Polyamide Overmolding on Nano-Textured Metal Substrates

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Solution Overview

Problem

Current nano-molding technology for plastic-metal hybrid parts faces limitations in achieving high bonding strength and is primarily restricted to specific materials, hindering the widespread application and integration of functions in miniaturized and automated assemblies.

Innovation Solution

A process involving a metal substrate with nano-size surface irregularities, overmolded with a polyamide composition comprising a blend of semi-crystalline and amorphous semi-aromatic polyamides, enhancing bonding strength through suitable pretreatment methods and optional annealing steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional nano-molding technology with T-treatment or anodizing is used, then bonding strength is improved, but material compatibility is limited to specific materials only

Engineering Contradiction:
Improvebonding strengthVSAvoidmaterial compatibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The invention changes the chemical composition parameters of the polyamide material by incorporating aromatic diamine units (specifically meta-xylylenediamine or p-xylylenediamine) into the polymer structure. This compositional parameter change enables the material to achieve high bonding strength across multiple metal substrates (aluminum, stainless steel, titanium) rather than being limited to single-material applications

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite polyamide material that combines semi-aromatic polyamide base structures with specific aromatic diamine units. This composite approach integrates the thermal stability of semi-aromatic polyamides with the enhanced adhesion properties of aromatic diamines, resulting in a material that simultaneously achieves high bonding strength and broad material compatibility

Inventive Principle:
Principle #40Composite materials

2Strength

If multi-stage pretreatment processes are applied, then bonding strength is improved, but process complexity increases

Engineering Contradiction:
Improvebonding strengthVSAvoidprocess complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention performs preliminary chemical modification during the polymer synthesis stage by incorporating aromatic diamine units into the polyamide structure before the actual bonding process. This preliminary action embeds adhesion-promoting functional groups within the material itself, eliminating the need for complex multi-stage surface pretreatment processes

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The polyamide material with aromatic diamine units possesses inherent adhesion-promoting properties that enable it to self-bond effectively to metal surfaces without requiring external pretreatment agents or complex surface preparation steps. The material essentially serves its own surface preparation function through its molecular structure

Inventive Principle:
Principle #25Self-service

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 process significantly increases bonding force between metal and plastic parts, exceeding previous systems, and allows for broader material compatibility, enhancing the versatility and performance of plastic-metal hybrid parts.

Implementation Method 1

a metal substrate having a surface area with surface irregularities of nano-size dimensions

Methodology Applied
Scientific EffectNano-molding:

Implementation Method 2

forming a plastic structure on the metal substrate by molding said polyamide composition directly on at least a part of the surface area

Methodology Applied
Scientific EffectOvermolding:

Implementation Method 3

the bonding strength at the metal-plastic interface results from or is enhanced by a pretreatment of the metal

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3389976B1Process for plastic overmolding on a metal surface and plastic-metal hybrid part
Publication Date: 2021.07.14 DSM IP ASSETS BV
  • EP3389976B1 patent drawingFigure 1A~1B

AI summary

The invention relates to a process for manufacturing a plastic-metal hybrid part by plastic overmolding on a metal surface via nano-molding technology (NMT), wherein the moldable plastic material is a polyamide composition comprising a blend of a semi-crystalline semi-aromatic polyamide and an amorphous semi-aromatic polyamide. The invention also relates to Plastic-metal hybrid part, obtainable by siaid process, wherein a metal part is overmolded by a polyamide composition comprising a blend of a semi-crystalline semi-aromatic polyamide and an amorphous semi-aromatic polyamide.