The material designated EMS-Grivory Grilamid LV-65H SST black 9288 is classified as a polyamide 12 moulding compound reinforced at 65% by weight with glass fibre. In the conditioned state the compound has reached moisture equilibrium under ISO 291 class 2 atmosphere at 23°C and 50% relative humidity, or has been accelerated-conditioned according to ISO 1110. The base resin is PA12, in which the lower amide-group density relative to PA6 and PA66 limits equilibrium moisture uptake and provides a flatter property profile after humidity exposure. Typical published density is 1.67 g/cm³ determined by ISO 1183-1; the melting endotherm peak is commonly reported at 176°C by differential scanning calorimetry according to ISO 11357-1/-3. The grade incorporates a black pigmentation package and a heat-stabilisation or surface-treatment suffix, and the full suffix nomenclature should be checked against the manufacturer’s batch-specific data sheet because suffix conventions may vary by product family.

At 65% glass-fibre loading, the compound is specified for structural components where high stiffness and reduced moisture-induced dimensional change are required without moving to a semi-aromatic polyamide. The glass reinforcement shifts the tensile modulus from the unfilled PA12 range of approximately 1.4 GPa to the 18–19 GPa dry range, depending on fibre orientation in the test plaque. Fibre concentration at gate restrictions, abrasive wear on screw elements, and anisotropic shrinkage are the primary process constraints. For incoming quality control, ash content may be verified by thermogravimetric methods aligned to ISO 1172, while moisture content is checked by Karl Fischer titration or loss-on-drying at 120°C until constant mass. The conditioned water absorption at 23°C and 50% relative humidity is generally reported below 0.5% by total compound mass, which is lower than glass-filled PA66 materials at the same filler range.

The compound is typically produced on twin-screw extruders with L/D ratios of 44:1 to 48:1. Glass fibre is fed downstream into a peroxide-free polymer melt to limit fibre breakage, and vacuum devolatilisation at the vent port removes residual moisture and volatiles. Because glass fibre content is high, side feeders and vent inserts are subject to abrasive wear; production lots are screened by melt viscosity, ash content, and colourimetric data. Published process conditions for this specific grade are proprietary to EMS-Grivory, but the described configuration is standard for long-glass PA compounds.

What Standardised Test Procedures Apply to the Dry and Conditioned Values?

Dry-as-moulded values are obtained immediately after injection moulding of ISO multipurpose test specimens and after sealing in moisture-barrier packaging until testing. Conditioned values are obtained after exposure to ISO 291 class 2 atmosphere or after accelerated conditioning according to ISO 1110. The following table compiles representative manufacturer-typical values for this grade and should not be interpreted as a batch-release specification. Lot-specific certificates of analysis may show variation around the listed values because of fibre orientation, mould temperature, and conditioning history.

Long-Glass-Fibre Reinforcement, Fibre Attrition, and Weld-Line Strength

Long-fibre feedstocks retain fibre length through plastication when low-shear screw designs and generous runner diameters are used, but fibre attrition still occurs along the melt path. The practical result is that mechanical data from end-gated ISO tensile bars reflect a high degree of longitudinal orientation; transverse properties measured on plaques may be 20–40% lower for modulus and strength. Weld-line retention is another limitation: in glass-filled polyamides, the weld-line tensile strength may fall to less than 50% of the value obtained from a weld-line-free specimen, because glass fibres do not cross the melt front and the load is carried mainly by the polymer matrix. For Grilamid LV-65H SST black 9288, published data for weld-line strength in specific part geometries is limited; designers should determine weld-line properties on prototype mouldings using ISO 527-2 specimens cut across the weld line. Gate positioning, sequential valve gating, or overflow wells can move the weld line out of high-stress regions but do not eliminate the fundamental strength reduction.

In terms of fibre orientation effects, mould-filling simulations for long-glass compounds should use anisotropic material cards calibrated on plaque specimens. Fibre orientation tensors extracted from micro-computed tomography or polished sections are preferred over default database values. The high filler fraction produces melt viscosity that is strongly shear thinning but also increases melt-temperature sensitivity; processing above 280°C or residence times beyond 6 minutes may initiate thermal degradation of the PA12 matrix, visible as yellowing, viscosity reduction, or surface delamination. Published kinetic data specific to this grade are limited, but the general PA12 degradation onset at high temperature is well documented. Shot weights should be selected at 50–80% of barrel capacity to limit residence time, and hold pressures should be profiled to avoid overpacking at gates, which otherwise raises fibre orientation gradients and warpage.

When the Grade Replaces Semi-Aromatic PPA or Glass-Filled PA66 in Structural Housings

Grilamid LV-65H SST black 9288 provides lower equilibrium moisture uptake than glass-filled PA66 at comparable filler loadings. A PA66-GF60 grade may absorb roughly 1.0–1.5% water at 23°C and 50% relative humidity by total compound mass, while the PA12-GF65 class remains below 0.5%. The practical consequence is less dimensional change between dry winter and humid summer service, and a flatter stiffness retention after conditioning. The trade-off is thermal: the melting point of PA12 is approximately 176°C, and the deflection temperature under load at 1.8 MPa is typically near 170°C, whereas glass-filled PA66 may report HDT values above 240°C and semi-aromatic PPA grades can exceed 280°C. Continuous-use temperatures for PA12-GF65 are therefore restricted to environments below roughly 100–120°C under mechanical load; published data for this specific configuration is limited, and OEM-specific heat-aging protocols should be applied before substitution.

