WO1997039626A1

WO1997039626A1 - Pesticides trapped in emulsifiable granules

Info

Publication number: WO1997039626A1
Application number: PCT/US1997/005631
Authority: WO
Inventors: Patrick Dejean De La Batie; Dominique Bilger
Original assignee: E.I. Du Pont De Nemours And Company
Priority date: 1996-04-22
Filing date: 1997-04-03
Publication date: 1997-10-30

Abstract

Granules containing pesticidally active substances in a water soluble matrix of a polysaccharide and oside are disclosed, as are processes for their preparation.

Description

TITLE PESTICIDES TRAPPED IN EMULSIFIABLE GRANULES BACKGROUND OF THE INVENTION The present invention relates to granules that contain pesticidally active ingredients suitable for use in the agricultural industry.

Granules and microcapsules made from various natural and synthetic polymeric materials are known. Such materials include polyvinyl alcohol, arabic gum and α- cyclodextrin (see U.S. Patent Nos. 4,244,836 and 5,137,726, CA 2,060,745, EP 0 548 901 Al and JP 6-312904). Granules made from these materials have certain disadvantages. For example, they may have significant levels of active ingredient present outside the granule, and or they may have irregular shapes and unsmooth surfaces.

It is also known to make granules from mixtures of polysaccharides, including gum arabic and polyhydroxy compounds, including certain sugars (see U.S. Patent No. 3,971,852). This patent discloses such granules as being useful as carriers for oils destined for various end-uses. Generally mentioned amongst the end uses are fungicides, pesticides and herbicides.

SUMMARY OF THE INVENTION It has now been found that granules made from polysaccharides and osides are particularly suitable as carriers for agricultural chemicals that are either present in the granules without solvent, or with certain non-oil solvents.

Accordingly, the present invention provides a pesticide-containing granule that comprises a pesticidally active substance contained within a water-soluble matrix of a polysaccharide and an oside, and is characterized in that the pesticidally active substance is present either without solvent or is dissolved or dispersed in a solvent that is substantially immiscible with water selected from the group consisting of aromatic hydrocarbons, C₅-C₂o aliphatic hydrocarbons, Cj-Cjo halogenated hydrocarbons, Cg-C^ alcohols, C₅-C_{] 0} ketones, C₄-Cι₆ esters, oleates, C^-C^ amines, Cg-C^ ethers and Cg-C_jg acids. The present invention also provides a process for the preparation of the pesticide-containing granule of this invention which comprises removing the water from an aqueous dispersion of the components of the granules in a spray dryer, a fluidized bed dryer or a fluidized spray dryer.

DETAILS OF THE INVENTION Some of the advantages of the granules according to the present invention are that they allow retention of a high level of pesticide, and have low levels of extractable pesticide outside the granule, typically less than 5% by weight; they are free flowing, are substantially spherical and without cracks in their surface, and they provide a convenient way for converting a suspo-emulsion of a pesticide into a granule.

Certain terms used herein have the following meanings. "Polysaccharides" are solids characterized by solubility in water. They are primarily not the sweet, readily soluble saccharides like sugar but higher polysaccharides that may be natural, such as gum arabic and similar vegetable gums, or synthetic, such as degradation and modified products of starch; which usually form colloidal solutions. Certain starch degradation products such as dextrinized starch which are suitable polysaccharides for use in the invention contain a wide spectrum of saccharides of different molecular weights including a sufficient proportion in the polysaccharide molecular weight range to be good for forming granules and varying proportions of lower saccharides such as mono-, di- and trisaccharides.

The polysaccharide component may comprise a single polysaccharide or mixture of two or more polysaccharides. The preferred polysaccharide according to the present invention is arabic gum.

