AU734653B2 - Dispersion agent for granules which contain water-insoluble agrochemical agents - Google Patents

Description

Dispersion Agent for Granules Which Contain Water-Insoluble Agrochemical Agents The present invention relates to granules which, in addition to water-insoluble agrochemical agents and, if appropriate, other auxiliaries, comprise a certain copolymeric dispersion agent, to the use of certain copolymers as dispersion agents in such granules and to a process for protecting plants against pests.

Water-insoluble agrochemical agents, such as, for example, fertilisers, herbicides, pesticides, insecticides or seed dressings, can be employed in a large number of formulations. These include, for example, aqueous dispersions or solutions in suitable organic solvents. The agents can also be prepared in the form of sprays or pastes. They can also be employed in solid form, for example as dusts in a mixture with suitable extenders, such as ground minerals, in the form of tablets or as granules. The latter formulation is particularly suitable, since it affords highly concentrated preparations which are storage-stable and easy to handle. Shortly before the actual use, the granules are dispersed in water, and the user can adjust the concentration predetermined for the particular intended use.

In addition to the actual agent or agent mixtures, these granules usually also comprise fillers and/or carriers and other auxiliaries. Such granules can be prepared either by impregnation of a suitable porous carrier with the liquid agent (or a liquid formulation of a solid agent), for example by spraying the agent onto the porous carrier material, or by granulating the agent with suitable carriers and auxiliaries in the presence of an auxiliary liquid, for example water. When preparing such granules, use is also made of extruders resulting in the mixture to be granulated being exposed to high pressures. In this case, it is frequently observed that the granules are no longer water-dispersible in sufficient quantities. Thus, when preparing highly concentrated granules, and in particular in the case of granules prepared by extrusion, auxiliaries, for example anionic surfactants, are added to improve the dispersion of the granules R. Wegler, Chemie der Pflanzenschutz- und Schadlingsbekampfungsmittel [Chemistry of Crop Protection Agents and Pesticides], Springer-Verlag, S1970, Volume 1, pages 41 to 54).

"However, even these dispersant-containing granules do not meet all the requirements of easy dispersibility. Accordingly, it was the object of the present application to provide auxiliaries to improve 30 the dispersion of water-insoluble agrochemical agents used in the form of granules.

It has been found that certain copolymers are highly suitable dispersion agents for these granules.

Accordingly, the invention provides, in a first embodiment, granules comprising at least one waterinsoluble agrochemical agent (solubility at 20°C max. 0.lwt%/L) and a polymeric dispersion agent :and, if appropriate, other auxiliaries, wherein the polymeric dispersion agent is a copolymer preparable by polymerisation of a) 1 to 99wt% of free-radically polymerisable, ethylenically unsaturated acids and/or their anhydrides b) 99 to 1wt% of free-radically polymerisable, ethylenically unsaturated esters and, if appropriate, c) 0.5 to 20wt% of other free-radically polymerisable comonomers.

To prepare the granules according to the invention, it is possible to use all granulation processes known to the person skilled in the art, as described, for example, in Hagers Handbuch der -AO C08238 pharmazeutischen Praxis [Handbook of Pharmaceutical Practice], Springer Verlag, Volume 2, 1991, pages 724 to 742. Granules obtained by extrusion are particularly suitable.

Agrochemical agents are understood as meaning those chemical compounds which are used in the field of agriculture. These include, in particular, crop protection agents and pesticides (R6mpp Chemie Lexikon, Volume 6, 9 h Edition, 1991, page 3323). Examples of suitable compounds are given in the book by R. Wegler referred to above. However, only those compounds are selected which are not or only sparingly soluble in water at room temperature ie. those which, at room temperature, have a solubility of at most 0.1wt% in one litre of water. Particular preference is given to granules which comprise, as active compounds, crop protection agents, for example compounds from the groups consisting of the acaricides, algicides, aphicides, bactericides, fungicides, herbicides, insecticides, molluscicides, nematicides, rodenticides and virucides.

Suitable water-insoluble agrochemical agents can be both solid and liquid at room temperature however, solid agents are preferred from an applications-related standpoint and particularly suitable for use in granules. Particular preference is given to water-insoluble agents from the classes of the 1i nitrophenol derivatives, phosphoric acid esters, phenylurea or phenylthiourea derivatives, triazines, dimethylmorpholines, diphenyl sulfones, methyl carbamates, naphthyl carbamates, piperonylurea derivatives, thiophosphates or trichloroethane derivatives.

