Ampholyte Copolymer Stabilizer for Fragrance Microcapsule Charge Stability
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Solution Overview
Problem
Current encapsulated perfume compositions lack commercial viability due to instability, poor deposition, and inadequate olfactive performance, despite extensive research on microcapsules for home and personal care applications.
Innovation Solution
The use of an ampholyte copolymer as a colloidal stabilizer during the preparation of polyurea or polyurethane shell microcapsules, which imparts a stable positive charge to the microcapsules without affecting their physical stability or olfactive performance, by forming a stable complex with anionically modified isocyanates and polyamines or polyfunctional alcohols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cationic polymers or quaternary ammonium compounds are used as deposition aids to impart positive charge to microcapsules, then deposition on substrate is enhanced, but the positive charge is not stable and can be washed off during manufacturing
Solution Approach 1:
The patent combines the colloidal stabilizer function and the deposition aid function into a single ampholyte copolymer. The copolymer contains both anionic groups (for colloidal stabilization during manufacturing) and cationic groups (for deposition on substrate). This merging eliminates the need for separate deposition aids and ensures the positive charge is permanently integrated into the microcapsule structure, solving the instability problem of prior art cationic polymers.
Solution Approach 2:
The ampholyte copolymer is a composite material containing both anionic and cationic functional groups within the same polymer chain. This composite structure allows the polymer to perform dual functions: stabilizing the emulsion during microcapsule formation through anionic interactions, and providing stable positive charge for deposition through cationic interactions. The composite nature ensures both manufacturing ease and charge stability.
2Reliability
If extensive research is conducted on microcapsules for home and personal care applications, then olfactive performance can be improved, but commercial viability is still lacking due to instability and poor deposition
Solution Approach 1:
The ampholyte copolymer serves multiple functions simultaneously: it acts as a colloidal stabilizer during emulsion formation, provides a stable positive charge for deposition, and ensures commercial viability by preventing microparticle agglomeration. This multi-functionality addresses all the deficiencies of prior art microcapsules in a single material, achieving both stability and commercial viability.
3Manufacturing precision
If ampholyte copolymer is used as colloidal stabilizer, then emulsion stability and deposition are improved, but control over shell thickness and fragrance release must be maintained
Solution Approach 1:
The patent maintains control over shell thickness and fragrance release by adjusting parameters of the ampholyte copolymer system, such as the ratio of anionic to cationic groups, the concentration of the copolymer, and the reaction conditions during microcapsule formation. These parameter changes allow precise control of the shell properties while maintaining the dual functionality of the copolymer.
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 approach enhances the stability of the emulsion, prevents microparticle agglomeration, and ensures consistent olfactive performance, simplifying the manufacturing process and allowing precise control over microcapsule shell thickness and fragrance release rates.
Implementation Method 1
forming a stable complex with anionically modified isocyanates and polyamines or polyfunctional alcohols
Implementation Method 2
use of an ampholyte copolymer as a colloidal stabilizer in the preparation of polyurea or polyurethane shell microcapsules
Implementation Method 3
imparts a stable positive charge to the microcapsules
Data Source
AI summary
The invention relates to the use of an ampholyte copolymer as a colloidal stabilizer in the preparation of core-shell microcapsules containing a fragrance, wherein the ampholyte copolymer comprises: - 2 to 99 mol% of cationic monomer having at least one quaternary ammonium group, - 1 to 98 mol% of acrylic based monomer, - 0 to 97 mol% of non-ionic monomer, and wherein the ampholyte copolymer has more cationic charges than anionic charges, wherein the cationic charges of the ampholyte copolymer are exclusively due to the at least one quaternary ammonium group of the cationic monomer.