NL7908470A - HERBICIDE COMPOSITIONS. - Google Patents

Description

29/345-Fa / vdM

Herbicide compositions.

The invention relates to herbicide compositions and in particular to a herbicide composition in finely divided form.

In order to control a wide spectrum of weeds in 5 crops, it is often necessary to use more than one herbicide. Two well-known groups of herbicides can be described as dinitroaniline and urea herbicides, and among the former herbicides are those of formula 1, wherein R is C 2-4 alkyl or C 1-4 alkyl or C 1-4 alkenyl. Such dinitroanilines include, for example, 2,6-dinitro-NN-dipropyl-4-trifluoromethylaniline (trifluralin), N-ethyl-N- (2-methylallyl) -2,6-dinitro-4-trifluoromethylaniline (ethalfluralin) and N- butyl-N-ethyl-2,6-dinitro-4-trifluoromethylaniline (benfluralin). Both trifluralin and benfluralin are described in U.S. Patent 3,257,190 and ethalfluralin is the subject of British Patent 1,505,249.

Some of the more common ureas, long known for their herbicidal properties, are included in the formula 2, wherein R and R each are hydrogen, C 1-6 alkyl, C 1-6 alkoxy or are halogen and R and R are each C 1-6 alkyl or C 1-6 alkoxy, provided R 1 and R 2 are not both hydrogen.

It is often easy to provide the farmer with a concentrated solid mixture that requires only dispersion in water before it can be directly applied to the harvesting area. Such solid mixtures are safe to handle and their use presents less risk of incorrect calculation by the farmer of the herbicide equilibrium to be applied, which can occur when the two components are added separately to a large volume of water in a "tank mixture".

It has been found that due to the particular characteristics of the above-mentioned type of dinitroaniline and urea herbicides, solid compositions containing these products often have poor quality and tend to stick and form lumps, which makes them difficult to use in practice. These problems are especially evident when the product is stored at elevated temperatures even for very short periods. Liquid formulations, eg, aqueous suspensions, also suffer from lack of stability when stored at temperatures above normal temperatures.

The solid herbicide mixtures of the invention contain the active ingredients in association with certain silica derivatives which keep the composition in a flowing form. They have excellent herbicidal activity against a wide spectrum of weeds and have the added benefit of being usable in a mixing ratio that gives good weed control while still having the known tendency of urea herbicides to exert phytotoxicity on the harvest, is avoided. Accordingly, the invention provides a herbicide composition in finely divided form, consisting of an intimate mixture of (1) a dinitroaniline compound of formula 1, wherein R is C 1-6 alkyl and R is C 1-6 alkyl or C-alkenyl, ( 2) a urea compound of formula 2, wherein R 3 and R 4 are both hydrogen, C 1 -alkyl, C 1 -alkoxy or halo 5 6 1-4 and R and R are both C ...- alkyl or C-alkoxy, 3 41-4 1-4 provided that R and R are not both hydrogen and (3) a silica derivative selected from smoked silicon dioxide and precipitated silica.

An appropriate choice of the silica derivative must be made to avoid caking of the mixture. Not all silicon dioxides can be used for this purpose and the effectiveness of the silicon dioxide material does not only seem to depend on its physical properties but is also related to its 790 8470 3 chemical nature as the effect is limited to smoked or precipitated silicon dioxide.

Other silica materials commonly used in herbicide mixtures, such as precipitated silicates and micronized silica, are not effective for this purpose.

Smoked silicon dioxide is the oxidation product of silicon tetrachloride (SiCl 2), which is burned in an atmosphere of oxygen and hydrogen. The average particle diameter of the resulting material is generally between 2 and 50 millimicrons and the area between 175 and 2 400 m per gram, measured by the Brunauer, Emmett and Teller equation (J. Amer. Chem. Soc. 60 309 (1938)). Precipitated silica can be prepared by chemical reaction of an alkali metal silicate, such as, for example, sodium silicate, with a mineral acid, such as, for example, hydrochloric acid, followed by adjusting the pH until a precipitate forms. The precipitate is then separated, washed and dried. Its particle size is generally between 5 and 50 millimicrons and the area is between 50 and 2 350 m per gram. Both materials are well known in the art of assembly. E.g. smoked silica is commercially available as CAB-O-SIL H5 and as CAB-O-SIL M5 and precipitated silica as HiSlL 233, SILICA K320, UTRASIL VN3, WESSALON S and ZEOLEX 39 and 39A.

Preferably, the silica derivative is present in an amount of 2-40% by weight, more particularly of 4-15% by weight.

