Stable pesticide dispersions

Abstract: Stable dispersions of certain pesticides in agricultural oil are provided. In particular, the dispersions include a particulate pesticide, agricultural oil, and an agricultural oil-soluble polymer, the polymer in some instances containing a copolymerized polar monomer. Also provided is a method for forming the stable dispersion.

Description: The present invention relates to a stable dispersion of a pesticide in an agricultural oil and a method for forming the dispersion. In particular the invention relates to a stable dispersion of a pesticide in an agricultural oil including: a pesticide having a particle size from 0.5-10 microns and selected from the group consisting of chlorinated nitrile, triazole, aralkyl triazole, triazole anilide, benzamide, alkyl benzamide, diphenyl ether, pyridine carboxylic acid, chloroaniline, organophosphate, phosphonic glycine salt, and mixtures thereof; an agricultural oil; and an agricultural oil-soluble polymer, the polymer having a weight average molecular weight from 3,000 to 120,000 and including 2.5-35 % by weight of a copolymerized polar monomer. And the invention is related to a stable dispersion of a pesticide in an agricultural oil comprising: ethylene bisdithiocarbamate having a particle size from 2-10 microns; an agricultural oil; and an agricultural oil-soluble polymer, said polymer having a weight average molecular weight from 3,000 to 90,000 and including 2.5-35% by weight of a copolymerized polar monomer. The invention is also related to a method for forming the stable dispersion. U. S. Patent No. 3,773,926 discloses a method of and composition for the treatment of plants, the compositions containing certain pesticides dispersed in a conventional agricultural oil employing an N-vinyl-2-pyrrolidinone (4-15%)/alkyl methacrylate (85-96%) copolymer dispersant. The dispersant polymer is disclosed to have a average molecular weight of from about 300,000 to about 1,000,000. U.S. Patent No. 3,131,119 discloses compositions containing salts of dithiocarbamic acids such as ethylenebisdithocarbamic acid and dimethyldithiocarbamic acid dispersed in oil using an organic solvent-soluble polymer which possesses a balance of hydrophilic and lipophilic groups. The lipophilic groups are supplied by hydrocarbon groups containing from 8-24 carbon atoms. The hydrophilic groups are supplied by multiple ether groups, carbonyl groups, carboxylic acid groups, carboxylic ester groups, amide groups, and amino groups. The organic solvent-soluble polymer is disclosed to have a molecular weight of about 100,000 to about 2,000,000. There remains the need for stable dispersion of a variety of pesticides. We have now surprisingly found that a variety of stable dispersions can be made using agricultural oil-soluble polymers having a lower molecular weight than previously disclosed. These compositions facilitate making and storing of the dispersions, also considered as concentrates, even in hot climates, for their effective use in agronomic applications. Accordingly, the present invention provides a stable dispersion of certain pesticides in an agricultural oil and a method for forming the stable dispersion. According to a first aspect of the present invention there is provided a stable dispersion of a pesticide in an agricultural oil comprising: a pesticide having a particle size from 0.5-10 microns and selected from the group consisting of chlorinated nitrile, triazole, aralkyl triazole, thiazole anilide, benzamide, alkyl benzamide, diphenyl ether, pyridine carboxylic acid, chloroaniline, organophosphate, phosphonic glycine salt, and mixtures thereof; an agricultural. oil, and an agricultural oil-soluble polymer, the polymer having a weight average molecular weight from 3,000 to 120,000 and including 2.5-35 % by weight of a copolymerized polar monomer According to a second aspect of the present invention there is provided stable dispersion of a pesticide in an agricultural oil comprising: ethylene bisdithiocarbamate having a particle size from 2-10 microns; an agricultural oil; and an agricultural oil-soluble polymer, the polymer having a weight average molecular weight from 3,000 to 90,000 and including 2.5-35% by weight of a copolymerized polar monomer. According to a third aspect of the present invention there is provided a method for forming a stable dispersion of a pesticide in an agricultural oil comprising admixing a pesticide selected from the group consisting of chlorinated nitrile, triazole, aralkyl triazole, thiazole anilide, benzamide, alkyl benzamide, diphenyl ether, pyridine carboxylic acid, chloroaniline, organophosphate, phosphonic glycine salt; an agricultural oil; and an agricultural oil-soluble polymer, the polymer having a weight average molecular weight from 3,000 to 120,000 and including 2.5-35 % by weight of a copolymerized polar monomer and mixing or shearing the admixture until the pesticide has a particle size from 0.5 to 10 microns. According to a fourth aspect of the present invention there is provided a method for forming a stable dispersion of a pesticide in an agricultural oil comprising admixing ethylene