Microencapsulation via Wax Phase Transition
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Solution Overview
Problem
Current microencapsulation processes face challenges in controlling particle size, achieving energy efficiency, and maintaining product characteristics, particularly for applications requiring particle sizes less than 50 micrometers, and often involve chemical reactions or energy-intensive methods.
Innovation Solution
A process involving heating a fatty phase with wax and an active ingredient, then forming a stable oil-in-water emulsion with a water-soluble surfactant and protective colloid, followed by dropwise addition into a second aqueous phase at a lower temperature to create microcapsules with controlled size between 2 and 80 micrometers, without chemical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional microencapsulation processes are used, then chemical reactions or energy-intensive methods are involved, but this increases environmental impact and process complexity
Solution Approach 1:
The invention extracts and eliminates chemical reactions from the microencapsulation process, using purely physical phase transition mechanisms instead. This removes harmful chemical factors while maintaining encapsulation functionality through wax melting and solidification cycles.
Solution Approach 2:
The process utilizes temperature parameter changes to control wax phase transitions. By cycling temperature above and below the wax melting point, the system achieves encapsulation and release without chemical reactions, reducing environmental impact while simplifying the process.
2Manufacturing precision
If particle size control is achieved through conventional methods, then energy-intensive procedures are required, but this increases energy consumption
Solution Approach 1:
The invention employs phase transitions of the wax material as the core mechanism for particle formation and size control. The wax melts at elevated temperature allowing emulsion formation, then solidifies upon cooling to define particle size, eliminating the need for energy-intensive mechanical size reduction methods.
Solution Approach 2:
The process replaces mechanical size control methods (such as milling or homogenization) with a thermal-field-based approach. Temperature-controlled phase transitions naturally define particle dimensions during the encapsulation process, significantly reducing energy consumption while maintaining precision.
3Duration of action of stationary object
If microcapsules are produced for long-lasting release applications, then specific technologies are required, but this increases device complexity
Solution Approach 1:
The invention uses the phase transition properties of the wax matrix to control active ingredient release duration. The wax remains solid at use temperature, providing a stable matrix for long-lasting release, and melts at elevated temperature to enable controlled discharge, achieving extended duration without complex multi-layer structures.
Solution Approach 2:
The process creates composite microcapsules combining a wax matrix with encapsulated active ingredient. This composite structure provides both the structural integrity needed for long-term stability and the thermal-responsive release mechanism, achieving extended duration in a relatively simple single-phase system.
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 method allows for the production of microcapsules with precise size control, improved stability, and reduced energy consumption, enabling their use in various applications such as cosmetics and agrochemicals while minimizing environmental impact.
Implementation Method 1
heating a fatty phase with wax and an active ingredient
Implementation Method 2
cold crystallization step
Data Source
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AI summary
The present invention relates to a method for producing a dispersion of microcapsules of active ingredient, in suspension in water, comprising the following successive steps: heating a fatty phase comprising at least (i) a wax, and at least one active ingredient to be encapsulated, at a reaction temperature above the melting point of said wax; heating a first aqueous phase comprising at least one water-soluble surfactant and at least one protective colloid; incorporating said fatty phase into said first aqueous phase while maintaining the reaction temperature, so as to form a stable oil-in-water emulsion; adding, dropwise, said emulsion previously formed to a second aqueous phase comprising at least one water-soluble surfactant, the temperature of said second phase being below the melting point of said wax and resulting in the formation of solid crystalline microcapsules containing said active ingredient, said microcapsules being in suspension in said second aqueous phase. The invention also relates to the use of the microcapsules obtained at the end of the process, (i) for producing a cosmetic composition or (ii) for producing impregnated fabrics or (iii) for producing household products.