| HS Code | 590680 |
| Density | 1.01 g/cm³ |
| Melting Point | 178 °C |
| Glass Transition Temperature | -30 °C |
| Water Absorption Saturation | 0.7 % |
| Tensile Strength At Yield | 30 MPa |
| Elongation At Break | 200 % |
| Flexural Modulus | 400 MPa |
| Charpy Impact Strength Notched 23 C | 40 kJ/m² |
| Shore Hardness D | 55 |
| Vicat Softening Temperature | 100 °C |
| Heat Deflection Temperature 1 8 Mpa | 40 °C |
| Volume Resistivity | 10^12 Ω·cm |
As an accredited Evonik Vestamid L2121 Plasticized Nylon 12 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Evonik Vestamid L2121 plasticized nylon 12 is supplied as pellets in 25 kg moisture-proof bags, protecting against contamination. |
| Container Loading (20′ FCL) | 20' FCL: Evonik Vestamid L2121 in sealed bags on pallets, properly secured, ventilated, protected from moisture and heat. |
| Shipping | Evonik Vestamid L2121 Plasticized Nylon 12 ships as non-hazardous granules in sealed moisture-proof bags or drums. Keep dry, away from direct sunlight, and store below 30°C. Avoid crushing or puncturing packaging to prevent moisture ingress, which can affect processing. Standard dry van transport is suitable; no special hazardous cargo declaration required. |
| Storage | Store Evonik Vestamid L2121 in its original, sealed container in a cool, dry, well-ventilated area. Protect from direct sunlight, heat, and excessive humidity, as nylon 12 absorbs moisture. Keep away from oxidizing agents and incompatible materials. Under proper conditions, shelf life is typically two years. |
| Shelf Life | Shelf life is typically 2 years when stored unopened in original packaging, in a cool, dry place. |
In heavy-duty vehicle air braking systems, straight and coiled tubing is extruded from Evonik Vestamid L2121 where the plasticized nylon 12 grade meets low-temperature flexibility requirements without the higher moisture uptake of short-chain aliphatic polyamides. Pre-drying is executed at 80 °C for 4–6 h in a desiccant dryer until residual moisture is ≤0.10 wt%, measured by ISO 15512. Lines operating in ambient relative humidity above 60% require closed hopper conveying or low-dew-point shielding because surface moisture re-uptake shifts melt viscosity and creates micro-voids in the tube inner wall. Single-screw extruders with 25:1–30:1 L/D, a three-zone screw, and compression ratio 2.5:1–3.0:1 are run with melt temperature at the die held between 210–230 °C. High-shear barrier screws are avoided because excessive shear heating accelerates plasticizer volatilization at the screw tip. A melt pump between screw tip and die is set to maintain inlet pressure 40–80 bar; this stabilizes wall concentricity within ±0.05 mm on standard sizes such as 8×1 mm and 12×1.5 mm. The extrudate enters a vacuum sizing tank at −0.2 to −0.5 bar with water at 15–25 °C, followed by laser diameter gauging and sequential ink-jet marking. Finished tube is tested against SAE J844 criteria including cold impact at −40 °C, alcohol resistance after exposure, and burst pressure not less than 4× maximum rated working pressure. The terminal product is cut and coiled as coloured brake tubing with outside diameters from 6.35 mm to 15.88 mm. Continuous immersion in glycol-based brake fluids or direct exposure to hot methylene chloride cleaning solvent is outside the validated service envelope and causes stress cracking at tight bend radii.
Direct extrusion of slit harness conduit from the same base resin is carried out on a 45 mm extruder with 30:1 L/D using a crosshead die and internal mandrel, followed by in-line slitting, water quenching, and puller diameter gauging. The melt temperature at the die is held at 220–235 °C; die drool from plasticizer fractions becomes visible when the die lip runs hotter than 240 °C, which forces a line stop every 8–12 h for lip wiping. Regrind from start-up scrap is limited to ≤20 wt% because higher content narrows slit closure force and produces open-slit failures after repeated flexing. Conformance for machine-tool dress packs and cable protection is assessed under NFPA 79 for continuous flexing and UL 1581 for flame propagation. Where UL 94 V-0 classification is mandatory, the unmodified grade is not suitable because unfilled plasticized PA12 typically rates HB and would require halogen-free flame-retardant modification not inherent to this material. The finished conduit is supplied in nominal inside diameters from 10 mm to 50 mm with slit overlap of at least 1.5 mm.
