Validated where the temperature never drops.
Aperflu 3075 is the only grade in the family validated by compression-set testing at 300 °C × 70 h — and it still returns 17%. For continuous high-temperature service, that figure is the difference between planned maintenance and an unplanned shutdown.
At 70 Shore A with 21.5 MPa tensile it keeps useful mechanical strength at temperature, and the full 290 °C two-stage post-cure removes residual volatiles that would otherwise cause outgassing in sealed systems. Intended for energy, oil & gas and aerospace hot sections.
The same elongation (160%), 42% more tensile strength — and a compression set that is lower even when measured 96 °C higher. Aperflu 3075 is validated at 300 °C × 70 h, where it returns 17%; Kalrez 6375 publishes 24% at 204 °C and a 275 °C continuous ceiling. Read the set figures with that temperature gap in mind.
| Property | Aperflu 3075 | Kalrez 6375 |
|---|---|---|
| Hardness | 70 Shore A | 75 Shore A |
| Tensile strength at break | 21.5 MPa | 15.16 MPa |
| Elongation at break | 160 % | 160 % |
| Compression set, 70 h | 17 % @ 300 °C | 24 % @ 204 °C |
| Set test temperature | 300 °C × 70 h | 204 °C × 70 h |
| Max. continuous service temp. | Not published | 275 °C |
Highlighted cells indicate the more favourable published value.
42% higher tensile strength (21.5 vs 15.16 MPa) at the same 160% elongation, and a 17% compression set measured at 300 °C — 96 °C hotter than the condition behind 6375's 24%. Mechanical strength and set resistance both hold up in the range where 6375 has no published set data.
A published 275 °C continuous ceiling and 5 Shore A more hardness, which buys extrusion resistance under high differential pressure. 3075 publishes no continuous ceiling of its own — its 300 °C claim rests on a single 70 h set validation, not on a rated service window.
Continuous high-temperature static sealing where strength and set retention matter most: 3075. Broader chemical service up to 275 °C with a documented ceiling and a harder, more extrusion-resistant seal: 6375.
Kalrez® and Spectrum™ are trademarks of DuPont de Nemours, Inc. Kalrez 6375 values are taken from DuPont published technical information (Rev. 4, July 2019); Aperflu 3075 values are taken from its compound technical data sheet. All figures are typical values, not specifications. The compression-set figures are NOT measured at the same temperature (300 °C vs 204 °C) and the specimens differ (Aperflu button vs Kalrez pellet / O-ring #214) — treat them as an indication of high-temperature capability, not as a like-for-like ranking. Confirm selection with immersion testing in the actual process fluid.
Hot process lines, exhaust-side seals and high-temperature valve trim.
Combines heat resistance with resistance to H₂S and production chemicals.
Engine-adjacent sealing where thermal margin is deliberately thin.
Send us your media, temperature and pressure profile — we will recommend the grade.