PPG PR-1995 Class B is a primerless, two-part firewall sealant based on silicone polymer, designed for sealing firewall structures against the passage of air and vapours. The cured compound has a service temperature of −54 °C to 204 °C (−65 °F to 400 °F), withstands flash temperatures up to 1927 °C (3500 °F) and remains an effective sealant after long-term exposure to phosphate ester hydraulic fluids. The B-2 grade has a 2-hour application life.
Application Properties
- Colour: Part A and Part B grey; mix ratio by weight A : B = 10 : 100
- Application life: 2 hours; initial slump 3.8 mm (0.15 in)
- Cure at 25 °C: 35 Shore A at 24 hours, 50 Shore A at 7 days
Performance Properties
- Cured specific gravity 1.62; non-volatile content 98%
- Shear strength: 2070 kPa (300 psi) after 7 days at 25 °C; 1173 kPa (170 psi) after a further 7 days at 204 °C
- Tensile strength 2415 kPa (350 psi); elongation 110% (after 7 days in phosphate ester: 1720 kPa, 100%)
- Flame resistance: no flame penetration at 1093 °C for 15 minutes or at 1927 °C for 3 minutes
- Low-temperature flexibility: no cracking at −54 °C
Packaging and Storage
- Two-part can kits, Semco® cartridges, premixed and frozen (PMF) Semco® cartridges
- Kits and cartridges: at least 9 months below 27 °C; PMF cartridges: at least 30 days below −40 °C
| Packing | 1 Pint |