| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a burned pencil lead in which flexural strength and a writing concentration are excellent by breaking a negative correlation between the flexural strength and the writing concentration, where negative correlation means that a burned pencil lead obtained by kneading a compound and extrusion molding to a thin line shape, then performing heat treatment to a burning temperature is hardly abraded at a writing time generally when the flexural strength is made high, and even though the flexural strength is larger, however, the burned pencil lead easily becomes that a writing concentration is thin, adversely when the writing concentration is made high, the flexural strength is small, and a lead body easily becomes to be broken by force added at a writing time and impact at a falling time or the like.SOLUTION: Provided is a burned pencil lead that is obtained by blending at least graphite and resin, kneading, extrusion molding to a thin line shape, and then performing heat treatment to a burning temperature. The burned pencil lead includes 1-40 wt.% of graphite whose specific surface area is 100-300 m2/g and whose average grain diameter is 1-5μm as a part of the graphite.</p> |
