EMS-Grivory Grilamid L XE 10953 black Nylon 12, Dry is classified under ISO 1043-1 as PA12, an aliphatic semicrystalline polyamide produced from laurolactam or ω-aminododecanoic acid. The grade identifier combines the Grilamid L polymer family with a black pigmentation and stabilization package; the supplier’s public product nomenclature does not disclose the complete additive recipe, so additive-specific performance claims must be verified against the current EMS-Grivory technical datasheet. Data reported for the dry condition are generated after specimen conditioning according to ISO 1110, where moisture content is reduced below 0.10 wt% and tested within the specified time window. In this condition, unfilled PA12 typically shows a density of 1.01 g/cm³ when measured by ISO 1183-1, which is lower than PA6 or PA66 densities near 1.14 g/cm³. The low amide-group concentration of PA12 produces saturation water absorption near 1.5% under ISO 62 at 23°C in water, compared with 8.5–9.5% for PA6 and PA66. This moisture uptake difference is a central factor in the material’s dimensional stability in humid service environments.

The dry-state property envelope for unfilled PA12 also includes a Vicat softening temperature near 140–150 °C under ISO 306. Coefficient of linear thermal expansion in the flow direction is approximately 110–120 × 10⁻⁶ K⁻¹ by ISO 11359-2. For electrical components, dry PA12 has volume resistivity above 10¹³ Ω·m by IEC 62631-3-1; dielectric strength is commonly 25–30 kV/mm under IEC 60243-1. These values change as moisture content rises, so electrical insulation systems must be tested at the service humidity range.

Because this is a dry-state product designation, the delivered pellet moisture content depends on packaging, storage conditions, and time after opening. The dry suffix does not eliminate the need for pre-processing drying; it denotes that the reported mechanical data are from dry-as-molded test specimens rather than conditioned specimens. A sealed aluminum barrier bag with desiccant is standard for shipment, and any bag opened for more than 30 min at 23°C/50% RH begins to re-adsorb atmospheric moisture. In a production line, pellets transferred from the bag to an open hopper should be protected by a dry-air purge or consumed within a single shift unless validated for longer open times by ISO 15512 moisture measurement.

What separates this grade from commodity PA12 and short-chain aliphatic polyamides?

At melt-state processing temperatures, the grade shows a PA12 melting peak in the range 174–178 °C by ISO 11357-1/-3; extrusion typically operates from 210 °C to 250 °C, and injection molding from 230 °C to 270 °C. The upper processing limit is 280 °C; above this temperature, thermo-oxidative chain scission accelerates and produces discoloration, volatile evolution, and molecular weight loss. Compared with short-chain polyamides such as PA6 or PA66, the longer C12 aliphatic repeat unit reduces the frequency of amide linkages, which lowers melting point, water affinity, and dry-state stiffness. For unfilled dry PA12, tensile modulus is normally in the 1500–1700 MPa range under ISO 527-1/-2, whereas dry PA6 and PA66 typically exhibit 3000–3600 MPa. The trade-off is lower stiffness and lower continuous-use temperature; unmodified PA12 is generally not specified for continuous service above 120 °C in air without oxidative stabilization validation.

In pneumatic control lines and automotive air-brake tubing, PA12 compounds are frequently qualified to SAE J844 and ISO 7628 for burst strength, boil-point retention, and low-temperature impact after heat aging. The low saturated water absorption of PA12 reduces fitting retention changes when humidity shifts; at 23°C/50% RH, equilibrium moisture uptake for PA12 is approximately 0.7 wt% under ISO 62, while PA6 and PA66 absorb 2.5–3.0 wt%. The use of the black compounded grade in cable jackets and outdoor conduits requires ultraviolet stabilization data from the supplier; published data for the exact XE 10953 additive package under long-term UV exposure is limited, and outdoor service life must be validated by ISO 4892-2 or equivalent weathering protocol.

Drying, residence time, and melt-temperature thresholds

Moisture control is the primary process variable. On single-screw extruders with 24:1 to 30:1 L/D and three-zone screws, undried PA12 pellets exposed to ambient air above 60% RH can regain sufficient water within 30–60 min to produce silver streaks, foam nucleations, and screw torque instability. A desiccant dryer with dew point at or below -40 °C, air flow of 1.5–2.0 m³/h per kg/h throughput, and residence time of 4–6 h at 80 °C is required to reach ≤0.10 wt% moisture by ISO 15512. For twin-screw compounding of regrind or concentrate dilution, barrels with 32:1 to 44:1 L/D, vented zones, and melt-temperature sensors at the gate are used; vacuum venting at −0.08 MPa minimum avoids hydrolysis and trapped volatiles. Processing above 280 °C or melt residence times beyond 10 min above 260 °C causes chain scission and viscosity drift, visible as yellowing, black specks, and inconsistent tubing ovality. Injection molding requires screw-back pressure of 2–5 MPa, shot sizes of 30–70% of barrel capacity, and mold temperatures from 40 °C to 80 °C; mold temperature is adjusted within this range to balance crystallinity against ejection force and post-mold shrinkage.

