Microcapsule Curing Process for Fragrance Retention
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Solution Overview
Problem
Existing fragrance encapsulation technologies face challenges in maintaining the retention of active materials in consumer products, particularly in aqueous bases containing surfactants, leading to premature leaching and reduced longevity of the fragrance.
Innovation Solution
A process for preparing high-stability microcapsules involves curing a crosslinked network of polymers containing fragrances at temperatures above 90°C, with a linear heating profile and extended curing time, to enhance retention and stability in consumer products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fragrance materials are encapsulated in polymeric coatings to protect from evaporation and oxidation, then fragrance retention is improved, but the capsule shell becomes permeable to core contents when stored in aqueous bases containing surfactants, leading to leaching
Solution Approach 1:
The patent changes the physical-chemical parameters of the capsule shell by curing it at elevated temperatures (above 90°C) to transform the polymeric coating from a permeable state to a crosslinked network state. This parameter change fundamentally alters the shell's properties, making it impermeable to fragrance materials while maintaining integrity in surfactant-containing aqueous bases.
Solution Approach 2:
The invention creates a composite structure by forming a crosslinked polymer network within the capsule shell. This crosslinked network combines multiple polymer chains through covalent bonds, creating a unified composite material that exhibits enhanced resistance to leaching and improved fragrance retention compared to the uncured polymeric coating.
2Duration of action of stationary object
If conventional encapsulation is used, then fragrance protection is achieved, but sensory performance deteriorates after repeated wash and rinse cycles
Solution Approach 1:
The patent applies preliminary action by curing the capsule shell before the fragrance is intended to be released. The crosslinking process is performed in advance during manufacturing, creating a stable, impermeable shell that will maintain fragrance retention throughout subsequent wash and rinse cycles, ensuring consistent sensory performance.
Solution Approach 2:
The crosslinked network structure serves as a protective cushioning mechanism that prevents fragrance loss beforehand. By creating this robust shell structure in advance, the patent cushions against the harmful effects of surfactants and mechanical stress during washing, ensuring fragrance materials remain retained until intentionally released.
3Adaptability or versatility
If microcapsules are stored in aqueous bases with surfactants, then consumer product functionality is achieved, but active material diffuses from core to media over time
Solution Approach 1:
The patent applies preliminary anti-action by pre-curing the capsule shell to create an impermeable barrier before exposure to surfactant-containing aqueous bases. This preliminary protective action counteracts the leaching effect that would otherwise occur when microcapsules are stored in consumer products, preventing active material diffusion while maintaining product compatibility.
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 process significantly improves the retention of fragrances, allowing for greater than 40% retention after four weeks, and maintains sensory performance and stability during wash and rinse cycles, even in surfactant-containing bases.
Implementation Method 1
The polymeric material is used to protect the fragrance material from evaporation, reaction, oxidation or otherwise dissipating prior to use
Implementation Method 2
The overall leaching mechanism may be viewed as a diffusion process, with transfer occurring from the capsule core to the aqueous media
Implementation Method 3
it is clear that the partitioning favors absorption by the surfactant over time
Implementation Method 4
curing at a temperature above 90°C a crosslinked network of polymers containing an active material which is a fragrance
Data Source
AI summary
The present invention is directed to a process for preparing a capsule product through the increase in the polymerization cure temperature and cure time during the capsule-making process. The microcapsule products prepared according the process of the present invention exhibit enhanced retention of active materials in consumer products which promote instability.