Reinforced PTFE
Reinforced PTFE
Reinforced PTFE Raw Material Properties (Filled PTFE Composite Resin)
1. Basic Definition
Reinforced (filled) PTFE raw material is a composite powder blend: virgin PTFE resin + rigid reinforcing fillers (glass fiber, carbon, graphite, bronze, MoS₂, etc.). Fillers overcome pure PTFE’s core weaknesses: severe creep, low wear resistance, poor rigidity & thermal conductivity, while retaining most of PTFE’s inherent superior chemical & thermal performance.
2. Universal Base Properties (All Reinforced PTFE Grades Retain)
Thermal Properties
- Continuous service temperature: -200 ℃ ~ +260 ℃; short-term peak 300 ℃
- No melting flow (processing only by compression molding / paste extrusion); high heat decomposition resistance
- Low linear thermal expansion (much lower than virgin PTFE, better dimensional stability)Röchling
Chemical Inertness
- Resist all strong acids, alkalis, solvents, oxidants, aqua regia
- Only attacked by molten alkali metals, high-temperature fluorine gas
- Exception: glass-filled PTFE eroded by strong alkali & hydrofluoric acid (HF)
Surface & Anti-Adhesion
- Ultra-low friction coefficient (0.02–0.12; graphite/MoS₂ filled grades have the lowest μ)
- Non-stick, self-lubricating, no surface adhesion
- Excellent weathering, UV & ozone resistance
Electrical Baseline
- Dielectric constant ≈2.1, low dielectric loss
- Pure glass/graphite filled: excellent insulator; carbon/bronze filled: semi-conductive / conductive, anti-static capability
3. Core Improved Mechanical Properties vs Virgin PTFE
Virgin PTFE is soft, prone to cold flow (creep) under sustained load. Reinforcement delivers these key upgrades:
- Creep resistance: 30%–80% reduction in permanent deformation under compressive load
- Compressive modulus & hardness: 2–3× stiffer, higher ball indentation hardness
- Wear life: Up to 1000× longer service life for sliding friction parts
- Dimensional stability: Less shrinkage/expansion with temperature & load
- PV limit (pressure×velocity): Higher dynamic load bearing capacity for bearings & seals
- Drawback trade-off: Elongation at break drops sharply (virgin PTFE ≈300–400%; reinforced PTFE only 50–200%)
4. Property Breakdown by Common Reinforcement Fillers
4.1 Glass Fiber Filled PTFE (5% /15% /25% GF, most general-purpose grade)
- Strengths: Low cost, best creep resistance, retains excellent insulation, balanced wear performance
- Properties: S.G. 2.10–2.25; off-white color; friction slightly higher than graphite grades
- Limitations: Poor resistance to HF & concentrated strong alkali; mild abrasion to soft mating shafts
- Typical uses: General seals, gaskets, low-load bearings, electrical insulating components
4.2 Carbon / Graphite Filled PTFE (10–35% carbon/graphite)
- Strengths: Outstanding wear resistance, high thermal conductivity, self-lubricating, anti-static/conductive, fully resistant to HF & strong alkali
- Properties: Black/grey; volume resistivity adjustable (10⁴–10¹² Ω·cm); high PV value for dry/wet sliding
- Limitations: Electrical insulation lost; slightly higher abrasion on soft metal counterparts
- Typical uses: Hydraulic piston rings, compressor seals, water pump bearings, anti-static electronic parts大金氟化工...
4.3 Bronze Powder Filled PTFE (40–60% bronze, highest mechanical grade)
- Strengths: Highest compressive strength, maximum thermal conductivity, supreme wear resistance for heavy loads, excellent damping
- Properties: Dark brown; S.G. 2.9–4.0 (much denser); semi-conductive
- Limitations: Poor chemical resistance to acids; heavy weight; not insulating
- Typical uses: Heavy-duty hydraulic seals, high-load bearing liners, gear sliding pads, high-temperature friction components
4.4 MoS₂ + Glass Hybrid Filled PTFE (15%GF + 5% MoS₂)
- Strengths: Lowest friction coefficient among glass-filled grades, improved dry-running lubricity
- Limitations: MoS₂ oxidizes above 200 ℃, unsuitable for high-temperature air environments
- Typical uses: Low-speed, light-load precision sliding guides, food machinery bushings
5. Standard Physical & Mechanical Reference Data (Typical Values)
| Property | Test Standard | Virgin PTFE | 25% Glass PTFE | 25% Carbon PTFE | 40% Bronze PTFE |
|---|---|---|---|---|---|
| Specific Gravity | ASTM D792 | 2.15 | 2.20 | 2.10 | 3.00 |
| Tensile Strength (MPa) | ASTM D4894 | 20–28 | 22–32 | 25–35 | 28–45 |
| Elongation at Break (%) | ASTM D4894 | 300–400 | 80–150 | 70–120 | 50–90 |
| Ball Hardness (MPa) | ISO 2039 | 28–32 | 42–48 | 43–49 | 55–65 |
| Compressive Creep Deformation (%) (24h, 14MPa) | ASTM D621 | 18–25 | 5–8 | 6–9 | 3–5 |
| Coefficient of Friction (dry steel) | ASTM D1894 | 0.04–0.06 | 0.07–0.10 | 0.05–0.08 | 0.08–0.12 |
| Thermal Conductivity (W/m·K) | ASTM C177 | 0.25 | 0.35 | 0.60 | 1.20 |
| Volume Resistivity (Ω·cm) | ASTM D257 | >10¹⁷ | >10¹⁶ | 10³–10⁶ | 10²–10⁴ |
6.Typical Applications of Reinforced PTFE
Reinforced PTFE is the preferred material for manufacturing high-performance sealing and wear components used in demanding industries:
- Oil & Gas: valve seals, gaskets, downhole components, pipeline sealing parts
- Hydraulic Systems: piston seals, rod seals, bearings, wear rings, cylinder components
- Automotive: engine seals, transmission parts, fuel system components, bearing bushes
- Fluid Equipment: pump seals, valve seats, thrust washers, sliding components
- General Machinery: high-load bearings, wear plates, custom mechanical parts
TOPSEALS uses high-quality reinforced PTFE compounds to produce precision sealing components with stable performance, long service life, and reliable operation under extreme pressure, temperature, and load conditions.
