laminate
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Solution Overview
Problem
Heat exchange sheets used in total heat exchangers have insufficient moisture permeability, particularly in low temperature and low humidity environments, which affects their performance in separating and exchanging heat between supply and exhaust air.
Innovation Solution
A laminate comprising a porous substrate with a moisture-permeable membrane formed from a thermoplastic copolymer containing a hydrophilic betaine group and a hydrophobic functional group, providing low air permeability and enhanced moisture permeability, even in low temperature and low humidity conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydrophilic polymer compound (polymer of compound having quaternary ammonium group and amide group) is used to improve moisture permeability, then moisture permeability is enhanced, but moisture permeability in low temperature and low humidity environment becomes insufficient
Solution Approach 1:
The invention changes the chemical structure parameters of the polymer by introducing a betaine group-containing side chain. This structural modification enables the material to maintain high moisture permeability across a broader range of environmental conditions, particularly in low temperature and low humidity environments where conventional hydrophilic polymers fail.
Solution Approach 2:
The invention creates a composite structure by combining the betaine group-containing side chain with a polyolefin main chain. This composite material approach integrates the hydrophilic properties of the betaine group with the hydrophobic and structurally stable polyolefin backbone, achieving both high moisture permeability and environmental adaptability.
2Reliability
If calcium chloride or lithium chloride moisture-permeable membrane is used to achieve high moisture permeability, then moisture permeability is improved, but water resistance becomes poor due to high solubility
Solution Approach 1:
The invention changes the material composition from inorganic salts (calcium chloride, lithium chloride) to an organic polymer with betaine group-containing side chains. This parameter change maintains high moisture permeability while dramatically improving water resistance and compositional stability.
Solution Approach 2:
The invention replaces the short-lived, water-soluble inorganic salt membranes with a durable, water-resistant polymer membrane that maintains its functional properties over extended periods and under various humidity conditions.
3Reliability
If low molecular weight compound (sulfuric acid or sodium hydroxide) is used to form moisture-permeable membrane, then moisture permeability is enhanced, but water resistance deteriorates due to poor water resistance of the compound
Solution Approach 1:
The invention creates a composite structure where the betaine group-containing side chain provides hydrophilic pathways for moisture transport, while the polyolefin main chain provides hydrophobic matrix for water resistance. This composite approach simultaneously achieves high moisture permeability and excellent water resistance.
Solution Approach 2:
The invention changes from using low molecular weight compounds to a polymer system with specific molecular weight and structure (betaine group-containing side chain on polyolefin backbone), achieving both enhanced moisture permeability and improved water resistance through the synergistic combination of hydrophilic and hydrophobic components.
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 laminate achieves excellent moisture permeability and low air permeability, making it suitable for use as a partition member in total heat exchange elements, effectively exchanging temperature and moisture between supply and exhaust air while maintaining air separation.
Implementation Method 1
a moisture-permeable membrane formed of a thermoplastic copolymer having a side chain containing a hydrophilic group which is a functional group. The hydrophilic group is preferably a betaine group
Implementation Method 2
The copolymer preferably further contains a hydrophobic functional group in a side chain
Data Source
AI summary
The present disclosure provides a laminate having low air permeability and excellent moisture permeability, a partition member for total heat exchange element composed of the laminate, a total heat exchange element provided with a plurality of the partition members for total heat exchange element, and a ventilation device provided with the total heat exchange element. The laminate of the present disclosure is provided with a porous substrate and a moisture-permeable membrane disposed on one side of the porous substrate, the moisture-permeable membrane being provided with a porous substrate and a moisture-permeable membrane disposed on at least one side of the porous substrate, and the moisture-permeable membrane being formed of a thermoplastic copolymer having a side chain containing a hydrophilic group which is a functional group.