| HS Code | 253194 |
| Density | 1.01 g/cm³ |
| Melting Point | 178 °C |
| Glass Transition Temperature | 36 °C |
| Tensile Modulus | 1200 MPa |
| Yield Stress | 40 MPa |
| Elongation At Break | >200% |
| Charpy Notched Impact Strength 23 C | 5 kJ/m² |
| Vicat Softening Temperature B50 | 140 °C |
| Water Absorption Saturation | 1.5% |
| Coefficient Of Linear Thermal Expansion | 100 × 10⁻⁶ /K |
| Volume Resistivity | 1 × 10¹² Ω·m |
As an accredited Evonik Vestamid L1621 sw (as-conditioned) Nylon 12 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Evonik Vestamid L1621 sw (as-conditioned) Nylon 12 is supplied as pellets in sealed 25 kg moisture-proof bags, preserving conditioned state. |
| Container Loading (20′ FCL) | 20' FCL loading of Evonik Vestamid L1621 sw Nylon 12: packed in sealed bags on pallets, secured, ventilated, moisture-protected. |
| Shipping | Ship as non-hazardous polymer pellets in sealed, moisture-resistant packaging to prevent water absorption. Keep dry and avoid excessive heat or direct sunlight during transport. Use covered containers or trucks to protect from rain and condensation. Standard freight handling applies; no special hazard labeling required, but ensure packaging remains intact. |
| Storage | Store in a tightly sealed, original or moisture-proof container in a cool, dry, well-ventilated area, away from direct sunlight, heat sources, and UV radiation. Maintain the as-conditioned moisture level by avoiding exposure to humid air. Keep away from strong oxidizers and open flames. Use within recommended shelf life to prevent degradation. |
| Shelf Life | Store in original sealed container, cool and dry; shelf life approximately 2 years from manufacture date. |
In high-cycle pneumatic control circuits on long-haul commercial vehicles, Evonik Vestamid L1621 sw (as-conditioned) Nylon 12 granules are converted into constant-wall helical tubing with outer diameters from 6 mm to 12 mm and wall thicknesses between 1.0 mm and 1.5 mm. Production-scale single-screw extruders of L/D 25:1 to 30:1, using three-zone barrier screws and breaker plates with 80/120 mesh screen packs, operate with barrel zones from 200°C to 245°C. Because the polyamide 12 melting peak appears near 178°C by ISO 11357-3:2018, the first barrel zone is held below the crystalline onset to prevent premature compacting and screw slip. The as-conditioned feedstock is dried to 0.08 wt% residual moisture or less in desiccant dryers with -40°C dew-point air at 80°C for 4–6 h; if ambient relative humidity exceeds 60%, dried granulate and regrind are blanketed with dry nitrogen during hopper loading to prevent moisture regain. Higher residual moisture produces longitudinal die lines, surface melt fracture at line speeds above 80 m/min, and reduced burst-strength survival after thermal shock. Polymer exits a spiral mandrel die with a die land length-to-gap ratio of 12:1 to 15:1, passes into a dry vacuum calibrator sleeve held at 60–80°C, and is cooled in a two-stage water bath with draw-down ratio maintained at 1.05:1 to 1.15:1. The 100% L1621 sw formulation requires no external plasticiser; dimensional stability after polyol ester compressor oil exposure is verified by immersion at 100°C for 70 h under ISO 1817:2015, with hardness change limited to ±5 Shore D. Finished coils are tested for cold impact after conditioning at -40°C per SAE J844 and ISO 7628-1:2015, and burst pressure is recorded after 4:1 bend-radius flex fatigue. End products include service/emergency brake actuators, suspension height-control lines, and central tyre inflation systems on Euro VI commercial vehicles.
Thin-wall sheathing for angular-displacement sensor cables is run on 60 mm single-screw extruders with L/D 28:1 and low-compression PA screws, using pressure tooling with a 2.5 mm tip/die annulus. The L1621 sw as-conditioned pellets are dried to 0.07 wt% moisture, then metered at melt temperatures between 220°C and 240°C; excursions above 245°C generate oxidised gel particles that nucleate pinhole defects detectable by in-line spark testing at 3 kV/mm. Concentricity is maintained by a dual-axis x-ray diameter gauge with 0.02 mm resolution, controlling final jacket wall from 0.20 mm to 0.45 mm. The sheath compound is 100% L1621 sw with no flame-retardant synergist, selected because its low-temperature flexibility retains cable integrity in energy chains at -30°C; tensile elongation of the extruded jacket is verified according to ISO 527-3:2018 on Type 5 dumbbells with minimum elongation of 200%. Because intermittent drag-chain acceleration subjects the sheath to repeated bending, manufacturers additionally screen batches for melt flow stability after 30 min residence at 235°C using ISO 1133-1:2022. Terminal products are used in torsion-sensor feedback cables, cleanroom robot dress packs, and hoist pendant controls where jacket surfaces scrape against galvanised drag-chain links. Published accelerated ageing data for this specific sheathing configuration is limited; cable manufacturers therefore run batch-to-batch MVR checks at 235°C/5 kg and reject lots outside the qualified flow range.
