In electrical equipment, transformers, and chemical processing systems, insulating gaskets serve a critical role – they prevent electrical leakage, withstand heat, resist chemicals, and maintain mechanical integrity under compression. Conventional materials each have limitations: mica is brittle, rubber degrades under heat, and pure PTFE creeps under sustained load.
PTFE high-temperature cloth (PTFE-coated fiberglass) solves these problems. It combines the electrical insulation of PTFE with the mechanical strength and dimensional stability of fiberglass.
Aokai PTFE manufactures PTFE insulating gaskets in various thicknesses and sizes. This guide explains ten key advantages over conventional gasket materials.
Excellent Electrical Insulation – Reliable Across Conditions
PTFE cloth insulating gaskets deliver outstanding electrical insulation across a wide range of operating conditions.
1. High dielectric strength and resistivity
The material features high volume resistivity and surface resistivity together with superior breakdown voltage, delivering reliable insulation even at ultra-thin gauges. Its dielectric constant and dissipation factor remain low across a wide frequency spectrum, making it ideal for high-frequency and high-voltage applications.
2. Stable under humidity and temperature
Unlike many insulating materials that absorb moisture and lose dielectric strength, PTFE cloth's insulating properties barely fluctuate with temperature and humidity. It maintains stable performance under damp and hot environments, effectively preventing creepage and dielectric breakdown.
Ultra-Wide Operating Temperature Range – From -70°C to 260°C
Continuous service temperature ranges from -70°C to 260°C, with short-term heat resistance exceeding 300°C. Within this temperature band, the gasket will not soften, deform, or decompose – unlike ordinary plastic or rubber gaskets.
Thermal resistance comparison:
Polyester film – degrades above 150°C
Epoxy board – limited to 180°C
Rubber gaskets – harden and crack above 200°C
PTFE cloth – stable at 260°C continuous
Universal Chemical Resistance – "The King of Plastics"
Nicknamed "the King of Plastics", PTFE withstands nearly all strong acids (including aqua regia), strong alkalis, organic solvents, and oils. Even after long-term immersion in corrosive liquids or exposure to highly reactive chemicals, the gasket will not swell, embrittle, or degrade.
This trait is especially critical for insulation components in chemical, electroplating, and semiconductor equipment where corrosive media are present.
Non-Stick Surface – Anti-Contamination and Creepage Prevention
With ultra-low surface energy, PTFE cloth repels dust, oil stains, moisture, and chemical residues to keep the surface clean during long-term service. Under humid and polluted conditions, conductive paths are hard to form – effectively suppressing creepage and elevating electrical safety.
The non-stick property also simplifies maintenance drastically; cleaning can be done simply by wiping or self-cleaning.
High Tensile Strength and Dimensional Stability – No Creep
The fiberglass substrate endows the material with excellent tensile strength, tear resistance, and dimensional stability, resisting crushing, elongation, and thermal shrinkage. It maintains uniform thickness and flatness under heat and compression, ensuring high assembly precision.
Key advantage – no cold flow (creep)
Unlike pure PTFE sheets, which are prone to cold flow (creep) under sustained clamping force, PTFE high-temperature cloth gaskets maintain stable thickness and insulation gaps over long-term use. The fiberglass reinforcement prevents the PTFE from slowly extruding out under pressure.
Aokai PTFE test data: Pure PTFE gaskets can thin by 15-25% after 100 hours of compression at 200°C. PTFE cloth gaskets show <5% thickness change under the same conditions – maintaining consistent insulation clearance.
Low Friction Coefficient – Wear Resistance and Noise Reduction
PTFE has an extremely low friction coefficient of 0.05–0.1. When applied as insulating pads for sliding parts or vibrating equipment:
Reduces abrasion
Eliminates noise
Avoids circuit contamination caused by friction-generated powder debris
This is particularly valuable for insulating gaskets used in switchgear, motor housings, and vibration-prone equipment.
Outstanding Aging and Weather Resistance
PTFE cloth gaskets resist ultraviolet radiation, oxidation, mold, and hot-humid environments. Even after long-term outdoor exposure or alternating high-low temperature cycles, they will not harden or crack like rubber gaskets.
Service life: PTFE cloth gaskets typically last 5-10x longer than conventional rubber or plastic insulation materials in outdoor and high-temperature environments.
Flexible Processing – Easy Installation
PTFE cloth gaskets can be cut into arbitrary shapes with scissors, die cutters, or laser cutters.
Back adhesive options – available for fast sticking and positioning
Flexible fabric substrate – conforms to curved or irregular surfaces
Thickness range – from 0.08 mm to over 1 mm to satisfy diverse voltage resistance and space constraints
Flame Retardant and Non-Toxic – Safe for Critical Applications
PTFE achieves a high flame retardancy rating (generally UL94 V-0), self-extinguishing once away from fire without supporting combustion.
Many grades of PTFE high-temperature cloth comply with FDA food contact standards – non-toxic and odorless, safe for insulation in medical and food packaging machinery.
Versus mica sheets: PTFE cloth is flexible, shatterproof, easier to process and install, and offers superior moisture resistance.
Versus rubber or plastic insulating gaskets: PTFE cloth offers one grade higher in temperature tolerance, chemical resistance, and anti-aging capacity.
Versus pure PTFE thin sheets: PTFE cloth resists cold flow and creep, with higher mechanical strength and better dimensional stability – more suitable for long-term clamped insulation scenarios.
Summary – The Optimal Choice for Demanding Insulation Applications
PTFE high-temperature cloth gaskets serve as an optimal choice for scenarios demanding strict temperature resistance, voltage endurance, high cleanliness, and long service life:
High-frequency transformers
Motor slot insulation
Heat sealer insulation
Internal isolation for electrical appliances
Chemical flange insulation
Semiconductor equipment
Aokai PTFE offers PTFE cloth insulating gaskets in custom shapes, thicknesses, and adhesive backing options. We can provide dielectric strength test reports and material certifications upon request. Contact us with your insulation requirements and voltage ratings.
If you wish to obtain detailed specifications, application scenarios and customized solutions for our full product portfolio including PTFE high-temperature cloth, PTFE high-temperature adhesive tape, PTFE high-temperature mesh belt, seamless heat press belt, single-sided PTFE fabric, high-temperature resistant conveyor belt and heat-resistant fiberglass cloth, please contact us via the information below:
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