POLYBATCH™ Brown 10305U Concentrate Based In LLDPE is a pelletised brown colour dispersion carried in linear low-density polyethylene. The concentrate is intended for letdown in polyolefin conversion processes where a dark brown shade, opacity build, or earth-tone colouration is required without pre-drying the carrier under normal ambient conditions. All addition ratios stated in this application section are expressed as percent by weight of the total compound unless otherwise specified. Because the carrier melt mass-flow rate is batch-specific, the exact flow behaviour must be checked against the certificate of analysis using ISO 1133-1:2022 at 190 °C with 2.16 kg load. Converters should establish final colour coordinates on a 2.5 mm compression-moulded plaque or production-specification film using ISO 11664-4/CIE 1976 L*a*b* measurement before full-scale release. Published spectral reflectance data for this specific commercial grade is limited; therefore colour acceptance must be tied to physical plaques retained from the first production lot.

Does Brown 10305U Depress Tear Resistance in 50 µm Agricultural Silage Film?

In blown film extrusion of 40–60 µm silage covering films, Brown 10305U is introduced at 3.0–6.0 wt% into an LLDPE or LLDPE/LDPE blend with a melt temperature of 195–215 °C. The carrier pre-dispersion permits feeding through a gravimetric side-feed station directly into the main hopper throat, provided the screw has an L/D ratio of 24:1–30:1 and a compression zone suitable for LLDPE rheology. A die gap of 1.8–2.2 mm with a blow-up ratio of 2.0:1–3.0:1 is typical for maintaining bubble stability while incorporating a dark brown pigment package. Screen packs of 60/100 mesh are installed upstream of the breaker plate to capture agglomerates; pressure variation in excess of ±10 bar during a 30 min stabilisation window generally indicates screen blockage or insufficient filter surface area. The frost line is controlled at 6–8 die diameters above the die to prevent excessive draw resonance in thin-gauge brown film. Terminal products produced under these conditions include silage clamp covers, round bale stack covers, and temporary dark agricultural fumigation sheeting. Compliance for this application is assessed against EN 13207:2018 for thermoplastic silage films, with tensile properties verified according to ASTM D882 and tear propagation measured by ASTM D1922. The pigment system is not an ultraviolet stabiliser; if outdoor exposure beyond one harvest cycle is specified, a separate hindered amine light stabiliser package must be added and validated under ISO 4892-2. For food-contact agricultural uses, the finished film must satisfy EU Regulation 10/2011/EC migration limits and the pigment-specific clearance under FDA 21 CFR 178.3290 if the structure is placed in direct food contact.

Medium-duty logistics crates moulded from high-density polyethylene containing 2.0–4.0 wt% Brown 10305U are processed on multipurpose injection moulding machines with clamp force between 350 t and 800 t. The screw diameter is selected to maintain shot volume between 30 % and 70 % of barrel capacity, with an L/D of 20:1–24:1 and a general-purpose polyethylene metering profile. Melt temperature at the nozzle is held at 220–250 °C, while the injection pressure during cavity filling is typically 800–1100 bar and holding pressure is reduced to 400–600 bar to limit gate blush. Back pressure is maintained at 4–8 bar hydraulic to avoid screw slippage without generating excessive shear heat. For multicavity tools, a hot runner manifold set to 230–250 °C reduces stagnation of the LLDPE carrier in the melt path. Dosing accuracy must be controlled to ±0.05 wt% because colour variation in brown crates becomes visually detectable when the addition ratio drifts by more than 0.3 wt% between batches. Terminal produced parts include folding crates, vented agricultural trays, logistics pallet feet, and cold-chain distribution totes. Relevant compliance requirements include REACH Regulation (EC) No 1907/2006 as amended and material identification according to ISO 11469:2016. Impact resistance is verified by Charpy or Izod testing using ISO 179-1/1eA or ASTM D256, while load-bearing performance is assessed against the purchaser’s stacking and drop test specification. If the crates enter food handling, the converter must separately validate the finished moulding under FDA 21 CFR 177.1520 for the base polyethylene and confirm pigment-specific colourant clearance because the concentrate does not automatically confer food-contact status.

When Wood-Flour Polyethylene Decking Is Extruded Below 200 °C

Profile extrusion of PE-based wood-plastic composite decking requires Brown 10305U to be metered at 3.0–5.0 wt% relative to the polyethylene matrix before the wood flour is introduced, because late addition into a high-solids WPC melt reduces pigment distribution uniformity. Typical formulations contain 50–60 wt% wood flour, 30–35 wt% HDPE or LLDPE, and the balance composed of coupling agents, lubricants, and processing aids. The extrusion line uses a counter-rotating twin-screw extruder with L/D 28:1 and segmented screws, with barrel temperatures from 160–190 °C and die temperatures limited to 185–200 °C. The upper temperature boundary is critical because the brown pigment may shift hue if the compound residence time exceeds 90 s above 190 °C, and wood extractives can generate surface discolouration that interferes with final board inspection. Venting is operated at atmospheric pressure to remove moisture without splaying the extrudate; wood flour moisture must be controlled below 0.5 wt% before feeding. Calibration of hollow decking profiles uses dry vacuum sizing with water temperature below 25 °C to prevent rapid heat build-up in the dark brown surface layer. Terminal products include hollow decking planks, fascia boards, railing rails, and extruded fencing profiles. Compliance for load-bearing decking is evaluated under EN 15534-1:2014+A1:2017 or ASTM D7032-17, while weatherability is assessed with ISO 4892-2 and colour change measured by ISO 11664-4. Published data for the exact WPC colour shift of this concentrate is limited; therefore an in-line colourimeter or periodic plaque retention is required to establish process-specific acceptance limits.

