PetroChina Dushanzi HDPE DGDX-6095H is a high-density polyethylene extrusion grade supplied by PetroChina Dushanzi Petrochemical Company. The product is positioned in the high-molecular-weight HDPE segment for applications requiring melt strength, environmental stress-crack resistance, and controlled parison or bubble stability. Typical commercial datasheets list a nominal density of 0.949 g/cm³ determined under ISO 1183-1:2019 and a melt mass-flow rate of 0.9 g/10 min determined under ISO 1133-1:2022 at 190°C with a 5.0 kg load. The grade is produced by a low-pressure ethylene polymerization route and is differentiated from low-molecular-weight HDPE film grades by higher melt viscosity at low shear and improved slow crack growth resistance. The density value corresponds to a semicrystalline morphology with a crystalline fraction near 65% calculated from a two-phase model using amorphous and crystalline densities of 0.852 g/cm³ and 1.000 g/cm³. The complete molecular weight distribution and additive formulation are not disclosed in public technical data; the certificate of analysis for each lot should be consulted for lot-specific melt flow rate, density, ash content, and stabilizer level.

DGDX-6095H should not be specified from melt flow rate alone. The elevated molecular weight fraction influences low-shear viscosity, die swell, and sag resistance in ways that a single MFR value cannot capture. Converters are therefore advised to obtain capillary rheometry data or conduct pilot trials on the intended line before tooling changes are finalized. The grade’s high melt strength is advantageous in blown film and sheet extrusion, but it also raises drive torque and die pressure compared with conventional 0.9 g/10 min HDPE grades possessing narrower molecular weight distributions.

What mechanical performance windows are specified for DGDX-6095H?

The typical values in Table 1 represent product release data generated on compression-molded plaques or extruded sheet and are not design allowables. Mechanical property values vary with specimen preparation, cooling rate, and test temperature. The critical tensile yield stress controls the onset of permanent deformation in load-bearing applications, while the notched impact value indicates resistance to crack initiation at room temperature. When service temperature falls below the ductile-to-brittle transition of the high-molecular-weight HDPE, the failure mode can shift from ductile tearing to brittle fracture, especially in the presence of notches, weld lines, or embedded foreign particles.

The ESCR result is particularly relevant for chemical containers, drainage pipe, and landfill liner service because it captures the material’s resistance to brittle failure under environmental stress. A result above 1,000 h under ASTM D1693-21 Condition B does not guarantee identical performance in every chemical environment; stress-crack resistance depends on detergent concentration, temperature, stress level, and molded-in orientation.

Processing on a grooved-barrel single-screw extruder with an L/D ratio of 33:1 and a barrel temperature profile from 180°C to 220°C typically results in higher melt pressure than a standard 0.9 g/10 min film-grade HDPE because of the high-molecular-weight fraction. Representative pressure rises of 8% to 15% at constant screw speed and die geometry are common; a drive motor with 15% to 20% torque reserve is recommended to prevent screw overload. The die temperature is normally set between 190°C and 230°C, and the melt temperature during continuous runs should remain below 230°C. Sustained operation above 230°C can deplete the antioxidant package, generate oxidized gels, and reduce ESCR. For blown film installations, die gaps of 1.2–1.8 mm and blow-up ratios of 3:1 to 5:1 support stable bubble geometry, but the exact bubble stability window must be verified on the target line because die design and air-ring configuration alter neck height and frost line. Pre-drying is not mandatory at ambient relative humidity below 60%. Granules stored in uncovered outdoor or high-humidity environments should be dried at 80–95°C for 2–4 hours using desiccant dryers when surface moisture exceeds 0.1% by weight.

The stated pressure rise and processing settings are representative ranges derived from general high-molecular-weight HDPE behavior rather than guarantees for a particular production line. Batch-to-batch rheological variation within specification can shift melt pressure by several percent; statistical process control of output rate, melt pressure, and melt temperature is therefore required for thickness-sensitive applications.

