Multilayer Vacuum Insulation Covering for Humid Heat Barrier Stability
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Solution Overview
Problem
Vacuum heat insulation materials face challenges in maintaining heat insulation performance over long periods in high-temperature and high-humidity environments due to defects in the outer covering material's gas barrier layers, leading to gas permeation and degradation of the vacuum state.
Innovation Solution
An outer covering material comprising at least four resin layers and three gas barrier layers, with specific elastic modulus characteristics to prevent defects and maintain gas barrier properties, ensuring the vacuum state is preserved in harsh environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vacuum heat insulation material is used in a high-temperature and high-humidity environment, then the gas barrier properties of the outer covering material deteriorate over time, but the heat insulation performance needs to be maintained
Solution Approach 1:
The outer covering material uses a composite structure with at least four resin layers and three gas barrier layers. The gas barrier layers are made of inorganic materials (such as aluminum oxide, silicon oxide, or nitrogen-containing inorganic compounds) deposited on resin layers, creating a multi-layer composite that provides excellent gas barrier properties while maintaining flexibility and durability in high-temperature and high-humidity environments.
Solution Approach 2:
The outer covering material is divided into multiple functional layers: resin layers providing structural integrity and flexibility, and gas barrier layers providing impermeability to gases and water vapor. This segmentation allows each layer to perform its specific function optimally, with the gas barrier layers preventing gas permeation even under harsh environmental conditions.
2Reliability
If the outer covering material includes multiple resin layers and gas barrier layers, then the gas barrier properties improve, but the manufacturing complexity increases
Solution Approach 1:
The gas barrier layers are formed by depositing inorganic materials directly onto the resin layers in a continuous manufacturing process. This merging of the gas barrier function into the existing resin layer structure eliminates the need for separate gas barrier components, simplifying the overall manufacturing process while maintaining the multi-layer protective structure.
3Reliability
If the gas barrier layers are made of inorganic materials, then the gas barrier properties improve, but the cost of materials increases
Solution Approach 1:
The inorganic gas barrier materials are applied only in specific locations where gas barrier properties are most critical - namely on the resin layers that are most exposed to environmental conditions. This localized application of expensive inorganic materials optimizes gas barrier performance while minimizing material costs compared to using inorganic materials throughout the entire structure.
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 solution effectively maintains heat insulation performance by preventing gas permeation and sustaining the vacuum state within the vacuum heat insulation material even in high-temperature and high-humidity conditions, thereby extending the material's performance duration.
Implementation Method 1
Outer covering materials for vacuum heat insulation material require gas barrier properties of preventing gas such as oxygen and water vapor from permeating
Implementation Method 2
inside the bag body is kept in a vacuum state of which pressure is lower than the atmospheric pressure; thus, heat convection inside is suppressed to exhibit an excellent heat insulation performance
Implementation Method 3
the first resin layer is a thermally weldable film
Data Source
Figure 1~2B
Figure 3~4
Figure 5~6B
AI summary
The present disclosure provides an outer covering material for vacuum heat insulation materials, which comprises at least four resin layers, namely, a first resin layer, a second resin layer, a third resin layer and fourth resin layer, and at least three gas barrier layers, and wherein: the first resin layer is a thermally weldable film, one or more of the gas barrier layers are arranged between the second resin layer and the third resin layer; and one or more of the gas barrier layers are arranged between the third resin layer and the fourth resin layer. This outer covering material for vacuum heat insulation materials has a tensile storage elastic modulus within the range of from 1.0 * 109 Pa to 1.5 * 109 Pa (inclusive) in an atmosphere having a temperature of 70°C and a humidity of 90%RH; the indentation elastic modulus of the second resin layer is not less than the indentation elastic modulus of the first resin layer; the indentation elastic modulus of the third resin layer is not less than the indentation elastic modulus of the second resin layer; and the indentation elastic modulus of the forth resin layer is not less than the indentation elastic modulus of the third resin layer.