Evonik VESTAMID® L-GF30 BK 9.7506 is a black-pigmented polyamide 12 injection-molding compound containing 30% glass fiber by mass. Its ISO 1043 generic designation is PA12-GF30; the suffix BK 9.7506 identifies the black color package. The polyamide 12 matrix contributes low moisture uptake and resistance to automotive fluids, while the glass-fiber network increases modulus, creep resistance, and heat deflection. Representative density is 1.24 g/cm³ under ISO 1183-1:2019. This density is below short-glass PA66 grades at the same filler loading and supports light-weighting in fluid-handling brackets, sensor housings, and fasteners. The product is formulated for melt processing by injection molding; published data for this specific configuration is limited for extrusion or blow molding, and those processes may require separate homologation.

What Mechanical Property Shift Is Produced by the 30% Glass Reinforcement?

Dry-as-molded tensile modulus is approximately 6000 MPa under ISO 527-1/-2. Tensile stress at break is approximately 125 MPa, and tensile strain at break is approximately 4%. These values indicate that the material behaves as a fiber-dominated composite: the glass network sharply reduces the ductility of the PA12 matrix but raises stiffness. In notched Charpy testing to ISO 179-1/1eA, the impact strength is approximately 11 kJ/m² at 23°C and 9 kJ/m² at -30°C. The low-temperature value is close to the transition from ductile to brittle failure, so snap-fit designs intended for assembly below -20°C require prototype validation. Heat deflection temperatures are approximately 160°C at 1.8 MPa and 170°C at 0.45 MPa by ISO 75-1/-2. Vicat softening temperature B50 is approximately 165°C by ISO 306. These values confirm that the grade is suitable for short-term thermal exposure in engine peripheries but is not a high-temperature specialty polymer such as PPA or PEEK.

Representative values are derived from dry-as-molded specimens and must not be construed as specification limits.

Within the VESTAMID L glass-fiber series, the 30% grade is located between products with lower glass content such as VESTAMID L-GF15 or VESTAMID L-GF25 and products with higher content such as VESTAMID L-GF50. The lower-glass grades offer longer flow length and lower melt viscosity but at lower tensile modulus; the higher-glass grades increase stiffness and surface hardness but raise screw wear and reduce weld-line integrity. The BK 9.7506 designation indicates black pigmentation; black coloration alone does not guarantee long-term UV stabilization. Outdoor components requiring accelerated weathering performance should be tested according to ISO 4892-2 or equivalent, and the relevant stabilized variant should be requested where applicable.

Processing Boundaries, Moisture Control, and Anisotropic Mold Shrinkage

Drying is mandatory before molding. In dry-air drying equipment, 80°C for 4–8 h lowers residual moisture to below 0.1%. Although PA12 is less hygroscopic than PA6 or PA66, moisture on the granule surface creates splay and may reduce weld-line impact. Melt temperatures from 240°C to 280°C are used, with the barrel profile from feed to nozzle steadily increasing. The melt must not exceed 280°C for continuous periods above approximately 10 min, because thermal degradation of the fiber sizing and polyamide matrix leads to yellowing, volatile generation, and loss of mechanical properties. Mold temperature is set between 40°C and 80°C; the upper range is specified for dimensional control and reduced glass-fiber read-through on appearance surfaces. Injection speed and screw speed are kept moderate to avoid shear heating beyond 300°C. Because the glass-fiber network is abrasive, bimetallic barrels, hardened check rings, and hard-coated screw flights are recommended for campaigns above approximately 20,000 cycles; this recommendation is based on equipment wear behavior in glass-filled polyamide processing, not on a specific batch sensitivity.

Mold shrinkage is anisotropic. Values determined by ISO 294-4 are approximately 0.25% parallel to flow and 0.90% transverse to flow. Isotropic shrinkage models underpredict transverse movement; mold design for this grade must account for flow direction, gate location, and fiber orientation. Prototype tools should include shrinkage coupons in both orientations to confirm molded dimensions before full-scale mold cutting.

