Vitreous carbon and process for preparation thereof

Claim 1

A process for preparing a vitreous carbon from a solid thermosettable intimate blend comprising 30-76 percent by weight of a finely divided carbonaceous particulate filler and 24-70 percent by weight of a finely divided phenolic resin mixture comprising 20-80 parts by weight of a phenolic-furfuraldehyde Novolak resin, which is fusible upon heating, and 20-80 parts by weight of a phenolic-aldehyde resol resin, which is thermosettable upon heating, the sum of said parts of Novolak and resol resins totaling 100 parts by weight, the aldehyde in said Novolak comprising at least 50 molar percent of furfuraldehyde, comprising the steps of: (1) grinding said phenolic furfuraldehyde Novolak resin to a particle size of less than 40 mesh on a U.S. Standard sieve; (2) grinding said phenolic-aldehyde resol resin to a particle size of less than 40 mesh on a U.S. Standard sieve; (3) mixing said ground resins together with said finely divided carbonaceous powder to a homogeneous mixture; (4) molding the resultant mixture at a temperature of 100°-180° C. and a pressure between 500 pounds per square inch and 8 tons per square inch; and (5) heating the resultant molded product gradually up to a temperature of 600°-700° C. with the temperature increased at a rate of 1°-5° C. per hour, then above the range of 600°-700° C. at an increasing rate of 10°-50° C. per hour up to 800°-850° C. and thereafter at 20°-25° C. per hour up to a maximum temperature of 1800°-3000° C., which maximum temperature is held for at least 24 hours.