HCR Silicone rubber composition
HCR (Heat Cured Rubber) is a specialty synthetic elastomer which provides a unique balance of chemical and mechanical properties required by many of today's more demanding industrial applications. From it's original development in the 1940's using a laboratory process to it's final commercial form today, HCR Silicone rubber gives exceptional performance in many different application areas.
Composition / Description The materials consist primarily out of Polydimethylsiloxanes with reactive Vinyl groups and surface treated fumed silica.
For classic products the abbreviated designation VMQ is used. Building in Phenyl groups in the polymer chain leads to an extended low temperature range (PVMQ). By using Trifluorprophyl groups, the resistance against organic solvents, fuels and oils is improved (FVMQ).
Articles made from HCR Silicone Rubber show following interesting properties
Typical Properties
| Shore A, Hardness | approx. 12 - 90 |
| Tensile Strength | approx. 5 - 11 MPa |
| Elongation | approx. 200 - 1000 % |
| Tear Resistance (ASTM D 624 A) | approx. 12 - 40 kN/m |
| Specific Gravity | approx. 1,11 - 1,50 g/cm3 |
| Volume resistivity | approx. 2 x 1015 Ohm x cm |
| Dielectric strength | approx. 20 kV/mm (2 mm sheets) |
| Coefficient of linear thermal expansion | approx. 2-4 x 10-4 |
| Thermal conductivity | approx. 0,2 - 0,3 W x m-1 x K-1 |