Microcapsule Release Rate Modulation via Solvent Ratio Adjustment
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Solution Overview
Problem
Current microencapsulation methods for agropharmaceutical active ingredients lack the ability to modulate the release rate of active ingredients once the microcapsules are formed, making it difficult to adjust the release profile based on specific agricultural applications, such as pre-seed or post-emergency treatments.
Innovation Solution
A method involving the preparation of an aqueous suspension of microcapsules and a water-emulsifiable liquid containing a solvent and surfactants, where the ratio of solvent to active ingredient is adjusted to control the release rate by mixing these components with water, allowing for the modulation of the release profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the shell thickness is increased to slow the release of active ingredient, then the release rate is reduced, but the biological efficacy becomes negligible
Solution Approach 1:
The invention applies dynamics by making the capsule shell permeability adjustable rather than fixed. The shell's permeability can be dynamically modified by external stimuli such as temperature changes or chemical agents, allowing the release rate to be tuned between slow and fast modes. This enables the system to adapt the release characteristics to match different application requirements, resolving the contradiction between slow release and biological efficacy.
Solution Approach 2:
The invention utilizes parameter changes by modifying the physical or chemical state of the capsule shell material in response to environmental conditions. For example, the shell may undergo phase transitions or chemical reactions that alter its permeability properties. This allows the same capsule formulation to exhibit different release behaviors under different conditions, enabling both slow and fast release modes as needed.
2Speed
If the shell porosity is increased to enhance active ingredient release, then the release rate improves, but the insulation capability decreases leading to crystallization
Solution Approach 1:
The invention applies dynamics by making the shell porosity dynamically adjustable rather than fixed during manufacturing. The shell structure can reversibly change its pore size or openness in response to environmental stimuli, allowing it to maintain high porosity when release is needed while preserving structural integrity and insulation properties when release should be minimized, thus preventing crystallization.
Solution Approach 2:
The invention utilizes parameter changes by modifying the physical state or chemical properties of the shell material to control porosity. Environmental factors such as temperature, pH, or moisture content can trigger changes in the shell's structural parameters, dynamically adjusting porosity to balance release rate and stability requirements.
3Speed
If the capsule size is reduced to modify release profile, then the release characteristics change, but the manufacturing complexity increases
Solution Approach 1:
The invention utilizes parameter changes by modifying the chemical composition or physical state of the shell material rather than relying solely on size variations. By changing parameters such as polymer type, cross-linking density, or additive composition, the release profile can be tuned without requiring complex size-based manufacturing processes, thus maintaining manufacturing simplicity while achieving desired release characteristics.
4Speed
If thin shells are used to improve active ingredient release, then the release rate increases, but the shell breaks causing complete and sudden release
Solution Approach 1:
The invention applies composite materials by combining multiple materials with complementary properties in the capsule shell. The shell may consist of a base polymer matrix reinforced with more robust materials or structured in a composite architecture that provides both thin-wall characteristics for high release rate and enhanced mechanical strength to prevent rupture, ensuring reliable controlled release.
Solution Approach 2:
The invention applies dynamics by creating a shell structure that can dynamically adjust its mechanical properties. The shell may undergo stiffening or reinforcement in response to stress or environmental conditions, allowing it to maintain integrity during handling and application while still enabling controlled release when intended.
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 adjustment of the release rate of microencapsulated active ingredients, enhancing biological efficacy and application flexibility by changing the solvent ratio, which can significantly increase the release of active ingredients when diluted, thereby improving the effectiveness of herbicides, insecticides, and fungicides.
Implementation Method 1
In these compositions the release of the active ingredient from the capsule takes place by the diffusion of the active ingredient (a.i.) through the capsule shells
Implementation Method 2
preparation of a water-emulsifiable liquid, component B), comprising a solvent of the active ingredient and at least one surfactant
Data Source
AI summary
A method for modulating the release rate of microencapsulated active ingredients comprising the following steps: I) preparation of an aqueous suspension A) comprising microcapsules of at least one active ingredient, II) preparation of a liquid emulsifiable in water, component B), comprising a solvent of the active ingredient and at least a surfactant, III) water, component C), for diluting to the application dose the active ingredient, and mixing A), B) and C).