Regrind use is process-specific. Dried sprues and runners may be re-introduced up to 20% by mass without major loss in typical tensile properties, provided the regrind is free from contamination and has not experienced multiple heat histories. Repeated processing causes fiber-length degradation; after three regrind cycles, notched Charpy impact may decline by more than 15%. Published data for this exact grade is limited, so the maximum regrind fraction must be fixed by internal trials according to ISO 179-1/1eA and ISO 527-1/-2.

When Moisture Uptake and Chemical Stress Cracking Control the Material Choice

In wet or humid environments, the selection logic shifts away from short-glass PA66. A 30% glass-filled PA66 can absorb on the order of 6% water at saturation under ISO 62, while PA12 GF30 remains near 1.0%. The PA12 grade therefore retains more modulus and dimensional stability after exposure to condensation, steam cleaning, or wet engine compartments. The trade-off is tensile strength: short-glass PA66 at the same filler loading often reports tensile stress at break above 170 MPa, whereas PA12 GF30 is in the 105–125 MPa range. PA12 GF30 is selected when stress-cracking resistance to road salt, hydrocarbon condensate, or plasticizing fluids is the dominant failure mode. Density also favors PA12 GF30: approximately 1.24 g/cm³ compared with 1.35–1.38 g/cm³ for short-glass PA66, a mass reduction of roughly 8–10% at equal part volume. For maximum short-term tensile load in a dry environment, PA66 GF30 may be the stronger selection, provided the operating environment does not impose repeated water exposure.

Chemical resistance testing to ISO 175:2010 is used to evaluate retention of tensile properties after immersion. The PA12 matrix withstands aliphatic and aromatic hydrocarbons, diesel, oils, and many hydraulic fluids at ambient and elevated temperatures. Strong acids, polar solvents such as methanol, and oxidizing agents attack the polyamide or the glass-fiber surface. Glass fibers are particularly sensitive to hydrofluoric acid and strongly alkaline solutions, which can etch exposed fiber ends and create a rough molded surface. For components exposed to high-pH cleaners, steam sterilants, or aggressive de-icing fluids, compatibility must be verified on molded test bars of the actual filled grade; unfilled PA12 chemical-resistance data are not sufficient.

The glass-fiber network also reduces thermal expansion. Linear coefficient of thermal expansion parallel to flow may fall in the range of 30–50 × 10⁻⁶ K⁻¹; transverse values are higher and closer to the PA12 matrix. In inserts or metal-overmolded parts, the differential expansion relative to steel must be managed through flexible attachment features. Under thermal cycling from -40°C to 120°C, the filled grade maintains dimensional stability better than unfilled PA12, but the low-temperature notched Charpy value of 9 kJ/m² indicates that snap-fit or clip features assembled below -30°C should be evaluated for brittle failure. Published fatigue data for this exact black-pigmented grade under reversed bending are limited; design fatigue curves should be generated on molded specimens with the intended fiber orientation and weld-line position.

In production-scale injection molding on 80-ton to 120-ton hydraulic machines, VESTAMID® L-GF30 BK 9.7506 is processed for cable clips, sensor brackets, and fluid-line retainers. The fountain-flow orientation creates a fiber-rich skin and a more matrix-rich core. This structure increases flow-direction modulus but produces weld lines with lower notched impact than gate-proximal material; weld-line impact can be more than 20–30% lower than the bulk value, so gate placement must move weld lines out of high-stress areas. A production bottleneck observed with this class of glass-filled PA12 is gate-stringing in hot-runner systems when gate diameters are below 1.5 mm. The high shear in small gates reduces fiber length and lowers impact strength; gates should be sized to the nominal wall thickness and rounded to prevent filler jamming. Holding pressure in the range of 400–600 bar is used for wall sections of 2–4 mm, with adjustment based on sink-mark appearance and part weight consistency.