| 摘要 |
PROBLEM TO BE SOLVED: To provide a new PTC planar heating element which has both of an excellent PTC property and a low initial electric resistance and has an excellent heating function without causing a partial overheat and has an excellent flexibility and an excellent form stability and has a thin thickness as well. SOLUTION: The PTC planar heating element includes a planar heating sheet made of a PTC electro-conductive composition, composed of carbon black or graphite, paraffine and a thermoplastic elastomer, which is impregnated into or coated on a long textile fabric made of a synthetic fiber and is calcined, and an insulating films are coated on both sides of the sheet and then a heating soaking sheet is coated on one side or both sides of the sheet and moreover the following conditions (1) to (5) are satisfied: (1) A thickness is in a range of 0.6 mm to 1.5 mm, (2) D<SB>20</SB>is in a range of 250 W/m<SP>2</SP>to 600 W/m<SP>2</SP>, (3) D<SB>25</SB>/D<SB>45</SB>is 2 or less, (4) D<SB>45</SB>/D<SB>80</SB>is 10 or more and (5) D<SB>25</SB>/D<SB>80</SB>is 20 or more, wherein D<SB>25</SB>, D<SB>45</SB>, D<SB>80</SB>are power flux densities at 25°C, 45°C and 80°C. COPYRIGHT: (C)2008,JPO&INPIT
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