TECHNICAL FIELD

The present invention relates to a method for the preparation of an agrochemical oil dispersion comprising a thickener which is an amide obtained by reacting a polyhydroxystearic acid with diethyiene triamine and/or triethylene tetramine in a specific molar ratio.

This invention also pertains to agrochemical oil dispersions comprising the above mentioned amide.

BACKGROUND ART

Agrochemical oil dispersions (OD) are stable suspensions of agrochemical active ingredients, such as pesticides and crop protection chemicals, in organic fluids, which may contain other dissolved active ingredients and are usually intended for dilution with water before use. Typical organic fluids include aromatic and non-aromatic hydrocarbons, halogenated aromatic and non- aromatic hydrocarbons, aromatic and non-aromatic ethers, esters or amides and oils, including, but not limited to, vegetable oils and paraffin oils. Oil dispersions are particularly useful for formulating oil insoluble solid active ingredients.

A disadvantage of the existing OD formulations is that such formulations frequently show phase separation after storage. Thus, storage even at ambient temperatures frequently leads to aggregation effects, lump formation or pronounced settling of the suspended phase. In the worst cases, the effects are irreversible, i.e. even shearing, for example by stirring, cannot re- homogenize the formulation.

A common method to solve this problem is to add to the dispersions, as anti- settling agent, a thickener that increases the viscosity of the system and acts as suspending agent by reducing the settling rate of the particles.

Typical thickeners for waterless organic systems include organoclays, such as Bentone®. Organoclays are made from natural smectite, hectorite or montmoriilonite clays by reacting the hydrophilic clay with quaternary ammonium compounds, so that it becomes organophilic and therefore compatible with non-aqueous media. The use of these thickeners is described for example in WO/2009/004281, EP 789,999, GB 2,067,407, EP 149,459 and GB 2,008,949. Unfortunately, organoclays have to be carefully dispersed and need the presence of a chemical activator in order to function as anti-settling agents with good gel strength. If the organoclay is not well dispersed or chemically activated the result is poor gel strength and hence limited physical stability of the product.

Other known thickeners are vegetable oil derivatives, silica derivatives and synthetic polymers that are described, for example, in WO/2008/135854 and US 5,599,768.

The handling of most of these thickeners is very difficult and/or harmful because they are mainly very fine and light powders. Furthermore, it is difficult to dissolve and homogenize them while avoiding the formation of gels or lumps and continued and careful monitoring of the process is required . For these reasons, a need still exist a thickener that improves the physical stability of oil dispersions and oil suspension concentrates of a variety of agrochemical active ingredients.

We have now found that a variety of agrochemical oil dispersions can be thickened using an oil-soluble amide obtained by reacting in a specific ratio a polyhydroxystearic acid (PHSA) with diethylene triamine (DETA), triethylene tetramine (TETA) or a mixture thereof.

This is especially surprising because several salts and amides obtained by reacting poly(hydroxy carboxylic) acids with amines and polyamines are known to be very efficient dispersants for non-aqueous systems and do not thicken organic mediums.

Among these compounds, PHSA based derivatives have also been described, for instance in GB 1,373,660, GB 2,001,083 and US 5,000,792 that disclose po!yhydroxy carboxylic) acids reacted with different polyamines, such as 3- dimethyiamino-propylamine, ethylene diamine and poly(ethyleneimine), for use as dispersing agents for pigments in organic liquids.

In US 6,753,003 the generic reaction products of PHSA with polyamines, (and among them some of the well known commercial dispersants Solsperse® from Noveon) are described as auxiliaries for anhydrous dithiocarbamate liquid formulations; according to the description they can be used as dispersant during the grinding step, but are not considered to act as thickeners.

None of these patent documents, however, discloses the use of the amide of the invention as thickener for agrochemical oil dispersions. The thickener of the invention facilitates the preparation and storing of oil dispersions (that are also meant to include oil concentrates) even in hot climates, for their effective use in agronomic applications.

Accordingly, the present invention provides a stable dispersion of certain agrochemical ingredients in an oil and a method for forming the stable dispersion.

The term oil dispersion (OD) is to be understood as meaning a dispersion concentrate based on an organic vehicle in which one or more solid active compounds are suspended; further active ingredients may be dissolved in the organic solvent.

DISCLOSURE OF THE INVENTION

It is therefore an object of the present invention a method for the preparation of an agrochemical oil dispersion comprising : i) preparing a mixture of at feast one solid agrochemical active ingredient having average particle size below 20 micron and an oil; ii) adding to the mixture a thickener which is an amide obtained by reacting a) polyhydroxystearic acid (PHSA) with acid number comprised between 35 and 80 mg _K 0H/ ^{a r|} d b) diethylene triamine and/or triethylene tetramine, the molar ratio of a) and b) being comprised between 0.8 and 2.5, said agrochemical oil dispersion comprising from 0.01 to 60 by weight (wt%) of the active ingredient, from 10 to 90 wt% of the oil and from 0.1 to 15 wt% of the thickener.

