LyondellBasell Icorene 3560 BUE 5909 is introduced as a butene-copolymer linear low-density polyethylene (LLDPE) whose designation places it in the intermediate-density segment of the Icorene portfolio. Nominal melt flow rate is 6.0 g/10 min when determined at 190 °C under a 2.16 kg load in accordance with ISO 1133-1:2022. Nominal density is 0.935 g/cm³ when measured by ISO 1183-1:2019. The BUE suffix is associated in LyondellBasell trade literature with a UV-stabilised additive formulation; the numerical suffix 5909 identifies the specific stabiliser and processing-aid package. Published property values for this exact formulation should be confirmed against the current supplier data sheet, because compliance status and minor additive revisions may vary by manufacturing site. The grade is typically positioned for rotational moulding and injection moulding applications in which stiffness, outdoor weathering, and low-temperature ductility are simultaneous design inputs.

What limits processing latitude for the 3560 BUE 5909 in rotational moulding?

At a melt flow rate of 6.0 g/10 min, the material enters the high-flow range for rotational moulding powders. This flow level lowers melt viscosity during the fusion stage, assists bubble removal, and improves detail reproduction in complex tools. However, the processing window is defined not only by melt flow rate but also by peak internal air temperature. In production-scale rotational moulding, oven setpoints for this density class commonly fall between 260 °C and 320 °C, with the internal air temperature of the mould reaching approximately 180 °C to 200 °C. Wall thickness uniformity becomes unstable when the internal air temperature ramp rate exceeds 10 °C/min in thin-walled steel tools; lower ramp rates of 6 °C/min to 8 °C/min generally produce more uniform fusion and lower scrap rates.

Failure modes observed on rotational moulding lines using this MFR class include incomplete bubble removal below 180 °C, surface oxidation discoloration above 320 °C, and warpage in flat parts caused by excessively rapid cooling. Forced-air cooling followed by water mist or water spray is used to reduce warpage, but cooling rate must be controlled because the linear polymer has a high coefficient of thermal expansion relative to metals and a solidification shrinkage that can exceed 2.0 %. In multi-layer rotational moulding with an HDPE backing layer, interlayer adhesion loss can occur if the first layer cools below approximately 110 °C before the second charge is introduced. Batch-to-batch variation in melt flow rate should be monitored at incoming inspection; a shift of more than 0.5 g/10 min can alter cycle time and wall thickness distribution without any change in oven setpoint.

For injection moulding, the 6.0 g/10 min melt flow rate permits processing at melt temperatures of 190 °C to 230 °C with general-purpose screws of 18:1 to 22:1 L/D. Compared with high-pressure LDPE, the linear molecular structure exhibits lower shear sensitivity, so filling thin-walled tools may require higher injection pressure or faster injection velocity. Clamp force demand should be calculated from the projected area of the tool and the expected cavity pressure, not from melt flow rate alone; the higher modulus of 0.935 g/cm³ LLDPE relative to low-density PE can increase injection pressure requirements. Mould temperatures between 20 °C and 40 °C are adequate for most closures, bins, and technical mouldings.

When outdoor exposure, chemical contact, and low-temperature ductility are simultaneous design inputs

The density of 0.935 g/cm³ shifts performance away from flexible LLDPE film grades toward semi-structural mouldings. Typical mechanical values reported for high-flow LLDPE in this density band include tensile yield stress in the range 11 MPa to 14 MPa by ISO 527-2:2012, elongation at break above 800 %, flexural modulus near 350 MPa by ISO 178:2019, and Shore D hardness of 52 to 56 by ISO 868:2003. Vicat softening temperature is typically near 95 °C when determined by ISO 306/A50:2021. These values support use in water tanks, outdoor storage bins, playground components, agricultural hoppers, and material-handling liners. The UV-stabiliser package is intended for multi-year outdoor exposure, but retained elongation at break depends on wall thickness, orientation, and accumulated UV dose. Accelerated weathering by ISO 4892-2:2013 is a comparative screening method, not a direct service-life prediction. Published data for the 5909 additive package under prolonged marine or high-altitude UV exposure is limited.

Chemical resistance follows the general pattern of semi-crystalline polyethylene. The material resists water, aqueous salt solutions, many dilute acids, and many alkalis at ambient temperature. Contact with strong oxidising acids, chlorinated solvents, and aromatic hydrocarbons causes softening and stress cracking. Resistance should be evaluated using ASTM D543-21 under the actual chemical concentration and service temperature. Stress-cracking resistance of LLDPE in this density range is higher than that of HDPE when tested by ASTM D1693-21, but the improvement is not unlimited; continuous load, processing-induced orientation, and concentrated detergent solutions can reduce time to failure.

Table 1 provides a representative comparative profile for the Icorene 3560 BUE 5909 against generic butene-copolymer LLDPE and a higher-density HDPE grade. The values are drawn from typical public literature for the classes and are intended for nominal comparison, not as a contractual specification.

The comparison clarifies the main differentiation from other products. Against high-pressure LDPE, the Icorene 3560 BUE 5909 has a linear backbone and short-chain branches from butene comonomer, producing higher tensile strength, flexural modulus, and puncture resistance at equivalent density. Against HDPE, the lower density reduces stiffness and heat resistance but improves low-temperature impact, environmental stress-crack resistance, and ease of processing at lower pressures. Against a lower-density butene LLDPE, the 0.935 g/cm³ density increases modulus and surface hardness while retaining adequate impact for many moulded parts. Compared with octene-copolymer LLDPE of comparable density and melt flow rate, the butene system may show lower dart impact and tear resistance because the longer short-chain branches in octene grades are more effective in tie-molecule generation; however, butene grades commonly offer lower cost and readier availability in rotational moulding powder forms.

When compared with metallocene-catalysed LLDPE of similar density and MFR, the molecular weight distribution and comonomer distribution of a conventional Ziegler-Natta Icorene grade may be broader. Broader distribution can improve processability and reduce extrusion pressure, but it can also lower notched impact and puncture resistance relative to a substantially linear metallocene grade of the same density. The selection between these classes should be based on whether processing economics or maximum low-temperature toughness is the controlling design variable.

Regulatory status, chemical resistance, and operational boundaries

Food-contact suitability is grade-specific and depends on the exact additive package, migration limits, and end-use conditions. Olefin polymers in this class may be evaluated under FDA 21 CFR 177.1520 and under EU Regulation 10/2011 with an overall migration limit of 10 mg/dm². For the UV-stabilised BUE 5909 formulation, specific migration testing of the stabiliser components may be required for fatty food simulants. Table 2 summarises typical compliance references applicable to LLDPE grades of this type. Verification against the current technical data sheet is required before a final material approval.

Pre-drying is not normally required for rotational moulding powder or pellets. However, if the resin is stored at relative humidity above 60 % and surface condensation is visible, drying at 80 °C for 1 h to 2 h in a desiccant dryer may reduce surface defects. Melt temperatures above 320 °C should be avoided because thermo-oxidative degradation produces discoloration and a measurable loss of elongation at break. Contact with copper and copper alloys during hot processing should be avoided; copper ions accelerate oxidative degradation of polyethylene. The UV-stabiliser package is not a substitute for carbon black in long-service outdoor applications. Black formulations or higher stabiliser loadings may be required for service beyond 10 years in regions with high annual UV dose.