Indian Oil (IOC) HDPE G-LENE HD50MA180 is a high-flow high-density polyethylene injection-moulding grade supplied as natural-colour pellets under the G-LENE trade name. The grade is positioned for thin-wall rigid packaging, closures, crates, housewares, and general injection-moulded articles where filling pressure and cycle time are process-limiting variables. Its nominal melt mass-flow rate is 18 g/10 min at 190 °C and 2.16 kg load when determined in accordance with ISO 1133-1:2022, and its nominal density is 0.950 g/cm³ at 23 °C measured by ISO 1183-1:2019. Because the melt flow rate is elevated relative to broad-purpose HDPE, the material is particularly suitable for multi-cavity tools with long flow paths and small gates; however, the same feature lowers melt strength and reduces environmental stress crack resistance compared with lower-MFR injection, film, pipe, and blow-moulding grades.

Table 1 summarises representative physical property data published by Indian Oil for HD50MA180. The figures are single-point determinations from injection-moulded specimens and should not be interpreted as batch release limits or as maximum/minimum specifications. Lot-to-lot variation and specimen conditioning can shift individual values, particularly notched impact data.

The molecular architecture of HD50MA180 is based on a linear HDPE backbone with controlled short-chain branching to achieve the 0.950 g/cm³ density. The relatively low weight-average molecular mass implied by the 18 g/10 min MFR produces a short relaxation time and low zero-shear melt elasticity. In high-shear injection filling, the shear-thinning behaviour reduces apparent viscosity and improves flow-length-to-wall-thickness ratios in thin sections. However, the same molecular characteristic prevents the material from developing the melt strength required for stable parison formation or bubble formation in extrusion blow moulding and blown film. Published rheology data for this specific grade is limited, but the MFR value alone indicates a significantly lower zero-shear viscosity than blow-moulding HDPE grades with MFR below 1.0 g/10 min under 190 °C/2.16 kg.

What Distinguishes HD50MA180 from Lower-Flow Injection, Film, and Multimodal Pipe Grades?

Against a lower-flow injection-moulding HDPE with MFR near 8 g/10 min, HD50MA180 reduces pressure drop across sprues, runners, and gates and permits shorter hold-pressure time in thin-wall tools. The trade-off is lower notched impact strength and reduced environmental stress crack resistance. In multi-cavity closure moulds, the higher flow grade can be processed at wall sections from 0.8 mm to 2.0 mm without excessive injection pressure, whereas a lower-MFR grade may require higher melt temperature or higher nozzle pressure and may still exhibit short-shot sensitivity when gate dimensions are small. For applications requiring long-term stress-cracking resistance, low-temperature impact toughness, or creep resistance under sustained load, a lower-MFR HDPE should be evaluated.

Film-grade HDPE with MFR in the range 0.2–1.0 g/10 min is designed for high melt strength, bubble stability, and high blow-up ratios. HD50MA180 is not suitable for blown film because its low melt elasticity promotes bubble sag, draw resonance, and gauge variation. Similarly, blow-moulding HDPE commonly has MFR below 0.5 g/10 min to maintain parison geometry. HD50MA180 cannot be reliably processed on standard extrusion blow-moulding equipment for containers because the parison elongates too quickly under its own mass before mould closure.

Pipe-grade HDPE is frequently a bimodal PE100 with high slow crack growth resistance and hydrostatic design strength classified under ISO 12162. HD50MA180 is not a PE80 or PE100 classification and has no hydrostatic design basis under ISO 9080; it must not be used for pressure pipe, gas distribution, or other long-term hydrostatic load-bearing applications. The difference is structural: bimodal pipe grades contain a high-molecular-mass fraction for toughness and a low-molecular-mass fraction for processability, whereas HD50MA180 is designed primarily for high-flow injection moulding.

On high-speed injection lines equipped with hydraulic accumulators and screws of 25 mm to 50 mm diameter, nozzle melt pressures of 40–80 MPa are typical for wall sections of 1.0–2.5 mm when the melt temperature is maintained at 220 °C. Lower melt temperatures raise viscosity and increase injection pressure; higher melt temperatures reduce melt viscosity but raise the risk of oxidative chain scission. The practical setpoint window in thin-wall closure moulding with hot-runner balance may be constrained to ±5 °C around 215 °C when narrow gate-freeze time is required. Quantitative plant-to-plant comparative data for every competitor grade is not uniformly published; field evaluation under the specific tooling remains necessary.