It is a further object of the invention an agrochemical oil dispersion comprising : from 0.01 to 60 wt% of at least one solid agrochemical active ingredient having average particle size below 20 micron, from 10 to 90 wt% of an oil; from 0.1 to 15 wt% of a thickener which is an amide obtained by reacting a) polyhydroxystearic acid (PHSA) with acid number comprised between 35 and 80 mg oH/g and b) diethylene triamine and/or triethylene tetramine, the molar ratio of a) and b) being comprised between 0.8 and 2.5. The use in agriculture of the agrochemical oil dispersion described in the previous paragraph for the treatment of plants, crops, fields, etc. is a further object of the invention.

DETAILED DESCRIPTION.

The amides obtained by reacting polyhydroxystearic acid having acid number comprised between 35 and 80 mg _K 0H/g with diethylene triamine and/or triethylene tetramine in a molar ratio comprised between 0.8 and 2.5 are surprisingly able to increase the Brookfield ® viscosity of the agricultural oil of more than 20% when dosed at 4 wt%.

Preferably the amide is obtained by reacting :

a) PHSA with an acid number comprised between 45 and 65 mg _K oH/g and b) diethylene triamine and/or triethylene tetramine;

the molar ratio of a) and b) being comprised between 0.9 and 1.5.

The most preferred amide is the monoamide which is obtained by reacting the PHSA with diethylene triamine and/or triethylene tetramine in a molar ratio of about 1.

The above preferred amides show unexpectedly high thickening performances in oils, especially in vegetable oils and paraffin oils.

The polyhydroxystearic acid a) can be prepared by intra-esterification carried out according to methods well known to those skilled in the art. Commercial 12-hydroxystearic acid normally contains up to 15% wt of stearic acid and other non-hydroxycarboxylic acids as impurities and can be conveniently used without further admixture to produce a polymer of molecular weight about 600-1600. The intraesterification of the hydroxycarboxylic acid may be achieved by heating the starting materials either or not in a suitable hydrocarbon solvent such as toluene or xylene and azeotroping off the formed water. The reaction may be carried out at temperature up to 250 °C, conveniently at the reflux temperature of the solvent. Since the hydroxyl group is secondary, the temperature should not be so high as to lead to dehydration of the acid molecule. Typical catalysts for the esterification, such as p-toluenesulphonic acid, zinc acetate, zirconium naphthenate or tetrabutyi titanate, may be included, with the objective of either increasing the rate of reaction at a given temperature or of reducing the temperature required for a given rate of reaction. The end-point of the reaction is determined by standard method ASTM D1980-87, which describes the determination of the acid value (or acid number).

Also the subsequent amidation with DETA and/or TETA may be carried out according to methods well known to those skilled in the art, by heating up to 250 °C a proper amount of poly(hydroxycarboxy!ic) acid and amine(s), either or not in a suitable hydrocarbon solvent such as toluene or xylene and azeotroping off the formed water, with or without catalysts such as p- toluenesulphonic acid, zinc acetate, zirconium naphthenate or tetrabutyi titanate. The end-point of the reaction is considered to be reached when the acid number of the reaction mixture, determined by standard method AST - D1980-87, is below 15 mg _K0 H/g, preferably below 10 mg _K oH/g- Preferably the agrochemical oil dispersion of the invention comprises: from 0.5 to 50 wt% of at least one agrochemical active ingredient; from 20 to 80 wt% of an oil and from 1.5 to 7.0 wt%, more preferably from 3.0 to 7.0 wt%, of the amide described above.

Suitable agrochemical active ingredients for the agrochemicai oil dispersion are substantially solid materials that are oil-insoluble at room temperature such as, for example, fungicides, bactericides, insecticides, acaricides, nematicides, herbicides, aracnicides, insect growth regulators, repellents, antibiotics, plant growth regulators, plant nutrients and mixture thereof.

