Relene LLDPE FS19020 is an extrusion-grade linear low-density polyethylene based on butene comonomer, with nominal density in the 0.918–0.922 g/cm³ range and melt flow rate of 1.8–2.2 g/10 min determined under ASTM D1238 at 190°C/2.16 kg. The resin is supplied as natural pellets without slip or antiblock; additive incorporation is carried out at the converting line. The following application profiles are organized by downstream processing route, formulation ratio, compliance position, and terminal film structure.

Cast stretch film lines running at 280–450 m/min with primary chill roll temperatures between 20°C and 40°C use FS19020 as the main elastic component in 12–20 µm machine wrap and hand wrap. The resin is fed to a single-screw extruder with 30:1 L/D ratio and barrier screw geometry; melt temperature at the die exit is held in the 240–260°C window, while excursions above 270°C reduce cling retention by accelerating migration of tackifier from the film core to the surface without adequate quench. Typical formulation is 85–92 wt% FS19020, 5–10 wt% high-pressure LDPE with density 0.923–0.925 g/cm³ to increase melt stiffness, and 1–3 wt% polyisobutylene-based cling additive masterbatch introduced at the feed throat. Surface cling is measured against a stainless steel sled under ASTM D1894; target values for pallet wrap fall at 0.15–0.35 on the outer face and 0.35–0.55 on the inner face depending on pre-stretch ratio. Pre-stretch ratios above 200% demand machine-direction elongation at break above 300% under ASTM D882. Thickness variation across the die is controlled by automatic air knife adjustment to below ±2%. Blocking resistance after 35°C warehouse aging is tested under ASTM D3354 because roll-to-roll blocking can occur when cling migration is excessive. REACH registration of the resin under 1907/2006 applies for industrial stretch film sold in the European Economic Area; the grade is not specified for direct food contact unless the converter validates a functional barrier with a separate food-contact layer. Terminal products include 300 mm and 500 mm hand wrap rolls, rotary ring machine wrap, and coreless stretch film for automated palletizers.

Heavy-Duty Sack Liner Extrusion with Shrinkage Control

Blown film lines producing 80–120 µm heavy-duty shipping sacks from FS19020 use spiral mandrel dies with die gaps of 1.8–2.4 mm and dual-lip air rings with internal bubble cooling. Blow-up ratio is set at 2.2–2.8:1, and frost line height between 450 mm and 700 mm above the die controls machine-direction orientation and layflat stability. A blend of 20–30 wt% LDPE with melt flow rate 0.25–0.35 g/10 min improves bubble stability on high-output lines, while 0.5–1.0 wt% slip agent and 0.3–0.8 wt% synthetic silica antiblock are added when sack liners require low insertion friction. Pre-drying of the base resin is not normally required, but additive masterbatches with carrier resins containing absorbed moisture above 300 ppm are dried at 60–70°C for 2–4 h before introduction into the extruder. Dart impact measured under ASTM D1709, Method A, is specified above 200 g for 100 µm film at 23°C; cold-weather qualification should confirm that impact retention at –10°C remains acceptable for the intended logistics chain. Elmendorf tear under ASTM D1922 shows anisotropic behavior, with machine-direction tear values commonly 15–25% lower than transverse-direction values because molecular orientation concentrates in the machine direction. Published data for low-temperature puncture on this exact FS19020 blend at 100 µm is limited; converter-side qualification under the final sack specification is required before release. Terminal products include FIBC inner liners, chemical powder shipping bags, mineral aggregate sacks, and stitched or heat-sealed heavy-duty liners.

Because collation shrink film for bottle multipacks must retain machine-direction orientation memory after storage at warehouse temperatures up to 45°C, film formulations containing 70–80 wt% FS19020 and 20–30 wt% LDPE are processed on blown film towers with high stalk heights. The stalk height is adjusted to 8–12 times the die diameter to increase melt orientation in the machine direction before bubble expansion. Die gaps are reduced to 1.2–1.6 mm to raise shear rate, and melt temperature is held between 200°C and 220°C to preserve orientation without surface melt fracture. Finished film of 35–60 µm thickness is evaluated for free shrink in hot oil under ASTM D2732; machine-direction shrinkage at 120°C should exceed 40%, while transverse-direction shrinkage is typically 8–15%. Shrink force measured on a universal testing machine at 120°C remains below 2.5 N/15 mm to prevent deformation of thin-wall PET bottles during tunnel residence at 150–165°C. Because collation shrink is secondary packaging, direct food-contact migration testing is not triggered; European supply chain documentation under REACH 1907/2006 remains applicable. Terminal products include printed multipack films for 300 mL and 500 mL bottles, overwrap for canned goods trays, and registered shrink films for club-store bundles.

