Title:
鉛筆芯
Document Type and Number:
Japanese Patent JP7092666
Kind Code:
B2
Abstract:
In a pencil lead manufactured through a baking step regardless of being a black lead or a colored lead, the mechanical strength of the pencil lead is further increased by coating a surface thereof with a resin. A pencil lead comprises a baked lead body whose surface is covered by a covering layer made of resin that has a scratch hardness of HB or greater. The scratch hardness of the resin as a subject resin is defined as a lowest hardness index of a tester pencil that is able to form an indentation on a surface of a horizontal flat plate coated with a 5-µm thick film of the subject resin, when the surface is scratched by the tester pencil being pressed onto the surface at an angle of 45° with a load of 7.355 N, in a state in which a tip end of a lead of the tester pencil has been left in a cylindrical shape while its distal end has been shaved in a flat plane.
Inventors:
Hiroyuki Arai
Satoshi Sakanishi
Satoshi Sakanishi
Application Number:
JP2018529420A
Publication Date:
June 28, 2022
Filing Date:
June 12, 2017
Export Citation:
Assignee:
MITSUBISHI PENCIL CO.,LTD.
International Classes:
B43K19/02; C09D13/00
Domestic Patent References:
| JP7034024A | ||||
| JP2008189873A | ||||
| JP2002348516A | ||||
| JP2013071964A | ||||
| JP2011528046A |
Attorney, Agent or Firm:
Patent Service Corporation Taiyo International Patent Office