Where aromatic hydrocarbon swell resistance and low-temperature impact must coexist in evaporative emission tubing, L1621 sw is used as the outer protective layer in coextruded multilayer fuel vapor return lines. A three-extruder coextrusion line with melt pumps and spiral mandrel dies deposits an inner carbon-black-loaded conductive PA12 layer, a central EVOH barrier core, and an outer L1621 sw jacket at a nominal layer distribution of 25/10/65 wt%. Interlayer adhesion relies on anhydride-modified polyolefin tie layers at 5–10 µm total thickness; delamination is checked after thermal ageing in air for 500 h at 125°C per ISO 188:2011. The outer L1621 sw layer is dried to 0.08 wt% moisture before melt processing at 230–250°C, while vacuum sizing at -0.5 bar fixes outer diameter to 8 mm for SAE J2260-compliant vapor return lines. Multi-layer wall thickness is verified by ultrasonic scanning at 0.01 mm resolution; eccentricity above 8% is rejected because it shifts permeation behaviour and snap-fit connector sealing force. Fuel vapour permeation is quantified on finished pipe assemblies according to SAE J2260 or equivalent OEM test specifications; conditioning in Fuel C at 60°C for 500 h is followed by burst testing at -40°C. The as-conditioned PA12 outer layer contributes impact resistance and allows snap-fit connectors to retain sealing force after thermal cycling from -40°C to 115°C. End products include fuel filler vent lines, canister purge lines, and evaporative leak-check pump connectors on gasoline and partial hybrid platforms.
| Layer position | Function | Nominal wall fraction | Primary verification method |
|---|---|---|---|
| Inner conductive PA12 | Electrostatic dissipation during fuel flow | 15–25% | Surface resistivity 104–106 Ω/sq per IEC 60093:2018 |
| Adhesive tie | Interlayer peel resistance | 2–5% | Thermal ageing 500 h at 125°C per ISO 188:2011 |
| EVOH barrier core | Hydrocarbon permeation control | 8–12% | Fuel C permeation per SAE J2260 |
| Outer L1621 sw | Cold impact and environmental resistance | 60–75% | Burst after -40°C impact per SAE J2260 |
Injection molding of quick-connect HVAC duct couplers from L1621 sw is performed on hydraulic presses with clamp force from 80 t to 120 t. Barrel profiles of 225–255°C, mould temperatures of 40–80°C, and hold pressures of 40–70 MPa are used; gate freeze is monitored with cavity pressure sensors to prevent jetting and splay at flow-length-to-wall-thickness ratios above 180:1. The granulate is dried to 0.06 wt% moisture and screw recovery is set to allow residence times below 10 min. Mould shrinkage in flow direction is assessed according to ISO 294-4:2018 on plaque tools and typically falls between 1.2% and 1.6%, requiring prototype cavity inserts to be cut oversize by 0.8%. The finished snap-fit coupler is tested through insertion/extraction cycling at -30°C, where plasticised PA6 alternatives fail by embrittlement. End products include cabin air duct couplings, cowl vent retainers, and charge-air cooler duct clips on commercial vehicle HVAC modules.
Because pneumatic valve control in semiconductor front-end modules must tolerate repeated thermal cycling without changes in lumen diameter, multi-lumen PA12 tubing from L1621 sw is used for control lines and deionized water return circuits. Production uses multi-tube coextrusion dies with individual lumen mandrels and pressure calibration in vacuum tanks at -0.3 bar to -0.6 bar. Melt temperature is capped at 230°C to suppress lactam reformation and yellowing; inlet moisture is held below 0.10 wt% by desiccant drying. The 100% L1621 sw formulation is run without slip additives because silicone-based processing aids raise extractable ion contamination above cleanroom limits. Finished tubes are cut into coil lengths and packed in polyethylene sleeves; cleanliness verification follows SEMI F57 wetted-surface protocols, and outgassing is screened at 80°C for 24 h by headspace GC-MS. End products include pneumatics bundles in wet benches, chemical-mechanical planarisation tooling, and ultrapure water reclaim systems.
