Title of Invention

STORAGE-STABLE, WATER-DILUTABLE FORMULATIONS OF HERBICIDALLY ACTIVE COMPOUNDS

Abstract

The invention relates to storage-stable, water-dilutable formulations of herbicidal compositions comprising at least one acid-labile and at least one base-labile herbicidally active compound. In addition to further auxiliaries, these formulations also comprise basic silicate on which the acid-labile active compound is adsorbed, and hydrophilic silicic acid, on which the base-labile active compound is adsorbed.

Full Text

The invention relates to storage-stable, water-dilutable formulations comprising at least one acid-labile and at least one base-labile herbicidally active compound. Herbicidal agents - like other crop protection agents - are usually not applied as pure active compounds, but together with various auxiliaries in the form of a so-called formulation. The auxiliaries which are employed for this purpose, such as inert materials, dispersants, wetting agents and solvents, are to ensure, in addition to good action, also the simple use of the herbicidal agents. When controlling undesirable plants in crops of useful plants, it is a frequent problem that the individual commercially available herbicidal agents are not sufficiently active. To obtain an optimum effect, a combination of several types of herbicidaliy active compounds in one composition is in many cases desirable. However, it is known that many herbicidaliy active compounds can often not be combined in one composition, since they have different stabilities towards the formulation conditions. It is particularly problematic to combine acid-labile active compounds with base-labile active compounds in a composition suitable for application. Numerous compounds from the group of the sulfonylureas (group A) and organophosphoric acid derivatives (group B) are herbicidaliy active compounds which complement each other In an outstanding manner in the control of undesirable plants in crops of useful plants, in particular in rice crops. However, the active compounds of these two groups are not stable in a common formulation under customary formulation conditions, because the active compounds of group A decompose under acidic conditions and the active compounds of group B decompose under basic conditions. Usually, these two types of active compounds can only be applied separately - with the corresponding expense of time and cost. A combination of the two types of active compound in one storage-stable formulation suitable for application is desirable. Formulations which are suitable for application are, for example, those which, such as wettable powders or water-dispersible granules, can be made ready for use by simple mixing with water. WO 97/20467 discloses storage-stable formulations in which acid- and base-labile herbicidally active compounds are combined. This publication specifically describes storage-stable formulations of sulfonylureas and organophosphoric acid derivatives. The stabilization of active compounds which are incompatible per se In a common formulation is achieved here by using hydrophobic silicic acids as carrier material. However, these formulations have the disadvantage that they cannot be provided in water-dilutable form owing to the use of such hydrophobic silicic acids. It is therefore an object of the invention to provide storage-stable formulations which are suitable for use and comprise at least one acid-labile and at least one base-labile herbicidally active compound. This object is achieved by storage-stable, water-dilutable formulations of at least one acid-labile (component A) and at least one base-labile herbicidally active compound (component B). These formulations comprise a) basic silica or basic alkali metal silicate or alkaline earth metal silicate and b) hydrophilic, finely divided, approximately neutral silicic acid having a low water content. A further feature of the formulations according to the invention is the separate pre-treatment of the two components A and B, which are not stable under customary formulation conditions. The acid-labile component A is pre-treated with suitable auxiliaries to give a mixture MA, and the base-labile component B is also pre-treated with suitable auxiliaries to give a mixture MB. To prepare the mixture MA, component A and an oil are processed to a fine dispersion using an apparatus exerting very high shear forces. This dispersion is subsequently mixed with a basic silica (SiO2) or a basic alkali metal or alkaline earth metal silicate, so that the dispersion is adsorbed to this inert material. To prepare the mixture MB, component B is dissolved in a high-boiling organic solvent, and this solution is mixed with hydrophilic, finely dispersed, approximately neutral silicic acid (also referred to as "hydrophilic silicic acid" hereinbelow), so that the solution is adsorbed on the hydrophilic silicic acid. The resulting adsorbate is subsequently