Microcellular, Multi-Directionally Expanded, and Microsphere-Filled PTFE Soft Sheet
PTFE Foam Sheet
PTFE foam sheet covers a family of highly compressible PTFE gasket materials engineered for low bolt-load sealing on fragile, damaged, or non-metallic flanges. Whether achieved through multi-directional expansion (Soft-Chem type), glass microsphere fillers (Novaflon type), or layered microcellular construction (Gylon 3545 type), these materials conform to irregular surfaces at a fraction of the bolt load needed for virgin PTFE. We stock foam and microcellular PTFE sheet for glass-lined vessels, enamel equipment, FRP flanges, and any joint where overtightening risks flange damage. Note: this is the soft-sheet family — for low-creep TFM/NXT modified PTFE see /materials/modified-ptfe-low-creep.
At a Glance
Temperature Range
-200 °C to +260 °C continuous
Thickness Range
0.5 mm to 6.4 mm
Available Forms
Colours
Brands We Stock
Technical Properties
Typical values across stocked grades. Specific grade data sheets available on request.
Physical Characteristics
Density
0.85–1.70 g/cm³ (type dependent)
Tensile Strength
10–14 MPa
Compression Set
See creep relaxation: 15–40% (ASTM F38)
Compressibility
55–70% (ASTM F36)
Recovery
12–35% (ASTM F36)
Chemical Resistance
Resistant To
- Virtually all acids — concentrated HCl, H₂SO₄, HF, HNO₃ (see notRecommended for oleum and hot concentrated HNO₃)
- Virtually all alkalis and bases
- All solvents, hydrocarbons, and aromatics
- Chlorine and bromine (gaseous, at moderate pressure)
- Sodium hypochlorite up to ~12.5%
- Hydrogen peroxide up to 30% at ambient
- Steam and hot water
- Cryogenic media (liquid nitrogen, LNG)
Limited Resistance
- Glass-microsphere-filled types: strong alkalis above 85 °C may attack filler
- Concentrated hydrogen peroxide above 30% — verify case-by-case
- Hot concentrated nitric acid above ~70% — limit exposure
Not Recommended
- Oleum (fuming sulphuric acid)
- Molten alkali metals (sodium, potassium) — decompose the fluorocarbon chain
- Elemental fluorine at elevated temperature and pressure
- Interhalogen fluorinators (ClF₃, BrF₃, OF₂) at any concentration — violent reaction risk
Environmental Ratings
Flame Rating
Non-flammable. PTFE does not sustain combustion (LOI >95%)
Weather Resistance
Excellent. PTFE is inherently UV, ozone, and weather resistant
Ozone Resistance
Excellent (fully inert)
UV Resistance
Excellent, with no degradation from UV exposure
Standards & Certifications
Standards Compliance
Common Applications
- Glass-lined reactor and vessel flange gaskets
- Enamel-coated equipment sealing
- FRP (fibreglass reinforced plastic) pipe and vessel flanges
- Ceramic and porcelain flanges
- Plastic flanges (PVDF, PP, HDPE) where bolt load is limited
- Damaged, warped, or pitted metal flange faces
- Low bolt-load connections (hand-tightened or limited-torque)
- Chemical processing (aggressive acids, solvents, and oxidisers)
- Pharmaceutical and food-grade process seals
- Cryogenic service down to -200 °C
- Multi-media service where one gasket material covers the entire plant
Not Recommended For
- Not for high-pressure service. Maximum 40–83 bar depending on grade (spiral wound or CNAF better above 40 bar)
- Low recovery (12–35%) means gaskets are single-use; do not reuse after disassembly
- Lower tensile strength than virgin PTFE, so soft sheets can tear during handling
- Cold flow still occurs under sustained load, though reduced vs virgin PTFE
- Glass-microsphere-filled types have slightly reduced alkali resistance above 85 °C
- Not suited to cyclic thermal or pressure loading without retorque protocols
Available Grades
Brands we stock: KLINGER, Frenzelit, Garlock, Teadit, James Walker
Multi-Directional ePTFE (Soft-Chem Type)
Food SafePure expanded PTFE sheet with no fillers. Lowest density (~0.9 g/cm³) and highest compressibility (55–60%). Maximum chemical universality, suited to the most aggressive media where no filler compromise is acceptable.
Glass Microsphere Filled PTFE (Novaflon Type)
Food SafePTFE matrix filled with hollow glass microspheres for improved mechanical strength and creep resistance over pure ePTFE. Slightly higher density (~1.70 g/cm³). Better dimensional stability and handleability than pure foam grades.
Microcellular Layered PTFE (GYLON 3545 Type)
Soft microcellular outer layers bonded to a rigid PTFE core. Best creep resistance of the foam family (15% relaxation) and highest pressure rating of the foam group. Easiest to handle due to the rigid core.
Related Resources
Expanded PTFE (ePTFE)
Compare with standard ePTFE gasket sheet, which is denser and suited to higher bolt-load joints.
Virgin PTFE Sheet
Solid virgin PTFE — less compressible, needs higher bolt load, but better creep performance.
Filled PTFE Sheet
Glass, carbon, and bronze filled PTFE for maximum mechanical strength under load.
Chemical Compatibility
Check PTFE compatibility with your process media.
Related Materials
Need PTFE Foam Sheet?
We supply ptfe foam sheet in sheet, roll, and custom die-cut forms. Contact our team for pricing, data sheets, or technical assistance.
Disclaimer
This resource is provided for general engineering reference only and does not constitute professional advice, specification, or guarantee of performance. Actual results depend on specific application conditions. Universal Gaskets Pty Ltd accepts no responsibility or liability for decisions made based on this information. For full terms, see our Terms & Conditions.