POLYBATCH™ Forest Green LL30318 concentrate based in LLDPE is a pigment-loaded polyolefin masterbatch for melt blending into polyethylene and, after documented compatibility testing, certain polyolefin copolymer systems. The LLDPE carrier phase influences melt viscosity, solid-state density, die swell, and cooling behavior in the final article. Because the exact pigment loading and thermal stability ceiling of the concentrate are not publicly disclosed in this document, all numerical processing values are industrial starting ranges rather than product-specific specifications. Before line trials, the base resin, concentrate, and diluted blend should be characterized by melt flow rate under ISO 1133-1:2022 at 190°C/2.16 kg and by density under ASTM D792-20. These tests do not predict color acceptance, but they identify viscosity mismatch and solids-conveying differences on production equipment. The final article must be tested for mechanical performance, weathering, and regulatory compliance under the standards applicable to the intended market. The concentrate is not a finished food-contact material, and its presence does not automatically confer regulatory clearance to a molded or extruded part. When pellet surface moisture exceeds 0.1 wt% after storage at relative humidity above 60% for more than 24 h, pre-drying at 70°C for 2 h is a typical boundary condition. Avoid compounding with oxidizing additive systems such as peroxide masterbatches without first verifying pigment thermal stability.

What Limits Let-Down Ratio in Blown Film Without Sacrificing Shade Depth?

Blown film conversion of LLDPE-based forest green formulations generally begins with let-down ratios between 3.0 wt% and 5.0 wt% for thickness between 25 µm and 80 µm, though the optimum for LL30318 must be confirmed by pilot runs. The gravimetric dosing system should be verified by feeding the concentrate through a loss-in-weight hopper with an expected standard deviation below 0.2% of set point. Feeder variability at low ratios can produce banding and striations in the bubble before the film reaches the collapsing frame. A single-screw extruder with 30:1 L/D, a barrier screw, and a spiral mandrel die is a representative line configuration. Barrel temperatures from 185°C to 220°C are common for LLDPE-rich blown film, with die temperature set at or slightly above the upper barrel zone. Screen packs of 150 µm to 250 µm protect the die from agglomerates without generating excessive pressure. If die-lip plate-out appears within 4 h of startup, the melt temperature should be lowered before increasing concentrate dilution. Color strength in film is thickness-dependent; gauge variation across the web translates directly into CIELAB ΔE*ab changes. A process capability study on film color should combine online thickness measurement with spectrophotometric readings using ISO 7724-1 and ISO 7724-2. When the ratio exceeds 6.0 wt%, LLDPE films may show a loss of dart impact strength measured under ASTM D1709 or ISO 7765-1 and an increase in haze measured under ASTM D1003. Weatherable greenhouse and agricultural films should be tested under ISO 4892-2; the concentrate does not substitute for hindered amine light stabilizers. Food-contact printed films require the finished multilayer structure to comply with 21 CFR 177.1520 and 21 CFR 178.3297.

Cast Film Extrusion with Chill-Roll Polishing Stacks and Dispersion Defects

Cast film lines impose rapid quenching on the LLDPE carrier, which can freeze poorly dispersed pigment particles before they have fully separated in the melt. The concentrate is added at 2.0 wt% to 4.0 wt% for monolayer cast film in the 25 µm to 70 µm range, though trial ratios should be confirmed because base resin melt index and carrier viscosity both affect dispersion. A cast film extruder typically uses a 30:1 L/D screw with a feed section optimized for LLDPE and a Maddock mixing section. Melt temperatures between 200°C and 240°C are normal for polyolefin cast lines; higher temperatures reduce melt viscosity but may degrade heat-sensitive green pigments. Chill-roll temperatures below 20°C can increase surface haze and make the green shade appear lighter; temperatures above 35°C may cause blocking and transfer of the concentrate color to the roll surface. Die gap settings from 0.4 mm to 0.8 mm allow the melt draw ratio to be adjusted without over-shearing the pigment particles. Dispersion quality should be assessed by extruding a thin film and inspecting backlit defects at 10× magnification or by using the classification approach in ISO 18553. Products include silage cover films, greenhouse overwraps, agricultural stretch films, and printed packaging laminates. For food-contact applications, final-article migration testing under EU Regulation 10/2011 and 21 CFR 177.1520 is mandatory because the concentrate is not cleared as such.

Rotational molding of forest green polyethylene parts starts with dry blending rather than melt compounding. A starting let-down range of 25:1 to 50:1 by mass is often evaluated; the optimum ratio depends on the base resin particle-size distribution and the flow characteristics of the pulverized material. The masterbatch pellets must be ground or selected to match the pulverized polyethylene powder to avoid segregation during mold charging and rotation. If particle-size mismatch exceeds 1.5:1 between carrier pellet and powder, separation can appear as streaking in thin walls and as agglomerates in corners. Oven air temperatures of 260°C to 315°C and internal air temperatures approaching 230°C are typical for LLDPE rotational molding. The long oven cycle, often 20 min to 40 min, requires the base resin and concentrate to tolerate extended heat exposure. Shade variation in the final part is also affected by wall thickness and cooling rate; thick sections may appear darker because of differences in crystallinity, not because of higher pigment concentration. Mechanical tests on rotomolded parts should follow ASTM D256 or ISO 180 for impact and ASTM D638-14 or ISO 527-2 for tensile properties. Potable water tanks and food-handling containers require specific material approval, such as NSF/ANSI 61 for drinking water system components in North America. The concentrate supplier’s generic compliance statement does not replace finished-part certification. Published product-specific data for LL30318 in rotational molding is limited; mold-side trials at multiple ratios are necessary.

