| HS Code | 861743 |
| Density | 0.935 g/cm³ |
| Melt Flow Index 190 C 2 16kg | 4.0 g/10min |
| Tensile Strength At Yield | 16.0 MPa |
| Elongation At Break | >500% |
| Flexural Modulus | 540 MPa |
| Shore D Hardness | 55 |
| Vicat Softening Point | 120 °C |
| Melting Point | 124 °C |
| Brittleness Temperature | -80 °C |
| Environmental Stress Crack Resistance | >1000 hrs |
As an accredited LOOTE LLDPE UR644 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | LOOTE LLDPE UR644 is supplied in 25 kg polyethylene-lined kraft bags, ensuring safe handling, moisture protection, and contamination-free storage. |
| Container Loading (20′ FCL) | 20′ FCL: LOOTE LLDPE UR644 loaded in 25 kg bags, approximately 20 metric tons per container, dry, secured, contamination-free. |
| Shipping | LOOTE LLDPE UR644 is shipped as non-hazardous resin pellets in sealed bags, bulk bags, or railcars. It should be transported in clean, dry containers to prevent contamination and moisture absorption. Avoid excessive heat and direct sunlight during transit. Handle with care to maintain product integrity and ease of unloading. |
| Storage | Store LOOTE LLDPE UR644 in a cool, dry, well-ventilated area, away from direct sunlight, heat sources, and open flames. Keep bags sealed and on pallets to prevent moisture, dust, or contamination. Avoid contact with strong oxidizers and sharp objects. Maintain stable temperatures and good warehouse hygiene to preserve resin quality. |
| Shelf Life | Shelf life is typically one year from production date when stored in original packaging in a cool, dry, well-ventilated area. |
The design basis for LLDPE UR644 in aggressive aqueous chemical containment is ASTM D1998-21, which governs polyethylene upright storage tanks and links wall-thickness allowances to specific gravity and hydrostatic head. Rotomolded shells produced from UR644 are characterized by a density of 0.934 g/cm³ under ASTM D792 and a melt flow rate of 4.0 g/10 min at 190°C/2.16 kg in ISO 1133-1:2022; the tensile yield of 17.0 MPa at 50 mm/min under ASTM D638-14 and F50 environmental stress crack resistance above 1000 h under ASTM D1693-15 support the grade’s use where sodium hydroxide, sodium hypochlorite, or dilute mineral acids are stored at ambient temperature. Formulation control for corrosive service adds 0.3–0.8 wt% HALS stabilizer via a 3–5 wt% UV/antioxidant masterbatch and 0.05–0.12 wt% process antioxidant, with no mineral filler or antistatic additive because conductive carbon residues reduce weld-line integrity in multi-axis rotations. Production equipment includes carousel or shuttle rotational molding machines with a mold plate maximum swing diameter of 2.0–2.5 m, pulverized powder D50 of 250–300 µm, and a mold rotation ratio of 4:1 primary to secondary axis. Oven setpoint is 280–310°C; the internal air temperature target of 190–220°C is held for 18–25 min depending on wall thickness, with an internal air pressure of 0.03–0.06 MPa maintained to suppress peel-off and surface pitting. Demolding occurs only after forced-air cooling below 70°C, since earlier ejection creates sink marks at insert bosses. Continuous service above 50°C under mechanical load or immersion in concentrated sulfuric acid above 60°C is outside the validated operation boundary. Terminal products include 500–10,000 L vertical cylindrical tanks, chemical dosing tanks, scrubber sumps, and secondary containment inserts.
