbicide as set forth in Claim 1 wherein said dry solubilization medium is dipotassium phosphate. 4. A herbicide as set forth in Claim 1 wherein said dry solubilization medium is trisodium phosphate. 5. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is 3,6-dichloropicolinic acid. 6. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is 3,5,6-trichloro-2- pyridyloxyacetic acid. 7. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is 4-amino-3,5,6-tri- chloropicolinic acid. 8. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is 3,7-dichloro-8- quinolinecarboxylic acid. 9. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is 3-isopropyl-lH-2,l,3- benzothiadiazin-4(3H)-one 2,2-dioxide. 10. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is 3,5-dibromo-4-hy- droxybenzonitrile. 11. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is 3,5-dibromo-4-hy- droxybenzonitrile and 2-methyl-chlorophenoxyacetic acid. 12. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is 3,5-diiodo-4-hydroxy- benzonitrile. 13. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is 3,5-diiodo-4-hydroxy- benzonitrile and 3,5-dibromo-4-hydroxybenzonitrile. 14. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is a herbicide as set forth in any one of claims 5, 6, 7, 8, 9, 10, 11, 12 or 13 and further including a substituted phenoxy acid herbi¬ cide. 15. A herbicide as set forth in Claim 1 wherein said dry, solid, powder herbicide is a herbicide as set forth in any one of claims 5, 6, 7, 8, 9, 10, 11, 12 or 13 and further including a substituted benzoic acid herbi¬ cide. 16. A herbicide as set forth in Claim 14 wherein the dry blended admixture includes a mixture of substituted phenoxy acid and substituted benzoic acid herbicides. 17. A method of preparing a dry, water-soluble, herbicide powder composition consisting essentially of the steps of: providing a first quantity of dry, powder particles of a substantially solid herbicidal agent se¬ lected from the group consisting of a herbicid¬ ally active substituted heterocyclic acid, a herbicidally active substituted heterocyclic acid combined with a solid herbicidally active substituted phenoxy acid, a herbicidally active substituted heterocyclic acid combined with a solid herbicidally active substituted benzoic acid, a herbicidally active substituted hetero¬ cyclic acid combined with a herbicidally active substituted phenoxy acid and a herbicidally active substituted benzoic acid, and a herbicid¬ ally active substituted phenol, a herbicidally active phenol combined with a herbicidally active substituted heterocyclic acid, a herbi- cidally active phenol combined with a herbi¬ cidally active substituted phenoxy acid, and a herbicidally active phenol combined with a herbicidally active substituted benzoic acid, each of which alone, or in combination with one another, are not readily soluble in water, providing a second quantity of dry, solid powder particles consisting essentially of a solubili- zation medium for the herbicidal agent and selected from the group consisting of diammonium phosphate, dipotassium phosphate, disodium phosphate, trisodium phosphate and tripotassium phosphate, said first and second quantities of the herbicidal agent and the solubilization medium being the predominate constituents of the composition, there being at least 1 mole of solubilization medium for each mole of herbicidal agent; and dry blending the herbicidal agent and the solubiliza¬ tion medium in powdered form without changing the physical state of the particles to retain the discrete particulate character of each of said first and second quantities of said particles, and in the absence of chemical reaction between said herbicidal agent and said solubilization medium to produce a relatively uniform dry mixture thereof, a sufficient quantity of the phosphate solubilization medium being provided in the dry blended mixture in relationship to the quantity of herbicidal agent combined therewith to cause the powdered dry blended mixture to substantially dissolve in water during preparation by the applicator of a herbicidal solution which contains an adequate proportion of the herbicidal agent to provide from about 0.1% to about 2-1/2% by weight of the active herbicidal agent in the herbicidal solu¬ tion. 18. A method as set forth in Claim 17 wherein a sufficient quantity of the phosphate medium is present in the dry blended mixture to provide at least about 1 to about 5 mols of the medium for each mol of active herbi¬ cidal agent in the dry blended mixture. 19. A method as set forth in Claim 17 wherein is included the step of providing a mixture of said herbicidally active agents for dry blending with the phosphate medium. 20. A method as set forth in Claim 17 wherein said dry solubilization medium is diammonium phosphate. 