Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4828570 | Tanning agent and a process for its preparation | Ulrich Riegel, Fritz Engelhardt, Kuno Reh, Helmut Croon, Werner Lotz | 1989-05-09 |
| 4822372 | Processing for tanning leather | Frank Forster, Karlfried Keller, Werner Lotz | 1989-04-18 |
| 4810252 | Process for tanning leather | Werner Lotz, Karlfried Keller | 1989-03-07 |