Absence of air during hot-pressing phases can be of importance. It is favorable to decrease the temperature before e.g. opening the press. Reduction to around 120 °C (250 °F) is generally recommended. This may require 1 to 2 minutes of cooling time or be realized via active cooling. Membranes are delivered in acid form (>99,9 % SO3H). A cleaning with H2SO4 or HNO3 and H2O2 can be helpful but is not necessary in general.
Processing via CCM routes
When building MEA via catalyst-coated membrane (CCM) intermediates the application of Decal routes has evolved as state of the art. To combine the material in a way such that intense contact with low resistance is developed between membrane and catalyst layers, we recommend the following baseline parameters as a starting point for individual optimization of the transfer process:
for E87 series membranes
- Temperature 200 °C (390 °F)
- Press pressure between 1 and 5 MPa (150-700 psi)
- Hot-pressing times between 2 and 5 minutes
- Higher temperatures can require shorter hot-pressing times
Processing via GDE routes
If, however, internal customer processes foresee lamination of gas-diffusion electrodes (GDE) together with the ionomer membrane, slightly different parameters are preferable:
for E87 series membranes
- Temperature 150-160 °C (300-320 °F)
- Respect of pressure limitation by GDL/microporous layer
- Hot-pressing times between 0.5 and 2 minutes
- Higher temperatures can require shorter hot-pressing times
