Chevron Phillips Chemical HDPE EHM6007 is a high-density polyethylene resin supplied in pellet form for sheet extrusion and subsequent thermoforming. The material is identified by a melt flow rate of 0.65 g/10 min at 190°C under 2.16 kg load when tested to ASTM D1238 and a solid-state density of 0.960 g/cm³ when measured under ASTM D1505. On production-scale sheet lines using single-screw extruders with L/D ratios from 24:1 to 36:1, the grade is processed in the melt temperature range of 200–225°C; at melt temperatures below 190°C, die-lip fouling and surface melt fracture become more frequent on polished chrome rolls, and above 240°C oxidative chain scission reduces melt strength and causes yellow tint in formed parts. The resin occupies an intermediate viscosity position: it is not a high-flow injection molding grade with melt flow rates above 6 g/10 min, nor is it a low-melt-flow extrusion blow molding grade with values below 0.45 g/10 min. Sheet gauges from approximately 1.5 mm to 8 mm are typical for thermoforming operations; thicker sheet requires controlled cooling-roll temperatures to prevent residual stress and centre-line warpage.

Applications are concentrated in industrial thermoformed dunnage trays, equipment covers, reusable distribution trays, and heavy mechanical parts packaging. The density of 0.960 g/cm³ places the grade at the high-stiffness end of the HDPE range and simultaneously reduces environmental stress crack resistance relative to medium-density polyethylene resins with density below 0.945 g/cm³. When chemical exposure is expected, ESCR screening under ASTM D1693 Condition B on the formed part is preferred to pellet-level prediction because wall thickness, forming orientation, and cooling rate influence the crack-initiation time more than the base resin alone. Moisture absorption of HDPE is below 0.01% at 23°C and 50% RH; pre-drying is not generally required, but condensation on chilled pellet surfaces above 60% RH can produce splay and surface defects in extruded sheet. A hopper dryer at 80°C for 2 h is applied on some lines when pellet storage has exposed the resin to outdoor humidity or unheated silo conditions.

What Melt Rheology, Density, and Thermal Data Define EHM6007?

Typical laboratory values for the resin are summarised in Table 1. These values are nominal mechanical and thermal data obtained on standardised specimens and do not replace the lot-specific certificate of analysis for commercial specification.

The melt flow rate of 0.65 g/10 min identifies a relatively high-viscosity melt. Under typical sheet extrusion shear rates of 100–500 s⁻¹, the apparent shear viscosity declines with increasing shear rate in a pseudoplastic manner common to linear HDPE; however, die-layout calculations for coat-hanger manifolds and coextrusion feedblocks should not rely on melt flow rate alone. Capillary rheometry or slit-die extensional viscosity data is required for sheet widths above 1.0 m. The density of 0.960 g/cm³ reflects a high crystallinity contribution, which supports flexural modulus and permeation resistance but increases shrinkage upon cooling. Post-moulding shrinkage of HDPE with this density is generally 1.5–3.0% depending on cooling rate and section thickness; dimensional inspection should be delayed until the formed article reaches ambient temperature and humidity equilibrium. Published rheological data specific to this exact grade are limited; screw and die designs are therefore verified by process trials rather than by extrapolation from melt flow rate alone.

Under tensile loading measured by ASTM D638, yield stress occurs at 29 MPa, followed by cold drawing and elongation to break at 600%. Flexural modulus measured by ASTM D790 is 1,500 MPa. The ductile-to-brittle transition temperature under ASTM D746 is below -75°C, indicating solid-state ductility in slow-rate tests; however, high-speed puncture at sub-zero temperatures is controlled by notch sensitivity, thermoforming residual stress, and sheet thickness, and published values for instrumented puncture under ASTM D3763 are limited for this exact configuration. The Vicat softening point of 124°C under ASTM D1525 provides a comparative thermal-softening boundary for handling and stacking of formed parts, but continuous service at that temperature is not implied.

