LyondellBasell Icorene 3560 BUE 5119 is a linear low-density polyethylene grade within the Icorene portfolio. The resin is based on a butene comonomer system; the BUE suffix identifies the comonomer and additive configuration, and the 5119 designation identifies the specific stabilized or colour version within the product family. In industrial practice, the grade is used for rotationally moulded and injection-moulded articles where a balance of stiffness, low-temperature ductility, and slow crack growth resistance is required. Under ISO 1043-1:2011, the material can be classified as PE-LLD. Under ASTM D4976-12a, the product falls within the linear low-density to medium-density classification band depending on the exact lot density. For rotational moulding, the material is typically supplied as a free-flowing powder with a nominal top size below 600 µm, although the actual particle-size distribution, bulk density, and dry-flow properties are lot-specific and must be verified against the certificate of analysis.

How does the butene short-chain branch distribution affect sintering and crystallization?

The butene comonomer in Icorene 3560 BUE 5119 introduces short-chain branches that limit lamellar thickness during crystallization. This molecular structure reduces density relative to a high-density polyethylene homopolymer and increases the fraction of amorphous phase that contributes to low-speed ductility and stress-crack resistance. In rotational moulding, the melt experiences near-zero applied shear, so the molecular weight distribution and temperature-dependent melt viscosity control the sintering of individual powder particles. Published representative data for the grade indicate a melt mass-flow rate of 5.5 g/10 min when tested under ISO 1133-1:2022 at 190 °C and 2.16 kg. That flow parameter provides sufficient coalescence for medium-wall sections while limiting gross melt sag in nominal wall thicknesses up to approximately 12 mm.

Sintering proceeds through particle contact, neck growth, densification, and bubble dissolution. For a viscous-coalescence mechanism, neck growth in a polyethylene powder can be approximated by a Frenkel-type relationship in which the neck radius increases with surface tension and time and decreases with viscosity and particle radius. At 190 °C, a typical polyethylene surface tension is in the range of 25–30 mN/m. With a mean particle radius near 100 µm and an apparent melt viscosity in the 10³–10⁴ Pa·s range, particle coalescence under zero shear proceeds rapidly once the melt temperature is reached. The densification stage is slower because trapped gases must diffuse through the melt to an outer surface or into solution. A peak internal air temperature of 190–210 °C is therefore specified for rotational moulding of this grade. Peak internal air temperature below 180 °C can leave residual voids in thick bosses and around metal inserts because bubble collapse is incomplete when the melt viscosity remains above the coalescence threshold.

Cooling rate after densification controls crystal size, density, warpage, and modulus. Rapid cooling of the outer surface against the mould wall produces a finer crystalline structure and lower shrinkage differential than slow air cooling, but it can also introduce thermal residual stress in thick sections. Slow cooling of rotationally moulded parts typically lowers the effective flexural modulus by up to 10–15 % compared with fast-cooled injection-moulded plaques tested under ISO 178:2019. The processor must therefore avoid using injection-moulded property data as a direct predictor of rotationally moulded part performance.

Specification data and controlled test environment

The following table summarizes representative values from technical literature for Icorene 3560 BUE 5119 and the associated normative test conditions. These values are not batch release limits; they are indicative values obtained from compressed or injection-moulded test specimens. Lot-specific certificates should govern incoming inspection.

Melt rheology, density, and ESCR should not be interpreted as single absolute values. Processing history, specimen preparation temperature, cooling rate, and sample thickness shift the measured response. For example, density measurements under ISO 1183-1:2019 are highly sensitive to thermal conditioning; a slowly cooled rotationally moulded wall can exhibit slightly lower density than a rapidly cooled laboratory plaque because of differences in crystallinity. Similarly, the ESCR value obtained under ASTM D1693 condition B is a time-to-rupture under constant strain and is strongly influenced by notch quality, moulded-in stress, and Igepal concentration. Incoming powder dust, agglomerates, or moisture contamination should be controlled before moulding because polyethylene powder at relative humidity above 70 % can retain surface moisture that produces pinholing during oven heating.

