LLDPE SABIC 118WSJ is a butene-based linear low-density polyethylene film resin supplied with a slip and antiblock additive package. Nominal density is 0.918 g/cm³ under ISO 1183-1:2019, and nominal melt mass-flow rate is 1.0 g/10 min under ISO 1133-1:2022 at 190 °C and 2.16 kg. The grade is used in blown-film and cast-film conversion where down-gauging, seal initiation, puncture resistance, and stable friction behavior are the controlling variables. The six downstream segments that follow are limited to established LLDPE film applications where 118WSJ can be run on conventional single-screw and coextrusion lines without requiring fluoropolymer process aids above standard masterbatch addition levels. Converters should verify lot-to-lot melt-flow variation of ±0.1 g/10 min and adjust barrel temperature profiles accordingly when moving between film gauges below 12 µm and above 120 µm.

What Governs On-Pallet Load Retention When Cast Film Is Downgauged Below 12 µm?

Cast-film trials on 90 mm single-screw extruders with 30:1 L/D and barrier screws show that 118WSJ can be drawn to 8–12 µm at line speeds of 350–600 m/min when the chill-roll temperature is held at 20–32 °C and the die gap is maintained at 0.5–0.8 mm. At these gauges, the limiting defects are web flutter, uneven cling distribution, and die-lip buildup rather than melt fracture. The slip and antiblock package in 118WSJ controls release-layer friction, while cling is developed by 0.5–1.5 wt% polyisobutylene or a low-molecular-weight hydrogenated tackifier compounded into the cling layer of an A/B or A/B/C cast film. A coextruded structure with 118WSJ in the core at 80–90 wt%, a metallocene-catalyzed LLDPE at 10–20 wt% for machine-direction elongation, and a cling layer containing 1.0–2.0 wt% PIB provides on-pallet load retention above 250% pre-stretch on standard wrappers. For machine stretch film, the 118WSJ fraction in the core is maintained at 85–95 wt%, while the skin layer contains 0.8–1.2 wt% antiblock masterbatch to prevent blocking on the finished roll. Terminal products include 17 µm and 20 µm hand pallet wrap, 10 µm machine stretch wrap, and 23 µm extended-core stretch film used in automated logistics lines. Industry compliance for non-food pallet wrap falls under REACH registration and EU Packaging Directive 94/62/EC; for North American retail distribution, peel cling is evaluated under ASTM D5458, and the converter’s quality plan should include a film-thickness profile measured at five points across the web with a tolerance of ±5% of nominal gauge.

In blown-film production for frozen-food form-fill-seal packaging, 118WSJ is blended with LDPE to depress seal initiation temperature and improve bubble stability at BUR 2.5–3.0. The extruder profile is set from feed throat to die at 160–210 °C, with die gap 1.5–2.0 mm and melt temperature held at 190–215 °C. Frozen-food contact requires compliance with FDA 21 CFR 177.1520(c) for olefin polymers under condition of use G, as well as EU Regulation (EU) No 10/2011 with an overall migration limit of 10 mg/dm² or 60 mg/kg where applicable and specific migration limits for the slip and antiblock additives used in the masterbatch. A typical formulation is 70–80 wt% 118WSJ, 20–30 wt% LDPE, and 500–1200 ppm of a synthetic silica antiblock masterbatch; the native slip package in 118WSJ permits a reduction in erucamide masterbatch to 0–0.3 wt%, which avoids excessive bloom on corona-treated surfaces. Corona treatment at 40–45 mN/m is applied before printing or lamination. Terminal products include 30–50 µm frozen vegetable pillow packs, 40–70 µm IQF flow packs, and 35–60 µm layer-separator films for frozen meat patties. Seal jaw temperature for these structures commonly falls at 120–140 °C at 3–5 bar pressure and 0.5–1.0 s dwell, with seal strength above 15 N/15 mm as measured by ASTM F88. Published data for the exact blend of 118WSJ with low-density polyethylene in frozen-food sealing is limited; converters should validate hot-tack using ASTM F1921 on their own seal equipment because slip migration can depress hot-tack at seal initiation.

When Silage Wrap Demands Puncture Resistance Beyond Standard 25 µm LLDPE Films

Coextrusion lines running 70–85 wt% 118WSJ, 15–30 wt% metallocene LLDPE, and 2–3 wt% carbon black/UV masterbatch at total thickness 25–40 µm produce silage wrap and bale-wrap films whose puncture resistance is governed by layer distribution rather than by the base resin alone. The outer white layer contains 1.5–2.0 wt% titanium dioxide plus 0.3–0.8 wt% HALS; the black inner layer contains 2.0–3.0 wt% carbon black; the core contains the highest fraction of 118WSJ plus 10–20 wt% metallocene LLDPE. Melt temperature is maintained at 200–225 °C with a BUR of 2.2–2.8, die gap 1.2–1.8 mm, and frost line height between 4 and 7 die diameters. The terminal product is round bale wrap, clamp-ready silage sheeting, and silage bags. Compliance for silage films is evaluated under EN 13207:2018; the product is not intended for direct food contact, but REACH and EU Directive 2008/98/EC waste-framework obligations apply. A minimum dart impact value of 150 g at 25 µm as measured by ASTM D1709 Method A and an Elmendorf tear value above 100 gf in MD as measured by ASTM D1922 are commonly specified. Field failures are more often tied to additive blooming and UV stabilization loss than to base resin tensile strength; therefore the HALS addition should not be reduced below 0.3 wt% for 12-month outdoor storage in temperate climates. At HALS levels below 0.2 wt%, surface cracking can appear at the bale-wrap folds after 8–10 months of exposure, particularly when the film is stretched above 60% pre-stretch on a round baler.