mixed with customary dispersants and wetting agents. The mixtures MA and MB can then be processed jointly in a customary manner by grinding to give water-dilutable wettable powders or by granulation to give water-dispersible granules. Oils suitable for preparing the dispersion comprising component A are those from the group of the mineral and vegetable oils. Preference is given to using epoxidized vegetable oils, such as epoxidized linseed oil and epoxidized soya oil, particularly preferably epoxidized soya oil. It is, of course, also possible to use a mixture of these oils. In the terminology hereinbelow, the term "oil" is therefore to be understood as an oil mixture or a single oil. Component A and oil are processed to a fine dispersion by allowing very high shear forces to act on the mixture of these substances. Methods to exert very high shear forces are known to the person skilled in the art. They can be generated, for example, by • intensive stirring or • shearing using a rotor-stator system The resulting dispersion is subsequently mixed in a suitable stirring apparatus with a basic silica, alkali metal silicate or alkaline earth metal silicate, in each case having a pH of from 8.5 to 11, preferably from 10 to 11 (measurement in accordance with DIN ISO 787/1X, ASTM D1208 or JIS K5101/24). Suitable basic silicas and/or silicates are, for example, the products obtainable under the trade names Durosil®, Extrusil® (both from Degussa AG, Germany) and Carplex®1120 (Shionogi & Co., Ltd., Japan), preference is given to Carplex®1120. These substances are employed in such amounts that their weight ratios, in each case based on the amount of component A, are usually as follows: To prepare the mixture MB, component B is dissolved with heating in an organic solvent. Solvents suitable for this purpose are in principle all high-boiling inert solvents which are capable of dissolving component B, for example those from the group of the aromatic hydrocarbons, mixtures of substituted aromatic hydrocarbons, such as the products available under the trade names Solvesso®200 (Exxon Corp., USA) and SAS 296 (Nihon Sekiyu Kagaku, Japan), and chlorinated aromatic hydrocarbons, such as chlorobenzene. Of course it is also possible to employ a mixture of these solvents. In the terminology hereinbelow, the term "solvenf is therefore to be understood as a solvent mixture or a single solvent. Preference is given to aromatic hydrocarbons and to mixtures of aromatic hydrocarbons. The hot solution comprising component B is then mixed with hydrophilic silicic acid having a pH of from 5.5 to 8, preferably from 6 to 7.5, and a water content of from 2 to 8% by weight, preferably from 3 to 6% by weight. Examples of preferred silicic acids are the products available from Quingdao Native Soda Plant, China and from Nanjing Tianmin Chem. Industries Co. Inc., China, and the products available under the trade names Carplex® CS 5, Carpiex® CS 7 (Shionogi & Co., Ltd., Japan), Wessalon® S (Insilco Corp. Bombay, India) and FK 500 LS (Degussa AG, Germany). This mixture is subsequently admixed with those dispersants and wetting agents which are customarily employed for preparing wettable powders and water-dispersible granules. These dispersants and wetting agents are described, for example, in: McCutcheon's "Detergents and Emulsifiers Manual", MC Publ. Corp., Ridgewood N.J.; Schonfeldt, "Grenzflachenaktive Athylenoxidaddukte", Wiss. Verlagsgesellschaft, Stuttgart 1976; Sisley and Wood, "Encyclopedia of Surface Active Agents", Chem. Publ. Co. Inc., N.Y. 1964; Winnacker-Kuchler, "Chemische Technologie", Volume 7, C. Hauser Verlag Munich, 4th edition 1986. Examples of dispersants are calcium lignosulfonates, sodium polycarboxylates and sodium salts of naphthalenesulfonic acid/formaldehyde condensates. Preference is given to the calcium lignosulfonates available under the trade names Newkalgen® RX-B (Takemoto Oil and Fat Co., Ltd., Japan) and Vanispense®CB (Borregard, Norway). Examples of wetting agents are in each case the sodium salts of diisobutylnaphthalenesulfonic acid, N-methyl-N-oleyltaurine, a-Ci4-Ci8-alkenesulfonic acids and isodecylsulfosuccinic acid half-ester. Preference is given to the sodium salt of N-methyl-N-oleyltaurine, which is obtainable under the trade name Hostapon®R (Hoechst AG, Germany). These substances are employed in amounts such that their weight ratios, in each case based on the amount of component B, are usually as follows: The values in brackets are the preferred weight ratios. The further processing to give wettable compositions and granules is carried out by mixing the mixtures MA and MB and subsequent grinding and granulation, respectively, in a manner known to the person skilled in the art. Such known methods are described, for example, in: K. Martens, "Spray Drying Handbook", 3rd edition, G. Goodwin Ltd., London, 1979; W. van Valkenburg, "Pesticide Formulations", Marcel Dekker, N.Y. 