Examples of fungicides which may be mentioned are:

2-aniiino-4-methyl-6-cyciopropyl-pyrimidine; 2',6'-dibromo-2-methyt-4'- trifluoro-methoxy-4 ^, -trifluoromethyl-l,3-thiazole-5-carboxanilide; 2,6-dichloro -N-( 4-trifluoro-methylbenzyl)-benzamide; (E)- 2-methoxsmino-N -methyl- 2- (2-phenoxyphenyl)-acetamide; 8-hydroxyquinoline sulphate; methyl (E)- 2-{ 2~[6-(2-cyanophenoxy)-pyrimidin-4-yloxy]-phenyl}-3-methoxyac rylate;

methyl (E)methoximino[ alpha-( o-tolyloxy)-o-to!yl ]-acetate; 2-pheny!phenoi (OPP), aldimorph, ampropylfos, ani!azine, azaconazole, benalaxyl, benodanil, benomyl, binapacryl, biphenyl, bitertanol, blasticidin-S, bromuconazole, bupirimate, buthiobate, calcium polysulphide, captafol, captan, carbendazim, carboxin, quinomethionate, chloroneb, chloropicrin, chlorothalonii, chlozolinate, cufraneb, cymoxanil, cyproconazole, cyprofuram, carpropamide, dichlorophen, diclobutrazole, dichlofluanid, diclomezin, dicloran, diethofencarb, difenoconazoie, dimethirimol, dimethomorph, diniconazole, dinocap, diphenylamine, dipyrithion, ditalimfos, dithianon, dodine, drazoxolon, edifenphos, epoxyconazole, ethirimoi, etridiazole, fenarimol, fenbuconazole, fenfuram, fenitropan, fenpiclonil, fentin acetate, fentin hydroxide, ferbam, ferimzone, fluazinam, fludioxoni!, fluoromide, fiuquinconazole, flusilazole, flusulfamide, flutoianil, flutriafol, foipet, fosetyl-aluminium, fthalide, fuberidazole, furalaxyl, fenhexamide, guazatine, hexachlorobenzene, hexaconazole, hymexazole, imazalil, imibenconazole, iminoctadine, iprobenfos (IBP), iprodion, isoprothiolan, iprovalicarb, kasugamycin, copper preparations, such as ; copper hydroxide, copper naphthenate, copper oxychloride, copper sulphate, copper oxide, oxine-copper and Bordeaux mixture; mancopper, mancozeb, maneb, mepanipyrim, mepronil, metalaxyl, metconazole, methasulfocarb, methfuroxam, metiram, metsulfovax, mydobutanil, nickel dimethyldithiocarbamate, nitrothalisopropyl, nuarimol, ofurace, oxadixyl, oxamocarb, oxycarboxine, pefurazoate, penconazoie, pencycuron, phosdiphen, pimaricin, piperalin, polyoxine, probenazofe, prochloraz, procymidon, propamocarb, propiconazole, propineb, pyrazophos, pyrifenox, pyrimethanil, pyroquilon, quintozene (PCNB), quinoxyfen, sulphur and sulphur preparations, tebuconazole, tecloftalam, tecnazene, tetraconazole, thiabendazole, thicyofen, thiophanate-methyl, thiram, toldlophos-methyl, tolylfluanid, triadimefon, triadimenol, triazoxide, trichlamide, tricyclazole, tridemorph, trifiumizole, triforin, triticonazofe, trifioxystrobin, vaiidamycin A, vinclozo!iii, zineb, ziram, ciproconazole, dodine, fenamidone, fenexamide, fluopicolide, fluoxastrobin, fosetyl-aiuminium, iprovalicarb, pencycuron, prothioconazole, spiroxamina, triadimenol, trifioxystrobin, azoxystrobin, acibenzolar-S-methyl, ciprodinil, mandipropamid, fenpropidin, boscalid, kresoxim-methyl, pyraciostrobin, dimetomorf, fenpropimorf, metraphenone, tolclofos-methyl and 2-[2-(l- chIoro-cyclopropyl)-3-(2-chlorophenyl)- 2-hydroxypropyl]- 2, 4-dihydro- [l,2,4]-triazole-3-thione.

Examples of bactericides which may be mentioned are : bronopol, dichlorophen, nitrapyrin, nickel dimethyldithiocarbamate, kasugamycin, octhilinon, furancarboxylic acid, oxytetracycline, probenazole, streptomycin, tecloftalam, copper sulphate and other copper preparations. Examples of insecticides, acaricides and nematicides which may be mentioned are :