Three sources of variation dominate when a 6×4 mm or 8×5 mm tube is drawn to a 0.8 mm wall target with Vestamid L2121: melt viscosity drift after regrind, vacuum tank turbulence, and die-lip contamination from plasticizer migration. On production lines, a gear pump is placed between screw tip and die with inlet pressure 30–60 bar; without a gear pump, screw surge moves wall thickness outside ±0.03 mm at line speeds above 60 m/min. Die temperature is kept at 225 °C ±2 °C, and the first sizing sleeve is set to −0.3 bar vacuum with 18 °C water. Tube dimensions are checked by laser shadow gauge every 250 ms; eccentricity above 0.05 mm triggers automatic vacuum adjustment or line-speed reduction. Burst testing is performed at 3× rated working pressure at 23 °C using nitrogen, and connector pull-out is validated per DIN 73378. Thick-walled sections above 1.2 mm require a heated straightening die set at 120 °C because plasticized PA12 retains a moderate coil set after water cooling.
Small nonroad engines use coextruded low-permeation fuel vapour return lines with an EVOH barrier layer, a maleic anhydride-grafted tie layer, and an outer jacket of Vestamid L2121. The outer PA12 layer is required where crimped connectors generate hoop stress and the line must survive −40 °C cold impact after fuel exposure. Coextrusion is run on a multilayer die at 220–230 °C melt temperature for the PA12 outer layer, while the EVOH layer is held below 210 °C to prevent gel formation. Screen packs upstream of the die are 60/80/100 mesh to capture tie-layer cross-linked particles; pack pressure above 120 bar signals filter blinding. Evaporative emission compliance is evaluated under EPA 40 CFR Part 1060 for small nonroad spark-ignition engines. Because plasticizer migration in ethanol blends above E10 can soften the tie-layer interface, published data for this specific configuration is limited; a 1,000 h static exposure in E10 at 60 °C with weekly burst and bend checks is used as a screening method.
Compliance boundaries for the above segments are consolidated in the following matrix; values are specification requirements, not product guarantees.
| Downstream segment | Normative reference | Test method or condition | Boundary condition |
|---|---|---|---|
| Pneumatic brake tubing | SAE J844 | cold impact at −40 °C; burst 4× | compressed air only; not for glycol brake fluid immersion |
| Cable harness conduit | NFPA 79 / UL 1581 | continuous flex; flame propagation | UL 94 V-0 requires flame-retardant modification |
| Pneumatic control line | DIN 73378 | burst at 3×; connector pull-out | wall ≤0.8 mm requires gear pump stabilisation |
| Small-engine fuel vent line | EPA 40 CFR Part 1060 | evaporative canister load | ethanol blends above E10 require validation |
Unpressurized wire-harness wrap profiles extruded from Vestamid L2121 for robotic dress packs require no vacuum calibration and are controlled only for slit geometry, inner diameter, and closure force; conformity is limited to RoHS Directive 2011/65/EU and an internal flex-cycle gate of 1,000,000 cycles at 25 °C.
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The designation Evonik Vestamid L2121 refers to a plasticized extrusion grade of polyamide 12 based on laurolactam. The base polymer contains a repeating methylene sequence separating the amide linkages; this structural arrangement lowers amide-group density relative to PA6 and PA66, reduces equilibrium water absorption, and limits moisture-driven dimensional change. In L2121, a compounding step introduces a plasticizer that disrupts interchain hydrogen bonding, increases free volume, and shifts the mechanical response from stiff semi-ductile behavior toward low-modulus flexible behavior. The grade is intended for continuous extrusion of flexible tubing, cable jacketing, and profiles requiring repeated flexing at low ambient temperature.
