EMS-Grivory Grilamid L 16 GM nat Nylon 12, Dry is supplied as a natural-coloured, glass-fibre-reinforced polyamide 12 compound. The grade is formulated for injection moulding of dimensionally stable technical parts in automotive fluid handling, compressed air systems, cable management, and industrial snap-fit assemblies. The Dry designation indicates moisture-controlled packaging with a maximum residual moisture content of 0.10% by mass at the point of dispatch. Under ISO 1043 nomenclature, the material is classified as PA12-GF30; the GM suffix identifies the glass-fibre reinforcement package, L 16 identifies the viscosity class of the polyamide 12 matrix, and nat designates natural or uncoloured resin. Representative dry-as-moulded values include density of 1.24 g/cm³ per ISO 1183-1, tensile modulus of 5000 MPa per ISO 527-1/-2, and Charpy notched impact strength of 8 kJ/m² per ISO 179/1eA. These values are typical manufacturer data and should be verified against the current EMS-Grivory technical datasheet for lot-specific certification.

Material identity and conditioning criteria

The polymer matrix is produced from laurolactam, giving the aliphatic chain structure that distinguishes polyamide 12 from the shorter-chain polyamide 6 and polyamide 66 families. This chemical structure reduces the equilibrium moisture uptake and improves dimensional stability in humid service. The glass-fibre content is nominally 30% by mass and is verified by ash content testing under ISO 3451-1. Because the glass fibre mass does not absorb water in the same manner as the polyamide matrix, the reinforced grade displays lower saturated water uptake than unreinforced polyamide 12. The natural formulation contains no added pigment package, which permits in-house colouring but requires the processor to control colourant compatibility and drying discipline. The dry state is a processing prerequisite rather than a storage convenience: residual moisture above 0.10% can hydrolyse amide linkages during melt residence, reduce molecular weight, and create surface defects such as silver streaking. The product is supplied in foil-lined, moisture-barrier packaging with desiccant indicators. Once the original packaging is opened, ambient humidity can increase the surface moisture content of pellets within hours. For production lines operating at sustained throughput, a dry-air hopper system with a dew point of at least -30 °C is typically specified.

How does dry-state handling alter the processing window?

Pre-drying is not required when the moisture-barrier packaging remains undamaged and the material is consumed directly from a sealed hopper. If intermediate storage exceeds 2 h at 23 °C and 50% relative humidity, or when handling occurs above 60% relative humidity, desiccant drying at 80 °C for 4 h to 8 h is recommended. Drying temperature should not exceed 90 °C because prolonged residence at elevated temperature in the presence of oxygen can induce yellowing and molecular weight loss. The target residual moisture before melting is below 0.10%. Melt processing should use a barrel temperature profile of 240 °C to 270 °C, with the front zone not exceeding 280 °C. A reverse temperature profile, in which the first barrel zone is set 10 °C to 20 °C lower than the feed zone, may be used to reduce fibre attrition and control melt temperature when screw recovery is long. Mould temperature should be set between 60 °C and 100 °C. For thin-walled parts below 1.5 mm, the upper half of this range improves crystallinity and surface appearance but extends cycle time. For thick sections above 3 mm, lower mould temperatures reduce cycle time but increase shrinkage variance and may raise internal stress.

On production-scale machinery, the compound should be processed with a general-purpose three-zone screw having an L/D ratio between 18:1 and 25:1 and a low compression ratio of 1.5:1 to 2.0:1. Excessive shear from high compression screws reduces glass fibre length and lowers notched impact strength. Shot size should remain between 30% and 70% of barrel capacity to limit residence time; maximum continuous residence time at melt temperature should not exceed 10 min, and shorter residence is required above 270 °C. Injection speeds of 50 mm/s to 100 mm/s for medium wall sections are typical, with hold pressures from 40 MPa to 80 MPa depending on gate geometry and wall thickness. Fibre orientation along flow paths creates anisotropic shrinkage: published mould shrinkage values are approximately 0.1% to 0.3% in the flow direction and 0.4% to 0.7% transverse. Actual shrinkage depends on gate type, wall thickness, and processing parameters. Weld lines in glass-reinforced PA12 can retain 50% to 70% of the base tensile strength when formed at high mould temperatures; design validation should include weld-line specimens under production conditions.

When glass fibre loading shifts the PA12 property envelope

Compared with unreinforced Grilamid L 16, the 30% glass-fibre reinforcement increases tensile modulus from approximately 1100 MPa to 5000 MPa and raises the heat deflection temperature under 1.8 MPa from approximately 50 °C to 160 °C. Elongation at break falls from unreinforced values above 50% to approximately 4%, indicating that the reinforced grade is stiffness-limited rather than ductility-limited. This shift is not linear with fibre content; it reflects fibre-matrix adhesion and the fibre length distribution produced during compounding. The tensile modulus is measured under ISO 527-1/-2 at 1 mm/min. Flexural modulus is typically higher than tensile modulus in short-glass systems because of the differing stress distributions; comparative design calculations should therefore use the tensile secant modulus at the service strain rather than the initial flexural value. Creep response at 23 °C under continuous stress is more favourable than unreinforced polyamide 12, but the material remains viscoelastic and requires time-dependent creep data for long-term structural analysis.

