Dow ELITE AT mLLDPE AT 6111 is characterized by a nominal melt index of 1.0 g/10 min (ASTM D1238, 190°C, 2.16 kg) and a nominal density of 0.912 g/cm³ (ASTM D792). In three-layer coextruded sealant webs for frozen produce, AT 6111 is compounded into the inner heat-seal layer at 70-80 wt% with 20-30 wt% fractional-melt LDPE having a melt index of 0.25-0.5 g/10 min. On a 3-layer blown film line with 60 mm/75 mm/60 mm extruders and a 250 mm spiral mandrel die, the die gap is maintained at 1.6-1.8 mm, blow-up ratio at 2.2:1-2.8:1, and frost line height at 300-450 mm from the die face. The sealant layer is targeted at 12-18 µm inside a finished film of 50-70 µm. Erucamide slip concentrate is metered into the sealant layer at 800-1200 ppm and synthetic silica antiblock at 2000-3000 ppm. The melt is filtered through 40/60 mesh screen packs to reduce gel transmission. The principal process constraint is backpressure: an AT 6111-rich sealant layer can generate 15-25% higher screw backpressure than a conventional C8-LLDPE sealant blend at the same throughput, and lower-shear barrier screws with no Maddock mixing elements are specified to keep melt temperature below 225°C. If the die gap is widened beyond 2.2 mm to lower backpressure, orientation relaxation becomes measurable and dart impact measured by ASTM D1709 Method A may fall below the 400 g lower control limit commonly set for 60 µm frozen vegetable bags. Heat-seal strength is tested per ASTM F88/F88M; commercial lower control limits for 60 µm sealant film are typically 8-12 N/25 mm after 0.5 s dwell at 150°C. Hot tack is evaluated per ASTM F1921 with 0.5 N seal force and 0.5 s dwell; a force below 2 N/25 mm at 0.2 s delay is interpreted as a seal initiation failure on vertical form-fill-seal lines running above 70 pouches/min. Surface coefficient of friction is tested per ASTM D1894, with a kinetic COF of 0.15-0.30 typically specified for automated bagging lines. Optical haze is measured per ASTM D1003; a specification of 8-12% for 60 µm film is common for retail frozen produce packaging. The sealant layer is tested for food-contact compliance under FDA 21 CFR 177.1520(c) and EU 10/2011. Overall migration is controlled to ≤10 mg/dm² using 95% ethanol and 3% acetic acid food simulants as specified in the relevant test condition. Terminal packaging includes frozen broccoli and spinach pillow pouches, frozen seafood bags, and cereal liners.

What Changes When AT 6111 Replaces 30% of HDPE in a Heavy-Duty Sack Skin Layer?

On high-output three-layer blown film lines with 70 mm/90 mm/70 mm extruders, 30:1 L/D screws, and a 300 mm spiral mandrel die, heavy-duty industrial sacks are run at film thicknesses of 100-180 µm. The formulation uses 75-80 wt% AT 6111, 20-25 wt% HDPE, and up to 5 wt% carbon black masterbatch. Replacing 30 wt% of HDPE in the skin layer with AT 6111 lowers film density and raises puncture resistance, but the bubble becomes more prone to creep instability at line speeds below 25 kg/h. Die pressure increases by approximately 10-15% relative to an HDPE-rich structure, and the blow-up ratio is reduced from 3.0:1 for HDPE-rich structures to 2.2:1 to keep the frost line below 500 mm. Dart impact per ASTM D1709 Method A is applied to 125 µm film; converter lower control limits are often set at 500 g, and rolls with values below 400 g are quarantined. Machine-direction Elmendorf tear per ASTM D1922 generally shows a 20-30% improvement relative to HDPE-rich structures, but cross-direction tear can decrease when blow-up ratio falls below 2.0:1. Heat seals are produced on hot-air or impulse sealers at 160-185°C jaw temperature and 1.0-1.5 s dwell. Seal strength per ASTM F88 is specified at ≥15 N/25 mm for 150 µm sacks used for 25 kg fills. Printability requires corona treatment to ≥38 mN/m at 0.8-1.2 kW/m²·min. The main process failure mode is edge fold-over during collapsing when the blow-up ratio is too low; this produces gauge bands at the gusset folds and reduces drop impact. Terminal products include 25 kg polymer resin sacks, mineral filler bags, and FIBC inner liners.

The compliance checklist below applies to film structures entering regulated industrial and food-contact packaging markets.

