What is the difference between uniaxial and transverse sealing tape

Update:01-03-2022
Summary:

The main issue with mono-axial PTFE Tape OEM gasket tap […]

The main issue with mono-axial PTFE Tape OEM gasket tapes is that due to the orientation of the fibrils being in only one direction, the material is susceptible to tearing/splitting when tension is applied in the transverse direction. On the other hand, the material exhibits immense compressibility, allowing it to form a perfect seal with minimal pressure and retain its form over a range of temperatures. As such, the tape works brilliantly in applications such as flange-to-flange connections, where the assembly is not intended to be dismantled frequently, once installed.

However, in applications where the frequent opening of the system occurs, the mono-axial tapes fail over the medium-long term. For example, using mono-axial tape along the rim of a vessel that is opened multiple times a day would not work, since the constant application and relaxation of pressure would cause the fibrils to come loose and the tape to slowly disintegrate. Furthermore, with very poor recovery  mono-axial tape is soft but lacks elasticity  the seal becomes less effective each time the lid is closed and opened again.

To remedy this, we set out to create a cross-directional tape that would allow for strength in the transverse direction and be ideal in applications where recovery was needed. Within the industry, there are already ePTFE sheets that are made using multi-directional ePTFE layers.The challenges thrown by PTFE as a material are myriad.

As we have already illustrated in various articles, the processing techniques needed for PTFE differ from those of other polymers so dramatically, that nearly every end-product requires a special-purpose machine that can be used for no other plastic. The main reason for this is that PTFE is not melt-processable. As a result, heating the polymer into a liquid state to then either mould or extrude it is not possible. Hence, we end up with processes such as paste extrusion , skiving PTFE tapes, and isostatic moulding moulded PTFE parts.