"Osides" are characterized by (a) solubility in water and at least partial solubility in the polysaccharide material or capability of at least partially dissolving such material (b) forming with the polysaccharide material a liquid melt having a softening range at appropriate temperatures with the ranges of proportions used, (c) forming with the polysaccharide material continuous aqueous phase in which the pesticidally active compound and optional solvents are dispersible as a discontinuous phase to form a stable emulsion, (d) plasticity of the surface of the particle formed from the emulsion as water is removed through a drying operation end (e) forming with the polysaccharide material a mixture that is in the solid state at the temperature of use. The useful osides can be classified in two groups: 1. Holosides, including glycerin, sorbitol, sucrose, mannitol, erythritol and ribitol.

2. Heterosides, containing other functional groups including glucuronolactone (lactone), sorbitan and mannitan (monoethers) and methyl-glucopyranoside (acetal). Preferred osides according to the invention are holoside is selected from the group consisting of sorbitol, sucrose, and mannitol.

An especially preferred combination of polysaccharide and oside is gum arabic and sucrose.

The proportion of polysaccaharide to oside in the matrix will vary depending upon the particular ones chosen. In the case of lower saccharides, it may be necessary to make adjustments in the proportion of the oside in order i ^btain the p; er balance of polysaccharide and osides to assure proper melt chi eristics sir the proportion of lower saccharides in the starch degradation products, while usually too 1. , to satisfy the requirements of the invention for oside, may be large enough to affect significantly the amount of added oside required to obtain the proper proportion of oside to polysaccharide in the product.

In general, the matrix will typically comprise 60-90 % by weight polysaccharide and 10-40 % by weight oside. W0 97/39626

"Pesticidally active substances" according to the present invention may be either liquids or solids. Solid substances may be either water-soluble or insoluble. Liquid substances will be water-insoluble or substantially insoluble. For the purposes of this invention, "substantially insoluble" means having a solubility of less than about 5 % v/v at room temperature.

The pesticidally active substances may be divided into but not limited to the following groups: amides, benzonitriles, carbamates dicarboximides, diazines, morpholines, organochlorines, organophosphosphates, propionates, pyrethroids, substituted ureas, quinazolinones, sulfonylureas, triazines, triazolones, triazoles and triazinones. Suitable pesticidally active substances that are solids to be used in the present invention are cymoxanil, dichlobenil, carbendazim, folpel, bromacil, lindane, chlorpyriphos, fenoxaprop-p-ethyl, tralomethrin, diuron, metsulfuron-methyl, atrazine, epoxiconazole, flusilazole and hexazinone.

Suitable pesticidally active substance that are liquids to be used in the present invention are propanil, bromoxynil, benfuracarbe, procymidone, pyridate, fenpropimorph, naled, haloxyfop-R and fenvalerate. Of note are embodiments where a second pesticidally active substance may be present as a solid dissolved or suspended in the liquid.

Examples of other suitable insecticides, fungicides and herbicides in the present invention can be found in the "Index Phytosanitaire", 1996, ACTA. Mixtures of pesticidally active substances may also be employed. Suitable mixtures for fungicidal use include mixtures comprising flusilazole, famoxodone and/or (4-S) 4- methyl-2-methylthio-4-phenyl-l-phenylamino-2-imidazoline-5-one. Typically in such mixtures, flusilazole, femoxodone or (4-S) 4-methyl-2-methylthio-4-phenyl-l-phenylamino- 2-imidazoline-5-one is from 10 to 90 percent by weight of the pesticidally active component with the remainder of that component being one or more other fungicides.