| Compliance parameter | Standard or test method | Relevant specification |
|---|---|---|
| Upright tank shell material | ASTM D1998-21 | wall thickness linked to specific gravity and hydrostatic head |
| Melt flow rate | ISO 1133-1:2022 | 4.0 g/10 min at 190°C/2.16 kg |
| Density | ASTM D792 | 0.934 g/cm³ |
| Tensile yield | ASTM D638-14 | 17.0 MPa at 50 mm/min |
| Environmental stress crack resistance | ASTM D1693-15 | F50 above 1000 h |
| EU chemical registration | REACH 1907/2006 | Annex XVII restrictions applicable to finished article |
In drip-irrigation reservoir production, the same rotomolding conversion route is modified to prioritize long-term outdoor weathering retention over acidic chemical resistance; the formulation typically contains 3.5–4.5 wt% UV-stabilized carbon black masterbatch to achieve 2.2–2.5 wt% final carbon black loading, 0.10–0.15 wt% phenolic antioxidant, and 0.05–0.10 wt% zinc stearate as acid scavenger. Finished tanks are evaluated under ISO 11469 for marking and ASTM D638-14 for tensile yield retention after 2000 h xenon-arc exposure under ASTM D2565-21, while FDA 21 CFR 177.1520 is referenced only where potable-water contact is claimed in municipal or horticultural installations. The rotomolding cycle uses single-station shuttle machines with a 4.5:1 rotation ratio and oven setpoints of 290–300°C; production-scale failure records show that coarse powder fractions above 600 µm from poorly milled material create air inclusions at radii below 12 mm, so the powder is specified with 85–90 percent passing 35 mesh. Powder storage is controlled below 60% relative humidity; at higher moisture pickup, pre-drying at 80°C for 2 h is required to prevent steam pinholes. Cooling is staged through the polyethylene crystallization plateau at 2–3°C/min until the mold surface reaches 65°C, which controls panel distortion on flat tank sides. Terminal products include 1,000–20,000 L irrigation reservoirs, fertigation mixing tanks, and settling basins.
Roto-moulded kayak hulls use UR644 where impact toughness in water is the central acceptance criterion. The material is tested under ASTM D638-14 tensile yield at 17.0 MPa, ASTM D790-17 flexural modulus, and low-temperature impact under ISO 179-1/1eA; finished boats may require CE marking under Directive 2013/53/EU for EU market access, but material qualification for hulls is generally governed by the buyer’s in-house cyclic loading protocol rather than a single ISO product standard. The powder formulation adds 1.0–3.0 wt% weather-stable pigment concentrate, 0.3–0.6 wt% HALS, and 0.05–0.10 wt% antioxidant; pigment concentrates with phthalocyanine blue or carbon black are preferred because low-molecular-weight organic pigments migrate during 285–300°C oven dwell and generate bubble defects in the outer skin. Rock-and-roll machines with foam-filled aluminum molds apply a 4:1 rotation ratio, and the internal air temperature is held at 195–205°C for a 4–6 mm wall. The production bottleneck is cooling warpage: the hull is cooled in a water-spray cabinet at 2.5–4.0°C/min to 55°C, then held in a jig for 30–60 min to control asymmetry. Terminal products include sit-on-top kayaks, canoe hulls, paddleboard outer shells, and small craft accessory hulls.
On temporary traffic management lines, water-filled barricade bodies and delineator bases are rotomolded from UR644 because the grade offers the necessary low-temperature drop impact retention and avoids brittle fracture at -20°C service temperatures when the wall contains no hygroscopic filler. The formulation adds 1.5–2.5 wt% UV-stabilized orange or white masterbatch, 0.20–0.30 wt% antioxidant, and up to 5 wt% plant-regrind reuse only after melt flow rate and ESCR conformance is demonstrated on the batch blend. Material compliance is anchored to ASTM D638-14 tensile properties, ASTM D2565-21 xenon-arc retention of color after 1500 h, and ASTM D1693-15 F50 ESCR above 800 h for regrind blends; full barrier crashworthiness is jurisdiction-specific and not claimed solely from material data. Rotational molding parameters include 5–8 mm wall thickness, oven setpoint 285–300°C, internal air temperature 190–210°C, and forced-air cooling to 60°C before demold. Warpage at the fill-cap face is controlled by maintaining 0.03–0.05 MPa internal air pressure through the cooling phase, preventing the outside skin from separating from the mold surface. Terminal products include 1,500–2,200 mm water-filled barricade bodies, sign bases, and delineator bodies.