1973; Winnaker-Kuchler, "Chemlsche Technologie", Volume 7, C. Hauser Veriag Munich, 4th edition 1986; "Perry's Chemical Engineer's Handbook", 5th edition, McGraw-Hill, N.Y. 1973, pages 8-57. The mixing ratio of mixtures MA and MB should be chosen such that component A is present in the finished formulation at a content of from 0.1 to 10% by weight, preferably from 0.5 to 5% by weight, and component B is present at a content of from 10 to 40% by weight, preferably from 20 to 32% by weight. The contents of the remaining formulation constituents resulting from this data and from the data for mixtures MA and MB are, expressed in % by weight, as follows: The values in brackets are the preferred weight ratios. The ranges of the percentages by weight mentioned above and also hereinbelow are of course to be understood such that the sum of all constituents of a formulation is 100%. If desired, the application spectrum of the formulations according to the invention can be widened by addition of further active compounds, in particular herbicides and insecticides. If the active compound in question is acid-labile, it is preferably prepared together with component A to give mixture MA. It is of course also possible to prepare the active compound in a separate step in a manner similar to component A. If the active compound is base-labile, it is preferably prepared together with component B to give mixture MB. It is of course also possible to prepare this compound in a separate step in a manner similar to component B. If the active compound is neither acid- nor base-labile, it is preferably added to the mixtures MA and MB and, together with these, processed to give the desired formulation. The content of this active compound is usually in a range of from 0.5 to 10% by weight, based on the finished formulation. The method described above is suitable for processing a large number of acid- and base-labile active compounds to give a storage-stable formulation. Suitable components A are in particular herbicidally active compounds from the group of the sulfonylureas of the formula I R' is ethoxy, propoxy or isopropoxy R is fluorine, chlorine, bromine, iodine, nitro, cyano, trifluoromethyl, methyl, ethyl, propyl, isopropyl, methoxy, ethoxy, propoxy or isopropoxy, R and R independently of one another are hydrogen, chlorine, methyl, ethyl, methoxy or ethoxy, Z is CH or N and n is 0, 1, 2 or 3. A very particularly suitable compound is 3-(4,6-dimethoxypyrimidin-2-yl)-1-(2-ethoxyphenoxysulfonyl)urea (common name: "ethoxysulfuron"). These sulfonylureas are usually employed in the form of the alkali metal, alkaline earth metal or ammonium salt, preferably as alkali metal salt, particularly preferably as sodium salt. Suitable components B are in particular herbicidally active compounds from the group of the organophosphoric acid derivatives of the formula II R is hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, cyclopentyl or cyclohexyl, R is phenyl which may be substituted by one or two identical or different radicals selected from the group consisting of fluorine, chlorine, bromine, methyl and methoxy, R and R together with the linking nitrogen atom form a 5- or 6-membered saturated ring without substitution or with substitution by one or two methyl groups, R is methyl, ethyl, propyl or isopropyl and X is oxygen or sulfur. A very particularly suitable compound is S-4-chloro-N-isopropylcarbaniloylmethyl 0,0-dimethyl dithiophosphate (common name: "anilofos"). The examples below illustrate the invention. EXAMPLES In the examples according to the invention E1, E2 and E3 and in the comparative examples C1 and C2, the components A and B were processed together with auxiliaries to give water-dilutable wettable powders. To determine the storage stability, these wettable powders were stored for 3 months at 40°C or for 1 month at 50°C. According to experience, these storage conditions simulate a storage of two to three years under conditions customary in practice. Directly after the preparation and in each case after storage for one week, one month, two months and three months, samples were taken and their content of components A and B was determined. The content is expressed as degree of composition in per cent based on the content immediately after the preparation of the formulations. The content was determined by HPLC. EXAMPLE E1 Preparation of the mixture MA 1.1 parts (by weight) of the sodium salt of 3-(4,6-dimethoxypyrimidin-2-yl)-1-(2-ethoxyphenoxysulfonyl)urea are mixed with 5 parts of epoxidized soya oil and processed to give a dispersion. This dispersion is subsequently intensively mixed with 8.5 parts of a basic silica of type Carplex®1120. Preparation of the mixture MB The hot solution of 25 parts of S-4-chloro-N-isopropylcarbaniloylmethyl 0,0-dimethyl dithiophosphate and 10.7 parts of Solvesso®200 is added to 35.7 parts of a hydrophilic silicic acid of type Carplex®CS 7, and the mixture is mixed intensively. 