| 摘要 |
Antistatic properties are imparted to plastics by blending a pulverulent plastics material and, if desired further addends, with conductive carbon black and making the resulting blend into a moulding composition. The plastics are more particularly blended with 4 to 12 weight % of conductive carbon black having a water absorption stiffness (AS-number) of 15 to 35, a specific electric resistance of 10-1 up to 10-3 ohms . cm under a moulding pressure of 100 to 180 atmospheres absolute, a bulk density of 100 to 180 g/liter, a BET-surface area of 100 to 1000 m2/g. The carbon black is made by a process wherein an aqueous suspension of carbon black having an AS-number higher than 15 is intimately blended at temperatures within the range 5 DEG and 120 DEG C, under pressure within the range 1 and 20 atmospheres absolute, in liquid phase at a pH-value of 7 to 10, and for a period of 1 to 20 minutes, with vaporizable liquid aliphatic or cycloaliphatic hydrocarbons, the carbon black is separated from liquid matter, then heated and thereby freed from hydrocarbons and water, and finally annealed for 20 to 30 minutes at 200 DEG up to 2200 DEG C. The aqueous suspension is prepared by subjecting hydrocarbons, which are liquid at room temperature, to thermal conversion at 1200 DEG to 2000 DEG C, under pressures within the range 1 and 80 atmospheres absolute, and in the presence of oxygen or an oxygen-containing gas, and water scrubbing the resulting carbon black-containing reaction gas. |
