Micro-emulsions.

The present invention relates to aqueous microemulsions of agrochemical active substances, active substances for controlling pests in the household and hygiene sector and / or pharmacologically active substances. The invention also relates to a method for producing these microemulsions and their use.

Oil-in-water emulsions of numerous water-insoluble agrochemical active substances are already known, which in addition to the active substances each contain either a surface-active substance and a thickener or a relatively large amount of surface-active substances (cf. DE-A 30 09 944, DE-A 30 11 611 and JP-A 122 628-77). This addition of thickener or Large amounts of surfactant are associated with additional costs and thus represent a serious disadvantage of the known oil-in-water emulsions. In addition, the preparation of such emulsions described so far is not generally applicable. In essence, only those substances which are sparingly soluble in water can be emulsified if they are liquid at room temperature or at least have a very low melting point. Another disadvantage is that the known oil-in-water emulsions are often not sufficiently stable to cold and that in some cases forced emulsification with the aid of homogenizers is necessary.

Aqueous microemulsions have now been found which<ul id="ul0001" list-style="none"><li>0.1 to 80% by weight of at least one agrochemically active substance which is sparingly soluble in water, an active substance for controlling pests in the household and hygiene sector and / or a pharmacologically active substance,</li><li>- 1 to 20 wt .-% of an emulsifier mixture<ul id="ul0002" list-style="none"><li>a) at least one alkylaryl polyglycol ether of the formula<chemistry id="chem0001" num="0001"><img file="EP0107009A2_D0001.tif" /></chemistry>in which R represents alkyl having 8 to 20 carbon atoms, X and Y each represent a -CH₂-CH₂-0-, -CH₂-CH-O- or -CH-CH₂-O group CH₃^CH₃ but where X and Y are not simultaneously an oxyethylene or oxypropylene unit, m is a number from 10 to 45 and n is a number from 10 to 45, and at least one alkylarylsulfonic acid salt of the formula<chemistry id="chem0002" num="0002"><img file="EP0107009A2_D0002.tif" /></chemistry>in which R¹ represents alkyl with 8 to 35 carbon atoms and Me^⊕ for an alkali metal cation, an equivalent of an alkaline earth metal cation or for a cation of the formula<chemistry id="chem0003" num="0003"><img file="EP0107009A2_D0003.tif" /></chemistry> stands in what _R', R ", R"' and R^IV independently of one another represent hydrogen, alkyl having 1 to 4 carbon atoms or hydroxyalkyl having 1 to 4 carbon atoms, or</li><li>b) at least one alkylaryl polyglycol ether of the formula<chemistry id="chem0004" num="0004"><img file="EP0107009A2_D0004.tif" /></chemistry>in which p stands for numbers from 5 to 20 and q stands for numbers from 1 to 3, and at least one alkylarylsulfonic acid salt of the formula<chemistry id="chem0005" num="0005"><img file="EP0107009A2_D0005.tif" /></chemistry>in which _R¹ and me^⊕ have the meaning given above,</li></ul></li><li>- as well as water and</li><li>- optionally 1 to 30% by weight of at least one water-immiscible organic solvent and / or a solubilizer and</li><li>- optionally contain 0.05 to 15% by weight of additives, the sum of the components in each case being 100% by weight. Furthermore, it has been found that the microemulsions according to the invention can be prepared by preparing a homogeneous mixture</li><li>at least one agrochemical active ingredient which is sparingly soluble in water, an active ingredient for combating pests in the household and hygiene sector and / or a pharmacologically active substance,</li><li>- An emulsifier mixture<ul id="ul0003" list-style="none"><li>a) at least one alkylaryl polyglycol ether of the formula<chemistry id="chem0006" num="0006"><img file="EP0107009A2_D0006.tif" /></chemistry> in which R, X, Y, m and n have the meaning given above, and at least one alkylarylsulfonic acid salt of the formula<chemistry id="chem0007" num="0007"><img file="EP0107009A2_D0007.tif" /></chemistry>in which R and Me^⊕ have the meaning given above, or</li><li>b) at least one alkylaryl polyglycol ether of the formula<chemistry id="chem0008" num="0008"><img file="EP0107009A2_D0008.tif" /></chemistry>in which p and q have the meaning given above, and at least one alkylaryl-sulfonic acid salt of the formula<chemistry id="chem0009" num="0009"><img file="EP0107009A2_D0009.tif" /></chemistry>in which R and Me^⊕ have the meaning given above,</li></ul></li><li>- optionally at least one water-immiscible organic solvent and / or a solubilizer and</li><li>- if necessary, additives with stirring in water containing additives.</li></ul>

Finally, it was found that the microemulsions according to the invention, depending on the active ingredients they contain, can be used for various purposes in agriculture and horticulture, in the household and hygiene sector or in the medical field.

