Metal Foil Composite Bending Properties

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Solution Overview

Problem

Current metal foil composites used for electromagnetic shielding and flexible printed circuits lack severe bending properties, particularly in 180-degree intimate bending, which is necessary for mounting in compact mobile devices and forming heat sinks, and have limited press formability.

Innovation Solution

A metal foil composite is developed with a resin layer and a metal foil laminated on one or both surfaces via an adhesion layer, where the elastic modulus of the total layer, including the adhesion layer and resin layer, is 80% to 100% of the resin layer's modulus, and specific thickness and stress relationships are maintained to enhance bending properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the copper foil thickness is increased to ensure electromagnetic shielding properties, then the shielding effectiveness is improved, but the bending properties and formability deteriorate

Engineering Contradiction:
Improveelectromagnetic shielding effectivenessVSAvoidbending properties and formability
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent uses a composite structure consisting of a metal foil layer (for electromagnetic shielding) and a resin film layer (for flexibility and formability). This composite material combines the advantages of both materials: the metal foil provides shielding effectiveness while the resin film enables severe bending and forming without cracking, thus resolving the contradiction between shielding performance and bending properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs a thin resin film laminated on the metal foil to provide flexibility and enable severe bending. The resin film acts as a flexible shell that allows the rigid metal foil to undergo 180-degree intimate bending and complex forming operations without damage, thereby improving bending properties while maintaining shielding effectiveness.

Inventive Principle:
Principle #30Flexible shells and thin films

2Manufacturing precision

If the resin film thickness is increased to improve elongation and formability, then the bending properties are improved, but the electromagnetic shielding effectiveness deteriorates

Engineering Contradiction:
Improveelongation and formabilityVSAvoidelectromagnetic shielding effectiveness
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the thickness parameters of both the metal foil and resin film to achieve a balance. By carefully controlling the thickness of each layer, the patent ensures that the resin film provides sufficient elongation and formability while the metal foil maintains adequate electromagnetic shielding effectiveness, thus resolving the contradiction between these two properties.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the adhesion layer is optimized to improve bonding strength, then the interlayer adhesion is improved, but the bending properties may deteriorate due to rigid interface

Engineering Contradiction:
Improveinterlayer adhesion strengthVSAvoidbending properties
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent optimizes the thickness and material properties of the adhesion layer to achieve a balance between bonding strength and bending flexibility. By controlling the adhesion layer parameters, the patent ensures sufficient interlayer adhesion while maintaining the ability to undergo severe bending without delamination or cracking.

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 composite exhibits improved bending properties and formability, allowing for repeated 180-degree bending and press forming, making it suitable for compact device integration and heat dissipation applications.

Implementation Method 1

a resin layer and a metal foil via an adhesion layer laminated on one or both surfaces of the resin layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2679384B1Metallic foil composite, flexible printed circuit board using same, molded body, and manufacturing method for molded body
Publication Date: 2015.05.13 JX NIPPON MINING & METALS CORP
  • EP2679384B1 patent drawingFigure 1(a)~1(d)
  • EP2679384B1 patent drawingFigure 2~3

AI summary

A metal foil composite 10 comprising a resin layer 6 and a metal foil 2 laminated on one or both surfaces of the resin layer via a adhesion layer 4, wherein elastic modulus of a total layer including the adhesion layer and the resin layer is 80% to 100% of the elastic modulus of the resin layer.