SK39197A3 - Stable mixture of water and methazachlorine - Google Patents

Abstract

A liquid mixture contains: 2-chloro-(2',6'-dimethyl-N- pyrazol-1-yl-methyl)-acetanilide, that may be substituted up to 40 % of its weight by one or several other plant protecting agents; a copolymer obtained by copolymerising (b1) one or several C2-C20-mono-olefins; (b2) one or several mono-olefinically unsaturated C4-C8-anhydrides; and (b3) if required other mono-olefinically unsaturated compounds copolymerisable with comonomers (b1 and b2), and whose anhydride and possibly other hydrolysable groups and/or free carboxyl groups may be at least partially converted into salts; water; and usual auxiliary agents of compositions. Also disclosed is a process for preparing this mixture and its use for controlling undesirable plant growth.

Description

Field of the invention

The present invention relates to a stable composition comprising water and metazachlor, its preparation and use for the destruction of unwanted plants.

BACKGROUND OF THE INVENTION

It is generally known that plant protection agents prepared in the form of concentrated suspensions often tend to sediment the active ingredients. In many cases, crystallization of the active substance is considered to be the cause of sedimentation.

For aqueous spraying of two fungicidal compounds of the triazole type which are prepared by diluting the emulsion concentrates with water, DE-A 39 10 921 proposes Nalkyllactam and DE-A 39 10 922 distyrylphenyltriglycol ether as crystallization inhibitors.

WO 93/1560 discloses that as crystallization inhibitors in liquid pesticide mixtures, especially emulsion concentrates, aliphatic C 1 -C ₈ -carbonic acids having 1 to 3 carboxyl groups and, if possible, hydroxyl groups in the molecule can also be used.

EP-A 17 879 discloses the stabilization of aqueous suspension concentrates of linuron against the crystallization of the active ingredient by the action of liposoluble disazo-dyes.

It has previously been found that 2-chloro- (2 ', 6'-dimethyl-N-pyrazoir-1-ylmethyl) acetanilide, commonly known as metazachlor, may form various crystal modifications, with monoclinic metazachlor suspension concentrates having smaller sediment formation tendency as triclinic metazachlor suspension concentrates (EP-A 411 408).

metazachlor

Especially at elevated ambient temperature, it is possible that the stability of aqueous suspension concentrates of metazachlor, even of monoclinic modification, may not be satisfactory. Their usability in a warm climate is thus considerably limited.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome this drawback.

Accordingly, a liquid composition has been discovered which contains:

(A) 2-chloro- (2 ', 6'-dimethyl-N-pyrazol-1-ylmethyl) -acetanilide, up to 40% by weight of which can be replaced by one or more other plant protection products,

B) a copolymer which is prepared by copolymerization of b1) one or more Ca-C 10 monoelefins, b2) one or more monoolefinic unsaturated C ₄ -C ₈ anhydrides, b3) optionally other monoolefinic unsaturated compounds that are copolymerizable with comonomer (b1); (b2), wherein the anhydride and optionally other hydrolyzable groups and / or free carboxyl groups may be at least partially converted into salt forms.

(C) water; and

D) conventional formulation aids.

Further, a process has been found to form this mixture and to use it to eliminate unwanted plant growth.

The most important cause of sedimentation of metazachlor in suspension concentrates at elevated temperatures is probably that the substance forms crystals that are larger than the original particles of the substance (which were still irregularly shaped), and these then settle to a greater extent at the bottom of the container.

Those skilled in the art are already aware of the use of salts of copolymers of maleic anhydride and diisobutylene as a stabilizer of granules of plant protection agents and

-3improvement of their solubility in water (see FR-A 2 545 325). When metazachlor is the only plant protection agent in the mixture, its proportion is usually 20 to 60, or more preferably 40 to 60% by weight.

The production of metazachlor is generally known (see DE-A 26 48 008, DE-A 28 30 764, EP-A12 216).

The copolymer salt (B), which is added to the mixture to prevent sedimentation of metazachlor, comprises an essential comonomer (b1), one or more C ₂ -C ₂₀ -monoolefins, preferably C ₄ -C ₁₂ -monoolefins, and especially 1-olefins of this of the type and in particular trimethylpentene 2,4,4'-trimethylpentene-2 and / or 2,4,4'trimethylpentene-1 in the ratio of 0.6: 1 to 6: 1 or the diisobutylene sold.

