Multilayer Polyamide Tube Structure for Recycled Automotive Fluid Pipes

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Solution Overview

Problem

End-of-life automotive pipes, particularly those used for transporting fluids, degrade due to severe thermo-oxidative environments and loss of plasticizers, making them unsuitable for reuse, contributing to waste and global warming, while car manufacturers aim for 100% recycling to minimize environmental impact.

Innovation Solution

A multilayer tubular structure comprising at least three layers: one layer with a composition of recycled polyamide resins predominantly comprising aliphatic and aromatic units, and two layers of semi-crystalline aliphatic polyamides, including impact modifiers, to create a durable pipe suitable for fluid transport in vehicles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If end-of-life automotive pipes are reused directly, then waste reduction is achieved, but the pipes fail due to thermo-oxidative degradation and plasticizer loss

Engineering Contradiction:
Improvewaste reductionVSAvoidpipe durability
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The patent recovers polyamide material from end-of-life pipes through shredding and granulation, then reprocesses it into new multilayer pipes with enhanced stability. The recycled polyamide is discarded from its degraded original form and recovered as a raw material for new applications, achieving both waste reduction and reliable performance through chemical stabilization

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The patent changes the chemical parameters of the recycled polyamide by adding stabilizers, antioxidants, and UV absorbers during reprocessing. These parameter changes restore and enhance the material's thermo-oxidative stability, allowing the recycled material to meet durability requirements for new automotive pipe applications

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If end-of-life pipes are incinerated for energy recovery, then energy is produced, but global warming is exacerbated

Engineering Contradiction:
Improveenergy recoveryVSAvoidglobal warming emissions
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

Instead of incinerating the pipes for energy recovery, the patent recovers the polyamide material through mechanical processing and reprocesses it into new pipe products. This material recovery approach eliminates the need for incineration, thereby avoiding greenhouse gas emissions while still utilizing the resource value of the end-of-life pipes

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The patent transforms the end-of-life pipes from a waste stream destined for incineration into a valuable recycled material source. By changing the processing parameters from thermal combustion to mechanical recycling with chemical stabilization, the system recovers both material and energy value without generating harmful emissions

Inventive Principle:
Principle #35Parameter changes

3Loss of substance

If multilayer structure with recycled material is used, then waste reduction is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improverecycled material utilizationVSAvoidmultilayer structure complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent segments the pipe structure into multiple layers with different functions: an inner layer in contact with fluid, a middle layer with recycled polyamide for structural integrity, and an outer layer for environmental protection. This segmentation allows each layer to be optimized for its specific function while utilizing recycled material in the critical structural layer

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a composite multilayer structure combining recycled polyamide with stabilizers, antioxidants, and UV absorbers. This composite approach enhances the performance of the recycled material while managing the complexity through standardized manufacturing processes for multilayer extrusion and coating

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS12398268B2Multilayer structure based on recycled polyamide
Publication Date: 2025.08.26 ARKEMA FRANCE SA

AI summary

A multilayer tubular structure for transporting fluids for a motor vehicle, including at least three layers: at least one layer having a composition predominantly including at least one semi-crystalline aliphatic polyamide, the composition having at least 50% of recycled material from a multilayer tube that has been intended for transporting fluids for a motor vehicle, the tube having a composition which predominantly includes at least one polyamide, at least one layer having a composition predominantly including at least one semi-crystalline aliphatic polyamide and optionally at least one impact modifier, and when the layer has a composition predominantly including at least one semi-crystalline aliphatic polyamide that is PA12 and/or PA612 and/or PA1010, then the composition includes the impact modifier, and at least one layer having a composition predominantly including at least one semi-crystalline aliphatic polyamide, the layer and the layer each having at least 90% of non-recycled material.