| HS Code | 647050 |
| Melt Flow Index 190 C 2 16 Kg | 0.50 g/10 min |
| Density | 0.920 g/cm³ |
| Melting Point Dsc | 122 °C |
| Vicat Softening Point A50 | 105 °C |
| Tensile Strength At Break Md | 32 MPa |
| Tensile Strength At Break Td | 24 MPa |
| Elongation At Break Md | 450 % |
| Elongation At Break Td | 700 % |
| Dart Drop Impact F50 1 Mil Film | 550 g |
| Haze 1 Mil Film | 12 % |
As an accredited Dow DOWLEX LLDPE 2645 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | DOWLEX LLDPE 2645 is supplied as free-flowing pellets in 25 kg multi-wall paper bags, approximately 1,000 kg per pallet. |
| Container Loading (20′ FCL) | Container Loading (20′ FCL): Load Dow DOWLEX LLDPE 2645 resin pellets in 25kg bags on pallets, maximizing weight up to 21 tonnes. |
| Shipping | Dow DOWLEX LLDPE 2645 is shipped as non-hazardous polyethylene resin pellets, typically in 25 kg bags or bulk containers. Protect from moisture, direct sunlight, and extreme heat. Keep packaging intact, store dry, and avoid contamination. Standard dry cargo transport is suitable. |
| Storage | Store DOW DOWLEX LLDPE 2645 pellets in a clean, dry, well-ventilated area, away from direct sunlight, heat sources, and excessive humidity. Keep containers sealed to prevent moisture pickup and contamination. Avoid generating dust; if dusting occurs, minimize ignition sources. No special storage hazards are expected under normal conditions. |
| Shelf Life | Store dry, cool, and protected from UV; shelf life is typically indefinite if conditions are properly maintained. |
Post-industrial regrind from 2645 edge trim and start-up film is reintroduced into waste bag film at addition levels of 20–40 wt%. The limiting variable is not melt filtration alone but the loss of dart impact consistency from repeated thermal history and oxidative chain scission. On a 70 mm grooved-feed blown film line, regrind at 30 wt% can be homogenized with a screen pack of 100/80/60 mesh and a melt pump, but gel count and gloss reduction increase when the regrind source contains paper labels or adhesive contamination. A high-shear dispersive mixing section with a Maddock element improves homogenization without increasing melt temperature beyond 220 °C. Film gauge for waste bag applications is typically 40–80 µm, with a blow-up ratio of 2.8:1 to 3.5:1 to enhance transverse tear resistance. At regrind levels above 40 wt%, published data for this specific configuration is limited; therefore, plant trials should monitor dart impact per ASTM D1709-16a and Elmendorf tear per ASTM D1922-15 on a minimum of three rolls per batch. Addition of 2–5 wt% LDPE with a melt index of 2.0 g/10 min improves bubble stability and allows regrind levels near 40 wt% without excessive neck-in. Terminal products include municipal waste bags, construction debris bags, and agricultural waste liners, where heat-seal strength is verified per ASTM F88/F88M-21.
In blown film extrusion of DOWLEX 2645 for heavy-duty industrial sacks, the resin is processed on grooved-feed single-screw extruders with L/D ratios between 24:1 and 30:1 and screw compression ratios of 2.5:1 to 3.5:1. A flat barrel temperature profile of 180–210 °C, with an adapter and die temperature of 210–225 °C, is used; melt temperatures above 240 °C are avoided because the low melt strength of an LLDPE with a melt index of 0.9 g/10 min (ASTM D1238, 190 °C/2.16 kg) and a density of 0.920 g/cm³ (ASTM D1505) can destabilize the bubble and accelerate gel formation. The die gap is set between 1.5 mm and 2.5 mm, and the blow-up ratio is maintained between 2.0:1 and 3.0:1 to balance machine-direction and transverse-direction tensile properties. Film thickness for industrial liners typically ranges from 75 µm to 200 µm, requiring frost line height of 6 to 10 die diameters and dual-lip air ring cooling to preserve gauge variation within ±5%. Unmodified 2645 resin does not include a slip or antiblock package; when reduced blocking force is required, 3,000–6,000 ppm erucamide slip and 2,000–4,000 ppm silica antiblock are introduced via masterbatch at the feed throat. Mechanical acceptance for heavy-duty sacks should reference ASTM D882-18 for tensile properties, ASTM D1922-15 for Elmendorf tear, ASTM D1709-16a for dart impact, and ASTM D5748-95(2019) for puncture resistance. Terminal products include bulk resin shipping sacks, mineral filler bags, and industrial waste liners where seams are heat-sealed at 120–160 °C and seal strength is validated per ASTM F88/F88M-21.