Of note is the combination comprising (a) (4-S) 4-methyl-2-methylthio-4-phenyl-l- phenylamino-2-imidazoline-5-one and (b) phosethyl aluminum, mancozeb, cymoxanil, dimethomorphe, oxadixyl or N-methyl-N-ethyl-2-(3,4-dimethoxyphenyl)-4- trifluoromethylbenzamide (see e.g., WO 93/24467 and WO 96/03044). Also of note are combinations comprising (a) famoxadone and (b) acypetacs, anilazine, azaconazole, azoxystrobin (ICIA5504), benalaxyl, benomyl, biphenyl, bitertanol, blasticidin-S, borax, Bordeaux mixture (tribasic copper sulfate), bromuconazole, bupirimate, butylamine, calcium polysulfide, captafol, captan, carbendazim, carboxin, chinomethionat, chloroneb, chlorothalonil, chlozolinate, copper hydroxide, copper oxychloride, copper salts, copper sulfate, cuprous oxide, cymoxanil, cyproconazole, cyprodinil (CGA 219417), dazomet, debacarb, dichlofluanid, dichlone, dichlorophen, diclomezine, dicloran, diethofencarb, difenoconazole, dimefhirimol, dimethomorph, diniconazole, diniconazole-M, dinocap, diphenylamine, dithianon, DNOC, dodemorph, dodine, edifenphos, epoxiconazole (BAS 480F), ethiπmol, ethoxyquin, etπdiazole, fenaπmol, fenbuconazole, fenfuram, fenpiclonil, fenpropidin, fenpropimo h, fentin, ferbam, feπmzone, fluazinam, fludioxonil fluoromide, fluquinconazole, flusilazole, flusulfamide, flutolaml, flutπafol, folpet, formaldehyde, fosetyl-aluminum, fubeπdazole, furalaxyl, guazatine, GY-81, hexachlorobenzene, hexaconazole, 8-hydroxyquιnolιne sulfate, hymexazol, ICIA0858, imazahl, lmibenconazole, iminoctad e, ipeonazole, lprobenfos, lprodione, isopamphos, isoprothiolane, kasugamycin, kresoxim-methyl (BAS 490F), mancopper, mancozeb, maneb, mepampyπm, mepronil, mercuric chloride, mercuric oxide, mercurous chloride, metalaxyl, metam, metconazole, methasulfocarb, methyl isothiocyanate, metiram, myclobutanil, nabam, naphthenic acid, natamycin, neo-asozin (ferric methanearsonate), nickel bιs(dιmethyldιthιocarbamate), mtrothal-isopropyl, nuarimol, octhi none, ofurace, oxadixyl, oxine-copper, oxycarboxin, pefurazoate, penconazole, pencycuron, pentachlorophenol, phenylmercury acetate, 2-phenylphenol, phosdiphen, phthahde, piperalm, polyoxins, probenazole, prochloraz, procymidone, propamocarb, propiconazole, propineb, pyrazophos, pyπfenox, pyπmethanil, pyroquilon, quintozene, SSF-109, sulfur, tar oils, tebuconazole, tecnazene, tetraconazole, thiabendazole, thifluzamide, thiophanate-methyl, thiram, tolclofos-methyl, tolylfluanid, triadimefon, tπadimenol, tπazoxide, tπcyclazole, tπdemoφh, tπflumizole, trifoπne, tπticonazole, vaiidamycin, vinclozohn, zineb and or ziram (see e g , Research Disclosure 38829, August 1996) "Solvents" mean organic solvents that are immiscible or substantially immiscible with water "Substantially immiscible" means having a miscibility of less than about 5 % v/v at room temperature. Suitable such solvents include aromatic hydrocarbons such as xylene and alkylnaphtalenes, C₅-C₂o aliphatic hydrocarbons, CI -CJ_Q halogenated hydrocarbons, C^-C^ alcohols such as butoxy-2-ethanol, octanol and dodecanol, C₅-CJ_Q ketones such as dnsobutylketone, cyclohexanone and isophorone, C -Ci6 esters such as acetate and phtalate, oleates, C₆-Cι₂ amines, Cg-C^ ethers, C₆-Cιg acids, and mixtures thereof.

Preferred solvents according to the present invention are methylnaphthalenes, methyl oleate, octanol, dnsobutylketone, dimethylglutarate, dibutylphtalate, and mixtures thereof Satisfactory components combined for the granules of this invention are listed in Table I