Preferably, the composition also contains a solid inert carrier, which may be any material known in the art for preparing solid herbicide compositions and these include, for example, kaolin, talc, montmorillonite, attapulgite, diatomaceous earth and hydrated sodium silicone aluminate. Most suitably, the mean particle diameter of the solid support within 7308470: 4. 4 ranges from 1-10 µm and the amount of the carrier in the mixture is preferably within the range of 0-85% by weight, more particularly from 5 to 50% by weight.

With regard to the herbicide components of the composition, a range of dinitroanilines can be used, preferably trifluralin, ethalfluralin and benflurlin, with trifluralin being of particular interest in this regard. The dinitroaniline herbicide is generally present in an amount of 10-50 wt%, such as 15-30 wt%.

As for the urea herbicide component, it is selected from compounds which are * included in formula 2.

3 4

For example, when R or R is C. alkyl, this is e.g. methyl, ethyl, 3, 4 propyl or butyl and when R or R is alkoxy it is e.g.

3 4 methoxy, ethoxy, propoxy or butoxy. When R or R is halogen, it is chlorine, bromine, iodine or fluorine, and preferably chlorine. R and R can have all meanings indicated for R and R when they are alkyl or alkoxy. The urea herbicide is preferably selected from metoxuron, chlorotoluron, isoproturon, linuron and neburon, with most preferred being metoxuron and it is conveniently present in amounts of 10-75% by weight, such as e.g. 20-60% by weight .% of the composition.

In formula 2 above, 3 has 4 5

(i) metoxuron the values R methoxy, R chlorine, R

6 methyl and R methyl; 3 4 (ii) chlorotoluron the values R methyl, R chlorine, 5 6 R methyl and R methyl; 3 (iii) isoproturon has the values R is isopropyl, 4 5 6 R hydrogen, R methyl and R methyl; 3 4 30 (iv) linuron has the values R chlorine, R chlorine, Rmethyl and Rmethyloxy; 3 4 (v) neburon has the values R chlorine, R chlorine, R5 methyl and R6 butyl.

It will be understood that more than one di-35-troaniline and / or urea herbicide can be used in the 790 84 70 9 composition of the invention.

The choice of the relative proportions of the active herbicides depends on the nature of the dinitroaniline and urea herbicide components, but generally the herbicides are used in a ratio range of 5: 1 to 1:20 by weight.

It has been found that the compositions of the invention have surprising stability and retain their finely divided form on storage, even at temperatures above those normally experienced. The finely divided particles of the solid support remain discretely despite the presence of the other ingredients of the mixture adhered thereto, and the resulting mixtures can be easily diluted with water for direct application to the crop by spraying and.

They also have the advantage over concentrated liquid mixtures that they have good stability at low temperatures.

For convenience, the composition of the invention is in the form known as "wettable powder" and then comprises a surfactant, such as a dispersant. Examples of suitable anionic surfactants are the alkyl and aryl sulfonates, sulfates and sulfosuccinates, such as isopropyl naphthalene sulfonates, dodecyl benzene sulfonates, dioctyl esters of sulfosuccinic acids, dinonyl sulfosuccinates, lauryl polyglycol ethersulfosuccinates, lauryl sulfosulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfyl sulfosuccinates Examples of suitable nonionic surfactants are polyoxyethylene sorbitan esters of mixed fatty acids and resin acids, such as polyoxyethylene sorbitan monolaurates, monopalmitates, monostearates, monooles, tristearates and trioleates, alkyl aryl polyethoxyethanols, such as nonyl and iso-octyl-phenyl-35 polyethoxyethanols, glyceride esters, such as diglyceryl mono 790 84 70 • η 6 oleate, glyceryl dioleate and glyceryl dilaurate, and ethoxylated alkyl phenols and cresols, such as ethoxylated octyl ethoxylated nonyl phenyl.

A preferred composition according to the invention contains 5-40 wt% trifluralin, 5-75 wt% metoxuron, 2-25 wt% silica derivative, 1-10 wt% wetting agent and 0-10 wt% a dispersant, the balance up to 100% by weight being an inert filler.

An object of the present invention is to provide a composition which has useful herbicidal properties when diluted with water.

The dinitroaniline component is especially active against grassy weeds, such as Poa annua, Apera spica-venti and Alopecurus myosuroides, while the urea component is more effective against broad-weed species, such as Capsella bursa-pastoris, Sinapis arvensis and Matricaria spp. This combination allows the use of urea herbicides in an amount which avoids their known tendency to exhibit phytotoxicity in the crop, while still providing excellent weed control.

A combination of the two types of herbicides makes it possible to control a wide spectrum of weeds related to grain harvests, such as eg wheat, barley, oats and rye and especially wheat and barley.

