Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4843153 | Azo dyes containing thienothiophene radicals as radicals of the diazo component | Heinz Eilingsfeld, Karl-Heinz Etzbach, Helmut Reichelt | 1989-06-27 |
| 4837269 | 2-aminothiophene radical substituted by an electron withdrawing group | Karl-Heinz Etzbach, Ernst Schefczik, Helmut Reichelt | 1989-06-06 |
| 4820809 | Heterocyclic azo dyes | Udo Bergmann, Erwin Hahn | 1989-04-11 |