| Number | Date | Country | Kind |
|---|---|---|---|
| 4-143922 | Jun 1992 | JPX | |
| 4-237842 | Sep 1992 | JPX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2104000 | Reppe et al. | Dec 1937 | |
| 3085997 | Martin | Apr 1963 | |
| 5196491 | Cho et al. | Mar 1993 | |
| 5272233 | Crivello et al. | Dec 1993 |
| Entry |
|---|
| Higashimura, T et al. (1988) Polymer Preprints 29(2), 1-2. |