Arkema Rilsamid AMN BLACK T6LD PA12 is a black-pigmented polyamide 12 compound within the Rilsamid portfolio. The T6LD suffix identifies a specific formulation that differs from unmodified PA12 in flexibility and low-temperature behaviour; the base polymer remains a long-chain aliphatic polyamide. The grade is supplied as pellets and is specified where chemical resistance, low moisture uptake, low-temperature ductility, and UV-shielding black pigmentation are required. The full supplier technical datasheet should be used to confirm exact lot values, because the suffix alone does not constitute a complete ISO 1874-1 designation block.

Published data for the specific Rilsamid AMN BLACK T6LD configuration is limited in open literature; representative values and ranges in this document refer to the plasticized PA12 class unless a certified lot value is cited. Design allowables for production parts should therefore be developed from grade-specific plaques or extruded tube rather than transferred from unplasticized PA12 data.

Material Identity and Specification Framework

The material is identified under ISO 1874-1 as a polyamide 12 extrusion or injection-moulding compound. Relevant test designations include ISO 1183-1 for density, ISO 1133-1 for melt mass-flow rate, ISO 527-1/-2 for tensile properties, ISO 178 for flexural modulus, ISO 179/1eA for Charpy notched impact, ISO 180 for Izod notched impact, ISO 75-1/-2 for heat deflection temperature, and ISO 306 for Vicat softening temperature. For black PA12 compounds, carbon black dispersion is not fully defined by a single ISO method; thermogravimetric ashing and microscopic dispersion grading are commonly used as supplementary production controls.

Reference class values in this table are compiled from published polyamide 12 and polyamide 11 family data and do not replace certified lot values for a specific batch of Rilsamid AMN BLACK T6LD.

What processing boundary separates acceptable thin-wall tube from black-spec and splay defects?

Pre-drying is the first boundary condition. PA12 pellets exposed to ambient air at relative humidity above 60% for more than 8 h can absorb sufficient water to generate splay and reduce melt strength in thin-wall tube. Supplier drying guidance for PA12 generally specifies 4 h to 8 h at 80°C to 90°C in a desiccant dryer to a residual moisture below 0.10%. For black plasticized grades, the dryer and hopper must be cleaned to prevent carbon black fines from accumulating; a devolatilizing vacuum vent on the extruder is not a substitute for pellet drying when moisture content exceeds 0.20%.

Melt temperature profiles for plasticized PA12 typically range from 210°C to 250°C across the feed, compression, and metering zones of a 24:1 or 25:1 single-screw extruder. Since the plasticizer reduces melt viscosity, melt temperature above 260°C can initiate thermal-oxidative chain scission. The first visible result is usually brown streaking, followed by black specks from degraded carbon black agglomerates. Pressure at the breaker plate should be monitored; melt pressure variation above ±0.5 MPa over a 30-minute window has been associated with feed-induced viscosity oscillation in production-scale PA12 extrusion. Screw configuration with a 3:1 compression ratio and a barrier flight is commonly specified. Open-channel screws without barrier elements may deliver uneven output and poor pigment dispersion. At the die, plasticized PA12 exhibits lower die swell than unplasticized PA12; die gaps for 6 mm to 12 mm tubing should be sized 10% to 15% above target wall thickness to allow draw-down without excessive orientation.

Rheologically, plasticized PA12 exhibits shear-thinning over shear rates from 10 s⁻¹ to 1000 s⁻¹. Capillary rheometry according to ISO 11443 shows a reduction in apparent viscosity at 100 s⁻¹ and 230°C from typical unplasticized PA12 values above 600 Pa·s to plasticized values commonly in the 100 Pa·s to 300 Pa·s range. This reduction permits lower pressure drop in spiral tube dies but also reduces extrudate melt strength. A draw-down ratio above 2:1 may induce diameter variation and thickness bands; closed-loop diameter gauging with haul-off tension below 0.5 N/mm² is typical on production lines.