21. A method as set forth in Claim 17 wherein said dry solubilization medium is dipotassium phosphate. 22. A method as set forth in Claim 17 wherein said dry solubilization medium is trisodium phosphate. 23. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is 3,6-dichloropicolinic acid. 24. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is 3,5,6-trichloro-2- pyridyloxyacetic acid. 25. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is 4-amino-3,5,6-tri- chloropicolinic acid. 26. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is 3,7-dichloro-8- quinolinecarboxylic acid. 27. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is 3-isopropyl-lH-2,l,3- benzothiadiazin-4(3H)-one 2,2-dioxide. 28. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is 3,5-dibromo-4-hy- droxybenzonitrile. 29. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is 3,5-dibromo-4-hy- droxybenzonitrile and 2-methyl-chlorophenoxyacetic acid. 30. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is 3,5-diiodo-4-hydroxy- benzonitrile. 31. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is 3,5-diiodo-4-hydroxy- benzonitrile and 3,5-dibromo-4-hydroxybenzonitrile. 32. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is a herbicide as set forth in any one of claims 23, 24, 25, 26, 27, 28, 29, 30 or 31 and further including a substituted phenoxy acid herbicide. 33. A method as set forth in Claim 17 wherein said dry, solid, powder herbicide is a herbicide as set forth in any one of claims 23, 24, 25, 26, 27, 28, 29, 30 or 31 and further including a substituted benzoic acid herbicide. 34. A method as set forth in Claim 32 wherein the dry blended admixture includes a mixture of sub¬ stituted phenoxy acid and substituted benzoic acid her¬ bicides. 35. A method as set forth in Claim 17 wherein is included the step of incorporating an anti-caking agent in the dry blended mixture. 36. A method of preparing a herbicide solution consisting essentially of the steps of: adding to a volume of water, a dry powdered herbicid¬ al composition containing a first quantity of dry, powder particles of a substantially solid herbicidal agent se¬ lected from the group consisting of a herbicidally active substituted hetero¬ cyclic acid, a herbicidally active substi- tuted heterocyclic acid combined with a solid herbicidally active substituted phenoxy acid, a herbicidally active substi¬ tuted heterocyclic acid combined with a solid herbicidally active substituted benzoic acid, a herbicidally active substi¬ tuted heterocyclic acid combined with a herbicidally active substituted phenoxy acid and a herbicidally active substituted benzoic acid, a herbicidally active subs- tituted phenol, a herbicidally active phenol combined with a herbicidally active substituted heterocyclic acid, a her¬ bicidally active phenol combined with a herbicidally active substituted phenoxy acid, and a herbicidally active phenol combined with a herbicidally active sub¬ stituted benzoic acid, each of which alone. or in combination with one another, are not readily soluble in water, and a second quantity of dry, solid, powder particles of a selected from the group consisting of diammonium phosphate, dipo¬ tassium phosphate, disodium phosphate, trisodium phosphate, tripotassium phos¬ phate, and mixtures thereof as a solubili¬ zation medium for the herbicidal agent, said first and second quantities of the herbi¬ cidal agent and the solubilization medium being the predominate constituents of the composition, there being at least about 1 mole of solubiliz- ation medium for each mole of herbicidal agent, said herbicidal agent and the solubilization medium having been subjected to only dry blended in powdered form without changing the physical state of the particles to retain the discrete particulate character of each of said first and second quantities of said particles, and in the absence of chemical reaction between said herbicidal agent and said solubilization medium, to form a relatively uniform dry mixture thereof; adding a sufficient quantity of the powdered dry blended admixture of the herbicidal agent and the phosphate solubilization medium to the volume of water to cause the powdered dry blended mixture dissolved in the water to provide from about 0.1% to about 2-1/2% by weight of the active herbicidal agent in the herbicidal solution; and agitating the water containing the herbicidal agent and the solubilization medium for a time period sufficient to effect substan¬ tial dissolution of the agent and the medium in the volume of water.

Inventors: CAHOY ROGER P, VAN HAFTON JOHN L, CAHOY, ROGER, P., VAN HAFTON, JOHN, L.
Applicants: PBI GORDON CORP, PBI-GORDON CORPORATION
Application year: 1993
Main classification: A01N25
IPC codes: A01N25, A01N37, A01N39, A01N43