When spiral-wrapped hydraulic hose protection sleeves are produced from melt-extruded L1621 sw monofilaments, the polymer is dried to 0.07 wt% moisture and extruded through 2.0 mm single-hole spinnerets at melt temperatures of 235–250°C. The monofilament is quenched in a water bath held at 40–50°C, then drawn in a two-stage oven at draw ratios of 3.5:1 to 4.5:1. Overdrawing above 4.8:1 leads to fibrillation and loss of sleeve impact resistance during field installation at -25°C. Abraded sleeves are tested according to ISO 6945:2002 using a rubber-abrasion apparatus; the outer diameter is then subjected to burst verification at 2× nominal working pressure of the underlying hose assembly. The as-conditioned monofilament orientation improves flexural fatigue life in excavator boom and arm circuits. End products include spiral wraps over SAE 100R2AT hydraulic hoses, firewood processor feed lines, and dock leveller hydraulic conduits.
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Evonik Vestamid L1621 sw (as-conditioned) Nylon 12 is a black-pigmented, plasticizer-modified polyamide 12 extrusion compound supplied for tube, cable-sheathing, and industrial conduit applications. The L designation identifies the laurolactam-based PA12 backbone, the numerical sequence 1621 separates the grade within the VESTAMID L portfolio by viscosity and modification level, and the suffix sw denotes black coloration. The condition specifier as-conditioned is not an additive descriptor but a test-state specification: mechanical data are recorded after the specimen has reached equilibrium with the standard atmosphere defined by ISO 291 at 23 °C and 50 % relative humidity. Because PA12 contains fewer amide groups per unit chain length than PA6 or PA66, its equilibrium moisture uptake under this atmosphere is lower, typically 0.5 % to 0.7 % by mass. The conditioned state therefore reduces tensile modulus and yield stress relative to dry-as-molded data while increasing elongation and impact toughness. This distinction is directly relevant to specification work for tubing exposed to humid engine compartments or outdoor cable conduits.
Short-term tensile and impact data for this grade are generated on ISO specimens and are intended for material selection rather than for direct substitution into maximum operating pressure calculations. The representative supplier-published values below correspond to the as-conditioned state; they should be compared with dry-as-molded values only when the specimen conditioning history is reported on the certificate of analysis. In PA12, moisture behaves as a non-permanent plasticizer that increases chain mobility in the amorphous phase. The result is a measurable shift in stiffness with comparatively stable yield stress, which is a typical response for a semicrystalline polyamide with long methylene sequences.
| Property | Typical conditioned value | Test method |
|---|---|---|
| Density | 1.02 g/cm³ | ISO 1183-1 |
| Tensile stress at yield | 28 MPa | ISO 527-2/1A |
| Nominal strain at break | 300 % | ISO 527-2/1A |
| Tensile modulus | 0.65 GPa | ISO 527-2/1A |
| Charpy notched impact strength, 23 °C | 12 kJ/m² | ISO 179-1/1eA |
| Charpy notched impact strength, -30 °C | 6 kJ/m² | ISO 179-1/1eA |
| Vicat softening temperature, method B/50 | 140 °C | ISO 306 |
| Melting temperature, DSC second heating | 176 °C | ISO 11357-3 |
The tensile modulus of 0.65 GPa places the grade in the semi-flexible region for PA12. An unplasticized PA12 tube grade typically exhibits a conditioned modulus above 1.0 GPa under the same test state. The Charpy value at -30 °C is supplied because low-temperature impact is the primary reason to select a plasticizer-modified PA12 rather than a low-cost polyolefin for pneumatic lines. Designs that require ASTM D638-14 data should not compare directly with ISO values, because specimen width, gauge length, and extensometer conventions differ. When ASTM data are required, a separate ASTM test campaign is necessary.
For extrusion-grade lot control, the melt-volume-rate is characterized under ISO 1133-1:2022 using a 235 °C barrel and 5 kg load. Typical extrusion-grade PA12 values fall between 30 cm³/10 min and 70 cm³/10 min, but the exact grade-specific window must be locked against the supplier’s raw-material specification. The measured value is not a design property; it is used to verify that molecular-weight distribution and plasticizer content have not shifted during polymerization or compounding. A batch that exits the window on the low side may increase melt pressure and reduce output stability, while a high-flow batch may create wall-thickness control problems in free-form tubing.
