| Variables | Actual value | Coded value | ||
| Low level | High value | Low level | High value | |
| Temperatures(˚C), A | 140 | 160 | −1 | +1 |
| Time(minutes), B | 6 | 12 | −1 | +1 |
| Reinforcer/polymer (wt%), C | 40/60 | 60/40 | −1 | +1 |
| Pressure (Mpa), D | 3 | 6 | −1 | +1 |