Chemical compatibility differs from PA66. PA12 generally resists aliphatic hydrocarbons, diesel fuel, lubricating oils, greases, salt solutions, and many hydraulic fluids, and it is less sensitive to hydrolysis than PA66 in humid or wet environments. The compound is not recommended for continuous exposure to hot strong acids, strong oxidizing agents, or alcohols at elevated temperature, and resistance to hot glycol/water mixtures should be verified for the specific temperature and glycol concentration. When replacing PA66 in a fuel or pneumatic quick connector, the lower moisture uptake of PA12 can reduce the post-moulding dimensional drift, but the lower heat-deflection temperature means the part must be checked for peak under-hood conditions. Electrical tracking resistance, if required, should be requested as IEC 60112 proof-tracking index; typical glass-filled PA12 grades may report CTI values in the 600 V class, but the specific lot value should be confirmed.

Pre-drying is mandatory. The compound should be dried in a desiccant dryer at 80°C for 4–6 hours to a residual moisture content below 0.1% by weight. If moulding is performed in an environment above 60% relative humidity, exposure of dried granulate to ambient air should be limited to 30 minutes before re-drying is required. Melt temperatures from 250°C to 280°C are typical for PA12-GF65, with a mould surface temperature of 80–100°C to promote crystallisation and to reduce surface defects. Injection speed should be moderate to high to minimise premature skin formation, but excessive speed can increase shear heating and fibre abrasion. Screw geometry should use a low-compression ratio, wear-resistant nitrided or bimetallic barrel, and a free-flow ring check valve; reciprocating-screw units with L/D ratios of 20:1 or greater are standard for glass-filled polyamides. Production-scale trials on glass-filled polyamides generally use projected-area clamp force of 0.5–0.8 tons/cm² and cavity pressures of 40–80 MPa, though published data specific to this grade are limited. Because the compound is highly abrasive, maintenance intervals for screws, barrels, and mould gates are shorter than for unfilled PA12.

When the component is used in electrical or electronic housings, volume resistivity and surface resistivity should be measured according to IEC 62631-3-1 and IEC 62631-3-2. Polyamide 12 is inherently hygroscopic but less conductive than PA66 at elevated humidity; the glass fibre does not significantly lower the tracking resistance of PA12, and many filled grades fall into the 600 V CTI category under IEC 60112. The flame rating is generally UL 94 HB at wall thicknesses commonly used for structural parts, but halogen-free flame-retarded variants are not to be assumed from this grade unless explicitly supplied. These characteristics differ from unfilled PA12 mainly because the glass concentration reduces volume resistivity only marginally while increasing dielectric constant and dissipation factor; specific values for the 65% glass configuration should be taken from the current material database.

The conditioned state should not be confused with improperly dried granulate. Conditioning of finished parts is performed after moulding and is intended to produce a repeatable moisture content in the polymer matrix. Processing with undried granulate produces surface splay and hydrolysis-induced molecular weight reduction; conditioning after moulding produces a controlled increase in toughness and a controlled decrease in stiffness. For PA12, equilibrium moisture uptake at 23°C and 50% relative humidity is reached after several weeks in thin sections, but ISO 1110 accelerated conditioning can reduce the time to days or hours depending on part thickness. The property shifts from dry to conditioned shown in the table above are reversible at room temperature only if the part is re-dried, in which case the dry values return approximately.

Regrind use in production should be limited to 20% by weight with virgin material for critical mechanical components because regrinding reduces fibre length and can increase ash-content variance. Batch-to-batch variation in glass length distribution should be monitored by melt viscosity or tensile modulus on a control plaque after every silo change. Hydraulic injection units with closed-loop transfer control are preferred because the compound exhibits shear-rate-dependent viscosity; open-loop shooting can produce short shots or flash at the same temperature if speed is not controlled.

Relative to Grilamid LV-50H or a 50% glass-filled PA12, this 65% grade increases tensile modulus and creep resistance but reduces notched impact and processability. The higher glass content raises melt viscosity and requires larger gates and vents; vent depth should be kept at 0.01–0.02 mm to avoid flash while allowing gas evacuation from the melt. Tooling wear is also more severe at 65% loading than at 30% or 50% glass. The exact difference in Charpy impact between the 50% and 65% glass variants should be taken from the manufacturer’s comparative data because impact response depends on fibre sizing and matrix modification.

Applications for the conditioned grade include structural brackets, coupling bodies, actuator housings, pneumatic valve bodies, pump wear rings, gear wheels, and automotive quick connectors where stiffness, chemical resistance, and low moisture uptake are required. For fuel-contact connectors, validation may follow SAE J2044 or fluid compatibility programs based on ISO 1817 immersion in ASTM Reference Fuel C or diesel at defined temperatures. In gear applications, tooth-load capacity should be evaluated by VDI 2736 or OEM-specific gear test methods, because the high glass-fibre content increases stiffness but reduces elongation at tooth root compared with unfilled PA12. In threaded inserts and snap-fit arms, stress concentrations at sharp corners should be radiused to at least 0.5 mm to avoid fibre-matrix separation; the lower strain at break of the dry state makes installation damage on snap-fit features more likely than with conditioned parts. For outdoor electrical housings, tracking resistance and weathering should be tested to IEC 60112 and ISO 4892-2 or ISO 4892-3 because black pigmented PA12 can exhibit surface chalking after long UV exposure unless stabilised. Compliance with RoHS 2011/65/EU and REACH EC 1907/2006 should be verified against the supplier declaration for the specific lot; generic PA12-GF65 classification does not automatically confer food-contact or drinking-water approvals.