Issued Patents 1989
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4870689 | Ear wax barrier for a hearing aid | — | 1989-09-26 |
| 4847419 | Process for the preparation of bifunctional tertiary aromatic phosphine sulfides, and also several specific representatives of this class of compounds | Hans-Jerg Kleiner | 1989-07-11 |
| 4816605 | Process for the preparation of bifunctional tertiary aromatic phosphine oxides | Hans-Jerg Kleiner | 1989-03-28 |
| 4806691 | Process for the preparation of tertiary phosphine oxides | — | 1989-02-21 |