In coextruded flexible packaging converting, the sealant web is processed on a three-layer blown-film line with a 30:1 L/D barrier screw, a 1.6 mm die gap, and an external surface gauge control loop. Dow ATTANE VLDPE 4402, an ethylene-octene copolymer with a nominal density of 0.902 g/cm³ and a melt index of 0.8 g/10 min under ASTM D1238 at 190°C/2.16 kg, is introduced as the inner sealant layer at thicknesses from 15 μm to 25 μm. The sealant-layer formulation for a stand-up pouch web typically consists of 80 wt% ATTANE 4402, 18 wt% of a 0.5-MI LLDPE added for bubble stiffness and tack reduction, and 2 wt% of a 5 wt% silica antiblock masterbatch. Melt temperature is maintained at 220–235°C, and the die pressure is monitored to avoid excursions above 28 MPa. The bubble is run at a blow-up ratio of 2.2:1 to 2.8:1, and the frost line height is held between 350 mm and 500 mm above the die face to balance transverse orientation and heat seal stability. In this configuration, the heat seal onset, defined as the jaw temperature at which peel force reaches 3.0 N/15 mm under ASTM F88 with 200 mm/min jaw separation, is reached at a lower set point than for conventional LDPE-rich sealants; the precise offset depends on seal dwell time and is established on the converting line rather than inferred from resin data. Hot tack force is measured under ASTM F1921 at 0.5 s seal dwell and 0.25 s cooling delay. For food-contact laminates, the resin complies with FDA 21 CFR 177.1520(c) paragraphs 3.1a and 3.2a as an olefin polymer, and under EU Regulation (EU) No 10/2011 the final formulation must satisfy an overall migration limit of 10 mg/dm² using the appropriate food simulant in EN 1186-1 migration testing. The terminal structures are used in dry-mix pouches, liquid detergent flexible packs, and gusseted side web for stand-up packaging lines.

Can VLDPE 4402 Replace EVA in Frozen-Food Laminate Sealants Without Cold-Temperature Impact Loss?

Replacement of ethylene-vinyl acetate sealant layers in frozen-food laminates is evaluated when cold-temperature tear resistance and low odor are processing priorities. A monolayer or three-layer freezer film is produced at 50–75 μm gauge with a sealant blend of 70 wt% ATTANE 4402 and 30 wt% of a 1.0-MI C8 metallocene LLDPE. The blown-film line is equipped with internal bubble cooling, a dual-lip air ring, and segmental gauge control; melt temperature is held at 215–235°C, the blow-up ratio is set at 2.5:1, and chilled process air at 10–15°C is delivered to the bubble. The film is tested for dart impact per ASTM D1709, Elmendorf tear per ASTM D1922, and seal strength per ASTM F88 over a jaw temperature ladder from 105°C to 125°C. The substitution of EVA by ATTANE 4402 eliminates acetic acid odor during extrusion and reduces die-lip deposit, but the low-density film may exhibit higher blocking tendency unless the formulation contains 0.08–0.12 wt% erucamide as a migratory slip additive. Cold-temperature flexural cracking is assessed by tumbling filled pouches at -30°C for 8 h, a production line test that is correlated with ASTM F392 but is not a substitute for standardized flex-crack evaluation. For food-contact compliance, the finished structure is tested under FDA 21 CFR 177.1520 and EU Regulation (EU) No 10/2011; because the application is frozen filling and storage, migration testing with simulant A at 40°C for 10 days is commonly selected. Terminal articles include pillow pouches, gusseted freezer bags, and leak-resistant carton liners for vegetables and seafood.

Flex-Crack Resistance in Bag-in-Box and Edible-Oil Liner Constructions

In high-speed bag-in-box liner production, 80–120 μm cast film for wine, dairy, and edible-oil packaging uses ATTANE 4402 as the sealing and flex-crack-resistant inner layer because the low modulus of the resin reduces pinhole initiation under repeated mechanical flexing. The two-layer cast structure contains 70–85 wt% ATTANE 4402 in the inner layer and 15–30 wt% of a 1.0-MI LLDPE in the outer layer for roll release and thermal stability. Extrusion is performed on a 75 mm cast-film unit with a 30:1 L/D screw, die gap 0.7 mm, melt temperature 245–260°C, and chill roll temperature 18–22°C; the air gap from die to nip is set between 100 mm and 150 mm to reduce neck-in. The inner layer thickness is 25–40 μm within the overall gauge. Flex-crack resistance is measured under ASTM F392 using 5,000 Gelbo flex cycles, with pinholes counted by dye penetration; a line-specific pinhole acceptance limit is established because published data for this exact structure is limited. Seal strength is measured under ASTM F88, and the required seal threshold for liquid containment is set by burst testing under ASTM F1140 or an equivalent internal pressurization method. Food-contact compliance requires testing under FDA 21 CFR 177.1520 and EU Regulation (EU) No 10/2011; edible-oil applications are tested with simulant D2 at 40°C for 10 days, and high-acid liquids are tested with simulant C. The terminal products are 5-L to 220-L bag-in-box liners, liquid concentrate bags, and foodservice syrup bladders.

