Extruded thermoplastic air brake tubing for commercial vehicle circuits is a volume downstream application of Arkema Rilsamid AESN BLACK P110 TL PA12-I. The compound is charged at 100% virgin granules for first-quality production, with clean, desiccant-dried start-up scrap and off-spec coils reincorporated at 20 wt% regrind to 80 wt% virgin, provided regrind particle size is controlled below 2.0 mm and bulk density is maintained above 0.55 g/cm³ to prevent feed bridging. Extrusion is performed on a 45 mm or 60 mm single-screw extruder with L/D 30:1 barrier screw and 80/100 mesh screen pack; barrel profile is set from 200 °C to 245 °C, die at 245 °C, and melt temperature does not exceed 250 °C. Pre-drying at 80 °C for 4–6 h to 0.10 wt% moisture or below is mandatory, because moisture above 0.15 wt% produces surface porosity and microbubble defects that reduce −40 °C burst performance. The tube is calibrated under −0.06 to −0.08 MPa vacuum and cooled in water at 18–25 °C, then laser-marked and coiled. Compliance is anchored to SAE J844 for thermoplastic air brake tubing, ISO 7628 for dimensional and environmental service, ISO 179-1:2023 for low-temperature notched impact, and ISO 1183-1:2019 for density control. Terminal products are 6 mm, 8 mm, 10 mm, and 12 mm OD tube coils, straight cut lengths, and push-in connector assemblies for truck, trailer, and bus air systems.

Does SAE J2260 Permit Monolayer PA12 Vapour Return Lines When the Evaporative Emissions Budget Is Tank-Side Controlled?

For light-duty gasoline and hybrid platforms, fuel vapour return and rollover vent lines are produced as monolayer PA12 only in low-pressure branches where the evaporative emissions budget is managed by the tank-side canister and sealing system rather than the line wall itself. In these emission-critical wall-thickness applications, Rilsamid AESN BLACK P110 TL PA12-I is charged at 100% virgin compound; if end-user specifications permit regrind, the addition ratio is capped at 10 wt% of clean, dried in-house scrap. The downstream line uses a 50 mm single-screw extruder with L/D 25:1 and a low-shear screw, because production trials on high-shear barrier screws have recorded melt temperature excursions above 265 °C that create carbon-black agglomerates and specks in 1.5 mm wall tube. Head pressure is maintained at 12–18 MPa, die temperature is 245 °C, and the tube passes through a 20 ± 3 °C water bath under −0.04 MPa calibration vacuum before in-line leak testing at 0.5 MPa. Drying is performed at 80 °C for 4–6 h to residual moisture below 0.10 wt%. Standards include DIN 73378 for polyamide tubing in motor vehicles, ASTM D638-14 for tensile yield at 23 °C, ISO 179-1:2023 for notched impact at −40 °C, and SAE J2044 for quick-connector compatibility. Terminal products include 6 mm and 8 mm OD vapour return lines with injection-moulded PA12 quick connectors, supplied in cut lengths with barcode traceability.

In automated assembly cells, CNC end-of-arm tooling, and semiconductor packaging machinery air circuits, the grade is selected for stable bore retention in dry compressed-air service because low equilibrium moisture uptake reduces dimensional swell compared with PA6. The compounding ratio is 100% virgin Rilsamid AESN BLACK P110 TL PA12-I for clean-room and control-line service, while up to 25 wt% cleaned, dried post-industrial scrap from the same grade may be incorporated in non-critical plant-air lines after re-drying at 80 °C for 4 h. The extrusion process uses a 30 mm single-screw extruder with L/D 28:1, barrel temperatures 190–240 °C, die temperature 240 °C, and melt temperature not above 250 °C. Closed-loop vacuum sizing at −0.05 MPa and water cooling at 20 °C control wall thickness to ±0.03 mm as measured by an ultrasonic gauge. Compliance is verified against ISO 4414:2010 for pneumatic system safety, ISO 14743:2004 for push-in connector performance, and ASTM D1599-18 for short-time burst pressure of thermoplastic tubing. End products are 4 mm, 6 mm, 8 mm, and 10 mm OD straight-form and re-coil pneumatic lines for push-in fittings.

