What is the difference between tape and thread sealing tape

Update:19-04-2022
Summary:

There are many key differences in the production proces […]

There are many key differences in the production process. Thread sealing tapes are made by extruding teflon beads followed by various calendering, slitting and winding operations. The end result is an unsintered PTFE tape with a thickness of approximately 0.075 mm (75 microns). Sintering is the process by which PTFE is cured at high temperatures to achieve its final properties. Unsintered PTFE tape is basically still "raw material" that has been pulled flat and flattened into tape form.

Expanded polytetrafluoroethylene (ePTFE) tape is also made by first extruding the tape. However, the tape then goes through a drying process and then passes through a stretcher at high temperatures. The stretching process requires CNC control to ensure that the stretching rate, speed and temperature are maintained within tight parameters. The resulting tape is typically 0.25mm to 15mm thick.

The fact that thread sealing tapes are calendered, unsintered tapes, while ePTFE tapes go through a process of stretching and heating is why the tapes exhibit such different properties. In fact, the rapid rate at which the ePTFE tape is stretched and heated means that it is also not "fully sintered" as one would call it. However, the stretching process intentionally does not cure the PTFE above its melting point to ensure that certain properties are retained.

In contrast, PTFE Thread Seal Tape have a range of properties in addition to sealing that make them critical in many industries. First, as a sealing material, ePTFE is used where not only sealing is required, but sealing needs to be able to withstand high pressures (up to 100 bar), high temperatures (up to 250°C), and resist a range of aggressive chemicals. Attempting to use a simple thread sealing tape in such a harsh environment will cause the tape to degrade almost immediately because it lacks the mechanical strength to withstand the same conditions.