FI65010C - HERBICIDISKT VERKSAMMA FENOXIALKANKARBOXYLSYRAESTRARS LAGERSTABILA KONCENTRERADE EMULSION OCH DESS FRAMSTAELLNINGSFOERFARANDE - Google Patents

Description

χ 6501 0

A durable, concentrated emulsion for storing herbicidally active phenoxyalkanecarboxylic acid esters and a process for its preparation. ~ Herbieidiskt verksanma fenoxyialkankarboxyl-syraestrars lagerstabila, koneentrerade emulsion och dess framställningsförfarande.

The present invention relates to an aqueous, storage-stable, concentrated emulsion of one or more herbicidally active phenoxyalkanecarboxylic acid esters and to a process for their preparation.

Phenoxyalkanecarboxylic acids are among the most common Herbicides. They are used as their amine melts, mineral salts or also as esters thereof, e.g. as isopropyl, butyl, butyl glycol or 2-ethylhexyl esters. The advantage of the ester is that it penetrates plants faster and thus its use is less dependent on the weather. Their solubility in water is low, but they are still soluble in oils such as diesel oil, fuel oil, petroleum ether, xylenes, cyclohexanone, isophorone, or highly purified hydrocarbons. Usually, the ester is dissolved in such a solvent, an emulsifier is added to the solvent to form a concentrated, clear, emulsifiable solution (emulsion concentrate, EC), which is diluted for use in the field with water to form an oil-in-water emulsion.

According to AT-PS 307 802, it is also possible to prepare an oil-in-water high-viscosity formulation consisting of the active ingredient, mineral oil, water and formulation auxiliaries for the storage of pesticides. This formulation is inverted for application shortly before use with an additive consisting of a solvent and a dispersant into a readily flowing water-in-oil dispersion: "Inverse Emulsion".

However, both formulation methods, both the commonly used emulsion concentrate and the high viscosity dispersion, have significant disadvantages due to the solvent used. All solvents commonly used in them, like most organic solvents, are at least hazardous to health and, above all, flammable. Thus, highly purified, predominantly aliphatic hydrocarbons have a flash point of 40-80 ° C, an isophorone has a flash point of 93 ° C, cyclohexanone has a flash point of 44 ° C, and the most commonly used xylene has a flash point of only about 25 ° C.

Emulsion concentrates prepared with these solvents are thus also flammable, and to date there have been several cases of storage depots at both the manufacturer and the user.

On the other hand, it has now been found that with the use of certain excipients it is possible to prepare a storage-resistant, high-concentration emulsion of herbicidal esters which is made on an aqueous basis and which is therefore non-combustible and which is not harmful to health due to the solvent. The fact that the aqueous medium can be used to prepare storage emulsions resistant to the storage of phenoxy esters is surprising, since the phenoxy esters themselves are soluble, albeit to a small extent, in water and can thus be saponified.

The present invention therefore relates to an aqueous, storage-stable, concentrated emulsion of one or more herbicidally active phenoxyalkanecarboxylic acid esters using an oil-soluble emulsifier and a water-soluble dispersant, characterized in that it contains one or more ester-soluble emulsifiers. per 100 parts of an ester having an HLB value of 9 to 16 and selected from the group consisting of a fatty acid polyethylene glycol ester, a polyethylene glycol ether of fatty alcohols, glycerides or alkylphenols, polyoxyethylene and polyol ethylene glycol ethylene glycol ethylene glycol ethylene glycol polyethylene glycol mixtures of a polyene glycol block polymer with alkylarylsulfonates, and one or more ionic and nonionic 3,65010 water-soluble dispersants from the group consisting of phosphated alkylaryl polyethylene oxide and ethylene oxide condensates with a fatty amine, optionally in combination with conventional antifreeze agents and / or conventional antifoams, the active emulsion having an active ingredient content of 30 to 75% by weight, a viscosity of 50 to 3000 mPa.s, a droplet size of 1.5 and pH 4-10.

The highly concentrated emulsion according to the invention is prepared by mixing the individual reaction components or by mixing two solutions: Solution I contains a phenoxy ester or esters and an ester-soluble emulsifier, Solution II contains a dispersant dissolved in water and optionally an antifreeze, thickener or antifoam.

