| HS Code | 520137 |
| Density | 0.918 g/cm3 |
| Melt Flow Rate | 2.0 g/10min |
| Tensile Strength At Yield | 12 MPa |
| Elongation At Break | 500% |
| Vicat Softening Point | 94 °C |
| Brittleness Temperature | -70 °C |
| Melting Point | 122 °C |
| Shore Hardness | D 50 |
| Environmental Stress Crack Resistance | >500 h |
| Film Haze | <8% |
As an accredited Daqing Petrochemical LLDPE 7042 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 25 kg LLDPE 7042 in plastic-lined woven bags, palletized and shrink-wrapped for safe transport. |
| Container Loading (20′ FCL) | 20′ FCL container loading of Daqing Petrochemical LLDPE 7042 resin pellets, packed in woven bags, palletized and securely stowed. |
| Shipping | Daqing Petrochemical LLDPE 7042 is supplied as free-flowing pellets, typically packed in 25 kg woven bags with PE liners or flexible bulk bags. Shipments should be containerized, kept dry, and protected from heat and direct sunlight to preserve quality during transit. |
| Storage | Store Daqing Petrochemical LLDPE 7042 in a cool, dry, well-ventilated warehouse, protected from direct sunlight, heat, and open flames. Keep bags sealed and intact, away from strong oxidizers and ignition sources. Avoid stacking excessively high to prevent deformation, and maintain cleanliness to minimize dust accumulation. |
| Shelf Life | Daqing Petrochemical LLDPE 7042 has an indefinite shelf life when stored in dry, cool conditions away from direct sunlight. |
Melt temperature control in agricultural greenhouse film directly affects UV stabilizer retention and anti-drip agent migration. For 7042-based monolayer or three-layer greenhouse structures of 120–200 µm, melt temperature is held at 185–205 °C. Higher temperatures deactivate low-molecular-weight HALS packages before the film reaches the field; lower temperatures reduce dispersion of slip and anti-fog concentrates. Greenhouse film formulations combine 70–85 wt% 7042 with 10–20 wt% EVA containing 8–14 wt% vinyl acetate and 5–10 wt% UV masterbatch. The EVA phase improves light diffusion and infrared retention. Film is produced on three-layer blown film lines with a die diameter of 250–500 mm, die gap 1.8–2.4 mm, BUR 2.0–2.5, and frost line 500–900 mm above the air ring. Long-term outdoor weathering under ISO 4892-2 or ASTM D4329 is evaluated after 3,000–6,000 h exposure. The practical limit for 7042 in greenhouse film is tensile impact retention below 50% after 4,000 h when a non-UV-stabilized formulation is used; formulation must therefore include UV stabilizers at no less than 0.4 wt% total HALS. Anti-drip performance is assessed by hot-water condensation testing at 60 °C according to EN 13206 Annex D. Storage of reworked greenhouse film should not exceed 6 months at ambient temperature above 30 °C because acid scavenger depletion shifts the gel index upward. Avoid dry-blending 7042 with EVA copolymers on screw designs without mixing elements; melt instability is observed on plain compression screws shorter than 24:1.
Industrial shipping sacks from 7042 at 60–100 µm gauge exhibit 15–25% higher screw torque than equivalent LDPE formulations because of the resin’s shear-thinning profile. Extruders with grooved feed sections and L/D 30:1 are preferred; plain feed machines below 25:1 develop melt pressure above 350 bar when 7042 is run neat. Blending 30–50 wt% LDPE lowers head pressure by 10–18% and permits stable bubble operation at BUR 2.0–2.5. The die gap is widened to 1.8–2.4 mm to avoid sharkskin melt fracture at output rates above 120 kg/h on 350 mm dies. Film is converted into gusseted sacks and liners requiring puncture resistance after filling. Slow puncture by ASTM D5748 often ranges from 30–60 N for 80 µm film depending on blend ratio. Seal strength by ASTM F88/F88M-21 at 130–150 °C jaw temperature should exceed 12 N/25 mm for 40 µm films. If the sack is used for dry chemicals, the outer layer can be loaded with 2–5 wt% slip/antiblock masterbatch; higher loadings reduce seal integrity. The main operational boundary is extrusion of neat 7042 below 180 °C melt temperature, which produces unmelts and gel streaks in the film; above 230 °C, oxidation byproducts accumulate on the inner die lip and produce die lines.
