Copper Foil Composite Resin Layer Sn Coating Formability
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Solution Overview
Problem
Copper foil composites used in flexible printed circuits and electromagnetic shielding materials face issues with severe deformation during press-forming, leading to potential breakage and inadequate corrosion resistance and long-term electric contact stability.
Innovation Solution
A copper foil composite with a resin layer, where the deformation behavior of the resin layer is transmitted to the copper foil, enhancing ductility and preventing cracking, and a surface Sn layer provides corrosion resistance and stable electric contact, with specific stress ratios and adhesion strengths optimized for formability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If press-forming is applied to copper foil composite, then formability and product shape customization are improved, but copper foil breakage occurs due to severe complex deformation
Solution Approach 1:
The invention uses a composite structure of copper foil and resin layer. The resin layer absorbs part of the deformation stress during press-forming, reducing the stress concentration on the copper foil. This allows the copper foil to undergo complex deformation without breaking, thereby improving formability while maintaining copper foil integrity.
Solution Approach 2:
The invention optimizes the thickness ratio between the resin layer and copper foil, and controls the stress distribution through specific dimensional parameters. By adjusting these parameters, the deformation behavior is controlled to prevent copper foil breakage during press-forming while achieving the desired formability.
2Ease of operation
If copper foil is made thinner to improve flexibility, then bending properties are improved, but corrosion resistance and electric contact stability deteriorate
Solution Approach 1:
The invention combines thin copper foil with a resin layer to create a composite structure. The resin layer provides protective functions including corrosion resistance, while the thin copper foil maintains flexibility. This composite approach allows the copper foil to be thin without sacrificing corrosion resistance or electric contact stability.
Solution Approach 2:
The resin layer acts as an intermediary between the copper foil and the corrosive environment. It protects the copper foil from direct exposure to corrosive substances while maintaining the electrical conductivity and flexibility of the thin copper foil layer.
Data Source
Figure 1~2
AI summary
A copper foil composite comprising a copper foil and a resin layer laminated thereon, satisfying an equation 1: (f3 x t3)/(f2 x t2) => 1 wherein t2 (mm) is a thickness of the copper foil, f2 (MPa) is a stress of the copper foil under tensile strain of 4%, t3 (mm) is a thickness of the resin layer, f3 (MPa) is a stress of the resin layer under tensile strain of 4%, and an equation 2:1 <= 33f1/(F x T) wherein f1 (N/mm) is 180° peeling strength between the copper foil and the resin layer, F(MPa) is strength of the copper foil composite under tensile strain of 30%, and T (mm) is a thickness of the copper foil composite, wherein a Sn layer having a thickness of 0.2 to 3.0 µm is formed on a surface of the copper foil on which the resin layer is not laminated.