DD202232A5 - WAESSED CONCENTRATED SUSPENSIONS BASED ON NEBURON AND THEIR MANUFACTURE - Google Patents

Abstract

The invention relates to herbicidal compositions based on neburon and their preparation. They are concentrated aqueous suspensions which, in addition to neburon and conventional wetting agents, dispersants and thickeners, contain a stabilizing agent of the formula 1 in which X, Y and Z are either or independently H, halogen or C 1 to C deep 4-alkyl which is optionally halogenated, and RC 1 to C deep 3-alkyl. The compositions are suitable for selective weed killing in crops.

Description

The invention relates to novel herbicidal compositions based on Neburon, which are concentrated aqueous solutions, as well as their preparation and use.

Characteristic of the known technical solutions Neburon with the chemical nomenclature designation

1- (3,4-dichlorophenyl) -3-methyl-3-n-butylurea is a known herbicide which is used in particular for selective weed killing in crops, and especially in cereals, and especially before emergence.

Commercially available herbicidal compositions based on neburon have long been available in the form of wettable powders. For some years, however, attempts have been made to prepare liquid compositions based on this active ingredient, in particular concentrated aqueous suspensions which offer considerable advantages in terms of easier storage (reduced volume), handling (no dust formation) and use (easier dosage).

570-PH1981 DDR SF-8k

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Several compositions of this type have already been disclosed, which in addition to neburon, alone or in admixture with generally at least one other herbicide, contain a thickening agent and at least one surfactant as wetting agents and / or dispersing agents.

However, these compositions are not physically stable, since after only a few months of storage, thickening of the compositions leads to sedimentation and irreversible formation of a paste-like pulp, which can occur at elevated storage temperature until complete precipitation.

When dispersed in water, therefore, the composition

again

not or only very difficult / resuspended; in the worst case, the solid particles of the dispersion may have a diameter sufficient to clog the atomizing nozzles.

Explanation of the essence of the invention

The invention is based on the surprising finding

from that can be formulated by using certain stabilizers liquid herbicidal compositions based on Neburon, which have high storage stability and can be stored for long periods.

The invention relates to novel concentrated aqueous suspensions based on Neburon, which contain a thickening agent, at least one wetting agent and / or at least one dispersant in the usual way as auxiliaries; the suspensions according to the invention are characterized in that they furthermore contain 1-10% by weight and preferably 2-6% by weight,

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based on the weight of the neburon, a stabilizing agent of formula I.

υ ζ

in which mean

X, Y and Z are each, independently of one another, hydrogen, halogen or C 1 - to C 1 -alkyl which is optionally halogenated, and

RC ₁ - to CyAlkyl.

Preferred compositions according to the invention contain as special stabilizer a compound of formula II

CH ₃ X ¹ - (Tj) -. NH-CN (II),

0 ^R '

in which mean

X ^{1 is} hydrogen, halogen, preferably chlorine or bromine,

or C, - to

Y ^{1 is} hydrogen, halogen, preferably chlorine or sulfur, or trifluoromethyl

and R ^{1 is} methyl or ethyl,

- I-

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wherein at least one of the substituents X 'and Y' is preferably a halogen atom.

Good results have been obtained with stabilizers of general formula II in which X 'is chlorine or bromine or methyl and Y' is either hydrogen when x ^{1 is} chlorine or bromine, or chlorine or bromine.

The content of stabilizing agent according to the invention is generally between 1 and 5% by weight, based on the weight of the nebron. Levels below 1% by weight generally do not result in sufficient stabilization of concentrated aqueous suspensions. On the other hand, amounts above 10% by weight no longer improve the stabilizing effect and, at the same time, are disadvantageous from an economic point of view. You may also bring the disadvantage that doses are achieved in which harmful herbicidal side effects are achieved.

The compositions according to the invention are further characterized in that at least 95% by weight of the solid particles in suspension have a diameter of less than 20 μm and at least 50% by weight have a diameter of less than 7 μm and preferably not more than 5 μm.

The herbicidal compositions according to the invention contain as active ingredient neburon, which may be present alone or in admixture with other additional herbicides, for example Diphenyietherderivaten such as nitrofen and Bifenox, urea derivatives such as isoproturon, triazine derivatives such as terbutryn or atrazine or dinitroamines such as pendimethalin and any other herbicides containing the Stability of the neburone in the compositions according to the invention does not appreciably affect.

