Fragrance Microcapsule Shell Composition and Polymerization Control
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Solution Overview
Problem
Volatile fragrances in laundry and cosmetic formulations are prone to evaporation and unwanted interactions with other ingredients, leading to a loss of fragrance intensity and stability, which existing microcapsule technologies do not adequately address in terms of imperviousness and controlled release.
Innovation Solution
Microcapsules with a shell composed of C1-C24 alkyl esters of acrylic or methacrylic acid, bi- or polyfunctional monomers, and other ethylenically unsaturated monomers, produced through suspension polymerization at specific shear rates and stirring times, providing improved protection and controlled release of fragrances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microcapsules are used to encapsulate fragrances, then fragrance distribution and protection are improved, but fragrance leakage and volatility are not sufficiently prevented
Solution Approach 1:
The patent employs a shell composed of polymeric material formed from specific monomers (acrylic acid, methacrylic acid, and their esters) that provides flexible yet effective encapsulation. This shell structure is designed to be impermeable to volatile fragrance compounds while allowing controlled release under specific conditions such as rubbing or washing, thereby preventing fragrance leakage during storage and transport.
Solution Approach 2:
The microcapsule shell is constructed as a composite material system combining multiple monomeric components (acrylic acid, methacrylic acid, C1-C24 alkyl esters of these acids) in specific ratios. This composite polymeric structure provides enhanced barrier properties against fragrance volatility while maintaining flexibility and controlled release capabilities, addressing the insufficiency of single-material shells.
2Ease of operation
If fragrances are added to formulations, then pleasant smell is achieved, but fragrance intensity is lost due to evaporation and interactions
Solution Approach 1:
The patent extracts the fragrance compound from direct contact with other formulation ingredients by encapsulating it within microcapsules. This separation protects the volatile fragrance from unwanted interactions with surfactants and other chemicals while maintaining the ability to deliver pleasant smell when the microcapsules are activated during use such as rubbing or washing.
Solution Approach 2:
The microcapsule shell acts as a preliminary protective barrier that prevents fragrance evaporation and chemical interactions before the fragrance is needed. This preliminary protection maintains fragrance intensity and stability during storage and formulation, with release occurring only when specific triggering conditions are met during application.
3Reliability
If existing microcapsule technologies are used, then fragrance encapsulation is achieved, but imperviousness and controlled release are not adequately provided
Solution Approach 1:
The patent achieves precise control over fragrance release by carefully controlling the composition parameters of the shell material, specifically the ratios of acrylic acid, methacrylic acid, and their C1-C24 alkyl esters. By adjusting these compositional parameters, the microcapsules provide both adequate imperviousness during storage and controlled release under specific conditions, overcoming the limitations of existing technologies with fixed compositions.
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 effectively prevent fragrance evaporation and ensure a slow or on-demand release, maintaining fragrance intensity and stability in formulations.
Implementation Method 1
incorporate the fragrances or perfumes in microcapsules into the formulations. These microcapsules enable the valuable fragrance or perfume to be distributed relatively homogeneously in a formulation, without having to expose it to the other constituents during storage.
Implementation Method 2
Suitable selection of the shell of the capsule also allows effects to be achieved in this way such as retarded release or release on demand upon rubbing.
Data Source
AI summary
The present invention relates to a carrier system for fragrances, to the production thereof and to the use of the carrier system in laundry and cosmetic formulations.Accordingly, the present invention is directed to a microcapsule comprising a core of hydrophobic material composed of at least one fragrance or perfume and a microcapsule shell obtainable by the suspension polymerization of the following monomers:(a) one or more C1-C24-alkyl ester(s) of (meth)acrylic acid (monomer A),(b) one or more bi- or polyfunctional monomers (monomer B) and(c) optionally, one or more other ethylenically unsaturated monomers (monomer C), wherein the shear rate for the preparation of the emulsion lies in the range of from 150 to 500 rpm and the stirring time for the preparation of the emulsion lies in the range of from 15 min to 180 min.