When LI931C is specified for unpainted exterior vehicle components, the material is injection-moulded in its natural or pre-coloured state, eliminating the paint line while retaining surface permanence under solar load. The compliance position is derived from ISO 527-2 tensile testing, ISO 179-1/1eU unnotched Charpy impact, ISO 180/1A notched Izod impact, and ISO 75-2 Method A heat deflection. Weathering acceptance for exterior automotive trim typically follows SAE J2527 xenon-arc exposure at 2500 kJ/m² with ISO 105-A02 grayscale rating ≥ 4 for black and dark grey surface colour. Blending is conducted at 100 parts LI931C with 2.0–3.5 wt% colour masterbatch; for black mouldings the final carbon black concentration is commonly 0.7–1.2 wt%. Regrind use is capped at 20 wt%, preconditioned to <0.05% moisture before feeding. Downstream production uses hydraulic or servo-driven injection machines in the 150–350 t clamp range, with L/D 20:1 general-purpose screws. The material is dried in a dehumidifying hopper dryer at 85°C for 3–4 h, with a dew point of −30°C, before processing. Barrel set points progress from 230°C at the throat to 250°C at the nozzle, with melt temperature held below 260°C to avoid acrylic-phase degradation. Mould temperature is maintained at 60–80°C; below 55°C, black grades exhibit observable gloss differential around the gate area. Pack pressure is set at 55–75 MPa and injection speed is adjusted to avoid splay at flow lengths above 150 mm. Finished component forms include exterior mirror housings, cowl vent grilles, A/B/C pillar covers, and rear lamp bezels.

What Limits Layer-to-Substrate Adhesion in Window Profile Coextrusion?

Regulatory acceptance for this segment is judged against EN 12608-1:2016 for PVC-U window and door profiles, ASTM D3679-22 for vinyl siding, ISO 4892-2 for xenon-arc weathering, and ISO 105-A02 for colour-change evaluation. In capstock coextrusion, the ASA layer is formulated from 100 phr LI931C with 1.0–2.0 phr acrylic processing aid, 0.3–0.6 phr external lubricant, 0.8–1.2 phr HALS/UV absorber package, and 3–5 wt% colour masterbatch depending on target L* value. The cap layer thickness is held at 0.20–0.25 mm, equivalent to 6–10% of total profile wall thickness. A typical line pairs a 35 mm skin extruder with 24:1 L/D and a main PVC extruder feeding a 400 mm coat-hanger die. The skin melt temperature is held between 215°C and 230°C; below 215°C, peel-back delamination at the ASA-PVC interface becomes statistically more frequent. Substrate surface temperature at the feedblock must remain above 175°C to prevent chill-layer formation. Vacuum calibration is controlled at 15–25°C; puller speed is set at 2–5 m/min according to internal profile geometry. Finished forms include window lineals, door panels, siding panels, fascia boards, and soffit profiles.

Outdoor Electrical Enclosure Moulding and UL 746C F1 Outdoor Suitability

The evaluation of LI931C for outdoor electrical enclosures centres on UL 746C F1 outdoor suitability, with UL 94 HB at 1.5 mm as the material flammability reference; actual certification is confirmed on the supplier yellow card. At enclosure level, sealing performance is certified to IEC 60529 IP65 or higher, and mechanical impact resistance is classified under IEC 62262 IK07/IK08. Where coloured housings are exposed to direct sunlight, ISO 4892-2 or ASTM G154 Cycle 1 is used for comparative durability screening rather than as an absolute lifetime guarantee. The moulding formulation is 100 parts LI931C with 2.0–4.0 wt% colour masterbatch; regrind is limited to 15 wt% because higher ratios lower weld-line impact retention. No external mould release should be used when post-mould sealing or adhesive gasketing is planned. Moulding of large enclosures is performed on 400–800 t clamp machines with low-compression screws of 2.0:1–2.4:1 ratio. Barrel temperatures are 230–250°C, mould temperature is 65–85°C, and drying is 85°C for 4 h to a dew point of −30°C. Sequential valve gating is used on covers with projected area above 500 cm² to displace knit lines away from corner bosses. Gate land thickness below 1.0 mm causes local shear discolouration in dark grey parts. Terminal product types include telecom cabinets, antenna radomes, meter housings, and IP-rated junction boxes.

On agricultural machinery lines, LI931C is used mainly as a weatherable skin over mineral-filled or glass-filled ABS for cut-sheet thermoformed panels. The standards matrix comprises ISO 4892-2 at 1500–2000 h, ISO 178 for flexural modulus, and ISO 179-1/1eU for Charpy impact, with REACH SVHC screening and RoHS 2011/65/EU Annex II restrictions checked only for electrical accessories. In the sheet construction, the LI931C cap layer is 0.5–1.0 mm thick over a 3–6 mm substrate, corresponding to 10–15% of total sheet thickness. Edge trim regrind at 10–15 wt% is reintroduced into the substrate extruder only, and the cap layer carries 0.8–1.5 wt% UV/HALS stabiliser and 3–5 wt% colour concentrate. Production proceeds by flat-die extrusion at 220–240°C melt temperature, calendering between rolls at 70–95°C, then cut-sheet thermoforming with double-sided quartz preheat to 150–175°C surface temperature. Aluminium forming tools are held at 70–85°C; plug assist is required when draw ratio exceeds 1:1. Terminal products include tractor roof panels, fender extensions, combine side covers, and enclosure claddings.

When Caravan and Marine Components Require Low Gloss Drift Under 3000 kJ/m² Xenon Exposure

For applications where the final article remains outdoors for ten years and paint delamination is the dominant field failure, qualification work focuses on gloss drift rather than simple ΔE. Xenon-arc exposure to ISO 4892-2 Cycle 1 at 3000 kJ/m² is specified, with ISO 105-A02 grayscale ≥ 4 on the exposed surface. ISO 9227 neutral salt spray at 480 h is added for marine instrument housings when metallic brackets are over-moulded. In coextruded sheet, the LI931C layer is 1.5–2.5 mm thick over ABS or glass-fibre-reinforced ABS, equivalent to 12–20% of total sheet thickness. The cap formulation is 100 parts LI931C with 1.0–1.5 wt% weathering masterbatch, 4–6 wt% pigment, 1.0–1.5 phr processing aid, and not more than 0.5 phr external lubricant to preserve adhesive bond strength after thermoforming. Twin-sheet or high-pressure forming is used, with surface preheat at 155–170°C, tool temperature 75–90°C, and cooling fixtures to control post-forming shrinkage. Published data for LI931C under marine salt-spray cycling is limited; customer-specific qualification should include adhesive peel and impact retention after exposure. Terminal forms include caravan exterior doors, marine instrument pods, spa shells, and pool step trim.

In outdoor furniture and garden tool housing production, the dominant processing routes are thick-wall injection moulding and hollow-profile extrusion. Material specification typically references ISO 4892-2 at 1500 h for colour retention, ISO 179-1/1eU for unnotched Charpy impact, and ISO 1133-1:2022 for incoming MVR verification. The formulation is 100 parts LI931C, with 0.6–1.0 wt% weathering masterbatch, 2–4 wt% colour concentrate, 1.0–2.5 phr processing aid, and up to 25 wt% clean regrind. In profile extrusion, a 25:1 L/D single-screw machine is run with barrel temperatures 210–230°C, die temperature 205–220°C, and vacuum calibration at 15–20°C. In injection moulding, the melt temperature is 230–245°C and the mould is held at 60–75°C; ribs should not exceed 60% of nominal wall thickness to avoid sink marks. Terminal products include garden furniture armrests, outdoor power tool housings, post caps, and balustrade components.