Microcapsules encapsulating lambda-cyhalothrin
A composition comprising a microcapsule having a polyurea wall encapsulating a pyrethroid insecticide, wherein the polyurea wall of the microcapsule is made of polyurea polymers derived from a mixture of aromatic polyisocyanate (A) and aromatic diisocyanate (B), the weight ratio of (A) to (B) is 1:1, the polymer (or wall) content of each microcapsule is from 6 to 9% by weight, and the amount of the pyrethroid insecticide is from 15 to 60% by weight, each based on the weight of the microcapsule; such a composition providing improved worker exposure characteristics.
1 . A composition comprising a microcapsule having a polyurea wall encapsulating lambda cyhalothrin and dispersed titanium dioxide particles, wherein the polyurea wall of the microcapsule is made of polyurea polymers derived from a mixture of aromatic polyisocyanate (A) and aromatic diisocyanate (B), provided that the d50 median particle size diameter of the titanium dioxide particles is from 0.15 to 0.5 microns, the d50 median diameter of the microcapsule in the composition is from 1 to 4, microns, the weight ratio of (A) to (B) is about 1:1, the polymer (or wall) content of each microcapsule is from 7 to 8% by weight, the amount of titanium dioxide is present in an amount of from 3.5 to 6% by weight and the amount of lambda cyhalothrin is from 40 to 50% by weight, each based on the weight of the microcapsule; and the amount of the microcapsule in the composition is from 47 to 53% by weight, based on the weight of the composition.
2 . The composition according to claim 1 , in which the aromatic polyisocyanate is polymethylene polyphenylisocyanate.
3 . The composition according to claim 2 , in which the aromatic diisocyanate is toluene diisocyanate.
4 . The composition according to claim 3 , in which the toluene diisocyanate is an isomeric mixture of toluene diisocyanate.
5 . The composition according to claim 1 , wherein the weight ratio of (A) to (B) is 1:1.
6 . The composition according to claim 1 , further comprising thiamethoxam wherein the thiamethoxam is not encapsulated.
7 . The composition according to claim 6 , further comprising lufenuron wherein the lufenuron is not encapsulated.
8 . A composition having an organic phase and an aqueous phase, comprising:
a polyurea polymer microcapsule encapsulating lambda-cyhalothrin;
wherein the lambda-cyhalothrin is about 22.8% w/w;
wherein the polyurea polymer of the microcapsule is about 3.8% w/w formed from isocyanate monomers, wherein the isocyanate monomers are a mixture of aromatic polyisocyanate (A) and aromatic diisocyanate (B) and the weight ratio of (A) to (B) is about 1:1;
wherein the d50 diameter of the microcapsules is about 1.5-3.5 microns;
wherein the organic phase of the composition is about 49.7% w/w; and
wherein the aqueous phase of the composition is about 50.3% w/w.
9 . The composition according to claim 8 , in which the aromatic polyisocyanate is polymethylene polyphenylisocyanate.
10 . The composition according to claim 9 , in which the aromatic diisocyanate is toluene diisocyanate.
11 . The composition according to claim 10 , in which the toluene diisocyanate is an isomeric mixture of toluene diisocyanate.
12 . The composition according to claim 8 , wherein the weight ratio of (A) to (B) is 1:1.
13 . A composition prepared by the steps, comprising: combining the composition of claim 8 with thiamethoxam, wherein the thiamethoxam is present in the composition at about 12.6% w/w of the composition.
14 . A composition prepared by the steps, comprising: combining the composition of claim 8 with thiamethoxam and lufenuron, wherein the thiamethoxam is present in the composition at about 13.2% w/w of the composition and the lufenuron is present in the composition at about 6.6% w/w of the composition.