Stationery Tips

Lead of mechanical pencils

Raw material for Spare Leads

The first was the sintering of the clay, which is the main raw material, the graphite and the binder, as well as the pencil core. However, it was not possible to obtain enough strength when the core diameter was thinned, and it was about 1.0, 1.5 mm. After that, a thin, strong core was demanded, and the method to bake the organic matter and the binding agent was discovered, and the present polymer firing core was developed. The raw material is graphite and polymer resin, but the finished core is 100% carbon because the resin is carbonized.

Back to Stationary Tips


Digital catalog is available for online reading.

General Info Catalog

General Information of Tombow 2022-2023 Lineup of all products of Tombow

Open the catalog

Eco Info Catalog

Information and lineup of environmental products of Tombow

Open the catalog

Downloadable PDF version is available.

Catalogs can be viewed and saved in smartphone, tablet and PC in use of “iCata” digital catalog service.

Product information in catalogs is created at the time of catalog production. Please note that design, specification and other information may change without notification.