PURPOSE: To prepare a pencil lead having high soft hardness, by kneading a chlorine-containing resin type binder, an extender material, and a specific amount of ammonium aluminum carbonate hydroxide as essential components, followed by extrusion molding and calcining.
CONSTITUTION: (A) A chlorine-containing resin type binder (e.g., polyvinyl chloride, etc.) is sufficiently kneaded with (B) an extender material (e.g., graphite, talc, etc.), (C) 0.1W20wt% based on component A of ammonium aluminum carbonate hydroxide, a colorant, a plasticizer, a lubricant, a stabilizer, etc. by a mixer, kneader, etc., molded by an extruder, and calcined.
EFFECT: A pencil lead having improved strength, reflectance, and coefficient of friction is obtained, suppressing its deformation during preparation.
SHIMOYAMA SHIN
MIZUNO HIROYUKI
Next Patent: ADHESIVE COMPOSITION, ADHESIVE SHEET, AND ADHESION