bisdithiocarbamate; an agricultural oil; and an agricultural oil-soluble polymer, said polymer having a weight average molecular weight from 3,000 to 90,000 and including 2.5-35 % by weight of a copolymerized polar monomer and mixing or shearing the admixture until the ethylene bisdithiocarbamate has a particle size from 2 to 10 microns. By "stable dispersion of a pestcide in an agricultural oil" herein is meant a dispersion which did not gel during the dispersion process, i.e., a dispersion which did not gel, for example, in the homogenizer, bead mill, or ball mill used to mix and shear the admixture of the pesticide, the polymer, and the agricultural oil. The stable dispersion is stable relative to a dispersion of the same pesticide prepared in like manner in the absence of the polymer. Prefered are dispersions which, in addition meet the inital properties below. More prefered are dispersions which further meet the following properties after 1-2 weeks holding at 54 C. Typical desired values of the measured properties are given. Initial Properties: appearance = no gelling viscosity = less than 2000 cps, most preferably less than 1000 cps After 1-2 weeks at 54 °C.: appearance = no gelling viscosity = less than 2000 cps, most preferably less than 1000 cps % separation = top clear liquid; separation less than 10%. sedimentation = sticky sediment on the bottom of jar; none. By "particle size" herein is meant the volume average particle diameter as measured, for example by a laser particle size instrument such as the Coulter LS-130 particle sizer. Pesticides herein include particulate agronomically effective fungicides, herbicides, and insecticides such as chlorinated nitrile, triazole, aralkyl triazole, thiazole anilide, benzamide, alkyl benzamide, diphenyl ether, pyridine carboxylic acid, chloroaniline, organophosphate, phosphonic glycine salt, and mixtures thereof. Also included are mixtures of the pesticides with other organic or inorganic agronomically active ingredients, for example, Dithane + Indar, Dithane + chlorothalonil, Dithane + cymoxanil, and Dithane + Copper Hydroxide. Examples of typical pesticides and their physical characteristics are presented in Table 1. Typical Pesticides used in this invention Trade Name Action Common Name Family Molecular Formula Melting Pt °C Sol. in H2O Bravo fungicide Chlorothalonil chlorinated nitrile C8CL4N2 250-251 0.6-1.2 ppm Dithane fungicide Mancozeb ethylene bisdithiocarbmate C4H6MNN2S4x Zny 192-204 6-20 ppm Systhane fungicide Myclobutanil triazole C15H17CIN4 63-68 142 ppm Indar fungicide Fenbuconazole aralkyl triazole C19H17CIN4 124-126 0.2 ppm Pulsar fungicide Thifluzamide C13H6Br2F6N2OS 178 1.6 ppm RH-7281 fungicide n/a alkyl benzamide C14H16O2NCl3 167 < 1 ppm Gallery herbicide Isoxaben amide C18H24N2O4 176-179 1-2 ppm Kerb herbicide Pronamide amide C12H11CL2NO 155-156 15 ppm Visor herbicide Thiazopyr pyridine carboxylic acid C16H17O2N2SF5 79-81 2.5 ppm Goal herbicide oxyfluorfen diphenyl ether C15H11ClF3NO4 85-90 0.1 ppm Stam herbicide propanil chloroaniline C9H9CI2NO 91 130 ppm Roundup herbicide glyphosate isopropyl ammonium salt phosphonic glycine salt C6H17N2O5PS >200 40-50% Imidan insecticide Phosmet organophosphate C11H12NO4PS2 72.0-72.7 25ppm Notes: Dithane, Systhane, Indar, Pulsar, Kerb, Visor, Goal, and Stam are trademarks of Rohm and Haas Company. Bravo is a trademark of ISK Biosciences, Gallery is a trademark of Dow Elanco. Imidan is a trademark of Gowan Co. Roundup is a trademark of Monsanto Co. RH-7281 is a product of Rohm and Haas Company. Typically the pesticides used in the stable dispersion and method for forming a stable dispersion of this invention were crystalline and had melting points greater than 50 °C., molecular weights greater than 200, low solubility in paraffinic solvents, typically less than 1%, and contained polar functional groups such as, for example, ester, carbonyl, hydroxy, and cyano. The agricultural oils used in the stable dispersions and method for forming a stable dispersion of this invention are oils suitable for agronomic application, typically of high purity, and generally composed of a single aliphatic chemical structure. They may be branched or linear in nature with typical carbon chain lengths of C 20 to C 26 . They are characterized by low odor, low solvency for organic and organo-metallic compounds, low phytotoxicity to biological species, and low volatility. Commercial examples agricultural oil are: Orchex 796, Orchex 692, Sunspray 7N, Sunspray 11N, Oleo Branco, Isopar M, Isopar V, 100 Neutral, and Exxsol D-130. Other oils such as mineral oil; crop oil such as, for example, vegetable oil, peanut oil, and cottonseed oil; or synthetic may be acceptable Typical physical characteristics of agricultural oils are: Specific Gravity at 60/60 °F 0.750 to 0.900 Flash Point >120°F Viscosity, SSU at 100°F 50 to 150 Unsulfonated residue >90% Distillation range 350°F to 450°F The agricultural oil-soluble polymers used in the stable dispersion and method for forming a stable dispersion of this invention typically are addition polymers formed from ethylenically unsaturated monomers. Prefered are copolymers of one or more monomers, the