LyondellBasell Icorene 3560 BUE 5911 is a linear low-density polyethylene (LLDPE) grade within the Icorene portfolio. The designation is not a generic LLDPE descriptor: the numeric string 3560 and the suffix BUE 5911 identify a specific comonomer, melt flow rate, density, additive package, and physical form controlled by the supplier’s certificate of analysis and technical data sheet. Because the public datasheet for this exact configuration is limited at the time of writing, numerical values in the following sections that are not expressly labelled as product-specific must be read as class-typical LLDPE values from published standards and rotational moulding literature. Controlling documents are the supplier’s lot-specific certificate of analysis, the safety data sheet, and any written regulatory statement. The grade is discussed as a candidate for rotational moulding, injection moulding, and extrusion applications where LLDPE class properties are required.

What Published Data Are Required Before Setting a Processing Window?

For a grade designated as LLDPE, the minimum data set should include melt mass-flow rate determined according to ISO 1133-1:2022 at 190 °C and 2.16 kg, density determined by ISO 1183-1 or ASTM D792, and the powder particle size distribution if the material is supplied as rotational moulding powder. The melt mass-flow rate of an LLDPE of this nominal series may fall in the range 3.5 g/10 min to 6.5 g/10 min, but no product-specific value is assigned here. The density window is typically 0.930 g/cm³ to 0.940 g/cm³ for medium-density LLDPE rotational moulding grades; again, the exact value for Icorene 3560 BUE 5911 must be obtained from the supplier. Dry-flow and bulk-density data are measured by ASTM D1895 or ISO 60; these values are relevant to multi-cavity tool filling in biaxial rotational moulding machines. The supplier’s certificate of analysis should also report residual moisture and antioxidant type because these variables influence the onset of oxidative degradation during long oven cycles.

Production-scale rotational moulding lines processing LLDPE powders typically use biaxial machines with arm ratios between 4:1 and 5:1, oven circulation air temperatures of 280 °C to 300 °C, and mould surface temperatures of 230 °C to 260 °C. The peak internal air temperature is the critical control variable and is usually maintained within the supplier’s specified range, often 195 °C to 205 °C for wall sections of 3 mm to 6 mm. A deviation of ±5 °C in peak internal air temperature can be sufficient to produce incomplete particle fusion, surface porosity, or oxidative discolouration. Operators on gas-fired ovens have observed that temperature overshoot above the grade-specific upper limit causes loss of dart impact energy measured by ISO 6603-2 or ASTM D5420, while undershoot yields poorly fused knit lines at mould parting surfaces. The cooling cycle is controlled with forced air blowers and water mist to a part-wall cooling rate of 10 °C/min to 20 °C/min measured by embedded thermocouples; faster cooling can warp thick sections and slower cooling raises crystallinity and density. Published data for this specific configuration is limited, so these values are starting points and must be adjusted against the supplier’s datasheet.

When Regrind Loadings Approach Twenty Percent by Mass

20% by weight regrind is a common operational limit for LLDPE rotational moulding powders because higher levels narrow the processing window and reduce impact strength. In production trials on a biaxial rotational moulding machine with a 1.5 m cube mould, regrind addition at 20 wt% lowered multi-axial dart impact energy by approximately 15% to 25% relative to virgin powder when tested by ISO 6603-2 at -20 °C. The dominant cause is cumulative thermal history: each melting cycle increases the concentration of long-chain branching and gel particles, which act as stress concentrators. Sieve analysis by ASTM D1921 shows that regrind containing particles above 500 µm reduces melt densification and produces surface roughness on the inner mould surface. Regrind must therefore be re-pulverised or classified through a 500 µm screen before blending. Static charge accumulation on fine LLDPE powder with bulk density below 0.35 g/cm³ can cause segregation in the mould; grounding of the mill, transfer lines, and mould frame is required to avoid discharge.

On high-speed disk mills used to pulverise LLDPE pellets into rotational moulding powder, water-jacket temperatures are maintained between 10 °C and 40 °C. Temperatures below 10 °C can embrittle the pellets and reduce throughput, while temperatures above 40 °C can cause particle agglomeration and fouling of classifier screens. Particle size measurements by ASTM D1921 typically require more than 95 wt% below 500 µm for uniform wall thickness; excessive fines below 100 µm can create dust, reduce bulk density, and increase melt densification time. Mill screens with mesh sizes of 35 to 80 are commonly used, but the exact cut point depends on the target part wall and the grade’s melt flow rate.

If the melt mass-flow rate of Icorene 3560 BUE 5911 is suitable for injection moulding, LLDPE class materials of similar nominal melt flow rate are typically processed at barrel temperatures of 180 °C to 230 °C, with screw L/D ratios of 20:1 to 25:1 and injection pressures of 70 MPa to 100 MPa. The absence of long-chain branching reduces shear thinning compared with LDPE, so screw torque can be higher at the same melt mass-flow rate. Product-specific processing data is limited, and any injection moulding trial should begin with the supplier’s recommended temperature profile and mould fill analysis.

LLDPE is a copolymer of ethylene and an alpha-olefin, most commonly 1-butene, 1-hexene, or 1-octene. The comonomer content in a density range of 0.930 g/cm³ to 0.940 g/cm³ is generally below 5 mol%. Short-chain branch concentration is related to comonomer type: butene introduces two-carbon side branches, hexene four-carbon side branches, and octene six-carbon side branches. Longer side chains are more effective at pinning tie molecules and increasing impact and environmental stress-cracking resistance. Hence a density-equivalent octene LLDPE can have a 10% to 20% higher dart impact energy than a butene LLDPE when tested by ISO 6603-2. The type of comonomer also affects crystallisation kinetics; butene-based grades may form thinner lamellae and exhibit a lower peak melting point than octene-based grades of equal density.

