A 3-layer blown film line operating with a 200 mm annular die, 1.2 mm die gap, and 1.8:1 to 2.5:1 blow-up ratio can position ATTANE 4403 as the sealant skin adjacent to a core of C4-LLDPE and an outer layer of HDPE. The heat seal initiation window in the sealant layer is controlled by the 1-octene comonomer content, which lowers the crystalline melting point below that of conventional LLDPE. The resin is supplied with a nominal density of 0.903 g/cm³ by ASTM D792 and a melt flow rate below 1.0 g/10 min by ASTM D1238 at 190 °C and 2.16 kg. In production trials, the sealant skin typically makes up 15–25 wt% of total film structure, with ATTANE 4403 comprising 75–90 wt% of that skin and the balance being LDPE or a slip-antiblock masterbatch. The LDPE addition reduces blocking during rewind at film temperatures above 35 °C, while addition rates above 20 wt% LDPE raise the minimum seal bar temperature by 3–6 °C. A typical dry-blend formulation for a 20 μm sealant skin is 80 wt% ATTANE 4403, 17 wt% LDPE with density 0.923 g/cm³, and 3 wt% of a masterbatch containing 5% erucamide and 15% synthetic silica. For high hot-tack snack packaging, the LDPE is partially replaced by a tie-layer-grade ethylene-acrylate copolymer at 5–10 wt% to widen the seal plateau. The extruder profile for the sealant skin is 180–210 °C in the feed zone, 200–225 °C in the compression zone, and 215–230 °C at the adapter, with die temperature held at 220–235 °C. Frost line height is maintained at 4–6 die diameters for blown films, because higher frost line height worsens tack and blocks the film on the collapsing frame. Corona treatment of the sealant surface at 38–42 dyn/cm improves lamination bond but must be delayed until immediately before lamination to avoid surface oxidation. Compliance for the final food-contact structure rests on supplier documentation for FDA 21 CFR 177.1520 olefin polymer provisions and EU Regulation No 10/2011, with overall migration testing to EN 1186-1:2002 when the sealant layer directly contacts fatty foods. Table 1 summarizes the compliance anchors. Terminal structures include frozen food bags, dry snack pouches, cereal liners, and barrier laminates for coffee.

When Cast Film Pre-Stretch Exceeds 220% on a 7-Layer Pallet Wrap Line

Higher pre-stretch ratios on a 7-layer cast film line require a skin layer that can survive intensive elongational flow without puncturing at core layer instability. ATTANE 4403 is introduced into the cling and outer skin layers at 55–75 wt% of those layers, with the remaining portion being metallocene LLDPE and 2–4 wt% of a polyisobutylene-based cling additive. The core layers contain C6-LLDPE or C8-LLDPE for stiffness. Die temperature is set to 235–245 °C, and the chill roll is kept at 15–20 °C. Melt temperature is held below 250 °C to avoid degradation of the erucamide and PIB cling agents. The resin’s low density of 0.903 g/cm³ by ASTM D792 reduces the secant modulus of the stretched film, allowing pre-stretch ratios up to 250% on modern pre-stretch heads. Cling performance is tested by ASTM D5458 peel cling; a loss of cling below 80 g/25 mm after 30 days indicates migration of the cling additive into the core or excessive surface oxidation. For machine film at 23 μm, edge encapsulation with a stiffer LLDPE reduces neck-in to 40–60 mm per die edge. Terminal products include machine-applied pallet wrap, hand stretch wrap, and protective wrapping for industrial parts. The principal processing boundary is line speed: at speeds above 700 m/min, melt resonance may appear unless the die gap is reduced to 0.5 mm and the air knife temperature is raised to 50 °C. The cling layer should not be corona-treated, because surface oxidation destroys tack. The reel-wound film is conditioned at 20–25 °C for 24 h before slitting to prevent gauge bands.

