Zhejiang Petrochemical mLLDPE 1018 series is a metallocene-catalysed ethylene-octene copolymer with a nominal density of 0.918 g/cm³ and a melt flow rate of 1.0 g/10 min when determined at 190 °C under a 2.16 kg load in accordance with ISO 1133-1:2022. The application records below are limited to verified blown film and cast film conversion routes in which a 0.918 g/cm³, 1.0 g/10 min octene mLLDPE is industrially specified. No injection moulding, rotational moulding, or extrusion coating sectors are included because published data for this specific series in those processes is limited.

When Seal Initiation Temperature Must Remain Below 100°C in Frozen Vegetable FFS Webs

In high-speed vertical form-fill-seal lines for quick-frozen vegetables and fruit, the sealant film is a three-layer coextruded blown web that positions mLLDPE 1018 in the inner sealant layer at 70 wt% with LDPE 2420H at 20 wt%, a silica antiblocking masterbatch at 7 wt% containing 5 wt% active synthetic silica, and an erucamide slip masterbatch at 3 wt% containing 5 wt% active slip. The LDPE fraction is retained because neat mLLDPE at 1.0 g/10 min produces lower melt tension and bubble chatter on a 250 mm die with a 2.4 mm die gap and a blow-up ratio of 2.5:1; the LDPE also widens the sealing window without eliminating the mLLDPE contribution to low seal initiation. Production on a three-layer line with internal bubble cooling, barrier screws of L/D 30:1, and melt temperatures of 195–205 °C yields a 40 µm web at 180–220 kg/h. The frost line is kept at 180–220 mm above the die face; deviation above 240 mm raises film orientation and reduces seal strength, while a frost line below 150 mm increases haze and reduces FFS tracking accuracy. Seal initiation is recorded between 95 °C and 100 °C under ASTM F2029-16 using a 0.5 s dwell and 2.0 bar jaw pressure; this allows FFS jaw temperatures of 115–130 °C to maintain throughput at 120 bags/min. A production-scale failure mode is seal contamination when active erucamide exceeds 1 500 ppm in the sealant layer because migration during film ageing shifts the coefficient of friction outside the FFS tracking window. Another observed boundary is bubble instability when ambient relative humidity exceeds 85% and cold granules carrying surface condensation enter the grooved feed throat; pre-drying is not required, but hopper temperature above dew point is necessary. Compliance for the web is tested under EU Regulation 10/2011 with the food simulants 3% acetic acid and 10% ethanol at 40 °C for 10 days, FDA 21 CFR 177.1520(c) for olefin polymers, and GB 4806.7-2016 for polyethylene food-contact materials. Terminal products are 250 g–2 kg pillow packs for frozen spinach, mixed vegetables, and blueberries distributed at −25 °C, where corner seal failure remains the primary quality complaint.

For multi-season greenhouse cover films of 150–180 µm thickness, mLLDPE 1018 is formulated at 60–70 wt% with LDPE 2420H at 15–20 wt%, a UV stabiliser masterbatch at 6–8 wt%, an anti-drip/anti-fog masterbatch at 8–12 wt%, and a polymer processing aid masterbatch at 2–4 wt%. The film is converted on a three-layer blown film line equipped with internal bubble cooling, a die gap of 2.2–2.6 mm, and a blow-up ratio of 2.0–2.2; melt temperature is held at 190–205 °C because higher temperatures accelerate HALS stabiliser degradation, while lower temperatures produce melt fracture on the outer layer. The terminal products are greenhouse covers or low tunnel films intended for 3–4 harvesting seasons in southern European, North African, and northern Chinese horticulture. The dominant field failure of greenhouse film based on low-MFR mLLDPE is not tensile yield but surface crazing and tear propagation after UV stabiliser depletion in the outer 20–30 µm layer. Accelerated weathering under ISO 4892-2:2013 with xenon arc irradiation at 0.35 W/m² and a black-standard temperature of 65 °C is used to reject stabiliser packages that fall below 50% tensile retention after 3 000 h. Compliance to agricultural film standards is verified under EN 13206:2017 and tensile properties after exposure are evaluated under ISO 527-3:2018; food-contact approval is not required, but the masterbatch carrier must comply with REACH 1907/2006 Annex XVII. A processing boundary occurs at high ambient humidity: surface condensation on granules at relative humidity above 80% introduces water into the extruder feed throat and produces bubble flash and pinholes unless hopper temperature is maintained above the dew point. Addition of anti-drip masterbatch above 12 wt% creates internal haze and reduces total light transmission; below 8 wt%, water droplets condense on the inner film surface and reduce photosynthetically active radiation transmission. Published data for this specific ZPC grade in multi-season greenhouse service is limited; the accelerated weathering threshold is therefore derived from masterbatch supplier data rather than a grade-specific field trial.

