Vespel® SP-21 PI is formulated with 15% graphite that imparts greater friction and wear resistance and a lower coefficient of friction compared to Vespel® SP-1. Additionally, the material couples its bearing and wear performance with higher structural rigidity and dimensional stability over a wider temperature range.
Vespel® SP-21 Properties Profile
In both lubricated and non-lubricated components under dynamic load, graphite-filled Vespel® SP-21 provides a significant step up in bearing and wear properties compared to unfilled polyimide. It also has more load-bearing capability based on its higher flexural strength and flexural modulus.
Vespel® SP-21 Availability
Drake offers the full range of Vespel® SP-21 shapes and sizes.
Available from Drake Plastics Inventory:
- Rod diameters: 3.1 – 82.5 mm /0.125 – 3.125 in.
- Max Length: 965.2 mm /38 in.
On thermal performance, Vespel® SP-21 maintains a high degree of its properties from cryogenic temperatures to 350 °C / 662 °F, extending the upper thermal operating range by 50 °C compared to Vespel® SP-1.
Compared to other bearing and wear grades of the polyimide polymer, Vespel® SP-21 also offers higher impact resistance and elongation.
Vespel® SP-21 Typical Applications
Vespel® SP-21 PI’s low wear, load bearing properties and ability to perform from cryogenic to elevated temperatures have led to its specification for a variety of sliding and dynamic load bearing components. Applications include:
- Bearings, flanged and plane
- Bushings
- Seals and seal rings
- Thrust washers
- Valve seats
Vespel® SP-21 Specifications
DuPontTM Vespel® SP-21 is available in the form of isostatically molded billets and unidirectionally pressed slab specified as Type II, Class 1M and Type II, Class 1P respectively according to ASTM D6456-10 / MIL-R-46198. Vespel® SP-21 is specified as Class 2 according to AMS 3644G.
Vespel® is a registered trademark of E.I. DuPont de Nemours and Company