On cast stretch film lines running LLDPE 7042 at 15–40 wt% in the core layer with metallocene LLDPE skins, line speed is restricted by draw resonance rather than extruder capacity. The grade’s MFI of 2.0 g/10 min limits neat extrusion through a cast die lip of 0.5–0.8 mm; at screw speeds above 80 rpm on a 120 mm extruder, melt temperature exceeds 260 °C and gel levels rise. Chill roll temperature is set at 18–25 °C for 10–20 µm machine gauges; higher chill roll temperatures of 30 °C are used only for film above 20 µm to reduce blocking. Pre-stretch ratios in pallet wrapping are 200–300%. Puncture resistance by ASTM D5748 for 20 µm three-layer cast film containing 30 wt% 7042 typically falls between 12–18 N. Elongation at break by ASTM D882 in the machine direction exceeds 400%. Because 7042 is butene-based, its optical contribution in a cast skin layer is lower than hexene metallocene grades; haze increases by 2–5 percentage points when the grade replaces a metallocene skin resin. The practical boundary is 20 µm cast film at 300 m/min; above this speed, edge bead thickness variation exceeds ±8% and leads to telescoped rolls on automatic pallet wrappers.
| Process | Melt temperature | Die gap | Draw parameter | Key control limit |
|---|---|---|---|---|
| Blown film | 180–210 °C | 1.6–2.4 mm | BUR 2.0–3.0 | Frost line 5–8 die diameters |
| Cast stretch film | 240–260 °C | 0.5–0.8 mm | Line speed 150–300 m/min | Edge bead ±8% |
| Extrusion lamination | 280–310 °C | Internal deckle | Coat weight 12–25 µm | Neck-in 10–20 mm at 30 wt% 7042 |
Extrusion lamination with 7042 is limited by its low melt index relative to conventional coating grades. The resin is introduced only as a 20–40 wt% blend partner with an LDPE coating grade of MFI 7–12 g/10 min to maintain melt curtain stability. Extruder L/D must be 30:1 or higher with a barrier screw; melt temperature at the die is 280–310 °C. Neck-in of the melt curtain is reduced by 10–20 mm at 300 mm die width when the 7042 fraction is 30 wt% compared with neat LDPE, but draw-down below 12 µm coat weight becomes unsteady. Adhesion to 20 µm aluminum foil is developed by ozone treatment at 2–4 g/h and corona pretreatment of the substrate at 42–46 dyn/cm. Heat seal strength by ASTM F2029 for 15 µm coating on 12 µm PET is typically in the range 8–14 N/25 mm. Hot-tack performance is superior to neat LDPE at 105–120 °C, which supports vertical form-fill-seal packaging of powdery products. The limitation is melt pressure: at 40 wt% 7042 loading, extrusion lamination dies with internal deckle systems may exceed 200 bar; above this loading, melt curtain tears occur at line speeds below 80 m/min.
