EMS-Grivory Grilamid L 25 W 40 NZ is a polyamide 12 compound classified within the Grilamid L series as a plasticized, impact-modified, heat-stabilized type for injection molding and extrusion. The 25 viscosity class identifies the base molecular-weight range of the PA12 resin, while W 40 denotes the plasticizer/softness range and NZ denotes an impact-modified, nucleated formulation. The term Dry in the product data designation indicates that the physical-property sheet refers to test specimens or granules conditioned to a moisture content below 0.10 mass percent, not a permanent surface state. This grade is typically selected where low moisture uptake, low-temperature ductility, resistance to aliphatic hydrocarbons, and reduced density relative to PA6 or PA66 are required in functional components such as tubing, quick connectors, clips, cable sheathing, and pneumatic line parts.

Dry-as-molded density is commonly reported as 1.01 g/cm³ under ISO 1183-1. That value is lower than the typical 1.13–1.14 g/cm³ range for unreinforced PA66 and lower than most PA6 grades. Water absorption at saturation under ISO 62 is generally in the range of 1.0–1.5 mass percent, which is substantially below the 8–10 mass percent saturation range common for PA6. This lower equilibrium moisture uptake means the glass-transition-related modulus reduction in humid service is less severe than in short-chain aliphatic nylons. Tensile modulus at 23°C in the dry as-molded condition is typically between 1000 MPa and 1300 MPa when tested according to ISO 527-1/-2. Yield stress generally remains below 45 MPa, and elongation at break is usually above 50%, which reflects the plasticized, ductile response of the grade. Notched Charpy impact at 23°C under ISO 179-1/1eA is commonly reported above 30 kJ/m², with exact values depending on specimen conditioning, notch preparation, and current EMS-Grivory documentation revisions.

What Distinguishes the L 25 W 40 NZ Grade from Unmodified PA12?

Unmodified PA12 of the same viscosity class shows higher tensile modulus, higher hardness, and lower low-temperature flexibility. The W 40 plasticizer component reduces tensile modulus and hardness while raising strain at break and shifting ductile behavior to lower temperatures. The NZ impact-modifier and nucleant package restores notched impact resistance and accelerates crystallization during cooling. In comparison with a non-plasticized, non-impact-modified PA12, this grade exhibits lower heat deflection temperature under load, reduced continuous-use temperature capability, and a greater tendency for stress relaxation in press-fit joints. The compensating benefit is a lower probability of brittle fracture in snap-fit connectors, thin-wall clips, and cable clamps subjected to low-temperature impact. Compared with the less plasticized Grilamid L 25 W 20 family, the W 40 designation generally indicates lower hardness and higher elongation, but direct numeric comparisons should be obtained from current manufacturer datasheets because plasticizer content and modifier loading are not specified as fixed percentages in the public designation.

Thermal behavior follows the PA12 crystalline melting range. Melting temperature is normally between 174°C and 178°C under ISO 11357-1/-3. The dry glass transition of unmodified PA12 is near 45–50°C; plasticization shifts the dynamic mechanical damping peak lower, which improves flexibility but reduces the upper stiffness plateau. Heat deflection temperature at 1.8 MPa under ISO 75-1/-2 is generally below 60°C, while the 0.45 MPa deflection temperature is typically above 90°C. The coefficient of linear thermal expansion parallel to flow is commonly in the range of 10–15 × 10⁻⁵ K⁻¹ under ISO 11359-1/-2. Dimensional change after molding is controlled by post-crystallization, orientation release, and moisture absorption. PA12 exhibits lower volume swell than PA6 or PA66 at identical relative humidity because of the longer aliphatic chain between amide groups.

The values in the table are representative ranges compiled from publicly available datasheet summaries. They are not engineering specification limits. Conditioned values at 23°C and 50% relative humidity will show lower tensile modulus and higher notched impact because absorbed water acts as a plasticizer in the PA12 matrix. The dry as-molded values establish the demolding and processing baseline, not the upper boundary for service performance.

When the Dry Condition Is Not Maintained During Molding

PA12 has limited hygroscopicity compared with PA6 or PA66, but the dry-state requirement remains relevant because residual moisture influences melt processing and part morphology. If granulate moisture exceeds approximately 0.10 mass percent, steam generated during melting can cause melt pressure fluctuation, splay or silver streaks on molded surfaces, and hydrolytic chain scission at elevated temperature. The standard drying procedure is 4–8 h at 80°C in a desiccant dryer with a dew point of -30°C or lower, or equivalent vacuum drying. Residual moisture should be verified by ISO 15512 or Karl Fischer titration. Material exposed to ambient air above 60% RH for extended periods should be re-dried before processing. The drying temperature should not be raised above 100°C for this plasticized grade because extended exposure to hot dry air can accelerate plasticizer migration to the granule surface and produce tacky or oxidized feed behavior.