Because the material belongs to the Vestamid family, the specification framework draws on Evonik technical datasheets and standardized polyamide test methods. Relevant test procedures include ISO 1183-1 for density, ISO 11357-3 for melting temperature by differential scanning calorimetry, ISO 527-1/-2 for tensile properties, ISO 868 for Shore hardness, ISO 62 for water absorption, and ISO 179-1/1eA for notched Charpy impact. These methods provide reproducible comparison points for incoming inspection and process validation; they do not by themselves constitute field-performance guarantees.
The table below summarizes the practical control window documented in technical literature for plasticized polyamide 12 extrusion grades of this class. Since L2121 is plasticized, tensile modulus and Shore D measurements are more sensitive to specimen conditioning than equivalent tests on unplasticized PA12. Values should be interpreted against the conditioning protocol recorded on the batch certificate.
| Property | Test standard | Typical interval |
|---|---|---|
| Density at 23 °C | ISO 1183-1 | 1.01–1.03 g/cm³ |
| Melting temperature, DSC second heat | ISO 11357-3 | 172–176 °C |
| Vicat softening temperature, 50 N, 50 K/h | ISO 306 | 145–155 °C |
| Tensile modulus, 1 mm/min | ISO 527-1/-2 | 180–280 MPa |
| Tensile stress at yield, 50 mm/min | ISO 527-1/-2 | 8–15 MPa |
| Nominal strain at break | ISO 527-1/-2 | >200 % |
| Shore D hardness, 15 s | ISO 868 | 50–60 |
| Water absorption, saturated at 23 °C | ISO 62 | 1.2–1.6 % |
| Charpy notched impact at −30 °C | ISO 179-1/1eA | 5–10 kJ/m² |
The plasticizer effect is visible in the reduction of dry tensile modulus to roughly 180–280 MPa while nominal strain at break remains above 200 %. When specimens are conditioned to equilibrium at 23 °C and 50 % relative humidity according to ISO 1110, modulus decreases further because absorbed water acts as an additional plasticizing agent. The Vicat softening temperature of 145–155 °C indicates moderate thermal dimensional stability, but continuous exposure above 80 °C requires evaluation for plasticizer loss, oxidative degradation, and progressive hardening.
At saturation, PA12 absorbs approximately 1.2–1.6 % water by mass under ISO 62. This is significantly lower than PA6 saturation of about 9–10 % or PA66 saturation of about 7–8 %. The lower amide-group concentration of PA12 reduces the number of polar hydrogen-bonding sites available for water. In L2121, the plasticizer occupies some of those polar interaction sites, but the total plasticizing effect of moisture remains measurable; dimensional change from dry to conditioned state should be quantified for tubing with narrow inner-diameter tolerance.
Production extrusion of L2121 is normally carried out on single-screw extruders with screw lengths of 30:1 to 36:1 and medium-shear screw geometry. The polymer requires desiccant drying at 80 °C for 4–6 hours to reduce moisture below 0.10 % by mass; wet pellets generate surface roughness, microvoiding, and viscosity fluctuation. Die temperatures are typically set from 200 °C to 230 °C, with barrel temperatures ramped from 160 °C in the feed zone to 220 °C at the metering section. Because the plasticized melt is more compressible than unplasticized PA12, vacuum sizing is critical. External calibrators operating at −0.3 bar to −0.6 bar gauge are used for tubing to control wall-thickness drift. Melt filtration through screen packs of 40–60 mesh is recommended for thin-wall profiles to reduce gel accumulation at the die lip.
