EMS-Grivory Grilamid XE 3926 black 9992 PA12 is an impact-modified, flexibilized polyamide 12 supplied as a black pellet for injection molding and profile extrusion. The base polymer is a laurolactam-based PA12, and the lower amide-group density relative to PA6 and PA66 reduces equilibrium moisture uptake. The grade is identified in the EMS-GRIVORY product line as Grilamid XE 3926, with “black 9992” denoting the carbon-black-containing color formulation. Published datasheet values include a density of 1.01 g/cm³ under ISO 1183-1, saturated water absorption near 1.4 % under ISO 62, and a melting peak near 176 °C at 10 K/min under ISO 11357-1/-3. Dry-state tensile modulus is reported in the range of 250 to 400 MPa under ISO 527-1/-2, placing the material below a standard unplasticized PA12 and well below glass-reinforced PA12. The black 9992 package provides opacity and ultraviolet screening, but the carbon black also raises melt viscosity slightly relative to natural grades and reduces contrast in laser-marking processes.

What Separates an Impact-Modified PA12 from Standard PA12 and PA66?

A rigid unplasticized PA12 typically exhibits dry tensile modulus near 1400 MPa and Shore D hardness near 70; Grilamid XE 3926 black 9992 is formulated to operate at roughly one-fourth to one-fifth of that modulus. Under ISO 527-1/-2, yield stress is reported at approximately 16 MPa, and nominal strain at break exceeds 50 %. Charpy unnotched specimens tested under ISO 179-1/1eU do not break at 23 °C or -30 °C. Shore D hardness is reported near 46 under ISO 868. Compared with PA66, the PA12 backbone reduces saturated water uptake from approximately 8.5 % to roughly 1.4 %, which lowers hygroscopic dimensional change but also limits elevated-temperature load-bearing. Heat deflection temperature under 1.80 MPa is approximately 45 °C under ISO 75-1/-2. Continuous structural use above that boundary is therefore restricted, and the material is not a direct substitute for heat-stabilized PA66 or glass-reinforced PA12 in hot load-bearing brackets.

Pre-drying in a closed-loop dehumidified-air hopper dryer at a resin temperature of 80 °C for 4 to 6 h is applied before injection molding. The dryer outlet dew-point target is -40 °C or lower, and residual moisture is verified below 0.10 wt% by Karl Fischer titration or a calibrated moisture analyzer. In thin-wall electrical-clip tools running on a 600 kN hydraulic clamp machine, melt temperature is held between 220 and 250 °C, and mold temperature is maintained between 40 and 80 °C depending on required surface replication. A general-purpose screw with 20 L/D and compression ratio near 2.5:1 is usually adequate, with hydraulic back pressure of 5 to 15 bar supporting melt homogeneity. Mold venting below 0.02 mm land depth has been associated with gate blush and burn marks at high injection speed, especially in multi-cavity tools with runner diameters below 4 mm. Shrinkage for unreinforced PA12 is anisotropic and is typically observed between 0.7 % and 1.5 % under ISO 294-4, requiring cavity-by-cavity compensation rather than a single global scaling factor.

When Black 9992 Carbon Black Is Required for UV Resistance in Outdoor Connector and Fluid-Line Components

Black 9992 contains carbon black, which absorbs ultraviolet radiation and reduces photo-oxidative chain scission in exposed PA12 surfaces. For outdoor connector housings, cable clamps, and flexing clips, this color package delays surface chalking, loss of impact, and discoloration. Published data for this specific compound under long-term weathering is limited; acceptance testing is usually performed under ISO 4892-2 xenon-arc conditions with irradiance of 0.51 W/m² at 340 nm, followed by color change and Charpy notched impact verification under ISO 179-1/1eA. The PA12 chemistry provides resistance to aliphatic hydrocarbons, oils, greases, and many hydraulic fluids at moderate temperatures. However, continuous exposure to strong acids, phenols, or hot water above 80 °C can hydrolyze amide bonds and should be excluded. This grade is not a replacement for fluoropolymers or high-temperature chemically resistant resins in hot strong-acid service.

On production-scale profile extrusion for cable conduits and pneumatic tubing, the grade is processed through a single-screw extruder with a barrier screw and 30:1 L/D, using screen packs of 60/80/100 mesh. Melt temperature at the breaker plate is held below 260 °C, and residence time is kept under 10 min to limit thermal degradation and black speck formation. Water calibration at 20 to 40 °C is used for dimensional control; PA12 absorbs less water than PA6, reducing post-extrusion diameter drift during humid storage. In flexible tube applications, the low modulus of XE 3926 permits tighter bend radii than unplasticized PA12, but kinking resistance must be verified by mandrel-bend testing because the published datasheet does not define a universal minimum bend radius for all wall thicknesses.

Drying, Dew-Point Control, and Residence-Time Limits in High-Shear Extrusion

The dominant processing boundary is residual moisture. PA12 is less hygroscopic than PA6 or PA66, but water concentrations above 0.10 wt% at melt temperatures above 220 °C promote hydrolysis. On a 25-mm twin-screw compounding extruder with 40:1 L/D, moisture-related degradation appears as reduced die-head melt pressure and a shift in melt volume-flow rate outside the incoming QC range. Dryer hoppers should maintain a dew point of -40 °C or lower, and inlet air should not exceed 90 °C to prevent pellet oxidation and yellowing. Regrind fractions up to 30 % are used only after drying and melt-flow verification under ISO 1133-1; higher regrind fractions can lower Charpy unnotched values and shift part shrinkage. Shutdown purges with low-viscosity PA12 or a dedicated purge compound are recommended. The grade is incompatible with amine-containing masterbatches that accelerate oxidative degradation; only PA12-compatible color and additive concentrates are added at 2 to 4 wt%.

If Hot-Water, Strong-Acid, or Continuous-Load Service Is Planned

Automotive cable-clip and fuel-line retention applications use the no-break Charpy behavior at -30 °C and the low saturated water uptake. In clips mounted near transmission-tunnel surfaces, peak service temperature is typically kept below 80 °C; at higher metal-contact temperatures, the heat deflection temperature of 45 °C at 1.80 MPa becomes the limiting factor. Resistance to zinc-chloride road salt and common under-hood oils is evaluated according to ISO 1817 or internal EMS-GRIVORY immersion protocols; published third-party data for every fluid combination is limited, so compatibility testing at production temperature and stress is required before series release. This PA12 grade is not recommended for hot-water pressure vessels, continuous strong-acid immersion, or load-bearing parts operating above its HDT/A boundary.