US 7,544,427 B2
Woody electric-wave-absorbing building material
Hideo Oka, Morioka (Japan)
Assigned to Incorporated National University Iwate University, Morioka-shi (Japan)
Appl. No. 10/586,471
PCT Filed Dec. 20, 2004, PCT No. PCT/JP2004/018998
§ 371(c)(1), (2), (4) Date Jul. 18, 2006,
PCT Pub. No. WO2005/069712, PCT Pub. Date Jul. 28, 2005.
Claims priority of application No. 2004-011249 (JP), filed on Jan. 19, 2004.
Prior Publication US 2007/0164893 A1, Jul. 19, 2007
Int. Cl. G11B 23/00 (2006.01)
U.S. Cl. 428—692  [428/355 R; 428/537.1] 3 Claims
 
1. A woody electric-wave-absorbing building material comprising:
two or more woody plates composed of natural wood or a processed woody material;
a magnetic layer composed of an adhesive containing a ferrite powder interposed between two of the woody plates, wherein
the magnetic layer contains a nonmagnetic austenite stainless steel powder in an amount in the range of 30 to 50 volume percent relative to a Mn—Zn ferrite powder,
the total volume content of the ferrite powder and the nonmagnetic austenite stainless steel powder in the magnetic layer is in the range of 10% to 40%,
the thickness of the magnetic layer is in the range of 1.0 to 4.0 mm, and
the electric-wave-absorbing building material has an electric wave absorption characteristic in which the center frequency of the electric waves absorbed lies in the range of1 to 8 GHz and the amount of electric wave absorption is 20 dB or more in a 2.45 GHz frequency band.