Table 2.
Basic properties of UF resins prepared with different levels of the first and second initial F/U mole ratios.
| 1st initial molar ratio | 2nd initial molar ratio | Non-volatile solids content (%) | Viscosity (mPa.s) | Gelation time (s) | Free formaldehyde (%) | Specific gravity | pH |
| 2.0 | 2.0 | 58.2 ± 0.5 | 181 ± 1 | 205 ± 4 | 0.47 ± 0.03 | 1.20 | 8.2 |
| 3.0 | 61.1 ± 0.3 | 197 ± 3 | 154 ± 4 | 0.38 ± 0.03 | 1.20 | 8.2 |
| 4.0 | 62.4 ± 0.5 | 210 ± 3 | 178 ± 3 | 0.38 ± 0.04 | 1.21 | 8.2 |
| 2.0 | 1.7 | 58.4 ± 0.9 | 185 ± 2 | 210 ± 2 | 0.42 ± 0.02 | 1.20 | 8.2 |
| 3.0 | 61.9 ± 0.8 | 198 ± 3 | 152 ± 2 | 0.30 ± 0.02 | 1.20 | 8.2 |
| 4.0 | 62.4 ± 1.0 | 215 ± 2 | 159 ± 3 | 0.23 ± 0.02 | 1.21 | 8.2 |