EMS-Grivory Grilamid® LV-65H FWA nat is an injection-moulding grade of polyamide 12 reinforced with 65 wt% glass fibre and classified as PA12-GF65 according to ISO 1874-1. The product is supplied in natural colour and carries the FWA suffix for formulations intended for food-contact and potable-water service, subject to finished-article approval. In EMS-Grivory nomenclature, the L prefix identifies the PA12 backbone, the V modifier denotes glass-fibre reinforcement, and the 65H segment indicates 65 wt% fibre loading with heat stabilisation. Compared with PA66-GF60 and semi-aromatic PPA-GF65 compounds, the PA12 base provides reduced saturation moisture uptake and a more stable mechanical profile under humidity cycling. The high glass content produces elevated tensile and flexural modulus, making the material a technical option for metal replacement in valves, pump bodies, water-meter chambers, and load-bearing kitchen-appliance structures. The following sections provide specification ranges, processing boundaries, comparative differences, and application constraints without promotional claim.

Representative dry-as-moulded mechanical data measured on standard test specimens include a density of 1.68 g/cm³ under ISO 1183, tensile modulus of approximately 21,000 MPa under ISO 527-1/-2, and tensile stress at break of approximately 160 MPa. Elongation at break is typically below 3 %, consistent with a highly filled PA12. Charpy notched impact strength at 23 °C is approximately 15 kJ/m² when tested to ISO 179/1eA; the unnotched value is approximately 65 kJ/m². Heat deflection temperature under 1.8 MPa load is approximately 175 °C to 180 °C per ISO 75-1/-2. These values are not lot-specific guarantees; the manufacturer datasheet should be consulted for exact quality release limits.

How does the 65 wt% glass level alter moisture uptake and dimensional stability compared with PA12-GF50?

The transition from 50 wt% to 65 wt% glass-fibre reinforcement reduces mould shrinkage and lowers the coefficient of linear thermal expansion in the flow direction, while raising melt viscosity and mould wear burden. Saturation moisture uptake for PA12-GF65 is approximately 1.0 wt% under ISO 62; this is significantly lower than the 4.5–6.0 wt% saturation uptake typical of PA66-GF60. Conditioned tensile modulus for LV-65H FWA nat is approximately 17,000 MPa, whereas a conditioned PA12-GF50 may fall to approximately 12,000–13,000 MPa. The lower amide density in PA12 contributes to slower moisture diffusion and reduced property drop in wet environments. Longitudinal CLTE is approximately 0.2×10⁻⁴ K⁻¹, while transverse CLTE is higher due to fibre orientation; design tolerances must account for anisotropic expansion in components such as water-meter register plates. Peak melting temperature for PA12-GF65 is approximately 175–185 °C when measured by differential scanning calorimetry to ISO 11357-3. The processing window remains above this range because the high fibre content raises viscosity, but it is still lower than the 280–300 °C melt-processing range of PPS-GF65 and the 320–340 °C range of semi-aromatic PPA-GF65.

In potable-water and food-contact equipment, LV-65H FWA nat is injection moulded into valve bodies, impeller hubs, pump housings, manifold fittings, and structural supports where sustained hydrostatic pressure and dimensional precision are required. Production-scale experience shows that the high fibre content increases gate wear, necessitates hardened mould inserts, and can generate fibre orientation gradients in thin ribs. Parts with wall thickness below 1.5 mm can exhibit short shots if the melt front cools prematurely; moulders often raise tool temperature to 110 °C and use sequential valve gates to maintain fill. Batch-to-batch flow variation is managed by melt flow rate measurement under ISO 1133-1, typically at 275 °C with 5 kg load for PA12-GF grades. In water-meter housing production, the lower saturation uptake of PA12-GF65 reduces the risk of clearance variation between register components after prolonged immersion. Moulders using this grade have observed that pressure-tight housings can be produced with wall sections of 2–3 mm when gate locations avoid weld lines across the sealing face. However, mould shrinkage is anisotropic: longitudinal shrinkage may be as low as 0.1 %, while transverse shrinkage may reach 0.4 % depending on fibre orientation near the gate. Tooling should be designed with adjustable inserts or initial steel-safe dimensions to correct for anisotropic contraction.

Pre-drying and melt-processing boundaries govern pressure-tight part production.

The compound must be dried to a residual moisture content below 0.10 wt% before processing. Desiccant drying at 80 °C for 4–8 h with supply air dew point below -30 °C is standard equipment practise. Residual moisture above 0.15 wt% can hydrolyse the PA12 backbone during plasticisation and reduce melt viscosity, leading to splay, surface roughness, and lower weld strength. Barrel temperature profiles are normally set from 240 °C in the feed zone to 270–280 °C at the nozzle; melt temperature above 290 °C shortens residence-time tolerance to under 5 min. Mould temperature should be held between 80 °C and 110 °C. Below 80 °C, slow crystallisation and premature skin formation hinder post-mould dimensional stability. Injection moulding machines with L/D ratios of 20:1 to 24:1, wear-resistant bimetallic barrels, and hardened check rings are required. The glass-fibre reinforcement increases screw and barrel wear compared with unfilled PA12; screw flights should be inspected at intervals not exceeding 40,000 cycles in high-volume water-component production.

