METHOD FOR INCREASING THE TENSILE, BREAKING AND FLEXURAL STRENGTH OF COLOURED LEADS AND COLOURED PENCILS CONTAINING THE SAME

摘要

The invention relates to a method for increasing the tensile, breaking and flexural strength of coloured leads. The method is characterised in that 1 to 50 percent by weight alkyl and/or hydroxyalkyl cellulose which are soluble in organic solvents and whose alkyl radicals can be straight-chained or branched are added to the lead substance. The invention also relates to coloured pencils containing said coloured leads.