Flexible graphite material is non-cellulosic material. Flexible graphite sheet made ​​of molded into the seal packing after use. Flexible graphite, also known as expanded graphite, which is the natural flake graphite impurities removed. And then by strong oxidizing acid mixture treated as graphite oxide. Thermal decomposition of graphite oxide release carbon dioxide, rapid volume expansion, into a loose, soft and have a toughness of flexible graphite. Its characteristics are:
     1 has excellent heat resistance and cold resistance. Flexible graphite ultra-low temperature from -270 degrees to 3650 degrees (in a non-oxidizing gas) heat, the little change in physical properties, can also be used in air to 600 degrees;
     (2) has excellent chemical resistance. In addition to flexible graphite nitric acid, concentrated sulfuric acid and other strong oxidizing corrosive medium, the other acids, alkalis and solvents is almost no corrosion;
     3 have a good self-lubrication. Flexible graphite as with natural graphite, layer the external force, prone to sliding, which has lubricity, better wear reduction, friction coefficient;
     4 rebound rate. When the shaft or sleeve due to manufacturing, installation and there is the emergence of the eccentric radial runout when the float has enough performance, even if the graphite cracks, but also a good seal, thus ensuring post close together to prevent leakage.