MESO-SIZED CAPSULES USEFUL FOR THE DELIVERY OF AGRICULTURAL CHEMICALS

• US 20110045975A1
• Filed: 08/05/2010
• Published: 02/24/2011
• Est. Priority Date: 08/07/2009
• Status: Active Grant

• Current Assignee: Corteva Agriscience LLC (Corteva, Inc.)
• Original Assignee: Dow Agrosciences LLC (Corteva, Inc.)
• Inventors: Zhang, Qiang, Liu, Lei, Kalantar, Thomas H., Ehr, Robert J., Yau, Kerrm Y., Zhao, Min, Schmidt, Dale C., Tolley, Mike P.
• Granted Patent: US 9,034,353 B2
• Time in Patent Office: Days
• US Class Current: 504/105
• CPC Class Codes: A01N 2300/00 Combinations or mixtures of active ingredients covered by classes A01N27/00 - A01N65/48 with other active or formulation relevant ingredients, e.g. specific carrier materials or surfactants, covered by classes A01N25/00 - A01N65/48
• CPC Class Codes: A01N 25/28 Microcapsules or nanocapsules
• CPC Class Codes: A01N 43/22 rings with more than six members
• CPC Class Codes: A01N 43/40 six-membered rings
• CPC Class Codes: A01N 43/653 1,2,4-Triazoles; Hydrogenated 1,2,4-triazoles
• CPC Class Codes: A01N 43/70 Diamino—1,3,5—triazines with only one oxygen, sulfur or halogen atom or only one cyano, thiocyano (—SCN), cyanato (—OCN) or azido (—N3) group directly attached to a ring carbon atom
• CPC Class Codes: A01N 47/38 containing the group >N—CO—N< where at least one nitrogen atom is part of a heterocyclic ring; Thio analogues thereof

Abstract

Various aspects disclosed herein disclose mesocapsules that include active ingredients such as agriculturally active ingredients including various fungicides, insecticides, miticides, herbicides, safeners and modifiers of plant physiology or structure. These mesocapsules are comprised of a polyurea shell and include hydrophilic groups on their surfaces. These mesocapsules have a volume-average diameter of about 500 nm or less and some of them have a volume-average diameter on the order of about 300 nm or less. These mesocapsules are especially well suited for delivering active ingredients that are not very soluble in water, many of these compounds have solubility values in the range of 1,000 ppm or less. Methods for making these mesocapsules include interfacial polycondensation reactions carried out in the presence of surfactants such as sodium dodecyl sulfate and another method in which all or most of the surfactant is replaced by adding amino acids to the aqueous phase of the interfacial reaction mixture before forming the final emulsion.

Claims

1. A composition for the delivery of an agricultural active ingredient, comprising:

a mesocapsule, the mesocapsule having a polymer shell; and

a poorly water soluble agricultural active ingredient, wherein the active ingredient is at least partially included within the polymer shell, the mesocapsule having a volume-average particle diameter between about 30 nm and about 500 nm.

2. The composition according to claim 1, wherein the polymer shell is comprised of at least one of a polyurea, a melamine-formaldehyde condensate, a urea-formaldehyde condensate, aminoplasts, a polyurethane, a polyamide, a polyolefin, a polysaccaharide, a protein, a silicone, a lipid, a modified cellulose, a gum, a polyacrylate, a polyphosphate, a polystyrene and a polyester.

3. The composition according to claim 2, wherein the polymer shell is comprised of polyurea.

4. The composition according to claim 3, wherein the polyurea is a reaction product of at least one polyisocyanate and at least one polyamine.

5. The composition according to claim 1, wherein the mesocapsule has a volume average diameter in the range of about 50 nm to about 300 nm.

6. The composition according to claim 1, wherein the shell includes hydrophilic functional groups and at least some of the hydrophilic functional groups contact water.

7. The composition according to claim 6, wherein the hydrophilic functional group on the surface of the shell is a carboxylate.

8. The composition according to claim 1 wherein the active ingredient has solubility in water of about 1,000 parts per million or less.

