Compositions for electromagnetic wave absorption and methods for manufacturing thereof

Abstract

This invention relates to an electromagnetic wave absorbing composition, characterized by comprising: (A) an electromagnetic wave absorbing filler, which accounts for 6% to 30% by mass relative to the total composition of the electromagnetic wave absorbing composition; and (B) an organic resin, which accounts for 70% to 94% by mass relative to the total composition of the electromagnetic wave absorbing composition; wherein the slope of the straight line obtained by linear fitting of the aforementioned (A) electromagnetic wave absorbing filler with relative permittivity as the X-axis and dielectric loss tangent as the Y-axis is 0.050 or higher, and the relative permittivity and dielectric loss tangent are measured values ​​obtained by means of: in a selected composition of filler with different amounts of three or more selected fillers mixed with the aforementioned (B) organic resin and the selected composition of filler formed into a sheet-like hardened material, the dielectric loss tangent and relative permittivity at 60 GHz to 90 GHz are measured by free space method using a vector network analyzer. This provides a component for electromagnetic wave absorption that exhibits a low relative permittivity and a high dielectric loss tangent, and demonstrates excellent absorption characteristics in the high-frequency band of 60 GHz to 90 GHz. none