Phenoxyester soluble or fat soluble emulsifiers cause the active ingredient to distribute into the outer phase. Examples of such emulsifiers having an HLB ("hydrophil - lipo-Phil - balance") value of 9 to 16 are: Polyethylene glycol fatty acid polyol ester, polyethylene glycol ether of fatty alcohols, mono- or diglycerides and alkylphenols, further polyethylene glycol-polypropylene -segmenttipolymeerit. The emulsifiers can be used alone, in admixture with one another or in admixture with the ammonium, Ca, Mg, K, Na and Zn salts of alkyl (C8-C18) benzenesulfonic acids. Fatty acid polyethylene glycol ester or polyoxyethylene-polyoxypropylene are particularly suitable. block polymers with alkylaryl sulfonates.

Solution I has a concentration of fat-soluble emulsifiers of 1 to 10 parts by weight, which is 1.01 to 11.1 parts by weight of emulsifier per 100 parts by weight of ester. In this case, a range of 2 to 4 parts by weight per 100 parts of solution I is considered particularly good. The concentrated, storage-resistant emulsion usually contains 0.5 to 5% by weight, in particular 1 to 2% by weight, of emulsifiers.

The water-soluble dispersant stabilizes the distribution of the inner phase, e.g., by electrostatically charging the particles or by other repulsive forces, e.g., by an etheric blocking effect. It can also be ionic or non-ionic, but most preferably anionic and high molecular weight. Examples of water-soluble ionic dispersants are: Phosphated alkylaryl polyethylene oxide, in particular phosphorylated nonylphenyl polyethylene oxide having 2 to 20 moles of ethylene oxide in the ethylene oxide moiety, or salts thereof. Other examples are the ammonium, Na, K salts of phosphorylated polystyrene-phenylphenyl polyethylene oxide. Examples of non-ionic dispersants are ethylene oxide condensates with a fatty amine. Particularly suitable dispersants are phosphoted alkylaryl polyethylene oxides.

Solution II usually contains 0.5 to 5 parts by weight of a water-soluble dispersant, with a range of 1 to 3 parts by weight per 100 parts of solution II being particularly preferred. The concentration of dispersant in the concentrated, storage-stable emulsion is mostly 0.2-4% by weight, preferably 0.4-2% by weight.

Storage-resistant emulsions are usually prepared by first preparing an aqueous solution II of a dispersant containing any antifreeze, antifoam or thickeners, and mixing it as a solution I with a liquid phenoxy ester or ester containing the emulsifier dissolved to form a homogeneous mixture. This mixing takes place with devices that generate a shear rate of 2 4-1 emulsion between 10 and 10 s. At high viscosity (3000 mPa) this corresponds to the shear stress 2 4 3. 10 - 3. 10 Pa, suitable for devices such as Homorex and Ultra-Turrax. At low viscosity (5 mPa), this corresponds to shear stresses of 5 to 500 Pa, which are suitable for devices such as vibrators, low-speed mixers, circulation pumps and similar devices. Since the viscosity decreases with increasing temperature, it is also possible to use lower speed devices when higher temperatures are used, about 50-90 ° C. In this case, a homogeneous droplet distribution must be formed so that the droplet sizes are 1-5 [mu] m, preferably 2-3 [mu] m, in which case, in addition to the size of the individual droplets, it is important to have the narrowest possible distribution at low emulsion viscosity.

The viscosity of the concentrated emulsion is an essential factor for storage stability. The higher the viscosity the better the storage stability. On the other hand, however, too high a viscosity in use is unfavorable in terms of dilutability with water and spontaneous dispersibility. By means of the concentrated emulsion prepared according to the invention, it is possible to prepare preparations with a viscosity in the range from 50 to 3000 mPa which are stable and at the same time easily dilutable. On the one hand, in terms of dilutability and spontaneous dispersibility, on the other hand, the best results are obtained with viscosities between 500 and 1500 mPa.s.

