Polyketone Barrier Layer for Insulated Conduit Gas Diffusion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thermally insulated line pipes face issues with gas diffusion due to the decomposition of polyvinylidene dichloride (PVDC) at high temperatures and the humidity-dependent barrier properties of ethylene vinyl alcohol (EVOH), leading to increased thermal conductivity and safety concerns in continuous production processes.
Innovation Solution
A thermally insulated line pipe with a barrier layer made of polyketones or polyether ketones, which are more stable and effective at high temperatures, eliminating the need for adhesion promoters and maintaining barrier properties across varying humidity conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVDC barrier layer is used, then gas barrier properties are improved, but decomposition occurs at high temperatures during production
Solution Approach 1:
The patent changes the material parameter from PVDC to polyketone, which maintains excellent gas barrier properties while being stable at extrusion temperatures of 170-190°C, eliminating decomposition issues
Solution Approach 2:
The patent uses a polymeric barrier layer that can be processed together with the jacket material in continuous production, replacing the need for separate metallic barrier layers and simplifying the production process
2Reliability
If EVOH barrier layer is used, then gas barrier properties are improved, but barrier effect becomes highly dependent on humidity
Solution Approach 1:
The patent changes the material from EVOH to polyketone, which provides consistent gas barrier properties across varying humidity conditions without the strong humidity dependence characteristic of EVOH
3Reliability
If EVOH barrier layer is used, then gas barrier properties are improved, but adhesion promoter is always necessary
Solution Approach 1:
The patent combines the barrier layer and jacket layer into a single coextruded structure, eliminating the need for separate adhesion promoter layers and simplifying the manufacturing process
Solution Approach 2:
The polyketone barrier layer serves both as a gas barrier and as an adhesive layer, eliminating the need for separate adhesion promoters and reducing the total number of layers required
4Reliability
If PVDC barrier layer is used, then gas barrier properties are improved, but decomposition releases harmful gases
Solution Approach 1:
The patent changes the material from PVDC to polyketone, which has a decomposition temperature above 200°C and does not release harmful gases at the extrusion temperatures of 170-190°C used in continuous 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 polyketone barrier layer provides excellent gas barrier properties against nitrogen, carbon dioxide, and water vapor, reducing thermal conductivity and ensuring safety in continuous production processes without the need for additional adhesion promoters, thus enhancing the efficiency and safety of thermally insulated line pipes.
Implementation Method 1
the gas composition of the polyurethane foam (PU foam), which generally used as insulation material, changes over time. This is done by diffusion of nitrogen and oxygen from the air into the foam and by diffusion of the foam or cell gases originally contained in the foam, in particular carbon dioxide, out of the foam.
Implementation Method 2
water vapor is also completely prevented from diffusing. This is problematic when using inner pipes made of plastic, as mostly warm water flows through them permanently, which is why a constant amount of water vapor, even if only a small amount, migrates through their walls.
Data Source
Figure 1~5
Figure 3~4
AI summary
When manufacturing a thermally insulated conduit comprising an inner tube (2), thermal insulation (20) and an outer sleeve (13), a barrier made of a polymer that contains or consists of polyketones is used. A conduit of said type is protected against gas diffusion and is easy to manufacture.