Mina de lápiz

• Main Authors: BANZAI, Satoru, ARAI, Hiroyuki
• Format: Patent
• Language: Spanish
• Published: 14.02.2022
• Subjects: ADHESIVES; BUREAU ACCESSORIES; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; CORRECTING FLUIDS; DYES; FILLING PASTES; IMPLEMENTS FOR WRITING OR DRAWING; INKS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PERFORMING OPERATIONS; POLISHES; TRANSPORTING; USE OF MATERIALS THEREFOR; WOODSTAINS; WRITING OR DRAWING IMPLEMENTS

Una mina de lápiz que comprende un cuerpo de mina horneada, en donde: una superficie del cuerpo de mina horneada está cubierta por una capa de recubrimiento hecha de resina, y una dureza al rayado de la resina que constituye la capa de cobertura es HB o mayor, la dureza al rayado de la resina como resina sujeta se define como el índice de dureza más bajo de un lápiz de prueba que puede formar una hendidura en la superficie de una placa plana horizontal recubierta con una película de 5 μm de espesor de la resina en cuestión, cuando la superficie se raya al presionar el lápiz de prueba sobre la superficie en un ángulo de 45º con una carga de 7.355 N, en un estado en el cual un extremo de la punta de una mina del lápiz de prueba se ha dejado en forma cilíndrica a la vez que su extremo distal se ha reducido en un plano liso. 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.