| Standard designation | Property / scope | Documentation requirement |
|---|---|---|
| ASTM D1238-20 / ISO 1133-1:2022 | Melt flow rate | CoA value 2.0 g/10 min ± 0.3 |
| ISO 1183-1:2019 / ASTM D1505-18 | Density | CoA value 0.918–0.922 g/cm³ |
| ASTM D882-18 | Film tensile properties | Internal specification for MD/TD yield and elongation |
| ASTM D1709A | Dart impact | Internal specification for 25 µm blown film; no universal grade-specific limit |
| ASTM F88/F88M-21 | Seal strength | Minimum after specified seal temperature profile |
| FDA 21 CFR 177.1520(c) | Food contact resin | Lot-level supplier certification |
| EU No 10/2011 Annex I | Overall migration | Compliance declaration from converter |
| EN 13206 | Agricultural cover film | Optional, based on end-use market |
Frozen food pouches made with 7042 require a coextruded structure because monolayer film of this butene grade loses dart impact steeply below -20 °C. In three-layer films of 60–90 µm, 7042 is placed in the sealant layer at 60–80 wt% blended with plastomer or ULDPE to achieve seal initiation below 100 °C. The core layer contains HDPE or medium-density PE to raise overall modulus. Equipment uses a 3-layer blown film line with die gap 1.8–2.2 mm, BUR 2.0–2.8, and frost line 5–8 die diameters. Dart impact by ASTM D1709A for 80 µm film is evaluated at -18 °C after conditioning per ASTM D618; typical values are 120–220 g for high-burst gusseted structures. Published data for neat 7042 monolayer frozen food packaging is limited; converters therefore test each blend. Seal-through-contamination performance benefits from the broad molecular weight distribution of 7042, but the film must contain no more than 1,500 ppm erucamide slip to avoid seal strength decay below 8 N/25 mm. The resin is incompatible with high levels of certain peroxide-initiated silane grafting used in adjacent production campaigns; purge transitions must use a dedicated PE purge compound for 45–60 min at 200 °C.
For surface protection film coextruded as a 35–60 µm three-layer structure on steel or aluminum profiles, LLDPE 7042 is compounded in the core at 50–70 wt% with LDPE to balance adhesion and unwinding. The skin layers contain ethylene-vinyl acetate or pressure-sensitive adhesive concentrates at 5–15 wt%. Cast film lines with die gap 0.5–0.8 mm and chill roll temperature 15–22 °C are preferred for thinner gauges; for gauges above 60 µm, blown film with BUR 2.0–2.5 is used. Peel adhesion to stainless steel by ASTM D3330 Method A should remain below 1.5 N/25 mm for high-gloss sheet protection, but after oxidation at 70 °C for 7 days, adhesion must not rise above 4 N/25 mm. The main processing hazard is gel contamination from degraded adhesive masterbatch; melt temperature is capped at 220 °C and die residence time below 8 min. 7042 contributes moderate clarity; light transmission at 40 µm is 85–90% when the grade is used in the core only. Published data for this specific configuration is limited, and converters validate peel force after each masterbatch lot change.
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Daqing Petrochemical LLDPE 7042 is a butene-1 comonomer linear low density polyethylene supplied in pellet form for blown film extrusion, lamination film and general-purpose flexible packaging. The grade designation is also encountered as DFDA-7042 in PetroChina film-grade series, and the resin is manufactured on a gas-phase polymerization line. It is typically released against the class-level specification in GB/T 11115-2009, with lot-level QC values reported on the certificate of analysis. Typical melt mass-flow rate is 1.8–2.2 g/10 min at 190°C under 2.16 kg load according to GB/T 3682.1-2018; density is controlled in the range 0.918–0.922 g/cm³ by GB/T 1033.2-2010. Tensile yield strength on compression-moulded specimens is generally not less than 8.0 MPa, with tensile break strength not less than 12 MPa and elongation at break not less than 500% under GB/T 1040.2-2022. The grade is not predried for ordinary extrusion, but surface moisture arising from cold-bulk warm-building transfer should be considered if visible pellet condensation appears.
