POLYBATCH™ Yellow 20232U Concentrate Based in LLDPE — Application-Specific Processing and Compliance Profiles

At monolayer blown film thicknesses between 18 µm and 80 µm, the LLDPE carrier of POLYBATCH™ Yellow 20232U is added gravimetrically at the extruder throat rather than through a side feeder, because side feeding of a pelletised LLDPE concentrate can create feed-rate variance when the hopper loader cycles above 400 kg/h. A screw with a 25:1–30:1 L/D barrier section and a Maddock mixing element is the minimum configuration for distributive colour mixing in a single-flight film extruder. The die gap is set between 1.8 mm and 2.5 mm, the blow-up ratio is held between 2.0:1 and 3.0:1, and the frost line is maintained at 5–8 die diameters above the air ring. For a 40 µm high-opacity yellow sack film, the starting addition is 3 wt% (30 g/kg); converters drop to 2 wt% for 70–100 µm heavy-gauge industrial liners and raise to 4 wt% for 20 µm films to compensate for colour thinning after bubble orientation. Melt temperature at the die should stay between 180°C and 215°C; internal bubble cooling is preferred above 150 kg/h output to remove frictional heat and stabilise bubble geometry.Colour is not in itself a food-contact permit. When the film is intended for packaging food, the final article must satisfy Regulation (EU) No 10/2011 Annex I migration limits using test method EN 1186-1:2002 and the relevant food simulants, while the US condition of use requires FDA 21 CFR 177.1520 for the olefin film and 21 CFR 178.3297 for the colorant. For non-food industrial packaging, the heavy-metal sum in the packaging article should comply with EU 94/62/EC as amended, with lead, cadmium, mercury and hexavalent chromium below 100 mg/kg using an accredited acid-digestion/ICP-OES protocol. Terminal products include waste segregation sacks, high-visibility industrial liners, coloured collation shrink hoods and vapour barrier sheeting; these applications do not require full food-contact migration testing unless the film enters a food-packaging line.

What Gate Shear History Reveals About Colour Streaking in LLDPE-Carried Yellow Concentrates?

In multi-cavity injection moulding of polyolefin caps and closures, gate shear rates exceed 10,000 s⁻¹ at fill speeds between 150 mm/s and 400 mm/s, and poorly distributed masterbatch agglomerates are drawn into micrometre-scale streaks before the melt front reaches the cavity wall. A starting let-down of 2 wt% is used for a 26 mm HDPE beverage closure with a wall stock of 0.8 mm; thin-wall lids below 0.6 mm are raised to 3 wt% only after confirming that the hot-runner manifold holds temperature within ±3°C across all drops. The injection moulding machine should have a screw L/D of at least 20:1, back pressure of 30–80 bar, and a melt temperature of 200–230°C. Clamp force for a 48- or 96-cavity closure stack typically lies between 200 t and 400 t, and the hot runner is balanced to ±2% fill variance. Colour acceptance testing uses CIELAB ΔE*ab against a moulded standard, with the measurement geometry defined by ISO 11664-4:2008. If the closure is used in food or beverage contact, the final article is tested for migration under Regulation (EU) No 10/2011 using EN 1186-1:2002, and US conformity is assessed under FDA 21 CFR 177.1520 for the olefin polymer and 21 CFR 178.3297 for the colorant; organoleptic transfer is screened by ISO 13302:2008. Terminal products include tamper-evident caps, closures for bottled water and non-carbonated beverages, overcaps for detergent bottles, and pail lids.Sheet extrusion trials with polished chrome rolls and 400–1,200 µm sheet gauge reveal a different risk profile: pigment plate-out on the middle roll when roll temperatures are held below 70°C and roll-release agents are not used. The masterbatch is pre-blended with HDPE or LLDPE at 2–4 wt%; at 2 wt% the colour intensity is suitable for dense yellow trays, while 4 wt% is reserved for thin-gauge lids where thermoforming thins the sheet and reduces apparent colour strength. A 30:1 L/D single-screw extruder with a barrier mixing section, melt pump, and flex-lip die is used; the melt temperature is maintained at 200–230°C, and the screen pack is built as 80/100/120 mesh. The polishing stack is run with the first roll above 85°C, the middle roll at 70–85°C, and the third roll below 60°C to avoid plate-out and gloss banding. For food-contact trays, lids, or clamshells, the finished article is evaluated under Regulation (EU) No 10/2011 Annex I using EN 1186-1:2002 migration testing with simulant A, B, C or D2 as applicable; the US route uses FDA 21 CFR 177.1520 and 21 CFR 178.3297, with extraction testing conducted under the intended conditions of use. Non-food handling trays and material handling containers are typically assessed for heavy metals under EU 94/62/EC and TPCH packaging toxicity limits. Terminal products include thin-wall container lids, stackable industrial parts bins, storage-case shells, and coloured tray liners for material handling.