homopolymers of which are soluble in agricultural oils, and one or more polar monomers. More prefered are copolymers of one or more alkyl (meth)acrylates and one or more polar monomers. Examples of the alkyl (meth)acrylates [alkyl(meth)acrylates is used herein to mean alkyl methacrylate or alkyl acrylate where the alkyl group contains from 1 to 15 carbon atoms are methyl methacrylate (MMA), methyl acrylate, ethyl acrylate, propyl methacrylate, butyl methacrylate (BMA) and acrylate (BA), isobutyl methacrylate (IBMA), hexyl and cyclohexyl methacrylate, cyclohexyl acrylate 2-ethylhexyl acrylate (EHA), 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, isodecyl methacrylate (IDMA, based on branched (C 10 )alkyl isomer mixture), undecyl methacrylate, dodecyl methacrylate (also known as lauryl methacrylate), tridecyl methacrylate, tetradecyl methacrylate (also known as myristyl methacrylate), pentadecyl methacrylate and combinations thereof. Also useful are: dodecyl-pentadecyl methacrylate (DPMA), a mixture of linear and branched isomers of dodecyl, tridecyl, tetradecyl and pentadecyl methacrylates; and lauryl-myristyl methacrylate (LMA), a mixture of dodecyl and tetradecyl methacrylates. Examples of the alkyl (methacrylate) where the alkyl group contains from 16 to 24 carbon atoms are hexadecyl methacrylate, heptadecyl methacrylate, octadecyl methacrylate, nonadecyl methacrylate, eicosyl methacrylate, behenyl methacrylate(BehMA), and combinations thereof. Also useful are: cetyl-eicosyl methacrylate (CEMA), a mixture of hexadecyl, octadecyl and eicosyl methacrylate; and cetyl-stearyl methacrylate (SMA), a mixture of hexadecyl and octadecyl methacrylate. The alkyl methacrylate and alkyl acrylate monomers described above are generally prepared by standard esterification procedures using technical grades of long chain aliphatic alcohols, and these commercially available alcohols are mixtures of alcohols of varying chain lengths containing between 10 and 15 or 16 and 20 carbon atoms in the alkyl group. Consequently, for the purposes of this invention, alkyl methacrylate is intended to include not only the individual alkyl methacrylate product named, but also to include mixtures of the alkyl methacrylates with a predominant amount of the particular alkyl methacrylate named. The use of these commercially available alcohols to prepare acrylate and methacrylate esters results in the LMA, DPMA, SMA and CEMA monomer mixtures described above. The polar monomers may contain, for example hydroxy groups or Nitrogen-containing groups. The polar monomers preferably contain hydroxyl, carboxylic acid, basic nitrogen, or heterocyclic functionality. Examples of polar monomers are hydroxyalkyl(meth)acrylates such as hydroxypropyl methacrylate(HPMA), dialkylamino(C 1 -C 8 )alkyl (meth)acrylates such as dimethylaminoethyl methacrylate(DMAEMA) and dialkylamino(C 1 -C 8 )alkyl (meth)acrylamides such as dimethylaminopropyl methacrylamide(DMAPMAm), vinylpyridine, 2-methyl-5-vinylpyridine, 2-ethyl-5-vinylpyridine, 3-methyl-5-vinylpyridine, 2,3-dimethyl-5-vinylpyridine, 2-methyl-3-ethyl-5-vinylpyridine, methyl-substituted quinolines and isoquinolines, 1-vinylimidazole, 2-methyl-1-vinylimidazole(MVI), N-vinylcapro-lactam, N-vinylbutyrolactam and N-vinylpyrrolidone(NVP). To achieve oil solubility in a typical agricultural oil, the alkyl side chains of the acrylate/methacrylate monomers should average at least about C 7 -C 9 . However, typically as the amount of the polar monomer in the polymer increases, the average chain length of the alkyl side chains in the (meth)acrylate comonomers must be increased, in order to maintain oil solubility. Therefore, a polymer that contains greater than 10% by weight of copolymerized DMAPMAm (basic nitrogen) or copolymerized HPMA (free hydroxyl) typically requires a greater amount of alkyl side chains containing C 16 -C 18 alkyl rather than C 7 -C 9 alkyl. Prefered are copolymers of C 12 - C 20 methacrylates with 10-15 % by weight of DMAPMAm. More prefered are coplymers of stearyl methacrylate(SMA) with 10-20 % by weight of DMAPMAm. The weight average molecular weight of the polymer, typically from 3,000 to 120,000 or from 3,000 to 90,000, depending on the pesticide to be dispersed, may also have an effect on the viscosity of the formulation, with higher molecular weight leading to higher solution viscosity. Higher solution viscosity may decrease particle mobility and thus delay separation and settling. However, higher solution viscosity may hinder the flowability, transfer, and facile dilution of the pesticide dispersion. Prefered are weight average molecular weights of 15,000 to 90,000; more prefered are weight average molecular weights of 20,000 to 75,000. The polymers are typically made by addition polymerization in agricultural oil, preferably by gradual addition free-radical polymerization of the monomers. The polymers are typically prepared by mixing the monomers in the presence of a polymerization initiator, agricultural oil and, optionally, a chain transfer agent. The reaction may be run under agitation in an inert atmosphere at a temperature of from about 60 to 140 °C and more preferably