Biodegradable Microcapsules via Epoxide-Polyamine Shell
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Solution Overview
Problem
The fragrance industry faces challenges with the rapid evaporation and dissipation of volatile fragrance compounds due to their high volatility, and existing microencapsulation methods often use non-biodegradable materials that are harmful to the environment and human health, lacking in oxidative stability and control over release properties.
Innovation Solution
Development of biodegradable core-shell microcapsules with a shell formed from a biobased epoxide, specifically diglycidyl ether diphenolic ester, and a polyamine, which provides stability and controlled release of fragrances without using isocyanates or melamine-formaldehyde systems, suitable for use in consumer products like laundry detergents and fabric conditioners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spray drying is used for microencapsulation, then manufacturing simplicity and low cost are achieved, but oxidative stability deteriorates due to high temperatures
Solution Approach 1:
The invention changes the temperature parameter during microencapsulation from high temperatures (spray drying) to low temperatures (freeze drying), thereby preserving oxidative stability while maintaining manufacturing feasibility. The low temperature parameter prevents thermal oxidation of fragrance compounds during the encapsulation process.
Solution Approach 2:
The invention replaces the thermal-mechanical spray drying process with a cryogenic freeze drying process. This substitution eliminates the harmful thermal effects while achieving microencapsulation, using freezing and sublimation mechanisms instead of heat-based atomization and drying.
2Stability of the object's composition
If freeze drying is used for microencapsulation, then oxidative stability is improved, but release control deteriorates due to high porosity
Solution Approach 1:
The invention uses a composite polymer shell structure comprising multiple polymer components with different properties. This composite structure allows optimization of both oxidative stability and release control by combining materials that provide barrier properties with those that enable controlled fragrance release, overcoming the limitations of single-material approaches.
Solution Approach 2:
The invention creates local quality variations within the microcapsule shell by incorporating polymers with different permeability characteristics in specific regions or layers. This allows the shell to exhibit both high oxidative stability (through impermeable barrier layers) and controlled release properties (through selectively permeable regions), addressing the contradiction between stability and release control.
3Quantity of substance
If coacervation is used for microencapsulation, then encapsulation efficiency is improved, but wall strength deteriorates due to non-covalent interactions
Solution Approach 1:
The invention applies preliminary action by forming a strong polymeric shell structure before encapsulating the fragrance material. The polymer shell is pre-formed with covalent bonds providing structural strength, and then the fragrance is encapsulated within this robust framework, ensuring both high encapsulation efficiency and strong wall strength.
Solution Approach 2:
The invention changes the bonding parameter from non-covalent interactions (coacervation) to covalent bonding (polymerization). By using polymerization reactions to form the shell, the invention achieves both high encapsulation efficiency and strong wall strength, as covalent bonds provide superior mechanical strength compared to weak non-covalent interactions.
4Strength
If interfacial polymerization is used for microencapsulation, then wall strength is improved, but environmental harm increases due to toxic reactants
Solution Approach 1:
The invention converts harmful toxic reactants into beneficial non-toxic alternatives. Instead of using isocyanates and formaldehyde which are harmful to health and environment, the invention employs water and carbon dioxide as reactants to form the polymer shell. This converts a potentially harmful chemical process into an environmentally benign one, maintaining wall strength while eliminating toxicity.
Solution Approach 2:
The invention introduces water as an intermediary substance that mediates the polymerization reaction to form the shell. Water acts as a safe alternative to toxic isocyanates, enabling the formation of strong polymeric walls through hydrolysis and condensation reactions without exposing workers or the environment to harmful chemicals.
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 biodegradable microcapsules offer improved stability and controlled release of fragrances, reducing environmental impact and human health risks while maintaining fragrance persistence and consumer acceptance.
Implementation Method 1
Interfacial polymerization typically involves reactions between oil-soluble and water-soluble components to form polymeric microcapsules
Implementation Method 2
Ideally, the core material is protected from the surrounding environment (e.g., heat, oxygen, moisture, UV radiation, interaction with other materials)
Implementation Method 3
the polymer films, formed exclusively by non-covalent ionic interactions and phase separation, result in low strength of microcapsule walls
Data Source
AI summary
This disclosure relates to biodegradable core-shell microcapsule compositions wherein the microcapsule shell contains a polymer formed with a biobased epoxide and a polyamine. This disclosure also relates to a method of preparing such biodegradable core-shell microcapsules. This disclosure also relates to consumer products containing such biodegradable core-shell microcapsules.