Solid Microcapsule Shell with Sub-Nanometer Pores for Active Ingredient Retention
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Solution Overview
Problem
Existing capsule technologies for active ingredients in formulated products suffer from limited retention properties, leading to leakage and instability, which compromises the performance and stability of the encapsulated substances over time.
Innovation Solution
A method for preparing solid microcapsules with a core containing an active ingredient and a solid enveloping shell less than 1 nm in pore size, achieved through a process involving the controlled emulsification and crosslinking of specific polymeric compositions, eliminating the need for surfactants and ensuring long-term retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capsule manufacturing methods (spray-drying, interfacial polymerisation, solvent evaporation) are used, then capsules can be produced with active ingredients, but the retention properties are limited leading to leakage and release of active ingredients
Solution Approach 1:
The invention changes the pore size parameter of the capsule shell to less than 1 nm through controlled polymerisation and crosslinking processes. This critical parameter change transforms the shell from permeable to impermeable, preventing active ingredient leakage while maintaining manufacturing feasibility through established polymer chemistry techniques.
Solution Approach 2:
The capsule shell is constructed as a composite polymeric material formed by polymerisation of monomers followed by crosslinking to create a dense network structure. This composite approach combines the benefits of polymer flexibility with crosslinked structural integrity, achieving both retention properties and manufacturing ease.
2Reliability
If the capsule shell is made impermeable to retain active ingredients, then retention properties improve, but the manufacturing process becomes more complex requiring precise control of polymerisation and crosslinking
Solution Approach 1:
The invention performs preliminary polymerisation of monomers to form oligomers or low molecular weight polymers before crosslinking. This preliminary action creates a precursor structure that is easier to control and process, allowing subsequent crosslinking to achieve the desired <1 nm pore size without requiring extremely precise control of the entire process at once.
Solution Approach 2:
The invention uses crosslinking agents as intermediaries that bridge polymer chains to form the dense crosslinked network. These crosslinking agents act as mediators that control the formation of the impermeable structure, allowing gradual and controlled achievement of the target pore size rather than requiring direct formation of the final structure.
3Stability of the object's composition
If conventional capsules are used, then active ingredients can be encapsulated, but leakage occurs leading to decline in performance and stability over time
Solution Approach 1:
The invention changes the pore size parameter to less than 1 nm through controlled polymerisation and crosslinking, transforming the shell from permeable to impermeable. This critical parameter change prevents active ingredient leakage while maintaining stability, directly resolving the contradiction between retention and stability.
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 resulting microcapsules exhibit excellent retention capabilities, significantly slowing down or preventing the diffusion of compounds larger than 1 nm, thereby maintaining the integrity and performance of the active ingredients for extended periods.
Implementation Method 1
the polymerisation of the composition C2, whereby solid microcapsules dispersed in the composition C3 are obtained
Implementation Method 2
the composition C2 comprising at least one monomer or polymer having an average molecular weight of less than 5000 g.mol−1, at least one crosslinking agent having an average molecular weight of less than 5000 g.mol−1
Implementation Method 3
an emulsion (E1) is obtained comprising droplets of the composition C1 dispersed in the composition C2
Data Source
AI summary
The present invention relates to a capsule preparation method for preparing solid microcapsules, comprising the following steps:a) addition, under agitation, a composition C1, comprising at least one active ingredient, to a polymeric composition C2, the compositions C1 and C2 being mutually immiscible, whereby an emulsion (E1) is obtained comprising droplets of the composition C1 dispersed in the composition C2;b) addition, under agitation, the emulsion (E1) to a composition C3, the compositions C2 and C3 being mutually immiscible, whereby a double emulsion (E2) is obtained comprising droplets dispersed in the composition C3;c) applying shear to the emulsion (E2), whereby a double emulsion (E3) is obtained comprising size controlled droplets dispersed in the composition C3; andd) polymerising the composition C2, whereby solid microcapsules dispersed in the composition C3 are obtained.