Photopolymer Microcapsules With Controlled Shear for Stable Retention
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Solution Overview
Problem
Existing encapsulation methods for active ingredients in formulated products suffer from stability issues and performance decline due to adverse reactions with other components, leading to poor retention and mechanical stability of capsules.
Innovation Solution
A continuous process for preparing microcapsules with a cross-linked photopolymer shell, involving a double emulsion and controlled shear rate followed by irradiation, to enhance retention and mechanical stability, achieving monodispersity and high conversion of reactive groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encapsulation methods (spray-drying, interfacial polymerisation, solvent evaporation) are used to isolate active ingredients, then encapsulation is achieved, but retention properties are insufficient and mechanical stability deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the shell material by using photopolymerizable compositions that undergo photopolymerization to form cross-linked networks. This cross-linking structure fundamentally alters the mechanical and retention properties of the capsule shell, providing both high retention capability and mechanical strength simultaneously
Solution Approach 2:
The patent employs composite material structures by combining photopolymerizable monomers, cross-linking agents, and photoinitiators within the emulsion system. The resulting cross-linked photopolymer shell represents a composite structure that integrates multiple functional components to achieve superior retention and mechanical properties
2Reliability
If photopolymerization is applied to form cross-linked shells, then retention and mechanical stability improve, but capsule breakage and droplet coalescence may occur
Solution Approach 1:
The patent applies preliminary action by pre-forming the double emulsion with properly sized droplets and appropriate composition before irradiation. The controlled shear rate step prepares the emulsion structure in advance, ensuring that when photopolymerization occurs, the capsules are already positioned and structured to resist breakage and coalescence
Solution Approach 2:
The patent controls the photopolymerization process by adjusting irradiation parameters (intensity, duration, wavelength) and chemical composition (monomer to cross-linker ratio, photoinitiator concentration) to achieve optimal conversion without excessive stress on the capsule structure, preventing breakage while maintaining cross-linked shell integrity
3Productivity
If continuous processing is implemented for large-scale manufacture, then productivity increases, but homogeneity of capsule characteristics may deteriorate
Solution Approach 1:
The patent implements continuous processing where the emulsion is continuously fed through the irradiation zone and reaction medium. This continuous operation maintains consistent conditions throughout the process, ensuring homogeneous capsule formation while enabling large-scale manufacturing. The continuous nature of the process eliminates batch-to-batch variations
Solution Approach 2:
The patent incorporates monitoring and control mechanisms that provide feedback on reaction progress and capsule formation. By adjusting flow rates, irradiation intensity, and residence time based on real-time observations, the system maintains homogeneous capsule characteristics throughout continuous production
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 enables large-scale production of capsules with excellent retention properties and improved homogeneity, substantially preventing capsule breakage and droplet coalescence, while maintaining high conversion of reactive groups.
Implementation Method 1
irradiating the mixed double emulsion C4 to prepare the microcapsules
Data Source
AI summary
A continuous process for preparing microcapsules having an active ingredient encapsulated in a shell of cross-linked photopolymer which includes providing a double emulsion comprising droplets of at least one active ingredient (C1) dispersed in a photopolymerizable composition C2, said droplets being dispersed in a composition C3, the compositions C2 and C3 being immiscible with each other; inducing a controlled shear rate in said double emulsion to provide a mixed double emulsion (C4); and irradiating the mixed double emulsion (C4) to prepare the microcapsules.