The granules according to the invention comprise the water-insoluble agrochemical agent preferably in amounts between 0.5 and 90wt%. However, particular preference is given to granules having a high proportion of active compounds, preferably between 30 and The polymeric dispersion agents in the granules according to the invention are compounds which are known per se. Thus, EP 372 746 Al describes copolymers of acrylic acid or methacrylic acid with esters of acrylic or methacrylic acid with long-chain alcohols. However, these are only described for use as hydrophobicisation agents for finishing leather. DE 4129244 Al discloses copolymers of monoesters of maleic acid with oleophilic alcohols and acrylic acid and/or methacrylic acid and, if appropriate, other comonomers which can be used in the form of aqueous dispersions as auxiliaries for fat-liquoring finishing of leather and furs. DE 4223111 Al describes copolymers of fatty crotonates and maleic acid or maleic anhydride and their use for finishing leather. None of the documents quoted describes the use of such copolymers in crop protection agents or as dispersion agents.

The copolymers used in the granules according to the invention can be prepared by all known processes for free-radical polymerisation. Customarily, the monomers are dissolved in water and a polymerisation reaction is then initiated by addition of suitable free-radical initiators or by UV light.

The copolymers are prepared by simultaneous reaction of at least two different monomer building blocks a) and b) and, if appropriate, c).

The monomers of group a) are free-radically polymerisable, ethylenically unsaturated, preferably monounsaturated, acids and/or their anhydrides. Suitable monomers are organic carboxylic acids having 3 to 10 carbon atoms, for example acrylic and methacrylic acid, crotonic acid, Smaleic and fumaric acid or anhydrides thereof. It is also possible to use mixtures of the component a) C08238 as monomers. Particular preference is given to comonomers whose monomer building block a) is selected from the group consisting of acrylic acid, methacrylic acid, maleic acid and maleic anhydride.

Free-radically polymerisable, ethylenically unsaturated esters are used as monomer building block Suitable acid components are the mono- and dicarboxylic acids mentioned under a), esterified with alcohols having 1 to 40 carbon atoms. Particular preference is given to compounds obtained by esterifying acrylic, methacrylic, crotonic or maleic acid with fatty alcohols of a chain length of from C 12 to C 22 Among the esters of the dicarboxylic acids, both the mono- and the diesters are suitable. However, particular preference is given to copolymers which, as monomer comprise monoesters of maleic acid with fatty alcohols having 12 to 22 carbon atoms.

In addition to the monomers a) and the copolymers may also comprise minor amounts of monomers of group These are compounds known to the person skilled in the art which can be polymerised by free-radical polymerisation. Examples of such compounds are on the one hand compounds containing ethylenic double bonds, such as vinylsulfosuccinic acid, and on the other hand also polymerisable silanes, such as trimethoxychlorosilane. Preferred dispersion agents for the granules according to the invention are copolymers which, in addition to the monomers a) and also comprise trimethoxychlorosilane.

The copolymers are constructed from the stated amounts of monomers b) and, if appropriate, Preference is given to granules which, as dispersion agents, are constructed copolymers comprising 5 to 50wt% based on the copolymer of the monomers a) and 95 to of the monomers In the case of polymers which additionally also comprise monomer building blocks of group these monomer building blocks are preferably present in amounts between 1 and The granules according to the invention comprise the polymeric dispersion agent preferably in amounts between 1 and 50wt%, and granules comprising between 5 and 15wt% of the dispersion agent are particularly suitable.

The granules may also comprise auxiliaries. These include, for example, fillers or carriers, surfactants or other dispersion agents. As filler or carrier, the granules may comprise all compounds known to the person skilled in the art as being suitable. These include, for example, clay minerals, such as zeolites or bentonites, silica gel or organic and inorganic salts. Preference is given to granules which, as filler or carrier, comprise sodium sulfate or sodium citrate. The filler or carrier is preferably present in the granules in amounts between 1 and Suitable surfactants are anionic, nonionic and/or cationic surfactants. Preferred anionic surfactants are fatty alcohol sulfates, naphthalene sulfonates or lignosulfonates. However, the granules according to the invention are preferably free of surfactants. In addition to the compounds already mentioned, the granules may also comprise other suitable auxiliaries and additives, such as disintegrants, binders, defoamers, colorants and/or perfumes.

