Abstract: The disclosed carbon fiber felting material has a bulk density of 0.01 to 0.5 g/cm.sup.3 and a thermal conductivity of at most 1.0 kcal/m.multidot.hr.multidot..degree.C. in the thickness-wise direction thereof at 2,200.degree. C. The carbon fiber felting material is formed through physical and/or chemical interfiber entanglement. The carbon fiber felting material is very stable in an inert atmosphere, and excellent in heat insulating properties in a high-temperature range and against radiant heat transfer in particular.

Abstract: Pitch-based carbon fiber having from 2 to 200 twists per 1 cm length or from 2 to 200 twists per 1 cm length and curls are provided. These fibers show superior properties as carbon fibers useful for non-woven fabrics or for fabrics.

Abstract: An infusiblized, or infusiblized and slightly carbonized fiber of optically anisotropic pitch type is combined with a phenolic resin fiber to produce a high bulk density carbon fiber structure in the form of a laminate of mutually entangled carbon fiber sheets with improved handleability of fiber sheets and improved stability of a laminate structure formed through entanglement. A high flexural strength carbon-carbon composite material with a high volume fiber content is produced by impregnation with a precursor of carbon and subsequent carbonization of the carbon fiber structure of the kind as described above or a fiber laminate of mutually entangled sheets of the infusiblized, or infusiblized and slightly carbonized fiber of optically anisotropic pitch type blended with the phenolic resin fiber.

Abstract: A process is provided for producing non-woven fabrics in which adhered points supporting the non-woven fabrics structure are the same carbon materials with the component fibers and which is superior in strength, dimensional stability, heat-resisting property, chemical resistance, electric conductivity, etc.This process comprises mixing spun pitch fibers or insufficiently infusiblized pitch fibers with infusiblized pitch fibers or carbonized pitch fibers, shaping the mixture into a sheet or the like and thereafter carbonizing the shaped mixture in the atmosphere of an inert gas to mutually fix the component fibers by utilizing the adhering property of the spun pitch fibers or the insufficiently infusiblized pitch fibers during the carbonization.