In dry-bond lamination for non-aseptic food pouches, DuPont™ Sclairfilm® SL-3 LLDPE Film, Laminating, 76.2 µm Thickness is positioned as the inner sealant layer against reverse-printed BOPP, PET, or aluminium oxide-coated PET. The sealant side is corona-treated to 38-42 mN/m before the coating station. A solventless two-component polyurethane adhesive is metered by a five-roll gravure head at 1.8-2.5 g/m². Line speed is maintained between 150 and 250 m/min to avoid over-wetting the printed web. Nip temperature is held at 55-65 °C. The wound laminate is cured at 30-40 °C for 48-96 h. Heat-seal jaws close at 120-135 °C with dwell 0.3-0.6 s and pressure 300-400 kPa. The seal-strength threshold for 500-1000 g dry product pouches is typically set at or above 8 N/25 mm on production lines using ASTM F88/F88M-21. The film should not be used as the sole barrier for oxygen-sensitive products requiring an oxygen transmission rate below 1 cm³/(m²·day·bar); a metallized PET or aluminium foil ply is required. Indirect food contact is evaluated under FDA 21 CFR 177.1520(c) 3.1a and EU Regulation (EU) No 10/2011 Annex I. Overall migration must be ≤10 mg/dm² for simulated aqueous and fatty food contact. Residual solvent in the printed ply must be held below the packaging specification limit; a common upper control limit is 5 mg/m². If the adhesive is amine-catalyzed, relative humidity above 70% RH in the coating area can generate CO₂ bubbles. Solventless adhesive dew point is monitored at 18-22 °C. For retorting above 121 °C, an alternative high-temperature sealant layer is required. End products include frozen vegetable pouches, stand-up pouches for dry mixes, and dry powder side-gusset pouches.

What Controls Seal Integrity in ISO 11607-1 Sterile Barrier Trays?

Rigid thermoformed trays made from APET, HIPS, or PP are sealed with a multilayer lidding stock in which the film functions as the sealant layer bonded to Tyvek 1073B or medical-grade paper. The lamination step is performed on a dry-bond line using a two-component aliphatic polyurethane adhesive at 2.0-3.0 g/m². Complete adhesive conversion is verified by Fourier transform infrared absence of free isocyanate at 2270 cm⁻¹. Seal window on a rotary tray sealer is evaluated between 115 °C and 145 °C in 5 °C increments. Dwell is held at 0.8-1.2 s and pressure at 0.35-0.55 MPa. The lower limit is set by the seal initiation temperature of the LLDPE layer. The upper limit is set by the onset of tray-flange distortion and Tyvek fibre tear. In peelable configurations, seal strength per ASTM F88/F88M-21 is maintained between 1.0 N/15 mm and 3.0 N/15 mm at a 180° peel angle and 300 mm/min crosshead speed. Channel-free seals are confirmed by ASTM F1929-23 dye penetration. Any dye strike-through across the flange constitutes a reject. Sterile barrier validation follows ISO 11607-1:2019 clause 5.2. The packaged device must demonstrate seal integrity after accelerated aging at 55 °C for 60 days. Biocompatibility of the film surface is evaluated under ISO 10993-1:2018. Gamma dose mapping is required; published data for this exact configuration under gamma sterilization is limited. The acceptance matrix below is applied during installation qualification of the tray sealer.

End products include sterile barrier systems for syringes, catheters, and surgical kits. If the lidding stock is subjected to ethylene oxide sterilization, moisture pre-conditioning at 50-60% RH is required before sealing to avoid seal voids. If gamma sterilization is selected, dose mapping over 25-40 kGy must confirm no post-irradiation embrittlement of the sealant layer. The film is not a substitute for a Tyvek or paper microbial barrier ply; it provides the heat-seal function only.

