| HS Code | 450507 |
| Density | 1.04 g/cm³ |
| Water Absorption 24h | 1.7 % |
| Tensile Strength | 44 MPa |
| Elongation At Break | 250 % |
| Tensile Modulus | 1.00 GPa |
| Flexural Modulus | 900 MPa |
| Izod Impact Notched | 1500 J/m |
| Melting Point | 185 °C |
| Glass Transition Temperature | 60 °C |
| Brittleness Temperature | -60 °C |
| Heat Deflection Temperature 0 45 Mpa | 52 °C |
| Shore Hardness | 55 D |
| Volume Resistivity | 1.0e+13 ohm·cm |
| Dielectric Strength | 20 kV/mm |
| Dielectric Constant | 3.10 |
As an accredited Overview of materials for Nylon 11, Cable Sheathing Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Nylon 11 cable sheathing grade is packaged in 25 kg moisture-proof sealed bags, palletized and shrink-wrapped for safe transport. |
| Container Loading (20′ FCL) | One 20′ FCL of Nylon 11 cable sheathing grade, packed in sealed bags on pallets, maximizes capacity safely. |
| Shipping | Nylon 11 cable sheathing grade ships as non-hazardous polymer pellets. Use dry, sealed packaging to prevent moisture absorption. Store away from heat sources and direct sunlight. No special transport restrictions, but avoid excessive mechanical stress during handling. Ensure proper labeling and documentation for industrial shipment. |
| Storage | Store Nylon 11 cable sheathing grade in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and UV exposure. Keep containers tightly sealed to prevent moisture absorption, as the material is hygroscopic. Maintain moderate humidity and avoid prolonged storage. Use within recommended shelf life for optimal mechanical and cable performance. |
| Shelf Life | Stored properly in dry, cool, dark conditions, Nylon 11 cable sheathing grade typically has an indefinite shelf life. |
In automotive chassis cable jacket extrusion where the sheathing must survive underbody stone impingement and road salt spray, PA11 cable sheathing grade is processed after desiccant drying at 80–90°C for 4–6 h to a pellet moisture below 0.08 wt%. A single-screw extruder with L/D 24:1–30:1 and compression ratio 2.5:1–3.0:1 is used. Barrel zones are set from 190°C in the feed zone to 220°C in the metering zone. The crosshead die is held at 205–220°C. The compound incorporates a carbon black masterbatch at 2–3 wt% for UV stabilization and a copper halide heat stabilizer at 0.2–0.5 wt%. The jacket is applied by pressure tooling over PVC or XLPE primary insulation at wall thicknesses from 0.6 mm to 1.2 mm. Tensile elongation after extrusion is checked to ISO 527-2 and normally exceeds 250%. Abrasion resistance is tested under the needle abrasion method of ISO 6722-1:2013. Cold impact is checked by low-temperature winding at −40°C. The jacket appears on heavy-duty truck ABS/EBS sensor cables and engine compartment harnesses where diesel, brake fluid and glycol exposure requires the sheath to retain tensile strength after heat aging at 100°C for 1,000 h. Ambient handling above 60% RH requires a closed hopper with dried air purge to prevent moisture regain before extrusion.
Railway bogie jumper cables and coupler control cables use PA11 when the jacket must survive repeated flexing, stone impact, and fuel splash. Unmodified PA11 has a limiting oxygen index near 22–23% and requires a flame-retardant package before the assembly can meet rolling-stock fire codes. Commercial FR-PA11 cable grades typically incorporate a phosphorus–nitrogen masterbatch at 12–18 wt%. This loading commonly achieves V-0 at 3.2 mm thickness under UL 94. At 1.6 mm wall thickness the same formulation may drop to V-2. Flame-retardant masterbatches are predried at 80°C for 4 h before extrusion. Low shear zones are maintained because phosphorus–nitrogen synergists degrade if melt temperature exceeds 230°C. The jacket is pressure-extruded onto XLPE primary insulation through a crosshead die with an inner tube telescoping into the head to prevent weld-line formation.
