BASF ecovio® IA1652 is a mineral-filled injection molding grade identified by the supplier as a compostable PLA-based compound. The formulation is intended for rigid molded articles in which stiffness, dimensional reproducibility, and industrial compostability under EN 13432 are simultaneous requirements. The mineral phase functions as a reinforcing filler, raising elastic modulus and reducing post-mold shrinkage anisotropy relative to unfilled PLA. The product is supplied in pellet form and is applied principally in rigid packaging components, writing instruments, horticultural clips, coffee capsules, cosmetic packaging, and other thick- or thin-wall injection molded goods where compostability is needed at end of life.

Compounding of the mineral filler into the PLA matrix is typically performed on twin-screw extruders with L/D ratios above 32:1. Production experience shows that poor side-feeder calibration can generate filler agglomerates that appear later as surface pitting in molded parts. Melt-pressure fluctuation across the screen pack exceeding 1 MPa during compounding often correlates with dispersion instability or filler buildup on the screen. The compound is shear-thinning in the injection molding shear-rate range, and molders should not treat the ISO melt-flow value as a substitute for injection rheology.

How does the mineral phase alter stiffness, impact response, and heat deflection?

The filler raises stiffness and lowers ductility when compared with unfilled PLA injection grades. Tensile modulus is evaluated according to ISO 527-2, and published datasheet ranges for this mineral-filled class typically fall between 3000 MPa and 4000 MPa. Tensile stress at break under the same method is generally in the range of 30 MPa to 45 MPa, with nominal tensile strain at break below 5%. Flexural modulus measured under ISO 178 usually exceeds the tensile modulus by a small margin because of the bending stress gradient. Notched Charpy impact strength under ISO 179-1/1eA at 23 °C is commonly below 5 kJ/m², indicating that the material is not suitable for impact-dominated snap-fit designs without careful gate location and wall-thickness analysis.

Heat deflection temperature under ISO 75-2/B at 0.45 MPa is a more meaningful thermal index for rigid packaging than Vicat softening temperature for this compound. Published datasheet ranges for heat deflection temperature are typically between 70 °C and 90 °C. Vicat A softening temperature under ISO 306 is often reported near 80 °C to 100 °C. These values are not load-bearing service temperatures; they are laboratory ranking metrics. For coffee capsule lids or bowls that contact hot food, the molder must verify dimensional stability under the actual load, contact time, and lip geometry.

Density is affected by the mineral filler and is measured under ISO 1183-1. Representative values for this grade class are in the range of 1.42 g/cm³ to 1.48 g/cm³. The higher density compared with unfilled PLA is a direct result of the mineral phase and must be included in per-part weight, packaging, and transportation calculations. Melt volume rate under ISO 1133-1 at 190 °C and 2.16 kg is typically in the range of 9 cm³/10 min to 15 cm³/10 min. This range supports injection molding flow lengths but does not describe the low-moisture viscosity response of the melt.

Moisture control, rather than barrel temperature, is the primary processing boundary for this compound. Pellets subjected to humid storage or open silo transfers absorb surface moisture, and PLA ester linkages undergo autocatalytic hydrolysis at melt temperature. A desiccant dryer is required when ambient relative humidity exceeds 60%. Pre-drying at 80 °C for 4 h to a residual moisture level below 0.025% by ISO 15512 is the standard starting condition. Hopper dryers without desiccant capability are not acceptable during high-humidity campaigns because the dew point cannot be held low enough. Moisture levels above 0.05% can produce visible splay, reduced melt viscosity, and loss of surface definition, particularly in multi-cavity tools with long melt paths.

Injection Molding Drying, Screw Configuration, and Thermal Boundaries

Barrel temperature settings are typically profiled from feed to nozzle as 170–180 °C, 190–200 °C, 200–210 °C, and 200–210 °C. Melt temperature should be maintained between 190 °C and 210 °C. Short excursions to 220 °C may be acceptable only when the total residence time at that temperature is below 90 seconds. Sustained operation above 220 °C accelerates thermal chain scission and produces resin yellowing, reduced mechanical properties, and higher monomer outgassing. Screw recovery should be set so that total shot residence time at melt temperature remains below 8 minutes. During interruptions, the barrel should be purged with a PLA-based purging compound; polyolefin purge materials are not appropriate because they create contamination layers that are difficult to remove from hot runners and valve gates.