In addition, isobutene, ethylene, propylene, butene-1, styrene and α-methylstyrol are suitable as comonomers (b1).

The proportion of comonomers (b1) in the copolymer is preferably 30-50, more preferably 4050 mol. %.

The second essential comonomer (b2) of the copolymer is one or more unsaturated C ₄ -C ₈ -anhydrides or similar C ₄ -C ₆ -anhydrides, in particular maleic anhydride and in addition icatonic anhydride, citraconic anhydride and methylenemalonic anhydride.

The proportion of comonomers (b2) in the copolymer is preferably 50-70, more preferably 5060 mol%.

The molar ratio of components (b2) and (b1) of the copolymer is usually 1: 1 to 20: 1, more preferably 1: 1.

If desired, the copolymerization of components (b1) and (b2) may be carried out in the presence of other copolymerizable monoolefinic unsaturated compounds which, in particular in the presence of comonomers (b1) and (b2), have sufficient solubility in the reaction medium under copolymerization conditions.

As the comonomer (b3), suitable are acrylic and methacrylic acid having free carboxyl groups, acrylamide, acrylonitrile, methacrylonitrile, C 1 -C ₈ alkyl acrylates, C 1 -C ₆ alkyl methacrylates, C 1 -C ₆ -carboxylic acid vinyl ester with C , -C ₈ alkyl or C ₆ -C ₂₀ -aryl groups, N-substituted maleic imides or comonomer mixtures (b3).

The content of component (b3) is usually between 0 and 20 mol%. More preferably, the content is 0 to 10, and most preferably 0 to 5 mol%.

Preferably, salts of such a copolymer which consist only of components (b1) and (b2) in a molar ratio of 1: 1 and in particular of the alternating copolymer are used to prepare the compositions of the invention.

Particularly preferred is a copolymer salt of composition and structure as obtained by the copolymerization of maleic anhydride and diisobutylene.

The copolymerization of the comonomers (b1), (b2) and optionally (b3) can be carried out by known methods or analogous methods (see e.g. EP-A 9 169, EP-A 9 170, EP-A 276 464).

The copolymers preferably have a molar mass of 1,000 to 100,000, more preferably 2,000 to 50,000, most preferably 10,000 to 20,000 (mean weight measured by light scattering).

For the preparation of the mixture according to the invention, a copolymer of the type described above is used whose anhydride groups and optionally other hydrolyzable groups, e.g. nitrile or ester groups, and / or free carboxyl groups are at least partially converted into salt forms.

Preferably, these groups are converted to salt form (neutralized) to 50 to 90% (degree of neutralization), more preferably to 60 to 80%.

In the case of these salts, the comonomer copolymerization product (b1), (b2) and optionally (b3) are usually suspended first in water and preferably hydrolyzed with water vapor. By adding a suitable amount of a base, the carboxyl groups are converted to the salt form. By using different bases, a mixture of salts can also be obtained.

Preferably, alkali metal salts, in particular sodium or potassium salts, and in addition alkaline earth metal salts, ammonium salts or mixed salts of copolymers are prepared, among which ammonium salts are preferred which contain the following cations: ammonium (NH ₄ ), ethanolammonium [ (H ₃ NOCH ₂ CH ₃ ⁺ )] and cations of the NR ₃ H ^{+ type} , in which the R radical may be any of the following:

-C 1 -C 4 -alkyl groups, C 1 -C ₄ -alkyl groups such as methyl, ethyl, isopropyl and n-butyl groups,

- C ₁ -C ₄ -alkanolamine groups, in particular methanolamine and ethanolamine groups,

C ₆ -C ₁₀ -aryl groups, especially phenyl and / or

- aryl (C ^ CJ-alkyl, in particular aryl (C ₁ -C ₂₎ alkyl groups such as phenethyl and benzyl, or wherein the two radicals R together with the nitrogen atom carrying them, form a morpholine or piperidine circle.

The preferred ammonium salts are in particular ammonium (NH ₄ ^+), trimethylammonium, triethylammonium, ethanolammonium, diethyl-, triethanolammonium salt, and morpholine.