Heavy-Duty Sack Film: Melt Tension Deficits at 2.8 BUR and 1.0 g/10 min MFR

Heavy-duty open-mouth sack and FIBC liner conversion forms a three-layer blown film structure in which mLLDPE 1018 is blended at 65 wt% with LDPE 2420H at 25 wt% and HDPE 7000F at 10 wt%. The HDPE fraction raises modulus and lowers creep, but HDPE addition above 10 wt% creates a second crystalline phase with limited interfacial continuity; at 15 wt% HDPE, transverse-direction Elmendorf tear falls by 12–18% compared with the 10 wt% formulation because the HDPE lamellae orient in the machine direction and tear propagation follows the resulting crystalline boundaries. Conversion occurs on a blown film line with a 250 mm die, a 2.4 mm die gap, and a blow-up ratio of 2.2–2.8. Melt temperature is limited to 190–205 °C. At a blow-up ratio of 2.8, bubble oscillation is observed when the LDPE fraction drops below 20 wt%; the bubble edge moves ±10 mm in the transverse plane and produces gauge variation of ±6% at the winder. Substitution with high-pressure LDPE 2420H at 25 wt% restores melt tension and reduces bubble wander to ±3 mm, but raises seal initiation by 2–4 °C relative to a formulation with 20 wt% LDPE. The downstream process for FIBC liner webs often includes corona treatment to 38–42 dyn/cm before the liner is inserted into a woven polypropylene outer bag, followed by hermetic heat sealing. Terminal product types are 25 kg petrochemical and fertiliser sacks, 50 kg industrial salt sacks, and inner liners for flexible intermediate bulk containers up to 1 500 kg. Compliance for non-food chemical contact requires no food-contact approval; mechanical specifications are evaluated under ISO 527-3:2018, tear under ISO 6383-2:1983, dart impact under ASTM D1709-16a, and puncture under ASTM D5748-19.

Is the 1.0 g/10 min MFR Resin Suitable as a Cast Stretch Film Toughness Modifier?

Cast pallet stretch film presents a viscosity mismatch when mLLDPE 1018 is used as the sole resin because the 1.0 g/10 min melt flow rate increases extruder backpressure and limits thinning at line speeds above 300 m/min. The resin is instead applied as a core-layer toughness modifier at 25–30 wt% in a five-layer cast coextrusion line, combined with 55–65 wt% high-MFR mLLDPE of 3.0–4.0 g/10 min and 10–15 wt% LDPE. The die width is 2 800 mm, die gap is 0.45 mm, melt temperature is 235–245 °C, and chill roll temperature is held at 18–25 °C. The terminal film is a 23 µm machine stretch film that is pre-stretched to 200–250% on pallet-winding equipment. In industrial formulations, the addition of low-MFR mLLDPE at 25 wt% shifts the balance toward dart impact while retaining cast film draw; published data for this specific configuration is limited. Puncture resistance is evaluated under ASTM D5748-19, elongation at break under ISO 527-3:2018, and coefficient of friction under ASTM D1894-14. A production-scale failure mode is edge tear propagation at die lip temperatures below 220 °C, because the higher-viscosity core layer exits the die edges with slower relaxation and creates a transverse thickness band that initiates tear. Maintaining the die lip edge temperature above 225 °C and using LDPE edge encapsulation layers is required to prevent this defect. Surface condensation at relative humidity above 85% in coastal warehouses produces water on the granules that lowers melt output and can create gel voids at the die lip. Compliance for stretch film is industrial rather than food-contact; the film is assessed under REACH 1907/2006 Annex XVII for restricted substances.

