CNT Multilayer Shielding Sheet for Thin, Handleable EM Protection
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Solution Overview
Problem
Existing electromagnetic (EM) shielding materials using carbon nanotubes (CNTs) face challenges in achieving sufficient conductivity and thickness, making them unsuitable for miniaturized electronic devices and difficult to handle.
Innovation Solution
An EM-shielding sheet comprising a multilayer film of carbon nanotube nonwoven fabric with a resistivity of 0.00005 to 0.05 Ω·cm and a thickness of 1 to 500 μm, including a resin layer and a release film, which can be laminated with an adhesive layer for easy application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotube sheets are used for EM shielding, then EM-shielding performance is improved, but the thickness must be increased to achieve equivalent performance to metal foils
Solution Approach 1:
The patent combines carbon nanotubes with ferromagnetic ingredients (iron or cobalt) to create a composite material that exhibits both high EM-shielding performance and sufficient conductivity. This composite structure allows the material to achieve metal-equivalent shielding effectiveness without increasing thickness, as the ferromagnetic components enhance the intrinsic shielding capability of the CNT network.
Solution Approach 2:
The patent modifies the electrical and magnetic parameters of the CNT sheet by adding ferromagnetic ingredients and controlling the protonation state. By adjusting these parameters, the material achieves optimal balance between conductivity and EM-shielding performance, enabling thin-film applications without sacrificing shielding effectiveness.
2Reliability
If carbon nanotubes are added to increase conductivity, then EM-shielding performance is improved, but the materials become awkward to handle
Solution Approach 1:
The patent creates a flexible thin film structure where CNTs are dispersed within a resin matrix. This formulation provides both the desired electrical conductivity and mechanical flexibility, making the material easy to handle and apply to various surfaces while maintaining high EM-shielding performance.
Solution Approach 2:
The patent uses resin as an intermediary material to bind the CNTs together, forming a cohesive and handleable sheet structure. The resin matrix provides mechanical integrity while allowing the CNT network to maintain its conductive pathways, solving the handling difficulty of pure CNT materials.
3Reliability
If fine fibril form CNTs are used, then EM-shielding performance is improved, but the CNTs cannot be dispersed in large amounts due to large specific surface area
Solution Approach 1:
The patent employs resin as a dispersing medium and binding agent that enables high concentrations of fine CNTs to be uniformly distributed throughout the material. The resin prevents CNT aggregation while maintaining their fine fibril structure, allowing maximum EM-shielding performance without processing difficulties.
Solution Approach 2:
By creating a composite system where CNTs are embedded in a resin matrix, the patent achieves uniform dispersion of large amounts of fine CNTs. The composite structure leverages the complementary properties of both materials: the high surface-area CNTs provide EM-shielding while the resin provides processability and structural integrity.
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 multilayer structure provides equivalent EM-shielding performance with reduced thickness, enhancing conductivity and ease of handling, suitable for covering electronic parts and connections in electronic equipment.
Implementation Method 1
an electromagnetic wave-shielding sheet adapted to cover electronic parts or wirings within electronic instruments for shielding them from electromagnetic waves
Implementation Method 2
an adhesive layer disposed on one outermost surface of the multilayer film
Data Source
AI summary
An electromagnetic-shielding sheet (1a, 1b or 1c) is provided comprising a multilayer film including at least two layers (2) of carbon nanotube nonwoven fabric, an adhesive layer (5), and a release film (6). The sheet exerts the electromagnetic-shielding effect while minimizing the thickness of carbon nanotube nonwoven fabric, is easy to handle, and is used to cover electronic parts and connections within electronic equipment.