Most preferred are sodium salts and also potassium, calcium and ammonium _(NH4 +) salts of the copolymer.

Copolymers, especially alternating ones, of diisobutylene and maleic anhydride, whose anhydride groups are hydrolyzed to 50 to 90%, more preferably to 60 to 80%, to sodium carboxylate groups have proved to be very suitable for stabilizing aqueous suspensions of metazachlor.

It is preferred to add the copolymer salt (B) to the mixture in the form of particles up to 100, more preferably up to 50 mm.

The proportion of copolymer salt in the mixture is usually 0.02 to 10, preferably 0.5 to 4% by weight. based on the weight of metazachlor.

In addition to metazachlor, copolymer salt and water, the composition of the invention also contains other conventional molding agents such as dispersants, crosslinkers,

-6 thickeners and antifoams, bacteriocidal and antifreeze agents.

The proportion of these molding agents is in total from 2 to 15, preferably from 8 to 13% by weight, based on the weight of the finished mixture.

As dispersants, commercially available water-soluble anionic and non-ionic compositions can be used, with the following structures:

R'-SOA salt, -SO4-R ² salt, ³ R - (EO) n H, R ³ - (PO) n H, R ³ - (EO) n (PO) _m -H.

The substituents used in the above formulas have the following meanings:

R ^{@ 1 is a} linear or branched alkyl group having 1 to 20 carbon atoms, preferably 8 to 18 carbon atoms, e.g. dodecyl

aryl, e.g. phenyl or naphthyl

aryl, especially phenyl, with a linear or branched alkyl group as mentioned, e.g. dodecylphenyl

- some condensation product of phenol with urea and formaldehyde

R ² - straight or branched alkyl of 1 to 20 carbon atoms, preferably 8 to 18 carbon atoms, e.g. dodecyl

- 2 to 5 ethoxy units of polyethoxy with a linear or branched alkyl group attached thereto

polyethoxy of 2 to 25 ethoxy units with a substituted aryl radical attached via a linear or branched alkyl group, e.g. nonylphenyl polyethoxy with 20 ethoxy units.

R ^{3 is} linear or branched alkyl having 1 to 20 carbon atoms, preferably 8 to 18 carbon atoms, e.g. dodecyl

aryl, especially phenyl, with a linear or branched alkyl group as mentioned, e.g. dodecylphenyl

EO = ethyleneoxy, PO = propyleneoxy n and m are independent integers from 4 to 12

Further suitable nonionic dispersants are block polymers of propylene oxide and ethylene oxide of the formula:

. HO (CH ₂ CH ₂ O) _x - (CHCH ₂ O) _y - (CH ₂ CH ₂ O) _z H ch ₃ where x, y and z are numbers chosen such that the total molecular weight is greater than 1000. of this type are generally mixtures of several compounds of this formula that vary in size x, y and y are usually prepared by the addition of ethylene oxide to polypropylene glycol. Examples are Pluronic PE 6200 and Pluronic PE 10500.

All conventional surfactants which are used as auxiliaries for the formulation of plant protection products can be used as dispersants. The sodium salt of the condensation product of phenolsulfonic acid, urea and formaldehyde is preferred. Such condensation products are described e.g. DE-A 11 13 457 and DE-A 11 78 081. An example of this class of compounds is Wettol D1 (BASF).

When using block polymers as dispersants, a product comprising a polyoxipropylene oxide core having a molecular weight of 3,000 to 3,500 and an ethylene oxide content of 50% i.e. having a total molecular weight of about 6,000 to 7,000. Examples of such dispersants are Pluronic products of BASFWyandotte Corporation.

The following products are suitable as crosslinkers in the compositions according to the invention:

- polyoxyethylene / polyoxypropylene fatty alcohols such as WETTOL LF (BASF)

- polyoxyethylene / polyoxypropylene fatty amides such as ATPLUS (Atlas) and Ethomeen (Akzo)

- fatty acid esters, resp. fatty acid ester ethoxylates such as ARLACEL, ATMER, ATMOS and ATPET (fa Atlas)

- polyoxyethylene or polyoxyethylene / polyoxypropylene oxalic alcohols such as LUTENSOL AO, LUTENSOL TO (fa BASF)

-8- polyoxyethylene or polyoxyethylene / polyoxypropylene alkylphenols such as e.g. LUTENSOL AT (by BASF)

Crosslinkers serve to enhance the biological effect of the composition by promoting cross-linking and / or transport of the active ingredient to the surface and inside the plant.