When the melt temperature exceeds 260°C, the combined effect of residual moisture and shear heating can reduce viscosity enough to cause screw slippage, shot-weight variation, and gas generation. On injection molding machines with general-purpose three-zone screws, melt temperature should be maintained between 230°C and 250°C. A processing window of ±5°C is recommended for thin-wall connectors because freeze-off occurs at the low end while surface blush and plasticizer volatilization occur at the high end. If hot-runner manifolds are used, residence time at manifold temperature should not exceed 10 minutes. Mold cavity venting with land depth in the 0.01–0.03 mm range is required to remove low-molecular-weight volatiles. Tool surfaces should be corrosion-resistant because the slightly acidic volatiles from overheated polyamide can attack unprotected steel over repeated cycles.

Extrusion of this grade for tubing and cable sheathing is normally performed on single-screw machines with L/D 24–36 and compression ratios in the polyolefin range. Zone temperatures are typically set from 220°C at the feed section to 250°C at the die. A breaker plate with 40–60 mesh screen pack is generally adequate because the compound is unfilled and does not require high-shear filtration. Melt pressure before the die should remain below 250 bar to limit shear heating. In vacuum sizing, rapid quenching improves surface quality but increases line tension and orientation. For thin-wall pneumatic tube, a draw-down ratio below 2:1 and vacuum levels of 0.2–0.4 bar are common starting points, but actual parameters depend on die geometry, haul-off speed, and downstream diameter control.

Chemical resistance follows the expected PA12 profile. The material resists aliphatic hydrocarbons, mineral oils, greases, and common automotive coolants. It is not resistant to concentrated mineral acids, formic acid, or strong oxidizing media at elevated temperature. Stress-crack resistance in zinc chloride solution, often used as a PA12 quality indicator, can be reduced by plasticizer content because the plasticized matrix has a lower strain threshold for craze initiation. Published data for this specific compound under ISO 22088-2 or OEM-specific stress-crack tests is limited; qualification should therefore be performed on the final tube or connector geometry rather than on the base resin alone.

Regulatory Status and Compliance Documentation

The grade is typically supplied with documentation covering food-contact and industrial regulatory frameworks. PA12 resins may be evaluated under FDA 21 CFR 177.1500 for nylon resins, subject to end-use limitations and migration testing. European food-contact compliance may be assessed under EU Regulation (EU) No 10/2011 with the relevant overall migration limit of 10 mg/dm². The product is generally subject to REACH registration under Regulation (EC) No 1907/2006 and should be evaluated against the candidate list of substances of very high concern. Electrical and electronic applications should be checked against Directive 2011/65/EU for RoHS-restricted substances. These statements are not a substitute for current supplier certificates because regulatory status changes with country-specific requirements and application-specific migration or extraction testing.

The continuous-use temperature should be established for the specific load and environment. At continuous exposure above 100°C in dry conditions, plasticizer migration or evaporation can increase hardness and reduce low-temperature impact over time. For underhood components, local air temperature above 125°C should be avoided unless validated by OEM thermal-aging protocols. Combination with aggressive flame-retardant additives, chlorinated solvents, or highly alkaline coolant concentrates is not recommended because these agents can degrade the PA12 backbone or extract the plasticizer. Molded parts intended for precision dimensional applications should be conditioned or annealed to stabilize post-molding shrinkage; PA12 crystallizes over time, and the nucleated formulation reduces but does not eliminate this drift.

On production-scale twin-screw extrusion lines with L/D 30–36, moisture above 0.15 mass percent commonly appears as melt pressure instability at the die and periodic tube wall-thickness variation. The nucleated package shortens crystallization time, which can reduce cycle time in injection molding but also requires that cooling channels be placed close to the cavity surface. If the mold temperature is too low, below approximately 40°C, the material may freeze before full crystallinity develops, producing a softer surface and lower dimensional stability after demolding. If the mold temperature is too high, above 80°C, cycle time increases and ejection marks may occur because the plasticized matrix has lower hot rigidity. A mold temperature between 50°C and 70°C is therefore a practical starting range for many technical parts.