| abstract |
Non-baked colour pencil leads are obtained by kneading together a water/oil repellent substance, a filler, a colouring agent and a binder, optionally, with a solvent (water) and/or a plasticizer without using a wax, extruding the kneaded composition, drying the extruded article to remove the solvent/plasticizer so that open pores are formed owing to the low wettability of the water/oil repellent substance, and then impregnating the porous articles with an oil, fat or wax. The water/ oil repellant substance may be graphite fluoride, carbon fluoride, fluoro-resin powder (such as PTFE), graphite or boron nitride and preferably makes up between 2 and 20% by weight of the total blended composition. <IMAGE> |