| 摘要 |
PURPOSE:To obtain an electromagnetic wave shielding sheet with a desired thickness, by stretching a laminate comprising a sheet of a thermoplastic resin A containing an electroconductive powder such as a metal powder and a sheet of a thermoplastic resin B containing a finely divided inorganic powder and having a melting point higher than that of the resin A by a specified degree at a temperature higher than the melting point of the resin A and lower than the melting point of the resin B to produce a laminated and stretched sheet having a number of fine voids in the sheet of the thermoplastic resin B. CONSTITUTION:As an electroconductive powder is used powder of gold, silver, copper or the like having a particle diameter of 60mu or below in a proportion of 5-50wt% of the sheet material. As a resin A for a sheet use is made of an ethylene/propylene copolymer, etc. As an inorganic finely divided powder use is made of calcium carbonate or the like in a proportion of 8-65wt% of the sheet. As a resin B use is made of a polypropylene, polyamide, or the like, and the resin B for a synthetic paper is a thermoplastic resin having a melting point higher than that of the resin A constituting conductive sheet layers by 15 deg.C or more. |
