Urethane and refrigerator comprising same
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Solution Overview
Problem
Conventional urethane adiabatic materials used in refrigerators have high thermal conductivity, exceeding environmental regulations, and increasing thickness compromises storage capacity, necessitating a high-performance urethane with lower thermal conductivity.
Innovation Solution
A urethane with a composition of 90% closed cells and 10% open cells, featuring cell diameters of 100 to 200 μm, and cell walls connecting them, manufactured by controlling reaction rates through a specific ratio of polyol solution, isocyanate, blowing agent, foam stabilizer, and catalysts to achieve reduced thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of urethane is increased to improve thermal insulation, then thermal insulation performance is improved, but the size of the refrigerator increases and storage capacity decreases
Solution Approach 1:
The patent changes the physical and chemical parameters of the urethane material itself, specifically achieving a thermal conductivity of 18.0 to 20.5 mW/m·K through controlled cell structure (100-200 μm diameter closed cells with specific wall thickness), rather than changing the thickness parameter. This allows maintaining standard refrigerator dimensions while improving insulation performance.
Solution Approach 2:
The patent creates a composite cellular structure within the urethane consisting of closed cells (90% or more by volume) containing blowing agent residues, open cells (10% or less by volume) for moisture evacuation, and cell walls with specific thickness (0.35-0.5 μm). This composite microstructure achieves superior thermal insulation properties enabling thinner overall insulation layers.
2Ease of manufacture
If conventional urethane is used to meet current insulation requirements, then manufacturing is simple, but thermal conductivity is too high (20 mW/m·K) to satisfy environmental regulations
Solution Approach 1:
The patent modifies key parameters of the conventional urethane formulation and processing: blowing agent quantity (30 parts by weight or less based on 100 parts polyol), cell diameter (100-200 μm), cell wall thickness (0.35-0.5 μm), and density (30-35 kg/m³). These parameter changes reduce thermal conductivity to 18.0-20.5 mW/m·K while maintaining compatibility with existing injection molding processes.
Solution Approach 2:
The patent utilizes a controlled porous cellular structure with specific characteristics: closed cells containing blowing agent residues, open cells for moisture evacuation, and optimized cell wall thickness. This porous structure reduces thermal conductivity by creating air pockets that impede heat transfer, achieving 18.0 to 20.5 mW/m·K thermal conductivity while remaining manufacturable through conventional foam injection processes.
3Loss of energy
If the cell diameter is reduced to improve thermal insulation, then thermal conductivity decreases, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies an optimal cell diameter range of 100-200 μm that balances thermal insulation performance with manufacturability. This parameter, combined with cell wall thickness of 0.35-0.5 μm and density of 30-35 kg/m³, achieves thermal conductivity of 18.0-20.5 mW/m·K while being achievable through conventional foam injection processes with standard catalyst and blowing agent formulations.
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 urethane achieves a thermal conductivity of 18.0 to 20.5 mW/m·K, improving thermal insulation by 10% compared to conventional urethanes, resulting in energy-saving effects of 5% or more.
Implementation Method 1
forming cells by adding a blowing agent and a foam stabilizer for cell formation
Implementation Method 2
A thermal conductivity λurethane may be about 18.0 to 20.5 mW/m·K
Implementation Method 3
a plurality of closed cells containing inside gas; a plurality of open cells connected to outside air
Data Source
AI summary
Disclosed are a urethane having improved thermal insulation performance by lowering thermal conductivity of the urethane and a refrigerator comprising the same. The urethane may comprise: a plurality of closed cells containing inside gas; a plurality of open cells connected to outside air; and cell walls disposed between at least one of the plurality of closed cells and at least one of the plurality of open cells or between the plurality of closed cells to connect the at least one of the plurality of closed cells with the at least one of the plurality of open cells or to connect the plurality of closed cells. Diameters of a closed cell of the plurality of closed cells and an open cell of the plurality of open cells may be about 100 to 200 μm.