It is extremely surprising that the microemulsions according to the invention are stable, because it was to be expected from the known state of the art that such emulsions, which have no thickening agents and even a low proportion of surfactants, cannot be kept for a long time. It is apparent from DE-A 30 09 944 and DE-A 30 11 611 that the oil-in-water emulsions described therein contain a thickener as a stabilizer. The emulsions disclosed in JP-A 122 628-77 have a very high proportion of surfactant in relation to the amount of active ingredient. The excellent stability of the microemulsions according to the invention could therefore not be foreseen.

The microemulsions according to the invention are notable for a number of advantages. This eliminates the need for costly additions of thickeners or large quantities of emulsifiers. Furthermore, these emulsions either contain no or only an extremely small amount of organic solvents. They are therefore non-flammable, free or at least almost free from odors caused by organic solvents and have a lower toxicity or Phytotoxicity as corresponding formulations that contain organic solvents in the usual concentrations. In addition, the microemulsions according to the invention are stable under the conditions prevailing in practice. In long-term storage, these emulsions remain unchanged both at temperatures of 50 ° C and at low temperatures. Finally, the microemulsions according to the invention can be produced in a simple manner. Forced emulsification with the help of homogenizers is not necessary. In addition, there is a very considerable advantage that solid or liquid active ingredients which are sparingly soluble in water can be emulsified equally well at room temperature. Furthermore, the microemulsions according to the invention have a relatively low viscosity, so that precise metering presents no difficulties. Finally, the microemulsions according to the invention are completely transparent preparations, which can be diluted with water in any ratio before use without any problem, resulting in stable, sprayable formulations.

The microemulsions according to the invention contain at least one agrochemically active ingredient which is sparingly soluble in water, an active ingredient for combating pests in the household and hygiene sector and / or a pharmacologically active substance. These active substances are in the oil phase in the liquid state.

Both substances that are liquid at room temperature and those that are solid at room temperature are suitable as active substances. The only requirement for liquid active ingredients is that they are sparingly soluble in water. Substances of this type are to be understood here as substances which are soluble in water at 20 ° C. to a maximum of 0.5% by weight. However, solid active ingredients must also be sufficiently soluble in an organic solvent which is not very miscible with water and / or a solubilizer.

In the present case, agrochemical substances are understood to mean all active substances which can normally be used in crop protection. These include, for example, insecticides, acaricides, nematicides, fungicides, herbicides, growth regulators and fertilizers. Examples of such active ingredients are:<ul id="ul0004" list-style="none"><li>O, O-Diethyl-O- (4-nitro-phenyl) thionophosphoric acid ester 0.0-Dimethyl-0- (4-nitro-phenyl) thionophosphoric acid ester</li><li>O- (ethyl) -O- (4-methylthio-phenyl) -S-propyl-dithiophosphate</li><li>(O, O-diethylthionophosphoryl) -α-oximino-phenylacetic acid nitrile</li><li>2-isopropoxy-phenyl-N-methylcarbamate 3-methylthio-4-amino-6-tert-butyl-1,2,4-triazin-5-one 3-methylthio-4-isobutylidenamino-6-tert-butyl- 1,2,4-triazin-5-one</li><li>2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-methyl-carbamate</li><li>3,5-dimethyl-4-methylthiophenyl-N-methyl-carbamate 0.0-diethyl-0- (3-chloro-4-methyl-7-coumarinyl) thiophosphate</li><li>6,7,8,9,10,10-hexachloro-1,5,5A, 6,9,9A-hexahydro-6,9-methane-2,3,4-benzo-dioxathiepin-3-oxide</li><li>1,4,5,6,7,8,8-heptachlor-4,7-endo-methylene-3A, 4,7,7A-tetrahydroinden 2- (2-furyl) benzimidazole</li><li>5-amino-1-bis (dimethylamido) phosphoryl-3-phenyl-1,2,4-triazole</li><li>4-Hydroxy-3- (1,2,3,4-tetrahydro-1-naphthyl) coumarin S- [1,2-bis (ethoxycarbonyl) ethyl] -O, O-dimethyldithiophosphoric acid ester</li><li>O, O-dimethyl-O- (4-methylmercapto-3-methylphenyl) thionophosphoric acid ester</li><li>O-ethyl-O- (2-isospropyloxycarbonyl-phenyl) -N-isopropyl-thionophosphoric acid ester amide</li><li>1- (4-chlorophenoxy) -3,3-dimethyl-1- (1,2,4-triazol-1-yl) -2-butanone</li><li>(S) -α-cyano-3-phenoxybenzyl (1R) -cis-3- (2,2-dibromovinyl) -2,2-dimethylcyclopropane carboxylate</li><li>2,2-Dimethyl-3- (ß, ß-dichlorovinyl) -cyclopropanecarboxylic acid-α-cyano-3-phenoxy-4-fluoro-benzyl ester.</li></ul>

