| HS Code | 357663 |
| Product Name | Guangzhou Petrochemical LLDPE 7042 |
| Polymer Type | Linear Low Density Polyethylene (LLDPE) |
| Comonomer | Butene-1 |
| Density | 0.918 g/cm³ |
| Melt Flow Rate | 2.0 g/10 min (190°C, 2.16 kg) |
| Tensile Strength At Yield | 12 MPa |
| Elongation At Break | 500% |
| Flexural Modulus | 280 MPa |
| Vicat Softening Temperature | 100 °C |
| Melting Point | 120 °C |
| Brittleness Temperature | -70 °C |
As an accredited Guangzhou Petrochemical LLDPE 7042 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Guangzhou Petrochemical LLDPE 7042 is supplied in 25 kg woven bags, sealed for safe handling and storage. |
| Container Loading (20′ FCL) | 20′ FCL container loading of Guangzhou Petrochemical LLDPE 7042 resin, ensuring secure, efficient, and safe transport. |
| Shipping | Ship Guangzhou Petrochemical LLDPE 7042 as granules/pearls in dry, clean woven bags or bulk containers. Protect from moisture, direct sunlight, and high temperatures. Ensure containers are well-ventilated and secured, avoiding sharp objects. No hazardous classification; handle with standard industrial safety practices. |
| Storage | Store Guangzhou Petrochemical LLDPE 7042 in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and open flames. Keep packaging sealed to prevent moisture contamination and dust buildup. Avoid contact with strong oxidizing agents. Maintain good housekeeping to minimize static and fire risk. No special temperature control is needed under normal conditions. |
| Shelf Life | Shelf life is typically 12 months when stored in original packaging, in a cool, dry, well-ventilated area away from sunlight. |
In blown film conversion of Guangzhou Petrochemical LLDPE 7042, the screw design and die gap are set around the butene-copolymer melt rheology. The resin is specified with a nominal density of 0.920 g/cm³ and a melt flow rate of 2.0 g/10 min under 2.16 kg at 190 °C per ISO 1133-1:2022 and ASTM D1238-20. Single-screw extruders with 25:1–30:1 L/D and a barrier mixing section are used to reduce melt temperature inhomogeneity. A die gap of 1.8 mm–2.5 mm is preferred over the 0.8 mm–1.2 mm gap commonly used for LDPE. The wider die gap lowers shear stress at the die lip and delays shark-skin melt fracture until melt temperature reaches 195 °C. Dual-lip air rings with internal bubble cooling maintain bubble geometry when layflat width exceeds 1,200 mm and frost line height is held at 5–8 die diameters. For general packaging film at 25 µm–80 µm gauge, a blow-up ratio of 2.2:1–3.0:1 is maintained. Film property verification includes ASTM D882-18 tensile, ASTM D1922-15 Elmendorf tear, ASTM D1709-16a dart impact, and ASTM D1003-21 haze. When 7042 is blended with LDPE at 20 wt%–30 wt% addition, melt pressure typically drops by 10%–15% and bubble stability improves, but dart impact and puncture energy decrease. Slip and antiblock additions are commonly 400 ppm–800 ppm erucamide and 2,000 ppm–5,000 ppm synthetic silica. Published data for the exact gauge-band behavior at line speeds above 150 m/min are limited, and converters generally map their own air-ring settings.
Draw resonance in cast film conversion of 7042 is governed by the melt strength of the butene comonomer, the air-gap length, and the melt temperature at the die lip. On high-speed cast film lines, the polymer is plasticated in a 75 mm–90 mm single-screw extruder with L/D 30:1–33:1, and the flat die with flex lip is held at 220 °C–240 °C. The air gap between die exit and chill roll is set at 100 mm–150 mm for films of 15 µm–25 µm. Chill roll temperature is maintained at 20 °C–30 °C with closed-loop water circulation and a vacuum box or air knife to pin the web. Draw resonance typically initiates when the draw ratio exceeds 18:1 or when melt temperature rises above 245 °C. The addition of 1.5 wt%–3.0 wt% polyisobutylene or a selected cling masterbatch reduces cling force variability and modifies surface roughness without eliminating draw resonance. Coefficients of friction are assessed by ASTM D1894-14, and tensile elongation is checked by ASTM D882-18. Because 7042 is a butene-based LLDPE, the film exhibits lower ultimate stretch before failure than metallocene or higher alpha-olefin stretch grades. Converters running above 250% pre-stretch should validate the raw film on their own wrapping equipment.
