LyondellBasell Icorene 3560 BUE 5114 is a linear low density polyethylene (LLDPE) grade supplied in pelletized form within the Icorene high-flow butene-copolymer series. The model designation comprises the base resin code 3560, the formulation suffix BUE, and the recipe code 5114. The BUE segment is generally associated with a UV-stabilized additive package in LyondellBasell’s polyolefin nomenclature, but the complete stabilizer and pigment composition is disclosed only through the supplier’s certificate of analysis and regulatory information letter. The nominal density is 0.934 g/cm³ when measured according to ISO 1183-1:2019, and the melt mass-flow rate is 35 g/10 min when measured at 190°C under a 2.16 kg load according to ISO 1133-1:2022. These two properties situate the grade in the high-flow, upper-density region of the LLDPE spectrum. The density approaches the 0.940 g/cm³ boundary at which polyethylene is reclassified as medium density, producing higher flexural modulus and surface hardness than low-density film grades. The melt flow rate of 35 g/10 min is several times higher than the 0.5–2.0 g/10 min typical of blown-film extrusion LLDPE and above the 10–20 g/10 min range common for general-purpose injection-moulding LLDPE. The high flow reduces injection pressure and permits thin-wall fill, but it lowers average molecular weight and thereby reduces slow crack growth resistance and low-temperature impact relative to lower-MFR grades.

The grade is intended for injection moulding of semi-rigid articles where short cycle times and long flow lengths are more critical than sub-ambient impact or chemical stress crack resistance. Typical application areas include thin-wall packaging lids, overcaps, housewares, inserts, and caps requiring good dimensional stability at moderate service temperatures. It is not suitable for blown film, blow moulding, or rotational moulding because the low melt strength and high melt flow rate create bubble instability, parison sag, and poor sinterability in rotomoulding processes. Published data for this specific configuration in rotomoulding is limited, but the physical constants of the grade already exclude it from the melt flow range typically used for rotomoulding powders, which is commonly 3–6 g/10 min.

Table 1 contains representative values quoted from publicly available supplier literature. The values are nominal and should not be used as acceptance criteria without a lot-specific certificate of analysis. Storage conditions, regrind content, and pigment addition can shift the measured values. Because the grade sits at a density of 0.934 g/cm³, its crystalline fraction is higher than that of a 0.918 g/cm³ generic LLDPE; differential scanning calorimetry of polyethylene of this density class generally shows a melting endotherm between 122°C and 128°C, although the exact peak depends on comonomer distribution and thermal history. The higher crystallinity contributes to the increased modulus and lower gas permeability relative to low-density grades, but it also reduces the free volume available for impact energy dissipation.

What Distinguishes the 3560 BUE 5114 Grade from Standard C4 LLDPE and C6/C8 Copolymers?

The most significant difference derives from the butene comonomer structure. In a butene LLDPE, the short-chain branches introduced by the comonomer are shorter and are incorporated into the crystal lamellae less efficiently than the hexene or octene branches of higher-alpha-olefin copolymers. At the same density and melt flow rate, a butene copolymer generally exhibits higher flexural modulus and yield stress but lower notched impact strength and lower environmental stress crack resistance. This is a consequence of lower tie-molecule concentration in the amorphous regions between lamellae, which is the primary load-transfer mechanism during slow crack growth. A C8-LLDPE of the same 0.934 g/cm³ density and 35 g/10 min melt flow rate would therefore be expected to show greater impact and ESCR, although published comparative data for this exact Icorene formulation are limited. The specific BUE package also differentiates the grade from unstabilized commodity LLDPE; it is intended to provide processing stability and some UV resistance, but outdoor weatherability must still be assessed against ISO 4892-2 for the final article thickness and exposure period.

Compared with high-pressure low density polyethylene (LDPE) of similar melt flow rate, the linear architecture of this grade provides higher tensile strength, higher elongation at break, and better puncture resistance, but lower melt strength and less shear thinning. The lower melt strength means that it will not perform well in air-cooled film processes; for a blown-film line with blow-up ratio above 2:1, bubble instability is likely. Compared with other Icorene grades, the 35 g/10 min melt flow rate and 0.934 g/cm³ density make the material faster-filling and stiffer than lower-flow offerings, but the reduction in molecular weight also reduces the allowable continuous stress in load-bearing parts.

The linear low density classification is not solely a density statement; it reflects the substantially linear backbone and the absence of the long-chain branching that dominates high-pressure LDPE. At injection moulding shear rates in the range of 500–1,000 s⁻¹, a high-flow LLDPE typically remains lower in viscosity than an LDPE of equivalent melt flow rate. This reduces shear heating in sprue and runner channels, but it also reduces the strong shear-thinning behavior that helps LDPE fill thick sections. Consequently, parts with thick bosses or abrupt wall transitions require deliberate gate positioning and cooling management to avoid internal voids and sink marks. Published capillary rheometry data for this exact 5114 formulation are not available in the general product page; therefore, flow simulation inputs should be obtained from the supplier rather than from generic LLDPE mastercurves.

Injection Moulding Window and Barrel Temperature Profiling for Thin-Wall Tooling

On a reciprocating-screw injection moulding machine with a general-purpose screw of 20:1–24:1 length-to-diameter ratio and compression ratio between 2.5:1 and 3.0:1, a barrel profile from feed to nozzle of 40–60°C, 180–200°C, 200–230°C, and 210–230°C is appropriate as a starting condition. The nozzle melt temperature should be maintained between 220°C and 240°C. Mould surface temperatures of 20–40°C provide cycle-time economy and acceptable surface replication for thin-wall lids. Back pressure between 5 bar and 10 bar is sufficient for melt homogenization. In thin-wall tools with wall thickness below 1 mm, injection velocity should be set high enough to prevent short shots; typical starting ram speeds are 80–120 mm/s on a 160-tonne machine, but gate geometry and runner balancing determine the final setting. The high melt flow rate of this grade reduces peak cavity pressure relative to a 20 g/10 min LLDPE, which can lower clamp force requirements in multi-cavity tools; however, it also shortens the holding-pressure window. If hold pressure is applied too long at high pressure, gates may string or freeze-off may occur too late, causing sink marks. If hold pressure is insufficient, the moulded parts may show excessive shrinkage and dimensional variability.