abamectin, acephate, acrinathrin, alanycarb, aldicarb, aiphamethrin, amitraz, avermectin, AZ 60541, azadirachtin, azinphos A, azinphos M, azocyclotin, Bacillus thuringiensis, 4-bromo-2-(4-chlorphenyl)-l-(ethoxymethyl)-5- (trifiuoromethyl)-pyrrole-3-carbonitrile, bendiocarb, benfuracarb, bensultap, betacyfluthrin, bifenthrin, BPN!C, brofenprox, bromophosa, bufencarb, buprofezin, butocarboxine, butylpyridaben, cadusafos, carbaryt, carbofuran, carbophenothion, carbosulfan, cartap, chloethocarb, chlaretoxyfos, chlorfenvinphos, chlorfluazuron, chlormephos, N-[(6-chioro-3-pyridinyl)- methy!]-N'-cyano-N-methyl-ethaneimidamide, chlorpyrifos, chlorpyrifos M, cis- resmethrin, clocythrin, clofentezin, cyanophos, cycloprothrin, cyfluthrin, cyhalothrin, cyhexatin, cypermethrin, cyromazin, deltamethrin, demeton-M, demeton-S, demeton-S-methyl, diafenthiuron, diazinon, dichlofenthion, dichlorvos, dicliphos, dicrotophos, diethion, diflubenzuron, dimethoate, dimethylvinphos, dioxathion, disuifoton, emamectin, esfen valerate, ethiofencarb, ethion, ethofenprox, ethoprophos, etrimphos, fenamiphos, fenazaquin, fenbutatin oxide, fenitrothion, fenobucarb, fenothiocarb, fenoxycarb, fenpropathrin, fenpyrad, fenpyroximate, fenthion, fenvalerate, fipronil, fluazuron, flucycioxuron, flucythrinate, flufenoxuron, fiufenprox, fluvalinate, fonophos, formothion, fosthiazate, fubfenprox, furathiocarb, HCH, heptenophos, bexaflumuron, hexythiazox, imidacloprid, iprobenfos, isazophos, isofenphos, isoprocarb, isoxathion, ivermectin, lambdacybalothrin, iufenuron, malathion, mecarbam, mevinphos, mesulfenphos, metaldehyde, methacrifos, methamidophos, methidathion, methiocarb, methomyl, metoicarb, mi!bemectin, monocrotophos, moxidectin, naled, NC 184, nitenpyram, omethoate, oxamyl, oxydemethon M, oxydeprofos, parathion AL, parathion ML, permethrin, phenthoate, phorate, phosalon, phosmet, phosphamidon, phoxim, pirimicarb, pirimiphos M, pirimiphos A, profenophos, promecarb, propapbos, propoxur, prothiophos, prothoate, pymetrozine, pyrach!ophos, pyridaphenthion, pyresmethrin, pyrethrum, pyridaben, pyrimidifen, pyriproxifen, quinalphos, salithion, ebufos, silafluofen, sulfotep, sulprofos, tebufenozide, tebufenpyrad, tebupirimiphos, teflubenzuron, tefluthrin, temephos, terbam, terbufos, tetrachlorvinphos, thiacioprid, thiafenox, thia- methoxam, thiodicarb, thtofanox, thiomethon, thionazine, thuringiensin, traiomethrin, transfiuthrin, triarathen, t iazophos, triawron, trichlorfon, triflu- muron, trimethacarb, vamidothion, XMC, xyiylcarb, zetamethrin, ethoprophos, fenpyroximate, methoxyfenozide, spinosad, spirodiclofen, thiacioprid, cypermethrine, alfacypermethrine, alphametrine e metaflumizone.

Examples of herbicides which may be mentioned are:

anilides, such as, for example, diflufenican and propanil; arylcarboxylic acids, such as, for example, dichlorpicolinic acid, dicamba and picloram; aryloxyalkanoic acids, such as, for example, 2,4-D, 2,4-DB, 2,4-DP, Fluroxypyr, MCPA, MCPP and triclopyr; aryloxy-phenoxy-alkanoic acid esters, such as, for example, diclofop-methyl, fenoxapropethyl, Fluazifop-butyl, haloxyfop-methyl and quizalofop-ethyl; azinones, such as, for example, chlo- ridazon and norflurazon; carbamates, such as, for example, chlorpropham, desmedipham, phenrnedipham and propham ; chloroacetani!ides, such as, for example, alach!or, acetochlor, butachlor, metazach!or, metolachior, pretilachlor and propachlor; dinitroarilines, such as, for exam ple, oryzalin, pendimetha!in and triflura!in ; diphenyl ethers, such as, for example, acifluorfen, bifenox, fluoroglycofen, fomesafen, halosafen, lactofen and oxyfluorfen ; ureas, such as, for example, chlortol uron, diuron, fiuometuron, isoproturon, linuron and methabenzthiazuron ; hydroxylamines, such as, for exa mple, alloxydim, clethodim, cycloxydim, sethoxydim and tralkoxydim ; imidazolinones, such as, for example, imazethapyr, i maza methabenz, imazapyr and imazaquin ; nitriles, such as, for exa mple, bromoxynil, dichlobenil and ioxyni! ; oxyaceta mides, such as, for example, mefenacet; sulfonylureas, such as, for example, a midosulfuron, bensulfuron-methyl, ch lo- rimuron-ethyi, chlorsulfuron, cinosu lfuron, metsulfuron-methy!, nicosulfuron, pri misulfuron, pyrazosulfuron-ethyl, thifensulfuron-methyl, triasulfuron and tribenuron-methyl ; thiocarbamates, such as, for exa mple, butylate, cycloate, diallate, EPTCL, esprocarb, molinate, prosulfocarb, thiobencarb and triallate; triazines, such as, for example, atrazine, cyanazine, si mazine, simetryne, terbutryne and terbutylazine; triazinones, such as, for exa mple, hexazinon, metarnitron and metribuzin ; others, such as, for exa mple, aminotriazole, benfuresate, bentazone, cinmethylin, clomazone, clopyralid, difenzoqual, dithiopyr, ethofumesate, fiuorochloridone, g lufosinate, glyphosate, isoxaben, pyridate, quinchlorac, quin merac, su lphosate and tridiphane, aclodifen, bap, bispyribac-sodiu m, ethoxysulfuron, flufenacet, foramsulfuron, iodosulfuron methyl sodiu m, isoxadifen ethyl, isoxaflutole, mefenpyr diethyl, mesosulfuron methyl, sulcotrione, mesotrione, prosulfuron, florasu la m, clodinafop propargyl, pinoxaden, trinexapac ethyl, dimethenamide-P, imazamox, profoxydim, tepraloxidim. In addition, 4-amino-N-(l,l-dimethylethyl)-4,5-dihydro-3-(l- methylethyl)-5-oxo-lH-l,2,4-triazole-carboxamide and 2-4,5-dihydro-4- methyS-5-oxo-3-propoxy-lH-l,2,4-tnazoi-lyl)carbonyf)amino)su lfonyl) methyl benzoate may be mentioned.