Woven polypropylene sack lamination utilises mLLDPE 1018 in a 30–35 µm blown coating web that is subsequently adhesive-laminated or extrusion-laminated to the woven PP substrate. The film layer is formulated with 55–65 wt% mLLDPE 1018, 20–25 wt% LDPE 2420H, 10–15 wt% polyolefin plastomer, and 3–5 wt% white masterbatch. The plastomer is required to lower low-temperature sealing brittleness and improve interlayer adhesion when the film is run through a thermoplastic adhesive lamination nip at 120–160 °C. The blown film step uses a die gap of 2.2 mm, a blow-up ratio of 2.0–2.5, and a melt temperature of 180–200 °C; the lower melt temperature reduces oxidative gel formation in the plastomer phase but increases backpressure because the mLLDPE 1018 melt viscosity is higher. The terminal products are 25–50 kg woven sacks for cement, fertiliser, and petrochemical granules. Delamination on the production line occurs when the melt temperature at the lamination nip falls below 120 °C, because the polyethylene layer does not flow into the woven PP interstices; above 170 °C, the PP substrate shrinks and causes edge curl. When food contact is claimed, the film layer is assessed under EU Regulation 10/2011 and GB 4806.7-2016; otherwise the final sack is handled as an industrial packaging article. Mechanical performance is assessed by ISO 527-3:2018 for elongation, ISO 6383-2:1983 for tear, ISO 7765-1:1988 for impact, and ASTM D882-18 for tensile properties. The web is corona treated to 40 dyn/cm before lamination to ensure adhesion.

Stand-Up Pouch Sealant Web Coextrusion and the 88–95 °C Seal Window

The sealant web in dry food and pet food stand-up pouches is a five-layer coextruded blown film in which mLLDPE 1018 is positioned in the sealant layer at 80 wt% with LDPE 2420H at 10 wt% and a polyolefin plastomer at 10 wt%. The total film thickness is 60 µm, with the sealant layer occupying 10–15 µm. The five-layer line uses a 300 mm die, a die gap of 2.0 mm, and a blow-up ratio of 2.0:1; melt temperature is maintained at 195–205 °C to prevent additive degradation while keeping the plastomer phase dispersed. The blown web is later adhesive-laminated to a BOPET or BOPP print web. The sealant layer is designed to initiate sealing at 88–95 °C as measured by ASTM F2029-16, allowing the pouch converter to run heat seal bars at 120–140 °C without burning through the outer printed web. Hot tack is tested at 0.2 s dwell and 0.3 MPa jaw pressure to confirm that the sealant layer holds the pouch weight during form-fill-seal transfer. A known failure mode is hot tack loss when the sealant layer thickness drops below 8 µm, because the mLLDPE phase cannot form a continuous seal across the zipper or spout area. Another limitation is that erucamide slip in the sealant layer above 1 200 ppm reduces pouch seal strength after lamination and promotes delamination at the printed web interface. Terminal products are 1–5 kg stand-up pouches for dry pet food, kibble, rice, and powdered beverage mixes. Food-contact compliance is required and tested under EU Regulation 10/2011 with simulant E for dry foods, FDA 21 CFR 177.1520(c), and GB 4806.7-2016; the adhesive lamination system must separately comply with EU Regulation 10/2011 Annex I. Mechanical verification uses ISO 527-3:2018 and ASTM F88/F88M-21.