Adjustment of the pH is still essential for the preparation of a stable emulsion. For each combination of active ingredient, emulsifier and dispersant, there is an optimal pH at which the emulsion is most stable. This physical stability is in the alkaline range, however, pH values above 10 should be avoided, as partial saponification of the ester may already begin in this range upon prolonged storage and at elevated temperatures. In the acidic range, pH values below 3 must be avoided, as fusion can occur in this range during long-term storage, i.e. the emulsion becomes more and more physically unstable. A pH range of 6.5 to 9, especially 7.5 to 8.5, is preferred.

For the preparation of the substance according to the invention, all herbicidally active phenoxyalkanecarboxylic acid esters are suitable, alone or in admixture with one another, in particular esters with an alcohol chain length of -Cg, such as, for example, octyl esters of CMPP, MCPA or 2,4,5-T acids.

Since the technical phenoxyalkanoic acid esters, due to their methods of preparation, usually have a pH of about 3 (measured as a 10% aqueous dispersion), the desired pH is adjusted with a conventional lye, e.g. sodium hydroxide or potassium hydroxide. The desired pH can be adjusted either during or after emulsion preparation. However, it is also possible to use purified, "neutral" esters, in which case it is not necessary to readjust the pH.

Conventional antifreeze agents such as ethylene glycol, glycerin, urea, glycol ether or other alcohols may be added to the emulsions to provide adequate cold resistance. It is further possible to add known inorganic or organic thickeners, such as xanthan gum, sodium polyacrylate, carboxymethylcellulose, colloidal silicic acid or swelling clay minerals such as bentonite, to control a certain viscosity. To reduce foaming, antifoaming agents such as long chain alcohols, 2-ethylhexanol or cetyl alcohol, high polymeric glycols and above all silicones can be added.

For field use, the concentrated emulsions prepared according to the invention are completely diluted with water in the same way as the hitherto conventional combustible emulsion concentrates and can be applied by the same spraying devices.

The following examples illustrate the preparation of the substance of the invention as well as its chemical and physical stability. The technical phenoxyalkanecarboxylic acid esters used comply with the guidelines recommended by the WHO. Stability was examined in a storage experiment in which the temperature varied between -10 ° C and + 50 ° C over 24 hours. After four weeks of storage, the following were measured: 1. Change in pH 2. Consumption of 0.01 N sodium hydroxide solution required to readjust the initial pH 3. Change in viscosity (measured with a Brookfield LVT viscometer, spindle 2, 6 rpm) min in Examples 3, 13, 17, 18 with spindle 1, 6 rpm) 7 65010 4. Change in 0.01% emulsion turbidity value correlated with droplet size change (measured with a Lang opacimeter in 100 ml cuvettes) 5. Percentage of supernatant 6. Fusion (formation of an oily phase) 7. Extractability.

The measurement values included in the examples are summarized in a table. The measurement results show that after a storage period of four weeks, when the temperature varied between -10 ° C and + 50 ° C during the 24 hours, the change at measuring points 1, 2, 3, 4 and 5 was not more than 10% in any of the given Example. No coalescence occurred, and any accompanying incompatible bottom precipitate could be completely re-emulsified.

Example 1

Solution I: 700 g of 2,4,5-T-ethylhexyl ester, technical (according to WHO specifications) 20 g of polyoxyethylene triglyceride and alkylarylsulphonate, biodegradable

Solution II: 22.7 g of phosphoted nonylphenyl polyethylene oxide (3-14 moles of ethylene oxide = EO), pH = 4.5-5.

100 g ethylene glycol 877.0 g distilled water 3.0 g ion-free silicone emulsion.

200 ml of solution II were first prepared and solution I was mixed with a Homorex mixer. After the addition, stirring was continued for a further 10 min. at maximum speed, then adjusted to pH 7.25 with semi-normal sodium hydroxide solution, made up to 1000 g with solution II and stirred once more for a while.

8 65010

Example 2

Solution I: 700 g of 2,4,5-T-ethylhexyl ester, technical (according to WHO specification) 20 g of polyoxyethylene triglyceride and alkyl aryl sulphonate, biodegradable

Solution II: 22.7 g of phosphated nonylphenyl polyethylene oxide (EO = 3-14 moles), pH = 6.5 100 g of ethylene glycol 877.0 g of distilled water 3.0 g of ion-free silicone emulsion.

