| Number | Name | Date | Kind |
|---|---|---|---|
| 1185459 | Worley | May 1916 | |
| 1981413 | Goodfellow | Nov 1934 | |
| 2399119 | Howell | Apr 1946 | |
| 2772764 | McClellan | Dec 1956 | |
| 2997150 | Emanuelson | Aug 1961 | |
| 3011612 | Olsen | Dec 1961 | |
| 3379219 | Schuh | Apr 1968 | |
| 3669503 | Zimmermann | Jun 1972 | |
| 3709345 | Price | Jan 1973 | |
| 3797625 | Price | Mar 1974 | |
| 3807540 | Boulet | Apr 1974 |
| Number | Date | Country |
|---|---|---|
| 557,860 | May 1968 | CA |
| 1,287,370 | Jan 1969 | DT |
| Entry |
|---|
| "Rigid Urethane Foam", DuPont Corp., Wilmington, Del., 1962, pp. 5 and 6. |