In production-scale single-screw extrusion, this compound is processed at melt temperatures between 190 °C and 230 °C. The pellet feed is predried in a desiccant dryer at 80 °C for 4 h to 6 h when residual moisture exceeds 0.1 %; a drying-air dew point below -30 °C is specified because PA12 hydrolyzes slowly at melt temperature and moisture-induced viscosity loss produces diameter sag in free-form tube extrusion. Extruder configurations with L/D ratios of 24:1 to 30:1 and compression ratios of 2.5:1 to 3.0:1 are common. Feed-throat temperature is maintained between 170 °C and 190 °C; compression-zone setpoints range from 200 °C to 220 °C; metering and die zones are held at 210 °C to 230 °C. On a grooved-feed extruder, open-hopper operation at screw speeds above 60 min⁻¹ can overfeed the screw, causing pressure fluctuations at the die and wall-thickness variation in small-diameter tube. A similar instability appears when the screen-pack mesh is too fine for the available melt pressure, typically below 80 bar at the screen changer.
Thermal excursions above 230 °C in barrel or die zones first manifest as surface melt fracture and periodic diameter variation, then as yellowing and dispersed gel particles in the extrudate. The gel particles originate from thermo-oxidative crosslinking in the PA12 melt, which has a narrow residence-time window. Holding the melt above 240 °C for more than 10 min is sufficient to generate visible black specks when the line stops with a full screw. Plasticizer-modified PA12 grades add a further failure mode: prolonged exposure of the melt to open air at the die lip above 220 °C volatilizes the low-molecular-weight modifier fraction and deposits a tacky film on sizing sleeves. The corrective action is to reduce barrel setpoints and increase line speed, not to raise die temperature. Thermocouple drift in cast-aluminum heater bands should be corrected before starting a new lot because an indicated 230 °C at a single zone may conceal a measured metal surface temperature 15 K to 25 K higher.
Flexible tube and cable-sheath applications for this compound rely on conditioned Charpy toughness and limited water uptake. In pneumatic circuits, the material is used for tubing that must remain flexible during cold-start routing. Production qualification commonly applies SAE J844 for air brake tubing or the relevant ISO automotive tubing standard, with burst-pressure testing after condensation cycling. The grade is also used in protective flexible conduit for rail and electrical installations where a halogen-free polyamide solution is preferred over PVC. For those installations, flammability and smoke-density data must be obtained from the supplier because the black pigment and plasticizer package influence the ignition response. Continuous hot-air service is typically limited to approximately 100 °C; above that temperature plasticizer migration and oxidative stabilization become the dominant life-limiting mechanisms, and the material should be derated or replaced with an unplasticized, heat-stabilized PA12. Stress-cracking resistance to zinc chloride and synthetic road salts is one reason for selecting PA12 over PA6 in underbody tube applications.
The most direct comparison is with VESTAMID L1600, a high-viscosity unplasticized PA12 tube grade. L1621 sw exhibits a lower conditioned tensile modulus and yield stress, by approximately 30 % to 50 % depending on test-state moisture, and a Vicat softening point lower by about 20 K to 30 K. The compensating advantage is notched-impact behavior. At -30 °C, the plasticizer-modified grade retains ductile failure in standard Charpy testing, whereas the unplasticized grade can transition to brittle fracture if the molecular-weight distribution is not optimized for the wall thickness. Compared with VESTAMID L1700, a medium-viscosity injection-molding grade, L1621 sw is not the preferred choice for complex molded connectors. Its extrusion-oriented molecular-weight distribution can reduce spiral-flow length at a given barrel temperature and increase warpage in thick sections. The plasticizer system also limits the grade’s suitability for applications requiring low fogging or low total volatile organic compound emissions. Interior automotive components should therefore be evaluated against the supplier’s VOC data package rather than against generic PA12 published data.
For potable-water and direct food-contact service, published data for this specific configuration is limited. The black pigmentation and plasticizer package are formulation-dependent, so lot-to-lot change control is governed by the supplier’s raw-material specification. Users must request application-specific certifications for FDA 21 CFR, EU 10/2011, or drinking-water approvals rather than inferring compliance from generic PA12 literature. During melt processing, the compound should not be dry-blended with amine-terminated modifiers or strongly acidic melt stabilizers because these can alter amide exchange kinetics and shift melt viscosity enough to invalidate established temperature setpoints. Long-term chemical resistance in fuel-line service must be verified by immersion testing against the intended fuel blend. Aromatic components in aggressive synthetic fuels can extract the plasticizer fraction and reduce cold-impact toughness before the base PA12 resin shows visible degradation.