Pre-drying is not required for sealed bags stored below 60 % relative humidity. When pellet surfaces have been exposed to humid air above that threshold, a desiccant dryer at 70 °C for 2 h is recommended. The nominal melt temperature window is 200–240 °C, with 260 °C as the upper ceiling for short residence times. During interruptions, residence above 240 °C should not exceed 5 min to avoid oxidative yellowing and stabiliser depletion. At melt temperatures above 250 °C, chain scission, generation of oxidised species, and visible yellowing may occur in unpigmented thin-wall parts.

Machine selection should use a general-purpose polyethylene screw with an L/D ratio of 20:1–25:1 and compression ratio of 2.5:1–3.0:1. Hydraulic back pressure should be set at 0.5–1.5 MPa; this is not the melt pressure at the nozzle. Nozzle temperature should be controlled to ±2 °C in thin-wall production with hot-runner systems. In heated sprue bushings, a temperature of 200–230 °C is usual, with lower temperatures causing freeze-off in small gates. Melt cushion should be maintained at 3–5 mm to prevent cushion loss and gate pressure fluctuation during screw recovery.

Mould temperature should be maintained between 15 °C and 50 °C. Higher mould temperatures improve surface gloss and reduce orientation stresses but add cycle time. Free-flowing gate geometries are preferred: edge gates or direct hot-runner valve gates with land lengths of 0.5–1.0 mm for closure and cap applications. Vent depths for high-density polyethylene typically range from 0.01 mm to 0.02 mm; inadequate venting results in burn marks, mould deposits, and short shots at the end of fill. Linear mould shrinkage for this grade is generally 1.5–2.5 % parallel to flow and 1.5–2.0 % perpendicular to flow for wall thicknesses of 2.0 mm; the exact value depends on mould temperature, gate location, packing pressure, and wall-thickness distribution.

The grade is used in thin-wall rigid packaging, caps and closures, crates, housewares, paint-pail lids, and similar injection-moulded articles. In caps and closures, it is regularly processed in multi-cavity hot-runner tools because the 18 g/10 min MFR supports fast filling of small gates. In pails and crates, the material provides stiffness from its 0.950 g/cm³ density, but should not be used for load-bearing structural articles at sub-zero temperatures without notched impact testing. For food-contact articles, the fabricated part must be tested against regional regulations; the base polyolefin may be evaluated under FDA 21 CFR 177.1520 or EU Regulation 10/2011, but compliance is article-specific and depends on additives, colourants, and process residues.

Thermal Boundary and Incompatibility Thresholds

HD50MA180 is not stabilised for long-term outdoor exposure. Parts exposed to ultraviolet radiation can exhibit surface chalking, gloss loss, and reduction in tensile elongation unless an adequate UV stabiliser package or carbon black is added. The grade is also not recommended for pressure pipe because it lacks PE80/PE100 classification; there is no ISO 9080 hydrostatic design basis. It should not be combined with high levels of polypropylene-rich regrind beyond 3–5 % unless mould trials confirm no delamination and no unacceptable loss in notched impact strength.

Chemical resistance is typical of high-density polyethylene: resistant to many aqueous acids, alkalis, and polar solvents at temperatures below 60 °C, but aromatic hydrocarbons, chlorinated solvents, and strong oxidising acids can cause swelling, stress cracking, or oxidative degradation. For aggressive chemical service, environmental stress crack resistance testing according to ASTM D1693-22 and immersion testing under the intended service concentration should be performed before specification approval.

Processing above 260 °C can lead to chain scission, viscosity reduction, and generation of oxidised species; molten resin should not be held above 240 °C for longer than 5 min. Combustion of degraded HDPE can produce acidic and hydrocarbon vapours, so local exhaust ventilation is required during purging or extended high-temperature shutdowns. The grade should be stored away from direct sunlight and strong oxidising agents, with sealed bags kept below 60 % RH to avoid moisture uptake and surface condensation. These limits are operational boundaries rather than exhaustive certifications.