| Standard | Clause or test | PA11 jacket configuration |
|---|---|---|
| EN 45545-2 | R23/R24, HL1–HL3 | FR PA11, 3.2 mm wall, V-0 under UL 94 |
| EN 50264-1 | General requirements for railway cables | Crosshead-extruded PA11 over XLPE core |
| UL 94 | Vertical burn, 3.2 mm | V-0 at 3.2 mm, V-2 at 1.6 mm |
| NFPA 130 | Smoke and heat release in tunnel applications | Low-smoke FR masterbatch required for enclosed tunnel routing |
The limiting constraint is smoke density. A PA11 jacket that achieves the flame spread index under EN 45545-2 R23/R24 may still require a low-smoke additive or a composite design when the cable is routed through enclosed tunnel spaces because PA11 is not inherently a low-smoke material. Electrical and mechanical testing beyond fire performance is covered by EN 50264-1. Final cable assemblies are installed as bogie jumpers, coupler control links, and door loop connections on rolling stock.
Offshore downhole instrument cable jackets are extruded from PA11 cable sheathing grade when the jacket must withstand long-term contact with methanol, crude oil, and water-based drilling fluid at moderate temperatures. The formulation is modified with an external plasticizer such as n-butylbenzene sulfonamide at 6–10 phr to preserve low-temperature flexibility during reeling operations at −30°C. The extruder is configured with a 24:1 L/D low-shear screw and a crosshead pressure die set at 210–225°C. The sheath is applied over aramid or braided steel wire subcable cores. Wall thickness is maintained between 1.0 mm and 2.0 mm. Inline laser micrometers hold jacketing concentricity above 90%. Hydrolysis resistance is evaluated by comparing tensile strength before and after immersion in water at 80°C for 1,000 h under ISO 1817. Fluid resistance is assessed in methanol and ASTM reference oil IRM 903 under ISO 1817 or ASTM D471. Compliance for subsea control lines references API 17E and ISO 13628-5. PA11 should not be specified where continuous exposure to sour gas or temperatures above 90°C dominates the service profile. Finished jackets serve downhole instrumentation, subsea wellhead monitoring, and surface control line jumpers.
Offshore wind pitch and yaw cable carriers subject jackets to mechanical flexing, salt fog, and rapid temperature cycling. PA11 is used in this narrow application window because its equilibrium moisture at 50% RH is approximately 0.7–0.9 wt%. This limits dimensional change and loss of stiffness in cold weather. The compound contains 2–3 wt% carbon black masterbatch and a hindered amine light stabilizer package. The jacket is extruded onto flexible stranded copper conductors at a wall thickness of 1.2–2.0 mm. Crosshead die temperature is held at 205–215°C. After extrusion, samples are subjected to 1,000 h salt spray per ISO 9227 followed by low-temperature bending at −40°C. The acceptance threshold commonly applied is retention of more than 80% of original tensile elongation. UV resistance is verified after 500 h of xenon arc exposure under ISO 4892-2. PA11 is not necessarily specified for tower interior low-smoke halogen-free circuits because the jacket priority in pitch and yaw service is mechanical endurance and salt fog performance, not the fire-performance class. Finished cables feed pitch motor power circuits, yaw encoder feedback, and turbine control cabinet jumpers.
Continuous flexing in drag chains produces jacket wear against carrier dividers and adjacent conduits. PA11 occupies a small formulation space in this sector where ester-based thermoplastic polyurethane would undergo acid hydrolysis from contaminated hydraulic fluid or zinc stearate dust. The PA11 jacket is extruded onto shielded servo cores at a wall thickness of 0.8–1.2 mm. A slip additive masterbatch, often PTFE-loaded, is used at 5–10 wt% to reduce drag chain friction. The screw configuration is a 24:1 L/D general-purpose screw with no high-shear mixing elements because the PTFE masterbatch can induce agglomerates if overworked. Crosshead melt temperature is 210–225°C. Inline spark testing at 2.5 kV monitors jacket integrity. Flexing performance is evaluated under continuous bend cycles in a cable carrier with a bend radius of 7–10 times the cable diameter. Abrasion is measured by weight loss after 1,000 cycles on a Taber abraser following ASTM D4060. Finished jackets are used on servo motor power cables, encoder feedback cables, and robot dress packs where repeated torsion, oil mist, and metal swarf are present. Published property data for this exact cable configuration is limited, so qualification is normally performed on the complete cable assembly rather than on the jacket compound alone.
