Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4915742 | Iron blue pigment, process for its pigmentation and use | Everhard Gratzfeld, Heinrich Winkeler | 1990-04-10 |
| 4378995 | Iron blue pigment, process for making the same and use | Everhard Gratzfeld, Helmut Reinhardt, Hans Schaefer | 1983-04-05 |
| 4368075 | Iron blue pigment, process for making the same and use | Everhard Gratzfeld, Helmut Reinhardt, Hans Schaefer | 1983-01-11 |