As a further aspect of the invention, it comprises a method of controlling weeds in a harvesting area, characterized in that an aqueous dispersion prepared by mixing a composition according to the invention with water is applied to the harvesting area.

The application of the dispersion can be carried out by any well-known spraying technique and at a stage before or after hatching, depending mainly on the urea herbicide used and the preferred purpose of use.

Generally, the blends are best used in post-hatching 7908470 operations. In a special case, a composition containing trifluralin and metoxuron can be applied before or after hatching, but it is preferably used after hatching, eg in grain harvests at the stage where the harvest is at the stage between the condition with 2 leaves and branches.

For convenience, the aqueous dispersion prepared from the mixture of the invention is used in such an amount that the dinitroaniline herbicide is applied in an amount of 200-1500 g / hectare. With respect to the urea herbicide, the application rate is preferably as follows: linuron in the range of 200-1000 g / hectare, neburon in the range of 2000-4000 g / hectare, chlorotoluron in the range of 1000-3000 g / hectare. 15 tare, isoproturon in the range 450-2000 g / adhesare and metoxuron in the range 1000-3500 g / adhesare. At such amounts administered, the active ingredients are generally diluted with 100-600 liters of water for applications per hectare.

In preparing the composition of the invention, a mixture is first made by adding the urea component and the silica derivative together and optionally adding a surfactant, an inert carrier and other excipients, eg 25 in a ribbon mixer or a bypass screw mixer. The dinitroaniline compound is then added to the mixture, preferably by spraying the molten material on it. It is then cooled and preferably ground in an air mill, a disc mill or a hammer mill, for example, to a material 30 with an average particle size of 0.5-50 µl, preferably 1-15 µl.

As a further embodiment of the invention, there is provided a process for the preparation of a herbicidal mixture, characterized in that a finely divided inert solid carrier is mixed with a silica dioxide 730 8 4 70 • 8 a vessel selected from fumed silica and precipitated silica and a urea compound of formula 2, after which a molten dinitroaniline compound of formula 1 is sprayed onto the resulting mixture at a temperature of 45-100 ° C, while continuing a thorough mixing operation, cooling the mixture so formed and is subjected to grinding at a temperature of 10-40 ° C to form a product having an average particle diameter of 1-15 µl. The invention is illustrated by the following examples.

EXAMPLE I

Kaolin was added to a ribbon mixer and the mixer was set in motion. Subsequently, precipitated silica, metoxuron, sodium alkyl sulfate and sodium lignin sulfonate were added in the amounts indicated below and a thorough mixture was achieved. Molten trifluralin was sprayed onto the rotating mixture of materials at a temperature of about 75 ° C.

After the addition was completed, the mixer 20 was stopped, the mixture collected, and allowed to cool. This coarse powder was exposed to the action of an air mill, the throughput being adjusted to obtain a finely divided powdered mixture having an average part diameter of 5 µx.

25 wt. % trifluralin 20 metoxuron 50 precipitated silica 8 sodium alkyl sulfate 2 30 sodium lignin sulfonate 6 kaolin to 100

Mixtures, prepared in a similar manner as described above, were prepared from the ingredients indicated in Examples II-XX below.

o 790 84 70 9

EXAMPLE II

* wt. % trifluralin 16 metoxuron 45 5 fumed silica 4 sodium alkyl ether sulfate 4 sulfonated lignin 2 talc to 100

EXAMPLE III

10 wt% ethalfluralin 18 metoxuron 50 precipitated silica 10 ethoxylated alkyl phenol 2 15 sodium salt of condensed naphthalene sulfonic acids 4 montmorillonite to 100

EXAMPLE IV

wt. % 20 benfluralin 14 metoxuron 42 smoked silica 7 sodium tridecyl sulfate 3 sulfite liquor 5 25 attapulgite to 100

EXAMPLE V

wt. % trifluralin 20 chlorotoluron 25 30 precipitated silica 10 sodium alkyl ether sulfate 4 sodium lignin sulfonate 2 kaolin up to 100 35 730 8 4 70 10

EXAMPLE VI

wt. % trifluralin 20 chlorotoluron 46 5 smoked silica 6 sodium lauryl sulfate 3 sulfite liquor 5 attapulgite to 100

EXAMPLE VII

10 wt% trifluralin 20 neburon 40 precipitated silica 8 ethoxylated alkyl phenol 2 15 sulfonated lignin 3 attapulgite to 100

EXAMPLE VIII

wt. % trifluralin 18 20 neburon 45 smoked silica 6 sodium lauryl sulfate 3 sulfite liquor - 5 talc to 100