Comparative property shifts among plasticized and unplasticized long-chain polyamides

The plasticizer package in Rilsamid AMN BLACK T6LD shifts modulus and hardness downward while increasing low-temperature ductility. Compared with unplasticized PA12, plasticized PA12 lowers tensile modulus from 1,300 MPa–1,600 MPa to 300 MPa–900 MPa and lowers Shore D hardness from 70–75 to 55–70. The low-temperature impact limit also moves downward; plasticized PA12 can retain flexible behaviour below -40°C where unmodified PA12 may become brittle depending on moisture content and wall geometry. Against PA11, the PA12 backbone has a lower amide group concentration, which reduces equilibrium water absorption and improves dimensional stability in humid air; however PA11 offers a higher melting temperature by approximately 10°C to 15°C. Against polyether-block-amide elastomers, PA12-P retains polyamide chemical resistance and lower gas permeation but does not match the elastic recovery of PEBA in high-rebound tubing.

Chemical exposure is a separate selection constraint. PA12-P resists aliphatic hydrocarbons, zinc chloride solutions, and many oils; polar solvents, strong acids, and oxidizing agents attack the amide linkage. The grade should not be used with concentrated formic acid, phenol, or hot glycol-based brake fluids unless verified for the specific service environment. When replacing unplasticized PA12 with PA12-P in a fluid-contact part, plasticizer migration into the medium should be evaluated by total organic carbon analysis or extractables testing, because plasticizer loss can change tube stiffness over time and contaminate sensitive media.

Water uptake of PA12-P at 23°C and 50% RH typically reaches 0.6% to 0.8%; at saturation in 23°C water the value increases to 1.3% to 1.6%. The resulting dimensional change is lower than that of PA6 and PA66. This lower water affinity is a primary reason PA12 is selected over short-chain polyamides for fuel and pneumatic lines exposed to humidity.

When low-temperature flexural fatigue overrides stiffness requirements

Design selection between Rilsamid AMN BLACK T6LD and a higher-modulus PA12 should be driven by cyclic flexural strain at low temperature. In pneumatic tubing subjected to -40°C flex cycles, plasticized PA12 delays cracking by reducing flexural modulus and increasing elongation at break; the trade-off is reduced tensile strength and lower upper service temperature. If a minimum tensile strength of 50 MPa at 23°C is required, plasticized PA12 may be marginal unless wall thickness is increased. Creep and stress relaxation data under continuous load should be generated according to ISO 899-1 or ISO 899-2, not inferred from short-term tensile data. The black colour and plasticizer package can also affect weld line strength in injection-moulded connectors; a 20% to 40% loss in Charpy notched impact at a weld line relative to bulk material is commonly observed in polyamide 12 and should be included in part design safety factors.

Application use reported for black plasticized PA12 grades includes pneumatic tubing, fuel vapour vent tubing, cable ties, and protective sheathing for optical fibres. The black pigmentation provides UV shielding for outdoor service; however UV stabilization should be confirmed by extended weathering tests such as ISO 4892-2 or SAE J2527 if the component is exposed to direct sunlight. Thin-wall tube made from PA12-P is typically post-extrusion annealed at 120°C to 140°C for 2 h to relieve orientation and stabilize burst strength according to SAE J844 or equivalent internal specifications. In injection-moulded fittings, the grade can be processed with mould temperatures of 40°C to 80°C; higher mould temperatures improve crystallinity development and reduce post-mould shrinkage.

Regulatory compliance and material substitution verification

Compliance must be confirmed grade-specific and lot-specific. The table below summarizes the principal regulatory and standards frameworks relevant to a black plasticized PA12 compound. Inclusion of a framework does not imply automatic compliance for Rilsamid AMN BLACK T6LD; supplier declarations and analytical data are required for the specific grade and batch.

Storage conditions remain integral to processability. Unopened 25 kg bags should be kept at 10°C to 30°C in a closed, clean area. If opened bags are not consumed within 8 h at ambient relative humidity above 60%, the remaining pellets should be sealed with desiccant or dried before use. Drying temperature should not exceed 90°C because carbon-black-containing PA12 can oxidize at exposed pellet surfaces during extended oven residence. Desiccant dryers with a -40°C dew point are preferred over hot-air ovens for black grades.

Published data for the specific Rilsamid AMN BLACK T6LD weld-line property retention and long-term fatigue are limited; design allowables should be developed on production-representative plaques or tube samples. Material substitution from unplasticized PA12, PA11, or PEBA should be validated through full part testing under the intended thermal, chemical, and cyclic loading conditions, not by nominal property comparisons alone.