| 摘要 |
PROBLEM TO BE SOLVED: To realize an electromagnetic shielding material which is a few mm thick and capable of effectively shielding a target equipment from electromagnetic waves by a method in which the electromagnetic shielding material is formed of plastic or polyurethane molded body which contains burned acicular iron powder. SOLUTION: Needle crystal of FeOOH (goethite) is heated in an atmosphere of hydrogen to be reduced by hydrogen so as to turn into 0.2μm long and 0.02μm wide acicular iron powder, and the acicular iron powder is burned in a vacuum and ground. Then, 100 pts.wt. of burned acicular iron powder and 100 pts.wt. of polypropylene resin are mixed together and molded into a 2mm thick plastic board. When the plastic board 2 is brought into close contact with the case of a portable telephone, the portable telephone is electromagnetically shielded well. Therefore, an electromagnetic shielding material which is a few mm in thickness and capable of effectively shielding a target equipment from electromagnetic waves can be formed.
|
