See more: | PU vs Modified Silicone Sealant | High performance MS sealant AS4001S
| Characteristics | MS Sealant | PU Sealant |
| Chemical base | Modified Silicone Polymer (hybrid, STPE) | PolyUrethane |
| ASTM C920 compliant | Yes | Yes, exceeding |
| Tack free time | <1 hour | > 1 hour |
| Movement capability (ASTM C719) | ±50% | ±25% |
| VOC content | Low VOC, GECA certified green lable for green building | High |
| Containing solvent and Isocyanate (hazardous) | No | Yes |
| Bubbling (caused by isocyanate that reacts with moisture and generates CO2 bubbles in curing process) | No | Yes (the higher the moisture level, the more bubbles) |
| Shrinkage (recessed) after cure (caused by solvent evaporating in curing process) | No | Yes |
| Paintable | Yes | Yes |
| Damp substrate bonding | Yes | No |
| UV resistance | Good | Bad |
| Service life | >10 years | 3-10 years |
| Primerless bonding to most substrades | Yes | No |
| Storage stability/heat resistance | Good | Bad |
| Service temperature | -30oC to +100oC | -40oC to +70oC |
| Price | Competitive against PU | Moderate |