What Changes When FS19020 Replaces Conventional LDPE Sealant in Extrusion Lamination?

In extrusion lamination of reverse-printed BOPP and polyester webs, FS19020 is melt-extruded as the sealant web at thicknesses from 18 µm to 30 µm. The resin is run at melt temperatures of 280–300°C when used as the extrusion coat over aluminium foil or metallized film, because higher melt temperature reduces viscosity and promotes the oxidation required for adhesion to substrates pre-treated to dyne levels above 38 mN/m. A typical extrusion coating structure is 12 µm polyester film / 10–12 g/m² LDPE tie layer / 7 µm aluminium foil / 20–25 µm FS19020 sealant web. Adhesion of the sealant web to foil is tested by peel strength under ASTM F904; values above 3.0 N/15 mm are expected after 24 h conditioning. Heat seal strength is measured under ASTM F88 with 1.0 s dwell time at 110–130°C and 0.275 MPa jaw pressure; target seal initiation temperature is below 105°C. Hot tack is measured under ASTM F1921 for vertical form-fill-seal packaging, where the seal must hold immediately after jaw release before the filled product creates a peeling force. Food-contact use of the sealant web requires verification under FDA 21 CFR 177.1520 for U.S. conditions of use and global migration testing under Regulation (EU) 10/2011 using food simulant A, B, and D2 when sold into European supply chains. Terminal products include liquid soap sachet laminates, coffee bag inner liners, and retortable pouch sealant layers where exterior layers are polyester or nylon.

When Condensation Control and Light Transmission Must Coexist in Multi-Layer Agricultural Structures

Three-layer greenhouse covering films utilizing FS19020 in the core layer are produced on blown film dies with 3 extruders and layer distribution 10–20% outer / 60–75% core / 15–20% inner. The outer layer receives 1.5–2.5 wt% hindered amine light stabilizers, the inner layer receives 0.8–1.5 wt% anti-fog additive masterbatch, and the core contains FS19020 as the mechanical integrity layer. Density in the 0.918–0.922 g/cm³ range provides the low crystallinity needed to accept stretching during installation on arched tunnels without stress whitening at fold points. Mechanical properties after 12 months of field exposure in a Mediterranean climate are specified by tensile strength retention above 70% under EN ISO 527-3 and elongation retention above 60% in the transverse direction. Haze after anti-fog conditioning is measured by ISO 14782; values above 15% trigger evaluation of layer uniformity and additive dispersion. Finished agricultural films may be assessed under EN 13206 for covering films used in agriculture and horticulture; REACH registration under 1907/2006 is required for the resin and stabilizer additives in European distribution. Terminal products include 180 µm and 200 µm greenhouse covers, low-tunnel mulch replacement films, and side-roll ventilation curtains.

Under direct food-contact regulation in the United States, FS19020 may be used as the sole food-contact layer when the finished film meets the extractives limits of FDA 21 CFR 177.1520 for olefin polymers. The resin is converted on cast film lines at 15–25 µm thickness for bakery overwrap and produce bags. Antiblock masterbatch loading in this application is held to 0.2–0.5 wt% synthetic silica to avoid lowering clarity; slip additive at 300–800 ppm erucamide is added when machinability on horizontal form-fill-seal lines requires coefficient of friction below 0.30 under ASTM D1894. Heat seal jaws on vertical form-fill-seal equipment operate at 105–125°C with 0.3–0.5 s dwell time; seal strength under ASTM F88 exceeds 4 N/25 mm on 20 µm film. Migration testing follows Regulation (EU) 10/2011 Annex III food simulant A for aqueous foods and simulant D2 for fatty foods when the film is sold into European supply chains. Printing is applied to the outer surface only, and solvent retention is controlled by the converter under the packaging standard applicable to the final filled product. Terminal products include bread bags, croissant sleeves, and fruit bunch bags with water-based ink on the outer surface only.