Arkema Rilsamid AESNO P401 PA12 is a plasticized polyamide 12 grade within the Rilsamid extrusion portfolio, supplied as natural cylindrical pellets for flexible tube, conduit, and blow-moulded components. The grade nomenclature follows Arkema’s Rilsamid system, with the P suffix indicating a plasticized formulation and the 401 designation referencing a high-melt-viscosity variant intended to support parison stability and narrow wall-thickness control during free-surface extrusion. Specification data are generated in accordance with ISO 1133-1 for melt volume-flow rate, ISO 527-1/-2 for tensile properties, ISO 179/1eA for notched Charpy impact, ISO 868 for Shore D hardness, ISO 306 for Vicat softening temperature, ISO 1183-1 for density, and ISO 62 for water absorption. The as-received polymer is not dry enough for melt processing; equilibrium moisture at 23 °C and 50% relative humidity is approximately 0.7% in polyamide 12, and this level is sufficient to produce hydrolytic chain scission during extrusion. Representative property ranges for plasticized PA12 extrusion grades place flexural modulus between 600 MPa and 900 MPa, Shore D hardness between 55 and 65, and notched Charpy impact at 23 °C in the no-break category. The melt volume-flow rate at 235 °C with a 2.16 kg piston is typically controlled below 10 cm³/10 min to preserve extrudate strength. The plasticizer increases free volume in the amorphous phase, which lowers stiffness and hardness but also raises the permeability of small hydrocarbon molecules compared with unplasticized PA12.

Chemical compatibility is dominated by the polyamide 12 amide group and the plasticizer package. Strong mineral acids, formic acid, and phenolic solvents are aggressive; diesel, zinc chloride brines, and alkaline road salts are tolerated within moderate temperature limits. Immersion testing according to ISO 1817 in IRM 903 oil at 100 °C for 70 h is used to compare extraction effects; a Shore D hardness loss greater than 5 points after immersion suggests plasticizer migration and warrants a design review. Low-temperature behaviour is typically assessed by ISO 974; plasticized PA12 grades generally remain ductile below -40 °C, although the exact brittleness temperature is thickness- and conditioning-dependent.

How Does AESNO P401 Differ from Unplasticized PA12 and PA11 Grades?

The clearest differentiator from unplasticized PA12 is the intentional reduction in flexural modulus under ISO 178. Unplasticized PA12 extrusion grades typically exhibit flexural modulus in the 1000–1400 MPa range; AESNO P401 lies in the 600–900 MPa range. Shore D hardness shows a parallel shift from above 70 to approximately 55–65, and the Charpy notched impact response moves from a partial-break value of 5–10 kJ/m² at 23 °C to a no-break response. These changes are produced by plasticizer incorporation into the amorphous domains; the crystalline melting temperature is less affected and remains in the 170–178 °C range under ISO 11357-3.

Against PA11, the principal measurable distinction is saturated water uptake. Natural PA11 under ISO 62 commonly reaches 1.8–2.0% at saturation, whereas PA12 formulations remain in the 1.4–1.6% range. In humid or liquid-contact service, this difference affects dimensional growth and tensile property retention. Some plasticized PA11 grades may offer lower flexural modulus than AESNO P401, but the PA12 backbone of AESNO P401 provides the lower saturation moisture uptake. The high-viscosity P401 variant also differs from lower-viscosity PA12 injection grades by melt volume-flow rate: P401 is held below 10 cm³/10 min, while many PA12 injection grades exceed 15 cm³/10 min under the same ISO 1133-1 condition. This difference appears on production lines as higher die-entry pressure during extrusion and a wider stable parison window at low take-off ratios.

Prior to melt processing, moisture control is the first processing boundary. PA12 equilibrates at roughly 0.7% moisture at 23 °C and 50% relative humidity; for thin-wall tube extrusion, the moisture content must be reduced below 0.10% to limit hydrolytic degradation and surface roughness. A desiccant dryer at 80–90 °C with a dew point of -30 °C or lower for 4–6 h is recommended for virgin pellets exposed to ambient air for more than 24 h. Regrind may be incorporated up to 20 wt%, provided it is dry and free of oil; higher regrind fractions can shift melt viscosity and create batch-to-batch colour variation. If ambient relative humidity exceeds 60%, open residence in the feed throat should be shorter than 30 min or a closed hopper with dry-air purge should be used.

On a single-screw extruder with L/D 24:1–30:1, a three-zone screw with compression ratio 2.5:1–3.0:1, and a grooved feed section, the barrel profile from feed to metering is typically 220–245 °C. The melt temperature at the die should not exceed 260 °C; above this threshold, plasticizer volatilization and amide oligomer plate-out become measurable defects. Die-head pressure in the 10–30 MPa range is usual for tube sizing. Pressure variability greater than ±0.5 MPa at constant screw speed indicates feed instability, bridging in the hopper, or a worn screw; the feed throat should be cooled to 40–60 °C to prevent premature pellet surface fusion. Melt filtration with screen packs of 80–120 mesh is used to remove char particles; a screen pack pressure rise above 5 MPa indicates that the screens should be changed. At screw speeds above 60 rpm on a 45 mm extruder, shear heating may raise melt temperature by 5–10 °C above the barrel set point; a melt-temperature probe should therefore be fitted in the adapter, not at the die lip, to avoid false readings. Die swell in the P401 grade is more pronounced than in lower-viscosity PA12; calibration sleeves are typically oversized by 10–20% relative to the final outside diameter. Vacuum sizing with closed-loop water temperature of 15–25 °C is used to set the outer diameter; wall-thickness variation below ±0.05 mm is achievable only when screw speed and puller speed are coupled through a gravimetric hopper or melt-pump system.