Residence time is the primary thermal constraint. At melt temperatures above 250°C, oxidative chain scission can reduce viscosity, shift the melt flow rate upward, and generate discoloration and volatile-related surface defects. The total barrel residence time should remain below 5 min when the melt temperature is above 240°C. In hot-runner systems, the manifold and nozzle tips should be held below 230°C to minimize drooling and stringing caused by low melt elasticity. If the material must be purged, a lower-MFR polyethylene purge grade is recommended because this grade’s high flow can leave deposits in dead spots and check rings. Moisture pickup in sealed packaging is negligible; if condensation occurs after storage in cold conditions, the pellets should be dried at 70°C for 2 h in a desiccant dryer with a dew point below -30°C before processing.

Shrinkage behaviour should be characterized according to ISO 294-4 on a 60 mm × 60 mm × 2 mm plaque at the intended mould temperature. Published shrinkage values for this exact grade are limited, but LLDPE of this density and melt flow rate generally exhibits mould shrinkage between 1.5% and 2.5% in the flow direction and between 1.0% and 2.0% transverse. Differential shrinkage in lids and flat parts can cause out-of-round or warp; post-mould cooling fixtures and careful gate position are more effective than increasing packing pressure alone. Shot-to-shot consistency on production equipment is improved when the non-return valve maintains at least 95% closing efficiency; a worn check ring in a high-flow grade can cause melt backflow and fluctuating shot masses. Coloured or compounded versions fall outside the base-resin data sheet because pigment dispersion quality and stabilizer consumption during colour masterbatch dilution can alter melt flow and long-term heat aging. Masterbatch selection should be based on a polyethylene carrier with a melt flow rate close to 35 g/10 min; a high-viscosity carrier can create unmelted pigment streaks in thin-wall sections.

Regulatory assessment of the base polyolefin is separate from the assessment of the final compounded or coloured article. For European food-contact use, the base resin is assessed under Regulation (EU) No 10/2011; overall migration testing is carried out with food simulants according to EN 1186-1 and EN 1186-14, and specific migration of additives follows the EN 13130 series where applicable. In the United States, olefin polymers may be used in contact with food if they meet the extractable fraction limits described in FDA 21 CFR 177.1520(c). For electrical and electronic equipment, applicable RoHS documentation should confirm that the grade meets the maximum concentration values of Directive 2011/65/EU Annex II, typically through screening by IEC 62321-5. Under REACH, the polymer itself is generally exempt from registration as a polymer under Article 2(9) of Regulation (EC) No 1907/2006; the monomers and any added substances have separate registration obligations. Users should request the supplier’s regulatory information letter for the exact 5114 recipe before completing food-contact or toy compliance documentation.

When the Melt Flow Rate of the Grade Becomes a Design Constraint in Closure Systems

High melt flow rate is beneficial for thin-wall filling but becomes a design constraint when the moulded part must resist sustained mechanical load or chemical contact. The 35 g/10 min melt flow rate indicates a lower average molecular weight than lower-flow grades, and molecular weight is inversely related to environmental stress crack resistance in polyethylene. In a screw-cap or snap-fit closure subjected to constant hoop stress, slow crack growth may initiate earlier than in an equivalent part made from an 8 g/10 min LLDPE. The actual stress threshold must be evaluated on the moulded article because processing orientation, gate location, and moulded-in residual stress change the apparent ESCR. Testing according to ISO 22088-3 or ASTM D1693 should be conducted on plaques or parts representative of production. Published data for this specific grade under these standards is limited; the reduced ESCR expectation follows from the high melt flow rate and butene comonomer structure. For applications requiring notched Charpy impact above 10 kJ/m² at −20°C according to ISO 179-1/1eA, an octene-copolymer LLDPE with lower MFR or a polyethylene blend may be necessary. The grade is therefore better matched to short-cycle thin-wall packaging, overcaps, and semi-structural inserts where the dominant failure modes are injection-pressure short shots, warp, and dimensional inconsistency rather than long-term chemical exposure or sub-ambient impact.

In a typical thin-wall container lid production line using a 160-tonne hydraulic injection moulding machine with a 32-cavity hot-runner mould, the high melt flow rate of Icorene 3560 BUE 5114 permits fill lengths that lower-MFR grades achieve only with elevated melt temperatures or increased injection pressure. The observed processing bottleneck is often gate blush at tunnel gates when injection velocity is set too low; raising the nozzle melt temperature to 235°C and the metering-zone temperature to 225°C reduces gate blush but narrows the thermal residence window. Dimensional stability is influenced by differential shrinkage between the flow direction and transverse direction; annealing or post-mould cooling fixtures may be required for roundness tolerances below 0.5 mm. The introduction of regrind above 20 wt% may be possible with this grade, but the melt flow rate can drift upward because of repeated chain scission, and the blend should be re-qualified under ISO 1133-1:2022 before production release. Batch-to-batch melt flow rate variation in continuous LLDPE production is typically controlled within ±2 g/10 min at a nominal 35 g/10 min; incoming quality control should verify melt flow rate and density before switching or blending lots.