EXAMPLE IX

wt. % trifluralin 24 linuron 12 precipitated silica 12 30 sodium lauryl sulfate 2 _ sulfonated lignin 4 attapulgite to 100 35 790 8 470

EXAMPLE X

> 11 wt% trifluralin 24 linuron 6 5 smoked silica 8 sodium tridecyl sulfate 5 sodium lignin sulfonate 3 kaolin to 100

EXAMPLE XI

10 wt% trifluralin 20 isoproturon 20 precipitated silica 6 sodium lauryl sulfate 6 15 sulfite liquor 2 talc to 100

EXAMPLE XII

wt% trifluralin 25 20 isoproturon 37.5 smoked silica 10 sodium dioctyl sulfosuccinate 2 sodium lignin sulfonate 6 attapulgite to 100

25 COMPARATIVE EXAMPLE

In this example, a number of silicon dioxide materials are used in the preparation of compositions containing the two active herbicide components trifluralin and metoxuron.

The ability of the mixture to resist caking and clumping when stored at elevated temperatures simulating storage conditions was measured by a 45 µm mesh sieve.

Each mixture contained 10 wt.% Silica and 7908470 ψ · 12 was subjected to the same preparation method and grinding so that in any case less than 0.2% of it was retained on the screen at the start of the test. The mixtures were stored at 60 ° C for one day and at 50 ° C for one week, and then the amount remaining on the screen was measured again. A value of less than 1% represents an acceptable product and it will be found that in most cases the mixtures of the invention, ie containing smoked or precipitated silica, exhibited a much lower value.

£% left on 45 µl sieve 1 day 1 week

15 60 ° C 50 ° C

ALUSIL N Precipitated Silicate 3.0 1.4 MICROCAL 160 Precipitated Silicate 6.8 2.6 ZEOLEX 29 Precipitated Silicate 2.0 1.4 GASIL 23 Micronized Silicon Dioxide 1.2 2.0 20 GASIL 200 Micronized Silicon Dioxide 30.2 18. 6 CAB-O-SIL H5 fumed silica 0.2 0.6 CAB-O-SIL M5. smoked silica 0.2 0.2 KISIL 233 precipitated silica 0.4 0.2 SILICA K320 precipitated silica 0.2 0.2 25 ÜLTRASIL VN3 precipitated silica 0.2 0.2 WESSALON S precipitated silica 0.2 0.2 ZEOLEX 39 precipitated silica 0.4 0.2 ZEOLEX 39A precipitated silica 0.2 0.6 30 790 8470

Claims (10)

Herbicide composition in finely divided form, characterized in that it contains intimately mixed 5 (1) a dinitroaniline compound of formula 1 2 1, wherein R is C 2-2 alkyl and R is C 1-6 alkyl or C 1-6 alkenyl, (2) a urea compound of formula 2, wherein in R and R 3 each is hydrogen, C 1 -alkyl, C 1 -alkoxy or halo-5 4 and R and R are each C 1 -alkyl or C 1 -alkoxy, 3 -1-4 1-4 provided that R and R are not both hydrogen and (3) a silica derivative selected from smoked silica and precipitated silica. Herbicide composition according to claim 1, characterized in that the dinitroaniline compound is trifluralin. Herbicide composition according to claim 1 or 2, characterized in that the urea compound is metoxuron, chlorotoluron, isoproturon, linuron or neburon. Herbicide composition according to claim 3, characterized in that the urea compound is metoxuron. Herbicide composition according to claims 1-4, characterized in that it comprises a solid inert carrier. Herbicide composition according to claims 1-5, characterized in that the dinitroaniline bond is present in an amount of 15-30% by weight. Herbicide composition according to claims 30 1-6, characterized in that the urea compound is present in an amount of 20-60% by weight. Herbicide composition according to claims 1-7, characterized in that the silicon dioxide derivative is present in an amount of 4-15% by weight. Herbicide composition according to claims 790 84 70 * 1-8, characterized in that it has an average particle diameter of 1-15 µl. Herbicide composition according to claim 1, characterized in that it contains 5-40 wt.% Trifluralin, 5-75 wt.% Metoxuron, 2-25 wt.% Silicon dioxide derivative, 1-10 wt.% Wetting agent and 0- Contains 10 wt% dispersant and the remainder up to 100 wt% inert filler. 10 790 84 70 N / 29.345-Fa / vD. Belongs to patent application t.n.v. Lilly Industries Limited, London, Great Britain. FORMULA SHEET R 'R * ° 9N - N02 ^ I' V CF3 / - \ R3 — A \ -NH — CO-1 / / == / 2 R6 è 790 84 70