TABLl E l

Active Ingredient Polysaccharide Oside Solvent flusilazole arabic gum sucrose — flusilazole arabic gum sucrose methylnapthalene flusilazole arabic gum sucrose octanol flusilazole arabic gum sucrose dnsobutylketone flusilazole arabic gum sucrose dibutylphtalate flusilazole arabic gum sucrose dimethylglutarate flusilazole arabic gum sucrose ethyloleate flusilazole arabic gum sucrose methyloleate flusilazole arabic gum sucrose methyloleate flusilazole arabic gum sorbitol methyloleate flusilazole arabic gum mannitol methyloleate propanil arabic gum sucrose methyloleate bromoxynil arable gum sucrose methyloleate benfuracarbe arabic gum sucrose methyloleate procymidone arabic gum sucrose methyloleate pyridate arabic gum sucrose methyloleate fenpropimorph arabic gum sucrose methyloleate naled arabic gum sucrose methyloleate haloxyfop-R arabic gum sucrose methyloleate fenvalerate arabic gum sucrose methyloleate cymoxanil arabic gum sucrose methyloleate dichlobenil arabic gum sucrose methyloleate carbendazim arabic gum sucrose methyloleate folpel arabic gum sucrose methyloleate bromacil arabic gum sucrose methyloleate lindane arabic gum sucrose methyloleate chlorpyπphos arabic gum sucrose methyloleate fenoxaprop-p-ethyl arabic gum sucrose methyloleate tralomethπn arabic gum sucrose methyloleate diuron arabic gum sucrose methyloleate metsulfuron-methyl arabic gum sucrose methyloleate atrazine arabic gum sucrose methyloleate epoxiconazole arabic gum sucrose methyloleate hexazinone arabic gum sucrose methyloleate flusilazole + carbendazim arabic gum sucrose methyloleate flusilazole + fenpropimoφh arabic gum sucrose methyloleate flusilazole + epoxiconazole arabic gum sucrose methyloleate flusilazole + cymoxanil arabic gum sucrose methyloleate flusilazole + carbendazim arabic gum sucrose ...

Granules according to the present invention will typically comprise from 20 to 99 % by weight matrix, preferably 40 to 60 %, from 1 to 80 % by weight pesticidally active substance, preferably 10 to 40 % and 0 to 60 % by weight solvent, preferably 10 to 40 % (when solvent is present).

The granules will typically have a diameter from 0.01 to 3 millimeter. In addition, the granules of the present invention may be prepared with typical excipients used in the art, including dispersing agents, spreading agents, wetting agents, thickeners, binders, antioxidants, dewatering agents, mineral powder, etc.

If the surfactant is used as a dispersant, a spreader, a wetting agent or a penetrant, one or more nonionic or anionic surfactants may be admixed and used.

For example, nonionic surfactants include ethoxylated or propoxylated derivatives of alkyl or aryl phenols, fatty alcohols, castor oil, sorbitan esters, etc.

Anionic surfactants include polycarboxylic acid surfactants sodium lignin sulfonate, potassium lignin sulfonate and the like.

Suitable surfactants for use in this invention can be found in the McCUTCHEONS Surfactant Directory. Such surfactant is generally used in the range from 0 to 30 wt %, preferably from 0 to

20 wt % relative to the total amount of the preparation.

As fluidized auxiliaries, silica, clays, talc and the like may be used. Such fluidizing auxiliaries are generally used within the range from 0 to 20 wt %, preferably from 0 to 10 wt % relative to the total amount of the preparation. Granules according to the present invention are made by known processes, which can be generally described as removing the water from an aqueous dispersion of the components of the granules in a spray dryer, a fluidized bed dryer or a fluidized spray dryer. Fluidized spray drying is the preferred type of drying. A suitable such dryer is available from Niro A/S (Denmark) under the model designation Type FSD-16. Typical process conditions will be as follows: inlet temperature 100 - 300 °C outlet temperature 50 - 110 °C nozzle pressure 20 - 90 bars

EXAMPLE 1 Emulsifiable Granules by Fluidized Spray Drying (FSD)

A solution of an encapsulant was prepared by dissolving 75 parts sucrose and 175 parts arabic gum in 542 parts of water under agitation. An emulsifiable concentrate (EC) containing 45 by weight % of flusilazole, 42 by weight % of ethoxylated octyl phenol, 1 1.5 by weight % of ethoxylated arylphenol sulfate and 1.5 by weight % of Calcium dodecylbenzene sulfonate, was then added to the encapsulant solution to form an emulsion. The emulsion was spray dried in a fludized spray dryer (FSD-16), maintained at an air inlet temperature of 200 C and an air outlet temperature of 90 C at a feed rate of 85 liter per hour of emulsion. The collected product contained 42% of entrapped EC and 20% of flusilazole. The total extractable flusilazole is less than 5% and moisture is less than 2%. The average particle size of the emulsifiable granules d(0.5) is 760 microns.