For injection molding of fittings and connectors in the same material family, barrel temperatures of 190–220 °C and mold temperatures of 30–60 °C are common. Screw rotation rate should be limited to avoid excessive shear heating. Although plasticized PA12 may show a lower melt-temperature rise than unplasticized PA12, it also has a narrower thermal degradation onset. Hold pressure should be profiled to compensate for the higher melt compressibility and to prevent sink marks in thick bosses. During start-up, a purging grade of polyamide is recommended because plasticized PA12 can produce die lip build-up after intermittent stops. Purging compounds containing calcium carbonate are not recommended; residues can be retained in dead spots and alter surface finish. The barrel should be purged with an unplasticized PA12 of equivalent viscosity before extended shutdown to reduce plasticizer condensation on screw roots and check rings.
The principal distinction between L2121 and unplasticized PA12 extrusion grades is the large reduction in flexural stiffness. Unplasticized PA12 typically exhibits a tensile modulus of 1000–1400 MPa and Shore D hardness of 70–75, making it suitable for rigid tubing but prone to cold fracture when flexed repeatedly below −20 °C. L2121 shifts tensile modulus into the 180–280 MPa interval and reduces Shore D to 50–60. The retained polyamide backbone preserves more chemical resistance and creep resistance than a purely polyolefin elastomer would provide.
| Attribute | Unplasticized PA12 | Vestamid L2121 | PA11 | Polyether-block-amide |
|---|---|---|---|---|
| Tensile modulus | 1000–1400 MPa | 180–280 MPa | 900–1200 MPa | 20–200 MPa |
| Shore D hardness | 70–75 | 50–60 | 65–70 | 30–65 |
| Water absorption at saturation | 1.2–1.5 % | 1.2–1.6 % | 1.8–2.0 % | composition-dependent |
| Low-temperature impact retention | moderate below −20 °C | high below −30 °C | high | very high |
Compared with polyether-block-amide materials, L2121 does not rely on soft polyether segments for flexibility. The result is lower elastic recovery than a high-hard-segment polyether-block-amide, but generally better retention of fuel barrier behavior. Compared with PA11, the longer methylene sequence in PA12 reduces equilibrium water absorption. Plasticizer migration, however, can offset that moisture advantage if the material is exposed to hot aliphatic hydrocarbons for extended periods.
Plasticized PA12 of this class is selected for pneumatic tubing and low-pressure fuel-vapor applications because the polyamide phase retains a measurable diffusion barrier to nonpolar fluids. Exposure to hot aliphatic hydrocarbons, ketones, and chlorinated solvents can extract the plasticizer over time, producing progressive hardening and dimensional contraction. The extraction rate is temperature-dependent; continuous exposure above 60 °C in diesel fuel or gasoline vapor requires validation with the actual fluid composition, not only immersion in reference fuels. Relevant testing may include ISO 1817 for resistance to liquids, with mass change and Shore D change measured after 70 hours, 168 hours, and 1000 hours.
This behavior distinguishes the material from internally plasticized polyamide elastomers, where the soft block is covalently bonded and migration is lower. In applications where plasticizer extraction cannot be tolerated, an unplasticized PA12 or a polyether-block-amide grade should be evaluated. Where the specification requires a single-material tubing solution with lower flexural modulus and standard polyamide chemical anchoring, L2121 provides an established processing compromise. The plasticizer also alters the pressure–volume–temperature behavior of the melt; in practical extrusion, this is observed as lower screw torque at equivalent throughput and higher output dependence on die restriction. Excessively high barrel temperature accelerates plasticizer vaporization, and a vented barrel without sufficient vacuum may produce porosity if the additive package is partly lost before the die.
In continuous-flex pneumatic tool supply lines produced on 45 mm single-screw extruders with grooved feed sections, the primary process failure mode is wall-thickness oscillation when the vacuum sizing sleeve is positioned too close to the die face. A free-run distance of 10–30 mm between die exit and sizing inlet is typically maintained to allow a thin melt film to stabilize before solidification. If line speed is increased, surface gloss can degrade and a helical weld line may appear; reducing die gap or raising melt temperature within the 200–230 °C window usually resolves the defect. These process observations reflect production-scale equipment behavior and should not be interpreted as material acceptance criteria.
