Safe delivery system for agriculturally active material
A safe delivery system of agriculturally active material is formed using an encapsulation process. A microencapsulated suspension of agriculturally active material includes an encapsulating agent formed from a graft copolymer of starch and at least one vinyl monomer.
1. An encapsulation process for preparing a microencapsulated suspension for a safe delivery system of an agriculturally active material, comprising the steps of:
a) preparing an organic phase comprising an agriculturally active water immiscible material and a solvent, in the presence of at least one surfactant;
b) preparing an aqueous phase comprising water, a starch, and a protective colloid;
c) heating the aqueous phase to obtain a gelatinized aqueous phase followed by cooling;
d) adding the organic phase of step (a) into the gelatinized aqueous phase of step (c) to form an oil-in-water emulsion;
e) adding an initiator to the oil-in-water emulsion of step (d) in an inert atmosphere;
f) adding a vinyl monomer for graft reaction to occur and resulting in obtaining a microencapsulated suspension;
g) neutralizing the microencapsulated suspension of step (f) followed by adding a structuring agent.
2. The encapsulation process of claim 1 , wherein the vinyl monomer is vinyl acetate.
3. The encapsulation process of claim 1 , wherein the starch and the vinyl monomer are present in a ratio of 1:1 to 1:5.
4. The encapsulation process of claim 3 , wherein the starch and the vinyl monomer are present in a ratio is 1:1 to 1:2.
5. The encapsulation process of claim 1 , wherein said initiator is a free radical initiator.
6. The encapsulation process of claim 1 , wherein said initiator is ceric ammonium nitrate.
7. The encapsulation process of claim 1 , wherein said surfactant is an anionic surfactant or non-ionic surfactant or a combination thereof.
8. The encapsulation process of claim 1 , wherein said step of preparing an aqueous phase further comprises a biocide.
9. The encapsulation process of claim 8 , wherein said biocide is selected from the group consisting of methyl paraben, ethyl paraben and butyl paraben.
10. The encapsulation process of claim 1 , wherein said protective colloid is an alkyl metal or an alkaline earth metals of alkyl naphthalene sulphonate.
11. The encapsulation process of claim 1 , wherein said agriculturally active water immiscible material is a pyrethroid.
12. The encapsulation process of claim 11 , wherein said agriculturally active water immiscible material is Lambda Cyhalothrin.
13. The encapsulation process of claim 1 , wherein said step of preparing an aqueous phase further comprises a second surfactant.
14. The encapsulation process of claim 1 , wherein said step of preparing an aqueous phase further comprises an anti-freezing agent.
15. The encapsulation process of claim 1 , wherein said step of heating said aqueous phase includes heating at a temperature of 65–85° C.
16. The encapsulation process of claim 1 , wherein said oil-in-water emulsion includes oil droplets having an oil droplet size of less than 5 microns.
17. The encapsulation process of claim 1 , wherein said step of adding an initiator to the oil-in-water emulsion includes maintaining a pH between 2–5.
18. The encapsulation process of claim 1 , wherein said step of adding an initiator to the oil-in-water emulsion includes maintaining a temperature ranging between 15–30° C.
19. The encapsulation process of claim 1 , wherein said step of adding vinyl monomer includes maintaining a temperature of 15–30° C.
20. The encapsulation process of claim 1 , wherein said step of neutralizing the microencapsulated suspension includes neutralizing with an organic aliphatic amine.
21. The encapsulation process of claim 1 , wherein said step of preparing an organic phase includes continuously stirring to get a clear solution.
22. The encapsulation process of claim 1 , wherein said step of heating the aqueous phase is followed by cooling to a temperature of 20–45° C.
23. The encapsulation process of claim 1 , wherein said step of adding the organic phase of step (a) into the gelatinized aqueous phase of step (c) includes adding slowly with a high shear.
24. The encapsulation process of claim 1 , wherein said inert atmosphere is an oxygen-free inert atmosphere.
25. A microcapsule for the safe delivery of an agriculturally active material comprising,
a) an inner core including an agriculturally active material;
b) an outer shell including a graft copolymer comprising a starch and at least one vinyl monomer.
26. The microcapsule of claim 25 , wherein said agriculturally active material is a pyrethroid.
27. The microcapsule of claim 26 , wherein said agriculturally active material is Lambda Cyhalothrin.
28. The microcapsule of claim 27 , wherein said vinyl monomer is vinyl acetate monomer.
29. The microcapsule of claim 25 , wherein the starch and the vinyl monomer are present in a ration of 1:1 to 1:5.
30. The microcapsules of claim 25 , wherein said microcapsules have a size of less than 5 microns.