Die Swell, Parison Wall Uniformity, and HDPE Bottle Colour Strength at 1.5–3.0 wt% Yellow Loading

Extrusion blow moulding of HDPE bottles using an LLDPE-carried colour concentrate produces a measurable shift in die swell because the LLDPE carrier has lower zero-shear viscosity than the main HDPE bottle grade; this shift must be compensated in the die gap and parison programming, not by raising melt temperature. For a 250 mL household chemical bottle, the starting addition is 2 wt%; for thin-walled 500 mL detergent bottles the level drops to 1.5 wt%, while 20 L jerrycan shoulders and pinch-off zones may require 3 wt% to avoid pale seams along the flash line. Machine configuration includes an accumulator or continuous blow moulder with a die gap of 1.5–2.5 mm, a melt temperature of 185–205°C, and a parison drop time that is adjusted when the colour load shifts by more than 0.5 wt%. Blow pressure is maintained between 6 bar and 10 bar, and the mould chiller is held at 8–12°C to stabilise pinch-off welding. When the containers are used for aggressive fluids, the pigmented compound is tested for environmental stress crack resistance by ASTM D1693-15 on the final mixed resin, and the filled container is subjected to chemical compatibility testing per ASTM D543-21. Dangerous goods packaging for agrochemical or lubricant products may require UN certification under ADR/RID/IMDG 6.1.3, which imposes stackability, leakproofness and permeation requirements that the masterbatch alone does not certify. Terminal products include household chemical bottles, automotive lubricant containers, agrochemical jugs, and non-food cosmetic containers.

High-Backpressure Mixing Sections Reduce Colour Lensing During Pipe Od Formation

On pipe extrusion lines running 200–800 kg/h, the melt stream exiting a spiral mandrel die can develop radial colour-lensing—an alternating yellow intensity pattern at the outer diameter—when the base HDPE has an MFI below 0.5 g/10 min as measured by ISO 1133-1:2022 and the colour concentrate is added only at the main hopper. For yellow non-pressure conduit and cable ducting, the starting addition is 2 wt%; for buried gas-pipe colour coding, compounders may use 3–5 wt% only after hydrostatic testing and classification of the final pipe compound. The extruder is a single-screw design with an L/D of 30:1–36:1, grooved feed section, and a screen pack of 40/60/80 mesh. Melt temperature is held at 190–220°C, die head pressure between 200 bar and 400 bar, and the vacuum calibration tank is operated at −0.2 bar to −0.5 bar. Published data for this specific concentrate in certified gas distribution pipe is limited; pipe certification under ISO 4437-1:2020 is held by the pipe compound or pipe producer, not by the masterbatch supplier. For hydrostatic acceptance, the finished pipe is tested per ISO 1167-1:2006 and the PE material designation is assigned under ISO 12162:2009. Terminal products include yellow gas distribution pipe where a qualified compound is used, underground cable conduits, and protective sheathing for district heating lines.

When Pellet Concentrate Meets Rotational Moulding Powder, Pre-Compounding Outweighs Dry Blending

Rotational moulding uses 35-mesh PE powder with a particle-size envelope of approximately 150–500 µm; dry blending Yellow 20232U pellets with powder before charging the mould produces specking because the LLDPE carrier pellets are outside this range and do not fuse into the wall at the same rate as the powder bed. Pre-compounding into ground LLDPE at 1–2 wt% is the controlled route; if dry blending is unavoidable on low-cost safety-part lines, the addition is raised to 3 wt% to hide surface specking, but wall-colour variance increases. The machine cycle uses an oven set at 280–320°C, an internal air temperature of 180–220°C, and a biaxial rotation ratio of 4:1 to 6:1; the mould surface is maintained at 40–60°C during demoulding to prevent warpage. For toys or playground panels, the final article is tested for migration of elements under EN 71-3:2019+A1:2021, with specific migration limits applicable to the intended age group. For food-contact storage tanks, EU 10/2011 and FDA 21 CFR 177.1520/178.3297 apply. For chemical storage tanks, the pigmented powder or pre-compounded resin is subjected to chemical resistance testing per ASTM D543-21 under the intended immersion conditions. Terminal products include safety barriers, playground panels, drip trays, agricultural chemical dosing tanks, and material handling bins.