Polydisulfide Core-Shell Microcapsule Shell Stability

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Solution Overview

Problem

The perfumery industry faces challenges with the rapid loss of olfactive benefits due to the high volatility of odoriferous compounds, particularly 'top-notes'. Existing microcapsule delivery systems struggle with chemical stability in challenging bases, leading to leakage and reduced impact when triggered.

Innovation Solution

A process for preparing polydisulfide core-shell microcapsules involves dissolving a polythiol monomer in a hydrophobic material to form an oil phase, which is then dispersed into an aqueous phase to create an oil-in-water emulsion. Thiol oxidation at the oil-water interface, induced by an oxidant and catalyst, forms a polydisulfide shell around the hydrophobic core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional microcapsule delivery systems are used, then the perfume is delivered to the consumer, but the chemical stability is poor leading to leakage and reduced impact

Engineering Contradiction:

Improvechemical stabilityVSAvoidleakage

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The invention changes the chemical composition parameters of the shell material by using polydisulfide bonds instead of conventional polymer shells. This parameter change in the shell chemistry provides superior chemical stability against surfactants and challenging bases, preventing leakage while maintaining controlled release capabilities.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention employs a composite structure with a hydrophobic core containing perfume and a polydisulfide shell. This composite material design combines the encapsulation benefits of microcapsules with the chemical stability of polydisulfide bonds, creating a delivery system that resists degradation in challenging consumer product environments.

Inventive Principle:

Principle #40Composite materials

2Productivity

If high levels of surfactant detergents are used in consumer products, then cleaning performance is improved, but the diffusion speed of actives increases leading to leakage

Engineering Contradiction:

Improvecleaning performanceVSAvoiddiffusion speed

Core Design Contradiction:

ProductivityVSSpeed

Solution Approach 1:

The invention changes the shell material parameters to polydisulfide composition, which creates a more chemically stable barrier that reduces the diffusion speed of perfume actives even in the presence of high surfactant levels. This parameter change allows the system to withstand aggressive cleaning environments without premature release.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The polydisulfide shell provides preliminary protection against surfactant-induced degradation and premature diffusion. By pre-establishing this chemically stable barrier before the microcapsules encounter challenging consumer product bases, the system prevents the harmful acceleration of diffusion that would otherwise occur with conventional shells.

Inventive Principle:

Principle #9Preliminary anti-action

3Object-affected harmful factors

If eco-friendly materials are used in delivery systems, then biodegradability is improved, but chemical stability may be compromised

Engineering Contradiction:

ImprovebiodegradabilityVSAvoidchemical stability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention changes the shell material parameters to use polydisulfide bonds formed from polythiol monomers, which can be derived from renewable resources. This parameter change enables the creation of biodegradable yet chemically stable shell materials that do not compromise on performance in challenging consumer product environments.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The polydisulfide shell material is designed to be biodegradable, allowing it to break down into harmless byproducts after use. This discarding principle enables eco-friendly disposal while the polydisulfide structure maintains chemical stability during the product's service life, resolving the contradiction between environmental friendliness and performance.

Inventive Principle:

Principle #34Discarding and recovering

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 polydisulfide core-shell microcapsules offer improved chemical stability and reduced leakage, maintaining olfactive performance and extending the release of perfumes in consumer products.

Implementation Method 1

applying sufficient conditions to induce thiol oxidation at the oil-water interface to form a polydisulfide core-shell microcapsule slurry

Methodology Applied

Scientific EffectThiol oxidation: Oxidation

Implementation Method 2

dissolving at least one polythiol monomer in a hydrophobic material, preferably a perfume oil, to form an oil phase

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 3

dispersing the oil phase obtained in step a) into an aqueous phase to form an oil-in-water emulsion

Methodology Applied

Scientific EffectEmulsion formation: Emulsion

Data Source

PatentUS20250033015A1Polydisulfide core-shell microcapsules

Publication Date: 2025.01.30 FIRMENICH SA

AI summary

Disclosed herein is a process for the preparation of polydisulfide core-shell microcapsules. The polydisulfide core-shell microcapsules include an oil-based core including a hydrophobic material and a polymeric shell including polydisulfide bonds. Polydisulfide core-shell microcapsules are also disclosed herein. A perfuming composition and a consumer product including polydisulfide core-shell microcapsules are also disclosed herein.