If the Molding Compound Contains Post-Consumer Recyclate, the Carrier Resin Must Overcome Contamination Acid Scavenger Interactions

In injection molding of horticultural pots, crates, and caps, the concentrate is usually metered at 1.5 wt% to 3.5 wt%. The LLDPE carrier may reduce the melt temperature or melt viscosity of a high-flow LDPE or LLDPE base resin, which modifies filling pressure and gate freeze-off. If the base resin contains post-consumer recyclate, acid scavengers, residual adhesives, or zinc stearate, there is a risk of shade drift toward yellow or a loss of chroma because certain green pigments are sensitive to acidic or metal-bearing process impurities. The specific pigment package in LL30318 is not disclosed, so compatibility must be confirmed by injection molding plaques and measuring ΔE*ab per ISO 7724-1 and ISO 7724-2. A controlled screening run can use 0.5 MPa to 1.0 MPa back-pressure and screw speeds below 220 rpm on a 30:1 L/D injection screw. Nozzle melt temperature should be checked with a needle pyrometer before increasing screw RPM. Hot-runner systems with shear rates above 1,000 s⁻¹ can generate frictional heat and cause pigment degradation in runner channels. For toy applications, the final molded part must meet element migration limits in EN 71-3 or ASTM F963. Electrical or electronic components must meet RoHS 2011/65/EU, which requires full material disclosure from the supplier and testing per IEC 62321. Published product-specific mechanical data for this concentrate in recycled streams is limited.

Pipe and profile extrusion from medium-density or high-density polyethylene introduces a viscosity delta because the LLDPE carrier has lower melt viscosity than many HDPE pipe compounds. The let-down range should be limited to 2.0 wt% to 4.0 wt% until the formulation is fully validated for pressure rating and dispersion. Single-screw extruders with 25:1 to 30:1 L/D and grooved feed sections are typical for polyolefin pipe; a static mixer or dispersion section improves color uniformity. Melt temperature at the die is usually set according to the base HDPE pipe grade, between 190°C and 225°C. Screen pack pressure should remain below 25 MPa; elevated pressure from fine filtration can increase melt temperature and degrade the pigment package. Dispersion is assessed on pipe wall sections or compression-molded plaques using methods such as ISO 18553. Irrigation and drainage pipes exposed to sunlight must be evaluated under ISO 4892-2; the green concentrate does not replace UV stabilizer packages. Pressure testing follows ISO 4427 or equivalent product standards, and low-level pigment addition does not remove the need for full hydrostatic design basis qualification. Drinking water components require NSF/ANSI 61 validation on the finished pipe. End products include landscape irrigation lines, protective conduit, and green profiles for outdoor infrastructure.

Thermal stability becomes the limiting variable in sheet extrusion and thermoforming.

Sheet extrusion and thermoforming of forest green polyolefin sheet require particular attention to heat history. The concentrate may be diluted into LLDPE or LDPE sheet at 3.0 wt% to 6.0 wt%. Edge trim is frequently reprocessed into the sheet feed; if reground trim already contains pigment, the fresh concentrate addition must be reduced in proportion to the recycle ratio. A recycle stream at 30 wt% to 50 wt% of the total feed can increase the effective pigment concentration if the fresh let-down is not compensated. Sheet die temperatures between 190°C and 230°C are common for polyolefin products. Extended residence time above 10 min at elevated temperature may cause the green shade to shift; the specific thermal stability of LL30318 is not disclosed. Thermoforming draw ratios above 2:1 in corners and ribs lead to local thickness reduction and therefore visible shade variation even when pigment distribution is uniform. Formed parts should be measured with a spectrophotometer per ISO 7724-1 and ISO 7724-2 at multiple locations to quantify this effect. End products include outdoor storage containers, agricultural trays, recreational panels, and material-handling liners. Packaging applications fall under EU 94/62/EC and require verification that the finished package meets heavy metal concentration limits. For food packaging sheet, migration testing under EU Regulation 10/2011 and 21 CFR 177.1520 is required.

Extrusion blow molding of agrochemical containers and garden chemical bottles imposes specific chemical resistance demands that the color concentrate cannot satisfy alone. The LLDPE carrier may reduce melt strength in high-density polyethylene blow molding grades, so parison formation and wall thickness distribution must be checked at a starting let-down ratio of 2.0 wt% to 4.0 wt%. Die swell differences between the base resin and the concentrate can shift the parison profile; operators should record parison length, die gap, and top/bottom wall thickness after each ratio change. Melt temperature at the die should follow the base resin’s datasheet, typically between 180°C and 220°C. Pigment defects in the pinch-off region and chisel area should be inspected under 10× magnification. Stress-cracking resistance of filled bottles should be verified per ASTM D1693 because colorants and carrier resins can affect ESCR. For dangerous goods containers, UN certification testing is performed on the finished container; the masterbatch addition must be validated as part of the full packaging design. Food-contact bottles require compliance under 21 CFR 177.1520 and 21 CFR 178.3297, or EU Regulation 10/2011. The concentrate’s regulatory status in a final blow-molded article is dependent on the base resin, let-down ratio, and processing conditions.