Patent · US Expired

Method for increasing the tensile, breaking and flexural strength of colored leads and colored pencils containing the same

US6830610B1 · kind B1 · utility

5Cited by

10References

18Claims

0Family size

Assignee

SCHWAN-STABILO COSMETIC GMBH & CO. KG · DE

Inventors

Werner Bruchert · Nuremberg, DE
Christian Sprogar · Bubenreuth, DE
Willy Weiss · Altdorf, DE

Key dates

Filing date	Apr 15, 2003
Grant date	Dec 14, 2004
Priority date	—
Expiry date	Apr 15, 2023

Classification

Technology area (CPC A)Human Necessities
CPC primaryA61K2800/872
WIPO fieldPharmaceuticals
WIPO sectorChemistry

Abstract

A method for increasing the tensile, breaking and flexural strength of coloured leads. The method is characterized 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.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.