from 115 to 125 °C. The reactions were typically run for about 4 to 10 hours or until the desired degree of polymerization hadbeen reached. As is recognized by those skilled in the art, the time and temperature of the reaction are dependent on the choice of initiator and can be varied accordingly. Polymers may be prepared by techniques known in the art to form graft polymers, block copolymers, star copolymers, or variable composition copolymers as well as random copolymers. Initiators useful for this polymerization are any of the well known free-radical-producing compounds such as peroxy, hydroperoxy and azo initiators including acetyl peroxide, benzoyl peroxide, lauroyl peroxide, t -butyl peroxyisobutyrate, caproyl peroxide, cumene hydroperoxide, 1,1-di(t-butylperoxy)-3,3,5-tri-methylcyclohexane, azobisisobutyronitrile, 2,2'azobis(2-methylbutane nitrile), and t-butyl peroctoate. The initiator concentration is normally between 0.025 and 1% by weight based on the total weight of the monomers and more preferably from 0.05 to 0.25%. Chain transfer agents may also be added to the polymerization reaction to control the molecular weight of the polymer. The prefered chain transfer agents are alkyl mercaptans such as lauryl (dodecyl) mercaptan, and the concentration of chain transfer agent used is from about 0.1 to about 10% by weight. The dispersion of a pesticide in agricultural oil was typically effected with pesticides which were either technical grade particulate pesticides("technicals") or formulated particulate pesticide compositions such as, for example, wettable powders and dispersible granules. The technical grade particulate pesticides ranged in active ingredient content from 80 to 98% by weight and were solid at room temperature. The wettable powders and dispersible granules ranged in active ingredient content from 45% by weight to 75% by weight and had typical compositions as follows: 45 to 75% by weight pesticide; 20 to 50% by weight carrier; 2 to 10% by weight dispersant; and 2 to 10% by weight surfactant. The wettable powders and dispersible granules typically had been milled to an average particle size in the range of 2 to 10 microns. The dispersions of this invention are typically applied in the field as dilutions into oil or oil/water/surfactant carriers. The spray tank mixtures may contain other formulated agronomic compositions such as, for example, surfactant adjuvants, emulsifiable concentrates, and wettable powders. Application may be made by ground or aerial spray equipment. EXAMPLE 1 Preparation of agricultural oil-soluble polymer Preparation of polymer 3. A 5 gallon reactor was fitted with a thermocouple, a temperature controller, a purge gas inlet, a water-cooled reflux condenser with purge gas outlet, a stirrer, and an addition tank. To the addition tank was charged 4911.59 grams of a monomer mixture of 4137.07 pbw stearyl methacrylate (96.5% purity), 704.52 pbw dimethylaminopropyl methacrylamide (100% purity), 40.00 pbw of a 50% solution of t-butyl peroctoate in mineral spirits (Lupersol PMS), 30.00 pbw dodecyl mercaptan. Sixty percent (2946.95 grams) of the monomer mixture in the addition tank and 736.74 grams of Orchex 796 oil were charged to the reactor which was then flushed with nitrogen for 30 minutes before applying heat to bring the contents of the reactor to 120°C. When the contents of the reactor reached 120°C, the balance of the monomer mixture in the addition tank was uniformly charged to the reactor over 90 minutes. At the end of the monomer mixture addition, the temperature in the reactor was lowered to 100°C and 1124.21 grams of a feed consisting of 314.21 pbw stearyl methacrylate, 60.00 pbw of a 50% solution of t-butyl peroctoate in mineral spirits (Lupersol PMS), and 750.00 pbw Orchex 796 oil was added uniformly over 120 minutes. Then the contents of the reactor were held 30 minutes at 100°C. At the end of the hold, the reaction temperature was raised to 120°C and 260.00 grams of a 10.00 pbw of a 50% solution of t-butyl peroctoate in mineral spirits (Lupersol PMS) and 250.00 pbw Orchex 796 oil was added to the reactor. The reaction was held at 120°C for 30 minutes. At the end of the 30 minute hold, 6000.00 grams of Orchex 796 oil was added to the batch. The batch was then held at ∼120°C for an additional 30 minute to create a homogeneous solution. The product so formed exhibited a polymer solids content of 32.65 wt%, a viscosity of 38 centistokes at 100°C. (210°F). Monomer conversion to polymer was calculated to be 98%. EXAMPLE 2 Preparation of agricultural oil-soluble polymer with grafted polar monomer. Preparation of Polymer No. 38 (Table 2). A 1 liter reactor was fitted with a thermocouple, a temperature controller, a purge gas inlet, a water-cooled reflux condenser with purge gas outlet, a stirrer, and an addition funnel. To the addition funnel was charged 259.39 grams of a monomer mixture of 230.77 parts by weight (pbw) stearyl methacrylate (97.5% purity), 12.50 pbw dimethylaminopropyl methacrylamide (100% purity), 1.50 pbw of a 50% solution of t-butyl peroctoate in mineral spirits (Lupersol PMS), 2.13 pbw dodecyl mercaptan. Thirty percent (77.82 grams) of