Plant protecting and regulating compositions – Antidotes
Reexamination Certificate
2000-10-24
2002-11-12
Clardy, S. Mark (Department: 1616)
Plant protecting and regulating compositions
Antidotes
C504S106000, C504S107000, C504S135000, C504S136000
Reexamination Certificate
active
06479432
ABSTRACT:
The invention relates to storage-stable non-aqueous or low-water suspension concentrates in the form of suspensions which comprise at least one solid, specifically from the group of the herbicidal sulfonylureas, dispersed in the organic phase, and surfactants, and other active compounds dissolved in the organic phase.
Herbicidally active compounds from the group of the sulfonylureas, such as, for example, the 1-[(hetero)aryl(oxy)sulfonyl]-3-pyrimidin-2-yl- or 1-[(hetero)aryl(oxy)sulfonyl]-3-(1,3,5-triazin-2-yl)ureas, are predominantly formulated in the form of water-dispersible powders (WP) or water-dispersible granules (WG). One reason why solid formulations are preferred is in most cases the pronounced sensitivity to hydrolysis of the active compounds of this substance class. Since, at the same time, they are relatively soluble in water, the development of liquid water-based formulations is extremely difficult if the chemical stability of the sulfonylurea is to be ensured. Thus, in the literature, storage-stable aqueous suspension concentrates (SC) (see EP-0514768) and aqueous suspoemulsions (SE) (see EP-0514769) comprising sulfonylureas have been described only for a few special cases. On the other hand, water-free liquid formulations of active compounds or active compound mixtures with suspended solids are frequently physically unstable. On storage, dispersed solids tend to form deposits or agglomerates, to change the viscosity of and/or to cause inhomogeneities in the preparation.
The preparation of liquid formulations of herbicidal sulfonylureas is of particular interest when these active compounds are to be combined with liquid adjuvants and/or dissolved active compounds which are to improve the use properties, for example the herbicidal action. Suitable dissolved active compounds which are additionally present in the preparation are, for example, one or more herbicidally active substances and/or one or more safeners having one or both of the two properties below:
1. The active compound to be combined with the sulfonylurea is an organic compound with a low melting point which cannot be formulated easily as wettable powder (WP) or water-dispersible granules (WG) with satisfactory use properties.
2. It is a substance whose activity in the formulation is enhanced, optimized or reliably reproducible when it is dissolved in an emulsifiable organic solvent or when it is combined with certain liquid or dissolved auxiliaries, so-called adjuvants.
A commercially important group of active compounds having the above properties is that of the substituted phenoxypropionic acid derivatives, for example of the heteroaryloxyphenoxy- or the phenoxyphenoxypropionic acid derivatives. Thus, for example, it is known that the activity of fenoxaprop-P-ethyl against important weed grasses is improved when, on application, sufficiently high amounts of a nonionic wetting agent, for example a fatty alcohol polyglycol ether (for example ®Genapol X-060, Clariant), are dissolved in the spray liquor. Furthermore, for use in crops of cereals, fenoxaprop-P-ethyl is usually employed with the crop-plant-protecting substance (safener, antidote) mefenpyr-diethyl, which has a very low melting point of 52-54° C. Owing to the abovementioned physical properties of the components, it is easily understood that the commercial combinations of fenoxaprop-P-ethyl/mefenpyr-diethyl are formulated in liquid form, either as emulsions in water (EW) or as emulsifiable concentrate (EC). Accordingly, clodinafop-propargyl, which belongs to the same class of active compounds as fenoxaprop-P-ethyl and has a melting point of 48.2-57.1° C., likewise has physical properties which are unfavorable for solid formulations. Combinations of this herbicide with the safener cloquintocet-mexyl are currently commercially available exclusively in the form of emulsifiable concentrates.
Further suitable active compounds which can be employed partially or completely dissolved in an organic solvent are, for example, also herbicides from the group of the hydroxybenzonitriles, such as ioxynil and bromoxynil and their commercial salts and esters. Alternatively, the further active compound different from the sulfonylurea can be a safener, without a further herbicide being present, or an active compound mixture of a further herbicide and a safener is added, where the additional active compounds are preferably substantially dissolved in an organic solvent.
In contrast to the abovementioned active compounds in liquid formulation, herbicides from the group of the sulfonylureas are, as mentioned, for reasons of stability in most cases formulated as wettable powders (WP) or water-dispersible granules (WG). However, EP-0313317 also discloses non-aqueous suspension concentrates for certain pyridylsulfonylureas where the active compound is suspended in a vegetable oil to increase the herbicidal activity and selectivity of the sulfonylurea. EP-0313317 does not discuss the chemical stability of the sulfonylurea in the formulation. Furthermore, formulations of herbicide mixtures and details which would allow the chemical or physical stability of herbicide combinations to be estimated are missing. In principle, the amount of dissolved active compounds in the organic phase can affect the stability of the suspension of the sulfonylurea. It is also generally known that a combination of active compounds in a coformulation can reduce the chemical stability of the active compounds (so-called incompatibility of the active compounds) or else reduce their biological availability or, in general, activity.
With respect to the combinations of sulfonylureas with active compounds from other structure classes, which, in most cases, are not formulated or cannot be formulated as granules or wettable powders, it was therefore the object to provide a liquid formulation for sulfonylureas which, with respect to the physical stability of the formulation, the chemical stability of the sulfonylureas and, if possible, also the biological activity of the sulfonylureas, is an alternative to or an improvement of the WP and WG formulations. It was another object to provide a stable liquid formulation which is compatible with the use requirements and the physical properties of all active compounds contained therein.
Surprisingly, it has now been found that storage-stable liquid, low-water or water-free formulations of sulfonylureas and one or more other active compounds can be prepared by dispersing (=suspending) the solid sulfonylurea in a solvent/sufractant mixture which comprises, in dissolved form, at least one further active compound.
Accordingly, the invention provides liquid preparations (formulations) in the form of suspension concentrates, which comprise
a) one or more solid herbicidally active compounds from the group of the sulfonylureas in suspended form,
b) one or more active compounds which are partially or completely dissolved in component c),
c) an organic solvent or solvent mixture,
d) one or more nonionic emulsifiers,
e) optionally one or more ionic emulsifiers,
f) optionally one or more thickeners or thixotropic agents and no water or up to 30 percent by weight of water in dissolved form.
The amount of sulfonylurea “in suspended form” means that the total amount of sulfonylurea or a part of the sulfonylurea is present undissolved in finely distributed form. Thus, it is also possible that part of the active compound is present in dissolved form. In the suspension concentrate, the sulfonylurea is preferably present substantially in undissolved form.
In addition, the suspension concentrates according to the invention may comprise the tackifiers, wetting agents, dispersants, penetrants, preservatives, antifreeze agents and solvents, fillers, carriers and colorants, antifoams, evaporation inhibitors and pH and viscosity regulators which are customary in each case. As long as they do not interfere; further emulsifiers, for example nonionic, anionic, cationic or amphoteric emulsifiers, may also be present, if appropriate.
Based on the formulations acc
Aventis CropScience GmbH
Clardy S. Mark
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