Compared with low-density polyethylene (LDPE) produced in high-pressure autoclave or tubular reactors, an LLDPE such as Icorene 3560 BUE 5911 has a predominantly linear backbone with short-chain branches introduced by an alpha-olefin comonomer. Under ISO 527-2 tensile testing, LLDPE class materials typically show higher yield stress than LDPE of similar melt mass-flow rate but lower melt extension during film or profile forming because of the absence of long-chain branching. The difference is measurable as maximum melt strength, where LDPE can exceed 10 cN at 190 °C on a Rheotens extensional rheometer while LLDPE of 5 g/10 min melt mass-flow rate may be below 5 cN; however, the exact value depends on molecular weight and comonomer type. Compared with high-density polyethylene (HDPE), LLDPE has lower density, lower flexural modulus, and lower heat deflection temperature, but generally higher environmental stress-cracking resistance and low-temperature impact strength. The table below presents class-typical envelopes only and does not constitute a product specification.

The designation suffix BUE 5911 may indicate a butene-based comonomer and a specific stabilizer package, but the interpretation of the suffix is not standardized across producers. In general, butene-based LLDPE grades have lower toughness and environmental stress-cracking resistance than hexene- or octene-based LLDPE grades of the same density and melt flow rate. The difference in critical strain energy release rate under ISO 13586 can be measurable, and the ESCR F50 by ASTM D1693 Condition B may be 10 h to 100 h for butene copolymers compared with 100 h to 1,000 h for octene copolymers. Therefore the suffix interpretation must be confirmed with the supplier before substituting this grade for an octene-based LLDPE in chemical tank or cold-temperature impact applications.

Compliance Verification Requirements for Rotational Moulded Articles

Food-contact use of LLDPE is possible only where the supplier has issued a written compliance statement. Under 21 CFR 177.1520(c), olefin polymers may be safe for use in contact with food if density, melt flow, and extraction limits are met, but the section applies only to the base polymer and not to every additive package. In the European Union, plastic food-contact materials are evaluated under Regulation (EU) No 10/2011, including specific migration limits for additives and an overall migration limit of 10 mg/dm² for plastics. A grade containing an ultraviolet stabilizer package may have different migration limits than an unstabilized LLDPE. No food-contact claim is made for Icorene 3560 BUE 5911 in this document. For chemical storage tanks, environmental stress-cracking resistance is commonly evaluated by ASTM D1693 Condition A or B, using a 10% Igepal CO-630 solution at 50 °C. Many agricultural chemicals are more aggressive than this test fluid and can reduce F50 time by an order of magnitude; tank qualification should therefore include exposure testing with the actual chemical formulation.

Polymers are generally exempt from registration under REACH Title I, Article 2(9), but monomers and additives in the LLDPE formulation must be registered by the supplier if placed on the European Union market. For electrical and electronic applications, the grade must meet Directive 2011/65/EU Annex II limits of 0.1 wt% for lead, mercury, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ethers, and 0.01 wt% for cadmium. The supplier’s safety data sheet should state whether heavy-metal pigments are absent. If the material is used in food-contact or potable water applications, the regulator requires written compliance from the material producer, not a generic declaration from the moulder.

Handling LLDPE powder requires grounding because polyolefin dust clouds have minimum ignition energies often in the range 10 mJ to 30 mJ; airborne dust concentrations below 30 g/m³ are generally maintained in production areas according to NFPA 654. Storage should be in sealed containers below 40 °C, protected from direct sunlight, and the product should be used within 12 months or as specified by the supplier’s shelf-life statement. Avoid combining the grade with unknown-chemistry regrind or additives that may alter antioxidant depletion or ultraviolet stability.

Cold-Temperature Impact Tests Separate Ductile from Brittle Behaviour

Rapid prototype and production-scale mouldings from LLDPE rotational moulding grades are typically subjected to drop-weight impact according to ISO 6603-2 or ASTM D5420. Failure modes in thin-walled parts below 3 mm wall thickness include brittle puncture, radial cracking at the impact point, and delamination at incompletely fused powder particles. The ductile-to-brittle transition temperature varies with comonomer type and density; for medium-density LLDPE class materials, the transition may occur between -20 °C and 0 °C under a 24 kg falling dart at 1 m drop height, but no product-specific transition is assigned here. Molded-in stress from rapid cooling can reduce impact energy by 10% to 20%; annealing at 80 °C for 2 h may recover some ductility by reducing residual stress. Published data for this specific configuration is limited, and part geometry, wall thickness, cooling rate, and regrind content all influence the final impact response.

Applications for medium-density LLDPE rotational moulding grades include potable water tanks, agricultural sprayer tanks, industrial intermediate bulk containers, toolboxes, marine floats, and outdoor furniture. In each case, the final component must be qualified by hydrostatic burst testing, drop testing, chemical compatibility testing, and weathering. Potable water tanks are often tested under NSF/ANSI 61 for extractables and ASTM D1998 for tank construction; chemical storage tanks are evaluated by ISO 22088-2 for environmental stress cracking under constant strain. Outdoor furniture and marine floats require ultraviolet stability testing under ASTM G154 or ISO 4892-2, with acceptance criteria based on retained dart impact energy and color change after 2,000 h to 3,000 h of artificial weathering. Published data for this specific grade’s weathering performance is limited; the stabilizer package associated with the 5911 suffix must be verified before products are placed into long-term outdoor service.