the monomer mixture in the addition funnel was charged to the reactor which was then flushed with nitrogen for 30 minutes before applying heat to bring the contents of the reactor to 115°C. When the contents of the reactor reached 115°C, the balance of the monomer mixture in the addition funnel was uniformly charged to the reactor over 60 minutes. At the end of the monomer mixture addition, 38.50 grams of a chaser feed consisting of 1.00 pbw of a 50% solution of t-butyl peroctoate in mineral spirits (Lupersol PMS), and 37.50 pbw Orchex 796 oil was added uniformly over 90 minutes. Thirty minutes into the chaser feed, 12.50 grams of dimethylaminopropyl methacrylamide (100% purity) was charged to the reactor over 15 minutes as a separate feed. At the end of the chaser feed the contents of the reactor were held 60 minutes at 115°C. At the end of the 60 minute hold, 522.94 grams of Orchex 796 oil was added to the batch. The batch was then held at ∼115°C for an additional 30 minute to create a homogeneous solution. The product so formed exhibited a polymer solids content of 28.53 wt%, a viscosity of 22 cSt at 100 °C. (210°F.) Monomer conversion to polymer was calculated to be about 95%. EXAMPLE 3 Preparation of additional agricultural oil-soluble polymers Additional polymers were prepared according to the method of Example 1. Compositions and physical characteristics are presented in Table 2 below. Polymer Compositions and physical characteristics Polymer No. Composition Monomer Weight % Mol. wt. Solids 1 BehA/DMAPMAm 90/10 29,400 27.6 2 BehMA/ DMAPMAm 90/10 54,500 30.8 3 SMA/DMAPMAm 85/15 32,800 32.7 4 CEMA/IDMA/MMA 28/62/10 49,600 39.0 5 CEMA/IDMA/MMA/DMAPMAm 25.2/55.8/9/10 31,400 39.6 6 CEMA/IDMA/MMA/DMAPMAm 26.5/58.9/9.5/5 57,900 38.2 7 CEMA/IDMA/MMA/NVP 30/56/10/4 420,000 39.1 8 CEMA/LMA/DMAPMAm 4.5/91.5/4 45,900 9 CEMA/LMA/DMAPMAm 15/65/20 35,000 10 CEMA/LMA/IBMA/NVP 32.7/43.8/13.7/9.8 256,000 38.6 11 IDMA/DMAPMAm 85/15 19,700 29.6 12 IDMA/MMA 80/20 49,400 29.6 13 LMA 100 55,200 34.0 14 LMA/DMAPMAm 90/10 32,700 50.0 15 LMA/DMAPMAm 60/40 18,700 28.1 16 LMA/HPMA 90/10 64,800 31.5 17 LMA/IDMA 50/50 49,100 26.8 18 LMA/MMA 86.2/13.2 47,900 74.0 19 LMA/MMA 90/10 47,900 74.0 20 LMA/NVP 90/10 68,800 30.2 21 LMA/NVP 80/20 68,000 34.8 22 SMA/DMAEMA 95/5 49,200 29.3 23 SMA/DMAEMA 90/10 50,600 29.3 24 SMA/DMAEMA 80/20 52,300 29.1 25 SMA/DMAPMAm 95/5 44,400 29.4 26 SMA/DMAPMAm 95/5 77,700 28.7 27 SMA/DMAPMAm 90/10 35,300 22.7 28 SMA/DMAPMAm 90/10 88,200 28.0 29 SMA/DMAPMAm 90/10 94,000 29.3 30 SMA/DMAPMAm 80/20 20,600 29.6 31 SMA/DMAPMAm 80/20 25,600 27.9 32 SMA/DMAPMAm 70/30 20,000 28.9 33 SMA/DMAPMAm 60/40 17,600 30.2 34 SMA/DMAPMAm 85/15 18,600 28.8 35 SMA/DMAPMAm 85/15 20,800 30.3 36 SMA/DMAPMAm 85/15 22,000 30.0 37 SMA/DMAPMAm 85/15 27,600 27.9 38 SMA/DMAPMAm (5% grafted) 90/5/5 50,600 28.5 39 SMA/DMAPMAm (toluene) 90/10 27,200 51.4 40 SMA/IDMA 50/50 56,600 30.8 41 SMA/IDMA/MMA/HPMA 30.3/60.7/4/5 302,000 47.0 42 SMA/IDMA/MMA/NVP 30/56/10/4 237,000 47.5 43 SMA/MVI 90/10 73,900 29.4 44 BehMA/LMA/DMAPMAm 48/37/15 28,500 30.0 45 SMA/DMAPMAm 85/15 200,000 30.0 46 SMA/DMAPMAm 85/15 180,000 30.0 47 SMA/DMAPMAm 85/15 94,000 30.0 48 SMA/DMAPMAm 85/15 85,000 30.0 49 SMA/DMAPMAm 85/15 43,000 30.0 50 SMA/LMA/NVP 31.5/58.5/10 46,700 48.7 51 SMA/DMAPMAm 85/15 25,900 52 SMA/LMA/DMAPMAm 31.5/58.5/10 28,600 53 SMA/DMAPMAm 85/15 25,900 48.9 EXAMPLE 3. Preparation and exaluation of dispersions of pesticides. Compositions tested were typically: Pesticide solids 50 parts Polymer solids 0 to 5.0 parts Orchex 796 oil 42 to 50 parts All samples in Table 3 were prepared either at 0%, denoted as "none" for Polymer No. or at 5% by weight of polymer solids, except for experiments with Polymer No. 18 which was incorporated at 2% polymer solids by weight. Polymer was weighed into a tared stainless steel beaker and then Orchex 796 oil was added. The mixture was hand mixed with a spatula. Pesticide was weighed onto weighing paper and slowly added to the polymer/oil mixture with stirring. The mixture was hand mixed thoroughly with a spatula. Samples too viscous to homogenize directly and dry flowable compositions were pre-dispersed before homogenization. The sample was run until it was a well mixed and flowable mixture. All samples were homogenized using a a Silverson Model L4R homogenizer. The power dial was slowly increased to 2/3 power. Samples made from technicals and wettable powders were homogenized for 10 minutes. Dry flowables were homogenized until the granules appeared uniformly dispersed. Samples were also mixed during homogenization by gently swirling the sample container. Samples were evaluated as free flowing liquid (reported as "ok") or gelling (reported as "gel"). Bead (Eiger) milling was carried out for for those compositions starting with course particle size pesticides. The 50 ml Eiger mill (Model M50 from Eiger Machinery, Inc.) was loaded with 45 ml of 1 mm glass beads into the bead chamber. Cooling water was turned on. 2.54 cm (one inch) of sample was poured into the sample funnel. The mill was run with the sample mixture for one minute at 3500 rpm. The sample was discharged into a waste container and blown-out to push additional sample from the mill. The remaining sample was added to the sample funnel. The sample was milled for ten to thirty minutes at 3500 rpm. This treatment was believed to be sufficient to provide a dispersion of pesticide having a particle size of 0.5-10 microns. The sample was discharged immediately if there were signs of severe gelling (reported as "gel"). After milling the sample was discharged into a container. Evaluation for successful preparations was based upon examination initially and, if acceptable initially, after one week at 54 °C storage. Testing included: 1) Appearance - Samples were evaluated as free flowing liquid (reported as "ok") or gelling (reported as "gel"). 