Cast stretch film lines running at 450-600 m/min impose a narrow rheological window. In five-layer cast stretch systems with a 2.2 m feedblock die, AT 6111 is introduced into the core layer at 40-50 wt% with C8- or C4-LLDPE in the skin layers. The melt temperature at the die is held at 235-250°C; the chill roll setpoint is 18-25°C. Film gauges are 10-23 µm. The formulation targets high puncture resistance in the 150-250% prestretch range. Puncture resistance is tested per ASTM D5748; a lower control limit of 25 N at 23 µm is common for machine film. Cling layers use 1-3 wt% polyisobutylene tackifier in the skin layer only, not in the AT 6111 core layer. The process risk is neck-in at the die gap: melt-web neck-in above 25% produces edge bead thickness variation greater than ±2 µm and downstream roll telescoping. AT 6111 reduces draw resonance relative to conventional LLDPE but increases extruder motor load; barrel temperature zones 2-4 are typically increased by 5-10°C to control backpressure. Moisture in colorized regrind above 0.1 wt% can generate surface splay in cast film, so regrind is limited to 20 wt% and pre-dried when ambient relative humidity exceeds 60%. Published data for this specific resin configuration in cast stretch film is limited; the process values above are production-window observations rather than datasheet film properties. The finished films serve as 23 µm machine-grade stretch wrap and 17 µm manual hand wrap.

If Silage Wrap Is Exposed to 250 kLy of UV Radiation Without Stabilizer Masterbatch, Premature Embrittlement Occurs

Agricultural silage wrap based on AT 6111 requires 12-15 wt% HALS/UV absorber masterbatch and 5 wt% blown-film processing aid, is blown at 200-240 µm with a blow-up ratio of 2.5:1, and is tested for tensile elongation retention after 3,000 h of ISO 4892-2 exposure, because the as-supplied grade contains no UV stabilization package and will otherwise lose more than 50% of original elongation during a single silage season; the same blown-film line should not process the UV masterbatch with an amide-based processing aid above 500 ppm due to additive migration that reduces interlayer adhesion.

Extrusion Lamination Sealant Webs on Chill-Roll Lines

In duplex and triplex flexible packaging laminates, AT 6111 is applied in the sealant or lamination layer on a tandem extrusion coating line equipped with a 90 mm extruder, 30:1 L/D screw, 1.2 m slot die, and a chill roll maintained at 15°C. The melt temperature is set at 260-290°C, and the air gap is 150-220 mm. When laminating to aluminum foil or PET, an adhesion promoter or tie layer is required; oxidized polymer is deposited directly in the first pass. The typical coat weight is 18-30 g/m² at line speeds of 80-150 m/min. The process is constrained by melt curtain stability: if the melt web tears at speeds above 130 m/min, reducing the melt temperature by 10°C stabilizes the curtain through increased melt strength but elevates neck-in. Neck-in greater than 20% per edge causes non-uniform coat weight and edge trim scrap above 12%. Where paperboard is the primary substrate, corona treatment is raised to ≥40 mN/m before extrusion, and moisture content in the board is maintained below 6 wt% to prevent fiber tear and steam blisters. The laminated sealant layer is evaluated for bond strength per ASTM D1876 and heat-seal strength per ASTM F88. Converter specifications for dry food laminates often require a minimum seal strength of 8 N/15 mm at 160°C jaw temperature and 0.5 s dwell. For food-contact laminates, the finished structure is tested under EU 10/2011 with an overall migration limit of 10 mg/dm² after 10 days at 40°C. End products include dry soup packet laminates, coffee pouch films, and snack bag structures.

Hot-Tack Decay Is Measured Under Low Seal Force on Single-Station Pouch Lines

Single-station pouch lines that seal at 60-80 pouches/min place the seal bar force between 1.0 kN and 2.0 kN per meter of seal width. The hot-tack performance of AT 6111 is evaluated by ASTM F1921 with 0.5 N seal force and 0.5 s dwell, with delay times of 0.2 s and 0.5 s. If the hot-tack force drops below 1.5 N/25 mm at 0.5 s delay, the pouch opens during filling on single-station machines. Jaw temperature is verified with a calibrated thermocouple probe to ±2°C before each shift; the sealant layer is therefore formulated with 70 wt% AT 6111 and 30 wt% LDPE. This blend widens the sealing window but shifts the minimum sealing temperature upward by 5-10°C. Machine operators compensate by raising the seal bar temperature 10-15°C and extending dwell from 0.5 s to 0.8 s. However, when dwell exceeds 1.0 s, the outer PET layer in three-side-seal pouches can shrink and cause visual distortion. The same failure mode is observed if Teflon-coated seal bars are not replaced after visible surface wear exceeds 0.2 mm. Terminal products include single-serve condiment pouches, detergent pod overwrap, and liquid laundry packet films.