摘要 |
<p>Carbon blacks having a carbon content greater than 99%, a mean particle diameter of 250 to 300 A, an electrical resistivity, measured under a pressure of 6.3 bars, of 0.270 to 0.350 ohm.cm and a DBP index of 400 to 500 ml per 100 g of black are disclosed together with a process for their preparation by incomplete combustion of acetylene in air. These blacks may be used especially for the manufacture of electric cells.</p> |