Chevron Phillips Chemical HDPE 9302 is processed on grooved-feed single-screw blown film extruders with screw L/D ratios between 25:1 and 30:1 for the manufacture of thin-gauge T-shirt grocery sacks, where the high-molecular-weight distribution supplies bubble stability at film gauges between 10 µm and 25 µm and at die outputs above 4.5 kg/h per cm of die circumference. Compliance in this segment references ASTM D4976-23 for polyethylene extrusion materials, ASTM D882-22 for tensile properties at 500 mm/min, ASTM D1709-22 Method A for dart drop impact, and ASTM D1922-23 for Elmendorf tear resistance. The formulation is controlled to 97.0–100.0 wt% HDPE 9302, with a slip agent masterbatch added at 0.5–1.5 wt% when the static coefficient of friction must remain below 0.35; a color masterbatch is metered at 1.0–4.0 wt% depending on pigment loading, and an antiblock masterbatch is introduced at 0.5–1.5 wt% for films stored in stacked wound rolls. Processing uses a die gap of 1.2–1.8 mm, a blow-up ratio of 3.0:1 to 4.5:1, and a frost line height between 8 and 12 die diameters; melt temperatures of 190–230 °C at the die and internal bubble cooling air volumes adjusted to maintain frost line stability of ±15 mm are typical. Terminal product types include T-shirt grocery sacks, produce bags, thin merchandise bags, and lower-gauge consumer refuse sacks.

Which Melt Fracture Threshold Defines the Upper Output Limit for HDPE 9302 on Low-Stalk Lines?

On low-stalk blown film lines, HDPE 9302 is converted into heavy-duty industrial liners and multi-material containment webs in thicknesses from 20 µm to 80 µm. The upper output limit is governed less by motor load than by the onset of sharkskin melt fracture at the die exit; converters maintain apparent die exit shear stresses below 0.14 MPa by adjusting die land temperature and die gap. Because published data for this specific grade configuration are limited, incoming lots are qualified by melt index per ASTM D1238-23 at 190 °C/21.6 kg and by capillary rheometry per ASTM D3835-23. Compliance for heavy-duty industrial liners commonly references ASTM D4976-23, ASTM D1709-22 Method B, ASTM D1922-23, ASTM D882-22, and ISO 527-3:2018; where liners enter UN-certified packaging, 49 CFR 178.511 and ISO 16495 may additionally apply. Formulation ratios in heavy-duty can liners are typically 95.0–98.0 wt% HDPE 9302 with 0.5–1.0 wt% fluoropolymer processing aid masterbatch, 1.5–3.0 wt% carbon black masterbatch where UV opacity is specified, and 0.3–0.8 wt% antistat masterbatch for dry goods packaging. On 65 mm grooved-feed extruders with L/D 30:1, discharge temperatures of 200–225 °C, die head pressures of 35–55 MPa, and output rates of 250–350 kg/h are used. The low-stalk bubble is stabilized with a dual-lip air ring and internal bubble cooling at a blow-up ratio of 2.5:1 to 3.5:1 and a frost line height of 4–7 die diameters. Terminal product types include construction debris liners, industrial can liners, healthcare waste liners, and heavy-gauge mailer envelopes.

Dry food inner webs based on HDPE 9302 are produced as 12–30 µm blown films in which the resin is used at 95.0–99.5 wt%. The food-contact status is governed by 21 CFR 177.1520(c) 3.1a in the United States and by Regulation (EU) No 10/2011 in the European Union; overall migration is verified according to EN 1186-1 with a limit of 10 mg/dm² for general food simulants. All additive masterbatches must be selected from applicable positive lists, and manufacturing practice must meet 21 CFR 174.5.

Slip masterbatch addition in this segment is limited to 0.5–1.0 wt%, typically erucamide-based, with a synthetic silica antiblock loaded at 0.3–0.8 wt%. Color masterbatch addition is typically 1.0–2.0 wt% for white or printed webs. Process conditions use die gaps of 1.4–1.8 mm, a blow-up ratio of 3.0:1 to 4.0:1, melt temperatures of 190–215 °C, and corona treatment to 38–42 mN/m for lamination or flexographic printing. Terminal product types include cereal liners, cracker pouches, dry-soup sachets, and bakery overwrap films.

