STABILIZATION OF SUSPENSION CONCENTRATES BY HYDROPHOBIC FUMED SILICA

Abstract

The invention relates to an aqueous agrochemical composition comprising a) suspended particles of an active ingredient; and b) hydrophobically modified fumed silica. It also relates to use of the hydrophobically modified fumed silica for stabilizing an aqueous agrochemical composition comprising suspended particles of an active ingredient; to a method of stabilizing an agrochemical composition comprising the suspended particles of an active ingredient; to a method for treating, controlling, preventing or protecting animals against infestation of infection by parasites by application of the agrochemical composition; to a method of preparing the agrochemical composition; and to plant propagation material containing the agrochemical composition.

Claims

1. An aqueous agrochemical composition comprising a) suspended particles of dimpropyridaz; and b) hydrophobically modified fumed silica.

2. The agrochemical composition of claim 1, containing dimpropyridaz at a concentration of at least 10 wt % based on the total weight of the agrochemical composition.

3. The agrochemical composition of claim 1, containing the silica in a concentration of from 0.01 to 10 wt % based on the total weight of the agrochemical composition.

4. The agrochemical composition according to claim 1, containing the silica in a concentration of at least 0.1 wt % based on the total weight of the agrochemical composition.

5. The agrochemical composition according to claim 1 having a weight ratio of the dimpropyridaz to the silica from 500:1 to 5:1.

6. The agrochemical composition according to claim 1, wherein the silica has a BET-surface of from 10 to 500 m.sup.2/g according to DIN ISO 9277:2014-01.

7. The agrochemical composition according to claim 1, wherein the silica has a carbon content of at least 0.5 wt % based on the total weight of the hydrophobically modified silica.

8. The agrochemical composition according to claim 1, wherein the suspended particles of dimpropyridaz have a mean diameter of from 0.5 μm to 20 μm.

9. The agrochemical composition according to claim 1, wherein the hydrophobically fumed silica has at least one covalently attached hydrocarbon chain containing from 1 to 20 carbon atoms.

10. The agrochemical composition according to claim 1, containing a second active ingredient selected from insecticides, fungicides, and herbicides.

11. (canceled)

12. A method of stabilizing an aqueous agrochemical composition comprising suspended particles of dimpropyridaz comprising contacting a hydrophobically modified fumed silica with particles of dimpropyridaz and water.

13. A method for treating, controlling, preventing or protecting animals against infestation or infection by parasites by administering or applying orally, topically or parenterally to the animals the agrochemical composition as defined in claim 1.

14. A method of preparing the agrochemical composition according to claim 1 comprising contacting the hydrophobically modified fumed silica as with dimpropyridaz in the presence of water.

15. A plant propagation material containing the agrochemical composition as defined in claim 1.

Description

EXAMPLES

[1191] The following ingredients were used for preparing the agrochemical compositions of the examples.

[1192] Insecticide A: 1-[(1RS)-1,2-dimethylpropyl]-N-ethyl-5-methyl-N-pyridazin-4-yl-1H-pyrazole-4-carboxamide.

[1193] Dispersant: lignosulfonate, organic sulfur content approximately 9 wt %

[1194] Antifoam: emulsion of dimethylsiloxan on silica particles, defoamer content 20 wt %

[1195] Biocide A: glycol based solution of benzisothiazolinone

[1196] Biocide B: aqueous composition of benzisothiazolinones and 5-chloro-2-methylisothiazolin-3-one

[1197] Silica Particles A: hydrophilic fumed silica particles, BET surface 200 m.sup.2/g, mean particle diameter 12 nm.

[1198] Silica Particles B: hydrophilic fumed silica particles, BET surface 300 m.sup.2/g.

[1199] Silica Particles C: hydrophilic fumed silica particles, BET surface 50 m.sup.2/g.

[1200] Silica Particles D: hydrophobic fumed silica particles, BET surface 220-280 m.sup.2/g, surface modified with octamethylcyclotetrasiloxane, carbon content 1.5-3 wt %.

[1201] Silica Particles E: hydrophobic fumed silica particles, BET surface 125-175 m.sup.2/g, surface modified with octylsilyl groups, carbon content 4.5-6.5 wt %.

[1202] Silica Particles F: surface treated fumed silica particles, hydrophobic and hydrophilic properties, BET surface 190 m.sup.2/g, produced by surface modification of Silica Particles B with hexadecylsilane, carbon content 0.9-1.8 wt %.

