WO2010064266A1

WO2010064266A1 - Liquid composition for pesticide concentrates

Info

Publication number: WO2010064266A1
Application number: PCT/IT2008/000740
Authority: WO
Inventors: Valter Lopes Moreno; Ishiki Yoshimi; Vladimir Jose Grana; Bassi Giuseppe Li
Original assignee: Lamberti S.P.A.
Priority date: 2008-12-03
Filing date: 2008-12-03
Publication date: 2010-06-10
Also published as: BRPI0823292A2

Abstract

The present invention relates to a liquid composition for the preparation of pesticide concentrates containing a water insoluble dialkylene glycol diester, an organic carboxylic acid and at least one surfactant. This composition can be used to prepare formulations of pesticidal active ingredients with a concentration from 5 to 50%. The crystallization of the active ingredient is prevented by the liquid composition, whose ingredients act not only as solvents but also as crystallization inhibitors during the application of the pesticide concentrate as a diluted aqueous spray.

Description

DESCRIPTION :

LIQUID COMPOSITION FOR PESTICIDE CONCENTRATES

TECHNICAL FIELD

The present invention relates to a liquid composition for the preparation of pesticide concentrates containing, a water insoluble dialkylene glycol diester, an organic carboxylic acid and at least one surfactant. This composition can be used to prepare formulations of pesticidal active ingredients with a concentration from 5 to 50% by weight (wt), hereinafter referred to as pesticide concentrate. The crystallization of the active ingredient is prevented by the liquid composition, whose ingredients act not only as solvents but also as crystallization inhibitors during the application of the pesticide concentrate as a diluted aqueous spray. Pesticide active ingredients, according to their physical characteristics and to their intended applications, can be formulated as dusts, wettable powders, dispersible granules, suspension concentrates, emulsifiable concentrates, emulsions and concentrated solutions: as it is well known to those familiar with the art, pesticides are usually sprayed on soil or plant foliage as formulated composition in aqueous solution, suspension or emulsion which shall remain substantially stable for the time of application.

There are a lot of solid active ingredients which can be dissolved at suitable concentration range in a very polar or slightly water-soluble solvent, such as cyclohexanone, isophorone, N-methylpyrrolidone . The disadvantage of these solvents is that, when they are used as the sole dissolving agent, they can lead to crystallization of the active ingredient upon dilution of the formulation with water. In the spray equipment used for the application of aqueous formulation several filters and nozzles are present and the nozzles and filters can be blocked as a result of crystallization of active ingredients in highly diluted aqueous spray. Moreover pesticidαl concentrates can be stored for a long time before use and for this reason they must have a long term stability. BACKGROUND ART

It is well known that a lot of triazole fungicides (like azaconazole, bitertanol, bromuconazole, cyproconazole, difenoconazole, diniconazole, epoxiconazole, fenbuconazole, fluquinconazole, flusilazole, flutriafol, hexaconazole, metconazole, myclobutanil, penconazole, propiconazole, tebuconazole, tetraconazole, triadimefon, triadimenol, triticonazole), carbamate pesticides (like phenmedipham, desmedipham, bendiocarb, carbaryl, carbofuran, carbetamide, chlorpropham, fenoxycarb, formetanate, isoprocarb, methiocarb, metolcarb, pirimicarb, propham, propoxur, trimethacarb) or semicarbazone insecticides (like metaflumizone) require the use of special solvents or additives to avoid crystallization. Different formulations have been proposed in the past years as described by way of example in WO 03037084, US 5476845 US 5206225 and US 6872736. According to WO 03037084, there is provided a concentrated pesticidal solution prepared with one or more water-insoluble pesticides and lignin dissolved in a water miscible, polar solvent; US 5476845 describes a process in which a phosphoric ester is added to the spray mixture in order to prevent the clogging of the spray equipment; in US 5206225 the inventors describe N,N-dimethylalkylamides as crystallization inhibitors and solvents in formulations of triazoles; US 6872736 discloses an emulsifible concentrate of an azole derivative based on a complex mixture of one or more aliphatic alcohol alkoxylates, optionally one or more non-ionic dispersants, one or more anionic dispersants, one or more polar aprotic organic solvents, one or more non-polar organic solvents, and optionally one or more defoamers DISCLOSURE OF INVENTION We have surprisingly discovered that crystal growth inhibition of triazole fungicide, carbamate pesticides and semicarbazone insecticides in their concentrated and diluted aqueous compositions can be achieved using a composition containing a water-insoluble dialkylene glycol diester, an organic carboxylic acid and at least one surfactant. It is therefore a main object of the present invention a liquid composition comprising: i) from 10 to 60 % wt of a water insoluble dialkylene glycol diester; ii) from 1 to 25% wt of an organic carboxylic acid; iii) from 1 to 45% wt of at least one surfactant. Another object of the present invention is a pesticide concentrate containing A) from 5 to 50% wt of at lest one triazole fungicide, carbamate pesticide, semicarbazone insecticide or mixture thereof; B) from 95 to 5% wt of a liquid composition comprising i) from 10 to 60 % wt of a water-insoluble dialkylene glycol diester; ii) from 1 to 25% wt of an organic carboxylic acid; iii) from 1 to 45% wt of at least one surfactant. The water insoluble dialkylene glycol diester is a liquid compound, preferably a dialkylene glycol dibenzoate, for example diethylene glycol dibenzoate, dipropylene glycol dibenzoate or mixture thereof. These diesters can be obtained from the reaction of a carboxylic acid and a dialkylene glycol. Up to 25% wt of monoester can be present in the reaction products that can be used as such in the liquid composition of the invention.