For agricultural silage film produced from 2645, the formulation window is dominated by UV stabilization and tackifier compatibility. A hindered amine light stabilizer system is added at 0.15–0.30 wt% active content, combined with 2–4 wt% of a carbon black or titanium dioxide masterbatch to limit UV transmission through a 25–40 µm film. The blown film line is operated with a blow-up ratio of 3.5:1 to 4.5:1 and dual-lip cooling to shift orientation toward the transverse direction, which improves puncture resistance but reduces machine-direction incremental modulus. A non-ionic tackifier at 0.5–1.5 phr is included in the outer surface layer to achieve bale adhesion without excessive unwind force. Puncture resistance is tested per ASTM D5748-95(2019), and tear propagation resistance per ASTM D1922-15. UV resistance is specified as a minimum 12-month outdoor exposure with retained elongation at break above 50% according to EN 13207:2001. REACH compliance is required for EU market access, and the film must be free of restricted phthalates and heavy metals. Die temperatures are kept below 215 °C because excessive residence time above 230 °C can volatilize the stabilization package and cause yellowing. Terminal products include round bale silage wrap, silage clamp covers, and maize storage bags.
For cast stretch film core layers, DOWLEX 2645 is processed on a multi-extruder cast line with a flat die width of 300–3,000 mm, a die gap of 0.5–1.0 mm, and a chill roll temperature of 15–25 °C. The unmodified resin is limited in extensibility; therefore, a metallocene polyethylene plastomer with a density of 0.902–0.910 g/cm³ is blended into the core at 20–30 wt% to raise elongation at break above 500% as measured by ASTM D882-18. The core layer comprises 60–80 wt% 2645, with the plastomer and 8–12 wt% polypropylene or HDPE in the skin layer to control cling release. Line speeds of 300–600 m/min are typical, and the air knife over the chill roll must suppress pinning defects without causing gauge bands. Pre-stretch capability of 150–250% is targeted for pallet unitization films of 15–25 µm thickness. High-speed winding requires roll hardness of 60–80 Shore OO to avoid telescoping during transit. Haze is specified by ASTM D1003-21 and gloss by ASTM D2457-13. Terminal products include machine film and hand stretch film for pallet wrapping, with load retention performance tested under ASTM D5459-17 or equivalent internal protocols.
| Application segment | Key property | Test standard | Typical condition |
|---|---|---|---|
| Heavy-duty industrial sack | Dart impact | ASTM D1709-16a | Method A, 38.1 mm dart, 23 °C |
| Agricultural silage film | UV retention of elongation | EN 13207:2001 | 12-month outdoor exposure |
| Cast stretch film | Elongation at break | ASTM D882-18 | 23 °C, 500 mm/min |
| Frozen food packaging | Sub-zero dart impact | ASTM D1709-16a | -18 °C conditioning |
| Dry powder FFS sealant | Seal strength | ASTM F88/F88M-21 | 150 mm/min jaw separation |
To maintain sub-zero dart impact in frozen food packaging, DOWLEX 2645 is blown at a thickness of 50–100 µm with a blow-up ratio of 2.0:1 to 3.0:1. The resin is blended with 10–20 wt% ultra-low density ethylene-alpha-olefin copolymer with a density below 0.910 g/cm³ to shift the ductile-to-brittle transition below -40 °C. Pre-test conditioning is performed at -18 °C for 24 h before dart impact testing per ASTM D1709-16a and tear testing per ASTM D1922-15. The film must resist pin-hole propagation from sharp-edged frozen vegetables; flex-crack resistance is evaluated by ASTM F392/F392M-21 Gelbo flex testing after 20 full flex cycles at -20 °C. Food-contact compliance is governed by FDA 21 CFR 177.1520(c) 3.1a and EU Regulation 10/2011 with overall migration below 10 mg/dm². Heat-seal initiation temperature falls between 100 °C and 120 °C, and seal strength is validated per ASTM F88/F88M-21. Processing must avoid melt temperatures above 230 °C to prevent gel formation that compromises dart impact. Terminal products include retail frozen vegetable bags, ice cube bags, and institutional frozen food pouches.
In dry powder form-fill-seal coextrusion, 2645 functions as the inner sealant layer combined with HDPE or MDPE for stiffness and moisture barrier. The sealant layer is extruded at 10–20% of total film thickness, with the final film typically 50–90 µm. The melt index of 0.9 g/10 min (ASTM D1238) provides sufficient melt strength for stable coextrusion at low layer ratios, while the density of 0.920 g/cm³ (ASTM D1505) contributes low-temperature sealability without excessive tack. Blown film lines with three to five extruders and a multi-layer die are used; the sealant layer melt temperature is controlled at 210–230 °C to maintain seal characteristics. Seal-through-contamination performance is evaluated by sealing across a folded seam containing a known quantity of calcium carbonate dust, with seal strength tested per ASTM F88/F88M-21. The finished pouch must show no pinholing after flex-crack testing per ASTM F392/F392M-21. Terminal products include dry beverage mix pouches, bakery premix sacks, and cement additive bags, where the LLDPE layer provides puncture resistance and hermetic seal integrity.