A three-layer heavy-duty sack line running 100–150 μm gauge film for polymer resin and construction aggregate packaging uses ATTANE 4402 because the resin increases dart impact and puncture energy while retaining processability at moderate backpressure. The film structure comprises 80 wt% ATTANE 4402 in the core and inner layers, 20 wt% high-pressure LDPE in the outer layer, and an added 4 wt% carbon-black masterbatch for UV screening. The blown-film extruder is configured with a 90 mm single screw at 30:1 L/D, a 400 mm die, die gap 1.8 mm, and a blow-up ratio of 2.0:1 to 2.4:1. Melt temperature is held at 210–230°C; screw speed is normally limited to 90 rpm or below because the 0.8-g/10-min melt index of 4402 raises melt temperature and can initiate local gel formation under high shear. Puncture resistance is measured under ASTM D5748, Elmendorf tear under ASTM D1922, and tensile break under ASTM D882. A minimum gauge threshold of 100 μm is imposed for rough aggregate handling because the low flexural modulus of 4402 reduces film rigidity; below that gauge, the sack may fold excessively during automatic filling. Industrial packaging in the European Union is checked against REACH SVHC limits of 0.1 wt%, and the film is not intended for direct food contact unless a separate food-grade liner is used. Terminal articles include FIBC form-fit liners, valve sacks for polymer pellets, and rubble chute drop skins.

Adding 4402 to Collation Shrink Blends Depresses Seal Initiation But Also Modifies Transverse Shrink Force

For collation shrink films serving 12-pack and 24-pack bottle formats, the inclusion of ATTANE 4402 lowers seal jaw set points by 10–15°C, but the same addition level reduces transverse shrink tension compared with neat LDPE. A starting formulation is 20 wt% ATTANE 4402, 75 wt% of a 0.3-MI LDPE, and 5 wt% of a slip/antiblock masterbatch. The high-stalk blown-film line uses a 350 mm spiral mandrel die, die gap 1.2 mm, blow-up ratio 4.0:1 to 5.0:1, and frost line height 900–1,100 mm to lock in transverse orientation. Melt temperature is set at 200–215°C. Unrestrained linear shrinkage is measured under ASTM D2732 at 110°C and 120°C in both machine and transverse directions, and shrink force is measured on a dedicated strain-gauge analyzer at 1 s contact time. Because the ULDPE phase softens the orientation stress, the transverse shrink force at tunnel temperatures between 160°C and 180°C must be confirmed on the line; published data for this specific blend is limited. If the measured shrink force falls below the pre-established line minimum, the LDPE fraction is increased or the blow-up ratio is raised toward 5.0:1. Seal strength is checked at 180°C and 0.3 s jaw dwell using ASTM F88. Consumer packaging compliance falls under EU Directive 94/62/EC for packaging and REACH; direct food contact is not claimed. Terminal products include shrink bundles for PET bottles, metal can six-packs, and industrial spare parts overwrap.

When Cast-Film Surface Protection Requires Low-Modulus Conformability Without Tackifier Migration

When cast-film surface protection is produced for polycarbonate sheet, stainless steel coil, and pre-painted aluminum panels, the film must conform to surface irregularities without edge lift and must release cleanly. ATTANE 4402 is used as the skin layer in a two-layer cast film at 20–35 μm overall thickness, with a formulation of 85 wt% ATTANE 4402 and 15 wt% of a 0.5-MI metallocene LLDPE for slip and stiffness. The cast line uses a 65 mm extruder at 28:1 L/D, die gap 0.6 mm, melt temperature 235–250°C, and a polished chill roll at 25°C. The die-to-roll air gap is set between 50 mm and 70 mm to limit oxidation and maintain surface uniformity. Corona treatment is set to 38–42 dyn/cm per ASTM D2578, and peel adhesion is measured under ASTM D3330 at 180° and 300 mm/min. The low modulus of 4402 reduces stress whitening at stretched edges compared with LLDPE, but skin-layer addition above 90 wt% can cause roll blocking; therefore an antiblock masterbatch is added at 0.5–1.0 wt% and winding tension is limited to 15 N/250 mm. The product is outside direct food contact; compliance is governed by RoHS Directive 2011/65/EU and REACH. Terminal applications include protective surfacing for architectural panels, automotive body panels during transit, and laser-cut metal sheets.

Paperboard extrusion coating with VLDPE 4402 at addition levels above 15 wt% is constrained by the resin melt index of 0.8 g/10 min, which raises backpressure and reduces maximum line speed on a conventional 30:1 L/D extruder. In practice, the resin is used as a minor toughness modifier at 10–15 wt% in a high-pressure LDPE coating resin, not as the sole coating polymer. The coating line is operated at melt temperature 280–300°C, die width 1,800 mm, and air gap 150 mm; the blend is coated at 15–20 g/m² onto barrier paperboard. The low density of 4402 increases edge adhesion on difficult paperboard blanks, but draw resonance appears when the addition exceeds 20 wt%. Online thickness variation across the web is monitored, with a control limit of ±2.0 μm; when the limit is exceeded, the LDPE fraction is increased. Peel adhesion to paperboard is tested under ASTM D1876 or TAPPI T 540. Food-contact board requires compliance with FDA 21 CFR 176.170(c) for paper and paperboard components and EU Regulation (EU) No 10/2011 for the plastic coating layer. Terminal products include frozen-food folding cartons and aseptic brick overcoating for dry products.