Acrylic Microcapsule Wall Composition for Low Evaporation
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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 capsule tightness, which affects their durability and performance in thermal applications.
Innovation Solution
Microcapsules with a capsule wall composed of 30% to 90% C1-C24-alkyl esters of acrylic and/or methacrylic acid, 10% to 70% divinyl and polyvinyl monomers, and 0% to 30% miscellaneous monomers, produced through in situ polymerization, achieving a low evaporation rate and improved durability by controlling the particle size distribution and core-to-wall ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional microcapsule structures are used, then ease of manufacture is maintained, but evaporation rate increases and capsule tightness deteriorates
Solution Approach 1:
The capsule wall is constructed as a composite material system comprising multiple monomer components (30-90% C1-C24-alkyl esters of acrylic and/or methacrylic acid, 10-70% divinyl and polyvinyl monomers, and 0-30% miscellaneous monomers) that work synergistically to achieve both low evaporation rates and high capsule tightness, resolving the contradiction between reliability and energy loss
Solution Approach 2:
The invention optimizes specific compositional parameters of the capsule wall, including the weight percentages of different monomer types and the core-to-wall ratio, to control the polymerization process and resulting capsule properties, thereby achieving improved reliability without excessive energy loss during manufacturing
2Reliability
If conventional microcapsule compositions are used, then manufacturing simplicity is maintained, but washout loss increases
Solution Approach 1:
The multi-component monomer composition creates a composite capsule wall structure with enhanced mechanical and chemical properties that resist washout during textile processing, achieving durability improvement while maintaining manufacturing feasibility through in situ polymerization
Solution Approach 2:
The capsule wall composition is optimized to provide specific local properties at the capsule surface and throughout the wall structure, creating regions with different monomer concentrations that collectively enhance resistance to washout while maintaining overall capsule integrity
3Reliability
If high crosslinking density is used, then capsule tightness improves, but manufacturing complexity increases
Solution Approach 1:
The invention achieves high capsule tightness by optimizing the parameter of crosslinking density within specific ranges (10-70% divinyl and polyvinyl monomers) rather than using maximum crosslinking, and implements this through a relatively simple in situ polymerization process that avoids complex manufacturing steps
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 described microcapsules exhibit a low evaporation rate and enhanced durability, maintaining thermal performance over a wide range of capsule sizes, thereby addressing the issues of washout losses and thermal stability in both textile and building material applications.
Implementation Method 1
a capsule wall being constructed from 30% to 90% by weight of one or more C1-C24-alkyl esters of acrylic and/or methacrylic acid, acrylic acid, methacrylic acid and/or maleic acid (monomers I), 10% to 70% by weight of a mixture of divinyl and polyvinyl monomers (monomers II)
Implementation Method 2
The working principle of latent heat storage media, often also known as phase change materials (PCMs), relies on the transformation enthalpy which arises during the solid/liquid phase transition and which signifies an absorption of energy or release of energy to the environment
Implementation Method 3
the transformation enthalpy which arises during the solid/liquid phase transition
Data Source
AI summary
The present invention concerns microcapsules comprising a capsule core and a capsule wall, the capsule wall being constructed from30% to 90% by weightof one or more C1-C24-alkyl esters of acrylic and/or methacrylic acid, acrylic acid, methacrylicacid and/or maleic acid (monomers I),10% to 70% by weightof a mixture of divinyl and polyvinyl monomers(monomers II), the fraction of polyvinylmonomers being in the range from 2% to 90%by weight based on the monomers II, and also 0% to 30% by weightof one or more miscellaneous monomers(monomer III),all based on the total weight of the monomers, a process for their production and their use in textiles, bindered building materials and heat transfer fluids.