Hanwha TotalEnergies HDPE C912A is a high-density polyethylene grade developed for extrusion blow moulding of rigid packaging and industrial containers. The model designation C912A identifies a specific stabilizer package, melt-flow window and molecular architecture within the manufacturer’s HDPE portfolio. Supplier technical documentation classifies the resin as a general-purpose blow moulding grade with a density controlled around 0.956 g/cm³ when measured under ISO 1183-1 or ASTM D1505. A standard melt mass-flow rate of 0.30 g/10 min at 190°C under 2.16 kg load and a high-load melt mass-flow rate of 9.0 g/10 min under 21.6 kg load define the flow ratio used by converters to infer parison sag behaviour. The high-load value is the more operationally significant parameter because it correlates with die-head pressure, parison drawdown and wall-thickness distribution in accumulator and continuous-shuttle machines.

The grade is differentiated from injection-moulding HDPE by its low standard melt index and from thin-gauge film grades by its higher melt strength. Typical application envelopes include household chemical containers, liquid detergent bottles, industrial jerry cans up to 5 L, and small to medium rigid packaging where elevated flexural modulus and environmental stress-cracking resistance are required. Published data for this specific configuration is limited for high-pressure gas pipe service and for direct contact with aggressive aromatic solvents above 40°C; such uses require separate validation programmes.

What Differentiates C912A from Higher- and Lower-Flow HDPE Grades?

Compared with high-density polyethylene grades having a high-load melt index above 15 g/10 min, C912A retains a higher elongational viscosity at typical die exit temperatures of 170°C to 200°C. This translates into reduced parison sag for containers with shot volumes up to approximately 5 L and consistent weld-line integrity at pinch-off. Compared with low-flow grades having a high-load melt index below 6 g/10 min, C912A reduces extrusion backpressure on single-screw machines with a barrel length-to-diameter ratio of 24:1 to 30:1, permitting lower melt temperatures and reduced energy input per kilogram. The molecular weight distribution is not published as a unimodal or bimodal specification; however, the ratio of high-load to standard melt flow rates indicates a medium-to-broad distribution that supports both shear thinning and parison strength.

The grade is differentiated from general-purpose injection-moulding HDPE not only by melt viscosity but also by downstream processing route. Injection grades typically operate at melt temperatures from 220°C to 260°C, whereas blow moulding grades must retain parison integrity at 190°C to 210°C. Substitution of a high-flow injection grade into blow moulding equipment can lead to wall-thickness fluctuation, parison sag and pinch-off weld failure. Conversely, substitution of C912A into injection moulds without verification of short-shot behaviour and gate freeze time is not recommended. The calcium stearate/antioxidant package is formulated for long residence-time extrusion rather than for thin-gauge continuous film, so blown film processors must evaluate gel count and draw resonance separately.

The representative datasheet values below are consolidated from supplier technical documentation and are subject to lot-level certificate-of-analysis control.

Melt Pressure, Parison Kinematics and Screw Configuration

On single-screw continuous shuttle machines with screw diameters of 65 mm to 90 mm and length-to-diameter ratios of 24:1 to 30:1, a typical barrel profile for C912A begins at 175°C to 185°C in the feed zone and rises to 200°C to 215°C at the die head. The die gap is normally set between 1.5 mm and 2.5 mm for monolayer containers, with parison programming profiles adjusted to compensate for upper-wall thinning at shot weights above 1.5 kg. Accumulator-head machines require a melt temperature of 190°C to 210°C and an accumulator drop time of 2 to 5 seconds depending on tool size. Clamp force for a 5 L jerry can is commonly 30 to 50 metric tons per cavity, based on parting-line length and flash thickness.

Screw geometry should be selected to limit melt temperature rise to less than 5°C across the metering zone at 100 min⁻¹ screw speed. A barrier screw with a dispersive mixing element is preferred for regrind-containing feed; a compression ratio of 2.2:1 to 2.8:1 is typical. Backpressure is maintained at 0.5 MPa to 1.0 MPa to homogenize melt but should not exceed 1.5 MPa, because excessive backpressure increases shear heating and shifts the melt index upward.

Parison programming influences final wall thickness more than barrel temperature. For a 1 L bottle with a target wall thickness of 0.6 mm at the lower sidewall, the die gap is typically programmed to open 20% to 40% above nominal during the upper-parison segment and close to 70% of nominal during the tail segment. The exact programme depends on the accumulator head geometry, the presence of a diverging die bushing and the pinch-off flash allowance. Die swell is controlled by profiling die land length from 10 to 25 times the die gap, and blow air pressure is maintained between 0.6 MPa and 0.8 MPa.

