Mitsubishi Pencil Kabushiki Kaisha

Osaka Gas Company Limited

Katsunori Kitazawa

Masaaki Hoshiba

Noboru Kanba

Toshiyuki Maeda

Michio Saito

Kazutaka Aoki

Yoji Nishimoto

Process for producing sintered color pencil lead

Baked colored pencil lead and process for producing the same

A baked color pencil lead prepared by impregnating pores of a white or light-colored porous baked lead with a dye solution prepared by dissolving a dye in a mixed solvent of polyoxyethylene alkyl ether represented by the following Formula (1) and a low boiling point organic solvent, wherein polyoxyethylene alkyl ether contained in the dye solution is adjusted to 35 to 90% by weight, and then drying to remove the low boiling point organic solvent:

Baked color pencil lead and process for producing the same

There are herein disclosed calcined pencil leads which have a high strength, excellent light resistance and weathering resistance as well as a sharp color and which can easily be erased by an eraser, and a method of manufacturing the calcined pencil leads. In the calcined pencil leads containing, as at least a colorant, a pigment obtained by forming the pigment in the open cells of the pencil leads, the pigment can be obtained by any of (1) a process of impregnating the open cells with a solution containing the dissolved organic pigment, and then solidifying the pigment, (2) a process of impregnating the open cells with a solution containing a pigment precursor, and then reacting it, and (3) a process of impregnating the open cells with a dye solution, and then forming a lake.

Calcined pencil leads and method of manufacturing the same

Non-baked color pencil leads are obtained by forming a blend composition from a filler, a coloring agent, a binder without any wax, and a water/oil repellant substance, kneading the mixture with a solvent and/or plasticizer, extruding the kneaded material, drying the extruded articles to remove the solvent and/or plasticizer therefrom to form open pores therein owing to the less wettability of the water/oil repellant substance, and then impregnating the pores with an oil, a fat and/or a wax. Since the oil, the fat and/or the wax is not blended into the composition, bleeding does not occur at the time of the drying, which permits drying the articles at a high temperature for a short period of time, whereby the manufacturing cost can be decreased. The thus obtained non-baked color pencil leads are remarkably excellent in physical properties such as bending strength and pointed end strength and have a smooth writing performance.

Non-baked color pencil leads and method for preparing same

Novel non-baked color pencil leads are here disclosed which can be obtained by forming a blend composition from a filler, a pigment, a binder and the like without using any wax, at least one of the pigment and the filler being all or partially covered with a fluorinated aromatic compound, kneading the blend composition with a solvent and/or a plasticizer, extruding the kneaded material, drying the extruded articles to remove the solvent and/or the plasticizer therefrom, and then impregnating the porous articles with an oil, a fat and/or a wax. The thus obtained non-baked color pencil leads are remarkably excellent in mechanical properties such as bending strength and pointed end strength, has a smooth writing performance, and permits the drawing of uniform lines. A high-temperature and short-time drying treatment is possible, which can remarkably decrease a manufacturing cost. The color pencil leads which can be erased with an eraser or the color pencil leads which cannot be erased with an eraser can be selectively prepared.

Growing community of inventors

Takasaki, Japan

Katsunori Kitazawa