- 1 -

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The concentrations of the formulations of the invention on Neburon vary in the generally used range of 100 to 6GO g / L and preferably 200 to 500 g / L. Accordingly, according to the proportions indicated above, the suspensions contain from 0.2 to 3.6 parts by weight, and preferably from 0.25 to 3 parts by weight, of stabilizing agent.

The thickening agents used in the compositions according to the invention are products which, when added to water or aqueous solutions or suspensions of pesticides, impart pseudoplastic properties to them.

Thickeners which can be used according to the invention can be of inorganic or mineral and organic origin.

Inorganic or mineral thickeners are for example Attapuigite, Bentonite, Laponite and colloidal silicic acids.

Organic thickeners are, for example, alginates and in particular hydrophilic biopolymers of the heteropolysaccharide type, these biopolymers being preferred thickeners according to the invention.

The amount of thickener in the compositions according to the invention is generally between 0.01 and 15% by weight and advantageously between 0.05 and 10% by weight. When the thickener is a hydrophilic, heteropolysaccharide biopolymer, the amount of thickener is generally between 0.01 and 2% by weight and preferably between 0.05 and 0.5% by weight.

The heteropolysaccharide hydrophilic biopolymers which can be used according to the invention are in themselves

- «- 242354 δ

knew products. They have a molecular weight over 200,000 and preferably over 1,000,000, have pseudoplastic properties and are generally obtained by fermentative action of bacteria of the species Xanthomonas on carbohydrates. For these biopolymers, there are sometimes other, quite different names such as hydrophilic Xanthomonas colloids, heteropoiysaccharidic gums, xanthan gum and extracellular heteropoclysaccharides of Xanthomonas or bacteria of the family Pseudomonaceae. The term biopolymer is further understood in the sense that these are polymers derived from a biological process, in the present case from a bacterial fermentation.

The bacteria used to make these biopolymers are in most cases strains of Xanthomonas campestris, but other Xanthomonas species such as Xanthomonas carotae, Xanthomonas incanae, Xanthomonas begoniae, Xanthomonas malvacearum, Xanthomonas vesicatoria, Xanthomonas translucens, Xanthomonas vasculorum and others may also be used. Carbohydrates suitable for the fermentation of carbohydrates with Xanthomonas bacteria are glucose, cane sugar, fructose, maltose, lactose, galactose, starch, potato starch and the like.

In addition to the thickening agent of the above type, the compositions according to the invention in the preparation of aqueous concentrated suspensions contain conventional surface-active agents, ie at least one wetting agent and at least one dispersing agent. These two properties can also be present with the same product; in this case, for simplicity, a single, double-acting agent can be used.

Cheap wetting agents are preferably nonionic agents such as ethoxylated alkyl and polyalkylphenols, ethoxylated aryl and poly

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arylphenols. ethoxylated alcohols and ethoxylated fatty amines. The compounds are generally present in the concentrated aqueous suspensions in an amount of 0.5-5% by weight and preferably 1-3% by weight.

Surfactants suitable as dispersants are generally anionic linkages such as, for example, salts of strong acids such as phosphates and sulfonates, condensation products of ethylene oxide with alkyl or polyalkylphenols or aryl or polyacrylphenols which generally contain from 8 to 20 moles of ethylene oxide per molecule.

The dispersant is generally present in the concentrated aqueous suspensions of the invention in an amount of 0.5-5% by weight and preferably 1-3% by weight SS.

The concentrated aqueous suspensions of the present invention may further advantageously contain other conventional adjuvants such as antifreeze agents (5-10% by weight), antifoam agents such as silicone oil emulsions or fatty alcohols (0.2-1 wt% 3S), and further, if the thickener is a biopolymer. a preservative (0.1-0.5 wt.%), for example, a formaldehyde-based composition.

The compositions according to the invention can be prepared, for example, in two stages.

In the first step, the wetting agent, the dispersant and optionally an antifreeze are introduced into water.

In the second stage Meburon and optionally the additional herbicides or herbicides and the stabilizing agent under

- · * 24 2 3 5 Λ

Stirring in the resulting aqueous composition dispersed. The suspension obtained is then comminuted in a comminution device, for example a ball mill (eg in a Dynomill bead mill). If a mineral thickener is used, it is added in the second _Sty_te_-a-ls-such.