Tactical field cables require a jacket that resists diesel, JP-8, and hydraulic fluids while remaining flexible after long storage in wet environments. PA11 cable sheathing grade is formulated with external plasticizer below 8 phr because higher plasticizer levels can be extracted by diesel and then shorten low-temperature flexibility. A heat-stabilized grade is selected for cable jackets used in arid and tropical conditions. The jacket is extruded onto braided shield or screened conductor bundles at a wall thickness of 1.0–1.5 mm. Crosshead die temperature is 205–215°C and the line speed is set to maintain a die-to-outer diameter draw ratio below 1.1:1 so that anisotropic shrinkage does not cause long-term stress cracking. Hardness is controlled to Shore D 58–65 under ISO 868. Fuel resistance is tested by immersion in ASTM reference fuel C under ASTM D471 for 70 h at 23°C, with tensile strength retention above 70% and elongation retention above 60%. Hydrolytic stability is checked in water at 80°C for 1,000 h. The jacket is not rated for continuous immersion in ethylene glycol methyl ether-based deicing fluids at elevated temperature. Finished jackets serve field-deployable power distribution cables and communication cable jackets.
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Polyamide 11 (PA11) cable sheathing grade is a semi-crystalline extrusion polyamide obtained from 11-aminoundecanoic acid, with eleven methylene units separating amide groups in the polymer backbone. The sheathing compounds are supplied as natural, black, or color-matched formulations and are typically plasticized or semi-flexible grades with Shore D hardness values of 62–76 depending on plasticizer content. An industrial reference is Rilsan BESNO P40 TL, a cable sheathing grade used for thin-wall jackets in oil and gas control circuits. The material is selected when the jacket must withstand hydrocarbons, mechanical abrasion, moisture cycling, and low-temperature installation without the halogen acid gas generation associated with PVC.
Typical melt volume-flow rate for cable sheathing extrusion grades is 8–25 cm³/10 min at 235 °C and 2.16 kg load according to ISO 1133-1. This range supports thin-wall tube and cable coating without excessive die swell. The product is distinguished from generic PA11 molding grades by a narrower viscosity window, lower gel content, and additive packages for UV stability and processing. In field use, PA11 cable sheathing is specified for offshore umbilicals, subsea control cables, railway rolling-stock jumpers, automotive sensor harnesses, and fiber-optic protective jackets where HDPE lacks heat resistance and PA12 may lack stiffness or supplier-approved low-temperature impact data.
Material specifications are commonly based on supplier datasheets that reference ISO 1183-1 for density, ISO 527-2 for tensile properties, ISO 178 for flexural modulus, ISO 868 for hardness, ISO 179-1 for impact, and IEC 60243-1 for dielectric strength. Cable-level specifications may require additional testing under IEC 60332-1-2, EN 50265-2-1, UL 2556 VW-1, or equivalent. The base PA11 resin is halogen-free and generally complies with RoHS Directive 2011/65/EU and REACH Regulation (EC) No 1907/2006, but final compound compliance depends on color masterbatch and processing stabilizers.
At storage relative humidities above 60%, hopper drying is imposed at 80–90 °C for 4–6 h with dehumidified air to reduce moisture to below 0.1% before melt processing. Residual moisture above 0.08% causes hydrolysis-induced melt fracture, surface roughness, and void formation on single-screw extrusion lines. The extruder is typically a 25:1 or 30:1 L/D single-screw machine with a compression ratio of 2.5:1 to 3.5:1 and a screen pack at 100–150 μm to remove gel contamination. Barrel profiles of 200–230 °C from feed to die are used, with melt temperature held at 220–240 °C at the crosshead. From production-scale extrusion of a 1.0–1.2 mm jacket over 2.5 mm² copper conductor, stable operation is obtained at melt pressures of 18–25 MPa, screw speeds of 25–40 min⁻¹ on a 60 mm extruder, and drawdown ratios of 2.0:1 to 3.0:1. Die land length is set at 10–15 times the annulus gap to minimize frozen-in orientation and eccentricity. Water trough temperatures of 20–40 °C are used after the die; rapid quenching below 15 °C reduces spherulite size but can freeze in surface defects on thick sections.
