Pyroxasulfone Microcapsule Composition for Crop Injury Reduction
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Solution Overview
Problem
Conventional microencapsulation techniques for agrochemical active components are ineffective in dry fields due to elution issues and cause crop injury to useful plants, limiting their application and requiring a method to reduce or prevent such injury.
Innovation Solution
A microcapsule composition containing pyroxasulfone and a polyester block copolymer encapsulated in a polyurea or polyurethane membrane, with specific formulation and processing steps to ensure the pyroxasulfone crystal particles are not exposed on the surface and have a controlled release, reducing crop injury and enabling use in dry fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional microencapsulation techniques are used for pyroxasulfone, then the herbicide can be applied in paddy fields, but elution occurs through water and crop injury still happens
Solution Approach 1:
The patent changes the chemical composition parameters of the microcapsule wall material by using specific ratios of polyurea (formed from diisocyanate and water) and polyurethane (formed from diisocyanate and polyester block copolymer). This compositional parameter change creates a membrane that controls pyroxasulfone release differently from conventional microcapsules, reducing crop injury while maintaining herbicidal efficacy.
Solution Approach 2:
The patent employs a composite wall material consisting of polyurea and polyurethane in a specific ratio range (polyurea:polyurethane = 4:6 to 6:4). This composite structure combines the properties of both materials to achieve controlled release of pyroxasulfone, preventing both excessive elution in water and crop injury, thus resolving the contradiction between reliability and harmful effects.
2Adaptability or versatility
If pyroxasulfone is applied in dry fields, then broader application scope is achieved, but crop injury increases due to lack of water for elution control
Solution Approach 1:
The patent modifies the release mechanism parameters by changing from water-dependent elution to controlled diffusion through the polyurea-polyurethane membrane. This parameter change allows pyroxasulfone to be released in a controlled manner regardless of water availability, enabling safe application in both paddy fields and dry fields, thus expanding adaptability while preventing crop injury.
3Object-affected harmful factors
If microencapsulation is used to reduce crop injury, then useful plant safety improves, but application is limited to environments with plenty of water
Solution Approach 1:
The patent introduces the polyurea-polyurethane membrane as an intermediary layer between pyroxasulfone and the external environment. This membrane mediates the release of pyroxasulfone through controlled diffusion, replacing the water-dependent elution mechanism. As a result, the microcapsules can now function in both water-rich and water-poor environments while maintaining crop injury reduction, thus resolving the contradiction between safety and environmental adaptability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The microcapsule composition effectively reduces or prevents crop injury from pyroxasulfone, allowing its use in dry fields while maintaining herbicidal efficacy, as demonstrated by reduced plant height inhibition and herbicidal effect in soybean and cotton tests.
Implementation Method 1
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
Implementation Method 2
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
Implementation Method 3
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
Implementation Method 4
isocyanate reacting with water and water-soluble active hydrogen-containing compound in the aqueous phase to form a membrane made of polyurea or polyurethane
Data Source
AI summary
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.