| 摘要 |
PURPOSE: An environment friendly solid chalk composition is provided to be scentless, to provide chalks of various colors, and to able to be repeatedly written or removed on black boards of various substrates. CONSTITUTION: An environment friendly solid chalk composition comprises 19-24 wt% of binder, 57-59 wt% of organic/inorganic pigment, 6-7 wt% of talc, 1.5-2 wt% of liquid paraffin, 0.5-1 wt% of citric acid ester, and 11-12 wt% of dimethylsilicone oil, or hydrogen-modified silicone oil of polymethylhydrosiloxane. The binder consists of a mixture of 60-65 wt% of polyethylene wax, 28-32 wt% of stearic acid amide, and 7-8 wt% of Japan wax. |
