RUSS MIT HOHEM MODUL UND VERFAHREN ZU SEINER HERSTELLUNG

摘要

1390123 Carbon black CITIES SERVICE CO 23 March 1972 [24 June 1971] 13735/72 Heading C1A A pelletized high structure carbon black is produced by pelletizing a high structure black whilst employing an amount of work during the pelletizing which is such as to reduce the structure of the black as measured by the DBP test by 20 to 40% but without significantly changing the surface area or the volatile content of the black to form a pelletized high structure black having (a) a DPB test value of 100 to 180 cc./100 g. and (b) a volatile content not exceeding about 3 wt. per cent and (c) a surface area (EM) within the range 80 to 180 m.2/g. The bulk density of the pellets is preferably at least 26 lbs./cu. ft. as measured by pour density. In employing the said work, the paracrystalline graphitic units of the carbon black may be worn down in both width and length but remain substantially unshattered during the pelletizing process. Before being subject to the pelletizing process the black may have a DBP test value within the range 120 to 200 cc./100 gm. and a volatile content not exceeding 3% by wt. In the pelletizing process the carbon black may be mixed with a pelletizing liquid and the resulting wetted powder subjected to the action of rapidly moving mechanical members which vigorously agitate and tumble the black until the desired values of the stated parameters are achieved. The wet pellets are then dried and the pellets produced recovered. The pelletizing liquid may be water or an aqueous solution of a binder, which may be mixed with the black in a weight proportion in the range 65 : 35 to 35 : 65. During pelletisation the wetted mass of black passes through an elongated path where it is subjected to a multiplicity of impacts by elongated agitating members which extend outwardly from a rotatable shaft which extends axially with respect to the elongated path, and said members have a tip velocity of at least 80 f.p.s. during movement through the wetted mass. The particles are preferably dried under conditions which preclude the substantial addition of oxygen to the black. The pelleted black is used as a filler in a compounded rubber employed as a treadstock material and having a wear resistance 90% to 110% of that of a comparison composition containing the same amount of black in a similar rubber batch.