For food-contact cast film, the documentation matrix used by converters includes the following compliance framework:
| Framework | Reference point | Typical verification parameter |
|---|---|---|
| US FDA | 21 CFR 177.1520 | Olefin polymer extractives and end-use condition compliance |
| EU | Regulation (EU) No 10/2011 Annex I | Overall migration limit 10 mg/dm² |
| EU | Regulation (EU) No 10/2011 Annex II | Specific migration limits for authorized additives |
| REACH SVHC | Candidate List | Substances above 0.1% w/w |
Agricultural film lines running 7042 at layflat widths above 1,500 mm depend on stabilizer masterbatch dispersion and anti-drip additive migration. A typical 150 µm greenhouse film formulation uses 100 phr 7042, 10 phr–20 phr LDPE with fractional melt index, and 5 phr–8 phr anti-drip masterbatch based on glycerol monostearate. UV stabilization is achieved with a hindered amine light stabilizer system at 0.15 wt%–0.35 wt% and a benzotriazole UV absorber at 0.10 wt%–0.20 wt%. The film is evaluated for haze by ASTM D1003-21, for tensile after accelerated weathering by ISO 4892-2:2021, and for total luminous transmittance by ASTM D1003-21. A processing constraint on high-width lines is bubble oscillation caused by uneven air-ring impingement and unbalanced cooling. This is controlled by setting frost line height below 8 die diameters and maintaining melt temperature at 190 °C–205 °C. Silage film produced from 7042 at 80 µm–120 µm thickness requires low-temperature puncture resistance after outdoor exposure. Butene comonomer grades show lower puncture retention than hexene LLDPE. Converters using 7042 in silage wrap therefore apply 10 wt%–20 wt% metallocene LLDPE to improve impact at -20 °C storage conditions.
The molding window for 7042 in thick-walled closures and crates is constrained by the semicrystalline solidification rate and the melt viscosity of the narrow molecular weight distribution. Barrel temperatures are ramped from 180 °C at the feed throat to 210 °C at the nozzle. Mold temperature is held between 15 °C and 30 °C; lower mold temperatures increase orientation but create higher internal stress. Hydraulic injection pressure is set at 60 MPa–90 MPa, and holding pressure is adjusted to 45 MPa–65 MPa to compensate for volumetric shrinkage. On a 500 t–1,200 t clamp unit, shot size is kept at 50%–70% of barrel capacity to limit residence time and thermal oxidation. Mold shrinkage measured by ISO 294-4:2018 ranges from 1.5% to 2.5%, with the upper end occurring in sections above 4 mm wall thickness. Gate design uses a direct sprue gate or an edge gate with a land length below 1 mm; pin gates below 0.8 mm cause high shear and early freeze-off. The material does not require pre-drying below 60% relative humidity. Surface condensation above that threshold produces silver streaks and should be addressed with a hopper dryer at 60 °C–70 °C for 2 h. Flexural properties are tested by ISO 178:2019, and notched Izod impact is reported under ASTM D256-23. Published data for long-term creep in 7042 crate applications are limited.
When 7042 is pulverized to a mean particle size of 35 mesh (500 µm) or 50 mesh (297 µm), the powder flow and densification in rotational molding are controlled by particle shape and the melting peak of the butene copolymer. The mold is heated in a forced-air oven to 280 °C–300 °C, and internal air temperature is held at 190 °C–200 °C for bubble removal. The cooling phase is separated into air cooling and water mist cooling to control warpage on flat panels. The low density of 0.920 g/cm³ gives higher impact strength than HDPE at equivalent wall thickness, but the modulus is lower and creep resistance is reduced under continuous load. Parts are tested for tensile elongation by ISO 527-2:2012 and for flexural modulus by ISO 178:2019. A recognized limitation of 7042 in rotational molding is the slower crystallization of the butene branch structure compared with MDPE or HDPE. This extends the molding cycle and increases oxidation risk if oven air temperature exceeds 300 °C. Antioxidant packages suitable for long oven residence are required. Published data for this specific configuration are limited.
