In high-output monolayer liner production on 90 mm to 120 mm grooved-feed extruders with 30:1 L/D ratios, Braskem HF0131, a butene copolymer blown film LLDPE with nominal density 0.918 g/cm³ under ASTM D1505 and nominal melt index 1.0 g/10 min under ASTM D1238 at 190 °C/2.16 kg, is blended at 60 wt% to 85 wt% with clean post-industrial LLDPE/LDPE reclaim and, where stiffness is required, 15 wt% to 30 wt% of an HDPE having nominal density between 0.945 g/cm³ and 0.955 g/cm³. The extruder temperature profile is ramped from 180 °C at the feed throat to 210 °C at the adapter and die. The annular die gap is maintained at 1.8 mm to 2.5 mm because narrower gaps at high screw speeds can amplify melt pressure behind the screen pack above 250 bar. A blow-up ratio of 2.2:1 to 3.0:1 is used, with a frost line height of 2 to 3 die diameters for balanced machine-direction and transverse-direction tear values under ASTM D1922. High stalk machines can operate toward the lower end of that range, while low stalk lines with dual-lip air rings can approach 3.0:1 if internal bubble cooling is available. The film is converted into waste collection sacks, construction debris liners, and industrial bulk packaging. For non-food industrial packaging, European Packaging Directive 94/62/EC Article 11 heavy metal limits apply, and REACH Regulation (EC) No 1907/2006 Annex XVII restricts substances in articles. Color concentrates based on carbon black at 2 wt% to 5 wt% are common for UV stability in outdoor storage, but carbon black agglomerates above 20 µm can initiate pinholes at 25 µm film thickness.

Why Silage Film Lines Run a Three-Layer Butene LLDPE Core?

Silage film converters running three-layer lines with 800 mm to 1,200 mm annular dies tend to position HF0131 in the core layer at 60 wt% to 70 wt% because the grade contributes puncture resistance during high-density bale wrapping without raising melt pressure excessively. The outer white layer is usually 15 wt% to 20 wt% of LLDPE or LDPE containing titanium dioxide at 6 wt% to 10 wt%, a hindered amine light stabilizer package at 0.2 wt% to 0.5 wt%, and a UV absorber at 0.1 wt% to 0.3 wt%. The inner cling layer is often 10 wt% to 15 wt% of EVA with vinyl acetate content between 9 wt% and 14 wt% plus polyisobutylene cling additive. The melt temperature at the die is held between 190 °C and 220 °C, and the blow-up ratio is increased to 2.8:1 to 3.2:1 to balance tear resistance. The frost line is raised to 4 to 6 die diameters to reduce transverse-direction orientation and improve tear propagation resistance under ISO 6383-2. Process conflict arises because excessive frost line height above 6 die diameters can induce bubble back and increase gauge variation beyond ±8% at 1,200 mm die widths. EN 13207 specifies mechanical properties for thermoplastic silage films; converters should verify that the final three-layer film meets the tensile and tear requirements of EN 13207 before use. The end products are round bale wrap, silo cover, and temporary greenhouse film.

At film conversion temperatures below -20 °C, the ductile-to-brittle transition of a butene LLDPE sealant layer becomes the controlling variable for frozen food package integrity. In three-layer coextruded structures, HF0131 is typically compounded in the sealant layer at 70 wt% to 80 wt%, with a metallocene plastomer or low-density polyethylene at 20 wt% to 30 wt% to lower seal initiation temperature. The outer layer is usually high-density polyethylene or a stiffer LLDPE for surface hardness and moisture vapor transmission control. The die gap is held between 1.6 mm and 2.0 mm, and the blow-up ratio is kept at 2.0:1 to 2.5:1 to preserve machine-direction strength. Heat-seal dwell time is set between 0.3 s and 0.8 s at seal bar temperatures from 105 °C to 130 °C, with hot tack force measured according to ASTM F1921. The film must comply with FDA 21 CFR 177.1520 for olefin polymers and with European Regulation (EU) No 10/2011 Annex I and Annex II for food contact materials. Specific migration of constituents must be verified under the intended time and temperature conditions of frozen storage. Films are converted into pillow bags for IQF vegetables, poultry overwrap, and barrier-free frozen seafood pouches. Published data for this specific HF0131 formulation under commercial deep-freeze distribution is limited; converter trials are required to establish dart impact and tear values on the target line.

