Polyamide Composite Structures Resolving Adhesion and Durability

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Solution Overview

Problem

Conventional thermoplastic polyamide resin compositions used for impregnating and overmolding fibrous layers in composite structures often require excessive heating, leading to poor adhesion and mechanical properties, which can result in cracks, delamination, and reduced durability in demanding applications like automotive and aerospace.

Innovation Solution

A composite structure with a surface resin composition and matrix resin composition made from blends of fully aliphatic polyamides with melting points above 250°C, such as poly(tetramethylene hexanediamide) (PA46) and poly(hexamethylene hexanediamide) (PA66), which provides improved impact resistance and flexural strength, and enhances adhesion with overmolding resins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional thermoplastic polyamide resin compositions are used for impregnating and overmolding fibrous layers, then the composite structure can be manufactured, but excessive heating is required which leads to poor adhesion and reduced mechanical properties

Engineering Contradiction:

Improvemanufacturability of composite structureVSAvoidadhesion quality and mechanical properties

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the chemical composition parameters of the polyamide resin, specifically incorporating polyamides with melting points of at least 250°C and using blends of different polyamides in controlled ratios. This changes the thermal and rheological parameters of the resin system, enabling proper adhesion and mechanical properties without excessive heating, thus resolving the contradiction between ease of manufacture and reliability.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional polyamide resin compositions are used, then the composite structure can be formed, but cracks and delamination occur at the interface reducing durability

Engineering Contradiction:

Improveformability of composite structureVSAvoidinterface strength and durability

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent employs composite materials by creating a multi-component polyamide resin system that combines different polyamides (including those with melting points ≥250°C) in specific ratios. This composite resin formulation provides both the formability needed for composite structure manufacturing and the enhanced interface strength that prevents cracks and delamination, thereby resolving the contradiction between ease of manufacture and strength.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If excessive heating is applied during stamping, forming, or shaping, then the composite structure can be formed, but the surface appearance and functionality deteriorate

Engineering Contradiction:

Improveprocessability during formingVSAvoidsurface quality and functionality

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent uses parameter changes by selecting polyamides with specific melting point parameters (at least 250°C) and controlling the resin blend composition. These parameter changes allow the composite structure to be formed at reduced temperatures, maintaining surface appearance and functionality while still achieving proper forming, thus resolving the contradiction between ease of manufacture and surface quality.

Inventive Principle:

Principle #35Parameter changes

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 described composite structure exhibits superior flexural strength and adhesion, resisting deterioration and delamination, thus improving the mechanical performance and durability of composite structures under various conditions.

Implementation Method 1

conventional thermoplastic polyamide resin compositions that are used to impregnate one or more fibrous layers and to overmold the one or more impregnated fibrous layers may require excessive heating during stamping, forming, or shaping

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

a surface resin composition selected from polyamide compositions comprising a blend of two or more fully aliphatic polyamides having a melting point of at least 250°C and wherein the matrix resin composition is selected from polyamide compositions comprising a one or more fully aliphatic polyamides having a melting point of at least 250°C

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentEP2632709B1Polyamide composite structures and processes for their preparation

Publication Date: 2019.11.20 EI DU PONT DE NEMOURS & CO

AI summary

The present invention relates to the field of composite structures and processes for their preparation, particularly it relates to the field of polyamide composite structures. The disclosed composite structures comprise a surface, which surface has at least a portion made of a surface resin composition, and comprise a fibrous material selected from non-woven structures, textiles, fibrous battings and combinations thereof, said fibrous material being impregnated with a matrix resin composition, wherein the surface resin composition is selected from polyamide compositions comprising a blend of two or more fully aliphatic polyamides having a melting point of at least 250°C and wherein the matrix resin composition is selected from polyamide compositions comprising a one or more fully aliphatic polyamides having a melting point of at least 250°C.