When ESCR and long-term hydrostatic strength govern material substitution

DGDX-6095H is specified for extruded sheet, drainage pipe, landfill liner protective layers, industrial chemical containers, and large blow-molded articles in which slow crack growth is the dominant failure mechanism. The typical ESCR value of >1,000 h under ASTM D1693-21 Condition B differentiates the grade from high-flow HDPE injection grades that may fail below 100 h in the same test. However, for pressure pipe service, the resin alone cannot establish a hydrostatic design basis; the final pipe compound must be evaluated under ISO 9080:2012 or ASTM D2837-22 using pipes manufactured on the intended line. In geomembrane applications, DGDX-6095H is typically compounded with carbon black masterbatch to reach a carbon black content of 2.0–3.0% by weight; the finished sheet must meet specific project requirements for oxidative induction time, stress-crack resistance, and thickness uniformity. Where regulatory or project specifications require it, the geosynthetic sheet is tested to GRI-GM13 or an equivalent engineering specification.

Compared with injection-molding HDPE resins having melt flow rates of 20–30 g/10 min, DGDX-6095H has higher melt strength and significantly better environmental stress-crack resistance, but it is unsuitable for thin-wall injection molding because of high pressure drop and freeze-off at reduced wall thickness. Compared with ultra-high molecular weight HDPE grades with weight-average molecular weight above 1,000,000 g/mol, DGDX-6095H retains processability on conventional single-screw extrusion and blow molding lines without requiring ram extrusion or compression molding. Published comparative data for DGDX-6095H against other PetroChina Dushanzi HDPE grades in the same application family is limited; therefore, material substitution should be validated through side-by-side extruder trials and ESCR evaluation on the final part geometry.

Weldability, regrind stability, and additive compatibility

Extrusion welding and hot-plate butt fusion of DGDX-6095H sheet require surface planing to remove the oxidized surface layer. Hot-plate temperatures are typically set between 210°C and 225°C, with joining pressure adjusted according to sheet thickness in the range of 0.15–0.25 MPa. Regrind incorporation up to 20% by weight is generally acceptable when the regrind is dry, free of paper labels and metal fines, and generated from the same grade without repeated thermal history. Higher regrind levels may reduce ESCR below the value required for chemical container or liner service. The resin can be compounded with carbon black, hindered amine light stabilizers, and phenolic antioxidants; however, compatibility with brominated flame retardants and certain metal stearates should be verified by accelerated oven aging or oxidation induction time testing, because acidic residues from these additives can reduce long-term oxidative stability. In coextruded structures, the melt temperature difference between DGDX-6095H and the adjacent layer should be maintained below 20°C to avoid interfacial flow instability and layer thickness nonuniformity.

Quality control for DGDX-6095H is based on the manufacturer’s certificate of analysis, with density and melt flow rate typically measured on every lot and mechanical properties on a periodic or lot-release basis. Converters should establish statistical process control limits for melt pressure, output rate, and sheet thickness because high-molecular-weight HDPE can exhibit lot-to-lot rheological variation even when density and MFR remain within specification. Regulatory compliance is application-specific; the raw resin does not automatically confer food-contact, potable-water, or medical-use clearance. The final compound and conversion line must be assessed against FDA 21 CFR 177.1520, EU Regulation (EU) 10/2011, REACH, and RoHS directives as applicable. Published data for outdoor weathering of unfilled DGDX-6095H in long-term geosynthetic service is limited; accelerated weathering under ISO 4892-2:2013 does not predict field service life without a validated correlation to site-specific exposure conditions.

Operational boundaries that limit processing and end-use

DGDX-6095H is constrained at the lower processing temperature by high melt viscosity and at the upper temperature by thermal oxidative degradation. Sustained melt temperatures above 230°C can deplete the antioxidant package and produce surface gels on extruded sheet or film; short start-up excursions to 240°C should not replace continuous operation at that temperature. The granules should be stored indoors and protected from UV radiation, because prolonged ultraviolet exposure can degrade the outer granule surface and introduce oxidized material into the melt. For outdoor structures, the finished article must include a UV stabilization package and be tested for oxidation induction time according to ISO 11357-6 or ASTM D3895; unfilled natural material does not possess adequate weathering resistance for long-term exposed service. The high molecular weight also limits high-shear injection molding; flow paths with wall thicknesses below 2 mm may exhibit incomplete filling or excessive frozen-in orientation. These operational boundaries are derived from general high-molecular-weight HDPE processing behavior and must be validated on the specific production line and end-use geometry.