| 摘要 |
PROBLEM TO BE SOLVED: To provide an earth material which can secure a low earthing resistance without being buried deeply in the ground. SOLUTION: The earth material 15 is constituted by laminating a copper sheet 11 of 20 to 50μm in thickness and a nonwoven fabric 12 of 100 to 400 g/m<SP>2</SP>in basis weight with an adhesive 13. Since the copper sheet and the nonwoven fabric deform plastically, when the ground surface where the earth material is buried is leveled, the earth material 15 is pressed and deformed by earth and sand 18, increasing an effective contact area with the earth 17 and securing a low earthing resistance. The nonwoven fabric to be used is a needle punching felt in which a fibrous web composed of staple fibers of crimped synthetic fibers of 1 to 15 dtex in single fiber fineness is subjected to needle punching to entangle and fluffing the fibers. The copper sheet is preferably with irregular fine wrinkles 16. The earth material is folded with the nonwoven fabric inside, or two sheets of the earth material may be superposed with the nonwoven fabrics inside to make a double structure, further decreasing the earthing resistance. The earth material can serve simultaneously as a grass-proofing sheet. COPYRIGHT: (C)2009,JPO&INPIT
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