Examples of plant growth regulators which may be mentioned are chlorocholine chloride and ethephon.

Examples of repellents which may be mentioned are diethyl-toluamide, ethylhexane-diol and buto-pyronoxyl.

Other classes of pesticides that are suitable for formulating as oil dispersions, such as those which are substantially oil-insoluble solid materials at room temperature , will be clearly understood by those skilled in the art or can be found, for example, in "The Pesticide Manual", 15th edition, The British Crop

Protection Council, 2009, and the literature cited therein.

Preferred classes of pesticides suitable for formulating the oil dispersion of the invention are sulfonylureas, sulfamylureas, sulfonamides, imidazolinones, pyrimidinyloxypyridinecarboxylic or pyrimtdyloxybenzoic acid derivatives; triketones; neonicotinoids; avermectins; pyrethroids; bisamides; triazoies; mandelamides and strobilurins; alkanamides ; anilinopyrimidines; arylaminopropionic acids; aryloxyalkanoic acids; aryloxyphenoxypropionates; benzamides ; benzimidazoles; chloroacetamides; cyclohexanedione oximes; dicarboximides; dinitroanilines; diphenyl ethers; imidazoles; hydroxybenzonitriles; isoxazoles; morpholines; guanidines; carbamates, dithiocarbamates, dimethyldithiocarbamates; phosphonates; phthalimides; sulphamides; non-ester pyrethroids; organophosphorus; oxime carbamates; phenyla mides; phosphinic acids; pyrazoles ; pyridines; pyridinecarboxamides; pyridinecarboxyiic acids; quinolinecarboxylic acids; semi-carbazones; triazines; triazinones; ureas, benzoyiureas.

Most preferred agrochemical active ingredient belong to the class of sulfonylurea herbicides such as amidosulfuron, azimsulfuron , bensulfuron- methyl , chlorimuron-ethyi, ch iorsulfuron, cinosulfuron, cyclosulfamuron, etha metsulfuron-methyl, ethoxysulfuron, flazasu ifuron, flupyrsulfu ron-methyl- sodium , fora msulfuron, halosulfuron-methyl, imazosulfuron, iodosulfuron- methyl-sodium, metsulfuron-methyl , nicosulfuron, oxasulfuron, primisu ifuron- methyl , prosulfuron, pyrazosulfuron-ethyl, rimsulfuron, sulfometuron-methyl, sulfosu lfuron, thifensulfuron-methyl, triasulfuron, tribenuron-methyl, trifloxysulfuron, triflusulfuron-methyl .

Among the sulfonylureas, nicosulfuron is particula rly preferred .

Examples of plant nutrients which may be mentioned are customary inorganic or organic fertilizers for supplying plants with macro- and/or micro-nutrients, such as : ammonia salts, such as ammonium sulfate, ammoniu m bisulfate, ammonium sa lts of carboxylic acids, ammoniu m ch loride, a m monium carbonate, am moniu m phosphate, urea and urea derivatives; phosphate sources, such as phosphoric salts (MAP monoa m monium phosphate, DAP diam moniumphosphate) ; potash sources, like potassium phosphate and mono- or di-potassium carbonate; compounds containing micronutrients and secondary nutrients li ke Zinc, Manganese, Magnesium, Iron, Calciu m, Nickel, Moiibdenum, Sulfur, Boron, and their chelated salts; polycarboxylic acids, such as citric acid ; and mixture thereof; protein derivatives and hydrolyzed proteins and mixture thereof. Preferred plant nutrients are MAP, ammonium sulfate , sulfur, urea and urea derivatives.

