EMS-Grivory Grilamid® LBKN-30H FWA NATURAL PA12-GB is a spherical glass-bead-reinforced polyamide 12 compound with a nominal filler loading of 30 wt%. The grade designation distinguishes it from short-glass-fibre and mineral-filled polyamide 12 products by the geometric form of the reinforcement: glass microspheres rather than cylindrical glass filaments. The “FWA” suffix identifies a formulation positioned for food-contact and potable-water application evaluation, and “NATURAL” indicates an uncoloured base resin that may be processed as supplied or converted to approved coloured variants. Under dry-as-moulded conditions, the published typical density is approximately 1.25 g/cm³ according to ISO 1183-1. As a PA12 matrix, the compound retains the low amide density, low moisture uptake, broad chemical resistance to aliphatic and aromatic hydrocarbons, and low-temperature impact behaviour characteristic of the polymer family. Compared with unfilled PA12, the 30 wt% glass bead phase raises modulus and reduces mould shrinkage. Compared with 30 wt% short-glass-fibre PA12, the same bead loading produces lower tensile modulus and notched impact strength but much lower fibre-orientation-induced warpage and more isotropic shrinkage. The grade is therefore specified for precision mouldings that require dimensional stability in humid or aqueous service rather than maximum load-bearing capacity.

Why Does 30 wt% Glass Bead Reinforcement Alter Melt Flow, Screw Recovery, and Shrinkage Anisotropy?

The spherical reinforcement changes melt rheology by increasing suspension viscosity relative to the unfilled matrix, but without the strong flow-induced orientation that occurs in fibre-reinforced melts. In injection-moulding practice, the result is a smaller flow-to-transverse shrinkage differential and reduced out-of-plane warpage in flat parts. Screw recovery on standard 20:1 to 25:1 L/D general-purpose polyamide screws is typically stable if the non-return valve is maintained with a sliding clearance below 0.05 mm; glass beads can trap in worn check rings and produce shot-weight drift. Melt temperature is commonly set between 220°C and 250°C. Mould wall temperatures between 40°C and 80°C are used to control crystallinity and weld-line strength in multi-gate tools. Back pressure settings from 50 bar to 100 bar and injection velocities from 50 mm/s to 150 mm/s are representative starting points for filled PA12 formulations, but the final parameter set must be established by flow-length-to-thickness trials and by observing gate blush and jetting. Because glass beads have a lower aspect ratio than milled glass fibre, shear heating and melt-temperature overshoot are generally lower at equivalent filler weight fraction. Spherical filler, however, reduces the extensional strength of the melt and may promote jetting through undersized gates. Gate land diameters below 1.0 mm and very high shear rates above 100,000 s⁻¹ can cause filler–matrix separation at the melt front. For wall thicknesses from 2.0 mm to 4.0 mm, tab or fan gates are preferred over pin-point gates.

Pre-drying is required if the granulate has been exposed to ambient humidity. For PA12 compounds, EMS-Grivory technical guidance recommends drying to a residual moisture content below 0.10 wt% before melt processing. Typical drying conditions are 80°C for 4 h to 8 h in a desiccant dryer with a dew point at or below -40°C. If residual moisture exceeds 0.15 wt%, the melt may exhibit silver streaks, nozzle drool, and reduced weld-line strength due to hydrolytic chain scission at processing temperature. Over-drying above 90°C or exceeding 10 h should be avoided because polyamide thermal stabilizers can degrade and shift natural colour or reduce impact resistance. Dried granulate should be processed through closed hopper systems or consumed within a moisture-protected holding period determined by plant humidity.

Dimensional Stability, Moisture Sorption, and Creep Response Depend on Conditioning History

The PA12 matrix in LBKN-30H FWA NATURAL absorbs less water than PA6 or PA66 because the molar concentration of amide groups is lower. Conditioned at 23°C and 50% RH, equilibrium moisture uptake of unreinforced PA12 is commonly around 0.7 wt%; the glass bead phase lowers matrix volume fraction and reduces the dimensional change associated with water sorption. At saturation in water at 23°C, polyamide 12 absorbs approximately 1.4 wt% according to ISO 62; glass bead-filled grades often exhibit slightly lower total uptake. The shift from dry-as-moulded to conditioned state lowers tensile modulus and increases toughness. For this grade, published data for the exact dry-to-conditioned modulus shift is limited; however, the matrix response follows the general polyamide 12 pattern of a 10% to 20% reduction in tensile modulus at 50% RH. Dimensional growth from moisture absorption is nearly isotropic because the spherical filler does not create oriented pathways along which water preferentially diffuses in fibre-filled grades. This supports use in pump impellers, valve bodies, flow-meter housings, and filter heads where clearance changes between dry assembly and water service must be controlled. Glass bead reinforcement also increases apparent creep modulus relative to unfilled PA12 under ISO 899-2 tensile load at elevated temperature, but the improvement is less than that achieved with short-glass-fibre reinforcement. For applications requiring long-term creep resistance at loads above 15 MPa and continuous exposure above 80°C, a short-glass-fibre PA12 or a higher-temperature engineering polymer should be evaluated because the bead–matrix interface and the PA12 crystalline phase control long-term deformation.

