Blown-film conversion of a 70/30 wt% dry blend of Sinopec Maoming mLLDPE F3306S and a fractional-melt LDPE carrier is carried out on a three-layer line equipped with a 55 mm barrier screw, 30:1 L/D, and a 1.8 mm die gap. The nominal melt flow rate of F3306S is 3.3 g/10 min under ISO 1133-1, and the nominal density is 0.918 g/cm³ under ISO 1183-1; these values place the grade in the low seal-initiation window while retaining sufficient melt elongation for bubble stability at a 2.5:1 blow-up ratio. The LDPE fraction, held at 25–30 wt%, reduces die pressure from approximately 280 bar to 210–240 bar at 100 kg/h output because the narrow molecular weight distribution of metallocene resin generates higher shear viscosity than conventional Ziegler-Natta LLDPE at equivalent melt index. Die lip temperature is maintained at 220°C and the adapter at 210°C; excursions above 240°C initiate surface oxidation and increase gel speck formation on the inner tube surface. The film at 120 µm total thickness is converted into side-gusseted heavy-duty sacks for 25 kg resin and chemical powder packaging. Seal integrity is measured on the form-fill-seal line with 0.5 s dwell and 0.3 MPa jaw pressure; a target seal strength of 20 N/25 mm is verified under ASTM F88/F88M. Dart drop impact resistance of the finished sack film is screened with ASTM D1709 Method A, with the 70/30 blend typically meeting the converter’s internal minimum of 800 g at 120 µm; published data for this specific configuration is limited because end-use specifications vary with sack dimensions and fill weight. Pre-drying is unnecessary when resin has been stored at RH≤60%; if surface condensation occurs, a 4 h hopper drying cycle at 80°C prevents moisture-induced bubble instability. The terminal sack is used for high-density polyethylene resin, titanium dioxide, and other free-flowing powders requiring puncture resistance and resistance to splitting along the FFS back-seam.

Does Pallet-Unitisation Stretch Film Require a 3.3 g/10 min Metallocene Fraction?

In cast stretch-film production, F3306S is fed to the core extruder of a three-layer A/B/C cast line with a 1,500 mm die and a 0.8 mm die gap; the core layer comprises 80 wt% F3306S and 20 wt% LDPE with a melt flow rate of 2.0 g/10 min. The outer slip layer contains 2 wt% silica anti-block masterbatch, while the cling layer contains 8–12 wt% of a VA-rich EVA or polyisobutylene-based cling masterbatch and is limited to 10% of total film thickness to avoid unwind force drift. The metallocene core fraction raises the machine-direction stretch capability to 180–220% pre-stretch at 400–500 m/min line speed; this is evaluated by ASTM D882 MD elongation and residual stress after 24 h relaxation. Puncture resistance of the 17 µm cast film is tested with ASTM D5748, and the critical failure mode is not film puncture but core indentation at the pallet corner; field observations on automatic rotary wrappers indicate unstable load retention when film force falls below 0.4 N at 200% pre-stretch. Melt temperature at the die is held at 245–255°C; a temperature below 240°C increases melt viscosity to the point that die-lip build-up accelerates, while a temperature above 260°C degrades the cling additive and shifts cling force outside the 0.5–0.9 N/50 mm range measured by ASTM D5458. The terminal roll product is used for pallet unitisation of corrugated boxes, glass containers, and white goods; converters monitor roll telescoping under ISO 527-3 tensile hysteresis and limit warehouse storage to 25–35°C to preserve cling-layer migration equilibrium. Because the film is non-food packaging, compliance is limited to REACH Article 33 SVHC declaration and heavy-metal screening under RoHS when export requires it.

In high-speed pouch converting, the sealant web is co-extruded as a 30 µm layer and then extrusion-laminated or adhesive-laminated against a printed BOPET or BOPP substrate. The resin layer is blended at 80/20 wt% with LDPE to depress heat-seal initiation from approximately 105°C to 100°C at 0.5 s dwell and 0.3 MPa jaw pressure, as measured by ASTM F1921; hot-tack strength at 110°C is maintained above 1.5 N/25 mm for vertical pouch lines operating at 60–80 pouches/min. The grade is used in the sealant layer after extraction testing under FDA 21 CFR 177.1520(c) procedures for olefin polymers; food-contact conformity is additionally supported by EU No 10/2011 and GB 4806.7-2016. The lamination structure is typically 12 µm PET / adhesive / 30 µm F3306S blend. Interlaminar bond strength after solvent-free lamination is checked at 1.5 N/15 mm using ASTM F904; values below 0.8 N/15 mm indicate that the corona-treated PET surface has dropped below 42 dyn/cm before adhesive application. The sealant layer is not suitable for retort or high-temperature pasteurisation above 85°C, because seal strength under ASTM F88 declines rapidly above 90°C and the polymer relaxes under hot-fill stress; for ambient dry foods and frozen pouches the terminal product is standard. Processing on a tandem laminator uses a 90 mm extruder with 30:1 L/D and a 1,250 mm slot die; melt temperature at the die is held at 230–240°C. High-VA EVA is avoided in the sealant layer because VA decomposition at ≥230°C releases acetic acid and corrodes die lips; this is a critical incompatibility observed on long runs.

