Technical scope for POLYBATCH™ Weathered Wood 10418U Concentrate Based In LLDPE. The following application entries are restricted to polyolefin conversion methods where an LLDPE-based carrier is process-compatible: capstock coextrusion, rotational moulding, thin-wall injection moulding, extrusion blow moulding, calendered sheet thermoforming, and profile extrusion. The concentrate is a let-down colour/effect additive; it is not supplied as a ready-to-use compound. Where melt-flow compatibility is uncertain, the carrier and base resin should be compared under ASTM D1238-20 (190 °C, 2.16 kg) before production. Regulatory screening for EU export includes EU REACH Regulation EC No 1907/2006 candidate list obligations and RoHS Directive 2011/65/EU Annex II substance restrictions. Food-contact uses require independent migration testing against 21 CFR 177.1520 and EU Regulation No 10/2011, because masterbatch composition determines overall migration limits.

What processing window governs let-down in polyethylene capstock coextrusion?

The capstock route for wood-plastic composite decking introduces the concentrate at 3.0–5.0 wt% against the capstock compound on a 75 mm counter-rotating twin-screw extruder with 30:1 L/D. At loadings below 2.5 wt%, opacity in a 0.3–0.6 mm cap layer is frequently insufficient when measured under ASTM D2244-23e1; at addition above 5.5 wt%, melt pressure at the screen pack typically rises and surface drag lines can appear at the coextrusion die exit. The cap layer is processed over a wood-flour-filled HDPE core at 190–205 °C melt temperature. Exceeding 210 °C for cumulative residence time beyond 45 min has been associated with carrier viscosity drift and a visible shift in the weathered-wood shade, particularly in dark-brown and grey monotone systems. Published data for this specific shade under capstock coextrusion is limited; the cumulative residence figure is a class-level benchmark for LLDPE-carrier colour concentrates. Mechanical acceptance for exterior deck boards is anchored to ASTM D7032-17 for deck board performance, ASTM D790-17 for flexural modulus, and ASTM D256-23 for Izod impact. Weathering durability is assessed with ASTM D4329-13 (340 nm UVA lamps) and ISO 4892-2:2013 xenon-arc exposure; colour retention is reported in ΔE*ab using ASTM D2244-23e1. The terminal article class produced by this route is capped wood-plastic composite deck boards and railing profiles.

In rotational moulding, the concentrate is not pre-compounded but dry-blended with 35 mesh LLDPE powder at 1.5–3.0 wt% for wall sections of 3.0–6.0 mm. Dry-blend homogeneity is the dominant process variable; ribbon blender mixing below 15 min has produced streaking on the inner mould surface because the carrier pellets and ground powder develop different electrostatic charging. Production batches usually require 20–30 min of low-shear mixing before charging the mould. The oven cycle is controlled by internal air temperature rather than oven set point: peak internal air temperature should remain at 190–205 °C; at 210 °C or above, carrier degradation accelerates and the weathered-wood tone can shift yellow when measured under ASTM D2244-23e1. Bi-axial rotation ratios between 4:1 and 8:1 are typical, with forced-air cooling rates of 10–20 °C/min to limit warpage in large flat panels. Compliance for outdoor furniture and planters is anchored to ASTM D638-14 tensile elongation, ASTM D790-17 flexural properties, and weathering programmes based on ISO 4892-2:2013 and ASTM D4329-13. Terminal products are LLDPE garden furniture, outdoor planters, and decorative storage containers.

When Thin-Wall Injection Moulding Demands Low Gate-Flow Shear

Injection moulding of 1.5–3.0 mm wall outdoor planters and nursery containers uses 2.0–4.0 wt% let-down in an LLDPE or HDPE base. Gravimetric dosing stability must hold within ±0.2 wt%; batch-to-batch colour drift appears outside this window under ASTM D2244-23e1. On a 1,200 kN clamp injection moulding machine equipped with a 22–25 mm diameter reciprocating screw, the melt temperature is held at 190–215 °C. When hot runner gate diameters fall below 1.0 mm, injection velocities above 100 mm/s can generate local shear heating of 8–10 °C, which may initiate pigment decomposition and produce dark specks in moulded surfaces. Mould temperature is typically held at 15–30 °C; cooling time is adjusted on the production line when the concentrate is used at the upper loading boundary to reduce sink marks near bosses. Mechanical integrity is verified with ASTM D638-14 and ASTM D256-23; exterior durability is assessed by ISO 4892-2:2013 and ASTM D4329-13. The terminal product class comprises thin-wall injection moulded nursery pots, saucers, and stackable garden containers.

For extrusion blow moulded outdoor storage panels, the concentrate is let down at 3.0–5.0 wt% into HDPE or LLDPE-rich blends with wall thickness 2.0–4.0 mm. The extruder is typically a 60–80 mm single-screw machine with 25:1 L/D, feeding a parison die head with gap 1.0–2.5 mm. Melt temperature is set to 180–210 °C; holding the parison at 210 °C for more than 20 min at the die head has been related to melt fracture and inversion of the wood-grain surface effect. Pre-drying at 70–80 °C for 2–4 h is required when storage relative humidity exceeds 60%, because moisture in the masterbatch can generate splay and gloss variation. Blow moulding clamp force for such panels typically ranges from 500 kN to 1,500 kN, with blow pressure 0.6–0.8 MPa. Compliance for outdoor exposure includes ASTM D638-14 tensile properties, ASTM D790-17 flexural modulus, ASTM D1693-15 environmental stress-cracking resistance, and ASTM D4329-13 UV weathering. Finished articles are blow moulded deck boxes, outdoor cabinets, and shed wall panels.

Calendered Sheet for Thermoformed Interior Trim: Surface Defect Control

Calendered sheet extrusion for wood-grain polyolefin trim uses 2.0–4.0 wt% let-down in HDPE or polypropylene-compatible LLDPE blends with sheet thickness 0.8–2.0 mm. The concentrate is pre-dispersed through a 45 mm twin-screw extruder with 28:1 L/D before entering the sheet die; melt temperature is held at 190–205 °C, and calendering stack roll temperatures are set to 80–100 °C. Lower roll temperatures have produced free-surface unevenness that appears as gloss banding after thermoforming. During thermoforming, local thinning below 0.4 mm can amplify colour density variation by 1.5–2.0 ΔE*ab under ASTM D2244-23e1, especially in high-draw corners. For automotive or recreational vehicle interior trim, flammability is tested to FMVSS 302 or ISO 3795. Mechanical acceptance uses ASTM D638-14 and ASTM D790-17. Published data for this specific masterbatch in automotive interior trim is limited; therefore final-sheet validation under FMVSS 302 and OEM fogging standards must be completed before serial production. The terminal product class includes thermoformed interior trim panels and wall cladding for recreational vehicles.

Profile extrusion of landscape edging and fencing accessory profiles employs the concentrate at 3.0–5.0 wt% in HDPE/LLDPE blends with cross-sections from 1.5 mm to 6.0 mm. The line is configured with a 50 mm single-screw profile extruder with 30:1 L/D, a vacuum calibrator, and a puller/cutter station. Melt temperature is set to 185–205 °C; vacuum calibration pressure is maintained at −0.05 to −0.08 MPa to prevent surface drag marks and dimensional variation. At addition above 5.0 wt%, published data for thick-section shrinkage is limited; downstream calibration must be re-confirmed on the production line. Mechanical compliance is evaluated under ASTM D638-14 and ASTM D790-17; outdoor colour stability is assessed to ASTM D4329-13 and ISO 4892-2:2013. Terminal products are landscape edging, garden border profiles, and fencing accessory rails.