1. A process of preparing a stable aqueous nano urea formulation, the process
comprising:
a. preparing 0.5 to 1.25% (w/v) of a chitosan solution in 5 to 10% (v/v)
5 acetic acid;
b. adding 0.1 to 0.5% (v/v) of ammonium hydroxide to the chitosan
solution to obtain a first mixture;
c. adding 1 to 11% (v/v) glacial acetic acid to the first mixture to obtain
a second mixture;
10 d. mixing an aqueous urea comprising urea in a weight range of 25 to
45% (w/v), with the second mixture, followed by addition of a
crosslinking agent and optionally adding a spreading agent to obtain
the stable aqueous nano urea formulation.
2. The process as claimed in claim 1, wherein the formulation comprises
15 chitosan in a range of 0.1 to 0.6% (w/v).
3. The process as claimed in claim 1, wherein 0.5 to 10% (w/v) of the
crosslinking agent is added.
4. The process as claimed in claim 1, wherein the crosslinking agent is selected
from sodium tripolyphosphate (STPP), polyacrylic acid, copolymers of
20 acrylic acid, or combinations thereof.
5. The process as claimed in claim 1, wherein the spreading agent is selected
from trisiloxane ethoxylate, or other acrylic based polymeric surfactants in an
amount of 0.05 to 2% (v/v) with respect to the formulation.
6. The process as claimed in claim 1, wherein mixing the aqueous urea with the
25 second mixture is carried out by drop-wise addition or through a spray nozzle.
7. The process as claimed in claim 1, wherein the formulation has pH in a range
of 4.4 to 6.5.
8. A stable aqueous nano urea formulation comprising:
a. 1% to 45% (w/v) of urea;
30 b. 0.1% to 0.6% (w/v) of chitosan;
c. 5% to 15% (v/v) of acetic acid;
23
d. 0.02% to 0.2 % (v/v) of sodium tripolyphosphate;
e. 0.1% to 0.5% (v/v) of ammonium hydroxide; and
f. 0.1% to 2.0% (v/v) of spreading agent.
9. The formulation as claimed in claim 8, wherein the formulation is stable with
5 a shelf life of at least 2 years.
10. The formulation as claimed in claim 8, wherein the formulation has a particle
size in a range of 3 to 310 nm and a zeta potential in a range of 5 to 30 mV.