2) Viscosity - The sample was cooled to room temperature. The sample was stirred with a metal spatula for 40 seconds. Viscosity was measured using Brookfield Viscometer LVT, number 3 spindle, and speed setting knob at 60/3. The average of two readings was reported. 3) Storage stability - After one week of storage at 54°C, the sample was removed from the oven and allowed to cool to room temperature. The sample was examined for gelling and separation. If sample separated, the ratio of the top layer to the bottom layer was recorded as percentage separation. A metal spatula was inserted into material and the bottom of the container was probed. The spatula was examined for adhered sticky sediment, and recorded if found. The viscosity of samples that were not badly gelled or separated was measured as above and recorded. Properties examined: Initially: appearance - mixture either liquid or gel; desire no gelling viscosity - desire less than 2000 cps, preferably less than 1000 cps After storage for 2 weeks at 54 °C: appearance - mixture either liquid or gel; desire no gelling viscosity - desire less than 2000 cps, preferably less than 1000 cps % separation - top clear liquid separation; desire less than 10%. sedimentation - sticky sediment on the bottom of jar; desire none. Results were classified by the following key words, which are listed in order of decreasing performance: ok = Liquid, < 1000 cps viscosity, <10% sep, no sediment sep = Separation greater than 10% after storage. visc1 = Viscosity above 1000 cps before storage. visc2 = Viscosity above 1000 cps after storage. sed = Sedimentation severe enough to affect viscosity. movement to pass) bead = gels during or after bead milling (sample must have fluid movement to pass) gel = Immediately or after homogenization (sample must have fluid pass) Oil suspensions that exhibit gelling in the homogenizer or bead mill are not acceptable. All others are acceptable, but in varying degrees of quality. Testing of Polymer Dispersions Sample ID Active Ingredient Polymer No. Homogenizer Bead Mill Appearance Viscosity Appearance Visc. % Sep Sed Comp Da Dithane M 45-T none gel n/a n/a n/a n/a n/a n/a n/a D-1 Dithane M 45-T 4 ok ok ok 330 ok 220 3 none D-2 Dithane M 45-T 18 ok ok ok 270 ok 300 2 none Comp Db Dithane M 45-T 12 ok gel gel n/a n/a n/a n/a n/a Comp Dc Dithane M 45-T 15 gel n/a n/a n/a n/a n/a n/a n/a D-3 Dithane M 45-T 32 ok ok ok 380 ok 350 1 none D-4 Dithane M 45-T 9 ok ok ok 320 sep n/a 5 yes D-5 Dithane M 45-T 31 ok ok ok 240 ok 320 2 none D-6 Dithane M 45-T 36 ok ok ok 310 ok 450 2 none D-7 Dithane M 45-T 37 ok ok ok 350 ok 300 2 none D-8 Dithane M 45-T 29 ok ok ok 810 ok 730 1 none D-9 Dithane M 45-T 28 ok ok ok 790 ok 1300 1 none D-10 Dithane M 45-T 44 ok ok ok 130 ok n/a 0 yes Comp Dd Dithane M 45-T 45 ok ok ok 690 gel n/a 2 no Comp De Dithane M 45-T 46 ok ok ok 540 ok 1880 2 no D-13 Dithane M 45-T 47 ok ok ok 510 ok 860 5 no D-14 Dithane M 45-T 48 ok ok ok 410 ok 630 2 slight D-15 Dithane M 45-T 49 ok ok ok 300 ok 240 2 slight D-16 Dithane M 45-T 38 ok ok ok 230 ok 230 3 none D-17 Dithane M 45-T 21 ok ok ok 620 ok 845 2 none D-18 Dithane M 45-T 20 ok ok ok 370 ok 190 2 none D-19 Dithane M 45-T 23 ok ok ok 260 ok 250 2 none D-20 Dithane M 45-T 41 ok ok ok 590 ok 440 1 none D-21 Dithane M 45-T 43 ok gel gel n/a n/a n/a n/a n/a Comp Ga Gallery75df none gel n/a gel n/a n/a n/a n/a n/a Comp Gb Gallery75df 18 ok n/a ok 780 gel n/a 0 none G-1 Gallery75df 36 ok n/a ok 430 gel n/a 50 yes G-2 Gallery75df 28 ok n/a ok 540 ok 720 2 none G-3 Gallery75df 25 ok n/a ok 390 ok 1250 1 none Comp la Imidan70wp none gel n/a gel n/a n/a n/a n/a n/a Comp Ib Imidan70wp 18 gel n/a gel n/a n/a n/a n/a n/a Comp Ic Imidan70wp 12 gel n/a gel n/a n/a n/a n/a n/a I-1 Imidan70wp 15 ok n/a ok 1200 gel n/a 1 none I-2 Imidan70wp 36 ok n/a ok 300 sep n/a 25 yes I-3 Imidan70wp 28 ok n/a ok 500 sep 900 5 none I-4 Imidan70wp 25 ok n/a ok 340 sep 470 2 none I-5 Imidan70wp 23 ok n/a ok 290 sep 350 5 none I-6 Imidan70wp 43 ok n/a ok 500 sep n/a 33 yes Comp Ka Kerb50w none gel n/a n/a n/a n/a n/a n/a n/a Comp Kb Kerb50w 4 gel n/a gel n/a n/a n/a n/a n/a Comp Kc Kerb50w 18 gel n/a gel n/a n/a n/a n/a n/a Comp Kd Kerb50w 12 gel n/a gel n/a n/a n/a n/a n/a Comp Ke Kerb50w 15 ok n/a ok 630 sep 650 7 none K-1 Kerb50w 36 ok n/a ok 240 sep 320 10 none K-2 Kerb50w 28 ok n/a ok 260 sep 340 7 none K-3 Kerb50w 25 ok n/a ok 420 ok 630 0 none K-4 Kerb50w 23 ok n/a ok 1040 ok 1600 0 none K-5 Kerb50w 43 ok n/a ok 580 ok 820 