Electromagnetic Wave Suppression Sheet Oxidized Coating High Temperature Swelling
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Solution Overview
Problem
Electromagnetic wave suppression sheets using chlorinated polyethylene as a binder can swell and cause damage when exposed to high temperatures due to a reaction with metal magnetic powder, leading to potential compression of electronic device housings or substrates.
Innovation Solution
An electromagnetic wave suppression sheet is formulated with chlorinated polyethylene, metal magnetic powder having an oxidized coating film, and a phosphorous-based chelating agent, with an oxygen content of 0.4 to 1.1 wt.% in the metal magnetic powder, to inhibit the reaction and maintain magnetic permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chlorinated polyethylene is used as the binder in electromagnetic wave suppression sheet, then flame retardancy and moldability are improved, but the sheet swells and generates gas when used in high temperature environment
Solution Approach 1:
An oxidized coating film is introduced as an intermediary layer between the metal magnetic powder and chlorinated polyethylene binder. This coating film acts as a barrier that prevents direct contact and chemical reaction between the binder and metal powder, thereby eliminating the swelling issue while preserving the flame retardancy and moldability benefits of chlorinated polyethylene
Solution Approach 2:
The invention creates a composite structure where metal magnetic powder particles are coated with an oxidized film, forming a multi-layered composite material. This composite approach allows the system to simultaneously achieve flame retardancy from chlorinated polyethylene, electromagnetic wave suppression from metal powder, and thermal stability from the oxidized coating film
2Stability of the object's composition
If the oxygen content of metal magnetic powder is increased to suppress reaction with chlorinated polyethylene, then swelling is reduced, but magnetic permeability deteriorates
Solution Approach 1:
The invention optimizes the oxygen content parameter of the metal magnetic powder to a specific range (0.4-1.1 wt.%) to achieve the desired balance. By precisely controlling this parameter, the oxidized coating film provides sufficient protection against swelling while maintaining adequate magnetic permeability for effective electromagnetic wave suppression
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 solution prevents swelling and maintains high magnetic permeability, ensuring heat resistance and flexibility of the sheet even in high-temperature environments, effectively suppressing electromagnetic waves.
Implementation Method 1
a metal magnetic powder having an oxidized coating film formed on a surface thereof
Implementation Method 2
from 1 to 15 parts by weight of a phosphorous-based chelating agent
Implementation Method 3
a desired level of magnetic permeability is obtained
Data Source
Figure 1
AI summary
Provided is an electromagnetic wave suppression sheet that is not prone to swelling even when used in a high temperature environment and excels in an electromagnetic wave suppressing effect. The electromagnetic wave suppression sheet contains from 400 to 600 parts by weight of a metal magnetic powder having an oxidized coating film formed on a surface thereof, from 1 to 15 parts by weight of a chelating agent, and from 1 to 10 parts by weight of an anti-aging agent, per 100 parts by weight of chlorinated polyethylene.