On the other hand, when the thickener is a copolymer, it is added in the form of a predispersion in a small amount of water containing the preservative (for example, aqueous 40% formalin solution). AusführungsOeia ^ igIe

The following examples illustrate the preparation and compositions of the concentrated aqueous suspensions according to the invention and their improved storage stability compared to conventional formulations.

Example 1

First, an alkylphenol ether with 13 moles of ethylene oxide as wetting agent, one with an alkylphenol ether with 9 moles of ethylene oxide in the form of the phosphate as dispersant and glycol as antifreeze in water are introduced as dispersants. Then neburon and 3- (3,4-dichlorophenyl) -l.ldimethylurea are added to the resulting composition with stirring. The suspension obtained is comminuted in a ball mill (Dynomill).

Subsequently, a predispersion of a heteropolysaccharide hydrophilic biopolymer in an aqueous solution containing formaldehyde as a preservative and a silicone oil as an antifoaming agent are added with stirring.

- T5 - -

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The amounts of the individual components were calculated to correspond to the following composition:

Neburon 36.4 glycol (antifreeze) 5

Wetting agent 2.5

Dispersant 2.5

Antifoam o, 4

Preservative ο, 3

Thickener 0.2

Stabilizing agent ι

Water at 100.

In this formulation, the stabilizer used was 3- (3,4-dichlorophenyl) -l.l-dimethylurea; the amount was 2.75% by weight based on the amount of neburon.

In the same way, an analogous composition was further prepared with the difference that it did not contain a stabilizer according to the invention.

The two compositions were at the beginning of t, after 1 month at 50 ⁰ C in a drying oven and after 5 weeks left in a drying oven at various temperatures with a weekly cycle of 4 days at + 35 ⁰ C and then 3 days at - 10 ⁰ C (G / D test, freeze / Wiederauf tau test) subjected. The three tests used were:

1) Self-disperse :

5 g of the suspension were placed in a test tube filled with 250 ml of water. The appearance of the dispersion was then evaluated according to the following ratings:

- ** - 2 ^ 23 5 A 6

- Dispersion at the first drop: very good (s.g.)

- The product falls into dispersed

Flakes off: moderate (m)

- the product falls in compact

Block out: bad (0).

2) Dynamic viscosity:

In the measurements, a rotational viscometer (Rheomat 30, Fa. Contraves) was used.

3) Mean particle diameter:

The mean particle diameter was determined by a counter (Coulter counter) (total weight%).

The results obtained for each suspension tested are summarized in Table 1; each test was performed at the indicated three times.

From the results obtained, the following is clear:

1. At time t, the two suspensions had the same properties;

2. after 30 days at 50 ^° C., the known suspension was no longer self-dispersible or pourable, which corresponds to a very considerable enlargement of the particle diameter, while the suspension according to the invention with the special stabilizing agent retained the excellent initial properties;

3. the known suspension exhibited poor behavior in the freeze / thaw test, while the suspension stabilized according to the invention retained its initially excellent properties.

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Example 2

Analogous results were obtained, wherein as stabilizing agent in the inventive composition of Example 1 instead of 3- (3.4-dichlorophenyl) -II-dimethylurea an equal amount of 3- (4-chlorophenyl) -II-dimethylurea, 3- (3-chloro 4-iTiethylphenyl) -II-dimethyl, urea, 3- (3-bromophenyl) -II-dimethylurea, 3- (4-bromophenyl) -li-d-triethyl} "urea, 3- (4-methylphenyl) -II- dimethylurea or 3- (3-chloro-4-methylphenyl) -l-methyl-l-ethylurea in the same amount were used.

Example 3

The procedure was as in Example 1 with the difference that the following compositions were prepared:

Composition 3A% by weight on 100 Composition 3B% by weight neburon 25 45 Antifreeze 5 β wetting agent 2 3 dispersants 1.5 2.5 Anti-foaming agents 0.3 0.5 preservative 0.3 0.3 thickener 0.2 0.2 Stabilizer 0.5 (corresponding to 3.3% by weight, based on neburon) 1.5 water on 100.

In these formulations, as stabilizer, 3- (3,4-dichlorophenyl) -1, 1-dimethy1-

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urea, 3- (4-chlorophenyl) -i.i-dimethylurea and 3- (3-chloro-4-methylphenyl) -l-1-dimethylurea; the proportion by weight of 0.5% by weight, based on the formulation, corresponds to a content of 2% by weight, based on neburon; the proportion by weight of 1.5% by weight, based on the formulation, corresponds to a proportion of 3.3% by weight, based on neburon.