0 none Comp IWPa IndarWP75 none gel n/a n/a n/a n/a n/a n/a n/a Comp IWPb IndarWP75 12 gel n/a n/a n/a n/a n/a n/a n/a Comp IWPc IndarWP75 18 gel n/a n/a n/a n/a n/a n/a n/a IWP-1 IndarWP75 23 ok n/a ok 510 gel n/a none none IWP-2 IndarWP75 31 ok n/a ok 520 ok 900 2 none IWP-3 IndarWP75 36 ok n/a ok 450 ok 980 2 none IWPA IndarWP75 43 ok n/a ok 690 gel n/a n/a n/a Comp la Indar tech none ok gel gel n/a n/a n/a n/a n/a Comp Ib Indar tech 40 ok gel gel n/a n/a n/a n/a n/a Comp Ic Indar tech 12 ok gel gel n/a n/a n/a n/a n/a Comp Id Indar tech 15 ok gel gel n/a n/a n/a n/a n/a I-1 Indar tech 31 ok ok ok 520 ok 670 none none I-2 Indar tech 30 ok ok ok 620 ok 620 none none I-3 Indar tech 44 ok ok ok 650 ok 1100 0 none Comp le Indar tech 45 ok ok ok 780 ok 520 0 none Comp If Indar tech 46 ok ok ok 760 ok 620 0 none I-4 Indar tech 47 ok ok ok 600 ok 500 0 none I-5 Indar tech 48 ok ok ok 550 ok 380 0 none I-6 Indar tech 49 ok ok ok 480 ok 360 0 none I-7 Indar tech 36 ok ok ok 350 ok 515 none none I-8 Indar tech 11 ok gel gel n/a n/a n/a n/a n/a I-9 Indar tech 1 ok gel gel n/a n/a n/a n/a n/a I-10 Indar tech 2 ok ok ok 1500 gel n/a none none I-11 Indar tech 5 ok gel gel n/a n/a n/a n/a n/a I-12 Indar tech 27 ok ok ok 650 gel n/a none none I-13 Indar tech 29 ok ok ok 680 ok 620 none none I-14 Indar tech 28 ok ok ok 600 ok 490 none none I-15 Indar tech 39 ok ok ok 790 gel n/a none none I-16 Indar tech 14 ok ok ok 1520 gel n/a none none I-17 Indar tech 26 ok ok ok 960 gel n/a none none I-18 Indar tech 38 ok gel gel n/a n/a n/a n/a n/a I-19 Indar tech 20 ok ok gel n/a n/a n/a n/a n/a I-20 Indar tech 24 ok ok ok 1680 gel n/a none none I-21 Indar tech 43 ok ok ok 580 ok 800 none none Comp SWPa Systhane 40wp 4 gel n/a gel n/a n/a n/a n/a n/a Comp SWPb Systhane 40wp 18 gel n/a n/a n/a n/a n/a n/a n/a Comp SWPc Systhane 40wp 12 gel n/a n/a n/a n/a n/a n/a n/a SWP-1 Systhane 40wp 31 ok n/a ok 470 ok 370 3% none SWP-2 Systhane 40wp 1 gel n/a gel n/a n/a n/a n/a n/a SWP-3 Systhane 40wp 36 ok n/a ok 530 ok 390 3 none SWP-4 Systhane 40wp 29 ok n/a ok 1010 ok 1700 none none SWP-5 Systhane 40wp 44 ok n/a ok 390 ok 380 0 none Comp SWPd Systhane 40wp 45 ok n/a ok 980 ok 1670 0 none Comp SWPe Systhane 40wp 46 ok n/a ok 840 ok 1700 0 none SWP-6 Systhane 40wp 47 ok n/a ok 550 ok 1460 0 none SWP-7 Systhane 40wp 48 ok n/a ok 600 ok n/a n/a n/a SWP-8 Systhane 40wp 49 ok n/a ok 220 sep 300 20 none SWP-9 Systhane 40wp 25 ok n/a ok 630 ok 690 0 none SWP-9 Systhane 40wp 23 gel n/a n/a n/a n/a n/a n/a n/a SWP-10 Systhane 40wp 7 gel n/a gel n/a n/a n/a n/a n/a SWP-11 Systhane 40wp 43 ok n/a ok 790 ok 790 none none Comp TCa T-chlorothalonil none ok gel gel n/a n/a n/a n/a n/a Comp TCb T-chlorothalonil 4 ok gel gel n/a n/a n/a n/a n/a Comp TCc T-chlorothalonil 18 ok gel gel n/a n/a n/a n/a n/a Comp TCd T-chlorothalonil 12 ok gel gel n/a n/a n/a n/a n/a Comp TCe T-chlorothalonil 15 ok gel gel n/a n/a n/a n/a n/a TC-1 T-chlorothalonil 31 ok ok ok 160 sep n/a 0 yes TC-2 T-chlorothalonil 36 ok ok ok 160 sep n/a 0 yes TC-3 T-chlorothalonil 28 ok ok ok 250 sep n/a 0 yes TC-4 T-chlorothalonil 25 ok ok ok 240 ok 170 0 none TC-5 T-chlorothalonil 23 ok ok ok 340 ok 180 0 none TC-6 T-chlorothalonil 20 ok gel gel n/a n/a n/a n/a n/a TC-7 T-chlorothalonil 43 ok ok ok 80 gel n/a 0 none Comp Ta Thifluzamide none gel n/a gel n/a n/a n/a n/a n/a Comp Tb Thifluzamide 18 gel n/a gel n/a n/a n/a n/a n/a Comp Tc Thifluzamide 4 gel n/a gel n/a n/a n/a n/a n/a Comp Td Thifluzamide 12 gel n/a gel n/a n/a n/a n/a n/a Comp Te Thifluzamide 15 gel n/a gel n/a n/a n/a n/a n/a T-1 Thifluzamide 36 ok n/a ok 560 ok 985 1 none T-2 Thifluzamide 28 ok n/a ok 820 ok 1530 2 none T-3 Thifluzamide 25 ok n/a ok 790 ok 1150 2 none T-4 Thifluzamide 22 gel n/a gel n/a n/a n/a n/a n/a T-5 Thifluzamide 43 gel n/a gel n/a n/a n/a n/a n/a Comp Va Visor50w none gel n/a n/a n/a n/a n/a n/a n/a Comp Vb Visor50w 4 gel n/a n/a n/a n/a n/a n/a n/a Comp Vc Visor50w 18 gel n/a n/a n/a n/a n/a n/a n/a Comp Vd Visor50w 12 gel n/a n/a n/a n/a n/a n/a n/a Comp Ve Visor50w 15 gel n/a n/a n/a n/a n/a n/a n/a V-1 Visor50w 44 ok n/a ok 400 ok n/a 2 none Comp Vf Visor50w 45 ok n/a ok 860 gel n/a 1 none Comp Vg Visor50w 46 ok n/a ok 820 gel n/a 1 none V-2 Visor50w 47 ok n/a ok 600 gel n/a 1 none V-3 Visor50w 48 ok n/a ok 580 gel n/a 1 n/a V-4 Visor50w 49 ok n/a ok 1400 gel n/a 1 none V-5 Visor50w 36 ok n/a ok 580 ok 480 4 none V-6 Visor50w 28 ok n/a ok 570 ok 1100 2 none V-7 Visor50w 25 ok n/a ok 380 ok 660 0 none V-8 Visor50w 23 gel n/a n/a n/a n/a n/a n/a n/a V-9 Visor50w 43 gel n/a n/a n/a n/a n/a n/a n/a EXAMPLE 4. Preparation and evaluation of Goal (oxyfluorfen) oil dispersion 10% Polymer No. 50, 42% Goal 95 Technical, 43% 100 neutral oil, and 5% Latron CS-7 (adjuvant-surfactant; from Rohm and Haas Company) were homogenized together and then Eiger milled for 30 minutes. A satisfactory dispersion was produced. EXAMPLE 5: Preparation and evaluation of Goal/Glyphosate oil dispersion A mixture of 3.35% of Goal (oil flowable), 53.65% Glyphosate, 3.5% Polymer No. 51, 34.5% 100N neutral oil and 5% Triton X-114 were weighed into a ceramic jar. Quarter inch ceramic milling media was then added to the ceramic