The melt-temperature processing window is narrower than for unfilled PA12. At 250 °C, fibre wetting and surface appearance may be acceptable, but incomplete homogenisation of the 65 wt% fibre bundles can produce islands of glass-rich material at the flow front. At 295 °C, residence-time tolerance falls below 5 min, and prolonged exposure produces yellowing and acrid decomposition. A stable barrel profile with control tolerance of ±5 °C is therefore required around the set point. On multi-cavity tools with unbalanced runners, shear heating in the gates can raise local melt temperature above the set point, causing variable shrinkage and warpage. During plastication, the high fibre content creates pronounced shear-thinning behaviour. Mould filling simulations using material-specific viscosity data are required because generic PA12-GF parameters underestimate pressure loss in thin sections. Short-shot studies on hydraulic machines with injection pressure up to 140 MPa are used to establish the venting and gate location plan. Hot-runner systems require free-flow channels with minimum diameter of 6 mm and no reverse-taper dead spots; otherwise glass bundles can stagnate and degrade into black specks. Amine-containing processing aids are not recommended because they may accelerate PA12 hydrolysis at elevated processing temperatures.

Comparative positioning versus PA66-GF60 and semi-aromatic PPA-GF65 in aqueous service

PA66-GF60 typically exhibits higher dry tensile strength in the range of 220–240 MPa and a similar HDT/A near 250 °C, but its saturation water uptake under ISO 62 is approximately 5.0–6.0 wt%. The PA12-GF65 grade has lower amide concentration, yielding lower moisture absorption, better retention of modulus in humid environments, and reduced swelling in precision clearances. Semi-aromatic PPA-GF65 can exceed 280 °C HDT/A and offers better retention at elevated temperatures, but typically requires higher mould temperatures of 120–150 °C and has a narrower processing window. PPA-GF65 may also display lower notched impact than PA12-GF65 in cold-water applications. The choice between PA12-GF65 and PPA-GF65 is therefore governed by the upper service temperature and chemical environment rather than by fibre content alone. Compared with PPS-GF65, LV-65H FWA nat has lower density and lower continuous-use temperature but a lower melt-processing range. PPS-GF65 density is approximately 1.95 g/cm³; its HDT/A can exceed 260 °C, but its notched impact is often below 10 kJ/m². PA12-GF65 offers higher weld-line elongation and is less sensitive to hot-runner residence time than PPS-GF65. Compared with PEEK-GF30, the PA12 grade has lower maximum service temperature and lower chemical resistance, but a lower melting range and less demanding mould-temperature requirement.

Within the Grilamid L portfolio, the 65H grade increases tensile modulus by approximately 30 % over the 50 wt% glass-reinforced grade and by approximately 60 % over the 40 wt% grade, while notched impact declines. The 65H grade should not be substituted for LV-50H FWA nat in snap-fit or high-vibration parts unless impact analysis confirms adequate safety factors. Conversely, replacing LV-50H with LV-65H in housings can reduce wall thickness for stiffness-limited designs, but the exact reduction must be calculated using the measured modulus and safety factor of the finished component. Because the base polymer is PA12, the material has lower water absorption than PA6 and PA66 equivalents; however, the high fibre fraction reduces the toughness reserve that would normally be available in unfilled PA12.

If weld lines cross hydrostatic sealing faces, the high fibre fraction reduces damage tolerance.

Weld-line tensile strength in glass-fibre-reinforced polyamides is commonly 30–40 % lower than the base tensile strength because glass fibres do not bridge the knit line effectively. In LV-65H FWA nat, this reduction means a weld line in a pressure boundary may sustain less than 100 MPa even when the nominal tensile stress at break is 160 MPa. Components such as pump bodies with opposing gates should be assessed by burst testing to the applicable product standard for the finished fitting or valve. Fillet radii less than 0.5 mm at high glass content can act as crack-initiation sites, particularly in bosses and mounting lugs subjected to assembly torque. Hydrostatic pressure testing should be carried out on conditioned parts because moisture uptake reduces modulus and may redistribute stress at the weld line. The natural colour grade is not inherently UV-stabilised for outdoor exposure; applications subject to sunlight should be black-pigmented or provided with an external UV barrier. Because of the high fibre content, painting and adhesive bonding require surface preparation such as plasma or corona treatment to avoid interfacial failure. Direct contact with strong mineral acids, phenol, or oxidising chemicals should be avoided.

The grade may be coloured by dry blend at the press, but colour masterbatch addition changes shrinkage and mechanical properties; approval for food-contact and potable-water applications must be revalidated after any colourant change. Published data for this specific configuration in aggressive chlorinated water at elevated temperature is limited, so long-term hydrostatic testing should be performed under the target service conditions before production release. The compound should be stored in sealed, moisture-proof packaging and dried before each processing campaign if the packaging has been opened for more than 24 h at ambient relative humidity above 60 %. Regrind of highly glass-filled PA12 is possible only at controlled ratios, typically below 30 wt%, because repeated heat history shortens glass fibre length and reduces impact strength.