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Dow DOWLEX LLDPE 2645 is a linear low-density polyethylene resin produced via a solution polymerization process with octene-1 as the primary comonomer. The grade is positioned for cast film, extrusion coating, and lamination applications in which a nominal melt index of 2.3 g/10 min and a nominal density of 0.920 g/cm³ are required. The melt index is determined by ASTM D1238 at 190 °C/2.16 kg; density is determined by ASTM D792. The octene-1 architecture produces a short-chain branch distribution that increases tie-chain frequency in the amorphous phase relative to butene-1 copolymers of equal density and melt index. In 50 µm cast film, this architectural difference is observed as higher dart drop impact resistance under ASTM D1709-16a and higher Elmendorf tear resistance under ASTM D1922-15 than butene-based counterparts of equivalent melt index and density. The resin is supplied as natural pellets and does not require predrying unless pellets have been stored in cold, unheated warehouses and then transferred to a humid processing floor; surface condensation can generate gas splay at melt temperatures above 260 °C.
Density and melt index are not independent specifications. The combination of 0.920 g/cm³ density and 2.3 g/10 min melt index is intended to support thin-gauge drawdown without requiring excessive melt temperature. The typical peak melting temperature of 124 °C, measured by differential scanning calorimetry at 10 °C/min heating rate under ASTM D3418, is consistent with an octene-1 linear low-density polyethylene of this density. Vicat softening temperature is normally 105 °C under ASTM D1525 using a 10 N load and 50 °C/h heating rate. These thermal values are not absolute maximum service temperatures; they are used in heat-seal setting, hot-fill assessment, and package filling line configuration.
On a 75 mm single-screw extruder with 30:1 L/D and a barrier screw, a common starting barrel profile for DOWLEX 2645 is 180 °C in the feed zone, 200 °C in the compression zone, 220 °C in the metering zone, and 240 °C at the adapter. The melt temperature at the die lip should be maintained between 240 °C and 280 °C for cast film. At melt temperatures below 230 °C, unmelted resin domains and micro-gels produce optical haze bands and die-lines that cannot be corrected by adjusting the die bolts. At melt temperatures above 290 °C, oxidative chain scission becomes the dominant degradation pathway; gel particles with diameters above 0.5 mm can appear in the web after 6–8 h of continuous operation on a 2.0 m slot die. These particles are visible under dark-field optical inspection and correlate with a rise in backpressure fluctuation exceeding ±2 bar at the screen changer.
In extrusion coating, the resin is processed at lower melt temperatures than many high-pressure LDPE grades. A start-up melt temperature of 280 °C to 320 °C is used when coating paper, board, or foil. The higher end of this range promotes adhesion through surface oxidation but is limited by residence time in the adapter and die. When residence time exceeds 8 min, coating weight stability deteriorates and smoke generation increases. The die gap is typically 0.6–0.9 mm. Air gap is set between 100 mm and 200 mm; shorter gaps reduce neck-in but also reduce drawdown and increase the risk of edge tear. Chill roll surface temperature is maintained between 15 °C and 25 °C for standard gloss and heat-seal performance. Higher chill roll temperatures up to 35 °C are used only when adhesion to low-energy substrates becomes the limiting variable.
| Property | Nominal value | Test method |
|---|---|---|
| Melt index | 2.3 g/10 min | ASTM D1238 |
| Density | 0.920 g/cm³ | ASTM D792 |
| Peak melting temperature | 124 °C | ASTM D3418 |
| Vicat softening temperature | 105 °C | ASTM D1525 |
Compared with high-pressure LDPE of similar melt index, DOWLEX 2645 has a narrower molecular weight distribution and lower long-chain branching. As a result, the melt exhibits lower melt strength and less extension thickening. On extrusion coating lines, this difference is observed as higher neck-in than LDPE when die width and air gap are held constant. Published numerical neck-in comparisons for DOWLEX 2645 are limited; however, conversion requires an air knife or edge encapsulation system when coating width exceeds 1.6 m. Without edge stabilization, the edge bead can shift and reduce usable web width at line speeds above 150 m/min.
Compared with butene-1 LLDPE of equal 0.920 g/cm³ density and 2.3 g/10 min melt index, the octene-1 backbone of DOWLEX 2645 provides higher machine-direction tear resistance under ASTM D1922-15 and higher puncture energy under ASTM D5748-95 on films of identical thickness. The improvement is greatest at thicknesses below 30 µm, where butene-based copolymers typically show a sharper reduction in dart impact resistance. In sealant layers, the resin shows lower seal initiation than high-density polyethylene; hot-tack data under ASTM F1921-12 are used to set packaging line dwell times and jaw temperatures. Compared with metallocene-catalyzed LLDPE, DOWLEX 2645 has a broader composition distribution and faster shear thinning, which can improve melt stability and reduce screw torque on a 24:1 L/D extruder, but it usually exhibits higher haze and lower low-temperature toughness than single-site grades. The selection of DOWLEX 2645 over an mLLDPE is therefore based on the need for extrusion stability and sealant-layer processability rather than maximum optical clarity.
