Plant protecting and regulating compositions – Plant growth regulating compositions – Designated nonactive ingredient containing
Reexamination Certificate
2000-05-19
2001-07-03
Clardy, S. Mark (Department: 1616)
Plant protecting and regulating compositions
Plant growth regulating compositions
Designated nonactive ingredient containing
C514S939000
Reexamination Certificate
active
06255253
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to liquid concentrates of water-insoluble agricultural chemicals (hereinafter referred to agrochemicals) and to a process for producing these concentrates.
Agrochemicals such as, for example, biocides, herbicides, insecticides and even fertilizers contain organic compounds which are insoluble or poorly soluble in water. In order to convert these agrochemicals into a form in which they are easy to handle by the user, they are often marketed as concentrated solutions in suitable organic solvents, for example alkyl benzene. Before use, these solutions have to be further diluted to the required concentrations. However, the use of these organic solvents is undesirable for economic reasons and above all for ecological reasons. Accordingly, there is a need for water-based concentrates of the agrochemicals in question.
WO 95/28083 describes water-based surfactant mixtures containing an alkyl naphthalene sulfonate and alkyl (oligo)glycosides and at least one pesticide and optionally other agrochemicals. EP 511 611 B1 describes aqueous solutions of the herbicide glufosinate ammonium. It is also mentioned in the specification that the claimed solutions may also contain other water-insoluble constituents in emulsified form. However, only aqueous solutions of the herbicide are disclosed in the Examples.
The known water-based formulations often show performance-related disadvantages in practice. Thus, the emulsions can separate on dilution with water. This problem occurs in particular where electrolyte-containing water, for example tap water, is used for dilution because the salt ions can upset the hydrophilic/lipophilic balance of the emulsifiers at the water/oil interface. In addition, problems arise during storage at low temperatures, for example below 10° C., because in that case the emulsion often has to be rehomogenized before use.
Accordingly, the problem addressed by the present invention was to provide ecologically safe, low-temperature-stable aqueous emulsions of water-insoluble or substantially water-insoluble agrochemicals with virtually unlimited dilutability.
BRIEF SUMMARY OF THE INVENTION
It has been found that water-insoluble agrochemicals can be processed in the presence of selected emulsifier combinations to form microemulsions with the required properties.
Accordingly, the present invention relates to a liquid concentrate of an agrochemical in the form of a transparent oil-in-water microemulsion with a droplet size of essentially 10 to 100 nm which contains alkyl (oligo)glycosides corresponding to general formula (I):
R—O—[Z]
x
(I)
in which R is an alkyl group containing 8 to 22 carbon atoms, Z is a sugar unit containing 5 or 6 carbon atoms and x is a number of 1 to 10, as emulsifiers and optionally other auxiliaries and additives, characterized in that the oil phase contains a water-insoluble agrochemical and optionally an organic water-insoluble solvent.
DETAILED DESCRIPTION OF THE INVENTION
The microemulsions described herein are emulsions of the oil-in-water type. They are optically isotropic, thermodynamically stable systems which contain water-insoluble oils, emulsifiers and water. The clear or transparent appearance of the microemulsions is attributable to the small droplet size of the dispersed oils which is essentially below 300 nm, i.e. more than 50% and preferably more than 80% of the droplets are below 300 nm in size, fine-droplet microemulsions brown-red in transmitted light and a shimmering blue in reflected light being present in the range from 100 to 300 nm and substantially optically clear microemulsions being present in the particularly preferred range of 10 to 100 nm. The optical impression of the clear transparency is particularly good when the transmissivity of the emulsion for light with a wave length of 650 nm is at least 85%. The microemulsions according to the invention are stable over a broad temperature range of 0 to
50° C.
The concentrates according to the invention contain as oil phase the water-insoluble agrochemical and, optionally, a suitable water-insoluble solvent for that agrochemical. The agrochemical concentrates according to the invention contain the oil phase, i.e. agrochemical, solvent and optionally other auxiliaries and additives soluble or dispersible in the oil phase, in quantities of preferably 10 to 50% by weight. In the context of the present invention, the emulsifier does not count as part of the oil phase. The function of the solvent is above all to simplify handling of the partly inhalation-toxic agrochemicals because they are easier to process in solution. However, it has also been found that the stability of the emulsions can be improved by selected solvents.
Agrochemicals in the context of the present invention are substances which may be used for plant protection, but also herbicides and fertilizers. Agrochemicals also include insecticides, acaricides, nematicides, pesticides and also repellents or rodenticides, sexual attractants, mammal and bird repellents and chemosterilants as described, for example, in Chemie der Pflanzenschutz- und Schädlingsbekämp-fungsmittel, Vol. 1, Editor: R. Wegler, Springer-Verlag Berlin, 1970 and in The Pesticide Manual, World Compendium: 8th Edition, The British Crop Protection Council, 1987. The agrochemicals are insoluble in water. In the context of the present invention, this means a solubility in water at room temperature (21° C.) of less than 10% by weight and preferably less than 5% by weight. Agrochemicals with a solubility in water of less than 1% by weight are preferred. The agrochemicals may be solid or liquid at room temperature.
The agrochemical concentrates may contain mixtures of water-insoluble agrochemicals in any quantity ratios. They may also contain water-soluble compounds. However, concentrates free from water-soluble agrochemicals are preferred.
The concentrates preferably contain insecticides, for example from the group of chlorinated hydrocarbons, for example hexachlorocyclohexane derivatives or cyclodiene derivatives, pyrethrines, pyrethroids, N-isobutyl amides of unsaturated C
8-22
fatty acids, carbamates or phosphoric acid esters. A preferred insecticide is nonanoic acid methyl ester. Other preferred agrochemicals are insect repellents, for example 3-(N-n-butyl-N-acetylamino)-propionic acid methyl ester, N,N-diethyl caprylic acid amide or diethyl-m-toluamide. In another preferred embodiment, water-insoluble biocides, fungicides, herbicides or pesticides are present as agrochemicals.
The concentrates contain the water-insoluble agrochemicals in quantities of preferably 10 to 40% by weight and more preferably 15 to 30% by weight.
The solvents insoluble in water at room temperature (i.e. solubility below 10% by weight) are preferably selected from esters of C
12-22
fatty acids and primary C
1-4
alcohols, N,N-dimethyl amides or C
8-22
fatty acids, monohydric primary alcohols containing 12 to 24 carbon atoms, glycerol-C
8-22
-fatty acid esters of natural or synthetic origin and dialkyl ethers containing a total of 12 to 24 carbon atoms.
It has been found that the microemulsions according to the invention are formed particularly easily where a dialkyl ether containing a total of 12 to 24 carbon atoms is present in a quantity of at least 0.5% by weight as solvent for the agrochemicals. A mixture of a dialkyl ether containing a total of 12 to 24 carbon atoms and a monohydric primary alcohol containing 12 to 36 carbon atoms is an even better solvent.
Suitable dialkyl ethers are, in particular, those containing linear primary alkyl groups each having 6 to 12 carbon atoms, more particularly the symmetrical di-n-alkyl ethers, for example di-n-octyl ether. Preferred monohydric primary alcohols are liquid, single-branch alcohols such as, for example, 2-hexyl decanol or 2-octyl dodecanol. The dialkyl ether and the alkanol are preferably used in a ratio by weight of 9:1 to 7:3 as solvent.
Other preferred solvents are N,N-dimethyl decanoic acid amide and glycerol esters, preferably the monoesters and
Claas Marcus
Foerster Thomas
Wollenweber Horst-Werner
Clardy S. Mark
Cognis Deutschland GmbH
Drach John E.
Trzaska Steven J.
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