In blown film extrusion of monolayer polyethylene packaging, LyondellBasell POLYBATCH™ Blue LL40445/2 Concentrate Based In LLDPE is metered into the extruder throat through a low-rate gravimetric feeder at 2.0 wt% to 4.0 wt% of the total compound for films between 40 μm and 80 μm. The LLDPE carrier is melt-compatible with LLDPE and LDPE film grades, and no pre-drying is required when bags are stored below 60% RH; if condensation is observed on pellets, a hopper dryer at 60 °C for 2 h is recommended before the material enters the feed section. On a standard 45 mm single-screw blown film extruder with an L/D ratio of 30:1 and a barrier screw, the melt temperature is maintained between 190 °C and 220 °C, the die gap is set at 1.8 mm to 2.4 mm, and the blow-up ratio is held between 2.0:1 and 2.8:1. Frost line height is adjusted from 300 mm to 600 mm to stabilise bubble geometry because the LLDPE carrier lowers melt tension relative to pure HDPE but remains shear-thinning at typical film extrusion shear rates. For food-contact packaging, the finished film must meet the overall migration limit of 10 mg/dm² under Regulation (EU) No 10/2011 and the olefin polymer requirements of FDA 21 CFR §177.1520; for packaging waste heavy metal limits, the sum of lead, cadmium, mercury and hexavalent chromium must not exceed 100 mg/kg under EU Directive 94/62/EC Annex II. Finished article types produced from this formulation include frozen food bags, agricultural silage covers, retail carrier bags and industrial liners.

What Limits Colourant Dispersal at High Throughput in Cast Film Lines?

High-speed cast film lines operating above 300 m/min introduce a dispersion constraint that is absent from lower-throughput film blowing. The concentrate is melt-diluted at 3.0 wt% to 5.0 wt% in LLDPE/LDPE cast film grades of 20 μm to 35 μm thickness; below 3.0 wt% the blue tint becomes visually weak under the high longitudinal draw ratio, and above 5.0 wt% undispersed pigment agglomerates extracted at the screen pack increase die lip build-up frequency. A cast film line configured with a 75 mm barrier screw, L/D ratio of 30:1, barrel temperatures from 200 °C to 240 °C and a screen pack progression of 40/60/100 mesh is typical. The melt passes through a flat die with a die gap of 0.5 mm to 0.8 mm and is deposited onto a chill roll held at 18 °C to 25 °C; the air gap between die lip and chill roll is kept below 25 mm to control neck-in and edge bead stability. Production failure modes observed on cast lines include streaking traceable to pigment agglomerates in the primary filter, edge tear caused by pigment-related gel particles, and colour variance when screw speed is changed without resetting the feeder calibration. Colourimetric evaluation after stabilisation should follow ASTM D2244-21. Regulatory compliance for food contact cast film relies on Regulation (EU) No 10/2011 and FDA 21 CFR §177.1520; heavy metal limits follow EU Directive 94/62/EC Annex II at 100 mg/kg sum. Finished articles include blue-tinted identification pallet wrap, garment packaging film and lamination substrates for printed flexible packaging.

When thin-wall polyethylene containers are coloured with the LLDPE-based blue masterbatch at a letdown ratio of 1:50 to 1:100, the gate region displays the most sensitive colour-defect behaviour. Addition levels of 1.0 wt% to 2.0 wt% are used for wall sections between 0.8 mm and 1.8 mm; the lower range is reserved for translucent housewares, while the upper range is needed for opaque caps and closures. An injection moulding machine with a 25 mm to 35 mm screw diameter, L/D ratio of 20:1 and a shut-off nozzle is set to a melt temperature of 200 °C to 230 °C, hydraulic back pressure of 6 bar to 12 bar, and injection velocity of 80 mm/s to 160 mm/s; screw recovery is held between 60 rpm and 120 rpm. In PE-based articles, the LLDPE carrier delays gate freeze, and cooling time may require an additional 0.5 s to 1.5 s to prevent gate strings and part deformation during ejection. If the concentrate is used in polypropylene at levels above 1.5 wt%, the LLDPE carrier forms a dispersed minor phase that can reduce weld-line tensile strength and flexural modulus; weld-line tensile properties should be checked using ASTM D638-14 before approving polypropylene thin-wall production. Compliance under the Toy Safety Directive 2009/48/EC requires migration testing according to EN 71-3:2019+A1:2021 for articles that may be placed in the mouth or used by children under 36 months; food-contact containers are verified under Regulation (EU) No 10/2011 and FDA 21 CFR §177.1520. Finished part types include thin-wall PE food storage containers, industrial crates, caps and closures for HDPE bottles and rigid housewares.

