Crosslinked Microcapsule Walls for Low Evaporation Heat Storage
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Solution Overview
Problem
Conventional microcapsules used in textiles and building materials for latent heat storage suffer from high evaporation rates and washout losses due to insufficient density, leading to inefficiencies in temperature regulation and material integrity.
Innovation Solution
Development of microcapsules with a capsule wall composed of 30-90% C1-C24 alkyl esters of acrylic and/or methacrylic acid, 10-70% divinyl and polyvinyl monomers, and 0-30% other monomers, with a predominantly lipophilic core, achieving a stable particle size distribution and enhanced chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional microcapsules are used in textiles and building materials, then latent heat storage function is provided, but high evaporation rate occurs leading to loss of encapsulated material
Solution Approach 1:
The capsule wall is constructed as a composite polymer system comprising at least two different polymers: a first polymer (30-90 wt%) providing baseline properties and a second polymer (10-70 wt%) contributing enhanced density and barrier characteristics. This composite structure achieves low evaporation rates while maintaining structural integrity, resolving the contradiction between preventing material loss and ensuring reliable capsule performance.
Solution Approach 2:
The invention specifies precise compositional parameters for the capsule wall polymers, including weight ratios (30-90% first polymer, 10-70% second polymer), molecular weight ranges, and functional group characteristics. By optimizing these parameters, the capsule wall achieves sufficient density to prevent evaporation while maintaining manufacturing feasibility and operational reliability.
2Loss of substance
If conventional microcapsules are used for latent heat storage, then temperature regulation function is achieved, but washout losses occur during chemical cleaning indicating insufficient density
Solution Approach 1:
The dual-polymer composite wall structure provides enhanced density and chemical resistance compared to single-polymer systems. The synergistic combination of two polymers with different properties creates a more robust barrier that resists washout during chemical cleaning processes, while maintaining the encapsulated core intact and preventing substance loss.
3Productivity
If microcapsules with small particle size are produced for textile applications, then fiber impregnation is improved, but maintaining stable particle size distribution becomes more difficult
Solution Approach 1:
The invention controls particle size distribution through precise parameter specification: average particle size of 0.5-100 μm with narrow distribution, and polymer composition ratios (30-90% first polymer, 10-70% second polymer). These controlled parameters enable small capsule sizes suitable for textile impregnation while maintaining stable and uniform particle size distribution throughout production.
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 a low evaporation rate and improved chemical cleaning resistance, maintaining structural integrity and effective heat storage performance across various applications.
Implementation Method 1
The microcapsules exhibit a low evaporation rate
Implementation Method 2
a capsule wall made up of C 1 -C 24 alkyl esters of acrylic and/or methacrylic acid, acrylic acid, methacrylic acid and/or maleic acid, crosslinkers
Data Source
AI summary
The invention relates to microcapsules comprising a core and a wall, the capsule wall consisting of between 30 and 90 wt. % of at least one C1-C24 alkyl ester of acrylic and/or methacrylic acid, acrylic acid, methacrylic acid and/or maleic acid (monomers I), between 10 and 70 wt. % of a mixture of divinyl and polyvinyl monomers (monomers II), the part of polyvinyl monomers amounting to between 2 and 90 wt % in relation to the monomers II, and between 0 and 30 wt. % of at least one other monomer (monomer III) respectively in relation to the total weight of the monomers. The invention also relates to a method for producing said microcapsules, and to the use thereof in textiles, binding building materials and heat transfer liquids.