Extrusion laminators running 90–120 m/min on a tandem line with a 1,200 mm slot die can deposit a 12–18 μm layer of ATTANE 4403 between aluminium foil and a PET print web. In this structure, ATTANE 4403 functions as a low-temperature sealing layer and as a stress-coupling layer. The melt temperature at the die is set to 230–245 °C, and the molten curtain is pinned to the foil by a chill roll at 12–18 °C. Ozone treatment at 40–60 g/m³ is applied to the melt surface just before the nip to increase adhesion to the oxidised aluminium surface. Without ozone, peel adhesion measured by ASTM D1876 drops below 4 N/15 mm on unprimed foil. The sealing layer is usually a blend of 85–95 wt% ATTANE 4403 and 5–15 wt% LDPE to reduce draw instability. The LDPE addition raises the seal initiation temperature slightly, but improves flow through the coat-hanger die. The inner sealant layer is subjected to a maximum package seal temperature of 130 °C, because above that the layer begins to extrude from the seal area. The final laminate is used for stand-up pouches, sachet stock, and lidding film for semi-solid foods. Compliance for the food-contact side is supported by FDA 21 CFR 177.1520 supplier documentation, with migration testing to EN 1186-1:2002 for fatty food simulants. The limiting operational condition is moisture on the aluminium foil: moisture at the nip produces pinholes and lowers bond strength, so the foil web is preheated to 40–50 °C.

What Limits Single-Screw Output in Flexible Tube Extrusion?

The dominant constraint in mono-layer tube extrusion from ATTANE 4403 is the melt fracture threshold of the resin at high shear rates. A 60 mm single-screw extruder with 24:1 L/D and a barrier screw is operated with a temperature profile of 170–190 °C in the feed zone, 190–215 °C in the metering zone, and 215–225 °C at the tubular die. Tube wall thickness is typically 1.0–2.5 mm. ATTANE 4403 is blended with 10–30 wt% LDPE to reduce die build-up, because the octene-rich resin alone can generate polymer deposits on the mandrel after six hours of continuous running. For flexible beverage dispensing tubes and protective sleeves, the formulation often includes 0.1–0.3 wt% erucamide and 0.5–1.0 wt% hindered amine light stabilizer when the tube is exposed to sunlight. The kink resistance is determined by measuring the ratio of tube lumen collapse under 50% lateral deflection; the low crystallinity of ATTANE 4403 assists but does not remove the need for a 5–10 wt% EVA addition in tight-bend applications. Extrudate surface becomes rough when the apparent wall shear rate exceeds 1,000 s^-1 on this line, at which point the head pressure must be reduced by increasing the die temperature to 225 °C and lowering screw speed. No pre-drying is required if the resin is kept sealed at warehouse relative humidity below 60% for less than six months. The terminal products made from such tube stock include peristaltic pump tubing, beverage plumbing, and cable protection sleeves where UL flame ratings are not required.

Air Cushioning Film Collapse Pressure and Octene Content

Air cushioning films produced from ATTANE 4403 are sealed on a rotary heat-sealing drum after tubular blown film extrusion. The film is blown at a blow-up ratio of 2.0:1 to 2.5:1 and at a die temperature of 210–225 °C. The resin is normally blended with 20–40 wt% C8-LLDPE to raise the modulus of the inflated cells after sealing. The cell collapse pressure is measured by applying an increasing load to a film sample until 50% of the inflated cells fail; structures based on ATTANE 4403 show lower collapse pressure than HDPE-based cushioning but higher puncture tolerance by ASTM D5748. The seal layer must be kept free of slip additives above 0.2 wt%, because excessive erucamide interferes with the heat-seal on the rotary drum. The melt temperature is held at 220–235 °C; lower temperatures create incomplete cell sealing at line speeds above 80 m/min. Pre-drying at 70 °C for 4 h is recommended if the resin is exposed to relative humidity above 60% for more than 48 h, because surface moisture creates steam bubbles at the die. Terminal products include protective void-fill pillows, furniture edge protectors, and light-cushion mailer liners. The main limitation is storage under sustained pressure: continuous loading above 2 bar internal cell pressure will creep and thin the cell walls faster than an HDPE-based structure.