The most preferred diester is dipropylene glycol dibenzoate. The diester is preferably present in the liquid composition in an amount ranging from 20 to 40 % wt.

Another essential ingredient of the composition of the invention is an organic carboxylic acid.

Suitable organic carboxylic acids are low molecular weight carboxylic acids, i.e. having molecular weight below 400 dalton. Preferred organic carboxylic acids are lactic acid, glycolic acid, citric acid, succinic acid, benzoic acid, fatty acids, such as oleic . acid or stearic acid, and mixture thereof.

The preferred organic carboxylic acid is a monocarboxylic acid and more preferably the acid is benzoic acid.

In order to eliminate the risk of re-crystallization of the active pesticide in concentrated form and especially upon dilution with water and during spray applications, it is of the utmost importance to introduce in the liquid composition one or more surfactants as emulsifying system. The emulsifying system of the composition of the present invention consists of at least one surfactant, which can be non-ionic, anionic, amphoteric or cationic.

Preferably the emulsifying system is a mixture of two or more surfactants of anionic and non ionic kind. Suitable non-ionic surfactants are alkoxylated derivatives of linear or branched alcohols and saturated or unsaturated fatty acids, having from 3 to 80 alkoxy groups and from 8 to 20 carbon atoms in the hydrocarbon residue; examples of such non-ionic surfactants are ethoxylated fatty acids derivatives, such as ethoxylated oleic or ethoxylated stearic acid, ethoxylated castor oil; ethoxylated sorbitan monooleate and ethoxylated sorbitan monolaurate having from 10 to 40 ethoxy groups.

Other suitable non-ionic surfactants are alkoxylated alkylphenols with from 6 to 18 carbon atoms in the alkyl residue and from 2 to 50 alkoxy groups, or alkoxylated di- or tri-arylphenol with from 3 to 30 alkoxy groups; examples of such non-ionic surfactants are 6 to 15 moles ethoxylated octyl- and nonyl-phenols.

Other appropriate non-ionic surfactants are alkyl polyglycosides, wherein the alkyl chain has from 6 to 30 carbon atoms, the saccharide residue has 5 or 6 carbon atoms and the degree of polymerization is between 1 and 7, or their ethoxylated derivatives. Anionic, amphoteric and cationic surfactants can also be used in the emulsifying system.