Under FDA 21 CFR 177.1520(c) 3.1a, polyethylene resins of this class may be used for contact with aqueous, acidic, alcoholic, and fatty foods, provided the finished article meets the extractives limitations in the applicable table and the intended conditions of use A through H. The regulation applies to the finished article, not the resin alone. For European compliance, a migration study under EU Regulation (EU) No 10/2011 must evaluate overall migration at 10 mg/dm² or 60 mg/kg simulant, whichever is higher, using food simulants appropriate to the packaged product. For fatty foods, simulant D2 or olive oil may be replaced with 95% ethanol in certain cases; the final packaging structure, including tie layers and adhesives, must be evaluated. The resin is not generally specified for retort packaging above 121 °C because seal strength retention after thermal processing can decline. If a converter requires extended hot-fill conditions, the sealant layer must be tested under ASTM F88/F88M-21 after processing at the target fill temperature.
Seal initiation for DOWLEX 2645 is typically below 110 °C under ASTM F2029-16 when measured on 50 µm cast film at a dwell time of 0.5 s and pressure of 0.4 N/mm². The hot-tack window is narrower than for ionomers but broader than for high-density laminations. On vertical form-fill-seal lines, the jaw temperature typically starts at 110 °C and is adjusted in 5 °C increments until seal strength exceeds 1.5 N/15 mm. Seal strength measurements under ASTM F88/F88M-21 determine the lower and upper jaw limits for a given film structure, because sealant thickness, backing layer stiffness, and surface contamination all shift the operating window.
At chill roll temperatures below 12 °C, moisture condensation on the cast web can generate surface pitting and reduce gloss. At line speeds above 250 m/min, melt resonance can occur if the melt temperature is below 260 °C or the die gap is above 0.9 mm. The defect appears as alternating thick and thin bands perpendicular to the machine direction. Reducing the die gap to 0.6–0.7 mm and raising the melt temperature to 270–280 °C usually stabilizes the web. The resin should not be blended with polypropylene or high levels of high-density polyethylene in the same melt stream without a tie layer, because the resulting phase separation lowers Elmendorf tear resistance and can cause delamination in coextruded structures. When a broader processing window is required, blending up to 15 wt% LDPE reduces neck-in and improves melt strength without significantly altering seal initiation temperature. At LDPE addition levels above 30 wt%, seal initiation temperature can rise by several degrees and the hot-tack window may narrow; converters should re-verify seal performance according to ASTM F1921-12 and ASTM F2029-16 before releasing the film for packing line use.
When the resin is substituted for butene-1 LLDPE in a sealant layer, the converter should expect lower seal initiation and a broader hot-tack window when the film is tested under ASTM F1921-12. The change also affects the coextrusion temperature profile; a die adapter setting that worked for a butene-based grade may require adjustment in 5 °C increments for DOWLEX 2645 because the solution-produced octene copolymer has a different melting and crystallization pattern. Screw torque can change as well; if the extruder is a 45 mm single-screw with 24:1 L/D, torque is evaluated by recording motor load and backpressure before and after the change. If backpressure rises more than 10% at the same screw speed, the barrel profile should be flushed with a fractional-melt LDPE purge compound and the screen pack checked for accumulated gels. Published data for this specific grade substitution is limited; however, sealant-layer quality is directly affected by the degree of mixing in the feed zone and the amount of low-molecular-weight polymer build-up on the screw root.
Processors attempting to purge DOWLEX 2645 from a cast film extruder should use a fractional-melt HDPE or LDPE purge compound in a 400 kg/h production line operating at 220–240 °C, followed by the next production resin. The purge is complete when die lip deposits disappear and backpressure stabilizes within ±3% of the target value. For long shutdowns, the screw and die should be cleared while still molten; thermally degraded material left in the die can carbonize and require dismantling of the 0.6 mm die lip assembly. The resin is not hygroscopic, but if pellets have been stored outdoors or in unheated warehouses, a hopper dryer at 60 °C for 2 h can prevent splay on humid production days. Because DOWLEX 2645 contains no intentionally added slip or antiblock in its base form, surface coefficient of friction must be managed through masterbatch addition or by using a formulated variant if the application requires specific slip performance. The absence of slip additive prevents uncontrolled wax migration in food-contact films and permits the converter to select an additive package matched to packaging line friction requirements.
