Electromagnetic wave shield sheet manufacturing method and electromagnetic wave shield sheet
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Solution Overview
Problem
Carbon nanotubes are expensive, making electromagnetic wave shielding sheets costly; replacing a portion with inorganic pigments while maintaining shielding properties is necessary.
Innovation Solution
A method involving the preparation of a dispersion with carbon nanotubes, inorganic pigments, and sodium carboxymethyl cellulose, with specific mass ratios and dispersing techniques to create an electromagnetic wave shielding sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotubes are used to produce electromagnetic wave shielding sheets, then shielding property is improved, but cost increases
Solution Approach 1:
The patent uses composite materials by combining carbon nanotubes with inorganic pigments (such as titanium dioxide, zinc oxide, or silicon oxide) to create a hybrid shielding sheet. This composite approach allows the expensive carbon nanotubes to work synergistically with cheaper inorganic materials, maintaining high shielding effectiveness while reducing overall material cost. The inorganic pigments contribute to electromagnetic wave reflection and absorption, complementing the carbon nanotube network's shielding mechanism.
Solution Approach 2:
The patent replaces a portion of the expensive carbon nanotubes with cheaper inorganic pigment particles. By using only 1-10 mass% carbon nanotubes and 90-90 mass% inorganic pigments, the invention substitutes high-cost materials with low-cost alternatives while maintaining functional performance through the synergistic effect of the composite structure.
2Ease of manufacture
If inorganic pigment replaces carbon nanotubes, then cost decreases, but shielding property deteriorates
Solution Approach 1:
The patent optimizes the concentration parameters of carbon nanotubes (1-10 mass%) and inorganic pigments (90-90 mass%) to achieve the desired shielding performance at reduced cost. By carefully controlling these compositional parameters and the dispersion process, the invention maintains effective electromagnetic wave shielding while using minimal amounts of expensive carbon nanotubes.
Solution Approach 2:
The patent uses dispersants (such as surfactants or polymer dispersants) as intermediary substances to ensure uniform distribution of both carbon nanotubes and inorganic pigments in the coating composition. This proper dispersion prevents aggregation and ensures that the carbon nanotubes form an effective shielding network even at low concentrations, while the inorganic pigments are evenly distributed to provide additional shielding contribution.
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
Produces a cost-effective electromagnetic wave shielding sheet with high shielding properties using a combination of carbon nanotubes and inorganic pigments.
Implementation Method 1
a sheet for shielding an electromagnetic wave is produced from a carbon nanotube aqueous dispersion
Implementation Method 2
the inorganic pigment having a specific gravity of 2.0 or more
Implementation Method 3
using, as dispersants, a polysaccharide formed of carboxymethyl cellulose or the like and an anionic surfactant
Data Source
AI summary
A method of producing an electromagnetic wave shielding sheet by which an electromagnetic wave shielding sheet having a high shielding property against an electromagnetic wave and having low cost is produced. The method of producing an electromagnetic wave shielding sheet includes; preparing a dispersion containing carbon nanotubes, an inorganic pigment, sodium carboxymethyl cellulose, and water; and drying the dispersion. In the dispersion, a ratio of a mass of the inorganic pigment to a mass of the carbon nanotubes is 1/4 or more and 1 or less.