INZEA F2 HTS 655 Rigid 65% Renewable Compostable Polylactic Acid is a rigid polylactic acid compound supplied in pellet form for injection moulding and non-flexible extrusion applications. The grade designation combines a rigid product family with a renewable carbon content claim of 65% as determined by EN 16640 or ASTM D6866; this value refers to the biogenic fraction of total organic carbon and should not be read as a direct weight fraction where inorganic fillers are present. Compostability is assessed under EN 13432 and ASTM D6400, which require ≥90% biodegradation relative to a reference substrate within 180 days, ≥90% disintegration by dry weight after 12 weeks in controlled aerobic composting, and defined ecotoxicity limits in the resulting compost. The material is intended for industrial composting; home composting certification is not implied by the designation unless separately documented.

The 65% renewable designation distinguishes the grade from fully fossil-based styrenic resins and from 100% bio-based PLA formulations. The remaining non-renewable fraction may include hydrolysis inhibitors, heat-stabilizer packages, nucleation aids, processing lubricants, or mineral fillers. The precise formulation is proprietary to the supplier, and the published data for this specific configuration is limited; therefore, incoming-material verification should include melt flow rate, moisture content, density, and, where relevant, renewable carbon certification.

Why Does Moisture Control Dominate Process Stability for This Rigid PLA Compound?

Hydrolysis of the PLA ester backbone is the principal failure mode during melt processing. Drying is mandatory before injection moulding or extrusion. A desiccant hopper dryer with a dew point of -40°C or lower and an inlet air temperature of 80°C for 4 hours is commonly specified for PLA-based rigid grades; residual moisture should remain below 250 ppm as measured by ISO 15512. Moisture above this threshold causes molecular weight reduction, melt viscosity collapse, splay, die drool, and embrittlement in moulded parts. On production-scale equipment, the typical failure signature in thin-wall moulds is gas splay near the gate followed by short shots even when the barrel temperature appears stable.

Barrel residence time should be limited to 5 minutes, and melt temperatures above 230°C accelerate chain scission even in dried material. For injection moulding, cylinder profiles in the range of 175°C to 200°C are common for PLA compounds, with mould temperatures from 25°C to 100°C depending on cycle time, crystallinity development, and dimensional stability requirements. Screw L/D ratios of 20:1 to 24:1 and compression ratios of 2.0:1 to 2.5:1 are typically employed. Vented barrels open to ambient air are generally avoided unless vacuum venting is available, because atmospheric moisture re-enters the melt stream and re-triggers hydrolysis. Batch-to-batch viscosity drift should be monitored by melt volume-flow rate under ISO 1133-1:2022 at 190°C and 2.16 kg; a deviation greater than 15% from the supplier nominal signal requires a check of drying history, residence time, or regrind fraction.

In rigid injection-moulded applications, tensile modulus for PLA compounds in this category typically ranges from 3.0 to 3.5 GPa when tested to ISO 527-2, while notched Izod impact values under ISO 180/1A generally occupy the 2.0 to 4.0 kJ/m² range at ambient temperature. Elongation at break is usually below 5%, confirming brittle failure behaviour. Flexural modulus measured by ISO 178 is often in the same order as tensile modulus. These values are class-typical for rigid PLA compounds; the exact datasheet values for INZEA F2 HTS 655 should be obtained from the supplier and verified on the actual processing line. Candidate rigid uses include disposable serviceware, cosmetic jars, caps and closures, thin-wall technical containers, and non-food housings where industrial compostability is required at end of life.

Thermal Resistance, HDT, and the HTS Designation

Under ISO 75-2 Method B at 0.45 MPa, unmodified PLA typically exhibits heat deflection temperature values of 55°C to 60°C. Heat-stabilized rigid PLA compounds may shift HDT-B into the 70°C to 100°C range through nucleation and controlled crystallinity development, but HDT-A under 1.8 MPa remains lower, often in the 50°C to 60°C band. The HTS suffix in this product is interpreted as an indication of a heat-stabilized formulation rather than a guaranteed HDT value. Published data for this specific configuration is limited; therefore, any continuous-load application above 50°C should be validated on the final article using ISO 75-2 or dynamic mechanical analysis. Vicat softening temperature under ISO 306 Method B50 can provide an additional comparison point for short-term surface heat resistance, but it does not replace HDT or creep testing.

For food-contact use, migration testing on the final article is required under Regulation (EU) No 10/2011 and FDA 21 CFR 175.300. Testing on raw pellets is not sufficient because processing temperature, residence time, and colourant addition can alter the migration profile. End users should request supplier compliance documentation for the specific grade and confirm that the final moulded article has been tested under the intended time-temperature conditions.

Compliance Matrix for Compostability and Food-Contact Verification

The following matrix identifies the standards relevant to specification and compliance assessment. The thresholds shown are standard requirements or common class values for rigid PLA compounds, not certified values for the grade unless explicitly stated in the supplier datasheet.

Relative to amorphous styrenic polymers such as GPPS, this PLA-based rigid compound carries a higher density and narrower processing window. GPPS typically exhibits a density near 1.05 g/cm³, whereas PLA compounds in this class are denser by approximately 18% to 20%. That difference changes shot weight, part weight, and energy consumption per unit volume. Compared with ABS, the PLA compound generally exhibits lower notched impact resistance and more pronounced moisture sensitivity, but it provides industrial compostability that conventional styrenics cannot deliver. The material is not a drop-in replacement for GPPS, ABS, or polypropylene; tooling, drying, melt temperature, cycle time, and end-of-life documentation must be adjusted.

Relative to flexible compostable compounds based on PBAT or starch, the rigid PLA grade has higher tensile modulus, lower elongation at break, and lower tear resistance. It is unsuitable for thin films requiring high puncture or tear energy. Relative to unmodified PLA grades without heat stabilization, the HTS modification is intended to reduce chain scission during repeated heat histories and to improve melt stability in long residence-time operations, although the specific stabilization mechanism is proprietary. The 65% renewable value should not be confused with 100% bio-based certification under programmes such as USDA BioPreferred or OK biobased; the comparable measurement for biogenic carbon is EN 16640 or ASTM D6866, applied to the final formulation rather than to the neat resin alone.

In production-scale injection moulding of this material class, the principal operational boundary is hydrolysis. Regrind can be re-introduced after re-drying, typically up to 20% by weight, but each additional heat history shifts melt flow upward and reduces impact. Accumulated regrind above 30% may produce measurable embrittlement. Storage should be in sealed foil-lined bags at relative humidity below 60%; opened material exposed to ambient air should be consumed within 8 hours unless protected by dry-air conveying. Continuous contact with water above 60°C is outside the typical operational boundary for compostable PLA rigid grades, and the material should not be combined with amine-based masterbatches or additives that can accelerate ester degradation. Tool surfaces should be designed with uniform wall thickness and minimum draft angles of 1° to 2° to reduce ejection stress and warpage.