Microcapsule Suspensions High AI Load Solvent Reduction
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Solution Overview
Problem
Existing microcapsule formulations for agriculturally active ingredients like trifluralin require high volumes of non-aqueous solvents due to the insolubility of these compounds in water, leading to increased costs and regulatory compliance issues related to volatile organic compounds, and result in lower AI load per microcapsule.
Innovation Solution
The development of microcapsules with a polymeric shell encapsulating both a lipophilic polymer and the agriculturally active ingredient trifluralin, using an oil-in-water emulsion process that reduces solvent volume through interfacial polycondensation reactions and mini-emulsion polymerization, allowing for higher AI content and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If large volumes of non-aqueous solvents are used to dissolve water-insoluble agriculturally active ingredients, then the AI can be effectively incorporated into microcapsules, but the cost of forming microcapsules increases and volatile organic compound emissions increase
Solution Approach 1:
The patent changes the physical state parameter of the agriculturally active ingredient from solid to liquid by heating above its melting point (trifluralin melting point is 60-65°C), enabling it to be dissolved in minimal lipophilic solvent and incorporated into microcapsules at high concentrations (40-70% AI content) without requiring large volumes of volatile organic solvents
Solution Approach 2:
The patent uses a polymeric shell (formed from polymers like polyacrylonitrile, polyacrylic acid, or polyvinyl alcohol) to encapsulate the AI and lipophilic polymer core, creating a stable microcapsule structure that protects the AI while enabling high loading concentrations without excessive solvent use
2Quantity of substance
If high levels of agriculturally active ingredient are incorporated into microcapsules, then storage, transport and application become easier, but the formulation becomes more difficult to manufacture due to AI insolubility in water
Solution Approach 1:
The patent introduces a lipophilic polymer (such as polyacrylate, polyethylene glycol, or carboxymethyl cellulose) as an intermediary substance that is soluble in both the lipophilic AI and the aqueous phase, facilitating the incorporation of high levels of water-insoluble AI into microcapsules through emulsion polymerization without compromising manufacturability
Solution Approach 2:
The patent replaces mechanical dissolution methods with chemical polymerization processes, using emulsion polymerization to form microcapsules that encapsulate the AI within a polymeric matrix, enabling high AI content (40-70%) to be achieved through chemical rather than mechanical means
3Ease of operation
If solid agriculturally active ingredients are used, then storage and handling are simplified, but they require dissolution in large volumes of non-aqueous solvents due to water insolubility
Solution Approach 1:
The patent changes the temperature parameter during processing to above the AI melting point (heating trifluralin to 70-80°C), transforming it from solid to liquid state temporarily for dissolution and encapsulation, then allowing it to crystallize within the microcapsule upon cooling, achieving high AI content with minimal solvent while maintaining handling simplicity
Solution Approach 2:
The patent creates a composite microcapsule structure consisting of a lipophilic polymer core containing the AI, encapsulated within a hydrophilic polymeric shell, forming a composite material that combines the advantages of solid AI handling with efficient encapsulation and minimal solvent requirements
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
This approach enables the formation of microcapsules with higher AI load and reduced solvent usage, enhancing stability and regulatory compliance by delaying AI crystallization and minimizing volatile organic solvent use, resulting in a more cost-effective and efficient delivery of agriculturally active compounds.
Implementation Method 1
forming a microcapsule suspension via an interfacial polycondensation reaction including the step of adding a water soluble shell forming material to the oil-in-water emulsion
Implementation Method 2
emulsifying said lipophilic phase in the presence of water to form an oil-in-water emulsion
Implementation Method 3
polymerizing the lipophilic polymer selected from the group consisting of polymeric acrylates
Data Source
AI summary
Materials and methods for the formation of microcapsules that include a high concentration of agriculturally active ingredients (AIs) and a lipophilic polymer encapsulated within a polymeric shell formed via an interfacial polycondensation reaction. Under some conditions, these microcapsules may be formed using less lipophilic solvent than is required using convention microencapsulation techniques. These inventive methods include forming an oil-in-water emulsion in some cases using a first polymer as a lipophilic solvent for the AI and forming a microcapsule that includes the AI and polymer. Other methods include forming a microcapsule that includes a lipophilic monomer, agriculturally active ingredient and initiator having a polymeric shell then elevating the temperature to initiate polymerization of the monomer with the microcapsule.