Hot Diesel Recirculation Lines: Chloride-Exposure Cracking Resistance and Extrusion Melt-Pump Control in Heavy-Duty Frame Rails

Hot diesel return lines on heavy-duty trucks and agricultural machines are extruded from Rilsamid AESN BLACK P110 TL PA12-I because the PA12 backbone resists chloride-induced stress cracking from road de-icing salts and exhibits lower fuel swelling in continuous diesel contact at 80 °C than plasticized PA11 or PA6. The charge formulation is 100% virgin compound for OEM high-pressure fuel return branches; after start-up, 15 wt% in-house regrind is accepted only when ground below 3.0 mm, re-dried to 0.10 wt% moisture, and blended in a closed-loop gravimetric system to prevent carbon black concentration drift. The downstream process uses a 50 mm grooved-feed extruder with L/D 30:1, a melt pump, and a 20/40/60 mesh screen pack; barrel temperatures are 200 °C to 245 °C, melt pump inlet pressure is held at 8–12 MPa, and die temperature is 245 °C. Post-die cooling is in water at 20 °C, with laser diameter measurement at 0.02 mm resolution. Standards are DIN 73378 for automotive polyamide tubing, ASTM D638-14 for tensile yield, ISO 1133-1:2022 for melt flow stability, and ASTM D543-21 for chemical resistance in reference fuel mixtures. Terminal products are 8 mm, 10 mm, and 12 mm OD smooth-wall or spiral-wrapped diesel recirculation lines assembled into truck and tractor fuel systems.

When PA12 Jacketing Replaces PVC and PA6 in Automotive Wire Harness Channels and Battery Cable Protection

In engine compartments and battery cable routing, automotive wire harness channels are produced from Rilsamid AESN BLACK P110 TL PA12-I when design specifications require −40 °C impact resistance, mineral-oil resistance, and abrasion resistance under dynamic routing. For sheathing extrusion, the charge is 100% virgin material because even 5 wt% regrind with moisture above 0.10 wt% can produce pinholes in thin-wall 0.5–1.0 mm jackets; for non-safety harness conduit, regrind is limited to 10 wt% and dried at 80 °C for 4 h. The process is pressure extrusion through a 45 mm single-screw extruder with L/D 28:1 and a crosshead die; barrel zones are 190–240 °C, die temperature is 240 °C, and line speeds range from 30 m/min to 80 m/min depending on wall thickness. Compliance is referenced to ISO 6722-1:2021 for road vehicle cable dimensions and abrasion, LV 112 for OEM harness requirements, ASTM D638-14 for tensile yield, and IEC 60068-2-6 for vibration exposure. Terminal products include split convoluted loom, corrugated conduit, and smooth-wall jacketing for engine harnesses and EV battery cable runs.

Corrugated protective conduit for hydraulic excavator boom harnesses and agricultural sprayer boom cable routing is produced from Rilsamid AESN BLACK P110 TL PA12-I as a black, UV-stabilized replacement for PA6 and polypropylene where mineral-oil mist and low-temperature flexing occur. The recipe uses 100% virgin compound for outdoor UV exposure; if surface defects appear at plant relative humidity above 60% RH, processors check dryer dew point at −40 °C and residual moisture below 0.08 wt% because carbon-black grades retain adsorbed surface moisture. Extrusion is performed on a 60 mm single-screw corrugator with L/D 30:1, barrel temperatures 200–250 °C, die temperature 250 °C, corrugator mold temperature 60–80 °C, and vacuum forming at −0.07 MPa. Compliance standards are ISO 178:2019 for flexural modulus, ISO 179-1:2023 for notched impact at −40 °C, and ISO 4892-2 for UV resistance of carbon-filled grades. Terminal products include corrugated conduit with internal diameters from 10 mm to 28 mm, slit and unslit, for construction, agriculture, and material-handling equipment.