When EHM6007 Is Compared with Lower-Melt-Index Blow Molding and Higher-Melt-Index Injection Molding Grades

The processing distinction can be mapped through melt flow rate and extruder head pressure. Lower-melt-index blow molding HDPE grades, commonly in the 0.20–0.45 g/10 min range, provide greater melt strength and longer parison hang time but generate higher head pressure and require higher barrel temperatures in extrusion. EHM6007 at 0.65 g/10 min flows with lower motor amperage on a single-screw extruder at 30:1 L/D and permits draw-down of sheet below 2 mm without excessive edge tear under standard roll-stack speeds of 4–10 m/min. By contrast, high-melt-index injection molding HDPE grades with melt flow rate values above 6 g/10 min can fill thin-wall moulds at lower hydraulic pressure, but they do not sustain free-surface sheet extrusion and generally exhibit lower melt strength. EHM6007 therefore aligns with sheet-thermoforming and profile-extrusion HDPE copolymers rather than with injection molding or blow molding resin families. If the grade is substituted for a lower-melt-flow blow molding resin in a converted sheet or profile line, hang-time-sensitive operations, parison wall uniformity, and gear-pump inlet pressure must be revalidated because the lower extensional strain-hardening force changes draw-down behaviour.

Compared with medium-density polyethylene grades with density 0.940–0.948 g/cm³, EHM6007 trades environmental stress crack resistance and notched impact toughness for higher flexural modulus and surface hardness. The resulting parts resist bending deformation under stacking loads but may crack earlier in the presence of polar organic liquids, strong detergents, or aqueous wetting agents at elevated temperatures. If a less stiff medium-density grade has passed existing chemical compatibility tests, replacement with EHM6007 should include a parallel ESCR run under the same test method and coupon geometry rather than an assumption that both grades behave identically.

Sheet Extrusion and Thermoforming Operating Limits

Production-scale sheet lines with barrier screws and bimetallic barrels are typically operated with feed-zone temperatures from 180°C to 190°C, metering-zone temperatures from 200°C to 210°C, and adapter/die zones from 210°C to 225°C. Published product-specific processing data for this grade is limited; these ranges are typical for HDPE sheet of comparable melt flow rate and density, and must be confirmed on the target extruder. Screw cooling in the feed zone may be required to prevent premature melting and solids-conveyance bridging, which appears on the line as melt-pressure oscillation at the breaker plate. Cooling roll stacks are operated at 70–90°C to balance crystallinity and reduce residual stress; lower roll temperatures freeze the sheet surface and increase post-heating warpage, while roll temperatures above 95°C increase sheet adhesion and gauge chatter. In thermoforming, sheet surface temperatures of 130–150°C are typical for EHM6007; surfaces below 125°C produce corner whitening and brittle fracture during drawing, and surfaces above 160°C sag and create gloss variation. Plug-assisted forming with nylon or syntactic foam plugs is used for draw ratios above 2:1 to reduce corner thinning; sheet-edge pinning and adjustable plug speed are required for deep-draw trays and covers.

Extruder melt pressure before the screen changer is a key process variable for this grade. On 30:1 single-screw extruders with barrel diameters of 90 mm to 120 mm, excessive pressure rise across a 100 mesh screen pack signals gel accumulation, carbonised resin, or feed-zone override. The screen pack is typically changed before the pressure differential exceeds 8–10 MPa, although cleanout schedules vary with regrind content and colour concentrate. When high levels of regrind are introduced, the melt flow rate may shift upward because of molecular-weight reduction, and sheet sag during thermoforming can increase. Regrind levels above 30% are widely recognised in sheet extrusion as a point at which melt flow and sag shift measurably; on some lines, radiant heater output is reduced or sheet cooling is increased before the sheet indexes to the forming station.

Compliance status for EHM6007 must be verified against the current Chevron Phillips Chemical product datasheet and supplier certification. In the United States, high-density polyethylene grades of this type are commonly supplied under FDA 21 CFR 177.1520 clearances for olefin polymers; actual food-contact compliance is lot-specific and depends on additives, regrind, and finished-article migration testing. In the European Union, plastic food-contact materials are evaluated under Regulation (EU) No 10/2011, with overall migration and specific migration limits determined on the formed article. Unpigmented polyethylene is generally outside the heavy-metal restrictions of RoHS Directive 2011/65/EU, but colour concentrates, flame retardants, and recycled content must be assessed separately. Under REACH, Article 33 communication applies if a substance of very high concern is present above 0.1% w/w; the safety data sheet Section 15 should be reviewed for current regulatory status before shipment into the European Economic Area.