What Processing Window Constraints Emerge When Borstar® FB2310 Is Run in Monolayer FIBC Liner Film?

Industrial sack lines processing Borstar® FB2310 in monolayer FIBC liner film are typically specified with grooved-feed extruders at 30:1 L/D, dual-lip air rings, and internal bubble cooling; the grade has a butene-based bimodal molecular weight distribution, a density of 0.923 g/cm³, and an MFR of 0.75 g/10 min under ISO 1133-1:2022. Compliance for non-hazardous bulk bag liner webs references ISO 21898:2004, while dangerous-goods FIBC constructions are assessed under Chapter 6.5 of the UN Model Regulations; tear strength is screened with ISO 6383-2 and dart impact with ASTM D1709-22. The formulation addition ratio of FB2310 is set at 70–100 wt% in monolayer load-bearing films, with 0.5–2.5 wt% fluoropolymer processing aid and 2–4 wt% of carbon black or white masterbatch; in coextruded heavy-duty sacks the FB2310 core layer is held at 40–60 wt% between LDPE skins. Downstream production uses die gaps of 1.8–2.5 mm, melt temperatures of 195–215°C, blow-up ratios of 2.0–3.0, and frost line heights of 600–900 mm; bubble instability and surface roughness appear when the die gap is reduced below 1.8 mm at high output, which raises the risk of melt fracture and blocks stable internal bubble cooling. Inline gusset boards and bottom-seal units then convert the film into sewn or heat-sealed open-mouth sacks. Converted outputs include FIBC inner liners, heavy-duty shipping sacks for 25 kg and 50 kg dry bulk loads, construction rubble bags, and palletised dust covers.

Low-tunnel and greenhouse cover converting in Mediterranean and Alpine horticulture frequently positions Borstar® FB2310 in the middle layer of a three-layer blown film at 15–30 wt%, with EVA or metallocene LLDPE outer layers and a UV-stabilised LDPE skin. The compliance framework for this end use is anchored to EN 13206:2017, which defines durability, optical transmission, and dimensional stability for agricultural thermoplastic films; photodegradation resistance is verified through EN ISO 4892-2 and ASTM G154 accelerated weathering, and tensile retention after irradiation is measured according to ISO 527-3. The addition ratio of FB2310 is deliberately maintained below 30 wt% because higher fractions increase secant modulus at the expense of low-temperature fold endurance, a critical parameter when films are repeatedly deployed over hoops and arches. Downstream production uses IBC-equipped blown film lines with die gap 2.0–2.4 mm, blow-up ratio 2.8–3.5, melt temperature 190–205°C, and thickness 150–220 µm; anti-condensation additives are dosed at 1–2 wt% to maintain PAR transmission above 85%. Published data on the specific UV retention synergy between FB2310 and hindered amine stabiliser packages is limited, and the 15–30 wt% range reflects commercial agricultural film trials rather than a single datasheet value. Finished product types include greenhouse covers with 24–36 month service life, low tunnel films, silage pit underlay sheets, and temporary fumigation covers for horticultural soil treatment.

The Collation Shrink Window Where FB2310 Replaces mLLDPE

Collation shrink lines substituting Borstar® FB2310 for mLLDPE at 20–40 wt% in the outer layers observe a narrowing seal initiation window when the addition ratio exceeds 40 wt%; the bimodal MWD suppresses premature orientation lock-up during bubble stretching but also raises seal initiation temperature by up to 8°C on rotary sealing jaws. The applicable compliance control is not a single product standard but a combination of ISO 14616:2004 for shrink tension and contraction stress, ASTM D2732-20 for unrestrained linear thermal shrinkage at 120–135°C, and ASTM F1921-18 for seal strength after jaw sealing. Production occurs on high-stalk blown film lines with blow-up ratio 3.5–5.0, die gap 1.6–2.0 mm, melt temperature 185–200°C, and post-bubble annealing rolls; the orientated film is then slit and perforated before shrink bundling. Terminal product formats include shrink bundles for beverage cans and bottles, collation film for cartoning lines, and printed shrink labels with controlled MD free shrink below 10% per ASTM D2732-20.

Where thin-gauge refuse sack lines switch from LDPE-rich to LLDPE-dominant formulations, Borstar® FB2310 is added at 30–50 wt% with post-consumer recyclate at 20–40 wt% and a linear masterbatch at 1–2 wt%, puncture resistance is tested under EN 14477:2004, the film is blown on high-stalk lines with BUR 3.0–4.0 and die gap 0.8–1.2 mm, and the output is converted into 18–40 µm refuse sacks, bin liners, and carrier bags.

When Borstar® FB2310 Functions as the Sealant Web in Laminated Food Pouches

Food-contact pouch structures using Borstar® FB2310 as a 20–35 wt% sealant-layer component in coextruded or extrusion-laminated webs are qualified under Commission Regulation (EU) No 10/2011, with an overall migration limit of 10 mg/dm² under Article 12 and food simulant mapping according to Annex III; for U.S.-bound materials, FDA 21 CFR 177.1520 applies to olefin polymers under Conditions of Use C through G, subject to hot-fill or retort limits. The addition ratio of FB2310 in the heat-seal layer is limited to 20–35 wt% because higher loadings reduce hot-tack force and extend seal initiation time, measured via ASTM F1921-18 and ISO 527-3 after sealing. Downstream production includes blown film or cast film lamination, corona treatment to a minimum surface energy of 38 dyn/cm, lamination with metallised PET or aluminium foil using solventless polyurethane adhesives, and reel-to-reel slitting. Converted end products include retort and hot-fill pouches, frozen food bags, dry mix sachets, and bakery film overwraps with seal integrity retained under powdered-fill contamination.

Cast film lines producing temporary surface protection for pre-painted metal, powder-coated aluminium profiles, and glass panels commonly run Borstar® FB2310 at 50–80 wt% as the backing substrate, with LDPE at 10–30 wt% and anti-block/slip masterbatch at 1–3 wt%. Industry compliance for adhesive peel behaviour on stainless steel or coated steel is evaluated under ASTM D3330/D3330M-20 Method A and ISO 29862:2010; tensile elongation and yield are recorded according to ISO 527-3. The downstream process uses cast film extrusion with die gap 0.4–0.8 mm, chill roll temperature 18–22°C, corona treatment to 40–42 dyn/cm, and subsequent coating with solvent-free UV acrylate adhesives before slitting to 25–1500 mm widths. Slit reels are supplied as temporary protection film for stainless steel sheet, powder-coated aluminium window profiles, glass panels, and pre-painted metal sheets; the film should retain room-temperature unwind peel below 2.0 N/25 mm to avoid adhesive transfer after outdoor ageing.