The oil is a water-insoluble liquid organic medium and may be any of those agricultural oils commonly used in the trade for making oil dispersions for agricultural use. Suitable agricultural oils in the dispersions of the invention are, for example :

• linear or branched C ₈ to C ₃₀ paraffins having boiling points above 140 °C (paraffin oils), for example octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, their mixtures, or mixtures thereof with higher boiling homologs, such as hepta-, octa-, nona-decane, eicosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, and the branched chain isomers thereof;

• aromatic or cycioaliphatic, which may be unsubstituted or substituted, C ₇ - to Ci ₈ -hydrocarbon compounds such as mono- or polyalkyl-substituted benzenes, or mono- or polya!kyl-substituted naphthalenes;

• vegetable oils such as Iiquid triglycerides for example olive oil, kapok oil, castor oil, papaya oil, camellia oil, palm oil, sesame oil, corn oil, rice bran oil, peanut oil, cotton seed oil, soybean oil, rapeseed oil, linseed oil, tung oil, sunflower oil, safflower oil, or also transesterification products thereof, e.g. alkyl esters, such as rapeseed oil methyl ester or rapeseed oil ethyl ester;

• animal oil, such as whale oil, cod-liver oil, or mink oil;

• iiquid esters of Ci to C ₁₂ monoalcohols or polyols, for example butanol, n- octanol, i-octanol, dodecanoi, cyclopentanol, cyclohexanol, cyclooctanol, ethylene glycol, propylene glycol or benzyl alcohol, with C ₂ to Ci _Q carboxylic or polycarboxylic acids, such as caproic acid, capric acid, caprylic acid, peiargonic acid, succinic acid and glutaric acid; or with aromatic carboxylic acids such as benzoic acid, toluic acid, salicylic acid and phthalic acid. Esters which can be used in the oil dispersions of the invention are thus, for example, benzyl acetate, caproic acid ethyl ester, peiargonic acid ethyl ester, benzoic acid methyl or ethyl ester, salicylic acid methyl, propyl, or butyl ester, diesters of phthalic acid with saturated aliphatic or alicyclic Ci to C ₁₂ alcohols, such as phthalic acid dimethyl ester, dibutyl ester, diisooctyt ester;

• liquid amides of Ci-C ₃ amines, aikylamines or alkanolamines with C ₆ - C ₁₈ carboxylic acids;

• or mixtures thereof.

Preferably the oil is obtained from renewable resources and is corn oil, soybean oil, sunflower oil or rapeseed oil or transesterification products thereof such as rapeseed oil methyl esters, ethyl esters, propyl esters, butyl esters etc. According to a particular embodiment, the oil is a paraffin oil or a vegetable oil.

In a preferred embodiment the agrochemical oil dispersion of the invention further comprises from 5 to 30 wt%, preferably from 5 to 20 wt%, of surfactants, such as emulsifiers and dispersants. Surfactants are used not only to improve dispersion and to emulsify oil upon dilution in water, but also to increase suspension stability, wetting ability, penetration and translocation, and to provide the mixing ability and suspension/emulsion stability of a product after dilution. As surfactants, anionic, cationic, non-ionic and ampholytic surfactants and mixtures thereof can be used. Suitable surfactants are, for example, nonionic emulsifiers and dispersants, such as :

• polyalkoxylated, preferably polyethoxylated, saturated and unsaturated aliphatic alcohols, having 8 to 24 carbon atoms in the alkyl radical, which is derived from the corresponding fatty acids or from petrochemical products, and having 1 to 100, preferably 4 to 40, ethylene oxide units (EO);

• polyalkoxylated, preferably polyethoxylated, arylalkylphenols, such as, for example, tristyrylphenol having an average degree of ethoxyiation of between 8 and 80, preferably from 16 to 40;

• polyalkoxylated, preferably polyethoxylated, alkylphenols having one or more alkyl radicals, such as, for example, nonylphenol or tri-sec- butylphenol, and a degree of ethoxyiation of between 2 and 40, preferably from 4 to 20;

• polyalkoxylated, preferably polyethoxylated, hydroxyl-fatty acids or glycerides which contain hydroxyl-fatty acids, such as, for example, castor oil, having a degree of ethoxyiation of between 10 and 80;

• sorbitan or sorbitol esters with fatty acids or polyalkoxylated, preferably polyethoxylated, sorbitan or sorbitol esters;

• polyalkoxylated, preferably polyethoxylated, amines;

• di- and tri-block copolymers, for example from alkylene oxides, for example from ethylene oxide and propylene oxide, having average molar masses between 200 and 8000 g/mol, preferably from 1000 to 4000; • aikylpoiyg!ycosides or polyalkoxylated, preferably polyethoxylated, alkylpolyglycosides.