When Blue LLDPE Concentrate Enters HDPE Extrusion Blow Moulding

Parison formation in HDPE extrusion blow moulding is governed by elongational viscosity and sag resistance, and the lower-viscosity LLDPE carrier modifies this balance when added at 2.0 wt% to 3.5 wt%. In a shuttle or accumulator-head machine running a 70 mm extruder with an L/D ratio of 24:1, the parison die gap is set between 0.8 mm and 1.6 mm for containers with 0.6 mm to 1.2 mm wall thickness, and the melt temperature is maintained between 190 °C and 220 °C. The LLDPE carrier lowers melt strength above 215 °C; when accumulator head tooling runs beyond this point, top-to-bottom wall distribution shifts unless accumulator shot speed is retarded by 5% to 10%. Blow air pressure is set at 6 bar to 8 bar, and mould temperature is held at 10 °C to 20 °C for surface gloss and label adhesion. Addition ratios below 2.0 wt% cause poor colour saturation in neck pinch-off zones, while ratios above 3.5 wt% increase the risk of pigment accumulation at the parison core and create visible flow lines around the handle pinch-off. Regulatory evaluation for non-food household chemical containers falls under REACH and EU Directive 94/62/EC Annex II with a heavy metal sum limit of 100 mg/kg; if the container is intended for food contact, the finished blow-moulded part must meet Regulation (EU) No 10/2011 overall migration of 10 mg/dm² and FDA 21 CFR §177.1520. Finished article types include detergent bottles, hand soap bottles, automotive lubricant containers and industrial auxiliary chemical containers.

Pipe Extrusion Colouristic Stability Under Prolonged Screw Residence

Extended residence time of blue pigment dispersed in LLDPE carrier within a pipe extruder barrel creates a specific failure mode: speck formation from degraded pigment agglomerates at the inside wall of the screen pack and at the breaker plate. The masterbatch is added at 4.0 wt% to 6.0 wt% to natural HDPE or MDPE pipe compound in single-screw extruders with a grooved feed section and an L/D ratio of 30:1. Melt temperatures are controlled between 190 °C and 220 °C; barrel zones above 230 °C shift the blue shade and generate visible specks after 15 min of residence time, particularly when the extruder is idled during downstream sizing changes. Screen packs are positioned after the breaker plate with 60/100 mesh layers, and vacuum calibration sleeves are set to 0.95 bar to 0.98 bar with haul-off speed matched to extruder output. For pressure pipe grades, the coloured compound must be revalidated for long-term hydrostatic strength according to ISO 9080:2022 and the applicable pipe dimensions standard such as EN 12201-1 or ISO 4427-1; drinking water contact requires national approval such as NSF/ANSI/CAN 61. Colourimetric consistency is checked using ASTM D2244-21. Finished articles include PE80 and PE100 potable water service pipes, electrical conduit and telecommunications duct.

Dispersion in Roto-Moulded Polyethylene Depends on Grind Size and Oven Peak Internal Air Temperature

In rotational moulding, colour development is not achieved through shear but through thermal sintering and interstitial melt flow, so the masterbatch should be reduced to micropellets of 0.35 mm to 0.50 mm or cryogenically ground before dry blending with pulverized LLDPE of 35 mesh. Addition ratio is 1.0 wt% to 2.0 wt%; below 1.0 wt% produces mottled inner surfaces on large flat sidewalls, and above 2.0 wt% lowers impact strength because the concentrate carrier shifts the sintering rate of the base powder. Mould rotation ratios of 4:1 primary to secondary axis are used, and oven temperature is set at 260 °C to 320 °C while peak internal air temperature is held at 180 °C to 200 °C. Exceeding a peak internal air temperature of 210 °C promotes oxidative colour shift and pinholes near vents; operators monitor internal air temperature with a remote infrared sensor and stop oven dwell when the flattening time reaches 2 min to 4 min. Compliance for toys is evaluated under EN 71-3:2019+A1:2021 migration limits, and potable water tanks require NSF/ANSI/CAN 61 or equivalent national approval on the finished article. Published data for this exact concentrate grade in rotational moulding is limited; converter-run gel count, impact strength and colourimetry trials on production-scale tools are therefore required before full lot adoption. Finished article types include water storage tanks, agricultural hoppers, playground components, kayaks and insulated cool boxes.