Amine modified polysaccharide urethane/urea microcapsules
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Solution Overview
Problem
Existing microencapsulation technologies face challenges in simplifying the process, improving microcapsule wall performance and durability, enhancing adherence and deposition, and ensuring degradability, particularly in the use of starch-based materials.
Innovation Solution
The development of amine modified polysaccharide microcapsules formed through interfacial polymerization, using amine modified polysaccharides, such as hydrophobically modified starches, reacted with isocyanates to create cross-linked polyurethane/urea shells, in a one-step or two-step oil-in-water process, with specific mole and weight ratios of reactants to achieve robust microcapsules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If starch-based materials are used for microencapsulation, then natural and renewable components are utilized, but process simplification and wall performance improvement are challenged
Solution Approach 1:
The patent modifies the physical and chemical parameters of starch by amination reactions, transforming it into amine-modified polysaccharides that can participate in interfacial polymerization with isocyanates. This parameter change enables starch to form cross-linked polyurethane/urea walls while maintaining its natural origin, thus resolving the contradiction between using renewable components and achieving manufacturability
Solution Approach 2:
The invention creates composite microcapsule walls combining amine-modified polysaccharides (from natural starch) with synthetic polyurethane/urea components formed through interfacial polymerization. This composite approach allows the microcapsules to benefit from both the renewability of starch and the performance characteristics of cross-linked polymer walls, addressing the contradiction between natural material usage and manufacturing ease
2Reliability
If complex interfacial polymerization processes are used, then microcapsule wall performance and durability are improved, but process complexity increases
Solution Approach 1:
The patent performs preliminary amination modification of starch before the microencapsulation process. This preliminary action introduces amino groups into the starch structure, enabling it to directly participate in interfacial polymerization with isocyanates without requiring additional complex steps during capsule formation, thus improving wall performance while managing process complexity
Solution Approach 2:
The amine-modified polysaccharide acts as an intermediary that bridges the natural starch material and the synthetic polyurethane/urea wall formation process. It enables the interfacial polymerization reaction to occur effectively between the aqueous phase containing modified starch and the organic phase containing isocyanates, simplifying the overall process while ensuring robust wall formation
3Strength
If cross-linked polyurethane/urea shells are formed through interfacial polymerization, then microcapsule strength and controlled release are improved, but degradability may be compromised
Solution Approach 1:
The patent creates local quality differentiation within the microcapsule wall by using amine-modified polysaccharides that provide specific functional groups for cross-linking at critical locations. The cross-linked polyurethane/urea structures form in regions where strength is needed, while the polysaccharide backbone maintains degradability pathways, thus achieving both strength and controlled degradability simultaneously
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 improved physical properties, controlled release of benefit agents, and enhanced degradability, while utilizing natural and renewable components, suitable for various applications.
Implementation Method 1
Interfacial polymerization is a process wherein a microcapsule wall of polyamide, an epoxy resin, a polyurethane, a polyurea or the like is formed at an interface between two phases
Implementation Method 2
reacted with isocyanates to create cross-linked polyurethane/urea shells
Implementation Method 3
The amine diffuses to the interface, where it reacts with the diisocyanate to form polymeric polyurethane shells
Implementation Method 4
polymerization occurs at the phase boundary. Thus, a polymeric capsule shell wall forms at the interface of the two phases thereby encapsulating the core material
Data Source
AI summary
Core shell microcapsules are provided wherein the capsule shell is an interfacial copolymer formed of an amine modified polysaccharide cross-linked with an isocyanate.