Industrial rotational moulding lines processing Icorene 3560 BUE 5119 typically set oven temperatures between 280 °C and 320 °C. The mould surface temperature remains below the oven setpoint because of the heat-transfer lag of steel or aluminium shells. On a 3.0 m four-station carousel machine with a 6 mm wall steel mould, a 10 kg charge can require 18–24 min of heating and 20–30 min of cooling; however, these values are geometry-dependent and are not transferable across mould designs without thermocouple verification. A common production failure signature is pinhole clustering at sharp radii and parting-line weld regions, which occurs when peak internal air temperature is reached before the inner surface has fully densified. If oven temperature is excessive, the outer melt skin seals prematurely and traps decomposition gases or residual air. Powder bulk density and dry-flow behavior affect the wall-thickness distribution in tall or asymmetric parts. Pre-drying at 60–70 °C for 1–2 h is applied when storage relative humidity exceeds 70 %, using a desiccant dryer or equivalent hot-air system. Overdrying above 80 °C can reduce powder flow and increase static build-up on conveying surfaces.

When metallocene or hexene grades become the superior selection

Compared with a high-pressure low-density polyethylene of similar melt-flow rate, Icorene 3560 BUE 5119 provides higher tensile yield and flexural modulus because of its linear backbone and controlled short-chain branching. The improved stiffness is coupled with higher slow crack growth resistance in most low-temperature service conditions. However, its low-shear melt strength is lower than that of a branched LDPE, which can produce greater melt sag in very thick or wide rotational moulding sections. In such cases, a branching-modified or higher-viscosity grade is required.

Compared with octene-based and metallocene-catalysed linear low-density polyethylenes, the butene-based 3560 grade generally exhibits broader short-chain branch distribution and less regular branch spacing. This structural difference reduces slow crack growth resistance at identical density when measured under ASTM D1693 condition C or ISO 16770:2019. Therefore, when an application requires full-notch creep time above 1000 h under ISO 16770:2019 or condition C ESCR beyond 5000 h, an octene-based or metallocene LLDPE should be evaluated instead. The 3560 BUE 5119 grade can still be preferred in conventional rotational moulding equipment because its broader processing window and lower shear sensitivity support more uniform wall thickness in complex tools.

For outdoor tanks and industrial containers, the BUE stabilization package provides light and UV protection. Weathering resistance should be specified and validated under ISO 4892-2:2013, cycle 1A or 1B, with acceptance criteria for colour change, loss of elongation at break, and surface cracking. Published data for this specific 5119 version can be limited when long-term colour shift below Delta E <3 is required; converters must obtain outdoor exposure or xenon-arc data from the technical service group before quoting such limits. The grade should not be placed in continuous service above 60 °C under high mechanical load without a creep evaluation under ISO 899-1:2017. Direct contact with strong oxidizing acids, aromatic solvents, or high-pressure hydrocarbon environments at elevated temperature should be avoided unless supported by chemical resistance testing. Regrind addition is possible in rotational moulding at controlled levels, but each 10 % increase in regrind can reduce particle size consistency and increase the risk of surface porosity if the regrind contains oxidized material from previous cycles. The processor should therefore establish a controlled regrind protocol with incoming melt-flow and density checks after every 50 cycles of reclaimed material use.

Regulatory conformance must be confirmed from the product safety data sheet and product compliance declaration. REACH obligations apply under EC 1907/2006; restricted substances are managed under EC 1907/2006 Annex XVII and, where applicable, RoHS Directive 2011/65/EU. Food-contact status is use-specific and must be validated by the converter for the finished article under relevant migration testing; classification under 21 CFR 177.1520 or European food-contact legislation is not an automatic property of the raw material and must be confirmed for the exact grade, batch, and processing conditions. The same limitation applies to medical and potable-water applications, where extraction and migration behaviour are governed by the complete processing and sterilization history rather than by resin designation alone.