Arkema Rilsamid AMVO TLD PA12 is a plasticized polyamide 12 extrusion grade supplied for monolayer and multilayer tubular applications that require low-temperature flexibility, resistance to aliphatic hydrocarbons, and lower Shore D hardness than unplasticized semicrystalline polyamide 12. The base polymer is designated PA12 under ISO 1043-1:2011; the repeating unit is derived from laurolactam or ω-aminododecanoic acid, and the grade belongs to the polyamide 12 category defined in ISO 1874-1:2010. Because the TLD suffix is supplier-specific, the complete specification block and lot-specific data should be read from the current Arkema technical datasheet and certificate of analysis. The product is differentiated from general-purpose Rilsamid PA12 grades by a shift in tensile elongation, Shore D hardness, and flexural modulus, while maintaining the low equilibrium moisture uptake and dimensional stability characteristic of PA12. Primary conversion is single-screw tube extrusion with grooved-barrel feed and vacuum calibration; initial melt-temperature settings commonly fall between 220 °C and 250 °C. The grade is also suited to injection molding of fittings when the tool is maintained between 40 °C and 80 °C.

What Distinguishes the Plasticized AMVO TLD Profile from Unplasticized PA12?

Plasticization of a semicrystalline PA12 matrix lowers the glass transition, reduces flexural modulus, and increases low-temperature impact compliance. In comparative terms, a plasticized tubing grade typically exhibits a tensile modulus below 800 MPa when tested under ISO 527-2:2012, whereas unplasticized PA12 reference grades are commonly reported between 1,300 MPa and 1,700 MPa. Hardness measured by ISO 868:2003 with the Shore D scale usually falls between 55 and 65, while unplasticized grades remain above 70. These are indicative mechanical trends for plasticized PA12, not specification limits for AMVO TLD; published lot-certificate data may vary with plasticizer content and batch production. Melt-viscosity differences are quantified by melt volume-flow rate under ISO 1133-1:2022 at 235 °C with a 2.16 kg load, and the certified range appears on the lot certificate. Density measured by the ISO 1183-1:2019 immersion method is generally in the range 1.01 g/cm³ to 1.03 g/cm³, which supports lightweight tube designs relative to some filled polyamide formulations.

If the Application Requires Low Extractables and Burst Strength Retention

When AMVO TLD is extruded into air-brake tubing covered by SAE J844 or ISO 7628-1, burst strength retention after thermal and chemical exposure becomes the critical acceptance parameter. Production-scale extrusion on a 45 mm single-screw extruder with L/D 30:1 and a grooved feed bushing has shown that melt temperatures below 220 °C produce inner-surface melt fracture, and that cooling water above 25 °C in the first vacuum tank creates out-of-roundness above 0.05 mm in tubes with outside diameters below 10 mm. Moisture above 0.10% by weight, determined by ISO 15512:2019, initiates hydrolysis that reduces molecular weight and lowers burst pressure retention under ISO 1402:2021. For fuel-vapor and pneumatic lines, the plasticizer must remain within the polymer under continuous hydrocarbon contact; low-molecular-weight plasticizer migration can increase extractables and harden the tube inner surface. The relevant performance window is therefore a trade-off between melt flow and final burst strength retention.

Before extrusion of AMVO TLD from pellet form, the resin must be dried to a residual moisture content below 0.10% by weight, measured according to ISO 15512:2019. A desiccant dryer with a dew point of -40 °C or lower and a hopper setpoint of 80 °C is standard practice; residence times from 4 h to 8 h are common for cold, moisture-exposed material. Regrind streams should be limited to factory scrap and redried under the same conditions; mixtures with more than 30% regrind may show higher gel-particle counts and reduced burst pressure because prior thermal history increases oxidative degradation. Screw design for plasticized PA12 should avoid excessive shear heating: a single-screw extruder with L/D 25:1 to 30:1 and a 3:1 compression ratio is a suitable starting geometry, while high-shear barrier screws can accelerate plasticizer exudation and should be qualified with head-pressure trend monitoring.

Plasticizer Migration Kinetics and Low-Temperature Impact Response in PA12 Tubing

Plasticizer loss in PA12 tubing is governed by diffusion through the amorphous phase and by surface evaporation at elevated service temperatures. For AMVO TLD, continuous exposure to hot diesel or biodiesel blends increases the extraction rate because aliphatic esters and polar fuel components interact with the plasticized amorphous region. The practical consequence is a gradual increase in flexural modulus and a loss of elongation after long-term fuel contact. Low-temperature impact behavior is characterized by notched Charpy impact under ISO 179-1:2020 at -30 °C; plasticized PA12 grades generally retain higher impact energy at sub-zero temperatures than unplasticized PA12, but aged specimens can lose part of this advantage after plasticizer extraction. Compared with PA11, PA12 provides lower amide-group density, which yields lower equilibrium moisture uptake under ISO 62:2008 at 50% relative humidity and better retention of mechanical and electrical properties in humid environments. Differences from flexible PA12 copolymers are more subtle: copolymers can have lower Shore D hardness and better freeze resistance, but AMVO TLD is positioned for tube extrusion with tighter diameter and melt-strength control.

In chemical resistance evaluations, AMVO TLD inherits the aliphatic hydrocarbon resistance of PA12; diesel, mineral oil, and zinc chloride-free automotive coolants are generally within the acceptable service envelope. The grade is not intended for contact with concentrated strong acids, phenols, or oxidizing media. Environmental stress cracking in the presence of concentrated zinc chloride solutions is a known limitation for polyamide 12 and must be evaluated for a specific tube geometry under end-use conditions; published data for this exact AMVO TLD configuration is limited. For compliance documentation, the product is assessed under the European chemical inventory rules of Regulation (EC) No 1907/2006 and, where electrical or electronic equipment scope applies, Directive 2011/65/EU as amended by (EU) 2015/863. The supplier safety data sheet remains the controlling document for hazard communication.

Extrusion Melt Temperature Deviations Above 250 °C Accelerate Plasticizer Volatility and Calibration Instability.

If melt temperature is allowed to drift above 250 °C, the vapor pressure of the plasticizer increases and volatile material condenses on downstream calibrators. The result is an intermittent drag on the tube surface that changes outer diameter and gloss. On production lines, a die-temperature deviation of ±5 °C from an optimized setpoint is sufficient to produce visible sharkskin in tubes with wall thickness below 1 mm and to increase tube ovality. Below the recommended melt-temperature boundary, head pressure destabilizes because the elongational viscosity of the plasticized melt rises; the screw may operate in a feed-limited mode, and output fluctuates. These conditions favor a narrow processing window rather than broad latitude, and barrel-zone setpoints should be established with a melt-temperature probe rather than by thermocouple setpoint alone. The processing window described above is a starting point and must be adjusted for individual extruder size, screw wear, and downstream haul-off speed.