Thermoplastic Elastomer Adhesion to Polyamide via Maleated SEBS

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Solution Overview

Problem

Thermoplastic elastomers (TPEs) face challenges in adhering to polyamide-containing compounds, which is crucial for forming effective two-part component extruded or molded parts, especially in applications like automobile door seals where polyamide is used for its rigid structure.

Innovation Solution

A thermoplastic elastomer compound is formulated using high molecular weight maleated styrene-ethylene-butylene-styrene (HMW MAH-g-SEBS) as a compatibilizer, combined with a plasticizer, processing aid, and polyamide, enhancing adhesion to polyamide-containing components and improving performance at elevated temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional thermoplastic elastomers are used, then processing properties are good, but adhesion to polyamide is poor

Engineering Contradiction:
Improveadhesion to polyamideVSAvoidprocessing difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent introduces a polyamide component as an intermediary substance within the TPE formulation. This polyamide acts as a chemical bridge that facilitates adhesion between the TPE matrix and external polyamide substrates. The maleated styrene-ethylene-butylene-styrene copolymer serves as another intermediary, with its maleic anhydride groups forming chemical bonds with polyamide surfaces, thereby resolving the adhesion problem while maintaining processing ease

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite TPE material by combining multiple components: styrene-ethylene-butylene-styrene copolymer, polyamide, plasticizer, and processing aid. This composite formulation integrates the beneficial properties of each component - the copolymer provides elastomeric properties, the polyamide component provides adhesion to polyamide substrates, the plasticizer provides flexibility, and the processing aid ensures ease of manufacturing. This composite approach resolves the contradiction between adhesion strength and processing ease

Inventive Principle:
Principle #40Composite materials

2Reliability

If low molecular weight maleated SEBS is used as compatibilizer, then processing is easier, but compression set at elevated temperatures is poor

Engineering Contradiction:
Improvecompression set resistance at elevated temperaturesVSAvoidprocessing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by transitioning from low molecular weight maleated SEBS to high molecular weight maleated SEBS. This molecular weight parameter change fundamentally alters the material's thermal stability and compression set resistance. The higher molecular weight provides better entanglement and structural integrity at elevated temperatures, significantly improving compression set resistance while the maleated groups maintain compatibility and processability

Inventive Principle:
Principle #35Parameter changes

3Strength

If polyamide is added to TPE formulation, then adhesion to polyamide improves, but formulation complexity increases

Engineering Contradiction:
Improveadhesion to polyamideVSAvoidformulation complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The polyamide component in the formulation serves multiple functions simultaneously: it acts as a compatibilizer to improve adhesion to polyamide substrates, it serves as a secondary polymer matrix component, and it provides chemical bonding sites through its amine groups. This multi-functionality reduces the need for separate adhesion promoters or coupling agents, thereby limiting the increase in formulation complexity while achieving excellent adhesion

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 new formulation achieves excellent adhesion to polyamides, significantly reducing compression set at elevated temperatures, ensuring a better seal and performance in industrial and consumer products, such as automobile door seals and other applications.

Implementation Method 1

A thermoplastic elastomer compound providing adhesion to polyamide-containing compounds

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS8193273B2Thermoplastic elastomers for adhesion to polyamide
Publication Date: 2012.06.05 AVIENT CORP

AI summary

A thermoplastic elastomer (TPE) is disclosed which has excellent compression set and adhesion to both polyamide 6 and polyamide 6,6 for use in two-part component polymer structures.