Melamine-Free Polyurea-Urethane Microcapsules for Surfactant Stability
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Solution Overview
Problem
The perfumery industry faces challenges with the rapid loss of olfactive benefits due to volatility, particularly of 'top-notes', and existing microcapsules suffer from stability issues in surfactant-based consumer products, leading to inefficient controlled release of fragrances.
Innovation Solution
A process for preparing melamine-formaldehyde free poly(urea-urethane) microcapsules using an anionic bio-sourced polyol and a specific protic acid catalyst, without the use of amines or polyamines, to create stable microcapsules that maintain fragrance delivery in challenging product bases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyurea-based microcapsules are used to replace aminoplast capsules, then formaldehyde-free and improved stability are achieved, but mechanical properties deteriorate (less friable, reduced odor intensity)
Solution Approach 1:
The patent changes the chemical parameters of the capsule wall composition by using polyurethane polymers with specific molecular weights (1,000-1,000,000 Da) and controlled NCO index (0.5-2.0), along with specific acid catalysts (pKa 2-6), to achieve both stability and mechanical properties. This parameter optimization resolves the contradiction between stability and friability.
Solution Approach 2:
The invention creates a composite capsule wall system combining polyurethane polymer, acid catalyst, and water to form a multi-component structure that achieves both chemical stability in surfactant environments and appropriate mechanical friability for olfactive performance.
2Strength
If melamine-formaldehyde capsules are used, then good mechanical properties and controlled release are achieved, but stability in surfactant-based products deteriorates due to active leakage
Solution Approach 1:
The patent extracts and eliminates the melamine-formaldehyde resin system from the capsule wall composition, replacing it with polyurethane-based materials that do not suffer from surfactant-induced active leakage, while maintaining mechanical properties through careful polymer selection.
Solution Approach 2:
The invention changes the chemical composition parameters by using polyurethane polymers with specific molecular weights and NCO indices, along with acid catalysts, to create a capsule wall that is inherently resistant to surfactant penetration and active leakage.
3Reliability
If polyamine components are used in capsule preparation, then oil leakage is reduced and stability is improved, but application scope is limited due to component intolerance
Solution Approach 1:
The patent removes polyamine components from the capsule preparation process entirely, replacing them with polyurethane polymers and acid catalysts that achieve similar stability and leakage prevention without the component intolerance issues, thereby expanding application scope.
4Quantity of substance
If traditional microcapsule delivery systems are used, then fragrance protection is achieved, but rapid loss of olfactive benefit occurs due to volatility
Solution Approach 1:
The patent uses polyurethane polymer-based capsule walls with controlled thickness and porosity (through NCO index and molecular weight selection) that provide flexible yet effective barriers against fragrance volatility, enabling controlled release while maintaining olfactive benefits.
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 solution provides stable and effective delivery of fragrances in surfactant-based consumer products, ensuring prolonged odor perception and improved mechanical properties without the use of melamine-formaldehyde, thus addressing the industry's demand for regulatory compliance and performance.
Implementation Method 1
performing a polycondensation reaction between said at least one polyisocyanate and at least one anionic bio-sourced polyol in the presence of at least one protic acid catalyst
Implementation Method 2
forming an emulsion with the oligomeric composition, an oil and a cross-linker
Data Source
AI summary
The present invention relates to a new process for the preparation of melamine- formaldehyde free microcapsules. Microcapsules obtainable by said process are also an object of the invention. Perfuming compositions and consumer products comprising said capsules, in particular perfumed consumer products in the form of home care or personal care products, are also part of the invention.