PTFE vs silicone coated fiberglass: how to choose
Both coatings sit on the same fiberglass platform and both survive temperatures that destroy ordinary fabrics. They are not interchangeable. The choice comes down to four measurable differences.
Working temperature range
PTFE coated fabric (the 90 series) carries a continuous working range of -140~260°C — the widest window on the platform. That lower limit is why it shows up in cryogenic wrapping and outdoor insulation duty, and the upper limit covers oven liners and sealing belts.
Silicone coated fiberglass (5025–5300) is rated -70~260°C. For nearly every factory process the two overlap; it is the extreme low end where only PTFE qualifies.
Electrical performance
This is where silicone pulls ahead. The 5025–5300 range holds a dielectric constant of 3–3.2 and breakdown voltage of 20–50 kV/mm depending on thickness, across twelve models from 0.25 to 3.0mm. Insulation cloth, welding blankets and non-metallic compensators on power infrastructure default to silicone.
PTFE cloth insulates too, but when a spec sheet names a breakdown voltage requirement, silicone coated fabric is the line engineered to meet it in writing.
Release and friction
PTFE is the lower-friction surface — it is the release coating on heat-sealing bars, mould liners and conveyor surfaces where product must not stick. If the job description contains the words "non-stick", start with PTFE.
Silicone releases well but its advantage is elasticity: it stays flexible across the range, which is why compensators and sleeves that must flex thousands of cycles use silicone rather than a stiffer PTFE build.
Thickness and format availability
PTFE cloth runs 0.08–0.90mm in four grades, coated up to 4,000mm wide — the heaviest grade (9090) reaching 6,000 N/5cm² tensile. Silicone fabric spans 0.25–3.0mm; the thick end is reserved for expansion joints and heavy anti-corrosion wrapping that needs body.
Rule of thumb from the platform: below 0.25mm you are choosing PTFE by default; above 0.90mm you are choosing silicone; between the two, let temperature extremes and dielectric requirements decide.
Quick decision table
Oven and microwave liners, heat-sealing release, wide conveyor belts, cryogenic wrapping → PTFE coated fabric. Electrical insulation with stated kV/mm, pipeline compensators, tank anti-corrosion layers, anything that must stay flexible → silicone coated fiberglass.
Still between the two? Send both the application and the spec you must meet — a grade recommendation with numbers comes back in one reply.
Direct Factory Solutions Mentioned in This Guide
Manufactured and QC-tested in our Taixing facility. Request technical data sheets or free testing samples.
PTFE Coated Fabric · 90 Series
High-temperature fabric 0.08–0.90mm, widths up to 4,000mm, continuous duty -140~260°C.
Silicone Coated Fiberglass Fabric · 5025–5300
12 standard models from 0.25 to 3.0mm, dielectric breakdown 20–50 kV/mm, high elasticity.