Cold chain insulated containers produced from UR644 rely on a sequential rotomolding operation that creates a hollow double-wall cavity later filled with 40–50 kg/m³ polyurethane foam. The inner food-contact layer is specified from 100% virgin resin to meet FDA 21 CFR 177.1520 and EC 1935/2004 requirements; the outer structural skin may contain 10–15 wt% regrind when the regrind is from the same grade and the melt flow rate shift does not exceed 0.3 g/10 min under ISO 1133-1:2022. Formulation loads 2.0–3.0 wt% food-approved blue or white masterbatch and 0.15–0.25 wt% antioxidant into both layers; no slip or antistatic additive is used in the inner layer due to migration risk. The first skin is rotomolded at an internal air temperature of 195–210°C to a wall thickness of 4.0 mm, the mold is cooled to 70°C, and the second skin is then processed; the cavity is filled with rigid polyurethane foam under 0.05–0.08 MPa pressure to avoid collapsing the outer walls. The main field failure is foam expansion pressure creating local bulges when demolded below 45°C, so cooling is controlled at 1.5–2.5°C/min through the solidification range. Terminal products include 300–600 L insulated fish tubs, pharmaceutical cold-chain containers, and seafood export boxes.
Municipal waste containers conforming to EN 840-1:2020 are rotomolded with 2.0 wt% UV-stabilized masterbatch and 0.10 wt% antioxidant; the cycle uses an internal air temperature of 190–210°C and demold below 65°C on carousel machines. Published data for this specific configuration is limited beyond standard ESCR testing under ASTM D1693-15, so regrind rates above 10 wt% are not specified without batch-specific F50 verification. Terminal products include 120–360 L two-wheeled collection carts and 1,100 L communal bins.
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LOOTE LLDPE UR644 is introduced as a linear low-density polyethylene copolymer supplied for rotational molding and thick-section extrusion. The UR644 suffix is a producer-specific grade identifier and is not defined as a classification under ISO 1872-1. The certificate of analysis remains the controlling document for any numerical property. The resin is typically delivered as a free-flowing rotomolding powder with a nominal top particle size near 500 µm, sometimes described as 35-mesh powder. The density of this product segment is generally bracketed between 0.934 g/cm³ and 0.940 g/cm³ when measured by ISO 1183-1, and the melt flow rate is expected between 3.0 g/10 min and 6.0 g/10 min at 190 °C and 2.16 kg under ISO 1133-1:2022. These values place the grade in a fractional-melt, high-toughness envelope that differs from high-flow LLDPE used in thin-wall injection molding, where melt flow rates commonly exceed 20 g/10 min. Because producer datasheets for LOOTE LLDPE UR644 have not been harmonized across all regions, fixed values should be verified against the lot certificate before tooling or process parameters are finalized.
The principal structural feature used to differentiate this grade from conventional butene-copolymer LLDPE is the short-chain branching distribution. In butene-copolymer LLDPE, the ethyl side group is relatively short, and the crystal lamellae retain a higher degree of order at a given density. Longer comonomer units, such as 1-hexene or 1-octene, generate more effective tie-molecule populations, which lowers the brittle transition temperature and increases resistance to slow crack growth. The relevant test methods are ISO 179-1 for notched pendulum impact and ASTM D1693 for environmental stress crack resistance. Published data for the specific UR644 configuration are limited; however, polyethylenes in this density and comonomer family commonly shift the ductile-to-brittle transition below -40 °C when specimens are prepared from compression-molded sheet and tested at 1.5 m/s striker velocity. The improvement is not linear with comonomer content, and secondary recrystallization during slow cooling can partially erase the tie-molecule advantage at higher comonomer fractions.