7042 is used as a carrier resin in color and additive masterbatches because the MFR of 2.0 g/10 min provides sufficient wetting of pigment aggregates and later letdown compatibility in LLDPE film and injection applications. Compounding is performed on a co-rotating twin-screw extruder with L/D 40:1–48:1, screw speed 300 rpm–600 rpm, and specific energy input 0.18 kWh/kg–0.25 kWh/kg. Pigment loadings of 30 wt%–50 wt% for organic pigments and 50 wt%–60 wt% for inorganic titanium dioxide are processable, but letdown ratios in film must be confirmed by filter pressure rise on a 25 µm screen pack. Dispersion quality is checked by film gel counts and differential pressure measurement. The addition of processing aid fluoropolymer at 200 ppm–500 ppm reduces die deposits and gel formation during repeated extrusion passes. The main incompatibility is with high levels of hygroscopic fillers; calcium carbonate above 60 wt% requires side-feeding and venting to prevent steam degradation and surface defects. The final article performance must be revalidated under the relevant end-use standard because masterbatch dilution shifts the additive concentration profile.
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Polyethylene grade Guangzhou Petrochemical LLDPE 7042 is a butene-comonomer linear low-density polyethylene produced by Sinopec Guangzhou Petrochemical. The grade designation is a commercial identifier rather than an encoded ISO classification, and the resin is supplied as pelletized general-purpose film material. It is polymerized using a Ziegler-Natta catalyst system in a low-pressure process, producing a linear backbone with short-chain branches derived from butene comonomer. This structure distinguishes the material from autoclave or tubular low-density polyethylene, whose long-chain branching contributes a different melt-elasticity signature. Typical datasheet values give a melt mass-flow rate of 1.9–2.1 g/10 min at 190 °C/2.16 kg and a density range of 0.918–0.922 g/cm³. These coordinates place the grade in the lower portion of the linear-low-density polyethylene density spectrum and make it suitable for film applications requiring tensile yield stress of ≥8.0 MPa to ISO 527-2:2012, tear resistance to ASTM D1922, and seal initiation measurable to ASTM F88. The resin is supplied with standard antioxidant and processing stabilizer packages; the precise additive formulation is disclosed through the certificate of analysis, not by the grade number alone.
Specification compliance is normally assessed against a lot-specific certificate of analysis. Density is determined by ISO 1183-1:2019 or GB/T 1033.2-2009 immersion methods, with the typical range for 7042 falling between 0.918 g/cm³ and 0.922 g/cm³. Melt mass-flow rate is measured at 190 °C under a 2.16 kg load following ISO 1133-1:2022 or GB/T 3682.1-2018; the nominal range is 1.9–2.1 g/10 min. Tensile properties are evaluated on compression-moulded sheets or blown-film specimens according to ISO 527-2:2012 or GB/T 1040.2-2022. Published tensile yield stress for the grade is typically ≥8.0 MPa, with elongation at break typically ≥500%. Differential scanning calorimetry to ISO 11357-3:2018 typically records a peak melting temperature between 121 °C and 126 °C. Because density results from comonomer incorporation, the 0.918–0.922 g/cm³ range corresponds to a low-crystallinity regime; melting peak temperature and heat of fusion are lower than those of high-density polyethylene, reducing stiffness but improving impact and tear resistance as measured by ASTM D1709A and ASTM D1922. Density fluctuations within this range can shift film modulus and gas permeability, making lot-to-lot density control important for converters who certify film against tight mechanical specifications.
The following table consolidates indicative property coordinates for Guangzhou Petrochemical LLDPE 7042. These values are drawn from public technical literature and are not a substitute for lot-specific certificate-of-analysis limits.
| Property | Test method | Indicative range |
|---|---|---|
| Melt mass-flow rate | ISO 1133-1:2022, 190 °C/2.16 kg | 1.9–2.1 g/10 min |
| Density | ISO 1183-1:2019 | 0.918–0.922 g/cm³ |
| Tensile yield stress | ISO 527-2:2012 | ≥8.0 MPa |
| Tensile elongation at break | ISO 527-2:2012 | ≥500% |
| Peak melting temperature | ISO 11357-3:2018 | 121–126 °C |
The melt mass-flow rate value should not be interpreted as a complete viscosity specification. Polyethylene melts are shear-thinning, and a single point at 2.16 kg load does not describe flow at film-die shear rates. Capillary rheometry following ISO 11443 at 190 °C and 210 °C is recommended for die-pressure calculations. Gel permeation chromatography of Ziegler-Natta butene LLDPE grades generally shows broad molecular weight distribution; published polydispersity data for this specific grade is limited in the standard datasheet. The broader distribution tends to improve shear-thinning processability but can raise low-molecular-weight extractable levels relative to metallocene grades.
