Issued Patents 1989
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4880497 | Preparation of water-soluble copolymers containing vinylamine units, and their use as wet strength agents and dry strength agents for paper | Sigberg Pfohl, Heinrich Hartmann, Walter Denzinger | 1989-11-14 |
| 4859642 | Fixed-bed catalyst structure obtained using honeycomb elements | Wolfgang Hoelderich, Peter Kroetzsch, Werner Biffar | 1989-08-22 |
| 4818341 | Production of paper and paperboard of high dry strength | Hans-Juergen Degen, Sigberg Pfohl, Volkmar Weberndoerfer, Gerd Rehmer, Andreas Stange | 1989-04-04 |
| 4814505 | Purification of n-vinylformamide | Willi Schmidt, Alfred Oftring, Theo Proll, Heinrich Hartmann | 1989-03-21 |