Agricultural mulch films, silage covers and industrial shrouds produced from LLDPE-rich blown film lines commonly incorporate LyondellBasell POLYBATCH™ Tan LL60139/2 to control transmitted radiation and provide batch-to-batch colour consistency in film sold to construction and agricultural distributors. The masterbatch is pre-blended with virgin LLDPE and LDPE via low-shear paddle mixers or gravimetric batch blenders; gravimetric side-feeding on high-output lines with barrel diameters above 55 mm avoids screw slippage caused by pellet-pellet lubrication differences. Industry compliance for food-contact films is assessed under EU Regulation 10/2011, FDA 21 CFR 177.1520 for olefin polymers, and FDA 21 CFR 178.3297 for the colourant component; the finished film, not the masterbatch, carries the migration responsibility; for soil-contact agricultural films, REACH Annex XVII restrictions and local biodegradable/oxo-degradable rules must be checked. A starting addition ratio of 3 wt% is used for films in the 25–50 µm gauge range, while thicker silage covers at 100–150 µm may require 4–5 wt% to maintain the same transmitted colour depth because pigment concentration per unit area, not per unit mass, determines spectral absorbance. Downstream production commonly runs on a three-layer coextrusion die with a blow-up ratio of 2.0:1 to 2.5:1, frost-line height between 600 mm and 900 mm, and melt temperature set at 200–220 °C; the pigment package may raise the crystallization onset, causing a higher frost line if no adjustment is made, and increasing die lip plate-out on long runs. Optical performance is verified by ASTM D1003 haze and ASTM D2457 gloss, mechanical integrity by ASTM D882 tensile and ASTM D1709 dart drop; pigment dispersion quality is commonly assessed by ISO 18553 or film surface defect count per square metre. Terminal products include monolayer and coextruded agricultural mulch, silage covers, grain storage covers, industrial shrouds, and coloured overwrap for construction films; the concentrate is not suited to high-clarity food packaging where haze below 10% is required, because the pigment addition inherently raises wide-angle scattering.

Does a 4 wt% Let-Down Shift Part Surface Scatter and Impact Resistance in Thin-Wall Injection Moulding?

Before a tan-coloured thin-wall part is approved for freezer-rated logistics use, injection moulders dose colour masterbatch directly at the machine throat using a volumetric or gravimetric feeder synchronized to screw recovery. The sector's compliance framework includes REACH Annex XVII for restricted substances, ISO 294-1 for specimen preparation, and ASTM D638-14 tensile and ASTM D256 Izod impact for incoming lot validation; parts for food transport are evaluated under EU Regulation 10/2011 with an overall migration limit of 10 mg/dm², while non-food articles may only require a signed REACH SVHC declaration. A let-down ratio of 2–4 wt% is typical for wall thicknesses from 1.5 mm to 4.0 mm; below 1.2 mm wall, the same ratio can produce visible colour non-uniformity around gates and weld lines because high shear rates align pigment agglomerates differently than the surrounding matrix. Processing is carried out on a reciprocating-screw injection moulding machine with a 22:1 to 25:1 L/D barrier screw, back pressure set to 0.5–2.0 MPa, melt temperature held at 200–230 °C, and mould temperature maintained at 20–45 °C; injection speed is profiled so that the flow front velocity does not exceed 200 mm/s through thin ribs, minimizing jetting and non-uniform pigment orientation. Although the LLDPE carrier is not hygroscopic, surface condensation on cold pellets should be avoided when relative humidity exceeds 60%; a 60 °C hopper dryer for 2 h eliminates splay in humid plant conditions. Terminal finished products include tan-coloured industrial crates, agricultural harvest bins, freezer-rated tote boxes, bottle crates, and logistics trays where colour is used for line-of-sight sorting or brand differentiation. Published data for this specific concentrate in thin-wall injection moulding is limited; converters should run a plaque trial per ASTM D3641 to establish the relationship between let-down ratio and weld-line colour difference before full-scale release.

Rotational moulding lines running pulverized LLDPE at oven temperatures of 260–320 °C confront a specific segregation failure when pelletized masterbatch is charged without particle size reduction: the denser pigment particles separate from lighter polymer powder during mould rotation, producing swirl marks, colour streaks, and non-uniform opacity at parting lines. For tan-coloured tanks and outdoor furniture, the LLDPE-based concentrate is cryogenically ground to a particle size distribution between 300 µm and 500 µm, then dry-blended with 35-mesh pulverized LLDPE to prevent density-driven demixing. Compliance for water-contact rotomoulded articles is assessed under NSF/ANSI 61 and, in some jurisdictions, AS/NZS 4020; the masterbatch constituents must be included in a migration risk assessment, and the final tank must satisfy ASTM D1998 for polyethylene upright storage tanks where applicable. Addition ratios in rotomoulding are higher than in film because oven dwell and long thermal exposure partially degrade the carrier and reduce pigment dispersion; a starting ratio of 3–5 wt% is typical for wall sections between 3 mm and 10 mm, with the higher value reserved for thin-wall parts requiring a low L* value. Downstream production uses a biaxial rotational machine with a 4:1 primary-to-secondary rotation ratio, oven dwell of 20–35 min, and internal air temperature measured by a Rotolog or equivalent; the peak internal air temperature is held between 190 °C and 205 °C for LLDPE, and the pigmented layer must pass a cold impact test because colourant agglomerates can reduce low-temperature ductility. Terminal products include tan-coloured agricultural water storage tanks, outdoor furniture such as benches and planters, industrial totes, and corrosion-resistant storage containers; any use in potable water plumbing requires the moulder to submit the exact formulation to the certification body, as the masterbatch alone carries no potable-water listing. Incompatibilities include peroxide-initiated PE crosslinking systems: if the tan pigment contains transition-metal oxides, the peroxide decomposition path may shift, reducing gel fraction and compressive creep resistance in crosslinked rotomoulded parts; a small-scale gel content test per ASTM D2765 is required before replacing natural carrier resin with pigmented masterbatch in a crosslinked product.

