Polyurethane Chafe Layer for Heat- and Chemical-Resistant Fluid Lines

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Solution Overview

Problem

Existing fluid lines in the automotive sector face challenges in withstanding high temperatures, chemical resistance, and mechanical stability, particularly in engine compartments, where they are exposed to fuels, oils, coolants, and other chemicals, and require enhanced abrasion protection to prevent damage and leakage.

Innovation Solution

A fluid line with a thermoplastic polyurethane abrasion protection layer, comprising polycarbonate polyol, diol as a chain extender, and isocyanate, applied via extrusion or coextrusion, providing a durable and flexible outer layer with improved heat stability, hydrolysis resistance, and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional abrasion protection layers are used, then basic protection is provided, but the fluid line fails to withstand high temperatures and chemical exposure in engine compartments

Engineering Contradiction:
Improveresistance to high temperature and chemical exposureVSAvoiddamage from heat, chemicals, and abrasion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies composite materials by formulating an abrasion protection layer using a specific composition: thermoplastic polyurethane as the base polymer, polycarbonate polyol as the polyol component, and 1,4-butanediol as the chain extender. This composite material composition provides simultaneous resistance to high temperatures (up to 150°C), chemical exposure (fuels, oils, coolants), and abrasion, resolving the contradiction between basic protection and enhanced reliability under extreme conditions.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs parameter changes by optimizing the molecular structure and composition of the polyurethane polymer. Specifically, it uses polycarbonate polyol with controlled molecular weight and composition, combined with specific ratios of chain extenders, to achieve a material that maintains mechanical properties at elevated temperatures and exhibits improved chemical resistance, thereby enhancing reliability under thermal and chemical stress.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the abrasion protection layer is made thicker to improve durability, then abrasion resistance increases, but the fluid line becomes less flexible and harder to install

Engineering Contradiction:
Improveabrasion resistanceVSAvoidflexibility and installability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent resolves this contradiction through parameter changes in the polymer composition, specifically by using 1,4-butanediol as a chain extender in controlled amounts (0.5-5 parts by weight per 100 parts polyol). This creates a polyurethane with optimized molecular weight and chain structure that provides high abrasion resistance while maintaining flexibility and elongation properties, allowing the fluid line to be both durable and easy to install.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality by creating an abrasion protection layer with specific compositional characteristics concentrated at the outer surface where abrasion occurs, while the inner layers maintain flexibility. The graded structure ensures that the hardest, most abrasion-resistant composition is at the exterior, while flexibility is preserved in the overall conduit structure.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If standard polyurethane formulations are used, then processing is simple, but the material lacks sufficient hydrolysis resistance and long-term stability

Engineering Contradiction:
Improveprocessing simplicityVSAvoidhydrolysis resistance and long-term stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies composite materials by combining polycarbonate polyol with specific chain extenders and additives in a formulated composition. This composite approach creates a polyurethane that exhibits superior hydrolysis resistance and long-term stability compared to standard formulations, while remaining processable through conventional extrusion and molding techniques. The specific combination of polycarbonate polyol and 1,4-butanediol creates a material that resists degradation in humid and chemically aggressive environments.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent uses readily available, commercially standard chemicals (polycarbonate polyol, 1,4-butanediol, isocyanate) that can be procured and processed using existing industrial infrastructure, avoiding the need for expensive proprietary materials or complex specialized processing equipment, thereby maintaining ease of manufacture while achieving enhanced performance.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 ensures the fluid line maintains its integrity and functionality under extreme conditions, withstanding high temperatures and chemical exposure, while ensuring long-term durability and resistance to abrasion, hydrolysis, and microbial attack.

Implementation Method 1

improved heat stability

Methodology Applied
Scientific EffectThermal stability:

Implementation Method 2

hydrolysis resistance

Methodology Applied
Scientific EffectHydrolysis resistance: Hydrolysis

Implementation Method 3

resistance to abrasion

Methodology Applied
Scientific EffectAbrasion resistance: Abrasion

Implementation Method 4

applied via extrusion or coextrusion

Methodology Applied
Scientific EffectExtrusion: Extrusion

Data Source

PatentEP4172223B1Fluid conduit, method for producing a fluid conduit and use of a polyurethane as a chafe layer and use of an ethylene copolymer as an additive
Publication Date: 2024.04.03 AFT AUTOMOTIVE
  • EP4172223B1 patent drawingFigure 1~2
  • EP4172223B1 patent drawingFigure 3~4

AI summary

The invention relates to a chafe layer (9) for a fluid conduit (1), wherein the chafe layer (9) consists of thermoplastic polyurethane which contains polyol, in particular short-chained, diol as a chain extender and isocyanate. It is envisaged that the polyol is a polycarbonate. The invention also relates to a fluid conduit (1), a method for producing a fluid conduit (1) as well as the use of a polyurethane and the use of an ethylene copolymer as an additive.