EXAMPLE 2 Emulsifiable Granules made bv spray drying A solution of an encapsulant was prepared by dissolving 64 parts sucrose and 96 parts Arabic gum in 356 parts of water under agitation. An emulsion in water (EW) containing 30% by weight flusilazole is then added to the encapsulant solution to form an emulsion. The emulsion is spray dried in a Minor Mobile Atomizer, maintained at an air inlet temperature of 200 °C and an air outlet temperature of 95 °C at a feed rate of 3 liters per hour of emulsion. The collected emulsifiable granule product contains 45% of entrapped EC and 22% of flusilazole. The total extractable flusilazole is less than 2% and the moisture is less than 1%. The average particle size of the emulsifiable granules d(0.5) 35 microns.

Claims

CLAIMS What is claimed is:

1. A pesticide-containing granule comprising a pesticidally active substance contained within a water-soluble matrix of a polysaccharide and an oside compound, characterized in that the pesticidally active substance is present either without solvent or is dissolved or dispersed in a solvent that is substantially immiscible with water selected from the group consisting of aromatic hydrocarbons, C₅-C₂o aliphatic hydrocarbons, C_j-C₁₀ halogenated hydrocarbons, -C^ alcohols, C₅-C₁₀ ketones, C₄-C_j6 esters, oleates, C₆-C_]2 amines, C6-C12 ethers and

acids.

2. A granule according to Claim 1 wherein the polysaccharide is arabic gum and the oside is a holoside or an heteroside.

3. A granule according to Claim 2 wherein the holoside is selected from the group consisting of sorbitol, sucrose, and mannitol.

4. A granule according to Claim 1 wherein the pesticidally active substance is present in a granule as a liquid.

5. A granule according to Claim 4 wherein the pesticidally active substance that is present as a liquid is selected from propanil, bromoxynil, benfuracarbe, procymidone, pyridate, fenpropimoφh, naled, haloxyfop-R, and fenvalerate.

6. A granule according to Claim 5 wherein a second pesticidally active substance is present as a solid dissolved or suspended in the liquid.

7. A granule according to Claim 1 wherein the pesticidally active substance is present in the granule as a solid.

8. A granule according to Claim 6 or 7 wherein the pesticidally active substance that is present as a solid is selected from cymoxanil, dichlobenil, carbendazim, folpel, bromacil, lindane, chloφyriphos, fenoxaprop-p-ethyl, tralomethrin, diuron, metsulfuron- methyl, atrazine, epoxiconazole and hexazinone.

9. A granule according to Claim 1 wherein the pesticidally active substance is an amide, benzonitrile, carbamate dicarboximide, diazine, moφholine, organochlorines, organophosphosphate, propionate, pyrethroid, substituted urea, quinazolinone, sulfonylurea, triazine, triazolone, triazole or triazinone.

10. A granule according to Claim 1 wherein the solvent is selected from methylnapthalenes, methyloleate, octanol, diisobutylketone, dimethylglutarate, dibutylphtalate.

1 1. A granule according to Claim 1 wherein the matrix comprises from 20 to 99 % by weight matrix, from 1 to 80 % by weight pesticidally active substance and from 0 to 60 % by weight solvent.

12. A granule according to Claim 1 wherein having a diameter from 0.01 to 3 mm.

13. A granule according to Claim 1 wherein the pesticidally active substance is flusilazole.

14. A process for the preparation of a granule according to Claim 1 comprising removing the water from an aqueous dispersion of the components of the granules in a spray dryer, a fluidized bed dryer or a fluidized spray dryer.