EMS-Grivory Grilamid® LV-50H FWA black 9225 is a 50% by weight glass-fibre-reinforced polyamide 12 injection-moulding compound. Under ISO 1874-1 the base designation is PA12-GF50. The LV prefix identifies a low-viscosity moulding grade within the Grilamid L series; the H suffix indicates heat stabilisation; FWA is a supplier-specific regulatory qualifier for grades positioned in food-contact and drinking-water component evaluations; black 9225 is the colour code. Moulded articles may be marked with the material identification PA12-GF50 according to ISO 11469.

The compound is supplied as black pellets in moisture-protective packaging. Density is 1.52 g/cm³ when measured to ISO 1183-1. The 50% glass fraction raises density above unfilled polyamide 12 and reduces the resin fraction available for moisture sorption. Water absorption at saturation to ISO 62 is 0.15%; unfilled PA12 grades typically absorb on the order of 1.5% under the same standard. This lower moisture uptake supports dimensional stability in water-contact components but does not eliminate moisture-related dimensional change.

Because glass fibre length distribution and coupling agent concentration influence tensile modulus and impact, incoming-lot verification commonly includes ash content by ISO 3451-1 and melt-flow or solution-viscosity measurement. A shift in pellet bulk density of more than ±0.03 g/cm³ indicates possible fibre-loading variation and justifies a property screen before moulding.

Values in the table are manufacturer-published typical data for the black 9225 formulation; they are not specification limits. Conditioned values refer to equilibrium at 23°C and 50% relative humidity unless otherwise noted. The dry and conditioned tensile modulus difference is much smaller than that of unfilled polyamide 12 because the glass fibre network carries a large share of the applied load. The same mechanism reduces the moisture-induced loss in HDT and creep resistance, but it does not eliminate fibre-matrix debonding over long-term hydrothermal exposure.

Thermal analysis by ISO 11357-1/-3 gives a melting point of 178°C. HDT/A at 1.8 MPa to ISO 75-1/-2 is 160°C. Continuous load-bearing design should not exceed the HDT/A limit unless specific creep-rupture testing is performed. The grade is not flame-retarded; the published classification is UL 94 HB at 0.8 mm under IEC 60695-11-10. Electrical volume resistivity is typical of glass-filled polyamide and is in the high-insulation range; however the grade is not designed for high-voltage insulation after long-term water exposure. Surface resistivity and comparative tracking index should be verified by IEC 62631-3-1, IEC 62631-3-2, and IEC 60112 if used in electrical enclosures or switchgear housings.

Creep and fatigue data for the black 9225 configuration are not fully published; application engineers should generate specific creep-rupture curves under ISO 899-1 or ISO 527-1 tensile loading. At stress levels above 60% of tensile stress at break, glass-filled polyamides can show a steeper creep-rupture slope than unfilled grades because matrix craze at fibre ends accelerates damage accumulation.

The black 9225 pigment is integrated as a formulated colour rather than added as a masterbatch at the machine; this distinction is important for regulatory and mechanical consistency. Natural-grade mechanical data are not automatically identical to black 9225, although supplier-controlled black lots are held to the same specification window. If colour is critical for laser welding or marking, the laser-additive package should be confirmed with EMS because carbon black can absorb laser energy differently than non-black grades.

What distinguishes 50% glass-filled PA12 from 30% glass-loaded and unfilled grades?

At 50% glass loading, the dry tensile modulus is approximately 13,500 MPa to ISO 527-1/-2. A 30% glass-reinforced PA12 typically falls near 8,000–9,000 MPa, and unfilled PA12 is generally below 2,000 MPa depending on moisture. The stiffness increase is accompanied by a reduction in dry elongation at break to approximately 3%, compared with higher ductility in lower-filled and unfilled polyamides. This grade is therefore specified for rigid housings, brackets, and fluid-pressure containment rather than snap-fit features that require large post-yield deformation.

Fibre orientation makes shrinkage and thermal expansion anisotropic. Unfilled PA12 commonly has published CLTE values in the 100–120 ppm/K range. In LV-50H FWA black 9225, manufacturer data indicate approximately 20 ppm/K parallel to flow and 60 ppm/K transverse to flow under ISO 11359-2. Tooling shrinkage measured to ISO 294-4 is approximately 0.1% longitudinal and 0.2% transverse. These values are initial tooling inputs; gate geometry, packing pressure, mould temperature, and flow length shift the effective shrinkage in production. On a 100 mm dimension, a 0.1 percentage point differential between parallel and transverse shrinkage can create 0.1 mm of relative movement if orientation varies.

Compared with PA12-GF30, the 50% glass variant increases melt viscosity and injection-pressure demand. The LV designation partly offsets this by reducing molecular-weight-controlled viscosity, but the filled melt remains more viscous than unfilled PA12. Thin walls below 1.0 mm should be evaluated by mould-filling simulation using supplier viscosity curves rather than generic polyamide data. The 50% glass grade also produces higher surface roughness and more visible fibre orientation at weld lines; mould textures specified according to VDI 3400 will not fully conceal glass read-through.

When melt temperature and residence time drift outside the supplier window

Drying is required when granulate has been exposed to ambient relative humidity above 60% or when the original desiccant barrier packaging is damaged. A desiccant dryer with a dew point of -40°C or lower is set to 80°C for 4–6 hours. The target residual moisture before feeding is below 0.10 wt%. If the material is processed above this moisture level, surface splay, nozzle drool, and hydrolytic molecular-weight reduction may be observed; the loss appears as reduced ISO 179-1/1eA notched impact and greater lot-to-lot variation in weld-line strength. If a machine hopper is charged with more than 30 minutes of production, desiccant-bed hopper drying is used rather than hot-air tray drying because the latter cannot reliably reach the required dew point.