Suitable anionic surfactants are, by way of example, alkali, earth alkali or substituted ammonium salts of higher fatty acids (C10-C20 fatty acids), e.g. the sodium or potassium salts of oleic or stearic acid or of mixtures of natural fatty acids which are prepared, for example, from coconut or tallow oil. However, so-called synthetic surfactants are preferably used, especially alkyl sulfonates, alkyl sulfates, or alkyl aryl sulfonates. The alkyl sulfates or alkyl sulfonates are normally used as alkali, earth alkali or substituted ammonium salts and usually have an alkyl chain of 12 to 20 carbon atoms. The salts of sulfuric acid esters or phosphoric acid ester of ethoxylated fatty alcohol are also utilisable in the emulsifying system. Alkyl aryl sulfonates are, for example, the sodium, calcium or substituted ammonium salts of dodecyl benzene sulfonic acid, dibutyl naphthalene sulfonic acid or of naphthalene sulfonic acid/formaldehyde condensate.

Other suitable anionic surfactants are anionic derivatives of the alkyl polyglycosides described above, such as the tartaric, citric and sulfosuccinic esters thereof and the ether derivatives with chloroacetic acid.

The most preferred anionic surfactants are the sodium, calcium or substituted ammonium salts of dodecyl benzene sulfonic acid. Optionally the liquid composition of this invention also comprises from 0.05 to 2.0 % of a vinyl polymer, which increases the crystallization inhibition of the composition.

The vinyl polymer may be chosen among polyvinylpyrrolidone, polyvinyl acetate, copolymers of vinylpyrrolidone and vinylacetate and polyvinyl alcohols with different hydrolysis degrees. The most preferred vinyl polymer is a homopolymer of vinylpyrrolidone, but vinylpyrrolidone copolymers can also be used provided that at least 50% or more of the polymer units derive from viπylpyrrolidoπe monomer.

Polyvinylpyrrolidone polymers and vinylpyrrolidone and vinylacetate copolymers are well known commercial products; they are available in various forms, for example from the companies BASF and ISP.

Suitable polyvinylpyrrolidone polymers and copolymers to be used in the present invention may be in any of the available forms. Preferably, they have a Fikentscher K value, in the range of from 10 to 100, reflecting a molecular weight of from 5,000 to 700,000. In a preferred embodiment of the present invention, the polyvinylpyrrolidone polymer or copolymer has a Fikentscher K value of 20 to 40, especially of 25 to 35, and an average molecular weight in the range of from 10,000 to 400,000. In addition, as co-stabilizer, an acrylic copolymer obtained from polymerization of (meth)acrylic acid with an alkyl (meth)acrylate, such as methyl or ethyl (meth)acrylate, can be added to the composition of the invention at a concentration comprised between 0.1 and 2.0 % wt. Other suitable additives which can be present in the liquid composition of the invention are organic solvents, low temperature stabilizer, adhesives, antifoams.

Organic solvents which can be present in the liquid composition are, by way of example, cyclohexanone, dimethylformamide, N-methyl pyrrolidone, butyrolactone, dimethyl sulphoxide, xylene, ethanol, propanol, butanol, isophorone, lactates, methyloleate, aromatic naphtha or mixture thereof.

Low temperature stabilizer which can be added to the composition of the invention can be all those which are well known to those expert in the art. Examples of useful stabilizers are ethylene glycol, propylene glycol, glycerol and mixture thereof. The liquid composition of the invention can be used to prepare triazole fungicide, carbamate pesticide or semicarbazone insecticide concentrates.

Preferably, the pesticide is a triazole fungicide selected from tebuconazole, propiconazole, epoxiconazole, tetraconazole, metconazole, ciproconazole, amitrol, azaconazole, bitertanol, bromoconazole, difenoconazole, diniconazole, fenbuconazole, fluquinconazole, flusilazole, flutriafol, hexaconazole, imibenconazole, ipconazole, paclobutrazole, penconazole, protioconazole, simeconazole, triadimefon, triadimenol, triazamatoe or triticonazole. More preferably the pesticide is tebuconazole.

In addition to the triazole fungicides, carbamate pesticide or semicarbazone insecticides, one or more other pesticides can also be present in the pesticide concentrates of the invention. Those, which are preferably suitable in this case, are compounds having fungicidal properties. Examples of active compounds of this type which can additionally be used and mentioned are: dichlofluanid, tolylfluanid, captan, captafol, folpet, dodine, chlorothalonil, zineb, maneb, mancozeb, propineb, fenpropidin, tridemorph, aldimorph, imazalil, prochloraz, procymidone, carbendazim, benomyl, anilazine, guazatine, pencycuron.

