Thermoplastic Pressure Vessel with Polyamide Matrix

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Solution Overview

Problem

Current pressure vessels, such as type IV tanks with thermoplastic liners and type V tanks with polyamide 12 and carbon fibers, face limitations in structural integrity, acid resistance, and permeation properties, making them unsuitable for stringent safety applications like hydrogen or CNG storage.

Innovation Solution

A pressure vessel with a hollow body comprising endless fibers embedded in a thermoplastic matrix, where the matrix consists of polyamides with a CH2-ratio of at least 5.5 and less than 10, providing improved structural integrity and acid resistance, and suitable for use in hydrogen or CNG vessels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polyamide 12 and carbon fibers are used (type V tank), then structural integrity is improved, but acid resistance and permeation properties deteriorate

Engineering Contradiction:
Improvestructural integrityVSAvoidacid resistance
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent employs a composite material system consisting of carbon fiber reinforcement combined with polyamide 6 or polyamide 6/6 blend matrix. This composite structure achieves both high structural integrity and superior acid resistance by leveraging the complementary properties of the fiber reinforcement and the chemically resistant polyamide matrix.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise compositional parameters for the polyamide matrix, requiring polyamide 6 content to be between 5-50 wt% and polyamide 6/6 content between 50-95 wt%, with additional constraints on CH2-ratio (5.5 ≤ CH2-ratio < 10) and melting point (180-220°C). These parameter controls optimize both structural performance and chemical resistance.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If polyamide 6 is used, then acid resistance is improved, but structural integrity and permeation resistance deteriorate

Engineering Contradiction:
Improveacid resistanceVSAvoidstructural integrity
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent employs a composite material system consisting of carbon fiber reinforcement combined with polyamide 6 or polyamide 6/6 blend matrix. This composite structure achieves both high structural integrity and superior acid resistance by leveraging the complementary properties of the fiber reinforcement and the chemically resistant polyamide matrix.

Inventive Principle:
Principle #40Composite materials

3Weight of moving object

If type IV tanks with thermoplastic liner and thermoset composite are used, then weight is reduced, but recyclability deteriorates and buckling occurs

Engineering Contradiction:
ImproveweightVSAvoidrecyclability
Core Design Contradiction:
Weight of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent transitions from thermoset composites to thermoplastic composite materials, fundamentally changing the material state from cross-linked and irreversible to melt-processable and recyclable. The specified melting point range (180-220°C) enables controlled recycling while maintaining structural performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of using thermoset composites that provide structural integrity but prevent recycling, the patent inverts the approach by using thermoplastic matrices that enable both structural performance and recyclability through their reversible melting and reprocessing characteristics.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3390016A1Pressure vessel
Publication Date: 2018.10.24 ENVALIOR BV

AI summary

This invention relates to a pressure vessel comprising a hollow body comprising endless fibers embedded in a thermoplastic polymer, in which the thermoplastic polymer comprises one or more polyamides containing one or more aliphatic monomeric units, wherein the one or more polyamides have a CH2-ratio of at least 5.5 and less than 10, calculated by  identifying the number of different aliphatic monomeric units in the one or more polyamides;  determining the number of CH2 groups per aliphatic monomeric unit for each of these different aliphatic monomeric units;  calculating the sum of the so determined numbers of CH2 groups;  dividing said sum by the number of different aliphatic monomeric units in the one or more polyamides; taking into account only the aliphatic monomeric units present in the one or more polyamides in an amount of at least 10 wt% with respect to the total weight of the one or more polyamides.