Before line start-up, the certificate of analysis should be checked for density, melt mass-flow rate, ash and gel count. Density drift of more than 0.002 g/cm³ across lots can shift film stiffness and seal initiation temperature even when both lots remain within specification. Melt index drift from 1.8 g/10 min to 2.2 g/10 min changes extrusion pressure and output; on a 90 mm line, pressure variation may exceed 5 MPa at constant screw speed. The table below summarizes incoming QC release ranges used for film-grade LLDPE 7042.
| Test property | Release range or typical film value | Standard |
|---|---|---|
| Melt mass-flow rate | 1.8–2.2 g/10 min | GB/T 3682.1-2018; ISO 1133-1:2011 |
| Density | 0.918–0.922 g/cm³ | GB/T 1033.2-2010; ISO 1183-1:2012 |
| Tensile yield strength | ≥8.0 MPa | GB/T 1040.2-2022; ISO 527-2:2012 |
| Tensile break strength | ≥12 MPa | GB/T 1040.2-2022; ISO 527-2:2012 |
| Elongation at break | ≥500% | GB/T 1040.2-2022; ISO 527-2:2012 |
| Dart impact on 25 μm blown film | 80–110 g typical | GB/T 9639.1-2008; ASTM D1709-16ae1 |
Blown film extrusion on a 90 mm single-screw line with a 30:1 L/D barrier screw and 2.5:1 compression ratio typically operates with barrel temperatures from 175°C in the feed zone to 220°C in the metering zone, adapter 210°C, lower die 210°C and upper die 215°C. Because LLDPE 7042 has a narrower molecular weight distribution and lower melt strength than high-pressure LDPE, the bubble is less stable at high take-off speeds; internal bubble cooling and a dual-lip air ring are commonly required above 25 m/min line speed. The die gap is generally set at 1.8–2.4 mm, with a blow-up ratio of 2.2–3.0:1 and frost line height 8–12 times the die diameter. At 60 rpm on a 90 mm extruder, melt pressure at the screen changer is normally 30–45 MPa; motor load approaches 75–85% of rated torque. For this equipment class, published data specific to Daqing LLDPE 7042 output are limited, but similar C4-LLDPE grades show 180–220 kg/h on a 90 mm line. Melt temperature should not exceed 235°C to limit oxidative gel formation.
Substitution of high-pressure LDPE 2426H with LLDPE 7042 alters both process and film properties. The LLDPE grade provides higher dart impact and tensile strength but lower optical clarity and lower melt strength. On a typical 55 mm blown film line, the bubble may require higher neck height and reduced take-up ratio; melt pressure at the die increases by approximately 15–25% because of higher shear viscosity. The film shows a measured dart impact increase from 50–70 g to 80–110 g per GB/T 9639.1-2008 on 25 μm film, while tensile yield strength can increase from 10 MPa to 12 MPa depending on blow-up ratio. Haze typically increases from 5–9% to 9–14% per GB/T 2410-2008, which excludes the grade from high-clarity transparent packaging. Because the melt tension is lower, the bubble may oscillate at frost line heights above 12 die diameters; in such cases, a high-pressure LDPE or HDPE stiffener is added at 10–20 wt% to stabilize the bubble. Published data for the exact Daqing LLDPE 7042 versus LDPE 2426H on a specific line are limited.
Gel counts in LLDPE 7042 film increase when melt temperature exceeds 235°C, when residence time in the die exceeds 15 min, or when regrind containing oxidized film is reintroduced above 20 wt%. The narrow density window reduces fish-eye potential, but film can still contain gel particles from degraded extruder dead spots. It is advisable to purge the line with HDPE or LDPE at 200–220°C after each campaign using LLDPE 7042; purging with PVC or halogenated polymers is contraindicated because of corrosive degradation products. Slip and antiblock masterbatches based on erucamide and diatomaceous earth are added at 2–5 wt% to reduce blocking, but these additives lower hot tack and seal strength and should be validated under the final sealing conditions.