12 parts of the dispersant Newkalgen®RX-B and 2 parts of the wetting agent Hostapon®T are added, and the mixture is again intensively mixed. Preparation of the wettable powder The two mixtures MA and MB are intensively mixed with each other and subsequently ground in a commercial pin mill to give a wettable powder. The examples according to the invention E2 and E3, like the comparative examples C1 and C2, were carried out in a similar manner. However, the two lastmentioned examples contain neither basic silica nor basic alkali metal silicate or alkaline earth metal silicate. Tables 1 and 3 show in each case the kind and the amount of the substances used. In comparative example C3, a commercial formulation was prepared by intensively mixing and subsequently grinding the substances given in Table 5. In the tables, the abbreviations denote: 1W: after storage for one week 1M 2M 3M after storage for one month after storage for two months after storage for three months not measured As is evident from the measured values given in Tables 2, 4 and 6, the formulations according to the invention have a considerably higher storage stability than the known formulations. WE CLAIM: 1. A storage-stable, water-dilutable formulation of at least one acid-labile (component A) and at least one base-labile herbicidally active compound (component B), which comprises a) basic silica or basic alkali metal or alkaline earth metal silicates and b) hydrophilic, finely divided, approximately neutral silicic acid having a low water content. 2. The formulation as claimed in claim 1, which comprises, as component A, a compound from the group of the sulfonylureas and, as component 6, a compound from the group of the S-(N-alkylcarbaniloylmethyl)-dithiophosphoric acid derivatives. 3. The formulation as claimed in claim 1 or 2, which comprises, as component A, 3-(4,6-dimethoxypyrimidin-2-yl)-1-(2-ethoxyphenoxysulfonyl)urea and, as component B, S-4-chloro-N-isopropylcarbaniloylmethyl) 0,0-dimethyl dithiophosphate. 4. The formulation as claimed in any of claims 1 to 3, wherein the component A is present in the form of its alkali metal, alkaline earth metal or ammonium salt. 5. The formulation as claimed in any of claims 1 to 4, wherein the hydrophilic silicic acid has a pH of from 5.5 to 8.5 and a water content of from 2 to 8% by weight. 6. The formulation as claimed in any of claims 1 to 5, wherein the basic silica, alkali metal silicate or alkaline earth metal silicate has a pH of from 8.5 to 11.5. 7. The formulation as claimed in any of claims 1 to 6, which comprises, as further auxiliaries, oil, organic solvent, dispersant and wetting agent. 8. The formulation as claimed in any of claims 1 to 7, which comprises 0.1 -10% by weight of component A, 10 - 40% by weight of component B, 1 -10% by weight of oil, 3-15% by weight of basic silica and/or basic alkali metal silicate or alkaline earth metal silicate, 4 - 20% by weight of solvent, 20 - 40% by weight of hydrophilic silicic acid, 8 -17% by weight of dispersant and from 0.5 to 5% by weight of wetting agent. 9. The formulation as claimed in claim 8, which comprises 0.5 - 5% by weight of component A, 20 - 32% by weight of component B, 2 - 7% by weight of oil, 5 -10% by weight of basic silica and/or basic alkali metal silicate or alkaline earth metal silicate, 4-15% by weight of solvent, 24 - 35% by weight of hydrophilic silicic acid, 10 -15% by weight of dispersant and firom 1.0 to 3% by weight of wetting agent. 10. The formulation as claimed in any of claims 1 to 9, which comprises a further active compound from the group consisting of herbicides and Insecticides. 11. The formulation as claimed in claim 10, wherein the content of this further active compound is 1 -10% by weight, based on the total amount of the formulation. 12. A process for preparing a formulation as claimed in any of claims 1 to 11, which comprises a) preparing a mixture MA by adsorption of a dispersion comprising component A and an oil on basic silica or basic alkali metal silicate or alkaline earth metal silicate, b) preparing a mixture MB by adsorption of a solution comprising component B and organic solvent on hydrophilic silicic acid and subsequent mixing with dispersants and wetting agents, and c) mixing the two mixtures MA and MB and processing the mixture by grinding to give a water-dilutable wettable powder, or by granulation to give water-dispersible granules.

Documents:

1961-mas-1998 abstract duplicate.pdf

1961-mas-1998 abstract.pdf

1961-mas-1998 claims duplicate.pdf

1961-mas-1998 claims.pdf

1961-mas-1998 correspondence-others.pdf

1961-mas-1998 correspondence-po.pdf

1961-mas-1998 description (complete) duplicate.pdf

1961-mas-1998 description (complete).pdf

1961-mas-1998 form-19.pdf

1961-mas-1998 form-2.pdf

1961-mas-1998 form-26.pdf

1961-mas-1998 form-3.pdf

1961-mas-1998 form-4.pdf

1961-mas-1998 form-6.pdf

1961-mas-1998 others.pdf

1961-mas-1998 petition.pdf