In thick rotomolded tanks, failure mode is often controlled by corner cracking rather than uniform tensile yield. The higher tie-molecule fraction in the UR644 architecture changes the crack initiation threshold under biaxial stress. When a tank is impacted at -20 °C, a butene-copolymer LLDPE of the same nominal density may develop a brittle crack from the inner surface because a lower tie-molecule concentration allows crack propagation along lamellar boundaries. The same geometry molded from a hexene- or octene-modified resin of the UR644 type typically exhibits a stress-whitened ductile hinge or puncture without radial fracture. This distinction can be quantified by the instrumented falling-weight test ASTM D3763 and by the biaxial impact test ISO 6603-2. The total energy at maximum load is commonly used as a specification limit. Molded parts should be conditioned for at least 40 h at 23 °C and 50% relative humidity before testing because LLDPE impact properties are sensitive to physical aging, especially near the glass transition of the amorphous phase.
At the melt-rheology level, the molecular weight distribution is broader than that of a metallocene LLDPE, which has consequences for sintering and bubble removal. Dynamic oscillatory shear data generated according to ISO 6721-10 on a parallel-plate rheometer show that hexene-copolymer LLDPE of this melt flow range retains a higher crossover modulus and longer terminal relaxation time than metallocene grades of equal melt index. This produces better mold-surface coating at low shear but slower bubble dissolution at the same peak internal air temperature. The recommended processing window therefore includes a slightly higher peak internal air temperature or a longer dwell time than would be required for a narrow-distribution metallocene rotomolding resin. Published data for this specific configuration are limited, so oven trials with internal air temperature profiling are required for part validation.
On production-scale shuttle and carousel rotomolding machines, LOOTE LLDPE UR644 is normally processed using a biaxial rotational ratio of 4:1. Mold surface temperatures are monitored with an infrared pyrometer, while internal air temperature is logged with a slip-ring thermocouple inserted through the vent tube. The target peak internal air temperature is generally between 190 °C and 210 °C. Below 180 °C, residual unmelted powder particles can remain at the parting line and around inserts. Above 220 °C, the hindered phenolic stabilizer system begins to be consumed more rapidly, and the notched impact strength of the part can decline even though the outer surface shows no visible oxidation. Wall thicknesses from 3 mm to 12 mm can be produced, but the cooling cycle must be adjusted because crystallization occurs between 110 °C and 120 °C under typical quiescent conditions. Slow cooling through this range increases spherulite size and can raise density while increasing warpage anisotropy.
Powder quality is a defining variable for the UR644 processing behavior. Dry-flow rate is measured by ASTM D1895-96 Method A or ISO 6186, with rotomolding powders generally falling between 25 s and 40 s for a 100 g sample. A sieve residue maximum of 5% on a 500 µm screen is typical for the coarse fraction, while fines below 75 µm are held below 10% to limit dust accumulation in the mold cavity and uneven melt-out. Bulk density measured by ASTM D1895 Method A is commonly between 0.32 g/cm³ and 0.38 g/cm³ for the powder; this range is low enough to allow free flow but high enough to avoid excessive entrainment of air. During mold heating in a forced-air oven set at 280–320 °C, the powder must sinter before full densification. If the oven temperature is too high, the surface can fuse before the interior reaches the target peak internal air temperature, trapping unmelted particles and creating a porous inner layer.
Moisture control is a boundary condition rather than a processing recommendation. Rotomolding powders are usually not pre-dried when stored below 60% relative humidity. Above 60% relative humidity, surface moisture can exceed 0.10 wt% as measured by ISO 15512, and bubble nucleation may increase in the outer skin. A vent tube with an internal diameter of 2–4 mm is used to equalize pressure without allowing the melt to escape. When the mold is cooled with water mist or forced air, the cooling rate through the crystallization plateau should be controlled between 8 °C/min and 15 °C/min. Faster cooling reduces warpage by minimizing differential shrinkage, but it also reduces the degree of crystallinity and can lower short-term stiffness. The balance between cooling rate and part dimensions is more critical for flat panels and large tanks than for small containers.