When film thickness is reduced below 25 μm, the user should revalidate dart impact, Elmendorf tear, seal strength and gel count. For 25 μm film, dart impact of LLDPE 7042 typically falls from 80–110 g to 45–65 g at 15 μm when melt temperature is below 220°C; at melt temperature above 230°C, dart impact may partially recover from improved homogenization but gel risk increases. Tear propagation in the machine direction is lower than in the transverse direction; Elmendorf tear should be measured on both axes according to ASTM D1922-15. Seal initiation temperature for the grade is generally 108–115°C at 1 N/15 mm seal strength, but this depends on dwell time and jaw pressure. The narrow melt index window of 1.8–2.2 g/10 min permits stable gauge control at 15 μm only with automatic gauge control and a bubble cage. Without these aids, thickness scatter can exceed ±3 μm on contact-gauge systems.
Cast film lines running LLDPE 7042 use higher stock temperatures, typically 240–260°C at the die, because lower neck-in and high line speed require higher melt fluidity. The grade is more often used in blown film because its butene comonomer gives lower hot tack and a broader sealing range than metallocene hexene grades. For cast film, vacuum box extraction should be set to manage trim edge and reduce edge curl; winding tension should be tapered from 120 N to 60 N to prevent blocking. The narrower molecular weight distribution causes less draw resonance than LDPE but more than hexene mLLDPE. Published data for this specific Daqing grade on cast film lines are limited, so line trials with target gauge and winding tension should be used before commercial conversion.
When a converter considers replacing a metallocene hexene mLLDPE with Daqing LLDPE 7042, four properties usually control the decision: optics, hot tack, dart impact and extrusion pressure. mLLDPE grades typically have haze below 5% on 25 μm film per GB/T 2410-2008, while LLDPE 7042 is generally 9–14%; therefore clear barrier display films are not a direct substitution. Hot tack strength and seal initiation of mLLDPE are superior: metallocene grades may achieve hot tack of 3–5 N/25 mm at 95–105°C, whereas LLDPE 7042 reaches the same seal strength near 110–120°C and with lower hot tack. Conversely, LLDPE 7042 has a broader processing window and lower melt pressure at equivalent output because of its broader molecular weight distribution; it also tolerates higher levels of post-consumer recycled film without catastrophic bubble instability. The substitution should be validated by measuring dart impact per ASTM D1709-16ae1, Elmendorf tear per ASTM D1922-15, and hot tack per ASTM F1921-98 on the specific line.
After film is produced, printing and lamination require surface oxidation. Fresh LLDPE 7042 film typically has surface wetting tension of 34–36 mN/m; corona treatment can raise it to 40–42 mN/m according to ASTM D2578-23. If erucamide slip masterbatch is used, treatment should be performed shortly before printing because slip additive migrates to the surface and lowers surface energy over 24–72 h; migration kinetics are accelerated above 35°C. For lamination film, an untreated surface can cause delamination; a minimum 42 mN/m is generally required for solventless lamination adhesives.
Additive masterbatches are dry-blended at the hopper; segregation is possible because pellet shape and density differ. The use of a low-speed paddle mixer and continuous gravimetric dosing reduces concentration drift to ±0.5 wt% of target. At higher line speeds above 150 kg/h, the residence time distribution narrows, but dispersion of diatomaceous earth antiblock improves if the masterbatch is pre-dispersed in an LDPE carrier with melt index 2–4 g/10 min. Poor dispersion can create film spots that reduce dart impact by 10–20%.
Food-contact suitability for LLDPE 7042 is assessed under FDA 21 CFR 177.1520(c) when the resin is used neat and under EU Regulation 10/2011 with migration testing according to food type; converters are responsible for verifying specific migration limits for the finished package. The grade is not formulated with heavy-metal stabilizers and is generally considered compliant with the REACH SVHC candidate list, but antioxidant package details require the supplier lot-specific safety data sheet. RoHS compliance should be claimed only after testing the finished article for lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls and polybrominated diphenyl ethers. The resin should be stored in unopened containers at 25–35°C and protected from direct sunlight; bulk outdoor storage is acceptable only if the silo is purged with dry air at a dew point below -20°C to prevent condensation.