Coextruded Three-Layer Can Liners With PCR Core and HDPE 9302 Skins

In three-layer coextrusion, HDPE 9302 is positioned in the skin layers of A/B/A can liner structures where the core carries post-consumer recycled HDPE or post-industrial regrind. The skin layers are each maintained at 20–35 wt% of total film mass, the recycled core at 30–55 wt%, and the balance is carried by whitener or color masterbatch at 1.0–2.0 wt% where opacity is specified. A fluoropolymer processing aid is introduced at 200–500 ppm across total throughput only when extruder screw speed creates surface melt fracture. Compliance testing follows ASTM D4976-23 for material consistency, ASTM D1709-22 Method B for dart impact, ASTM D1922-23 for tear, ASTM D882-22 for tensile properties, and ISO 14021 for any recycled-content claim communicated to buyers. On 100–150 mm three-layer blown film dies with concentric A/B/A distribution, the die gap is held at 1.6–2.0 mm, the blow-up ratio at 2.5:1 to 3.5:1, and the melt temperature at 190–220 °C; the core extruder is commonly run 10–15 °C lower than the skin extruders to limit degradation of post-consumer material. Bubble cooling uses a dual-lip air ring with internal bubble cooling to maintain gauge variation below ±8%. Terminal product types include institutional can liners, refuse bags, and utility liners.

In multi-wall paper bag liner production, HDPE 9302 is extrusion-blown into 25–60 µm webs that are inserted as the innermost ply of 3–5 ply paper sacks for dry pet food, feed ingredients, and powder chemical packaging. Compliance references ASTM D882-22 for tensile properties, ASTM D1922-23 for tear, and TAPPI T 437 for bag seam strength; where the filled sack must meet UN performance requirements, the complete bag is tested under 49 CFR 100–185. Formulation ratios are 96.0–100.0 wt% HDPE 9302, 0.5–1.5 wt% slip masterbatch, 0.3–0.8 wt% antiblock masterbatch, and 1.0–2.0 wt% opacity masterbatch. The process employs high-stalk extrusion with a die gap of 1.5 mm, a blow-up ratio of 3.0:1, and gauge variation held to ±5%; liner rolls are supplied at 250–1000 mm width. Terminal product types include pet food bag liners, powdered chemical liners, and seed or food ingredient liners.

When HDPE 9302 Is Drawn Below 15 µm, What Dart Impact and Elmendorf Tear Should the Converter Verify?

Below 15 µm on high-stalk lines, HDPE 9302 enters a property cliff-edge region where gauge non-uniformity above ±10% produces disproportionate failure rates in automated bagging operations. The converter verifies dart drop impact and Elmendorf tear rather than relying on nominal gauge alone because tear propagation is sensitive to frozen-in orientation and frost line position. Incoming resin lots are qualified by ASTM D1238-23 at 190 °C/21.6 kg and ASTM D1505 for density; film testing follows ASTM D1709-22 Method A, ASTM D1922-23, and ASTM D882-22. The formulation typically contains 98.0–100.0 wt% HDPE 9302, with 0.3–0.8 wt% slip masterbatch and 0.3–0.6 wt% antiblock masterbatch; processing aid is added at 200–500 ppm only if melt fracture appears at high screw speeds. Process conditions use a die gap of 1.0–1.4 mm, a blow-up ratio of 4.0:1 to 5.0:1, melt temperatures of 195–215 °C, high-stalk heights of 10–14 die diameters, and dual-lip air ring cooling with internal bubble cooling. Output is held at 3.5–5.0 kg/h per cm of die circumference to balance quench rate against bubble stability. Published data for this specific configuration are limited; converters qualify the edge by producing a gauge ladder across 10–18 µm and testing dart impact, Elmendorf tear, and CD tensile at each step. Terminal product types include ultra-thin produce bags, dry cleaning bags, and high-count merchandise sacks.