| 摘要 |
PROBLEM TO BE SOLVED: To obtain a pencil lead having subdued gloss of written line and developing pure black color by adding lithium cobalt titanate to a pencil lead composed of a body material produced by using an organic binder in combination with graphite and talc. SOLUTION: This pencil lead can be produced by adding (A) lithium cobalt titanate to a body material composed mainly of (B) an organic binder and (C) a combination of graphite and talc, kneading the mixture, extruding in the form of a thin strand and subjecting to baking treatment and oil- impregnation treatment. The component A is powder having particle diameter of preferably <=25μm, more preferably <=5μm. The amount of the component A is preferably 0.5-20wt.% based on the talc in the component C. The talc in the component C is preferably a flaky talc such as a wet-pulverized talc. The pencil lead is expected to be usable especially as a thin pencil lead such as the lead for a propelling pencil because the lead has high talc abrasion rate, high written line density and practical strength.
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