At the nozzle, melt temperature is maintained between 220°C and 260°C. The lower limit is set by insufficient melt homogeneity at cold spots; the upper limit is set by thermo-oxidative chain scission. The 50% glass-filled melt is shear-thinning, and excessive injection speed can produce visible glass streaking at the gate. Moderate-to-high injection velocity with controlled fill time is used; back pressure is kept low enough to avoid excessive fibre attrition while still providing melt homogeneity. Screw configurations for 50% glass-filled polyamide conventionally use a compression ratio of 1.5:1 to 2.0:1 and wear-resistant coating along the metering section.

Mould temperature is maintained between 80°C and 100°C. Below 80°C, the part surface may develop a lower crystalline fraction, causing post-mould dimensional movement and lower HDT at the skin. Above 100°C, cycle time increases without a proportional stiffness benefit for most wall thicknesses. For pressure-boundary parts such as valve bodies, the mould temperature is kept at the upper end of the range to stabilise shrinkage and reduce frozen-in stress around inserts.

Residence time at melt temperatures above 250°C is limited to 6 minutes. If a machine stoppage exceeds 5 minutes, barrel temperatures are reduced to 180°C and the screw is run at low speed until the interruption clears. Long residence times produce thermal degradation that may not be visible as discolouration until mechanical properties have already declined. Weld-line strength is especially sensitive to degraded resin at the flow front.

The 50% glass reinforcement is abrasive. Production equipment should use wear-resistant screw barrels, bimetallic non-return valves, and hardened mould inserts. Steel hardness of at least HRC 55 is specified for gates, shut-offs, and hot-runner tips. Regrind addition above 20% by weight is to be validated by ISO 179-1/1eA and ISO 527-1/-2 because repeated plastication reduces fibre length distribution and lowers notched impact and tensile strength.

Applications are concentrated in water-carrying and food-contact environments where dimensional stability and low water uptake are required. Candidate parts include water-meter bodies, pump volutes, impellers, valve covers, filter housings, quick connectors, plumbing unions, and sanitary brackets. For long-term hydrostatic strength in pressurised water systems, design values are derived from ISO 9080 and classified under ISO 12162. The manufacturer should provide MRS data for the specific pipe or fitting design and joining method because hydrostatic strength depends on weld-line position, wall thickness, and moulded-in stress.

Regulatory acceptance is application-specific. The FWA suffix indicates a formulation position for food-contact and drinking-water use; common certification pathways include EU Regulation 10/2011, FDA 21 CFR 177.1500, KTW-BWGL, W270, WRAS, and NSF/ANSI 61. Published data for this exact black 9225 pigment and stabilised configuration under all local certification schemes is limited; therefore positive listing, migration testing, and lot-specific certificates must be confirmed before specification. Because carbon black pigmentation can affect migration behaviour, compliance is not automatically transferred from natural-pigment versions.

Chemical resistance follows the PA12 matrix. The grade resists oils, greases, fuels, and aliphatic hydrocarbons. Concentrated strong acids, oxidising agents, and hot chlorinated water above 60°C require testing to ISO 175 with the actual service fluid. In potable-water systems with residual chlorine, long-term hydrostatic testing should include the expected chlorine concentration, pH, and temperature because oxidative degradation of the polyamide matrix can reduce crack-initiation time at weld lines.

Compared with PA66-GF50, the PA12 matrix provides lower moisture uptake and more stable conditioned modulus in high-humidity service. PA66-GF50 typically reports dry tensile modulus around 15,000–16,000 MPa and HDT/A near 240°C–250°C. LV-50H FWA black 9225 gives up some dry heat resistance, with HDT/A near 160°C, but its water absorption is lower and its sub-zero impact behaviour is generally better because the PA12 glass transition is lower than PA66. The choice between PA66-GF50 and PA12-GF50 therefore depends on whether the part is dominated by dry heat exposure or humid dimensional control.

Against semi-aromatic PPA-GF50 grades, the PPA class offers higher HDT/A, commonly above 280°C, but requires mould temperatures above 120°C and tighter melt-temperature control. LV-50H FWA black 9225 can be moulded on standard water-heated tools at 80°C–100°C, which reduces tooling cost and energy demand in applications that do not require continuous high-temperature structural service. The PA12 grade is not a replacement for PPA in under-hood components that see continuous temperatures near 150°C or above.

Compared with glass-filled PBT or PET, PA12-GF50 generally has lower dry modulus but better low-temperature notched impact and better resistance to hot-water hydrolysis. Glass-filled PBT may provide higher rigidity and better dielectric stability but is more susceptible to hydrolytic degradation in hot water. The choice for water-meter bodies often shifts to PA12 because the aliphatic amide concentration is lower than that of PA6 or PA66 and significantly more hydrophobic than PBT.

Relative to impact-modified PA12 and unfilled PA12, the 50% glass-filled product has lower ductility and higher stiffness. Snap-fit and living-hinge designs should not be assigned to this grade. The notched Charpy impact at 23°C is approximately 15 kJ/m² dry; at sub-zero service temperatures, ISO 179-1/1eA data at the target temperature should be used because fibre-filled polyamides show a ductile-to-brittle transition that is product- and pigment-specific. If published data for the black 9225 pigmentation at the target temperature are unavailable, lot-specific testing is commissioned.