Nitto No.903UL vs No.973UL-S

Construction, purpose, and documented performance

Compare PTFE film and PTFE-impregnated glass-cloth tape construction for heat-resistant insulation and release.

Choosing tape for a heat-seal or release surface

The starting difference is the backing, not the shared PTFE name. No.903UL uses PTFE film; No.973UL-S uses PTFE-impregnated glass cloth. Both records specify silicone adhesive, but that alone does not make the two tapes interchangeable.

For an existing heat sealer, start with the equipment specification and the complete model on the old roll. Compare the required surface finish and backing construction before changing material. A tape that looks similar or fits the same width may still behave differently in the assembly.

Use the manufacturer data linked in the table to confirm the exact grade and thickness. A published temperature range is not a guarantee of service life on your machine: check the actual contact conditions and the equipment maker's replacement procedure. Validate a proposed change in a controlled trial before using it in production.

What to check before changing tape

• Identify the current roll's full model, thickness, width and length; include a label photo if available.
• Describe the contact surface, material being sealed and whether the tape provides release, sliding or insulation.
• Provide operating temperature, contact time, pressure and cleaning conditions for application review.
• Confirm any food-contact or electrical compliance requirement separately; an application example is not an approval for every assembly.
• Send the quantity and cutting requirements with the specification when requesting a quotation.