In the present case, active substances for controlling pests in the household and hygiene sector are to be understood as all active substances which are poorly soluble in water for such indications. Examples of such active ingredients are:<ul id="ul0005" list-style="none"><li>2-isopropoxy-phenyl-N-methyl carbamate</li><li>0.0-Diethyl-0- (4-nitro-phenyl) thionophosphoric acid ester</li><li>O, O-dimethyl-O- (4-nitro-phenyl) thionophosphoric acid ester S- [1,2-bis (ethoxycarbonyl) ethyl] -O, O-dimethyl-dithiophosphoric acid ester</li><li>0.0-Dimethyl-0- (3-methyl-4-nitro-phenyl) thionophosphoric acid ester</li><li>0.0-Dimethyl-0- (4-methylmercapto-3-methylphenyl) thionophosphoric acid ester</li><li>δ-hexachlorocyclohexane (cyclohex-1-ene-1,2-dicarboximidomethyl) -2,2-dimethyl-3- (2-methylpropenyl) cyclopropane carboxylate</li></ul>

In the present case, pharmacologically active substances are to be understood as substances which are preferably insoluble in water and can be used in the veterinary field. An example of such active ingredients is:<ul id="ul0006" list-style="none"><li>2,2-Dimethyl-3- [β- (p-chlorophenyl) -β-chlorovinyl] -cyclopropanecarboxylic acid-α-cyano-3-phenoxy-4-fluoro-benzyl ester.</li></ul>

The emulsifier mixtures contained in the microemulsions according to the invention consist either of at least one alkylaryl polyglycol ether of the formula (I) and at least one alkylarylsulfonic acid salt of the formula (II) or of at least one alkylaryl polyglycol ether of the formula (III) and at least one alkylarylsulfonic acid Salt of the formula (II).

The aikylaryl polyglycol ethers of the formula (I) are generally defined by the formula given. In this formula, R preferably represents alkyl having 10 to 18 carbon atoms. X and Y each represent a -CH₂-CH₂-⁰-, <chemistry id="chem0010" num="0010"><img file="EP0107009A2_D0010.tif" /></chemistry>however, X and Y do not simultaneously represent an oxyethylene or oxypropylene unit. The index m preferably stands for numbers from 12 to 30, and the index n preferably stands for numbers from 12 to 40. The numbers for the indices m and n represent average values.

The emulsifiers of this type used in practice are generally mixtures of several compounds of the formula (I). In particular, these are mixtures of substances of the formula (I) which differ in the number of oxyethylene or oxypropylene units. As a result, fractional numbers are also calculated as mean values ​​for the indices m and n. Examples include substances for which the following average compositions result:<chemistry id="chem0011" num="0011"><img file="EP0107009A2_D0011.tif" /></chemistry><chemistry id="chem0012" num="0012"><img file="EP0107009A2_D0012.tif" /></chemistry><chemistry id="chem0013" num="0013"><img file="EP0107009A2_D0013.tif" /></chemistry><chemistry id="chem0014" num="0014"><img file="EP0107009A2_D0014.tif" /></chemistry><chemistry id="chem0015" num="0015"><img file="EP0107009A2_D0015.tif" /></chemistry><chemistry id="chem0016" num="0016"><img file="EP0107009A2_D0016.tif" /></chemistry>

The alkylaryl polyglycol ethers of the formula (I) are known.