When Form-Fill-Seal Sealant Layers Require a 1.0 g/10 min Melt Index

Vertical form-fill-seal operations converting granular dry mixes place simultaneous demands on sealant layer hot tack, bubble stability, and roll unwind tension. HF0131 is introduced into the sealant layer at 20 wt% to 40 wt% of the total film structure, with a metallocene LLDPE or LDPE to shift seal initiation below 110 °C. The outer layer contains HDPE at 30 wt% to 50 wt% of the total structure for stiffness and moisture resistance. The core layer may contain the remaining LLDPE plus process regrind. A three-layer blown film die with gap 1.5 mm to 2.0 mm and a low blow-up ratio of 1.8:1 to 2.3:1 is used to increase machine-direction orientation and reduce gauge variation before bagmaking. The frost line is maintained at 3 to 5 die diameters to avoid low hot tack in the sealant. Hot tack strength is measured with ASTM F1921, and seal initiation is determined with a gradient heat sealer at 0.5 s dwell time and 0.3 N/mm² seal pressure. For food contact, the sealant layer must meet FDA 21 CFR 177.1520 and European Regulation (EU) No 10/2011, including overall migration below 10 mg/dm² under simulated dry food conditions. End products include pillow pouches for rice, dry pet food bags, and sealed pouches for powdered drink mixes.

Collation Stretch Film: Die Gap, Blow-Up Ratio, and Low-Temperature Puncture

On blown stretch-film lines with 50 mm to 75 mm grooved-feed extruders, HF0131 is processed at melt temperatures of 195 °C to 225 °C and die gaps of 1.8 mm to 2.5 mm. The blow-up ratio is set between 2.5:1 and 3.5:1 to generate balanced stretch force in both directions; internal bubble cooling is normally required above 3.0:1 to maintain bubble stability. A polyisobutylene tackifier is added at 1 wt% to 3 wt% for cling in pallet unitization, while a slip agent may be omitted to avoid loss of peel force. The film gauge is typically 17 µm to 35 µm, and puncture resistance is measured according to ASTM D5748 or ISO 7765-2. Low-temperature performance is checked at -10 °C because cold-chain pallet handling can expose the film to embrittlement risks. The films are converted on center-fold or single-wound rewinders into hand and machine pallet wrap, beverage collation film, and freezer-grade stretch wrap. For non-food industrial packaging, REACH Regulation (EC) No 1907/2006 applies to the tackifier and polymer additives, and the finished article should be evaluated for mechanical recyclability under a suitable collection stream.

Blown Film Threading on Industrial Liquid Packaging Lines

Coextruded industrial liquid packaging structures typically split HF0131 into the outer and core layers at 50 wt% to 70 wt%, with an ethylene-vinyl alcohol copolymer barrier layer at 5 wt% to 10 wt% and tie resins at 5 wt% to 10 wt%. The die gap is maintained at 1.8 mm to 2.2 mm, and the blow-up ratio is limited to 2.0:1 to 2.6:1 to reduce barrier-layer thinning during bubble inflation. Melt temperatures at the die are kept at 200 °C to 220 °C, and the EVOH layer must be processed within the supplier's specified temperature window to avoid degradation and gel formation. The resulting film is fabricated into liners for non-hazardous liquid chemicals, IBC liners, and box-in-box liquid packaging. For dangerous goods packaging, the fabricated liner must be tested under the applicable UN packaging requirements for the specific liquid class, and the outer carton must meet the corresponding freight classification.