Greenhouse Film Edge-Tear Resistance After 12-Month UV Exposure

Agricultural tunnel film is produced on a mono-layer or three-layer blown-film line with a 2,000 mm die, 2.8:1 BUR, and a 150–200 µm target thickness. The formulation combines 65 wt% F3306S with 30 wt% LDPE and 5 wt% UV stabiliser masterbatch containing hindered amine light stabilizers at 0.4 wt% active HALS in the final film; a separate nickel quencher is added at 0.05 wt% only where crop tolerance to shading permits reduced PAR transmission. The metallocene fraction improves dart impact and edge-fold crack resistance relative to conventional LLDPE, but the critical greenhouse failure is not initial puncture; it is environmental stress cracking of the folded edge after 12 months of UV and pesticide contact. The film is exposed under ISO 4892-3 Method A fluorescent UV lamps for 2,000 h; retained tensile elongation in the machine direction must stay above 400% measured by ASTM D882, and the edge-fold test is performed by folding the specimen over a 2 mm radius mandrel at −10°C before tensile loading. The terminal product is a single-season greenhouse cover and low-tunnel film for solanaceous crops; the narrow molecular weight distribution of F3306S demands that the extruder temperature profile not exceed 210°C at the die, because excessive melt temperature causes the HALS package to volatilise, reducing UV life. Process observations on a 75 mm extruder with 30:1 L/D indicate that the bubble frost line should be maintained at 4–6 die diameters above the die lip; setting the frost line lower than 3 die diameters reliably induces MD-oriented tear and reduces transverse tear resistance measured by ASTM D1938 below the converter’s predetermined minimum for tunnel film. Published data for this specific configuration is limited because film performance depends on local UV irradiance and pesticide exposure; the above parameters are process targets rather than guaranteed end-use values.

Adjacent to civil containment, flexible pond liners and temporary landfill capping are produced from a 50/50 wt% blend of F3306S and conventional LLDPE with a density of 0.920 g/cm³; the mLLDPE fraction is included specifically to raise multi-axial puncture resistance and low-temperature flexibility. The liner is extruded as 0.5–1.0 mm blown film or flat sheet on a 1,200 mm slot die, then fabricated into panels by wedge welding at 300–350°C wedge temperature. Seam peel strength is measured on welded coupons under ASTM D6392 and must remain above 80% of the parent sheet yield strength; a weld failure typically occurs when the wedge speed exceeds 2.5 m/min and the sheet surface temperature falls below 220°C at the nip. Puncture resistance of the sheet is tested with ASTM D4833 using a 7.9 mm diameter probe; the 1.0 mm flexible liner typically shows a puncture resistance in the range of 300–400 N, although published data for this specific F3306S blend configuration is limited and site-specific verification is required. The terminal product is used for irrigation ponds, anaerobic lagoon covers, and temporary capping of construction spoils; it is not specified for primary hazardous-waste landfill lining where a high-density polyethylene geomembrane with 60 mil minimum thickness and GRI-GM13 certification is required. The processing window for the blown-film variant is narrow: die temperature is held at 215°C with a tolerance of ±5°C because the mLLDPE fraction increases melt pressure, and a temperature excursion below 210°C triggers melt fracture at the die lip. Post-consumer recyclate is avoided because it widens the melt viscosity distribution and produces visible gel clusters that reduce weld quality under ASTM D6392.

When mLLDPE F3306S Is Used as a 20 wt% Impact Modifier in Blown LLDPE/LDPE Film

In downgauged film for heavy-duty mailers and industrial liners, F3306S is dry-blended at 20 wt% into a base of 60 wt% conventional LLDPE and 20 wt% LDPE on a monolayer blown-film line equipped with a 60 mm grooved-feed extruder and 30:1 L/D. The function of the metallocene fraction is to shift the dart impact failure from brittle punch-through at 20 µm to ductile extensional failure, enabling downgauging from 50 µm to 40 µm without reducing the internal 400 g dart drop requirement measured by ASTM D1709 Method A. The extruder barrel profile is set at 175°C in the feed zone and 205°C at the metering zone; die temperature is held at 210°C. Because mLLDPE F3306S has a narrow molecular weight distribution, screw amperage at 90 kg/h rises by 5–8% relative to the same output with 100% conventional LLDPE, which is an expected equipment behaviour rather than a process fault. Extruder backpressure at the die is maintained below 300 bar by the LDPE fraction; above 320 bar, gel formation at the screen pack becomes significant and requires screen changes every 4 h instead of every 8 h. The terminal product is a black or grey opaque industrial liner loaded with 2 wt% carbon black masterbatch and converted into side-seal bags with a seal strength of 15 N/25 mm under ASTM F88. The grade is not used as the sole resin in this application because pure mLLDPE F3306S at 100 wt% on the same monolayer line causes bubble edge flutter at 2.0:1 BUR and requires a wider die gap of 2.4 mm; published data for this specific configuration is limited, but converter trial records identify the 20 wt% blend as the maximum practical addition before process instability exceeds downstream quality limits.