Patent EA-001532-B1 (EA)
Title: Improved coated pesticidal matrices, a process for their preparation and compositions contaiing them
Inventor: SUN GUANGLIN
IPC: A01N25/04
Filed: 1998-07-08
Abstract: 1. A process for the preparation of a coated pesticidal matrix which process comprises: a) preparing an aqueous mixture comprising a pesticidal agent, a pH-dependent polymer and water, provided that the pH of the aqueous mixture is below the solubilization pH of the pH-dependent polymer; and b) drying the aqueous mixture of step (a) to produce the coated pesticidal matrix. 2. A process as claimed in claim 1 wherein one or more of a plasticizer, an activity enhancer, an ultraviolet protector and a glidant are included in the aqueous mixture. 3. A process as claimed in claim 1 or claim 2 wherein the pesticidal agent is selected from the group consisting of an insecticide, an acaricide, a nematocide, a fungicide and a herbicide and mixtures thereof. 4. A process as claimed in claim 3 wherein the insecticidal agent is a chemical or a biological insecticide. 5. A process as claimed in claim 4 wherein the chemical insecticide selected from the group consisting of chlorfenapyr, hydramethylnon, imidacloprid, 1-(6-chloro-3-pyridyl)-2-(nitromethylene)imidazolidine, fipronil, and 1-[1-(p-chlorophenyl)-2-fluoro-4-(4-fluoro-3-phenoxyphenyl)-2-butenyl]cyclopropane, (R,S)-(Z)-, and mixtures thereof. 6. A process as claimed claim 4 wherein the biological insecticide selected from the group consisting of V8vEGTDEL, V8vEGTDEL-AaIT, NPV Heliothis zea , Lymantria dispar NPV, AcMNPV E2, AcMNPV L1, AcMNPV V8, AcMNPV Px1, and Bacillus thuringiensis, and mixtures thereof. 7. A process as claimed in any one of claims 1 to 2 wherein the pH-dependent polymer is selected from the group consisting of an ethylacrylate and methacrylic acid copolymer, a methylmethacrylate and methacrylic acid copolymer, a methacrylic acid, methylacrylate and methylmethacrylate copolymer and mixtures thereof; the plasticizer is selected from the group consisting of a poly(ethyleneglycol), a poly(propyleneglycol), a citric acid ester, diethylphthalate, dibutylphthalate, castor oil, triacetin, and mixtures thereof; the ultraviolet protector is selected from the group consisting of carbon black, a benzophenone, a dye, titanium dioxide, and mixtures thereof; the activity enhancer is a stilbene compound; and the glidant is selected from the group consisting of talc, magnesium stearate, calcium stearate, calcium sulfate, and mixtures thereof. 8. A process as claimed in claim 7 wherein the pH-dependent polymer is selected from the group consisting of an ethylacrylate and methacrylic acid copolymer wherein the ratio of free carboxyl groups to esters groups is about 1:1, a methylmethacrylate and methacrylic acid copolymer wherein the ratio of free carboxyl groups to esters groups is from about 1:1 to about 1:2, a methacrylic acid, methylacrylate and methylmethacrylate copolymer wherein the ratio of the monomers is about 1:5:2 to 3:7:3, and mixtures thereof; the plasticizer is selected from the group consisting of triethylcitrate and a poly(ethyleneglycol) having an average molecular weight of about 1,000 to 10,000; and the stilbene compound is selected from the group consisting of blancophor BBH, calcofluor white M2R, phorwite AR, and mixtures thereof. 9. A process as claimed in any one of claims 1 or 2 wherein the pH-dependent polymer is a methylmethacrylate and methacrylic acid copolymer and said copolymer is partially solubilized with base. 10. A process as claimed in claim 9 wherein said base is selected from the group consisting of ammonium hydroxide, an alkali metal hydroxide, and an alkaline earth metal hydroxide. 11. A process as claimed in any one of claims 1 or 2 wherein in said drying step the aqueous mixture is spray dried. 12. A process as claimed in any one of claims 1 or 2 wherein the coated pesticidal matrix has a particle size less than about 20 (m. 13. A process as claimed in claim 12 wherein the coated pesticidal matrix has a particle size of about 2 (m to 10 (m. 14. A process as claimed in any one of claims 1 or 2 wherein the coated pesticidal matrix comprises about 1 to 50% by weight of the pesticidal agent, about 5 to 50% by weight of the pH-dependent polymer, 0 to about 25% by weight of the plasticizer, 0 to about 30% by weight of the ultraviolet protector, 0 to about 75% by weight of the activity enhancer, and 0 to about 15% by weight of the glidant. 15. A coated pesticidal matrix which comprises about 1 to 50% by weight of a pesticidal agent, about 5 to 50% by weight of a pH-dependent polymer, 0 to about 25% by weight of the plasticizer, 0 to about 30% by weight of the ultraviolet protector, 0 to about 75% by weight of the activity enhancer, and 0 to about 15% by weight of the glidant, characterised in that said polymer (1) comprises ester groups and free carboxylic groups, (2) is partially solubilized with base and (3) has pH of solubilization higher than pH of about 5,5. 