Melt volume-flow rate for dry PA12 grades is typically measured by ISO 1133-1:2022 at 275 °C/5 kg. Supplier-specific MVR values are required for screw speed and injection pressure calculations. In practice, PA12 demonstrates shear-thinning behavior over the shear-rate range of 100–10,000 s⁻¹ encountered in capillary and injection molding dies; apparent viscosity drops significantly as shear rate rises, which assists thin-wall filling but increases the risk of jetting if gate speeds exceed design limits. Shear heating in hot-runner systems must be limited to avoid local melt temperature above 280 °C; hot-runner thermocouples should be installed within 10 mm of the gate and controlled to ±3 °C to prevent material stagnation.

Hot-plate welding, laser welding, and ultrasonic welding require dry surfaces and specific joint designs. Black pigmentation can interfere with laser transmission if through-transmission welding is attempted; in such cases the black grade is used as the absorbing layer and a natural or laser-transparent PA12 layer is required. The dry condition maximizes weld strength, but reabsorbed surface moisture above 0.10 wt% can reduce weld-line strength by hydrolysis at the interface. Joint qualification is commonly performed by tensile testing across the weld under ISO 527-1/-2 or by pressure or burst testing of welded tubing assemblies to ISO 7628. For adhesive bonding, surface preparation with an alcohol wipe is insufficient for structural bonds; corona, plasma, or primer treatments are required because PA12 has low surface energy and the black grade may contain processing aids and stabilizers that migrate to the surface over time.

When PA12 substitutes for PA6 or PA66 in dimensionally stable connectors and tubing

Two performance boundaries must be evaluated: stiffness and thermal resistance. For connectors and clips that rely on snap-fit retention, replacing PA66 with dry PA12 lowers tensile modulus from approximately 3300 MPa to 1600 MPa under ISO 527-1/-2, requiring thicker section walls or modified geometry to maintain insertion and retention force. Conversely, the moisture-conditioned modulus of PA12 remains closer to its dry value than PA6 or PA66; this reduces the seasonally dependent engagement force in humid environments. For tubing applications, PA12 offers lower extractables and better zinc-chloride resistance than PA6, which is relevant in automotive brake-line and pneumatic-line service. The grade is evaluated for fuel vapor permeability under ISO 15105 or SAE J1737 when used as a barrier layer; unmodified PA12 alone has higher hydrocarbon permeation than EVOH or semi-aromatic polyamide, so a multilayer coextrusion with an EVOH barrier is often required for low-permeation fuel systems.

Nominal values for unfilled dry specimens; the black XE 10953 compound may vary within supplier tolerance and must be confirmed against the grade-specific datasheet.

Moisture conditioning alters stiffness, ductility, and dimensional response

Polyamide 12 reaches equilibrium moisture content near 0.7 wt% at 23°C/50% RH and 1.5 wt% in water saturation; conditioned specimens show a modulus reduction of roughly 10–20% and an increase in notched Charpy impact energy when tested under ISO 179-1/1eA. This property shift is smaller than for PA6 or PA66, but it must be included in finite-element simulations and tolerance stack calculations. For parts machined or assembled in the dry condition, subsequent water absorption increases dimensions by approximately 0.1–0.3% from dry to 50% RH depending on wall thickness and crystallinity. Calculation of dimensional change should use moisture expansion data measured by ISO 62 and thermomechanical analysis, not linear thermal expansion alone.

Chemical resistance is evaluated by mass and volume change plus tensile retention after immersion according to ISO 175 or stress-cracking exposure under ISO 22088-2 and ISO 22088-3. PA12 is resistant to aliphatic hydrocarbons, automotive fuels, diesel, greases, and zinc chloride solutions at ambient temperature, but it is attacked by strong mineral acids, phenols, formic acid, and oxidizing agents. The black grade may show earlier crack initiation if the pigment package creates surface stress concentrations, so validation on actual molded or extruded surfaces is required. Avoid continuous contact with concentrated hydrochloric acid at temperatures above 40 °C and with methanol at temperatures above 60 °C unless specific compatibility data are available; published data for this exact black compound under these exposures is limited.

Field audits on tubing extrusion lines show that black PA12 grades have two recurring batch-related failure modes: pellet fines and carbon-black agglomerates. Fines generation during conveying increases dust accumulation in vacuum receivers and can cause feed-bridge over the extruder throat. Carbon-black dispersion levels should be checked by pressure-rise filtration or by extruded film optical microscopy; agglomerates larger than 20 µm can initiate surface defects in thin-wall tubes and cause pinhole rejection in high-speed cable jacket lines. A melt pump upstream of the die reduces pressure variation and stabilizes wall thickness to ±0.05 mm on tubing lines running at 50–150 m/min.

Production planning should treat the dry grade as shear-sensitive and moisture-sensitive. Regrind from sprues, runners, and rejected parts can be reused at 20–30 wt% in noncritical components if the regrind is dried to ≤0.10 wt% moisture and screened for contamination; each regrind pass shifts melt volume-flow rate upward under ISO 1133-1:2022 and lowers elongation at break under ISO 527-1/-2. Above 30 wt% regrind, qualification batches should be tested for Charpy impact, tensile elongation, and MVR before release. Regulatory documentation for REACH SVHC, RoHS 2011/65/EU, and food-contact suitability must be requested from EMS-Grivory for the specific batch and color code because black pigment and processing stabilizers can affect migration limits under EU 10/2011 or 21 CFR 177.1500. For drinking-water contact, the grade must not be assumed compliant unless the supplier has issued a formulation-specific approval.