Example 4

The procedure was as in Example 1, wherein the following composition was prepared:

Wt .-%

Neburon 23

Isoproturon 23

Antifreeze 5

Wetting agent 2.5

Dispersant 1.5

Antifoam 0.5

• Thickener 0.2

Preservative 0.3

Stabilizer 0.5

Water at 100.

In this formulation, 3- (3,4-dichlorophenyl) -1,1-dimethylurea, 3- (4-chlorophenyl) -1,1-dimethylurea, 3- (3-chloro-4-methylphenyl) -1.1 were used in succession as stabilizers dimethylurea, 3- (3-bromophenyI) -I.1-dimethylurea, 3- (4-bromophenyl) -1-dimethylurea, 3- (4-methylphenyl) -1-dimethylurea and 3- (3- Chloro-4-methylphenyi) -1-methyl-l-ethyl urea; the salary was

* - 242354

2.2 wt. SS, based on Neburon.

In this formulation, the dispersant used was the phosphate of a polyarylphenol ethoxylated with about 18 moles of ethylene oxide.

This suspension was subjected to the same tests as in Example 1, using for comparison purposes an analogous suspension without stabilizing agent according to the invention. The results obtained are summarized in Table 2.

From the results, the same consequences as in Example 1, it being added that the stabilization is not changed by the presence of isoproturon.

Example 5

The procedure was as in Example 4, under otherwise identical conditions, the content of stabilizer was changed:

% Stabilizer,

based on the formulation 0.3 0.75 1 2 2.5

% Stabilizer,

based on Neburon 1,2 3 A 8 10.

Example 6

The procedure was as in Example 1, whereby a concentrated aqueous suspension of the following composition was prepared:

--- 2423 5 4

Wt X Neburon 20

isoproturon 15 bifenox 15 Antifreeze (glycol) 5 wetting agent 1.5 dispersants 1 Anti-foaming agents 0.3 thickener 0.2 preservative 0.3 stabilizer 0.5 water on 100.

In this formulation, sequentially used as stabilizers were 3- (3,4-dichlorophenyl) -II-dimethylurea, 3- (4-chlorophenyl) -II-dimethylurea, 3- (3-chloro-4-methylphenyl) -II-dimethylurea, 3- ( 3-bromophenyl) -II-dimethylurea, 3- (4-bromophenyl) -1-dimethylurea, 3- (4-methylphenyl) -II-dimethylurea and 3- (3-chloro-4-methylphenyl) -1-methyl-1 -ethylurea used, wherein the weight fraction was 2.5 wt .-%, based on neburon.

Example 7

The procedure was as in Example 1, wherein a concentrated aqueous suspension of the following composition was prepared:

Weight?

neburon (Glycol) 25 nitrofen 20 Antifreeze 5

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wetting agent on 3 dispersants 2 Anti-foaming agents 0.3 thickener 0.2 preservative 0.3 stabilizer 0.5 water 100th

In this formulation, 3- (3,4-dichlorophenyl) -II-dimethylurea, 3- (4-chlorophenyl) -l.ldimethylurea, 3- (3-8romphenyl) -l-dimethylurea, 3- (4-bromophenyl) -1.1 dimethyl urea, 3- (4-methylpheny1) -1,1-dimethylurea and 3- (3-chloro-4-methylphenyl) -1-methyl-1-ethylurea used; the content was 2% by weight, based on neburon.

Example 8

The procedure was as in Example 1, wherein a concentrated aqueous suspension of the following composition was prepared:

By weight of SS neburon 25 Atrazine or terbutryn 15 Antifreeze 5 wetting agent 2 dispersants 2 Anti-foaming agents 0.4 thickener 0.2 preservative 0.3 stabilizer 1 water on 100.

- 28 · -

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In this formulation, 3- (3,4-dichlorophenyl) -II-dimethylurea, 3- (4-chlorophenyl) -1,1-dimethylurea, 3- (3-chloro-4-niethyl-1-phenyl) -II-dimethylurea were used in succession as stabilizers , 3- (3-Bromophenyl) -II-diniethylurea, 3- (4-bromophenyl) -II-dimethylurea, 3- (4-methylphenyl) -II-dimethyl-urea, and 3- (3-chloro-4-methylphenyl) -

1-methyl-l-ethylurea used; the content was 4% by weight based on neburon.