16. A coated pesticidal matrix as claimed in claim 15 which comprises about 5 to 35% by weight of the pesticidal agent, about 10 to 45% by weight of the pH-dependent polymer, 0 to about 25% by weight of the plasticizer, 0 to about 20% by weight of the ultraviolet protector, 0 to about 45% by weight of the activity enhancer, and 0 to about 10% by weight of the glidant. 17. A coated pesticidal matrix as claimed in claim 15 wherein the pH-dependent polymer is selected from the group consisting of an ethylacrylate and methacrylic acid copolymer, a methylmethacrylate and methacrylic acid copolymer, a methacrylic acid, methylacrylate and methylmethacrylate copolymer, and mixtures thereof; the plasticizer is selected from the group consisting of a poly(ethyleneglycol), a poly(propyleneglycol), a citric acid ester, diethylphthalate, dibutylphthalate, castor oil, triacetin, and mixtures thereof; the ultraviolet protector is selected from the group consisting of carbon black, a benzophenone, a dye, titanium dioxide, and mixtures thereof; the activity enhancer is a stilbene derivative; and the glidant is selected from the group consisting of talc, magnesium stearate, calcium stearate, calcium sulfate, and mixtures thereof. 18. A coated pesticidal matrix as claimed in claim 17 wherein the pH-dependent polymer is selected from the group consisting of an ethylacrylate and methacrylic acid copolymer wherein the ratio of free carboxyl groups to esters groups is about 1:1, a methylmethacrylate and methacrylic acid copolymer wherein the ratio of free carboxyl groups to esters groups is from about 1:1 to about 1:2, a methacrylic acid, methylacrylate and methylmethacrylate copolymer wherein the ratio of monomers is about 1:5:2 to 3:7:3, and mixtures thereof; the plasticizer is selected from the group consisting of triethylcitrate and a poly(ethyleneglycol) having an average molecular weight of about 1,000 to 10,000; and the stilbene derivative is selected from the group consisting of blancophor BBH, calcofluor white M2R, phorwite AR, and mixtures thereof. 19. A coated pesticidal matrix as claimed in claim 15 wherein the pesticidal agent is a chemical insecticide or a biological insecticide. 20. A coated pesticidal matrix as claimed in claim 19 wherein the chemical insecticide is selected from the group consisting of chlorfenapyr, hydramethylnon, imidacloprid, 1-(6-chloro-3-pyridyl)-2-(nitromethylene)imidazolidine, fipronil, and 1-[1-(p-chlorophenyl)-2-fluoro-4-(4-fluoro-3-phenoxyphenyl)-2-butenyl]cyclopropane, (R,S)-(Z)-, and mixtures thereof. 21. A coated pesticidal matrix as claimed in claims 19 wherein the biological insecticide is selected from the group consisting of V8vEGTDEL, V8vEGTDEL-AaIT, NPV Heliothis zea , Lymantria dispar NPV, AcMNPV E2, AcMNPV L1, AcMNPV V8, AcMNPV Px1, and Bacillus thuringiensis, and mixtures thereof. 22. A coated pesticidal matrix as claimed in claims 15 having a particle size of less than about 20 (m. 23. A coated pesticidal matrix as claimed in claim 22 having a particle size of about 2 (m to 10 (m. 24. A wettable powder pesticidal composition which comprises about 0.5 to 40% by weight of a dispersing agent; about 1 to 10% by weight of a flow enhancing agent; about 10 to 70% by weight of a bulking agent; 0 to about 25% by weight of a wetting agent; 0 to about 35% by weight of a pH-modifying agent; and about 5 to 75% by weight of a coated pesticidal matrix as defined in claim 15. 25. A composition as claimed in claim 24 which comprises about 2 to 15% by weight of the dispersing agent; about 1 to 10% by weight of the flow enhancing agent; about 10 to 60% by weight of the bulking agent; 0 to about 15% by weight of the wetting agent; 0 to about 20% by weight of the pH-modifying agent; and about 5 to 75% by weight of the coated pesticidal matrix. 26. A composition as claimed in claim 24 wherein the pesticidal agent in the coated pesticidal matrix is a biological agent. 27. A composition as claimed in claim 26 which comprises about 2 to 10% by weight of the dispersing agent; about 1 to 10% by weight of the flow enhancing agent; about 20 to 50% by weight of the bulking agent; about 2 to 20% by weight of the pH-modifying agent; and about 15 to 60% by weight of the coated pesticidal matrix. 28. A composition as claimed in claim 24 wherein the pH-modifying agent is an solid organic acid. 29. A composition as claimed in claim 28 wherein the solid organic acid is citric acid. 30. A coated pesticidal matrix produced in accordance with method as claimed in claim 1. 31. A method for improving the residual control of a pest which comprises applying to the locus of the pest a pesticidally effective amount of a coated pesticidal matrix as defined in claim 15.