The procedure is the same as in Example 1. The pH was adjusted to 7.4.

Example 3

Solution I: 600 g MCPA ethyl hexyl ester, technical 20 g fatty alcohol polyglycol ether

Solution II: 886.1 g of distilled water 98.5 g of ethylene glycol 15.4 g of phosphated alkylaryl polyethylene oxide.

The procedure is the same as in Example 1. The pH was adjusted to 7.15.

Example 4

Solution I: 636.4 g of 2,4,5-T-ethylhexyl ester, technical grade 18.2 g of fatty acid polyglycol ester

Solution II: 21.0 g of phosphated nonylphenyl polyethylene oxide (EO = 3-14 moles) pH = 6.5 91 g of ethylene glycol 800 g of distilled water 1.8 g of ion-free silicone emulsion.

9 65010

The procedure is the same as in Example 1. The pH was adjusted to 6.85.

Example 5

Solution I: 668.4 g of 2,4,5-T-ethylhexyl ester, technical mixture 19.0 g of a mixture of nonylphenyl polyethylene oxide, polyoxyethylene-polyoxypropylene segment polymer (molecular weight 1800-9000) and alkylarylsulfonate

Solution II: 22.0 g of phosphated nonylphenyl polyethylene oxide (EO = 3-14 moles), pH = 4.5-5 95.0 g of ethylene glycol 840 g of distilled water 3 g of ion-free silicone emulsion

The procedure is the same as in Example 1. The pH was adjusted to 6.90.

Example 6

The composition of the stock solution was the same as in Example 1. However, the sodium hydroxide required for neutralization was added to Solution II, pH = 7.60.

Example 7

Solution I: 667 g 2,4-DP-ethylhexyl ester, technical (according to WH0 specification) 19 g fatty acid polyglycol ester

Solution II: 383 g of distilled water 95 g of ethylene glycol 19.0 g of phosphated nonylphenyl polyethylene oxide (EO = 3 to 14 moles), pH = 4.5 to 5 3.0 g of ion-free silicone emulsion.

10 6501 0

First, 20 ml of solution II was prepared and 72 g of solution I was mixed with a high-speed mixer (Ultra Turrax). The mixture then warmed to about 60 ° C. After stirring for a further 5 minutes, the pH was adjusted to 7.50 g with semi-normal sodium hydroxide solution, made up to 100 g with solution II and stirred once more for a short time.

Example 8

Solution I: 667 g 2,4-DP-ethylhexyl ester, technical grade 19 g fatty acid polyglycol ester

Solution II: 383 g of distilled water 95 g of ethylene glycol 19.0 g of ethylene oxide condensate with a fatty amine (EO = 9-11 moles) 3.0 g of ion-free silicone emulsion.

The procedure is the same as in Example 7. The pH was adjusted to 7.55.

Example 9

Solution I: 655 g MCPA ethyl hexyl ester, technical grade 18.8 g fatty acid polyglycol ester

Solution II: 823 g of distilled water 94 g of ethylene glycol 20.0 g of phosphated nonylphenyl polyethylene oxide (EO = 3-14 moles), pH = 6.5 3.0 g of ion-free silicone emulsion.

In a mixer (Starmix), 200 ml of solution II was first prepared and solution I was slowly mixed so as to form a uniform emulsion. The mixture was heated to 70 ° C and homogenized with a circulating pump with a continuous flow of about 50 ml / min. It was then neutralized with semi-normal sodium hydroxide solution and filled with solution II to 1000 g. The pH of the emulsion 11,650,0 was 7.40.

Example 10

Solution I: 650.2 g CMPP-butyl glycol ester, purified 18.6 g fatty acid polyglycol ester

Solution II: 19 g of phosphated nonylphenyl polyethylene oxide (EO = 3-14 moles), pH = 4.5-5.93 g of ethylene glycol 817 g of distilled water 3 g of ion-free silicone emulsion.

