Polyamide Core-Shell Microcapsules for Fragrance Stability

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Solution Overview

Problem

The perfumery industry faces challenges in maintaining the stability of microcapsules containing odoriferous compounds in aggressive consumer product bases, leading to rapid loss of olfactive benefit, while there is a growing demand for eco-friendly delivery systems.

Innovation Solution

The development of polyamide core-shell microcapsules formed by reacting acyl chloride with co-oligopeptide, which are stable in challenging bases and effectively encapsulate hydrophobic materials like perfumes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional microcapsule delivery systems are used in aggressive consumer product bases, then they provide initial fragrance release, but they rapidly lose stability and dissociate physically, leading to rapid loss of olfactive benefit

Engineering Contradiction:

Improvestability of microcapsules in challenging basesVSAvoidduration of olfactive benefit

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent employs a composite shell structure comprising both polyamide and polyurea components formed through interfacial polymerization. This composite material provides enhanced chemical resistance and structural integrity in aggressive consumer product bases while maintaining controlled fragrance release over time, resolving the contradiction between stability and duration of action.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the polymerization parameters by controlling the addition rate and sequence of monomers (hexamethylene diisocyanate and diamine), adjusting the pH and temperature conditions during shell formation. These parameter changes optimize the cross-linking density and mesh structure of the shell, enabling simultaneous achievement of stability in challenging bases and sustained fragrance release.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If more aggressive stabilizing agents are used to improve microcapsule stability in challenging bases, then physical dissociation is reduced, but the eco-friendliness and biodegradability of the delivery system deteriorate

Engineering Contradiction:

Improvestability in aggressive consumer product basesVSAvoideco-friendliness and biodegradability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses water-soluble diamines as intermediary agents during the interfacial polymerization process to form the protective shell. These diamines enable the creation of a stable polyurea-polyamide composite structure without requiring aggressive cross-linking agents, maintaining biodegradability and eco-friendliness while achieving the necessary stability in challenging bases.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent achieves enhanced stability through controlled polymerization parameters rather than aggressive stabilizing agents. By optimizing the monomer ratio, addition rate, and reaction conditions, the system forms a densely cross-linked but biodegradable shell that provides protection without compromising eco-friendliness.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If traditional polyamide formation methods are used, then manufacturing simplicity is maintained, but the shell structure is insufficient to prevent physical dissociation in challenging bases

Engineering Contradiction:

Improvesimplicity of microcapsule preparationVSAvoidstability against physical dissociation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent performs preliminary selection and preparation of specific monomers (hexamethylene diisocyanate and diamine) with known reactivity and biodegradability properties before the interfacial polymerization process. This preliminary action enables the formation of a pre-designed composite shell structure that inherently provides the necessary stability while maintaining the simplicity of the one-step polymerization manufacturing process.

Inventive Principle:

Principle #10Preliminary action

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 microcapsules provide enhanced stability and olfactive performance, meeting the need for eco-friendly delivery systems that maintain fragrance release in consumer products.

Implementation Method 1

a polyamide shell comprising the reaction product between at least one acyl chloride and at least one co-oligopeptide

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

Dispersing an oil phase comprising a hydrophobic material and at least one acyl chloride into a dispersing phase to form a two-phases dispersion

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentUS20250332075A1Polyamide microcapsules

Publication Date: 2025.10.30 FIRMENICH SA

AI summary

Disclosed herein is a new process for the preparation of polyamide microcapsules. Also disclosed herein are the polyamide microcapsules. Also disclosed herein are Perfuming compositions and consumer products including the microcapsules, including in the form of home care or personal care products.