The alkylaryl-sulfonic acid salts contained in the microemulsions according to the invention are generally defined by the formula (II). In this formula, R preferably represents straight-chain or branched alkyl having 9 to 30 carbon atoms. Me^⊕ preferably represents a sodium cation, an equivalent of a calcium cation or a cation of the formula<chemistry id="chem0017" num="0017"><img file="EP0107009A2_D0017.tif" /></chemistry> wherein<ul id="ul0007" list-style="none"><li>_{R '}, _R", _R"'and R^IV independently of one another are preferably hydrogen, alkyl having 1 or 2 carbon atoms or hydroxyalkyl having 1 to 2 carbon atoms.</li></ul>

The following may be mentioned as examples of alkylaryl-sulfonic acid salts of the formula (II):<ul id="ul0008" list-style="none"><li>4- (n-Nonyl) phenyl sulfonic acid sodium salt</li><li>4- (n-dodecyl) phenyl sulfonic acid calcium salt</li><li>4- (Tetrapropylene) phenyl sulfonic acid sodium salt</li><li>4- (n-nonyl) phenyl sulfonic acid calcium salt</li><li>4- (i-dodecyl) phenyl sulfonic acid ammonium salt</li><li>4- (n-dodecyl) phenyl sulfonic acid (2-hydroxyethyl) ammonium salt.</li></ul>

The alkylaryl sulfonic acid salts of the formula (II) are known. They are generally used as 50-75% solutions in organic solvents, for example n- or i-butanol or benzyl alcohol, but can in principle also be used without a solvent.

The alkylaryl polyglycol ethers of the formula (III) are generally defined by the formula given. In this formula, the index p preferably represents numbers from 8 to 18, and the index q preferably represents numbers from 1 to 2. The numbers for the indices p and q represent average values.

The emulsifiers of this type used in practice are generally mixtures of several compounds of the formula (III). In particular, these are mixtures of substances of the formula (III) which differ in the number of oxyethylene units or in the degree of substitution on the phenyl radical. This means that fractional numbers can also be calculated as averages for the indices p and q. Examples include substances for which the following average compositions result:<chemistry id="chem0018" num="0018"><img file="EP0107009A2_D0018.tif" /></chemistry>and<chemistry id="chem0019" num="0019"><img file="EP0107009A2_D0019.tif" /></chemistry>

The alkylaryl polyglycol ethers of the formula (III) are also known.

Suitable organic solvents, which may be present in the microemulsions according to the invention, are all customary organic solvents which are not very miscible with water. Aromatic hydrocarbons such as xylene, toluene and dimethylnaphthalene, chlorinated aromatic hydrocarbons such as chlorobenzenes, furthermore aliphatic hydrocarbons such as petrol and petroleum ether, furthermore halogenated aliphatic hydrocarbons such as methylene chloride and chloroform and also cycloaliphatic hydrocarbons such as cyclohexane also alcohols and ketones, such as n-butanol, n-hexanol, iso-hexanol, n-octanol, cyclohexanol, Benzyl alcohol, di-n-butyl ketone and isophorone, and further ethers and esters, such as glycol monomethyl ether and glycol monomethyl ether acetate and also also triethyl phosphate.

Suitable solubilizers which can be present in the microemulsions according to the invention are all customary solubilizers. Alkylphenols or cresols which are condensed per mole with 1 to 8 moles of ethylene oxide can preferably be used. In this context, special mention should be made of p-cresol which is condensed with 1 to 8 moles of ethylene oxide per mole.

Preservatives, dyes, cold stabilizers and synergists are suitable as additives which may be present in the microemulsions according to the invention.

Examples of preservatives are 2-hydroxybiphenyl and sorbic acid. Examples of dyes are azo dyes and phthalocyanine dyes. Examples of cold stabilizers are urea, sugar and salts such as ammonium sulfate and sodium oleate. An example of a synergist is 3,4-methylenedioxy-6-propyl-benzyl-n-butyl-diethylene glycol ether (piperonyl butoxide).

In the microemulsions according to the invention, the percentages of the components contained can be varied within certain ranges. The proportion of active ingredient or active ingredients is generally between 0.1 and 80% by weight, preferably between 5 and 80% by weight. The proportion of emulsifier mixture is generally 1 to 20% by weight, preferably 3 to 16% by weight, the ratio of the emulsifiers to one another also being able to be varied within a certain range. In general, 0.2 to 1.2, preferably 0.4 to 1 part of emulsifier of the formula (II) is present in 1 part of the emulsifier of the formula (I). Furthermore, 1 part of the emulsifier of the formula (III) generally comprises 0.1 to 1.2 parts, preferably 0.2 to 1.0 part, of emulsifier of the formula (II).

