Agrochemical Microcapsule Formulation for Stability and Efficacy

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Solution Overview

Problem

Existing microcapsule formulations with polyurea shells and water-immiscible pesticides face issues such as high crystallization tendency, low stability across temperature ranges, and either knock-down or residual efficacy, rather than balanced performance.

Innovation Solution

Microcapsules with a polyurea shell and a core containing a pesticide, a water-immiscible solvent A, and at least 5 wt % of an aprotic, polar solvent B with solubility in water from 0.5 to 20 g/l, specifically using solvents like 2-heptanone, which improves stability and efficacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If water-immiscible solvents are used to dissolve pesticides in microcapsules, then the pesticide can be effectively encapsulated, but the formulation shows high crystallization tendency and low stability across temperature ranges

Engineering Contradiction:
Improveformulation stabilityVSAvoidcrystallization tendency
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameters of the solvent system by introducing aprotic polar solvents (acetonitrile, dimethyl carbonate, ethyl methyl carbonate) with specific solubility characteristics (0.5-20 g/l in water). This parameter change modifies the solvent's interaction with the pesticide, preventing crystallization while maintaining encapsulation effectiveness and improving temperature stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite solvent system combining water-immiscible properties with aprotic polar characteristics. This composite approach integrates the benefits of both solvent types: the water-immiscibility provides effective encapsulation while the aprotic polar nature reduces crystallization tendency and enhances formulation stability across temperature ranges.

Inventive Principle:
Principle #40Composite materials

2Duration of action of moving object

If conventional pesticides are applied, then immediate knock-down effect is achieved, but residual efficacy is insufficient

Engineering Contradiction:
Improveresidual efficacyVSAvoidknock-down effect
Core Design Contradiction:
Duration of action of moving objectVSSpeed

Solution Approach 1:

The microcapsule formulation provides dynamic release of the pesticide, transitioning from immediate release (knock-down effect) to sustained release (residual efficacy). The capsule structure allows the pesticide to be released gradually over time, maintaining effective concentrations in the environment and on plant surfaces, thus achieving both immediate and long-term control.

Inventive Principle:
Principle #15Dynamics

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 formulation reduces crystallization, enhances stability across temperatures, achieves both knock-down and residual efficacy, improves compatibility with other pesticides, and provides effective protection from UV-light, with reduced wind drift and toxicological impact.

Implementation Method 1

a core, which contains a pesticide, a water-immiscible solvent A and at least 5 wt % of an aprotic, polar solvent B, which has a solubility in water from 0.5 to 20 g/l at 20° C.

Methodology Applied
Scientific EffectSolubility: Solvation

Implementation Method 2

Microcapsules comprising a polyurea shell and a core

Methodology Applied
Scientific EffectEncapsulation: Physical Containment

Data Source

PatentUS9241912B2Agrochemical formulation comprising encapsulated pesticide
Publication Date: 2016.01.26 BASF SE

AI summary

The present invention relates to microcapsules comprising a polyurea shell and a core, which contains a pesticide, a water-immiscible solvent A and at least 5 wt % of an aprotic, polar solvent B, which has a solubility in water from 0.5 to 20 g/l at 20° C., based on the total weight of the solvents in the core. It further relates to microcapsules comprising a shell and a core, which contains a pesticide and 2-heptanone; to a method for preparing said microcapsules; to an aqueous composition comprising said microcapsules; and to a method for controlling phytopathogenic fungi and/or undesired plant growth and/or undesired attack by insects or mites and/or for regulating the growth of plants, with said microcapsules.