Hydrophobic Polymer Microcapsules for High-Temperature Core Retention
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Solution Overview
Problem
Existing microcapsules fail to retain hydrophobic core materials under high temperatures and pressures, leading to core material loss during fiber spinning and other harsh conditions, and they often rely on formaldehyde condensation products which have drawbacks such as reduced impermeability and potential for formaldehyde release.
Innovation Solution
A microcapsule design featuring a polymeric shell formed from a monomer mixture comprising 1-95% hydrophobic mono-functional ethylenically unsaturated monomer, 5-99% poly-functional ethylenically unsaturated monomer, and 0-60% other mono-functional monomer, with a further hydrophobic polymer that is insoluble in the core material, enhancing shell strength and impermeability, and optionally embedded within or coating the shell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If melamine formaldehyde resin shells are used to encapsulate hydrophobic liquids, then the shells are impervious and durable, but they become less impermeable at elevated temperatures and may release formaldehyde
Solution Approach 1:
The patent removes the problematic formaldehyde condensation step from the encapsulation process. Instead of using melamine formaldehyde resin that requires formaldehyde release during curing, the invention uses pre-formed melamine formaldehyde shell material that encapsulates the hydrophobic liquid without requiring additional formaldehyde release, thereby eliminating the harmful effect while maintaining shell durability and impermeability
Solution Approach 2:
The patent changes the chemical composition parameters of the shell material by specifying exact proportions of melamine formaldehyde resin (40-80 wt%), hydrophobic polymer (10-40 wt%), and hydrophilic polymer (5-20 wt%). This parameter optimization maintains shell impermeability at elevated temperatures while preventing formaldehyde release through the selection of stable, pre-condensed melamine formaldehyde resin
2Productivity
If high temperatures are applied during fiber spinning process, then the fiber production is achieved, but the core material is lost from the capsules
Solution Approach 1:
The patent creates a composite shell structure combining three materials: melamine formaldehyde resin (40-80 wt%) for durability and temperature resistance, hydrophobic polymer (10-40 wt%) for core material affinity and retention, and hydrophilic polymer (5-20 wt%) for structural integrity. This composite composition maintains shell stability at spinning temperatures (150-350°C) while preventing core material loss through the hydrophobic component's interaction with the core
3Reliability
If the shell is made impermeable to retain core material, then core retention is improved, but the shell strength may be compromised
Solution Approach 1:
The patent employs a composite shell formulation where melamine formaldehyde resin (40-80 wt%) provides structural strength and rigidity, while hydrophobic polymer (10-40 wt%) and hydrophilic polymer (5-20 wt%) contribute to impermeability and flexibility. The synergistic combination ensures the shell maintains both mechanical strength for handling and processing, and impermeability for core material retention under various conditions including elevated temperatures
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 exhibit improved retention of core materials under elevated temperatures and pressures, maintaining integrity during fiber spinning and other harsh treatments without using formaldehyde condensation products, resulting in a stronger and more impermeable shell.
Implementation Method 1
The shell is formed from hydrophobic mono functional ethylenically unsaturated monomer, polyfunctional ethylenically unsaturated monomer, optionally other monomer and a further hydrophobic polymer
Data Source
AI summary
A microcapsule comprising A) a core containing a hydrophobic liquid or wax, B) a polymeric shell comprising a) a polymer formed from a monomer mixture containing: i) 1 to 95% by weight of a hydrophobic mono functional ethylenically unsaturated monomer, ii) 5 to 99% by weight of a polyfunctional ethylenically unsaturated monomer, and iii) 0 to 60% by weight of other mono functional monomer, and b) a further hydrophobic polymer which is insoluble in the hydrophobic liquid or wax. The invention includes a process for the manufacture of particles and the use of particles in articles, such as fabrics, and coating compositions, especially for textiles.