Within extrusion blow moulding of 5 L jerricans for light-sensitive crop protection adjuvants, Brown 10305U is added at 3.0–5.0 wt% into high-density polyethylene selected for a high-molecular-weight tail that preserves parison melt strength. The extruder is a single-screw machine with a diameter of 90 mm and L/D 24:1, operating at a melt temperature of 190–215 °C and a head temperature of 200–210 °C. Parison programming requires 10–20 points to control wall thickness in the shoulder and pinch-off zones, because the brown concentrate increases opacity and can mask thin spots during visual inspection. Mould temperature is held at 10–15 °C to shorten cooling time and reduce post-mould shrinkage, while the blow pressure is set between 6 bar and 8 bar. Cycle times for 5 L containers typically fall in the range of 45–60 s, depending on wall thickness and cooling water temperature. Terminal products include 1–20 L jerricans, narrow-mouth chemical bottles, and closed-loop dispensing containers for light-sensitive agricultural formulations. The packaging must comply with UN 3H1/Y certification under the UN Model Regulations and applicable ADR/RID/IMDG provisions when used for regulated liquids. If the containers are intended for food contact, compliance with EU Regulation 10/2011/EC and FDA 21 CFR 177.1520 must be verified on the finished article. Brown 10305U should not be assumed to provide dangerous goods ultraviolet screening; if UV-sensitive contents require validated light transmission limits, the container must be tested at the finished wall thickness because pigment loading alone does not define transmission.

What Limits Pinhole Formation at 3.0 wt% Loading in Rotational Moulded Tanks?

For rotational moulding of linear low-density polyethylene agricultural sprayer tanks, Brown 10305U is dry-blended with 35 mesh pulverised LLDPE powder at 2.0–4.0 wt% using a high-intensity mixer for 60–90 s. The dry blend is then charged into a cast aluminium or fabricated steel mould heated in a forced-air oven at 280–300 °C. Peak internal air temperature is the more useful control variable and is held between 190 °C and 210 °C to densify the wall without thermal degradation of the LLDPE carrier. The biaxial rotation ratio is set near 4:1 primary-to-secondary axis, with secondary rotation adjusted to reduce wall-thickness variation in the lower corners and baffle areas. Cooling is staged with forced air followed by water mist; rapid quenching of dark brown parts can induce surface microcracking if the mould is opened below 60 °C. Pinholes in the outer wall are a known failure mode when pigment dispersion is incomplete or when oven residence time is extended more than 15 min beyond the optimum peak internal air temperature. If bubbles or surface porosity appear, the peak internal air temperature should be reduced by 5 °C increments rather than increasing pigment loading. Terminal products include 200–1500 L horizontal sprayer tanks, water storage cisterns, and chemical dosing tanks. Compliance is assessed under ASTM D1998-15 for polyethylene upright storage tanks, with wall-thickness verification by ultrasonic measurement and hydrostatic testing according to the purchaser’s pressure class. Published data for pinhole threshold limits specific to Brown 10305U in rotomoulded LLDPE is limited; confirm production window on the actual mould geometry before serial manufacture.

Caps and Closures: Gate-Freeze Control with 2.5 wt% Brown Concentrate in High-Flow LLDPE

At the 96-cavity cap injection moulding stage, Brown 10305U is let down at 2.0–4.0 wt% into a high-flow LLDPE/LDPE blend with a melt mass-flow rate of 20–40 g/10 min at 190 °C/2.16 kg according to ISO 1133-1:2022. The melt temperature is held at 220–240 °C, while the hot runner system is set to 230–250 °C to avoid premature freeze-off in narrow gate drops. Injection speed is controlled at 120–180 mm/s, with holding pressure between 700 bar and 1000 bar to pack the bridge and thread detail without excessive clamp tonnage. Cooling time is limited to 5–8 s for thin-wall closures, and mould temperature is maintained at 10–20 °C to stabilise part release. The concentrate is fed by a side-mounted gravimetric dosing unit calibrated to ±0.05 wt%; short-shot or colour-bleed conditions can indicate inconsistent dosing rather than a moulding defect. Terminal products include tamper-evident closures for agrochemical and household chemical containers, dispensing plugs, and push-pull caps. Compliance for olefin closures in food contact requires verification of the base polymer under FDA 21 CFR 177.1520 and, where applicable, the colourant clearance under FDA 21 CFR 178.3290 or EU Regulation 10/2011/EC. Closure torque retention is commonly evaluated according to ASTM D2063, while child-resistant certification follows ISO 8317 only when specified. Brown 10305U does not function as a barrier additive; if oxygen or moisture transmission limits are required, the cap design must include a separate barrier liner or coating.