A sealant web for stand-up pouches and lamination applications employs 118WSJ at a blend ratio of 70–90 wt% with 10–20 wt% LDPE or 5–10 wt% EVA when a lower seal initiation temperature is required. The film is produced by blown-film coextrusion at 30–60 µm, corona treated to 42–48 mN/m, and subsequently adhesive-laminated to polyester or biaxially oriented polypropylene. Compliance for the food-contact sealant layer falls under FDA 21 CFR 177.1520(c) and EU Regulation (EU) No 10/2011, with the converter responsible for establishing overall migration below 10 mg/dm² at the intended package surface-to-volume ratio. Additive addition is typically limited to 500–1500 ppm antiblock and 0–500 ppm slip beyond the native package; using an additional erucamide masterbatch above 0.3 wt% is not recommended because migration to the lamination interface can reduce bond strength. The downstream process includes a laminator running at 150–250 m/min with 2.0–3.5 g/m² solvent-free polyurethane adhesive and a seal strength target above 20 N/15 mm after 24 h cure, using ASTM F88. Terminal product types include stand-up pouch sealant films, sachet lamination webs, and retort-conditioning overprint films where the LLDPE layer is not in direct food contact but is part of the laminate. When retort conditions exceed 121 °C, the converter should evaluate the additive package by total migration testing because the slip and antiblock additives may exceed specific migration limits in high-temperature, high-fat simulants.

Agricultural Greenhouse Film Stabilization and Light-Diffusion Control Parameters

Greenhouse cover films in the 150–200 µm range are produced on blown-film lines using 60–75 wt% 118WSJ, 10–20 wt% LDPE, 5–15 wt% EVA, and 0.4–1.0 wt% of a HALS/UV absorber package. The film is processed at a melt temperature of 195–220 °C, with die gap 1.8–2.5 mm, BUR 2.0–2.6, and frost line height of 6–9 die diameters. EVA raises infrared barrier and heat retention but reduces bubble stability; therefore the LDPE fraction is maintained at not less than 10 wt% to preserve the bubble, and 118WSJ provides impact strength and tear resistance after 12–24 months of exposure. The terminal product is multi-season greenhouse covers, low-tunnel films, and mulching films where a diffusion additive at 1–2 wt% shifts light transmission from direct to diffuse. Compliance for agricultural films is under EN 13206:2017, which specifies thickness, light transmission, dimensional stability, and exposure performance requirements for thermoplastic films used in agriculture and horticulture. The formulation should not contain metal stearates above 1000 ppm if the converter targets a COF below 0.25 after aging; excessive metal stearate can interact with acid-neutralizing additives and reduce UV stabilizer efficiency. Published data under EN 13206:2017 for LLDPE 118WSJ greenhouse films is limited, but the grade’s density and melt-flow rate are suited to the extrusion window when a 24-hour conditioning period at 23 °C and 50% relative humidity is used before physical property testing.

Heavy-Duty Shipping Sack Extrusion Operates at the Upper Gauge Limit

Heavy-duty shipping sacks and industrial liners in the 120–250 µm gauge range require a narrow melt-temperature spread and sufficient bubble stability at BUR 1.8–2.2; 118WSJ is formulated at 85–95 wt% with 5–15 wt% LDPE to stabilize the bubble and reduce haul-off strain. A typical extruder configuration uses a 75 mm grooved-feed single-screw with a 25:1 L/D and a 400 mm die, with temperature zones of 170–210 °C and a melt temperature not exceeding 220 °C. The addition ratio of a slip/antiblock masterbatch is 1–3 wt% depending on desired COF and block resistance; for valve sacks, the outer layer slip level is kept higher than the inner layer to aid filling and palletization. Compliance for non-food industrial packaging falls under REACH and, where applicable, EU Directive 94/62/EC; for export of empty sacks to North America, the converter may need a statement of no heavy metals under the model toxics in packaging legislation. Terminal product types include fertilizer valve sacks, polymer resin bags, and construction-product sacks. The film’s tensile strength in MD and TD is measured by ASTM D882; a common specification for a 150 µm heavy-duty sack is not less than 25 MPa in MD and 22 MPa in TD, with elongation at break above 500%. Because this application runs at the upper limit of the grade’s normal film thickness, bubble cooling air temperature and ambient humidity must be controlled; at ambient relative humidity above 70%, pre-drying at 60–70 °C for 2–4 h is advised to reduce surface moisture defects and bubble instability.