At a production-scale evaluation on a 75 mm grooved-feed extruder producing 1 L detergent bottles, batch-to-batch die-head pressure at 190°C varied by less than 1.2 MPa across 24 lots with regrind content held at 15 wt%. Melt temperature measured at the die exit remained between 198°C and 203°C, and wall-thickness standard deviation in the sidewall was 0.04 mm at a target of 0.6 mm. Increasing regrind to 25 wt% widened the sidewall thickness range to 0.09 mm and shifted the high-load melt index by 8%, indicating that regrind concentration rather than pellet lot variation is the dominant cause of process drift.

In household chemical packaging, C912A is selected where the finished article must pass drop-impact testing at -20°C and resist environmental stress cracking from surfactant-containing formulations. The ESCR value above 600 h under ASTM D1693 condition B provides a wide margin over grades with ESCR below 100 h, but it is not a substitute for full bottle testing in the actual fill solution. For food-contact grade containers, processors must validate migration under EU 10/2011 overall migration limit of 10 mg/dm² and the specific food simulant conditions, because pellet data alone cannot certify the blow moulded article after colour concentrate and regrind addition.

Industrial jerry cans up to 5 L benefit from a flexural modulus of 1,260 MPa, which supports wall-thickness reduction only when top-load performance is revalidated according to ISO 12048 or equivalent compression-test method. A reduction in nominal sidewall thickness below 0.8 mm requires additional drop-impact testing because orientation and pinch-off weld quality exert a stronger influence than pellet impact properties. Observed failure modes on production-scale blow moulding of C912A include parison curl caused by uneven die temperature around the mandrel, weld-line splitting at the pinch-off due to excessive flash thickness, and pinholes from moisture or regrind contamination. Parison curl is corrected by centering the mandrel within 0.05 mm total indicated runout. Weld-line splitting is mitigated by increasing pinch-off land radius and reducing flash thickness to below 0.2 mm at the cutting edge.

When Moisture, Shear and Residence Time Interact in Blow Moulding

Surface moisture on incoming pellets at storage humidity above 60% RH can produce splay, pinholes and inconsistent parison inflation. Drying for 2 h at 80°C with a desiccant dryer is generally sufficient, but only condensed surface moisture is removed; pellets exposed to liquid water require longer residence time. Melt temperatures above 230°C accelerate oxidation and shift the melt index upward through chain scission. In accumulator machines with long hold times, a melt temperature above 220°C may cause yellowing at the die lip within 20 min of stagnation.

High-shear extrusion at screw speeds above 120 min⁻¹ on a 65 mm screw can generate melt temperatures in excess of 230°C even with the barrel set at 190°C. This occurs because the low standard melt index generates viscous dissipation. The practical working window is therefore defined not only by barrel setpoints but by the combination of screw speed, backpressure and melt temperature. Operators should monitor die-head pressure continuously; a drop of more than 1.5 MPa at constant output suggests melt index drift, degraded regrind or contamination with a lower-viscosity polymer.

Regrind addition above 30 wt% is not recommended for containers that require drop-impact testing at -20°C. Multiple heat histories broaden the effective molecular weight distribution and can create brittle domains near the pinch-off weld. Blending C912A with off-spec HDPE of unknown catalyst origin is not advised because titanium or chromium residues from different catalyst systems can alter the consumption rate of the stabilizer package and shift the oxidative-induction time under ISO 11357-6. Combination with amine-based antistatic agents or certain hindered amine light stabilizers may antagonize the phenolic oxidation package and reduce long-term thermal stability. Such additive combinations require an oxidative-induction time comparison at 200°C and a yellowness index check under ASTM D6290 before full-scale conversion.

Incoming lot verification commonly includes melt mass-flow rate according to ISO 1133-1 and density according to ISO 1183-1. A lot is accepted only when density falls within ±0.002 g/cm³ of the target and the high-load melt index falls within ±0.5 g/10 min of the supplier target. These two measurements are insufficient to detect all stabilizer package variability; oxidative-induction time under ISO 11357-6 at 200°C is recommended for lots intended for long-residence-time processing or high-ambient-temperature warehouse storage.

Compliance claims for a blow moulded article are article-specific. The following matrix identifies the standard anchors commonly referenced for C912A-containing monolayer containers.

Published data for this specific configuration is limited for oxygenated solvent packaging above 40°C and for long-term UV-stabilized outdoor furniture. In such cases, a validation programme based on ASTM D256 notched impact at -20°C, ASTM D1693 ESCR, and ISO 4892-2 xenon-arc weathering is required before product transfer.