jar. The ceramic jar was placed on a roller and ball milled at 40 rpm for seventy hours. A satisfactory dispersion was produced. EXAMPLE 6. Preparation and evaluation of RH 7281 dispersion A mixture of 40% RH7281 benzamide, 3% Polymer No. 52, and 57% 100 N neutral oil were blended together, homogenized and Eiger milled according to the method of Example 3. A sample of the composition was stored in the laboratory at ambient temperature for seven months and appeared uniform with no separation. EXAMPLE 7. Preparation and evaluation of glyphosate dispersion A sample of glyphosate isopropyl ammonium salt was jet air milled to a particle size of 2-5 microns. A sample of 45.0 g the glyphosate isopropyl ammonium salt, 3.5 g. Polymer No. 53, and 47.85 Chevron 100 neutral oil were mixed in a beaker and homogenized in a beaker for 2-3 minutes using a Ultra-Turrax T25 homogenizer (made by Janke & Kunke). The product dispersion was acceptable; it was a free-flowing off-white fluid with no gelling. Viscosity was 303 cps at 25 °C (Brookfield viscometer, Spindle #1, 100 rpm). EXAMPLE 8. Preparation and evaluation of Dithane/cymoxanil dispersion A mixture of 50 parts of Dithane technical grade (86% a.i.), 6 parts of cymoxanil (95% a.i.), and 5 parts Polymer sample No. 36 made up to 100 parts with Orchex 796 oil was prepared. The mixture was homogenized for 5 minutes and bead milled for 5 minutes. A uniform dispersion with a viscosity of 2000 cps resulted. After one week at 40 °C the dispersion had a viscosity of 2500 cps. EXAMPLE 9. Preparation and evaluation of Dithane/copper hydroxide dispersion A mixture of 30 parts of Dithane technical grade (86% a.i.), 28 parts of copper hydroxide (65% copper) and 5 parts Polymer sample No. 36 made up to 100 parts with Orchex 796 oil was prepared. The mixture was homogenized for 5 minutes and bead milled for 5 minutes. A uniform dispersion with a viscosity of 1500 cps resulted. After one week at 40 °C the dispersion had a viscosity of 1700 cps.

Claims: A stable dispersion of a pesticide in an agricultural oil comprising: a pesticide having a particle size from 0.5-10 microns and selected from the group consisting of chlorinated nitrile, triazole, aralkyl triazole, thiazole anilide, benzamide, alkyl benzamide, diphenyl ether, pyridine carboxylic acid, chloroaniline, organophosphate, phosphonic glycine salt, and mixtures thereof; an agricultural oil; and an agricultural oil-soluble polymer, said polymer having a weight average molecular weight from 3,000 to 120,000 and comprising 2.5-35 % by weight of a copolymerized polar monomer. The dispersion of claim 1 wherein said pesticide is selected from the group consisting of chlorothalonil, myclobutanil, fenbuconazole, thifluzamide, isoxaben, propyzamide, thiazopyr, oxyfluorfen, glyphosate isopropyl ammonium salt, propanil, phosmet, and mixtures thereof. The dispersion of claim 1 or claim 2 wherein said polymer has a weight average molecular weight from 20,000 to 75,000. The dispersion of claim 1 or claim 2 or claim 3 wherein said polymer comprises 10-20% by weight of said copolymerized polar monomer. The dispersion of claim 1 or claim 2 or claim 3 wherein said polymer is a copolymer comprising 85-90% by weight C 12 -C 20 methacrylate and 10-15% dimethylaminopropyl methacrylamide. A stable dispersion of a pesticide in an agricultural oil comprising: ethylene bisdithiocarbamate having a particle size from 2-10 microns; an agricultural oil; and an agricultural oil-soluble polymer, said polymer having a weight average molecular weight from 3,000 to 90,000 and comprising 2.5-35 % by weight of a copolymerized polar monomer. A method for forming a stable dispersion of a pesticide in an agricultural oil comprising admixing a pesticide selected from the group consisting of chlorinated nitrile, triazole, aralkyl triazole, thiazole anilide, benzamide, alkyl benzamide, diphenyl ether, pyridine carboxylic acid, chloroaniline, organophosphate, phosphonic glycine salt; an agricultural oil; and an agricultural oil-soluble polymer, said polymer having a weight average molecular weight from 3,000 to 120,000 and comprising 2.5-35 % by weight of a copolymerized polar monomer and mixing or shearing said admixture until said pesticide has a particle size from 0.5 to 10 microns. A method for forming a stable dispersion of a pesticide in an agricultural oil comprising admixing ethylene bisdithiocarbamate; an agricultural oil; and an agricultural oil-soluble polymer, said polymer having a weight average molecular weight from 3,000 to 90,000 and comprising 2.5-35 % by weight of a copolymerized polar monomer and mixing or shearing said admixture until said ethylene bisdithiocarbamate has a particle size from 2 to 10 microns.

Inventors: GORE ROBERT HOWARD, HOUGHTON RICHARD DAVID, MACHLEDER WARREN HARVEY, MATHIS WILLIAM DEAN, NGUYEN LUONG TU, STEVENS BRIDGET MARIE, SUN YAN, GORE, ROBERT HOWARD, HOUGHTON, RICHARD DAVID, MACHLEDER, WARREN HARVEY, MATHIS, WILLIAM DEAN, NGUYEN, LUONG TU, STEVENS, BRIDGET MARIE, SUN, YAN
Applicants: ROHM & HAAS, ROHM AND HAAS COMPANY
Application year: 1998
Main classification: A01N25
IPC codes: A01N37, A01N43, A01N25, A01N57, A01N33