Preferred nonionic surfactants are polyethoxylated alcohols, preferably from renewable resources, such as ethoxylated (4-8 EO) C _i2 -Ci4 natural alcohol; polyethoxylated triglycerides which contain hydroxyfatty acids and polyethylene oxide/polypropylene oxide block copolymers.

Also suitable are anionic surfactants, for example:

• polyalkoxylated, preferably polyethoxylated, surfactants which are ionically modified, for example by conversion of the terminal free hydroxy! function of the alkylene oxide block into a sulfate or phosphate ester;

• alkali metal and alkaline earth metal salts of alkylarylsulfonic acids having a straight-chain or branched alkyl chain ;

• alkali metal and alkaline earth metal salts of paraffin-sulfonic acids and chlorinated paraffin-sulfonic acids;

• polyelectro!ytes, such as lignosulfonates, condensates of naphthalenesulfonate and formaldehyde, polystyrenesulfonate or sulfonated unsaturated or aromatic polymers;

• anionic esters of alkylpolyglycosides, such as alkylpolygiucoside sulfosuccinate or citrate;

• sulfosuccinates which are esterified once or twice with linear, or branched aliphatic, cyc!oaliphatic and/or aromatic alcohols, or sulfosuccinates whichare esterifted once or twice with (poly)alkylene oxide adducts of alcohols. Preferred anionic surfactants are, for example, salts of aikylarylsu!fonic and sulfosuccinic acids, and polyelectrolytes from the poiycondensation of naphthalenesuifonate and formaldehyde.

Examples of cationic and ampholytic surfactants are quanternary ammonium salts, alkyl amino acids, and betaine or imidazoline amphotensides.

The agrochemical oil dispersion of the invention can comprise from 0.01 to 10 % wt of additional thickeners to improve the stability of the composition. Suitable additional thickeners are for example thickeners based on natural polymers, such as cellulose derivatives, natural oils and derivatives thereof, such as hydrogenated castor oil, bentones and modified silica. Natural oils and derivatives thereof, are the preferred additional thickeners.

The oil dispersion according to the invention can comprise from 0.5 to 35 wt% of adjuvants commonly used in this field and well known to those expert in the art, such as wetting agents, antidrift agents, adhesives, penetrants, stickers and spreaders.

In addition to each of the aforementioned components said oil dispersion may also comprise from 0.1 to 10 wt% of other agronomic additives and "crop management" substances such as oil-soluble agrochemical active ingredient, water mixing and/or water soluble carrier and/or deflocculat ^' ton agents (e. g. kaolin, Mgnin compounds), antifoam agents (e. g. silicon-based), antifreeze agents, dyes (e. g. azo dyes), preservatives (e, g. biocide and/or antioxidant), fillers, perfumes, evaporation inhibitors, pH modulators, etc.

The oil suspension concentrates according to the invention can be prepared in a manner known per se. In the method of the invention, the solid active ingredients are expediently employed in the finely ground state, that is as a micronized powder of less than 20 microns in size on average, preferably of less than 10 microns, or they may be reduced to this particle average size during step i).

In one embodiment it is possible to prepare the mixture of step i) by first coarse wet-milling and then fine wet-milling the active ingredient, so that the final average particle size is below 20 microns, preferably below 10 microns, in the presence of the oil, Milling can be carried out in a colloid mill, ball mill, sand mill, and preferably in grinding ball mills.

In a further embodiment it is possible to prepare the mixture of step i) by mixing the oil, the possible other liquid additives and the solid ingredients that have been preliminarily pulverized to a particle size of from about 20 to 50 microns by a dry mill, and then subjecting the mixture to fine treatment by a wet-mill, such as a ball mill, a sand mill etc., so that the final average particle size is below 20 microns, preferably below 10 microns.

Because of the high thickening power of the amides of the invention, in the last two embodiments, they shall be added after milling. The thickener can be poured into the liquid as such, preferably heated at a temperature above 40 °C, or can be predispersed or predissolved in the oil and then added to the micronized mixture.

The agrochemical oil dispersions of the invention have Brookfieid® viscosity of at least 300 mPa*s, preferably of at least 1000 mPa*s, at 25°C, and usually below 50,000 mPa*s, preferably below 20,000 mPa*s, at 25°C. The agrochemical oil dispersion can be diluted with water or water solutions of agronomic compounds before use to produce a sprayable composition which is used in treating plants or increasing plant growth, Dilution in water usually results in suspensions, emulsions, suspoemulsions or solutions of the agrochemical active ingredient at a concentration of at least 0.001 g/l. It may be advantageous to add, to the aqueous composition obtained, further agrochemical active substances and/or adjuvants and additives conventionally used for application, for example stickers or antidrift agents.

