Patent ID: 7704481

Claim:
A method for producing vapor-grown carbon fibers having a diameter of 10 nm to 150 nm, consisting essentially of contacting a carbon compound with a catalyst and/or a catalyst precursor compound in a heating zone to produce carbon fibers in a vapor phase, wherein the carbon compound is a combination of at least one compound selected from compounds in the following Group (a) and at least one compound selected from compounds in the following Group (b): Compound of Group (a): carbon compounds having no benzene ring structure within the molecule Compound of Group (b): aromatic compounds, the ratio of the number of atoms of an element as the catalyst in raw materials to the number of all carbon atoms is: (number of atoms of element as catalyst)/(number of all carbon atoms)=0.000005 to 0.0015, the compound of Group (a) and the compound of Group (b) satisfy the condition: [number of carbon atoms contained in compound of Group (a)]/[number of carbon atoms contained in compound of Group (a)+number of carbon atoms contained in compound of Group (b)]=0.001 to 0.9, and the residence time in a temperature region of 600° C. or more is 30 seconds or less.