Thermoplastic Elastomer Overmolding Polyamide Adhesion

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Solution Overview

Problem

Nylon tool handles lack adequate cushioning against impact and vibration, and existing overmold layers do not provide sufficient adhesion or oil resistance.

Innovation Solution

A thermoplastic elastomer composition comprising a thermoplastic vulcanizate, an olefinic block copolymer, and a functionalized polyolefin copolymer is used for overmolding polyamide substrates, enhancing adhesion and providing improved oil resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a thermoplastic elastomer layer is overmolded on a polyamide substrate, then cushioning against impact and vibration is improved, but adhesion between the layers is insufficient

Engineering Contradiction:
Improvecushioning against impact and vibrationVSAvoidadhesion between layers
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the thermoplastic elastomer by incorporating specific functional groups (carboxylic acid, hydroxyl, amine, or isocyanate groups) that can chemically interact with polyamide surfaces. This parameter change in molecular structure enables strong adhesion while preserving the cushioning properties of the elastomer material.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining thermoplastic elastomer base polymers with functional additives containing reactive groups. This composite approach integrates the cushioning characteristics of the elastomer with the adhesion capabilities of the functional groups, resolving the contradiction between softness and bonding strength.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If existing overmold layers are applied to polyamide substrates, then the soft feel is achieved, but oil resistance is insufficient

Engineering Contradiction:
Improvesoft feelVSAvoidoil resistance
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical composition by incorporating functional groups that provide oil resistance while maintaining the elastomeric softness. The functionalized polyolefin copolymer with specific reactive groups creates a material that resists oil degradation while preserving the desired tactile properties.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If adhesive is used to bond the overmold layer to the polyamide substrate, then adhesion is improved, but device complexity and manufacturing steps increase

Engineering Contradiction:
ImproveadhesionVSAvoidmanufacturing steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the adhesive function into the thermoplastic elastomer material itself by incorporating functional groups that provide bonding capability. This eliminates the need for separate adhesive layers or additional bonding steps, reducing manufacturing complexity while maintaining strong adhesion.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The thermoplastic elastomer composition is designed to perform multiple functions simultaneously: providing cushioning, ensuring adhesion through functional groups, and offering oil resistance. This multi-functional material eliminates the need for separate adhesive components and simplifies the overall manufacturing process.

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 solution provides superior adhesion, oil resistance, and a soft feel to nylon tool handles without the need for adhesives, improving their gripping and deformation properties.

Implementation Method 1

superior adhesion, oil resistance, and a soft feel to nylon tool handles without the need for adhesives

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS12084568B2Thermoplastic elastomer composition for overmolding polyamides
Publication Date: 2024.09.10 HEXPOL TPE AMERICAS LLC

AI summary

A thermoplastic elastomer composition for overmolding a predominantly polyamide substrate, a method for the preparation of an overmolded article, and an overmolded article having a layer of thermoplastic elastomer is provided. The thermoplastic elastomer composition comprises a thermoplastic vulcanizate, an olefinic block copolymer, and a maleated functionalized polyolefin copolymer. The method for the preparation of the overmolded article comprises heating the thermoplastic elastomer composition followed by applying the heated composition to at least a portion of the predominantly polyamide substrate.