Preparation of the granules according to the invention can be carried out using granulation processes known in the prior art. Particular preference is given to granules which are prepared by extrusion. To this end, the agrochemical agents are mixed with a dispersion agent and, if appropriate, fo)/ with other auxiliaries, shaped into a compressible material and then extruded by application of C08238 pressure, the dispersion agents used being copolymers of the type described above. The extruded material leaving the extruder is cut by rotating knives to give the granules proper. The extrusion is preferably carried out at pressures between 2 and 200bar, in particular at pressures of from 5 to 150bar. The resulting granules have particle sizes between 0.01 and 5.0mm, preferably between and The granules according to the invention are storage-stable and can easily be dispersed in water. In general, the granules can be dispersed by use of slight shear forces for example by simple stirring by hand. However, depending on the agents used, it may also be necessary to disperse the granules using suitable aids, for example a mechanical stirrer.

Also claimed is the use of copolymers of the type described above as dispersion agents for granules which comprise water-insoluble agrochemical agents and, if appropriate, other auxiliaries.

The present application also provides a process for protecting plants, where granules of the type described above are dispersed in water and this dispersion is applied to the plants.

C08238

Claims (16)

1. Granules comprising at least one water-insoluble agrochemical agent (solubility at max. 0.1wt%/L) and a polymeric dispersion agent and, if appropriate, other auxiliaries, wherein the polymeric dispersion agent is a copolymer preparable by polymerisation of a) 1 to 99wt% of free-radically polymerisable, ethylenically unsaturated acids and/or their anhydrides b) 99 to 1wt% of free-radically polymerisable, ethylenically unsaturated esters and, if appropriate, c) 0.5 to 20wt% of other free-radically polymerisable comonomers.

2. Granules as claimed in claim 1, wherein the polymeric dispersion agent is a copolymer preparable by polymerisation of from 5 to 50wt% of a monomer from 95 to 50wt% of a monomer b) and, if appropriate, from 1 to 5wt% of a monomer c).

3. Granules as claimed in claim 1 or claim 2, wherein the polymeric dispersion agent is a copolymer whose monomer a) is selected from the group consisting of acrylic acid, methacrylic acid, maleic acid and maleic anhydride.

4. Granules as claimed in any one of claim 1 to 3, wherein the polymeric dispersion agent is a copolymer whose monomer b) is selected from the group consisting of the esters of acrylic, methacrylic, crotonic or maleic acid with alcohols having 1 to 40 carbon atoms.

Granules as claimed in claim 4, wherein the alcohol have 10 to 22 carbon atoms.

6. Granules as claimed in any one of claim 1 to 5, wherein the polymeric dispersion agent is a copolymer whose comonomer c) is trimethoxychlorosilane.

7. Granules as claimed in any one of claims 1 to 6, which comprise the polymeric dispersion agent in amounts of from 1 to

8. Granules as claimed in claim 7, which comprise the polymeric dispersion agent in amounts of from 5 to

9. Granules as claimed in any one of claims 1 to 8, which comprise, as water-insoluble 25 agrochemical agent, crop protection agents.

Granules as claimed in any one of claims 1 to 9, which comprise the water-insoluble agrochemical agents in amounts between 0.5 and

11. Granules as claimed in any one of claims 1 to 10, wherein the auxiliaries are carriers or extenders selected from the group consisting of sodium sulfate and sodium citrate. 30

12. Granules as claimed in any one of claims 1 to 11 which comprise the carrier or extender in amounts between 1 and o:

13. Granules as claimed in any one of claims 1 to 12, which are prepared by extrusion.

14. Granules comprising at least one water-insoluble agrochemical agent (solubility at max. 0.1wt%/L) and a polymeric dispersion agent and, if appropriate, other auxiliaries, said granules 35 being substantially as hereinbefore described.

The use of copolymers preparable by polymerisation of a) 1 to 99wt% of free-radically polymerisable, ethylenically unsaturated acids and/or their anhydrides 71N b) 99 to 1wt% of free-radically polymerisable, ethylenically unsaturated esters and, if appropriate, c) 0.5 to 20wt% of other free-radically polymerisable comonomers C08238 as dispersion agents in granules which comprise at least one water-insoluble agrochemical agent (solubility at 20 0 C max. 0.1wt%/L) and, if appropriate, other auxiliaries.

16. A method for protecting plants against pests, which comprises applying an aqueous dispersion of granules as claimed in any one of claims 1 to 14 to the plants. Dated 11 May 2000 COGNIS DEUTSCHLAND GMBH Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON **o oeeoQ oo• o o- I ~o C08238