Batch-to-batch variation in melt viscosity is controlled by the supplier to approximately ±10% of nominal MVR. Deviation outside this range produces wall-thickness oscillation, especially when the extruder is run near the lower melt-pressure limit. The use of a gear pump is not mandatory but is specified when jacket thickness tolerance is below ±0.05 mm. Processors should avoid hold-up times longer than 20 min at melt temperatures above 230 °C because viscosity drift and gel speck formation may occur, particularly in black grades with high carbon black loading.
In offshore umbilical and subsea control cable applications, PA11 sheathing grade is applied at wall thicknesses of 1.5–3.0 mm over twisted pairs or hydraulic tubes. The jacket must survive torsional and tensile loads during laying and service; notched Charpy impact energy at -30 °C is typically specified at or above 6 kJ/m² to avoid brittle cracking on reel deployment. In automotive harness and rail jumper applications, abrasion resistance is evaluated under ISO 5470-1 or equivalent sand-slurry methods, and PA11 grades show lower mass loss than PVC and HDPE at comparable hardness. In fiber-optic buffer tubes, the PA11 jacket is selected for hydrocarbon resistance and dimensional stability, with a maximum ovality of 0.1 mm after post-extrusion annealing and moisture conditioning at 50% RH, 23 °C for 48 h.
Volume resistivity is measured according to IEC 62631-3-1 and is generally reported in the range 1013–1015 Ω·cm at 23 °C and 50% RH. Because the water saturation is limited to 1.8–2.0% by ISO 62, insulation resistance after humidity cycling is more stable than that of PA6 or PA66, which can absorb more than 8% water and lose several orders of magnitude in surface resistivity. Dielectric strength on a 1 mm compression-moulded specimen is typically 25–35 kV/mm per IEC 60243-1; the value depends on electrode geometry and specimen conditioning. Abrasion resistance is assessed by ISO 5470-1 Taber procedures or cable-specific drum abrasion methods, and PA11 sheathing grades are formulated with sufficient molecular weight and plasticizer balance to resist cut-through during cable pulling.
Chemical resistance of PA11 cable sheathing is based on the hydrocarbon-resistant character of the polyamide 11 backbone. Immersion in reference fuel C at 60 °C for 500 h generally yields tensile strength retention above 80% and dimensional change below 2%; immersion in seawater at 60 °C is not aggressive to the polymer backbone, but tensile modulus may decline as absorbed water plasticizes the amorphous phase. Concentrated mineral acids, phenols, formic acid, and some oxidizing chemicals degrade the material at elevated temperature and are not recommended for continuous service. Long-term exposure to strong alkaline solutions can also reduce surface gloss and promote microcracking on stressed jackets, particularly at temperatures above 50 °C.
| Property | Test method | Reported range |
|---|---|---|
| Density | ISO 1183-1 | 1.03–1.05 g/cm³ |
| Melting temperature | ISO 11357-3 | 183–189 °C |
| Tensile stress at break | ISO 527-2 | 50–60 MPa |
| Nominal strain at break | ISO 527-2 | >200 % |
| Flexural modulus | ISO 178 | 1000–1300 MPa |
| Shore D hardness | ISO 868 | 70–76 |
| Notched Charpy impact at 23 °C | ISO 179-1/1eA | 8–12 kJ/m² |
| Water absorption saturation, water at 23 °C | ISO 62 | 1.8–2.0 % |
| Volume resistivity | IEC 62631-3-1 / ASTM D257 | 1013–1015 Ω·cm |
| Dielectric strength, 1 mm specimen | IEC 60243-1 | 25–35 kV/mm |
For systematic material selection, PA12 extrusion sheathing grades provide lower density and lower flexural modulus, with a melting point approximately 7–10 K lower than PA11. HDPE jacketing compounds offer lower cost and negligible water absorption but are not specified for continuous service above 70–80 °C under mechanical load. PVC compounds provide adjustable hardness and low cost but can generate acidic combustion gases and show reduced low-temperature ductility unless heavily plasticized. Published data for specific cable constructions under combined thermal and chemical aging is limited; qualification must be based on finished cable testing rather than base polymer comparisons.