The procedure is the same as in Example 7. The CMPP-butyl glycol ester was purified by mixing the ether solution of the ester with NaHCO 3 solution and then distilling. The pH of the emulsion was 6.85.

Example 11

Solution I: 650.2 g CMPP-butyl glycol ester, purified 18.6 g fatty acid polyglycol ester

Solution II: 19 g of ethylene oxide condensate with a fatty amine (EO = 9-11 moles) 93 g of ethylene glycol 817 g of distilled 3 g of ion-free silicone emulsion.

The procedure is the same as in Example 10. The pH was adjusted to 8.30.

Example 12

Solution I: 700 g of CMPP-ethylhexyl ester, purified as in Example 10 10 g of polyoxyethylene triglyceride and alkylarylsulfonate 12,650,10

Solution II: 881.7 g of distilled water 100 g of ethylene glycol 20 g of ethylene oxide condensate with a fatty amine (EO = 9-11 moles) 3.0 g of ion-free silicone emulsion.

The emulsion was prepared according to Example 10. The pH was adjusted to 9.50.

Example 13

Solution I: 250 g 2,4-D-i-propyl ester, technical 250 g MCPA-ethylhexyl ester, technical 20 g fatty acid polyglycol ester

Solution II: 20 g of phosphated nonylphenyl polyethylene oxide (EO = 3-14 moles), pH = 6.5 100 g of ethylene glycol 880 g of distilled water 3 g of ion-free silicone emulsion.

The procedure is the same as in Example 1. The pH was adjusted to 7.5.

Example 14

Solution I: 700 g of 2,4,5-T-ethylhexyl ester, technical grade 20 g of polyoxyethylene triglyceride and alkyl aryl sulphonate, biodegradable

Solution II: 22.7 g of phosphated nonylphenyl polyethylene oxide (EO = 3-14 moles), pH = 6.5 100 g of urea 877.0 g of distilled water 3.0 g of ion-free silicone emulsion.

The procedure is the same as in Example 1. The pH was adjusted to 7.15.

13 6501 0

Example 15

Solution I: 700 g of 2,4-DP-ethylhexyl ester, technical mixture of 20 g of nonylphenyl polyethylene oxide, polyoxyethylene-polyoxypropylene block polymer (molecular weight 1800-9000) and alkylphenyl sulfonate.

Solution II: 881.7 g of distilled water 100 g of glycerol 20.0 g of phosphated nonylphenyl polyethylene oxide (EO = 3-14 moles), pH = 2 3.0 g of ion-free silicone emulsion.

First, 200 ml of solution II was prepared and solution I was mixed with a Homorex mixer. After the addition, stirring was continued for 10 min. at a higher rate, after which the pH was adjusted to 7.50 with semi-normal sodium hydroxide solution, made up to 1000 g with solution II and stirred for a further time.

Example 16

Solution I: 700 g of 2,4-DP-ethylhexyl ester, technical mixture of 20 g of nonylphenyl polyethylene oxide, polyoxyethylene-polyoxypropylene segment polymer (molecular weight 1800-9000) and alkylphenyl sulfonate.

Solution II: 881.7 g of distilled water 100 g of glycerol 20 g of phosphated nonylphenyl polyethylene oxide (EO = 3-14 moles), pH = 2 3.0 g of ion-free silicone emulsion.

First, 200 ml of solution II was prepared, to which solution I was mixed using a Homorex mixer. After the addition, stirring was continued for 10 min. at a higher rate, filled with solution II to 1000 g and stirred for a further while. The pH was 4.45.

Example 17

Solution I: 500 g MCPA ethyl hexyl ester, technical 20 g fatty acid polyglycol ester.

Solution II: 889 g of distilled water 100 g of ethylene glycol.

25.0 g ethylene oxide condensate with fatty amine (EO = 9-11 moles) 3.0 g ion-free silicone emulsion.

Mixing and homogenization were performed as described in Example 1. The pH was adjusted to 8.05.

