Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6830610 | Method for increasing the tensile, breaking and flexural strength of colored leads and colored pencils containing the same | Christian Sprogar, Willy Weiss | 2004-12-14 |
| 4332763 | Method of making a cosmetic substance | Matthias Hempel | 1982-06-01 |