For injection moulding of fittings and connectors, barrel temperatures of 230–250 °C and mould temperatures of 40–80 °C are used. The required clamp force is calculated from the projected area and a cavity pressure of 30–60 MPa. Holding pressure should be sustained until gate freeze; the screw cushion should be 2–4 mm to avoid sink marks. Flash formation is controlled by maintaining a mould parting line fit below 0.03 mm and by limiting injection velocity in thin sections. Because the grade is plasticized, shrinkage is generally lower than that of unplasticized PA12; mould shrinkage data under ISO 294-4 should be obtained from the supplier for the specific wall thickness.

When Low Extractables and Burst Strength Govern the Application

In automotive air-brake tubing, the controlling standards include SAE J844 for non-metallic tubing and FMVSS 106 for brake hoses; the material must provide burst pressure at 23 °C and elevated temperature, resistance to zinc chloride and methanol, and cold flexibility. For a monolayer tube with outside diameter 10 mm and wall thickness 1 mm, the hoop stress equation gives a theoretical burst pressure near 6 MPa when the tensile stress at yield is 30 MPa. At 80 °C the yield stress is lower, and the burst pressure is commonly derated by a factor of 0.6 or more for plasticized PA12. The wall thickness must therefore be increased or a fibre-reinforced layer added when the service pressure exceeds 1.0 MPa at elevated temperature.

Diesel fuel vapour lines are assessed under SAE J2260; the permeation ceiling depends on the vehicle class and regional regulation. Unplasticized PA12 provides lower permeation than plasticized PA12, so AESNO P401 is not the first choice when the permeation limit is below 1 g/m²/day. Published permeation data for this exact plasticized formulation are limited; validation should be performed on a production-scale extrusion line with online diameter and wall-thickness gauges. In compressed-air circuits exposed to mineral oil, compatibility is evaluated under ISO 1817; a hardness loss greater than 5 Shore D points after immersion in IRM 903 oil at 100 °C for 70 h indicates plasticizer extraction and should be treated as an operational boundary. Continuous service above 100 °C is not recommended for this grade unless field data from the specific oil formulation support the higher temperature. Flexible cable conduits and hydraulic hose sheaths use the low flexural modulus to reduce the minimum bend radius; however, the DIN 53516 abrasion loss of plasticized PA12 is higher than that of unplasticized PA12, and coextrusion of a harder outer layer is a common production strategy to separate flexibility from wear resistance. At sub-zero temperatures, plasticized PA12 retains ductile behaviour; ISO 974 brittleness temperature for this class is commonly below -40 °C, but the actual value is sensitive to moisture and plasticizer loss. In fuel-vapour service, the combination of plasticizer migration and low-molecular-weight fraction extraction can increase hardness over 3000 h of hot-air aging; accelerated aging according to ISO 188 at 100 °C for 168 h is used as a screening tool. Tensile elongation retention after aging should remain above 50% of the unaged value; lower retention indicates that the selected plasticizer system is not suitable for the continuous-use temperature.

Regulatory Status and Incompatibility Boundaries

Compliance with REACH and RoHS is grade-specific. The manufacturer should be asked for a full material declaration under EU Regulation (EC) No 1907/2006 and Directive (EU) 2015/863 when electrical or electronic equipment is involved. For food-contact uses, status under FDA 21 CFR 177.1500 and EU Regulation (EU) No 10/2011 must be confirmed for the exact plasticizer package; natural PA12 chemistry may be listed, but additives and colourants can alter the compliance status. The material should not be compounded with amine-based nucleating agents or certain phenolic antioxidants without prior compatibility testing because amine species can complex with residual monomers and shift the crystallization temperature under ISO 11357-3. Zinc stearate and other metallic soaps used as mould release should be limited to the levels specified by the supplier; excess metal carboxylates can catalyse hydrolysis during hot-water aging, as evidenced by reduced tensile elongation after ISO 1817 water immersion. If flame-retardant grades are required, a separate halogen-free or halogenated compound should be selected rather than dry-blending additives into AESNO P401, because the high viscosity of the P401 grade may produce poor dispersion and variable flammability results under ISO 1210 or UL 94. Batch-to-batch melt volume-flow rate variation in high-viscosity PA12 can shift by ±2 cm³/10 min; incoming inspection under ISO 1133-1 should be performed on each lot before extrusion because this shift changes die-head pressure and downstream parison weight.