[1203] Silica Particles G: hydrophobic fumed silica particles, surface modified with dimethyldichlorosilane, water-solubility below 0.1 g/l, BET surface 90-130 m.sup.2/g, carbon content 0.6 to 1.2 wt % Silica Particles H: hydrophobic fumed silica particles, BET surface 150-190 m.sup.2/g, surface modified with dimethyldichlorosilane, carbon content 0.8-1.4 wt %.

[1204] Wet A: ethoxylated castor oil, 40 polymerized ethylene oxide units per molecule on average, saponification value 58-66 (according to ISO 3657).

Example-1

[1205] Suspension concentrates SC-1 to SC-8, and control SC-C1 were prepared containing the ingredients according to Table A. The suspension concentrates differed by the type of Silica Particle used, as provided in Table B, wherein SC-C1 did was produced without any Silica Particles.

[1206] The suspension concentrates were prepared by adding in a first step Insecticide A, 50% of the total amount of the Wet A, Dispersing Agent, Antifoam, Biocide A, Biocide B, acetic acid, and, in case of SC-1 to SC-8, the Silica Particles to water.

[1207] The resulting mill base was homogenized in a second step until uniform, and then milled in a bead mill until a mean particle size of 2-3 microns was achieved. The resulting composition was mixed in a third step with xanthan gum, which had been hydrated as a 3 wt % dilution in water, and the remaining Wet A until homogenous.

[1208] The suspension concentrates were then placed in a 20° C./40° C. cycling chamber for one day or one month (24 hours at 20° C. and then 24 hours at 40° C.), upon which the suspension concentrates were analyzed by visual inspection and by testing the rheological properties. The results of these analyses were summarized in Table B.

TABLE-US-00001 TABLE A Ingredients of suspension concentrates SC-1 to SC-8 Component Concentration [wt %] Insecticide A 20.85 Wet A 8.00 Dispersant 2.00 Antifoam 0.40 Biocide A 0.20 Biocide B 0.10 Xanthan guml 0.13 Acetic acid 0.09 Silica Particles 1.00 Water to 100

TABLE-US-00002 TABLE B Silica Particles contained in suspension concentrates SC-1 to SC-8; and results of stability analysis after incubation in the cycling chamber. SC-C1 did not contain any Silica Particles, but bas balanced with water. Stability Analyses after incubation in the cycling chamber Suspension Incubation one Incubation one Concentrate Silica Particles day month SC-C1 Balanced by water Gelled Gelled SC-1 Silica Particles A Gelled Gelled SC-2 Silica Particles B Gelled Gelled SC-3 Silica Particles C Gelled Gelled SC-4 Silica Particles D Flowable Flowable SC-5 Silica Particles E Flowable Flowable SC-6 Silica Particles F Flowable Slightly Flowable SC-7 Silica Particles G Flowable Flowable SC-8 Silica Particles H Flowable Flowable

Example-2

[1209] Suspension concentrates SC-9 to SC-13, and SC-C2 were prepared containing the ingredients according to Table C. The suspension concentrates differed by the concentration of Silica Particles G, as provided in Table D.

[1210] The suspension concentrates were prepared by adding in a first step Insecticide A, 50% of the total amount of the Wet A, Dispersing Agent, Antifoam, Biocide A, Biocide B, acetic acid, and the allotted amount of the Silica Particles G to water.

[1211] The resulting mill base was homogenized in a second step until uniform, and then milled in a bead mill until a mean particle size of 2-3 microns was achieved. The resulting composition was mixed in a third step with xanthan gum, which had been hydrated as a 3 wt % dilution in water, and the remaining Wet A until homogenous.

[1212] The suspension concentrates were then placed in a 20° C./40° C. cycling chamber for two weeks (24 hours at 20° C. and then 24 hours at 40° C.), upon which the suspension concentrates were analyzed by visual inspection and by testing the rheological properties. The results of these analyses were summarized in Table D.

TABLE-US-00003 TABLE C Ingredients of suspension concentrates SC-9 to SC-14 Component Concentration [wt %] Insecticide A 31.82 Wet A 8.00 Dispersant 3.00 Antifoam 0.40 Biocide A 0.20 Biocide B 0.10 Xanthan guml 0.06 Acetic acid 0.15 Silica Particles G see Table D Water to 100

TABLE-US-00004 TABLE D Silica Particles contained in suspension concentrates SC-9 to SC-13; and results of stability analysis after incubation in the cycling chamber. SC-C2 did not contain any Silica Particles. Stability Analyses after Suspension Concentration of Silica incubation in Concentrate Particles G in wt % the cycling chamber SC-C2 0.0 Gelled SC-9 0.5 Flowable SC-10 1.0 Flowable SC-11 1.5 Flowable SC-12 2.0 Slightly Flowable SC-13 3.0 Slightly Flowable