Mechanical property comparisons for LOOTE LLDPE UR644 should be carried out on compression-molded sheets prepared according to ISO 293 or on rotomolded plaques with documented cooling history. Tensile yield stress is measured by ISO 527-2 on Type 1B specimens at 50 mm/min; the expected envelope for this density family is 15–19 MPa. Elongation at break generally exceeds 700% in the machine direction, though the exact value depends on crystallinity and specimen thickness. Flexural modulus is measured by ISO 178 at 2 mm/min and typically falls between 600 MPa and 800 MPa. This range is below that of a butene-copolymer LLDPE of equal density because the longer comonomer depresses the crystalline fraction. Notched Izod impact at -40 °C under ISO 180/A is sensitive to notch sharpness and is usually reported between 8 kJ/m² and 15 kJ/m². For rotational molding applications involving drop impact or stone impact, the instrumental falling-weight test ASTM D3763 provides a more reliable ranking.
Environmental stress crack resistance is the main property that distinguishes the UR644 type from lower-cost butene-based LLDPE. The standard bent-strip method ASTM D1693 uses 10% Igepal CO-630 at 50 °C and reports the F50 failure time. For hexene-copolymer LLDPE in the density range 0.934–0.940 g/cm³, F50 values often exceed 1000 h, whereas butene-copolymer LLDPE of the same melt flow and density may fall below 100 h under identical conditions. The test is statistical; a minimum of 10 specimens per batch is required because failure times follow a log-normal distribution. The full-notch creep test ISO 16770 is preferred for specifying structural tanks because it applies a constant tensile load and measures the time to brittle fracture at 80 °C in a diluted surfactant solution. A minor increase in density from 0.937 g/cm³ to 0.942 g/cm³ can reduce ESCR by several hundred hours, so density tolerance is a critical lot-by-lot variable.
Chemical resistance data for LOOTE LLDPE UR644 should be generated for each end-use fluid because environmental stress cracking is accelerated by polar organic compounds, especially soaps, alcohols, and surfactants. The grade is generally resistant to aqueous acids and alkalis at ambient temperature, but oxidative chemicals such as concentrated nitric acid or sodium hypochlorite above 60 °C can consume the stabilizer package and degrade molecular weight. Continuous contact with strong swelling solvents such as toluene or xylene is outside the reliable design envelope. In rotomolded tanks for diesel exhaust fluid or agricultural chemical storage, compatibility testing should follow the progression of ISO 175 liquid exposure for dimensional and mass change, followed by ASTM D1693 or ISO 16770 after immersion to detect retained stress-cracking susceptibility.
For food-contact and potable water applications, the grade must be qualified against the end-use jurisdiction. Polyethylene homopolymers and copolymers of this type are addressed in FDA 21 CFR 177.1520 for olefin polymers, provided the density and extractables meet the specified conditions of use. European food-contact compliance is evaluated under EU Regulation 10/2011, with overall migration limits of 10 mg/dm² for food-contact surfaces and specific migration limits for any additives used in the formulation. Potable water contact in North America may require certification to NSF/ANSI 61, while global chemical inventory compliance is documented through REACH and RoHS declarations. The producer’s compliance certificate should identify the exact product grade, manufacturing site, and authorized use; generic statements for “LLDPE” are not sufficient.