| Property | PA11 sheathing grade | PA12 extrusion grade | HDPE jacketing compound |
|---|---|---|---|
| Density (ISO 1183-1) | 1.03–1.05 g/cm³ | 1.01–1.02 g/cm³ | 0.94–0.96 g/cm³ |
| Melting temperature (ISO 11357-3) | 183–189 °C | 176–180 °C | 125–135 °C |
| Tensile stress at break (ISO 527-2) | 50–60 MPa | 45–50 MPa | 25–35 MPa |
| Flexural modulus (ISO 178) | 1000–1300 MPa | 700–900 MPa | 800–1200 MPa |
| Water absorption saturation (ISO 62) | 1.8–2.0 % | 1.0–1.5 % | <0.1 % |
| Dielectric strength, 1 mm specimen (IEC 60243-1) | 25–35 kV/mm | 25–35 kV/mm | 20–30 kV/mm |
When sheathing is applied to medium-voltage or high-voltage cable accessories, dimensional stability under humidity cycling can dominate material selection. PA11 absorbs approximately 1.8–2.0% water at saturation, which is substantially lower than PA6 or PA66 and allows the jacket to retain over 70% of its dry flexural modulus after moisture conditioning. The water-induced plasticization is reversible; after drying at 80 °C in vacuum, mechanical stiffness recovers, although repeated moisture cycling can alter residual stress distribution in thick extruded sections. For wet cable trenches or ducts with standing water, PA11 sheathing does not undergo the brittle hydrolytic degradation seen in polyesters, but the reduction in glass transition temperature due to absorbed water must be considered when impact loads occur below -20 °C.
In high-voltage accessories, the absolute moisture content is relevant because absorbed water increases dielectric loss and reduces surface resistivity. Conditioning at 50% RH and 23 °C for 48 h typically results in surface resistivity above 1012 Ω. The product is not recommended for direct burial without an additional moisture barrier if the specification requires insulation resistance stability after immersion for more than 1000 h; in such cases the cable construction, not the base PA11 grade, must be qualified.
Thermogravimetric analysis under nitrogen shows onset of mass loss near 350 °C, but melt processing is limited by oxidative degradation and viscosity drift above 250 °C. At melt temperatures above 250 °C, chain scission and oxidation lead to yellowing, increased MVR, and gel specks in black grades. Oxygen exclusion is not complete in single-screw extrusion, so barrel temperatures should not exceed 250 °C, and start-up after shutdown should be purged with fresh resin rather than prolonged heating. Post-extrusion crystallization occurs rapidly; line speeds and cooling bath length should be arranged so the jacket enters the haul-off at surface temperatures below 60 °C to prevent ovality and shrinkback.
For applications requiring flame retardance, unfilled PA11 sheathing grade is not inherently self-extinguishing; UL 94 classification is generally HB. Flame-retardant cable jackets must be compounded with specific halogen-free or halogenated FR systems, and the final cable must be tested to IEC 60332-1-2, EN 50265-2-1, UL 2556 VW-1, or equivalent, because the base resin alone cannot guarantee fire performance. Processing of PA11 over copper conductors does not usually require adhesion promoters, but surface contamination from drawing lubricants must be removed by in-line preheating or plasma treatment to prevent jacket slippage. The material is not recommended for continuous exposure to concentrated formic acid, phenols, or concentrated mineral acids at temperatures above 40 °C. Finished cable specifications should verify compound-specific compliance for RoHS Directive 2011/65/EU and REACH Regulation (EC) No 1907/2006 when color concentrates or processing aids are added.
