Multi-Layer Coolant Tube Composition for Hydrolysis and Sealability
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Solution Overview
Problem
Existing multi-layer coolant tubes for motor vehicles face challenges in providing adequate mechanical strength, resistance to hydrolysis, creep stress cracking, and sealability while maintaining economic viability, particularly in medium temperature applications.
Innovation Solution
A multi-layer tube comprising a polyamide outer layer, a polyolefin intermediate layer, and a thermoplastic elastomeric inner layer, where the polyamide outer layer provides mechanical strength and environmental protection, the polyolefin intermediate layer shields against hydrolysis, and the thermoplastic elastomeric inner layer prevents creep stress cracking and ensures excellent sealability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyamide outer layer is used to provide mechanical strength and burst pressure resistance, then the tube exhibits good hoop strength and environmental protection, but the polyamide layer is susceptible to hydrolytic degradation when in contact with water/coolant
Solution Approach 1:
The tube is divided into three functional layers: an outer polyamide layer for mechanical strength, an intermediate polyolefin layer for hydrolysis protection, and an inner thermoplastic elastomeric layer for sealability. This segmentation allows each layer to specialize in one function without compromising the others.
Solution Approach 2:
The polyolefin intermediate layer serves as a protective intermediary between the polyamide outer layer and the coolant environment. It shields the polyamide from water contact, preventing hydrolytic degradation while allowing the polyamide to maintain its mechanical strength properties.
2Reliability
If a polyolefin inner layer is used to protect the polyamide from hydrolysis, then the tube gains resistance to hydrolytic degradation, but the polyolefin layer exhibits reduced creep stress cracking resistance and forms microcracks allowing coolant leakage
Solution Approach 1:
The tube structure segments the protective function from the structural function. The polyolefin layer handles hydrolysis protection while the thermoplastic elastomeric inner layer provides creep stress cracking resistance, eliminating the need for polyolefin to perform both functions simultaneously.
Solution Approach 2:
The thermoplastic elastomeric inner layer acts as an intermediary that protects the polyolefin intermediate layer from stress cracking. This inner layer absorbs mechanical stresses and prevents crack formation, allowing the polyolefin to focus on hydrolysis protection without compromising structural integrity.
3Device complexity
If a single-layer tube material is used to simplify construction, then manufacturing cost is reduced, but it is difficult to provide all essential properties (mechanical strength, hydrolysis resistance, creep resistance, and sealability) in a single material
Solution Approach 1:
The invention uses a composite multi-layer structure combining polyamide, polyolefin, and thermoplastic elastomeric materials. Each material contributes its superior properties to the overall tube performance, creating a composite structure that exceeds the capabilities of any single material.
Solution Approach 2:
The tube is segmented into three layers, each optimized for a specific function: mechanical strength, hydrolysis protection, and creep resistance with sealability. This functional segmentation allows the use of cost-effective materials for each specific purpose rather than requiring an expensive single material to perform all functions.
4Strength
If the tube structure is optimized for high burst pressure resistance using polyamide, then mechanical strength is improved, but the tube exhibits poor sealability for fitted connections including barbed connections
Solution Approach 1:
The tube structure segments the structural function from the sealing function. The outer polyamide-polyolefin layers provide mechanical strength and hoop strength, while the inner thermoplastic elastomeric layer specifically provides sealability for fitted and barbed connections.
Solution Approach 2:
The inner layer made of thermoplastic elastomeric material provides localized quality optimized for sealing applications. This material offers the flexibility and conformability needed for excellent sealability at connection points, while the outer layers maintain the overall structural integrity and hoop strength of the tube.
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 multi-layer tube effectively transports coolant at medium temperatures, offering improved burst pressure resistance, sealability, and hoop strength, reducing the risk of leaks and pipe failure, while being economical and suitable for both electrical and internal combustion vehicles.
Implementation Method 1
the polyolefin intermediate layer 16 shields the polyamide from contact with water to avoid hydrolytic degradation
Implementation Method 2
guards against stress cracking in the polyolefin intermediate layer 16
Data Source
Figure 1~2
Figure 3~4
AI summary
The present disclosure provides a multi-layer tube comprising a polyamide outer layer, a polyolefin intermediate layer and a thermoplastic elastomeric inner layer. The polyamide outer layer provides sufficient mechanical strength and the polyolefin intermediate layer shields the polyamide from contact with water to avoid hydrolytic degradation. The thermoplastic elastomeric inner layer guards against stress cracking in the polyolefin intermediate layer and provides an excellent seal for connection.