Table 1

test Without stabilizer (prior art) t _o * 30 d at 50 ⁰ C G / D With stabilizing agent (according to the invention) t _{o +} 30 d at 50 ^° C G / D "--- ^ Zei tpunkt Art *" ^ _ O not pourable 13.5 sg 1.16-10 " ¹ 116 6.1 sg 2.18-10 " ² 21.8 3.15 sg 1.91-10 " ² 15,1 2,75 Self-dispersion dynamic viscosity (Pa s) (cP) mean diameter (pm) 2.73-ICf ² ; 27.3; ² ' ⁹ m '2.73 x 10 ~ ² 27.3 2.3

ro co cn yoke

Table 2

kind time viscosity Without stabilizer G / D With stabilizer t + 3Od G / D test (State of the art) m (inventive) i O at 50 ^° C. s.g. Self-dispersion Diameter (pm) 5.04 x 10 ~ ² s.g. 2.32-10 " ² dynamic (Pas) ! ^to 50.4 ¹ O 4.91-Kf ² 23.2 (CP) j s.g. 3.15 s.g. 49.1 2.65 middle 3,4-10 " ² 3.4 · 10 " ² 2.63 i 34 34 i ² ' ⁷ I 2.5 t _{o +} 30 d at 50 ^° C. O 2.18-lD " ¹ 218 4.1

Claims (17)

claims 1-10% by weight, based on the weight of the neburon, of a stabilizing agent of the formula I. NH-C-N (D. in which mean X, Y and Z are simultaneously or independently hydrogen, halogen or C 1 - to C 1 -alkyl, which is optionally halogenated, and
RC ₁ - to CyAlkyl. 1. Neburon-based herbicidal compositions in the form of concentrated aqueous suspensions containing neburon and optionally thickening agents, wetting agents and / or dispersants, marked by 2. Herbicidal compositions according to item 1, characterized by a stabilizing agent of the formula II 570 PH1981-00R-SF-Bk 24 2 35 y ι in which mean X ^{1 is} hydrogen, halogen or C ₁ - to C ^ -alkyl, Y 'is hydrogen, halogen or trifluoromethyl and
R ^{1 is} methyl or ethyl. 3. Herbicidal compositions according to item 2, characterized by a stabilizing agent of formula II, in which X 'is chlorine, bromine or methyl and
Y 'is hydrogen when X ^{1 is} chlorine or bromine, or chlorine or bromine mean. 4. Herbicidal compositions according to one of the points ^ _ L-3 to _r characterized by stabilizing agents of the formulas I or II in which the halogen atoms are chlorine atoms. 5. Herbicidal compositions according to item 4, characterized by 3- (3,4-dichlorophenyl) -l.l-dimethylurea as stabilizer. 6. Herbicidal compositions according to item 4, characterized by 3- (4-chlorophenyl) -ll-dimethylurea as stabilizer. 7. Herbicidal compositions according to item h, characterized by 3- (3-chloro-4-methylphenyl) -II-dimethylurea as stabilizer. Al - J - 242354 6 8. Herbicidal compositions according to one of the points _; ι to 7, characterized by 2-6 wt .-% stabilizer, based on the weight of the neburon. 9. Herbicidal compositions according to one of the items 1 to 8, characterized in that at least 95% by weight of the suspended solid particles have a diameter of less than 20 μm and at least 50% by weight have a diameter of less than 7 μm. 10. Herbicidal compositions according to one of. punjcte ι to 9, characterized in that they contain as active ingredient in addition to neburon at least one other herbicide. 11. Compositions according to item 10, characterized by isoproturon as a further herbicide. 12. Compositions according to item 10, characterized by nitrofen as a further herbicide. 13. Compositions according to item 10, characterized by Difenox as a further herbicide. 14. Compositions according to item 10, characterized by terbutryn or atrazine as further herbicide. 15. Process for the preparation of the aqueous concentrated suspensions based on neburon according to one of the items 1 to 14, marked by a) preparation of an aqueous solution containing the wetting agent and the dispersing agent, b) dispersing Neburon, optionally with additional herbicides, and the thickening agent in the resulting solution and  * 2423 5 4 5 c) comminution of the resulting dispersion by grinding. 16. The method according to item 15, characterized in that the thickening agent, if it is a biopolymer, is added to the comminuted dispersion in the form of a preservative-containing aqueous predispersion. 17. The method according to item 15, characterized in that the thickening agent, if it is an inorganic or mineral thickening agent, is added to the dispersion before comminution.