The PA12 matrix provides resistance to aliphatic and aromatic hydrocarbons, many automotive fluids, alkaline cleaning solutions, and non-polar process media. Glass bead filler does not compromise the base polymer’s resistance, but any coupling agent or surface sizing must be hydrolytically stable in hot water. In aqueous service at temperatures above 60°C, long-term hydrolysis resistance is more dependent on compound stabilization than on filler geometry. Dissolved chlorine or ozone in water distribution systems may attack polyamide at high local stress; such environments require stress-rupture testing following ISO 22088-2 or equivalent long-term pressure-test protocols. Published data for this specific configuration under cyclic hot-water pressure is limited, so prototype testing under end-use hydraulic and thermal cycling is required before production release.

When Food-Contact or Potable-Water Compliance Constrains Material Selection

The FWA designation is an application-focused formulation designation rather than an unconditional approval. EMS-Grivory technical documentation for food-contact PA12 grades may reference compliance with European Commission Regulation EU 10/2011 and with the U.S. Food and Drug Administration framework under 21 CFR 177.1500 for nylon resins. The current formulation-specific certificate should be obtained before tooling release because compliance depends on food simulant type, contact time, temperature, and whether the grade is used in natural or compounded form. For potable-water components, products may be evaluated under NSF/ANSI/CAN 61, but certification is assembly-specific and cannot be transferred from raw material to finished device without testing. In the European drinking-water sector, national or industry schemes such as KTW-BWGL or DVGW W270 may apply, and equivalence across approval bodies is not automatic. The glass bead filler is encapsulated within the polymer matrix; however, the final moulded surface can expose fractured beads or matrix microcracks, and aggressive cleaning agents at elevated temperature may promote extraction of water-soluble additives. Designers should therefore avoid the use of post-mould amine-based adhesion promoters, solvent-based marking inks, or unapproved anti-scale coatings without repeating the relevant migration tests. The processing window also affects compliance: excessive melt residence time above 250°C or regrind fractions above 25% may shift the additive degradation profile and influence migration behaviour.

Selecting Between Glass-Bead-Filled PA12, Short-Glass-Fibre PA12, and Unfilled PA12

The choice among these three PA12 classes is determined by the balance between stiffness, warpage tolerance, and dimensional stability. Unfilled PA12 is preferred for clips, dynamic seals, and sound-damping parts because of high elongation and low modulus. Short-glass-fibre PA12 is used for structural brackets, fan blades, and pressure-bearing supports where high stiffness justifies additional warpage correction. Glass-bead PA12 is specified for round valve bodies, pump housings, and flow-meter chambers where bore roundness and seal-groove parallelism are more important than ultimate tensile strength. The spherical filler also creates a less abrasive surface in sliding contact with elastomer seals than milled glass fibre, although PTFE-filled PA12 may be required for low-speed high-load dry sliding. Table 1 gives representative industrial ranges for dry-as-moulded properties. The table is not a specification and should not replace lot-specific certificate values.

Tool design for EMS-Grivory Grilamid® LBKN-30H FWA NATURAL should account for lower and more isotropic mould shrinkage than unfilled PA12. Shrinkage values in the range of 0.7% to 1.0% are typical for 30 wt% glass-bead-reinforced PA12 in the flow direction according to ISO 294-4; transverse values are often within 0.1 percentage point of the flow value, which is a defining difference from short-glass-fibre grades. The low aspect ratio of glass beads also produces a smoother surface finish and less tool wear than fibre-filled compounds. However, weld lines remain the limiting mechanical feature. In multi-gate or multi-impression tools, weld-line strength is governed by melt temperature, mould wall temperature, and the ability to maintain a moving melt front; end-of-fill cavity pressure above 50 MPa is often required to produce acceptable weld-line strength. Mould surfaces should be vented at the end of flow with vent depths from 0.01 mm to 0.03 mm to prevent burning and short shots. The natural colour of the grade provides a neutral base for colour compounding; colourants and masterbatch carriers should be chosen for thermal stability above 250°C and for compatibility with the PA12 matrix to avoid loss of bead–matrix adhesion.

Application examples for EMS-Grivory Grilamid® LBKN-30H FWA NATURAL appear in precision-moulded fluid-handling components, pump housings, valve bodies, filter fittings, flow-meter chambers, and food-processing machine parts. In these parts, the grade is selected because glass bead reinforcement reduces the dimensional asymmetry found in fibre-filled thermoplastics and because the PA12 matrix resists hydrolysis and stress cracking in humid service. Components with wall thickness from 2.0 mm to 4.0 mm and close-tolerance circular bores benefit from the lower and more predictable post-mould shrinkage. Continuous exposure to hot water above 80°C may accelerate oxidative degradation, reduce weld-line strength, and alter compliance status; short-term peaks above 100°C should be validated for the specific part geometry and applied stress. For load-bearing structural parts or applications requiring high stiffness at elevated temperature, a short-glass-fibre PA12 or a higher-temperature engineering polymer should be evaluated.