| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a pencil lead which is improved in handwriting density without degrading breakage strength. <P>SOLUTION: The pencil lead is manufactured by impregnating pores of a fired lead body with an impregnation component containing one or more kinds selected from copolymers of at least 1, 1'-methylene-bis(4-isocyanatocyclohexane) and a polyalkylene glycol. <P>COPYRIGHT: (C)2010,JPO&INPIT |
