Polyurea Microcapsule Formulations for Prolonged Insecticidal Activity
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Solution Overview
Problem
Current insecticidal formulations, particularly microcapsules, fail to provide prolonged residual activity beyond three months and often suffer from stability issues and toxicity concerns, lacking high knockdown and insecticidal efficacy after six and nine months, as well as operator safety concerns.
Innovation Solution
Formulations of microcapsules with polyurea walls obtained by interfacial polymerization of diphenylmethylen-4,4′-diisocyanate (MDI) and polymethylenepolyphenylisocyanate (PAPI), containing active principles from pyrethroid and/or neonicotinoid classes, with synergizing agents like piperonyl butoxide, offering prolonged knockdown and insecticidal activity exceeding three months, and maintaining stability for at least two years.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If microcapsule formulations with polyurea walls are used to extend residual activity, then duration of action increases beyond three months, but stability and toxicity control become more challenging
Solution Approach 1:
The patent modifies the polyurea wall composition parameters by incorporating specific ratios of polymethylene-polyphenylisocyanate (PMPPI) and toluene diisocyanate (TDI), adjusting crosslinking density and hydrophobicity to achieve optimal balance between prolonged activity (9+ months) and formulation stability. This parameter optimization allows the microcapsules to maintain controlled release properties while ensuring long-term storage stability.
Solution Approach 2:
The patent employs composite microcapsule structures combining polyurea wall material with encapsulated pyrethroid and/or neonicotinoid active principles. This composite approach enables the shell to provide structural integrity and controlled release while the core maintains high insecticidal potency, achieving both extended duration and reliability simultaneously.
2Duration of action of stationary object
If microcapsules with highly crosslinked polyurea walls are used to reduce permeability, then residual activity is prolonged, but manufacturing complexity increases
Solution Approach 1:
The patent replaces complex mechanical crosslinking methods with chemical crosslinking through isocyanate-amine reactions during interfacial polymerization. This substitution simplifies the manufacturing process by achieving high crosslinking density through controlled chemical reactions rather than complex mechanical processing, reducing manufacturing complexity while maintaining capsule integrity.
3Object-affected harmful factors
If conventional insecticidal products are applied for preventive action, then immediate protection is achieved, but inhalation toxicity and skin irritation occur
Solution Approach 1:
The patent uses thin polyurea microcapsule shells (average wall thickness 0.5-2 μm) that provide controlled release barriers. These flexible thin film structures allow gradual diffusion of active principles while preventing direct contact between insects and bulk insecticide, eliminating inhalation and skin toxicity risks while maintaining protective efficacy.
Solution Approach 2:
The polyurea microcapsule wall acts as an intermediary between the active insecticidal principles and the environment. It mediates controlled release of pyrethroids and neonicotinoids, providing protection while eliminating direct exposure hazards of conventional insecticide formulations.
4Power
If microcapsule formulations are designed for high knockdown effect, then insecticidal activity increases, but residual activity duration decreases
Solution Approach 1:
The patent implements periodic release of active principles through the polyurea microcapsule matrix. The crosslinked structure provides initial rapid release for knockdown effect, followed by sustained periodic diffusion that maintains residual activity for 9+ months. This temporal release pattern reconciles high power with extended duration.
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 described microcapsule formulations demonstrate extended insecticidal activity and knockdown effects for over six and nine months, combined with high stability and reduced toxicity, making them suitable for professional and domestic applications, including areas like stables and industrial spaces.
Implementation Method 1
microcapsules with polyurea walls obtainable by interfacial polymerization of diphenylmethylen-4,4'-diisocyanate (MDI), optionally in admixture with polymethylenepolyphenylisocyanate (PAPI)
Data Source
AI summary
Use of formulations comprising polyurea microcapsules obtainable by interfacial polymerization of diphenylmethylen-4,4′-diisocyanate (MDI), optionally in admixture with polymethylenepolyphenylisocyanate (PAPI), said formulations having a prolonged knockdown and killing effect longer than at least 3 months, preferably at least of 6 months, still more preferably at least of 9 months from the application, wherein the microcapsules comprise:an active principle selected from the pyrethroid and/or neonicotinoid classes,synergizing agents selected between PEO and Verbutin,the concentration of the active principle in the microcapsule as % by weight on the total of the microcapsule is comprised between 1 to and 60%the average diameter of the microcapsules is comprised between 2 and 50 μm.