According to a preferred embodiment, the pesticide concentrate comprises from 15 to 40% wt of pesticides. According to a particular embodiment the concentrate is a viscous liquid composition with a viscosity of 500-20,000 mPas, preferably 800 to 8,000 mPas and particularly 1000 to 4500 mPas. The viscosity of the composition can be measured using for example a Brookfield® viscosimeter with spindle 1 to 5 at 20 rpm. In this case the pesticide concentrate additionally has to contain a thickening agent, for example hydroxypropyl cellulose, precipitated or fused hydrophobized silica, gelatine, hydrophobized polysaccharides. The preferred thickening agent is hydroxypropyl cellulose. The pesticide concentrate can also be in the form of gel and can be packed into water soluble bags or sachets, which quickly dissolve when put into the water. Another object of the invention is a process for the preparation of a pesticide concentrate which comprises: a) preparing a mixture by homogenizing from 10 to 60% wt of a water insoluble dialkylene glycol diester and from 1 to 25% wt of an organic carboxylic acid at a temperature from 50 to 100 °C; b) regulating the temperature of the mixture at 45-80 °C; c) adding to the mixture from 1 to 45% wt of at least one surfactant and homogenizing; d) dissolving the triazole fungicide, carbamate pesticide, semicarbazone insecticide or mixture thereof in the resulting mixture at a temperature preferably comprised between 35 and 60°C. Further, the invention also concerns a method of combating pests at a locus which comprises treating the locus with a composition obtained by emulsifying in water a pesticide concentrate prepared according to the process of the invention. As commodities, the pesticide concentrates are in a concentrated form whereas the end-user generally employs diluted formulations. The concentrated pesticide compositions of the invention may be provided already with an amount of water up to 90% wt and can be further diluted to concentrations down to 0.001% of active ingredient by the final user. The application doses usually are in the range of about 0.01 to 10 kg a.i./ha. To prepare the ready to use aqueous spray the liquid compositions are mixed with the desired amount of water with stirring or pumping in order to distribute it uniformly and in finely dispersed form. The following examples are for the purpose of illustrating the preparation and the crystallization behaviour of the pesticide concentrates, which can be prepared according to the invention. EXAMPLES

Example 1

Preparation of a liquid composition according to the invention.

For the preparation of the composition (whose recipe is reported in

Table 1 ), dipropylene glycol dibenzoate and benzoic acid were mixed and vigorously stirred at a temperature of 90 °C to give a homogeneous liquid. The blend was then cooled at a temperature of

70 °C and the other components were added and dissolved by stirring.

Table 1

Example 2

Preparation of pesticide concentrates according to the invention.

The liquid composition described in Example 1 was used for the preparation of different pesticide concentrates by simply adding the pesticide and mixing vigorously at a temperature of 50 °C.

The following pesticide concentrates were prepared: a) Tebuconazole 200 g/l

Tebuconazole 95% 210.Og

Liquid composition from Ex. 1 880.0 g b) Tebuconαzole 250q/L

Tebuconαzole 95% 263.Og

Liquid composition from Ex. 1 830.Og

c) Tebuconαzole 300q/L

Tebuconαzole 95% 316.Og

Liquid composition from Ex. 1 774.0 g

d) Tebuconαzole 100 g/L+ Cαrbendαzim 200q/L

Tebuconαzole 105.Og

Cαrbendαzim 210.Og

Liquid composition from Ex. 1 450.Og

Ethoxylαted Tristyrylphenol 100.0 g Water to 100O mL

e) Propiconazole 1 25g/L + Trifloxistrobin 125g/L Propiconazole 125.Og

Trifloxistrobin 125.Og Liquid composition from Ex. 1 to 1000 mL

The pesticide concentrates a) - e) were stored at controlled temperature in order to evaluate their stability over the time. Acelerated aging stability test at temperature of 5°C and 54 °C have been carried out, the results are reported in Table 2. Table 2

OK = no crystallization, na = not available

Example 3

Preparation of the diluted aqueous composition of the pesticide concentrates.

Diluted aqueous pesticide compositions which contain the pesticide concentrates a) - b) at a concentration of 1.0 % wt were prepared by mixing the pesticide concentrates with CIPAC standard waters 20 and

342 (CIPAC MT18).