Beyond the standard property set, film converters measure optical and mechanical properties on finished film because pellet datasheets do not capture film-fabrication history. Haze is assessed to ASTM D1003, gloss to ASTM D2457, and dart impact to ASTM D1709A. The measured values are influenced by die gap, melt temperature, frost-line height, and gauge profile. Two film lots produced from the same resin lot can differ measurably if the bubble geometry and cooling rate are not held constant. This is particularly relevant for 7042 because its crystallization rate and crystal-size distribution change with quench intensity.
Because 7042 lacks long-chain branching, melt tension at bubble-forming shear rates is lower than that of an equivalent-MFR LDPE. Stable bubble formation on conventional blown-film lines is therefore controlled by die gap, frost-line height, and blow-up ratio rather than by melt elasticity alone. On a single-screw extruder with L/D 25:1–30:1 and a barrier screw, the resin is typically processed at melt temperatures from 185 °C to 215 °C. Die gaps of 1.6–2.0 mm are common for thin film, while 2.0–2.4 mm gaps are used for thicker gauge. A blow-up ratio of 2.0–2.5:1 and a frost-line height of 6–8 die diameters are typical starting points for high-stalk bulged-stem operation. Melt temperatures above 230 °C increase die-lip oxidation, gel formation, and smoke; the published upper melt-temperature limit is generally 240 °C for short residence-time operation only. Screw pressure and die body temperature should be monitored because worn screw clearances can create melt-temperature inhomogeneity and gauge bands.
Temperature profile settings vary with screw design and output. A typical downward-flat profile from feed to die is used to avoid overheating the melt. In barrier-screw extruders with L/D 28:1, zone settings from 150 °C at feed to 195–205 °C at the die are reported in film operations. The actual melt temperature should be measured with an immersion probe because screw shear can raise melt temperature above set values.
Thin films of 20 µm or less can be drawn on properly tuned lines. Thick-gauge film above 80 µm often requires blending with LDPE or a higher-melt-strength resin to stabilize the bubble. Without modification, small-die production of thick-gauge 7042 may exhibit low-frequency bubble sway and draw resonance at high take-off speeds. The addition of 10–30 wt% LDPE 2426H increases melt strength and widens the stable operating window. The same blend reduces the dart impact and puncture resistance characteristic of the linear component; the property trade-off is measurable by film impact testing to ASTM D1709A, puncture testing to ASTM D5748, and tear testing to ASTM D1922. In high-stalk operation, a 20 wt% LDPE blend typically reduces machine-direction tear more than transverse-direction tear, but published data for this specific blend ratio on Guangzhou 7042 is limited; line-specific trials are necessary.
If bubble instability appears after switching from LDPE to 7042, the first diagnostic step is to check die gap and internal bubble cooling rather than raising melt temperature. A die gap narrower than 1.6 mm can generate excessive shear heating and gel formation; a die gap wider than 2.4 mm can reduce draw-down and increase gauge variation. Frost-line height changes alter crystallinity and film toughness: a lower frost line quenches the melt more rapidly, reducing haze as measured to ASTM D1003 and increasing dart impact to ASTM D1709A in some structures, while also lowering machine-direction tear resistance to ASTM D1922.
Across agricultural film, industrial liner, and carrier-bag operations, 7042 is selected where moderate melt temperatures, downgauging capability, and film toughness are required. In agricultural greenhouse film, the carrier resin must be compounded or dry-blended with UV stabilizers and anti-fog additives; the base resin does not inherently provide weathering resistance. A converter running a 75 mm barrier-screw extruder with L/D 28:1 and a 300 mm die can maintain bubble stability at melt temperatures between 195 °C and 205 °C, with a layflat width of 1,200 mm when supported by internal bubble cooling. In industrial liner film, gauge uniformity is typically verified by in-line thickness profiling to ISO 4591 or ASTM F2251. The resin is also used in thin stretch-film formulations, but its butene comonomer content gives lower puncture and damage resistance than metallocene hexene grades under high pre-stretch; processors seeking consistent 200% machine-direction pre-stretch commonly evaluate mLLDPE-rich formulations instead. Food-contact applications require end-article verification under GB 4806.6-2016 and, where applicable, FDA 21 CFR 177.1520(c). Compliance depends on additive composition, migration limits, and end-use conditions, not on density or MFR alone.