Example 18

Solution I: 400 g MCPA ethylene hexyl ester, technical 20 g fatty acid polyglycol ester

Solution II: 889 g of distilled water 100 g of ethylene glycol 25.0 g of ethylene oxide condensate with a fatty amine (EO = 9-11 moles) 3.0 g of ion-free silicone emulsion.

Stirring and homogenization were performed as in Example 1. The pH was adjusted to 8.1.

Example 19

Solution I: 500 g MCPA ethyl hexyl ester, technical 20 g fatty acid polyglycol ester.

Solution II: 880 g of distilled water 100 g of ethylene glycol is 6501 0 10 g of ethylene oxide condensate with a fatty amine (EO = 9-11 moles) 1.5 g of ion-free silicone emulsion 80.0 g of a 2% solution of xanthan gum.

First, 400 ml of solution IX was prepared, to which solution I was mixed as in Example 1, the pH was adjusted to 7.80 with semi-normal sodium hydroxide and filled with water: ethylene glycol 9: 1.

Example 20

Solution I: 400 g MCPA ethyl hexyl ester, technical 20 g fatty acid polyglycol ester

Solution II: 880 g of distilled water 100 g of ethylene glycol 10 g of ethylene oxide condensate with fatty amine (EO = 9-11 moles) 1.5 g of ion-free silicone emulsion 130 g of a 2% solution of xanthan gum.

The procedure is the same as in Example 18. The pH was adjusted to 7.9. Example 21

Solution I: 600 g MCPA-ethyl hexyl ether, technical 20 g alkylaryl polyglycol ether

Solution II: 886 g of distilled water 98.4 g of ethylene glycol 15.5 g of phosphated alkylaryl polyethylene oxide.

The procedure is the same as in Example 1. The pH was adjusted to 7.45.

ie 6501 0

Example 22

Solution I: 650 g 2,4, D-butyl ester 20 g fatty acid polyglycol ester

Solution II: 897.7 g of distilled water 99.7 g of ethylene glycol 13.9 g of phosphated alkylaryl polyethylene oxide.

The procedure is the same as in Example 1. The pH was adjusted to 7.13.

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Claims (11)

1. Of one or more herbicidally active phenoxyalkanecarboxylic acid esters consisting of water-based, stock stable, concentrated emulsion, in which is used an oil-soluble emulsifier and a water-soluble dispersant, characterized in that it contains one or more clay in esters soluble emulsifying agent. , 01 - 11.1 parts by weight of 100 parts of ester, the HLB value of the emulsifier being 9-16 and selected from a group consisting of fatty acid polyethylene glycol ester, polyethylene glycol ether of fatty alcohols, glycerides or alkylphenols, polyoxyethylene and polyoxypropylene segment polymers, mixtures of this polyethylene glycol ester, polyethylene glycol ether or polyethylene glycol polypropylene glycol segment polymer together with alkylaryl sulfonates, and one or more ionic or nonionic, water-soluble dispersing agents from a group consisting of phosphated alkylene oxide and ethylene oxide ethylene oxide conventional cold preservatives, the effective emulsion content of the concentrated emulsion being 30-75% by weight, viscosity 50-3000 mPa, droplet size 1-5 pm and pH 4-10. 2. Stable, concentrated emulsion according to claim 1, characterized in that as ester-soluble emulsifiers, fatty acid polyethylene glycol esters and water-soluble dispersants are phosphated alkylaryl polyethylene oxides. 3. Stock stable, concentrated emulsion according to claim 1, characterized in that as ester-soluble emulsifiers, polyethylene glycol polypropylene glycol segment polymers are used together with alkylarylsulfonates and as water-soluble dispersants, phosphated alkylaryl polyethylene oxides are used. 4. A stable, concentrated emulsion according to any one of claims 1-3, characterized in that octyl ester of enoxyalkanecarboxylic acid is used as a herbicidally active phenoxyalkanecarboxylic acid ester. 5. A stable, concentrated emulsion according to any of claims 1-4, characterized in that it contains 0.5-5% by weight of emulsifier. 6. Stable, concentrated emulsion according to claim 5, characterized in that it contains 1-2% by weight of emulsifier. 7. Stable, concentrated emulsion according to any of the patent claims.