Low-moisture performance under ISO 62 equilibrium conditions

Under ISO 62 saturation conditions, unreinforced polyamide 12 absorbs approximately 1.1% water by mass; the glass-reinforced grade is lower because the fibre fraction contributes little to water uptake. Glass-reinforced polyamide 6 and polyamide 66 grades at comparable fibre content can exhibit saturation values of 4% to 6%, depending on formulation and conditioning temperature. This difference affects swelling, electrical insulation, and modulus retention in humid environments. The PA12 grade retains a larger proportion of dry tensile modulus at 50% relative humidity equilibrium than short-chain polyamides. In addition, polyamide 12 processes at lower temperatures, typically 240 °C to 270 °C, compared with 260 °C to 290 °C for glass-filled PA6 and 280 °C to 310 °C for glass-filled PA66. This reduces thermal degradation risk and energy consumption, but the grade correspondingly has lower heat deflection temperature and lower continuous-use temperature. Chemical resistance to automotive coolants, oils, greases, aliphatic hydrocarbons, and salt sprays is generally acceptable under ISO 175 immersion testing, but strong mineral acids, phenols, oxidising agents, and prolonged hot water above 80 °C are outside the recommended service envelope. Material selection should include immersion tests in the actual service fluid under expected temperature and stress.

Typical production applications include compressed-air connectors, cable conduits, protective coil tubing, automotive fuel-vapour valves, sensor housings, and snap-fit brackets. The combination of low moisture uptake and moderate stiffness is appropriate for parts with tight tolerances exposed to varying humidity. For applications requiring continuous exposure to hydrolytic conditions above 80 °C, alternative polyphenylene sulphide, polyphthalamide, or stabilised PA66 grades may be more suitable. In fuel-vapour applications, glass-reinforced polyamide 12 can be used where low permeation is not the sole critical requirement, but component-level permeation testing under the relevant OEM or ISO standard is required. Published data for specific fuel permeation rates of this exact grade is limited; component validation should be performed under the final wall thickness and service temperature.

In hot-wet and additive-bearing environments, processing boundaries tighten

The compound is not inherently flame retardant; standard glass-filled polyamide 12 grades typically hold an HB rating under UL 94. Flame-retardant variants require modified formulations. Addition of recycled regrind should be limited to 20% maximum to maintain fibre length distribution and impact properties, and regrind must be dried to the same residual moisture target as virgin material. Combination with acid-releasing masterbatches, halogenated flame retardants, or amine-based heat stabilisers may cause matrix degradation or surface deposits; compatibility must be tested under production conditions. For outdoor ultraviolet exposure, the natural grade requires carbon black or hindered amine light stabiliser addition unless the part is used indoors. Published data for long-term UV ageing of this exact grade is limited; design validation should include ISO 4892-2 weathering cycles for exterior-facing applications. Mould design should include uniform wall thickness transitions and polished runner systems to reduce shear heating. For multi-cavity tools, tab gate diameters between 0.8 mm and 2.0 mm are typical; hot-runner selection should use externally heated manifolds with fibre-compatible torpedo tips. Venting depth of 0.01 mm to 0.02 mm is recommended to allow gas escape without flash. Because the melt is less aggressive than polyamide 6 or polyamide 66, standard corrosion-resistant tool steels may be adequate for low-volume production, but hard chrome or nitrided surfaces may still be used for extended tool life.

Lot-to-lot verification and regulatory documentation

Manufacturing consistency is typically monitored through melt volume-flow rate under ISO 1133-1, ash content under ISO 3451-1, moisture content by Karl Fischer titration under ISO 15512, and tensile specimen testing under ISO 527-1/-2. The material is supplied with batch certificates that should be retained for traceability. Regulatory documentation available from EMS-Grivory includes declarations of conformity to REACH and RoHS 2011/65/EU; current revision status must be confirmed before use in restricted applications. Food-contact and potable-water listings are grade-specific and require current manufacturer confirmation. No statement in this document substitutes for verified certification for medical, aerospace, or safety-critical components.

Capillary rheometry under ISO 11443 shows that glass-filled polyamide 12 exhibits shear-thinning behaviour; melt viscosity at 270 °C and 1000 s⁻¹ is typically lower than glass-filled polyamide 66 at its processing temperature, resulting in lower injection pressure for equivalent flow length. Mould-filling simulation requires pressure-volume-temperature data and fibre orientation tensors. Generic PA12-GF30 simulation datasets should be calibrated against short-shot studies on the production tool. Mould temperatures above 80 °C reduce the frozen-layer thickness and promote more uniform fibre orientation across the wall. Electrical insulating behaviour is improved by low moisture uptake. Comparative testing on dry-as-moulded and conditioned specimens shows that relative permittivity and dissipation factor change less for PA12-GF30 than for PA6-GF30 after 24 h at 23 °C and 50% relative humidity. Dielectric strength under IEC 60243 should be measured on conditioned samples because surface moisture can reduce breakdown voltage.