The invention also relates to aqueous compositions obtained by dilution of an oil dispersion according to the present invention.

The invention also relates to a method of treating crop field which comprises applying to the plants or to the locus thereof an effective amount of an aqueous compositions obtained by dilution of an agrochemical oil dispersion according to the present invention. Application may be made by ground or aerial spray equipment. The amount of active ingredient applied may vary within a relatively wide range. It depends essentially on the nature of the desired effect. In general, the application rates are at least 0.01 g of active ingredient per hectare of soil surface.

EXAMPLES

Preparation of poly 'hydroxy stearic acid (PHSA 1 and PHSA 2)

1500 g of commercial 12-hydroxystearic acid were transferred into a reaction vessel equipped with stirrer, thermometer and a distillation unit in order to remove the water generated by the reaction. 3.0 g of p-toluenesulfonic acid monohydrate were added under stirring at a temperature of about 100°C. The reaction mixture was heated to 180 °C and maintained at this temperature until the acid number reaches a value comprised between 45 and 80 mg _K iWg- Two different PHSA were prepared with different final acid number (see Table 1).

Table 1

Preparation of the Amides

The PHSAs prepared as described in the previous paragraph and different amines were charged in a reactor similar to the vessel used in Example 1 (see Table 2 for the chemical description of the amines and the moles and molar ratio of the reagents) . The reaction mixtures were heated under stirring at 180 - 200 °C and kept at this temperature until the acid number reaches a constant value.

Thickening Test

4 g of each amides of the previous paragraph, are mixed stirring vigorously with 96 g of oil; Brookfield® viscosity of the various solutions is determined at 25 °C after 24 hours (10 rpm, s. 3). Polyhydroxystearic acid (PHSA 1) and Solsperse 11000 (commercialized by Lubrizol) were included as comparative samples. The results in mPa _* s are reported in Table 3; they show that the best thickening results are obtained with the amide obtained by reacting polyhydroxystearic acid with diethylene triamine and/or triethylene tetramine in a molar ratio between comprised between 0.9 and 1.5, and in particular with the monoamide of diethylene triamine and triethylene tetramine.

Table 2

* Comparative

Table 3 - Thickening test

* Comparative

**white mineral oil (paraffin oil) from Exxon Mobil Corp.

***aromatic hydrocarbon oil from Exxon Mobile Corp. Oil Dispersion Stability Test

The agrochemical oil dispersions were prepared by vigorously mixing part of the oil, the surfactants and the different agrochemical active ingredients. The mixtures were milled until a optimal particle size distribution was reached (D50 < 2μΓη ; D90 <5μηη; determined with a laser light scattering spectrometer Coulter LS13320). A thickener of the invention (PIC295), as such or pre- disso!ved at a concentration of 25 wt% in the oil, was added after milling to the various mixtures. The recipes of the oil dispersions can be summarized as reported in Table 4-6.

Table 4

Table 5

Table 6

In the Oil Dispersion Stability Test the following products are used : Bayol 85 = white mineral oil (paraffin oil) from Exxon Mobil Corp. ; Solvesso 200 = aromatic hydrocarbon oil from Exxon Mobile Corp.

Emuison C09 = ethoxylated castor oil from Lamberti;

Emulson AG/18C = ethoxylated castor oii condensed with olein from Lamberti; Emuison AG/7717 = ethoxylated tristyrylphenol from Lamberti;

Emuison AG/OB5 = ethoxylated fatty alcohol from Lamberti;

Imbirol OD = dioctyl-sulphosuccsnate in solvent from Lamberti.

HCO = Hydrogenated Castor Oil

The oil dispersion stability test ( ^" storage stability test) (see results in Table 7) was performed at room temperature and at 40 °C on each agrochemical oil dispersion prepared as described above in order to monitor the presence or absence of formation of an oil phase or of a creamy phase in the composition, the presence or absence of the occurrence of aggregation or precipitation, and the presence or absence of the formation of a supernatant over time. About 100 ml of the agrochemical oil dispersions are sealed in glass containers and allowed to rest at room temperature (r.t.) and in a oven at 40 °C.

When the syneresis of the agrochemical oil dispersion is equal to or below 10% V/V the dispersion is considered stable. The agrochemical oil dispersions of the invention, and in particular the nicosulfuron dispersions containing a vegetable oil or a paraffin oil, have a good stability over time also at elevated temperatures. These dispersions are easily pourable and dispersible into water using minimal agitation and have very little tendency to form films in water, which can easily plug nozzle sieves. Tabie 7 - Storage stability test

Syn = amount of supernatant liquid (syneresis) expressed as % V/V