| abstract |
The vitreous carbon disclosed herein is prepared from intimate uniform mixtures of powder or otherwise blendable form of 20-80% by weight of a solid phenolic-aldehyde Novolak resin and of 20-80% by weight of a solid phenolic-aldehyde resol resin, the percentages being based on the combined weight of the Novolak and resol resins, and the aldehyde in said Novolak resin comprising at least 50 molar percent, preferably substantially 100 percent, furfuraldehyde, together with a carbonaceous filler, preferably graphite, in a proportion as high as 76% by weight based on the total composition. Generally the graphite may comprise 30-70%, advantageously 35-65% and preferably 40-60% of the molding composition. The vitreous carbon is improved in electrical properties and in the capability of being shaped into large thin plates which are much more stress-free than otherwise produced. The intimate mixture of the resins used for this preparation is advantageously made by blending resin components having a particle size of less than 40 mesh, preferably less than 100 mesh. |