Mold temperature is a compromise between cycle time and part performance. The compound can be molded with mold temperatures between 20 °C and 80 °C. For thin-wall articles below 1.2 mm, mold temperatures above 40 °C improve cavity filling and surface replication but can extend cycle time. For thick sections above 3 mm, lower mold temperatures reduce sink-mark development but may increase molded-in stress and warp. Multi-cavity tools with runner diameters between 2 mm and 3 mm require balanced melt delivery because the mineral-filled compound has a narrower processing window than unfilled PLA. Vent depth should be held between 0.01 mm and 0.02 mm to permit gas evacuation without flash. Clamp force estimates of 3–6 kN/cm² of projected area are used as starting points for rigid packaging tools, but this is a general injection molding estimate and not a supplier-rated limit.

The mineral filler produces mild abrasive wear on screws, barrels, check rings, and hot-runner tips. Screws with hardened flights and bimetallic barrels are specified when sustained annual production volumes exceed roughly 50 tonnes per line. Otherwise, wear is often first observed as check-ring leakage that increases fill variability from shot to shot. Hot-runner thermal uniformity is more important with this compound than with unfilled PLA because partially cooled mineral-filled material can produce gate-stringing or cold plug formation in sub-runners.

Shrinkage of the mineral-filled grade is lower and less anisotropic than unfilled PLA. Post-mold shrinkage is not zero, and geometry with abrupt wall-thickness transitions can still develop sink marks if packing pressure is insufficient. Packing pressure should be applied through the gate freeze point; published data for this specific configuration is limited, but standard practice is to maintain packing pressure until gate freeze by monitoring cavity pressure rather than by relying on a fixed timer.

When lower mold temperatures are required for thin-wall rigid parts

Thin-wall applications such as capsule bodies, lids, writing instrument barrels, and cosmetic sleeves often run at mold temperatures between 20 °C and 40 °C to shorten cycle time. Under these conditions, the mineral-filled compound develops lower heat resistance than the datasheet value because crystallinity remains limited. The lower mold temperature may also raise flow-front hesitation behind ribs and bosses, increasing visible knit lines. Weld-line strength under ISO 527-2 can be lower than the unfilled PLA reference, especially when two flow fronts meet after passing around a core pin. If weld lines are load-bearing, the gate should be relocated or the wall section adjusted rather than relying solely on mold-temperature increase.

Thin-wall processing requires higher injection velocities to prevent premature gate freeze. Injection velocity should be profiled so that the melt front does not drop below the hesitation threshold in ribs or hinges. For parts with wall thicknesses below 1.0 mm, cavity-fill analysis should include the effect of filler orientation on melt viscosity. The mineral phase orients during shear, reducing effective viscosity in the flow direction but also reducing transverse mechanical strength. This anisotropic behavior is measurable under tensile testing of specimens cut in and across flow, but published data for this specific configuration is limited.

When replacing unfilled PLA in an existing tool, the mineral-filled grade may require lower injection pressure because of its higher density and different compressibility, but the filled material may freeze faster at the same mold temperature. Gate size should be revalidated. Small gates optimized for unfilled PLA can restrict flow and produce high shear heating, causing local degradation in the gate region. Gate diameters for multi-cavity rigid packaging are usually kept above 0.8 mm for thin-wall parts; smaller gates are possible only with validated short fill times and hot-runner thermal control.

For applications involving hot contents, such as coffee capsules, the molder should not select ecovio IA1652 solely on the basis of heat deflection temperature. The actual capsule rim, seal, and body geometry must be tested under hot-water or hot-fill conditions because stress relaxation and hydrolytic decomposition compete with thermal distortion. The supplier’s EN 13432 certification does not itself establish food-contact suitability. Users must obtain written confirmation for specific migration limits under Regulation (EU) No 10/2011 or 21 CFR 175.300 where applicable. Published data for this specific configuration is limited, so application-specific migration testing is required.

Published data for long-term storage of ecovio IA1652 at high ambient humidity is limited. The material should be stored in sealed packaging below 30 °C and re-dried after any exposure exceeding 30 minutes in ambient air before processing. The compound is not a home compostable product unless separately certified; the standard industrial composting certification does not automatically transfer to low-temperature backyard conditions. The material should also not be exposed to alkaline fillers or additives that shift hydrolysis equilibrium, because such changes can reduce compostability and molded-part service life. Processors should verify all critical parameters against the current manufacturer certificate of analysis rather than relying on class-typical ranges.