Thickeners used are polysaccharides known from the literature, in particular based on xanthan rubber, such as e.g. Kelzan (Kelco, USA) or Rhodopol (Rhone-Poulenc).

Further, antifreeze agents such as 1,2-propylene glycol, bacteriocidal and antifoam agents are generally added to the composition of the invention.

Further, the composition may contain other plant protection agents. These contain up to 40, preferably 30% by weight. metazachlor.

Suitable further plant protection agents are, in particular, herbicides, e.g. 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (Atrazine) or 4-tertiary butylamino-2-chloro-6-ethylamino-s-triazine (Terbutylazine) and further securing agents (safeners) such as e.g. . 1- (dichloroacetyl) -hexahydro-3,3,8a-trimethylpyrrolo- (1,2-a) pyrimidin-6 (2H) -one (Dicyclonon) and further fungicides or growth regulators.

Preferably, so much water is used to prepare the composition that its proportion in the composition (based on its weight) is between 30 and 70%, more preferably between 40 and 60%.

The mixture is generally prepared by mixing the ingredients. In order to achieve the desired particle size of the mixture, it is necessary to grind the solid components of the mixture before mixing and / or the resulting mixture. Preferably, the milling takes place in a ball mill, especially with a cooled surface. The operating temperature is usually between 4 and 40 ° C, more preferably between 20 and 35 ° C.

In the mixture thus obtained, as a rule 20 to 90%, more preferably 40 to 70% of the solid particles have a particle size of less than 2 mm (measured by a Cilas 715 granulometer from Cilas, Marcoussis, France).

It is preferred that the solids content of the suspension concentrate be 25 to 60% by weight, more preferably 40 to 60%.

The mixture thus obtained exhibits better storage stability than aqueous metazachlor solutions to which the copolymer salt described above has not been added during manufacture.

For quantitative assessment of storage stability, it is appropriate to measure the particle size increase of the solids over time. the measurement may be carried out in a known manner, e.g. by means of an apparatus using laser beams to measure the particle size in the diluted solution, e.g. with a Cilas 715 granulometer (see above).

In the application according to the invention, it is usually carried out by first mixing the mixture with 25 to 100 parts, preferably 50 to 200 parts, of water. For spraying, a mixture with a solids content of from 0.1 to 4, preferably from 0.5 to 2% by weight, is prepared by dilution with water. The spray is then applied to the target plants or their surroundings. In addition, it is possible to adequately treat the seeds of the target plants before sowing, or to treat both seeds and plants.

Where aqueous solutions of the active substances are poorly tolerated by certain cultures, application techniques may be used in which the spraying is preferably not applied to the foliage of the crop plants but applied to the weeds growing under them or to the open soil (post-directed or lay-by).

Depending on the purpose of use, the season, the target plant and its developmental stage, the required amount of metazachlor active ingredient in the form of the mixture according to the invention is 0.5 to 7, more preferably 0.5 to 5, even more preferably 2 to 3 kg / ha.

The use of suspension concentrates of active substances for plant protection is otherwise generally known and therefore does not require any further explanation.

DETAILED DESCRIPTION OF THE INVENTION

-10Example 1

Mixture consisting of:

50% by weight. 2-Chloro- (2,6-dimethyl-N-pyrazol-1-ylmethyl) -acetanilide (Metazachlor) 7% by weight. 1,2-propylene glycol as an antifreeze agent 2% by weight. Wettol D1 (sodium salt of acid condensation product) 0.3% by weight. phenolsulfonic, urea and formaldehyde, BASF, Germany) as dispersants Kelzan (xanthan rubber polysaccharide, Kelco, USA) as thickeners 3% by weight. Pluronic PE 10500 (block polymer with polypropylene oxide) cores having a molar mass of about 3250 on which it is 37.7% by weight. bonded ethylene oxide up to a molecular weight of about 6500) dispersants and waters

was milled for 0.25 hours. in a discontinuously operating pearl mill (Dyno KDL type, Bachofen). Its particle size was then determined using a laser meter (Cilas 715 type, Cilas, Marcoussis, France).

