| 摘要 |
PROBLEM TO BE SOLVED: To provide a baked pencil lead and its manufacture wherein a written drawing line is pitch-black, has little glossiness, and is excellent in a writing tone, and is excellent in bending strength, modulus of bending elasticity, and orientation degree of flake-like body material. SOLUTION: A baked pencil lead is provided wherein carbon as bonding material carbonated material, and boron nitride as body material are blended, orientation degree (π) in an extrusion axial direction of boron nitride obtained by X-ray diffraction is 0.85 or over, modulus of bending elasticity of the lead is 60GPa or over, and bending strength is 250MPa or over. It is extrusion molded by a manufacturing method wherein back pressure just above an extrusion nozzle in extrusion molding is at least 300kg/cm<2> , and shear rate when molten slurried kneaded material passes through a nozzle becomes at least 5×10<4> (1/sec).
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