Core-Shell Microcapsules With Cross-Linked Coacervate Shells
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Solution Overview
Problem
Existing protein-based microcapsules for fragrance encapsulation suffer from instability in water-based products, permeability issues, and large particle sizes, limiting their use in consumer products.
Innovation Solution
A process involving cross-linking proteins with a first cross-linking agent, followed by the addition of polysaccharides to form a coacervate, stabilizing core composition droplets, and forming a shell that enhances imperviousness and control over microcapsule size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gelatin-based microcapsules are formed by conventional coacervation process, then encapsulation is achieved, but the microcapsules swell in water-based products and become permeable to fragrance ingredients
Solution Approach 1:
The patent changes the chemical parameters of the shell by introducing cross-linking agents (isocyanates, aldehydes, or polyfunctional nucleophiles) that react with gelatin to form cross-linked networks. This chemical modification reduces shell permeability and prevents swelling in water-based products, thereby resolving the contradiction between encapsulation stability and fragrance permeability.
Solution Approach 2:
The patent creates a composite shell structure combining gelatin with cross-linking agents and optionally polysaccharides. This composite approach maintains the biodegradability and biocompatibility of gelatin while adding the permeability control and stability benefits of cross-linked networks, solving both encapsulation reliability and harmful permeability issues simultaneously.
2Reliability
If cross-linking is performed after coacervation formation, then shell stability is improved, but the process complexity increases and manufacturing efficiency decreases
Solution Approach 1:
The patent performs cross-linking during the coacervation process itself, before the shell is fully formed. The cross-linking agent is introduced in the aqueous phase before or during the coacervate formation step, allowing cross-linking to occur concurrently with shell formation. This preliminary action eliminates subsequent separate cross-linking steps, reducing process complexity while maintaining shell stability.
Solution Approach 2:
The patent merges the coacervation process with the cross-linking process into a single integrated operation. Both shell formation and cross-linking occur simultaneously in one reaction vessel without requiring separate process steps, thereby improving manufacturing efficiency while achieving stable cross-linked shells.
3Adaptability or versatility
If conventional coacervation process is used, then protein-based encapsulation is achieved, but the microcapsule size is large (median size in the order of 600 μm)
Solution Approach 1:
The patent changes physical parameters of the emulsion system by controlling core droplet size through emulsification conditions and adjusting coacervation parameters (pH, ionic strength, temperature) to optimize shell formation. These parameter modifications enable precise control over microcapsule size, reducing median size from 600 μm to below 75 μm while maintaining protein-based encapsulation.
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 process produces microcapsules with improved stability and controlled size, preventing leakage and better deposition on substrates, suitable for use in water-based consumer products.
Implementation Method 1
the shell is formed by cross-linking of at least one protein with a first cross-linking agent, followed by the addition of at least one polysaccharide to form a complex coacervate
Implementation Method 2
addition of at least one polysaccharide to form a complex coacervate
Data Source
AI summary
The present invention relates to a process for obtaining an encapsulated composition, to encapsulated compositions obtainable by this process, to products comprising these encapsulated compositions and to the use of these encapsulated compositions to provide consumer products.