Before the second grinding, 10 wt. parts of a commercially available sodium salt of an alternating diisobutylene maleate anhydride copolymer (mean molecular weight 12,000 measured by light scattering, degree of neutralization 75%).

After six months of storage at different temperatures, the percentage of particles whose maximum diameter was less than or equal to TG was determined and listed in the following table.

Particle size distribution of aqueous metazachlor suspension with and without addition of copolymer

about H ABOUT about C CM r ~ σι r * M · 0 VO rd rd WHAT * r r4 σι CM WHAT w cn m · σι ». about r * rd VO WHAT M * The σι σι tO * σι σι m · » σι σι r- The σι σι ABOUT ABOUT fd about 3 m at • 0 C * 3 * r- m 0 «3 * r-i 0 they * > CM CM r- H σι m WHAT about 0 CM what d) WHAT WHAT Cl 01 about M i-4 0 A (U Q) IN σι CM r · σι σι 0 i-4 fd • H they σι within and » H CM r * P> about CM M ¹ WHAT r WHAT Cl about ABOUT i-4 2 0 you about > tn H ABOUT C  C "C3 CM VO 0 WHAT ΙΩ CM (U you • it · » e !> ABOUT CM c- about m 0 about 0 m m ¹ within σι σι cn about 3 Ό fd about you in RD w 0 Λ n Φ within ιΛ * r * H H about M • d r * about The 0 Cl about rd h 3 what 'And * r- cn σι σι fd (U • 0 about > (0 0 , u you about about n ABOUT C • H 'es r * t 0 C r * 44 W w • it The * <D • rl > U  1 '1 S3 * WHAT M * r- σι σι ABOUT n • 3 * r- σι σι σι ABOUT id 0 x: P about (0 • H "3 * ABOUT σι you P 0) • H P • H σι * 3 · WHAT 0 about > u <D ABOUT about C m m r- σι about -H H > 10 about cP CM about 0 * « cn r * about The cn The σι The σι The rd r * r4 r- WHAT σι σι about about WHAT m r- σι σι σι about • H Ό 0 rd A •about CM CM ABOUT 'T' WHAT rj m within CM σι about • rM n M * r- σι about H 3 "U. about CJ r * about with >> ABOUT, about ABOUT about. <d about • rl you C • rl rd about JP P you > rt fl) > -about g 0 Ό about. you you Λ rd about x ABOUT w m M 3 CM WHAT 0 WHAT CM within CM WHAT M ¹ VO M - J id R-T CM cn M * within σι

Claims (8)

A liquid composition comprising (A) 2-chloro- (2 ', 6'-dimethyl-N-pyrazol-1-ylmethyl) -acetanilide, which may be replaced by up to 40% of its own weight by one or more plant protection products, B) a copolymer which is prepared by copolymerization of b1) one or more C ₂ -C ₂₀ monoolefins, b2) one or more monoolefinic unsaturated C ₄ -C ₈ anhydrides, and b3) optionally other monoolefinic unsaturated compounds which are copolymerizable with a comonomer ( b1) and (b2), whose anhydride and optionally other hydrolyzable groups and / or free carboxyl groups can be at least partially converted into salts. (C) water; and (D) the usual formulation aids A composition according to claim 1, characterized in that it consists of (a) 20 to 60% by weight. component A b) 0.02 to 10% by weight. component B, c) 30 to 70% by weight. component C, and d) 2 to 15% by weight. component D. Mixture according to claim 1 or 2, characterized in that components (b1) and (b2) are contained equimolarly in the copolymer. Composition according to claims 1 to 3, characterized in that diisobutylene is used as component (b1) for the production of the copolymer. Mixture according to one of Claims 1 to 4, characterized in that maleic anhydride is used as component (b2) for the production of the copolymer. -136. The composition according to claims 1 to 5, characterized in that the copolymer salt used is the sodium salt of the copolymer diisobutylene maleate anhydride. A process for the preparation of a composition according to claims 1 to 6, characterized in that components A to D are mixed with one another and the solids or the finished mixture are ground before mixing. A method for preventing undesired plant growth, characterized in that the seeds, plants and / or their surroundings are treated with a herbicidally effective amount of the composition according to claim 1. Use of the composition according to claim 1 for preventing undesirable plant growth.