9. A method of controlling insects, mites, plant diseases or weeds including the steps of:

providing a formulation including the composition of claim 1, and

applying an agriculturally effective amount of the formulation to at least one of the following;

the plant, plant foliage, blossoms, stems, fruits, the area adjacent to the plant, soil, seeds, germinating seeds, roots, liquid and solid growth media, hydroponic growth solutions, treated surfaces, and into and onto the pest itself.

10. A method of controlling insects, plants diseases or weeds including the steps of:

providing a formulation including the composition of claim 1, and

applying an agriculturally effective amount of the formulation in mixture with one or more conventional formulations of agricultural active ingredients or nutrients to at least one of the following;

the plant, plant foliage, blossoms, stems, fruits, the area adjacent to the plant, soil, seeds, germinating seeds, roots, liquid and solid growth media, hydroponic growth solutions, treated surfaces, and into and onto the pest itself.

11. A method for synthesizing a mesocapsule, comprising the steps of:

providing an oil phase, the oil phase including at least one agricultural active ingredient and one or more polymer precursers capable of reacting to form a shell;

supplying an aqueous phase, the aqueous phase including water and at least one crosslinker;

adding a surfactant to at least one of the aqueous phase and the oil phase;

mixing the oil and the aqueous phases under shear conditions sufficient to form an emulsion having meso-sized droplets with a volume-average diameter of about 500 nm or less; and

reacting the polymer precurser with the crosslinker to form the mesocapsule.

12. The method according to claim 11, wherein the polymer precursers include polyisocyanate, siloxanes and other silicon-containing precursors.

13. The method according to claim 11 wherein the crosslinker is selected from the group consisting of water, amino acids, resorcinol, melamine, formaldehyde, urea, guanidine, guanidine compounds, diamines, polyamines, polyamidines and mixtures thereof.

14. The method according to claim 11, wherein the polymer prescursers include at least one polyisocyanate.

15. The method according to claim 14 wherein the at least one polyisocyanate is a mixture of PAPI™

27 and isophorone diisocyanate.

16. A method according to claim 11, wherein the surfactant is sodium dodecyl sulfate.

17. The method according to claim 11, wherein sufficient shear to form the emulsion is accomplished by either ultrasonication or high-pressure homogenization.

18. The method according to claim 13, wherein the crosslinker is selected from the group consisting of water, ethylenediamine, diethylenetriamine, triethylenetetramine and L-lysine.

19. The method according to claim 11, wherein the oil phase further includes between about 1 wt. % to about 90 wt. % of a solvent that substantially dissolves the agriculturally active ingredient.

20. The method according to claim 19, wherein the solvent is benzyl acetate, cyclohexanone, aromatic solvents, acetophenone, seed oils, esters of seed oils, paraffinic oils, and mixtures thereof.

21. The method according to claim 11, wherein the oil phase further includes between about 0.5 wt. % to about 10 wt. % of an ultrahydrophobe.

22. The method according to claim 21, wherein the ultrahydraphobe is hexadecane or Indopol™

H15.

23. The method according to claim 11, wherein the agricultural active ingredient is selected from the group consisting of fungicides, insecticides, miticides, herbicides, safeners and modifiers of plant physiology or structure.

24. The method of claim 11 wherein the oil phase of the mesocapsule is comprised of from about 1 to about 90 weight percent of AI.

25. A method for synthesizing a surfactant free mesocapsule, comprising the steps of:

providing an oil phase, the oil phase including at least one agricultural active ingredient and at least one polyisocyanate;

supplying an aqueous phase, wherein the aqueous phase includes at least one component wherein the component includes at least one functional moiety that is either a primary or secondary amine or a primary or secondary amino group and additionally at least one hydrophilic functional group;

mixing the oil and the aqueous phases to form an emulsion; and

reacting polyisocyanate with a crosslinker to form the mesocapsule.

26. The method according to claim 25, wherein the hydrophilic functional group is a carboxylate.

27. The method according to claim 25 wherein primary or secondary amine is an amino acid.

28. The method according to claim 27, wherein the amino acid is selected from the group consisting of lysine and glycine.