For desiccated powder pharmaceutical packaging, aluminium foil sachet lamination uses the film as the heat-seal ply bonded to 20-25 µm soft-annealed foil. The foil is pre-treated with a chromium-free conversion coating. Adhesion is developed with a retortable aliphatic polyurethane adhesive at 2.5-3.2 g/m². The laminate is cured at 40-50 °C for 7-10 days. The final sachet web is slit to widths of 80-140 mm with edge tolerance ±0.5 mm. Side-seal stations on vertical form-fill-seal machines operate at 140-160 °C. The 76.2 µm layer provides the seal-strength reserve needed for fin seals running at 60-100 cycles/min. Use of amine-terminated adhesives is avoided where the drug substance is moisture-sensitive because of potential aromatic amine migration. An EVOH barrier layer may be inserted between the foil and the sealant web. Compliance for pharmaceutical primary packaging includes USP chapter 661.1 plastic materials of construction and Ph. Eur. 3.1.3 polyolefin requirements. Dimensional stability of the printed foil is checked before lamination; the foil gauge must be uniform within ±5% to prevent tunnelling at the heat-seal station. End products include unit-dose desiccant sachets, transdermal patch overwraps, and powder drug side-seal packs. The film is not intended for terminal sterilization above 105 °C in this structure.

Tube laminate web for high-strength side-seam sealing

High-strength side-seam tube stock uses the film as the innermost layer over aluminium foil or EVOH barrier. The tube body is formed from a flat laminate consisting of PE/printing/paper/PE/Al/PE, with the film serving as the 76.2 µm inner PE layer. The film is adhesive-laminated to the foil with an anhydride-grafted tie resin applied at 3.0-4.0 g/m². Hot-air side-seam welding is performed at an air temperature of 390-410 °C. The LLDPE layer must have a low gel count and consistent melt flow to prevent pinholes at the welded overlap. Tube flattening and end-sealing use jaws at 160-190 °C. The thicker sealant layer increases heat sink, so dwell time is extended by 0.2-0.4 s compared with 50 µm sealant films. Leak testing per ASTM D3078-02 is performed at 40 kPa vacuum; no bubble stream indicates side-seam integrity. Compliance with EU Regulation (EU) No 10/2011 is documented through migration testing for semi-fatty and aqueous simulants. The film alone does not provide aluminium or EVOH barrier performance. End products include abrasion-resistant toothpaste tubes, barrier tubes for industrial adhesives, and cosmetic cream tubes.

Building insulation facings require a low-permeance vapour retarder tie

On a 1,200 mm extrusion coater, a tri-directional fiberglass scrim or aluminium foil facing is bonded to the film. The laminating tie is a LDPE resin extruded at melt temperature 310-325 °C through a die gap of 0.6-0.8 mm. The air gap from die exit to nip is 150-200 mm. Line speed is 100-180 m/min. The foil or scrim side is flame-treated to 42-46 mN/m before coating. T-peel adhesion is measured by ASTM D1876-08; adhesion below 1.5 N/15 mm after 24 h is treated as a lamination defect. The 76.2 µm gauge is selected for puncture and tear resistance during crawl-space installation. Puncture resistance of the finished facing is evaluated by ASTM D751-19. The finished laminate must meet the flame-spread index and smoke-developed index specified by the applicable mechanical code under ASTM E84-23. Compliance with ASTM C1136-21 for flexible, low-permeance vapour retarders applies to the finished facing, not the film alone. Avoid amine-based inks on the foil side because they can reduce interlayer adhesion after thermo-humidity aging at 90% RH and 60 °C. End products include radiant barrier facings, concrete slab vapour retarders, and pipe wrap laminates.

When closed-cell polyolefin foam cores are joined to decorative nonwoven facings

For door panel and instrument panel soft-skin laminates, the film is used as an adhesion-promoting interlayer or as a backside sealing film on polyolefin foam cores. The process uses a heated nip laminator. Nip temperature is 110-130 °C, line speed is 8-15 m/min, and nip pressure is 2.5-4.0 bar. If acoustic porosity is required, the film is micro-perforated offline on a hot-needle perforator. Hole density is adjusted between 40 and 60 holes/cm² depending on the target airflow resistance. Adhesion is measured by ASTM D1876-08 T-peel after 72 h at 23 °C and 50% RH. Flammability is tested per ISO 3795:1989; burn rate must fall below the 100 mm/min threshold prescribed by the interior material specification. Fogging is tested per ISO 6452:2021 to the OEM-specified condensate mass limit. The 76.2 µm thickness alters the thermoforming gradient relative to 50 µm interlayers, so line trials are required before full-rate production. Published data for this specific configuration is limited. End products include door panel soft inserts, console armrests, and parcel shelf coverings.