Stability test at temperature of 30 °C have been carried out on the thus obtained diluted aqueous pesticide compositions; the results are reported in Table 3. Table 3

^* Test of the "Associagao Brasileira de Normas Tecnica" (ABNT)

OK = Stable Composition

Example 4

Crystallization test.

Diluted aqueous pesticide compositions which contain the pesticide concentrates a) - c} at a concentration of 0.2 % wt were prepared by mixing the pesticide concentrates with CIPAC standard waters 20

(CIPAC MT18).

Stability test at temperature of O ⁰C have been carried out on the thus obtained diluted aqueous pesticide compositions; the results are reported in Table 4.

Table 4

OK= No Crystallization

Claims

1. Liquid composition useful for the preparation of pesticide concentrates comprising : i) from 10 to 60 % wt of a water- insoluble dialkylene glycol diester; ii) from 1 to 25 % wt of an organic carboxylic acid; iii) from 1 to 45 % wt of at least one surfactant.

2. Liquid composition of Claim 1 , wherein the water-insoluble dialkylene glycol diester is diethylene glycol dibenzoate, dipropylene glycol dibenzoate, or mixture thereof.

3. Liquid composition of Claim 2, wherein the water-insoluble dialkylene glycol diester is dipropylene glycol dibenzoate.

4. Liquid composition of Claim 2 wherein the diester is present in an amount ranging from 20 to 40 % wt.

5. Liquid composition of any of Claims from 1 to 4, wherein the organic carboxylic acid is lactic acid, glycolic acid, citric acid, succinic acid, benzoic acid, a fatty acid, such as oleic acid or stearic acid, or mixture thereof.

6. Liquid composition of Claim 5, wherein the organic carboxylic acid is benzoic acid.

7. Liquid composition of Claim 1 , comprising iii) from 1 to 45 % wt of a mixture of two or more surfactants of anionic and non ionic kind.

8. Liquid composition of any of Claims from 1 to 7, comprising from 0.05 to 2.0% wt of a vinyl polymer chosen among polyvinylpyrrolidone, polyvinyl acetate, copolymers of polyvinylpyrrolidone/polyvinyl acetate and polyvinyl alcohols with different hydrolysis degrees.

9. Liquid composition of Claim 8 further comprising between 0.1 and 2.0% wt of an acrylic copolymer obtained from polymerization of (meth)acrylic acid with an alkyl (meth)acrylate.

10. Pesticide concentrates which contain A) from 5 to 50% wt of at least one triazole fungicide, carbamate pesticide, semicarbazone insecticide or mixture thereof; B) from 95 to 5% wt of the liquid composition of comprising i) from 10 to 60% wt of a water insoluble dialkylene glycol diester; ii) from 1 to 25% wt of an organic carboxylic acid; iii) from 1 to 45% wt of at least one surfactant.

1 1 . Pesticide concentrates of Claim 10, wherein the pesticide is a triazole fungicide selected from tebuconazole, propiconazole, epoxiconazole, tetraconazole, metconazole, ciproconazole, amitrol, azaconazole, bitertanol, bromoconazole, difenoconazole, diniconazole, fenbuconazole, fluquinconazole, flusilazole, flutriafol, hexaconazole, imibenconazole, ipconazole, paclobutrazole, penconazole, protioconazole, simeconazole, triadimefon, triadimenol, triazamatoe and triticonazole.

12. Pesticide concentrates of Claim U , wherein the triazole fungicide is tebuconazole.

13. Pesticide concentrates of any of Claims from 10 to 12 with a water content of from 10 to 95% wt.

14. Process for the preparation of a pesticide concentrate which comprises: a) preparing a mixture by homogenizing from 10 to 60% wt of a water insoluble dialkylene glycol diester and from 1 to 25% wt of a organic carboxylic acid at a temperature from 50 to 100 °C; b) regulating the temperature of the mixture at 45-80 °C; c) adding to the mixture from 1 to 45% wt of at least one surfactant and homogenizing; d) dissolving the triazole fungicide, carbamate pesticide, semicarbazone insecticide or mixture thereof in the resulting mixture.