In cast-film operations, 7042 may be processed at higher melt temperatures, but the absence of long-chain branching and the nominal 2.0 g/10 min MFR restrict ultra-high line-speed draw resonance control. Where cast film is the primary process, a C8 or mLLDPE grade with narrower MWD may provide better neck-in and gauge control. Published comparative data for this specific Guangzhou grade in cast film is limited; adaptation trials are required when replacing standard cast-film LLDPE.
Relative to a high-pressure LDPE such as 2426H, 7042 has higher tensile strength, higher elongation at break, better environmental stress-crack resistance measured to ASTM D1693, and lower melt elasticity. The linear grade is therefore less forgiving in bubble formation but more resistant to film splitting once the bubble is stable. LDPE 2426H is preferred where melt strength, shrink force, or high-clarity shrink film dominate; 7042 is preferred where downgauging and puncture resistance measured to ASTM D5748 matter. The shear-thinning response also differs: LDPE long-chain branching produces stronger shear thinning, while the linear backbone of 7042 retains a higher fraction of its low-shear viscosity at film-extrusion shear rates.
Against metallocene C6 LLDPE of similar density, the Ziegler-Natta butene material generally exhibits broader molecular weight distribution, lower dart impact to ASTM D1709A, lower Elmendorf tear to ASTM D1922, higher haze to ASTM D1003, and a higher seal-initiation temperature to ASTM F88. Metallocene grades typically provide better organoleptic properties and lower extractables due to narrower MWD and lower catalyst residues. The penalty is processability: mLLDPE substitution can increase melt pressure, torque, and die-lip shear heating on the same screw. Published data for the exact Guangzhou 7042-to-mLLDPE pressure differential is limited; converter-specific torque, die pressure, and gauge uniformity should be recorded before substitution.
The same numerical grade designation from other producers does not guarantee identical additive package, catalyst residue, or molecular architecture. Differences in butene incorporation distribution and antioxidant levels can shift melt mass-flow rate within the nominal range and alter film colour or odour. The certificate of analysis should be read alongside GB/T 3682.1-2018 and GB/T 1033.2-2009 values, but those tests do not resolve molecular weight distribution differences that govern extrusion pressure and film appearance.
Compared with high-density polyethylene film grades at density 0.945 g/cm³ and above, 7042 exhibits lower modulus and higher puncture and tear resistance. HDPE grades are preferred where moisture barrier, stiffness, and thermal resistance dominate; 7042 is preferred where sealability and damage tolerance matter. Water-vapour transmission rate is thickness-dependent and should be measured according to ASTM F1249; oxygen transmission rate is measured to ASTM D3985. Published values for this grade are not single-point properties because humidity, film thickness, and crystallinity control transport rates.
Blends of 7042 with metallocene C6 LLDPE are used to balance processability and toughness. A 20–40 wt% mLLDPE addition can offset the lower dart impact of the Ziegler-Natta base while preserving a wider melt-processing window than pure mLLDPE. The blend ratio is a compromise; pure mLLDPE film may exhibit better optics and seal performance, but the blended film is less sensitive to die-pressure fluctuations on older extruders.
In high-humidity storage conditions above 70% RH, pellet surface moisture may produce bubble defects even though polyethylene is not hygroscopic in bulk. If a cold silo discharges into a warm production hall, condensation is the dominant failure mode; pre-drying for 1–2 h at 60–70 °C is recommended only when surface moisture is verified. The resin should not be held above 240 °C for extended periods, and contact with copper-based stabilizers or certain halogenated additives may require compatibility testing because these can accelerate oxidative degradation. Regrind addition up to 20 wt% is common in non-critical film, but higher regrind fractions narrow the processing window and raise gel content. For medical or pharmaceutical packaging, no grade-specific biocompatibility certification is implied by the standard resin datasheet; end-article validation under ISO 10993 or relevant pharmacopoeia protocols is required.
