On production-scale blown film lines equipped with grooved-feed extruders of 65–90 mm diameter and L/D 30:1, CHN Energy Yulin LDPE 2426H is processed as a neat resin for general-purpose packaging film in the 25–80 µm thickness range. The nominal melt mass-flow rate of 2.0 g/10 min at 190 °C/2.16 kg, determined in accordance with ISO 1133-1:2022 or ASTM D1238, positions the grade for stable bubble formation without the draw resonance observed in higher-MFR coating grades. Nominal density of 0.924 g/cm³ at 23 °C, measured by ISO 1183-1:2019 or ASTM D1505, provides a balance between stiffness and tear resistance. In the blending step, 1.5–2.5 wt% of a 5 wt% erucamide/synthetic silica slip-antiblock concentrate is metered at the feed throat to reduce blocking in wound rolls. Direct dosing of pure amide is not recommended because it can cause screw slippage and feed-throat fouling. Barrel temperature profiles are set between 160 °C and 190 °C, with the die zone held at 170–185 °C and melt temperature at the die lip not exceeding 190 °C to avoid oxidative gel formation. A die gap of 0.8–1.4 mm combined with a blow-up ratio of 2.0:1–2.8:1 and a frost-line height of 6–8 die diameters is maintained on air-cooled monolayer lines. Bubble stability is governed by the extensional viscosity of the resin; increasing frost-line height beyond 10 die diameters produces excessive film curvature that destabilises the collapsing frame and creates gauge bands. Film tensile properties tested per ASTM D882 typically fall within 12–18 MPa machine-direction stress at break and 400–600% elongation at break, depending on frost-line position and winding tension. The extruder motor load is commonly held at 70–85% of rated torque, and melt pressure before the screen changer is maintained below 34 MPa to prevent premature screen pack loading. Compliance for direct food contact is evaluated under FDA 21 CFR 177.1520(c) 2.1 for olefin polymers and under EU Regulation (EU) No 10/2011, with overall migration limits below 10 mg/dm². Terminal products include lightweight carrier bags, garment bags, bread bags, and industrial liners.

What Determines Peel Strength When LDPE 2426H Is Extrusion-Coated onto Paper and Aluminium Foil?

Extrusion coating onto paper and aluminium foil uses LDPE 2426H at a coating weight of 15–40 g/m². Melt temperature in the coat-hanger die is raised to 290–315 °C, which is above the standard blown-film range, in order to oxidise the web-contact surface and form polar carbonyl groups that interact with aluminium oxide or corona-treated paper. Peel strength is measured according to ISO 11339:2022 at a crosshead speed of 100 mm/min. In production, 100 wt% LDPE 2426H is common for paper-based sugar sachets and aluminium foil lidding, while 10–20 wt% of an autoclave LDPE or metallocene LLDPE may be added when the coating line requires lower neck-in at high draw ratios. Downstream processing requires ozone treatment of the melt curtain at 0.4–0.6 L/min ozone in air and a chill-roll temperature of 12–18 °C to prevent blocking and to stabilise coating weight uniformity. Edge neck-in measured from the die width is held between 6% and 12%, and the draw ratio from die gap to coating thickness is typically 50:1–100:1. Chill-roll surface finish, usually matte chrome with Ra 0.8–1.2 µm, controls the backside coefficient of friction and affects winding tension on the rewind section. Adhesion to aluminium foil without primer is time-dependent; maximum peel strength is reached after conditioning for 24 h at 23 °C and 50% relative humidity. If melt temperature drops below 280 °C, adhesion falls sharply due to insufficient surface oxidation, and the coated structure may delaminate at flex points. LDPE 2426H is not suitable for retort-grade lidding because the polyethylene layer softens above 95 °C, and it should not replace PP-based coating in packages requiring sustained thermal resistance above 110 °C. Terminal products include aseptic beverage carton inner layers, paper-based sachets, and aluminium foil lidding for dairy products.

Shrink Hood Film: Orientation Memory and Sealing Response

Shrink hood film for pallet load stabilisation consumes LDPE 2426H in thicknesses of 100–250 µm, where orientation memory and seal integrity are the controlling properties. The resin is blended at 70–80 wt% with 20–30 wt% octene-based linear low-density polyethylene to broaden the sealing window and increase machine-direction tear resistance, as measured by ASTM D1922. Film is produced on high-stalk blown film towers with blow-up ratios of 3.0:1–4.0:1 and die gaps of 1.2–2.0 mm, which biases orientation toward the transverse direction. Stalk height is kept between 8 and 12 die diameters, because shortening the stalk increases melt sag and produces uneven shrink force distribution. Free shrink in hot air at 150 °C, tested per ASTM D2732, typically reaches 15–25% in the machine direction and 25–35% in the transverse direction, depending on stalk configuration and frost-line temperature. Shrink force must remain below the compressive strength of the packed goods; therefore, gauge control tolerance is held to ±5% around nominal film thickness. Sealing is performed by impulse or hot-bar sealers with seal bar temperature of 120–140 °C and seal dwell time of 0.8–1.6 s, because the LDPE-rich film has a lower seal initiation temperature than LLDPE-rich alternatives. The finished hood film is applied by automatic bagging machines at 80–140 packs/h, and the hot-air shrink tunnel operates at 160–190 °C with residence time of 14–24 s. Storage of finished hood film above 35 °C is not recommended, since partial relaxation of orientation can occur before final heat shrinking, causing loose wraps on tall pallet loads. Bubble cage spacing during production is normally set at 1.2 times the die diameter to prevent tube wander and creasing under high transverse orientation. Terminal products include shrink hoods for cement bags, insulation rolls, and beverage multipacks.