Pinch-Off Weld Structural Integrity and Colourant Plate-Out in Continuous Extrusion Blow Moulding

At the pinch-off weld of continuous extrusion blow moulded containers, LyondellBasell POLYBATCH™ Tan LL60139/2 sits at the interface between the parison and the weld zone, where local pigment concentration can influence weld strength and environmental stress crack resistance. Compliance for industrial containers typically involves ASTM D638-14 for welded tensile strength, ASTM D1693 for ESCR under stress-cracking media, ASTM D256 for notched impact, and, for dangerous goods packaging, the UN 3H1 or UN 31H1 certification tests; food-grade bottles are evaluated under EU Regulation 10/2011 and FDA 21 CFR 177.1520, with the understanding that the masterbatch is not the final migration barrier. A let-down ratio of 2–3 wt% is common for side walls of 1.5–3.0 mm thickness, while a ratio above 4 wt% can reduce pinch-off ductility because inorganic pigment agglomerates create stress concentration points at the weld line; this effect is quantified by comparing welded tensile strength with an uncoloured control using ISO 527-2. The downstream process on a shuttle or rotary wheel blow moulding machine runs a melt temperature of 190–210 °C, die gap of 0.8–1.5 mm, blow air pressure of 0.55–0.70 MPa, and mould temperature of 10–30 °C; the parison length is adjusted for swell because the LLDPE carrier has higher shear thinning than a HDPE base resin, shifting diameter swell by 5–15% relative to uncoloured HDPE. Pigment plate-out on the die lip and pinch-off insert is managed by reducing melt temperature at the die by 5–10 °C and specifying chromium-coated or nitride-treated flow surfaces. Terminal products include tan-coloured 20 L industrial jerrycans, automotive washer-fluid reservoirs, agri-chemical containers with UN certification, and large-volume monolayer containers where a uniform tan colour masks post-consumer recyclate colour variation; for food or pharmaceutical contact, the finished article must pass the sector-specific migration protocol, and the concentrate carries no certification by itself.

When Thermoformed Sheet Gauges Fall Below 1.5 mm, Pigment Agglomeration and Vacuum Holes Become Interdependent

Across plug-assisted vacuum forming lines, thermoformed tan-coloured sheet for agricultural propagation trays and industrial dunnage packaging is produced on a single-screw sheet line where the concentrate is metered into the main feed port; the challenge shifts when draw depth and sheet gauge interact because pigment particles act as stress risers during plug-assisted forming. The applicable compliance matrix includes ISO 1133-1:2022 for melt flow characterization, ASTM D638-14 for tensile yield, ASTM D790 for flexural modulus, and EU Regulation 10/2011 for any food-contact propagation trays; industrial dunnage may only require a REACH declaration. A starting let-down ratio of 2–4 wt% is maintained for sheet from 0.8 mm to 4.0 mm, with the lower end used for deep-draw parts where thinning at corner radii must not reveal translucent patches; ratio verification is done by ash content testing per ISO 3451-1 or by X-ray fluorescence on the sheet. The extrusion process uses a barrier screw with 30:1 L/D and a melt pump to reduce pressure surge, with melt temperature at 220–240 °C, roll stack temperature at 70–90 °C, and take-off speed adjusted to maintain sheet thickness tolerance under ±3%. Thermoforming is run on a plug-assisted vacuum former with sheet surface temperature of 130–160 °C, plug material at 90–110 °C, and forming air pressure below 0.5 MPa for thin sheet; excessive let-down above 5 wt% is known to reduce hot tear resistance and increase pinhole formation at plug contact points. Terminal products include tan-coloured dunnage trays, agricultural propagation trays, stack-nest containers, and industrial packaging trays where colour stability under UV exposure is evaluated by ASTM D4329 UVA-340 accelerated weathering; the carrier selection of LLDPE rather than LDPE provides higher low-temperature impact for refrigerated handling but can exhibit higher shrinkage after thermoforming if the sheet is not normalized before trimming.