Microcapsule composition, method for manufacturing same, agrochemical formulation comprising same and weed control method
The present invention aims to provide a microcapsule composition that enables reduction or prevention of injury of useful plants caused by pyroxasulfone, a production method therefor, an agrochemical formulation containing the same, and a weed control method. A microcapsule composition including pyroxasulfone and a polyester block copolymer encapsulated therein, an agrochemical formulation containing the same, and a weed control method are provided. A method of producing the microcapsule composition, the method including: an emulsifying dispersion step of performing high-speed stirring of pyroxasulfone crystal particles, a polyester block copolymer, isocyanate, oily phase, and aqueous phase at a peripheral speed of 10,000 to 50,000 mm/s to allow emulsifying dispersion of the oily phase in the aqueous phase, to form emulsion particles of the oily phase; and a membrane formation step of forming a membrane on at least the surface of the emulsion particles of the oily phase formed by the emulsifying dispersion step; is also provided.
1 . A microcapsule composition comprising pyroxasulfone and a polyester block copolymer encapsulated therein,
wherein the polyester block copolymer has CAS Registry No. 2142005-01-2, a brown powder appearance, a melting temperature of 85° C., oil compatibility with vegetable oil and paraffinic oil, and oil incompatibility with methylated seed oil, and
wherein the microcapsule composition is obtained by stirring pyroxasulfone crystal particles, an oily phase, the polyester block copolymer, isocyanate and an aqueous phase, the oily phase is an aromatic hydrocarbon selected from the group consisting of benzene, toluene, xylene, solvent naphtha, alkylnaphthalene and phenylxylylethane, and a mixture of the oily phase and the polyester block copolymer has a viscosity of 10 to 52 mPa's at 20° C.
2 . The microcapsule composition according to claim 1 , wherein the pyroxasulfone and the polyester block copolymer are encapsulated in a membrane made of polyurea and/or polyurethane.
3 . The microcapsule composition according to claim 2 , wherein isocyanate forming the polyurea and/or polyurethane is aromatic isocyanate.
4 . The microcapsule composition according to claim 1 , wherein the pyroxasulfone comprises crystal particles that are not exposed on a surface of the microcapsule composition.
5 . The microcapsule composition according to claim 1 , having a volume average diameter of 5 to 100 μm.
6 . The microcapsule composition according to claim 1 , wherein the pyroxasulfone crystal particles have a volume average diameter of 2 to 50 μm.
7 . The microcapsule composition according to claim 1 , which is obtained by stirring the mixture of the oily phase and the polyester block copolymer with the pyroxasulfone crystal particles, the isocyanate, and the aqueous phase.
8 . The microcapsule composition according to claim 1 , wherein the aqueous phase further comprises a water-soluble active hydrogen-containing compound.
9 . The microcapsule composition according to claim 8 , wherein the water-soluble active hydrogen-containing compound is at least one compound selected from the group consisting of a polyol and a polyamine.
10 . The microcapsule composition according to claim 1 , wherein the aqueous phase further comprises an emulsifier.
11 . The microcapsule composition according to claim 10 , wherein the emulsifier is polyvinyl alcohol.
12 . The microcapsule composition according to claim 8 , wherein the total amount of the isocyanate and the water-soluble active hydrogen-containing compound is 1 to 10 parts by mass with respect to 1 part by mass of the pyroxasulfone crystal particles.
13 . The microcapsule composition according to claim 1 , wherein the stirring is carried out at a peripheral speed of 10,000 to 50,000 mm/s.
14 . The microcapsule composition according to claim 1 , for soil treatment or foliage treatment.
15 . An agrochemical formulation comprising the microcapsule composition according to claim 1 .
16 . The agrochemical formulation according to claim 15 , which is a powder, granule, wettable powder, wettable granule, aqueous suspension, or oily suspension.
17 . The agrochemical formulation according to claim 15 , containing no crop injury-reducing agent.
18 . A method of producing a microcapsule composition comprising pyroxasulfone and a polyester block copolymer encapsulated therein, wherein the polyester block copolymer has CAS Registry No. 2142005-01-2, a brown powder appearance, a melting temperature of 85° C., oil compatibility with vegetable oil and paraffinic oil, and oil incompatibility with methylated seed oil,
the method comprising:
an emulsifying dispersion step of performing high-speed stirring of pyroxasulfone crystal particles, the polyester block copolymer, isocyanate, an oily phase, and an aqueous phase at a peripheral speed of 10,000 to 50,000 mm/s to allow emulsifying dispersion of the oily phase in the aqueous phase, to form emulsion particles of the oily phase, wherein the oily phase is an aromatic hydrocarbon selected from the group consisting of benzene, toluene, xylene, solvent naphtha, alkylnaphthalene and phenylxylylethane and the oily phase formed in the emulsifying dispersion step has a viscosity of 10 to 52 mPa's at 20° C.; and
a membrane formation step of forming a membrane on at least a surface of the emulsion particles of the oily phase formed by the emulsifying dispersion step.
19 . The method of producing the microcapsule composition according to claim 18 , comprising a step of mixing the polyester block copolymer with the oily phase before the emulsifying dispersion step.
20 . The method of producing the microcapsule composition according to claim 18 , wherein, in the membrane formation step, the isocyanate is reacted with at least one of water and the water-soluble active hydrogen-containing compound in the aqueous phase, to form a membrane made of polyurethane or polyurea on at least the surface of the emulsion particles of the oily phase formed by the emulsifying dispersion step.
21 . The method of producing the microcapsule composition according to claim 18 , wherein the microcapsule composition has a volume average diameter of 5 to 100 μm.
22 . The method of producing the microcapsule composition according to claim 18 , wherein the pyroxasulfone crystal particles have a volume average diameter of 2 to 50 μm.
23 . A method of controlling weeds, comprising performing a treatment with the microcapsule composition according to claim 1 , or with an agrochemical formulation comprising the microcapsule composition according to claim 1 , in agricultural land for growing a useful plant.
24 . The method according to claim 23 , wherein the useful plant is soybean or cotton.
25 . The method according to claim 23 , wherein the agricultural land is a dry field.
26 . The method according to claim 23 , wherein the treatment is a soil treatment or a foliage treatment.