The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 21, 1997
Filed:
Mar. 18, 1996
Masaaki Hoshiba, Fujioka, JP;
Kazutaka Aoki, Iwata, JP;
Mitsubishi Pencil Kabushiki Kaisha, Tokyo, JP;
Abstract
A baked color pencil lead which can draw lines showing a vivid color and having excellent light fastness while holding excellent physical strength, and which is manufactured by a method comprising the steps of: kneading a blend composition comprising at least a filler and an organic forming binder, molding the composition by extrusion, and baking the molded composition in a non-oxidizing atmosphere, to thereby form a first baked lead containing a binder of a carbon produced by carbonizing the above organic forming binder, heating the first baked lead in an oxidizing atmosphere to remove the binder of the carbon by oxidation, to thereby form a second baked lead, impregnating the pores of the second baked lead with a perhydropolysilazane-containing solution and then subjecting it to a heat treatment in an inert atmosphere such as a nitrogen atmosphere or in an ammonia atmosphere, to thereby form a third baked lead containing silicon nitride produced by the heat treatment, and impregnating the pores of the third baked lead with an organic pigment solution and solidifying the organic pigment in the pores to allow at least the organic pigment to be contained in the baked lead as a colorant.