To enhance the strength of a building material and to achieve advantageous application of an electromagnetic wave shielding layer by allowing a core member constituting a composite building material having the shielding layer formed at least on one surface thereof to contain an inorganic amorphous body internally having fibrous materials.
A core member 3 containing an inorganic amorphous body 1 and fibrous materials 2 mixed therein, has reinforcing layers 5 on front and rear surfaces thereof, and an electromagnetic wave shielding layer 4 is arranged on the reinforcing layer 5. The inorganic amorphous body 1 is an amorphous compound obtained by solution treatment or hydration of at least two oxides. In the core member 3, the inorganic amorphous body 1 serves as a strength manifestation material and the fibrous materials 2 are dispersed in the inorganic amorphous body 1 to improve a fracture toughness value, whereby a bending strength value and impact resistance can be improved. Further, since the core member 3 is of the amorphous body, sufficient strength can be obtained in low density. Therefore, the shielding layer 4 can be prevented from being broken due to an impact, whereby the composite building material is rendered applicable to a wall member and a floor member of a room in which office automation equipment is set or of an intensive care unit in a hospital.
OGAWA TETSUJI
SATO KENJI
NOMURA TOSHIHIRO