Agricultural silage cover and mulch film extrusion with LDPE 2426H as the base resin requires carbon black or titanium dioxide masterbatch addition at 6–10 wt% to achieve ultraviolet stabilisation sufficient for 6–12 months of outdoor exposure. The material is processed on air-cooled blown film lines with a 70–90 mm extruder, die gap of 1.0–1.6 mm, and blow-up ratio of 2.2:1–3.0:1. In silage cover applications, film thickness is 120–200 µm, and erucamide slip additive is deliberately omitted because a high coefficient of friction is needed to prevent the cover from shifting on the silage clamp. Film surface is corona-treated to 38–42 mN/m when printing is required for batch identification and traceability. For mulch film, thickness is reduced to 12–25 µm, and EVA or metallocene phases are not used; LDPE 2426H is drawn down at a low melt temperature of 150–170 °C to maintain bubble stability at thin gauge. The compound must comply with REACH Annex XVII restrictions on polycyclic aromatic hydrocarbons and with GB 4806.1-2016 if the silage film contacts animal feed. Carbon black masterbatch used in this structure should have volatile content below 0.2 wt% and particle size below 25 µm to avoid screen pack pressure rise beyond 2 MPa during a 48 h production run. The molecular weight distribution of LDPE 2426H permits film recovery rates of 400–600 m/min, but line speed is limited by the collapsing frame over 800 mm die diameter because of surface blocking in high-ambient-temperature environments. This grade is not recommended for direct contact with silage effluent for extended periods, because plasticiser migration from the film matrix may occur under anaerobic conditions. Terminal products include silage clamp covers, round bale stretch wrap, and low-density mulch films for weed control.

When LDPE 2426H Is Used as the Sealant Layer in High-Speed Form-Fill-Seal Systems

On vertical and horizontal form-fill-seal lines running at 60–120 packs/min, LDPE 2426H functions as the sealant ply in three-layer coextruded films, where the core layer may contain HDPE or metallocene LLDPE for stiffness and puncture resistance. The sealant layer comprises 90–100 wt% LDPE 2426H, with the balance being a plastomer or an ethylene-vinyl acetate copolymer at 10 wt% or less to lower seal initiation temperature when cold product is packed. Seal initiation temperature for this MFR class is typically observed between 105 °C and 115 °C when measured by ASTM F1921, and plateau seal strength at 140 °C is 15–25 N/25 mm under ASTM F88. Published data for this exact CHN Energy grade under all seal conditions is limited, so the cited range should be verified against the certificate of analysis for the specific batch. The three-layer die gap is set at 1.2–1.8 mm, and the sealant layer thickness is maintained at 15–25% of total film thickness because the sealant ply must not flow excessively during sealing. Hot-tack performance is measured with a 0.5 s seal dwell and 200–400 g load, and hot-tack force over the 100–140 °C range is the determining parameter for packages that are filled and sealed vertically. If the sealant layer contains more than 10 wt% LDPE 2426H with a melt flow rate below 2.0 g/10 min, seal initiation becomes too high for high-speed operations, so blending ratios are checked by online melt index measurement. The sealant ply must be corona-treated to 36–40 mN/m before lamination, but the treated surface must not face the sealing jaw, as treatment by-products can cause erratic seal strength. Incompatibility is observed with ionomer-based sealants and with packages requiring retort conditions above 110 °C, where LDPE 2426H cannot maintain seal integrity. Terminal products include confectionery pillow packs, frozen food bags, and powdered beverage sachets.

Heavy-Duty Sack and Liner Extrusion Without Film Blocking

Heavy-duty liners and industrial sacks extruded from LDPE 2426H are produced at 80–200 µm thickness on lines with internal bubble cooling and segmented air rings for gauge control. The blend is 95–100 wt% LDPE 2426H with 2–4 wt% of a 10 wt% erucamide/silica masterbatch to reduce blocking without increasing haze beyond 10% measured per ASTM D1003. Processing uses a die gap of 1.4–2.2 mm, blow-up ratio of 1.8:1–2.5:1, and melt temperature of 170–185 °C. Internal bubble cooling air is held at 15–20 °C, which raises output by 20–30% compared with external cooling only. The extruder barrel is purged with LDPE 2426H before startup, and the screen pack is 100/150/200 mesh to remove agglomerated silica that would otherwise form film fisheyes above 0.6 mm. Falling-weight impact strength per ASTM D1709 method A is evaluated at each batch change, with typical results in the 120–220 g range for 100 µm film. Tear resistance per ASTM D1922 is anisotropic; machine-direction tear is lower than transverse-direction tear, so the sack opening direction is designed with the transverse direction along the load path. The film is not intended for direct contact with aromatic solvents, chlorinated hydrocarbons, or strong oxidising acids, because these chemicals swell or stress-crack LDPE at ambient temperature. Compliance for industrial packaging is assessed under the UN Model Regulations if the sack is used for dangerous goods; the film alone does not confer UN certification, and the converted sack must pass drop and stack tests per 49 CFR 178 or ADR. Terminal products include heavy-duty pallet liners, fertiliser sacks, and construction debris bags.