Organic solvents and / or solubilizers which are not very miscible with water can be present in proportions of 1 to 30% by weight, preferably 5 to 20% by weight. Additives can be contained in proportions of 0.05 to 15% by weight, preferably 0.1 to 10% by weight. The percentage of water in the microemulsions according to the invention is in each case calculated as the difference from 100% by weight and the sum of the percentage of the other components.

In the microemulsions according to the invention, the ratio of active ingredient (s), if appropriate in a mixture with organic solvents and / or solubilizers on the one hand, to the emulsifier mixture on the other hand can be varied within a certain range. 1 part to 15 parts by weight, preferably 2 to 10 parts by weight of active ingredient (s), if appropriate in a mixture with organic solvents and / or solubilizers, are generally present in 1 part of the emulsifier mixture.

In the preparation of the microemulsions according to the invention, it is preferably possible to use all those components which have already been mentioned in connection with the description of the microemulsions according to the invention.

If an active ingredient is used in the process according to the invention which is in the liquid state at temperatures up to 40 ° C., the addition of an organic solvent which is not very miscible with water and / or a solubilizer is generally unnecessary.

If, on the other hand, an active substance is used in the process according to the invention which is in the solid state at temperatures up to 40 ° C., it is necessary to dissolve the active substance in question in an organic solvent and / or solubilizer which is not very miscible with water before the emulsification. The amount of organic solvent and / or solubilizer is measured so that it is just sufficient to dissolve the solid substance. The reaction temperatures can be varied within a substantial range in the process according to the invention. In general, temperatures between 10 ° C and 80 ° C, preferably between 20 ° C and 60 ° C.

When carrying out the process according to the invention, the procedure is generally such that a homogeneous solution of one or more active ingredients, an emulsifier mixture, if appropriate an organic solvent and / or solubilizer which is not readily miscible with water, and, if appropriate, additives are prepared, and this mixture is then stirred, if appropriate Water containing additives there. The amounts of the components are chosen so that the components are present in the resulting microemulsion in the concentration desired in each case. The order in which the components of the organic phase are combined is variable. The organic phase is expediently added to the aqueous phase slowly with uniform stirring using conventional stirrers. This forms a fine-particle, transparent microemulsion that no longer differs optically from a solution.

The microemulsions according to the invention can be applied either in the prepared form or after prior dilution . The application rate depends on the concentration of the active ingredients in the microemulsion and on the respective indication.

The microemulsions according to the invention are used by the customary methods, for example by spraying, spraying or pouring.

The preparation of the microemulsions according to the invention can be seen from the following examples.

Manufacturing examples

example 1

70 g of the insecticidal active ingredient O, O-dimethyl-O- (4-methylmercapto-3-methylphenyl) thionophosphoric acid ester are mixed with stirring at temperatures between 20 ° C. and 40 ° C. with 8 g of an emulsifier mixture which<ul id="ul0009" list-style="none"><li>6 parts by weight of a nonylphenol polyglycol ether which has an average of 27 oxyethylene and 27 oxypropylene units per molecule,</li><li>and</li><li>- 4 parts by weight of the 4- (n-dodecyl) phenyl sulfonic acid calcium salt (dissolved in n-butanol)</li></ul>consists. The resulting homogeneous solution is poured into 22 g of demineralized water with intensive stirring within 2 minutes. After the addition is complete, stirring is continued for 5 minutes. A transparent microemulsion is formed, which shows no physical or chemical changes even after weeks of storage at elevated temperature.

Example 2

50 g of O, O-dimethyl-O- (4-methylmercapto-3-methylphenyl) thionophosphoric acid ester are mixed with stirring at temperatures between 20 and 40 ° C with 14 g of an emulsifier mixture<ul id="ul0010" list-style="none"><li>- 10 parts by weight of an alkylaryl polyglycol ether, the average composition of which follows from the following formula<chemistry id="chem0020" num="0020"><img file="EP0107009A2_D0020.tif" /></chemistry></li><li>and</li><li>- 4 parts by weight of the 4- (n-dodecyl) phenyl sulfonic acid calcium salt (dissolved in n-butanol)</li></ul>consists. The resulting homogeneous solution is poured into 36 g of demineralized water with intensive stirring within 2 minutes. After the addition is complete, stirring is continued for 5 minutes. A transparent microemulsion is formed, which shows no physical or chemical changes even after weeks of storage at elevated temperature.