Copper Foil Composite Resin Layer Flexibility

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Solution Overview

Problem

Copper foil composites used for electromagnetic shielding and flexible printed circuits face challenges with flexibility and workability, as thicker foils are stiff and difficult to bend, while thinner foils are brittle and prone to cracking, making them unsuitable for applications requiring both flexibility and durability.

Innovation Solution

A copper foil composite with a resin layer, where the elongation after fracture is 5% or more and the ratio of resin layer stress to copper foil stress under tensile strain is greater than or equal to 1, ensuring enhanced workability and flexibility, with specific thickness and composition optimizations for electromagnetic shielding and flexible printed circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the thickness of copper foil is increased, then elongation and ductility are improved, but stiffness increases making the shielding process difficult

Engineering Contradiction:
ImproveelongationVSAvoidshielding process workability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent uses a composite structure consisting of copper foil laminated with a resin layer. The resin layer acts as a matrix that binds the copper foil, allowing the composite to achieve both flexibility and strength. This composite approach enables the material to be thin enough for easy shielding processes while maintaining sufficient elongation properties through the copper component.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs thin film technology by using copper foil with controlled thickness (3-10 μm) laminated with a resin layer. This thin film composite structure provides the necessary flexibility for shielding operations while the laminated resin layer prevents cracking and maintains structural integrity during bending and forming operations.

Inventive Principle:
Principle #30Flexible shells and thin films

2Ease of operation

If the thickness of copper foil is decreased, then flexibility is improved, but ductility significantly decreases causing the foil to be easily broken or cracked

Engineering Contradiction:
ImproveflexibilityVSAvoidductility
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent creates a composite material where thin copper foil (3-10 μm) is laminated with a resin layer having specific mechanical properties. The resin layer compensates for the low ductility of thin copper foil by providing structural support and crack resistance, while the copper layer maintains flexibility and electrical conductivity for shielding purposes.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The resin layer serves as an intermediary between the thin copper foil and the external environment. It protects the brittle thin copper foil from mechanical damage during handling and installation, while allowing the copper to maintain its flexibility and electromagnetic shielding properties. The resin acts as a protective matrix that enables the thin foil to be used in flexible applications.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If thicker copper foil is used, then electromagnetic shielding properties are ensured, but the shielding process becomes difficult due to increased stiffness

Engineering Contradiction:
Improveelectromagnetic shielding propertiesVSAvoidshielding process difficulty
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent uses a composite of copper foil and resin layer where the copper provides electromagnetic shielding properties and the resin provides flexibility. This composite structure achieves effective shielding with thinner materials that are easier to handle and install compared to thicker solid copper foils, while maintaining the necessary electromagnetic protection.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent implements flexible thin film shielding by laminating copper foil (3-10 μm) with a resin layer. This thin film composite provides effective electromagnetic shielding while remaining flexible enough for easy installation around cables and other structures, eliminating the handling difficulties associated with thicker stiff copper foils.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP2439063B1Copper foil composite
Publication Date: 2015.02.25 JX NIPPON MINING & METALS CORP

AI summary

A copper foil composite comprising a copper foil and a resin layer laminated thereon, wherein elongation after fracture of the copper foil is 5% or more, and wherein (F x T)/(f x t) => 1 is satisfied when t is a thickness of the copper foil, f is a stress of the copper foil under tensile strain of 4%, T is a thickness of the resin layer and F is a stress of the resin layer under tensile strain of 4%.