| Qualification area | Standard or regulation | Typical data requirement for LOOTE LLDPE UR644 |
|---|---|---|
| Melt mass-flow rate | ISO 1133-1:2022 / ASTM D1238 | 3.0–6.0 g/10 min at 190 °C, 2.16 kg; lot certificate required |
| Density | ISO 1183-1 / ASTM D1505 | 0.934–0.940 g/cm³; lot certificate required |
| Tensile yield stress | ISO 527-2 | 15–19 MPa at 50 mm/min |
| Flexural modulus | ISO 178 | 600–800 MPa at 2 mm/min |
| Notched Izod impact | ISO 180/A | 8–15 kJ/m² at -40 °C |
| Environmental stress crack resistance | ASTM D1693 | F50 > 1000 h in 10% Igepal at 50 °C for qualified hexene-copolymer LLDPE; specific UR644 value to be confirmed |
| Oxidative induction time | ISO 11357-6 | 20–40 min at 200 °C |
| Food contact | FDA 21 CFR 177.1520; EU Regulation 10/2011 | Grade-specific certificate of compliance for end-use conditions |
The values in the table are representative brackets for linear low-density polyethylene rotational molding grades in the UR644 density class. They are not a certificate of analysis. Published data for this specific configuration are limited; for structural parts, a three-lot qualification using the actual rotomolding machine is required before production release.
In comparison with metallocene LLDPE rotational molding grades, LOOTE LLDPE UR644 is expected to show broader molecular weight distribution and stronger shear-thinning at low shear rates, which can improve mold-surface coverage during rotation but reduces the ultimate low-temperature impact of thin-wall parts. Metallocene resins of the same density often provide higher dart impact and lower warpage because their short-chain branching is more uniform, but they can also suffer from melt elasticity that is too low for large flat panels, causing pinholes at the inner surface. Compared with high-density polyethylene rotational molding grades, the UR644 class sacrifices stiffness and heat deflection temperature to gain ESCR and low-temperature ductility. The heat deflection temperature under ISO 75-2 Method B is expected to be below 65 °C, which limits continuous service under structural load above this threshold. Crosslinked polyethylene remains the choice for aggressive chemical storage at elevated temperatures, although it is not mechanically recyclable in the same stream.
Thermal-oxidative stability is evaluated by isothermal OIT and multi-pass extrusion because oven residence time is the most aggressive thermal history for this material. OIT is measured by differential scanning calorimetry under ISO 11357-6, typically at 200 °C in oxygen. A stabilized rotomolding grade of this type usually shows an OIT of at least 20 min to 40 min when tested on the powder or ground part. The OIT value alone does not predict long-term thermal stability at service temperatures below 60 °C, because secondary antioxidant migration and consumption follow different kinetics. Multi-pass extrusion on a co-rotating twin-screw extruder with an L/D 36:1 screw configuration and a strand die is used to simulate repeated processing; the melt flow rate shift after five passes is commonly specified as less than 10% relative to the virgin powder. For thick-wall tanks that are oven-aged at 100 °C for 1000 h in air, tensile elongation retention is a more direct measure of oxidative embrittlement.
Storage of LOOTE LLDPE UR644 should be in a dry, closed system at or below 40 °C, protected from ultraviolet light. Rotational molding powder can retain electrostatic charge after silo transport; a grounded blending hopper is used before mold charging. The material should not be melt-blended with strong oxidizing agents, peroxides, or amine-based antistatic compounds unless the stabilizer package has been reformulated by the producer, because amine chemistries can antagonize the phenolic antioxidant cycle. Pre-drying is required only when the powder has been exposed to relative humidity above 60% for more than 48 h. Drying with desiccant air at 70–80 °C for 2–4 h is sufficient to restore surface moisture below 0.10 wt%. Overdrying at higher temperatures can agglomerate the powder and reduce dry-flow.
In a rotomolded agricultural chemical tank with a nominal wall thickness of 8 mm, the LOOTE LLDPE UR644 grade can be processed on a carousel machine with an oven set point of 290 °C, a mold rotational ratio of 4:1, and a target peak internal air temperature of 200 °C. The demolded part should be conditioned for 24 h at 23 °C before dimensional inspection because post-mold shrinkage continues slowly through the first day. Qualification testing under ISO 6603-2 at -20 °C and ASTM D1693 after surfactant conditioning is then used to confirm the lot’s ductile performance envelope. The final acceptance criteria should always be derived from the actual part and the actual mold, not from the powder’s nominal datasheet values alone.
