Lg Cable Ltd.

Soo-An Choi

Jong-Ho Lee

Tae-Sung Kim

Do-Yun Kim

Chang-Hee Choi

Chang-Mo Ko

Joon-Koo Han

Jun-Ku Hahn

PTC conductive polymer composition includes organic polymer containing polyolefin components essentially consisting of 30&#x2dc;40 w % high density polyethylene (HDPE), 20&#x2dc;40 w % low density polyethylene (LDPE) and 10&#x2dc;30 w % ethylene-acrylic-acid (EAA) or ethylene-vinyl-acetate (EVA), and 20&#x2dc;30 w % high or low density polyethylene which is denaturated into maleic anhydride compound; 60&#x2dc;120 w % electrical conductive particles dispersed into the organic polymer, the electrical conductive particles by weight of the organic polymer; and 0.2&#x2dc;0.5 w % peroxidic cross-linking agent added for cross-linking reaction by weight of the organic polymer. Thus, it becomes possible to control PTC characteristics such as switching temperature and trip time of an electrical device by suitably adjusting an added amount of the polyethylene, which is denaturated into maleic anhydride compound.

Conductive polymer having positive temperature coefficient, method of controlling positive temperature coefficient property of the same and electrical device using the same

An electrical device including a PTC conductive polymer sheet, and first and second electrodes physically contacted with opposite surfaces of the conductive polymer sheet is disclosed. The first and second electrodes have a plurality of protrusions protruded from surfaces thereof, respectively. The protrusions have an surface roughness (Rz) of 1 to 20 &#x3bc;m and an average width ({overscore (Rw)}) which is 0.5 to 2 times of the surface roughness (Rz), and an average gap ({overscore (Rg)}) between adjacent protrusions is 0.5 and 2 times of the surface roughness (Rz). The conductive polymer sheet has a thickness which is more than 5 times of the surface roughness (Rz).

Electrical device having PTC conductive polymer

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Kyunggi-do, South Korea

Soo-An Choi