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Solution Overview
Problem
Existing encapsulated perfumery compositions face challenges with colloidal stability in diverse consumer products, particularly in those with varying pH and ionic surfactants, leading to aggregation and phase separation.
Innovation Solution
The development of an encapsulated composition featuring core-shell microcapsules with a shell comprising a thermosetting resin formed from a polyfunctional amine and a polyfunctional isocyanate, combined with a cationic polymer and a polymeric stabilizer with fully or partially dissociated carboxylic acid groups, maintaining a specific molar ratio to ensure optimal colloidal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microcapsules are formulated with stable shell chemistry and well-designed perfume core, then fragrance leakage and release performance are improved, but colloidal stability in products with ionic surfactants and varying pH deteriorates
Solution Approach 1:
The shell is constructed as a composite material combining thermosetting resin (formed from polyfunctional amine and polyfunctional isocyanate) with polymeric stabilizer containing carboxylic acid groups. This composite structure integrates the fragrance-retention properties of the resin with the colloidal-stability properties of the carboxylic acid groups, resolving the contradiction between fragrance leakage control and colloidal stability.
Solution Approach 2:
The invention changes the chemical parameters of the shell by incorporating polymeric stabilizers with carboxylic acid groups that can dissociate. The nominal molar ratio of amino groups and quaternary ammonium groups to carboxylic acid groups is controlled within 0.8-1.1, allowing the shell to adapt its charge state and colloidal behavior across varying pH conditions while maintaining structural integrity for fragrance retention.
2Stability of the object's composition
If microcapsules are designed for broad pH range stability, then colloidal stability is improved, but manufacturing complexity increases
Solution Approach 1:
The polymeric stabilizer with carboxylic acid groups serves multiple functions simultaneously: it provides colloidal stability across broad pH ranges through dissociation, contributes to shell structure formation, and enables electrostatic repulsion between microcapsules. This multi-functionality reduces the need for separate additives and simplifies the overall formulation process despite the sophisticated performance requirements.
3Stability of the object's composition
If polymeric stabilizer with carboxylic acid groups is added to achieve colloidal stability, then aggregation is prevented, but the number of components and formulation complexity increases
Solution Approach 1:
The polymeric stabilizer is merged with the shell-forming materials themselves rather than being added as a separate functional component. The carboxylic acid-containing polymers are incorporated into the shell matrix during the encapsulation process, combining the structural and stabilizing functions in a single integrated layer, thereby reducing the number of discrete components in the final formulation.
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 solution achieves optimal colloidal stability of microcapsules across a broad pH range and in the presence of various surfactants, preventing aggregation and phase separation, while ensuring effective fragrance release and retention.
Implementation Method 1
a shell surrounding the core, wherein the shell comprises a thermosetting resin formed by reaction of a polyfunctional amine comprising at least one amino group with at least one polyfunctional isocyanate
Implementation Method 2
The shell further comprises a polymeric stabilizer comprising fully or partially dissociated carboxylic acid groups
Data Source
AI summary
Disclosed is an encapsulated composition comprising at least one core-shell microcapsule. The at least one core-shell microcapsule comprises a core containing at least one perfume ingredient and a shell surrounding the core. The shell comprises a thermosetting resin formed by reaction of a polyfunctional amine comprising at least one amino group with at least one polyfunctional isocyanate. The shell further comprises a cationic polymer comprising quaternary ammonium groups. The shell further comprises a polymeric stabilizer comprising fully or partially dissociated carboxylic acid groups. The nominal molar ratio of the amino groups and the quaternary ammonium groups to the carboxylic acid groups is from 0.9 to 1.1, preferably from 0.95 to 1.08, more preferably from 1.00 to 1.06.