Within exterior mirror housing programs for light commercial vehicles, LG Chem ASA LI911 is injection molded as an integrally colored ASA compound after desiccant drying to a residual moisture target below 0.02 %. The drying system is typically set at 80 °C for 3 h to 4 h using dehumidified air with a dew point of -30 °C or lower; short hot-air hopper residence is insufficient when ambient RH exceeds 60 %. Nozzle melt temperature is held between 240 °C and 260 °C, while the mold wall temperature is controlled from 60 °C to 80 °C to retain high-gloss black surfaces above 90 GU at 60° specular gloss on polished P20 steel cavities. The screw uses a three-zone geometry with an L/D ratio of 20:1 and a compression ratio of 2.2:1, running at 60 min⁻¹ to 100 min⁻¹ with back pressure limited to 2 MPa to 4 MPa to limit shear heating. A weathering masterbatch based on high-molecular-weight hindered amine light stabilizers is introduced at 2 wt% to 3 wt%, and carbon black is adjusted to a final loading of 0.5 % for UV opacity. Post-mold shrinkage is checked after conditioning at 23 °C and 50 % RH per ISO 291, with maximum flow-direction shrinkage near 0.5 % measured to ISO 294-4. Molded housings are qualified by SAE J2527 xenon arc exposure for 1,500 kJ/m² with ΔE below 2.0; the terminal applications are mirror shells and door garnish panels on cab-style pickups and medium-duty trucks where painted ABS had failed by coating delamination within 36 months.

What Processing Window Prevents Sink Marks in Thin-Rib Outdoor Power Equipment Housings?

String trimmer and leaf blower shrouds with nominal wall sections from 2.0 mm to 2.5 mm are filled by the high melt-volume-flow character of LI911, reported near 20 cm³/10 min when tested at 220 °C under 10 kg to ISO 1133-1:2022. This fluidity permits a filling pressure reduction of 15 % to 25 % versus medium-flow ABS grades of comparable heat resistance, but it also increases sink-mark risk above bosses and ribs when packing is too short. Gate freeze is verified by holding pressure at 50 MPa to 70 MPa for 4 s to 6 s after velocity-pressure switchover at 95 % of fill volume. Mold temperature is maintained at 50 °C to 70 °C; higher settings improve knit-line strength but extend cycle time beyond 45 s. Ejection occurs when the average core surface temperature reaches 85 °C. The resin is dried at 80 °C to 90 °C for 3 h to 4 h, with residual moisture limited to 0.03 %. For field weatherability, injection molders add 2.5 wt% of gray or orange color masterbatch and 1.5 wt% of a UV absorber package; the compound retains more than 70 % of initial 60° gloss after 1,000 h xenon arc testing per ISO 4892-2 Cycle 1 with daylight filters. Terminal parts include grass trimmer motor housings, chainsaw covers, and compact pressure washer cabinets for cordless outdoor equipment.

Outdoor Telecommunication Enclosure Weathering and Fire Safety Margins

In telecom access cover and small-cell radio shroud production, LI911 is specified where color stability must exceed that of ABS and warpage must remain lower than that of polycarbonate blends. The resin is molded with a melt temperature of 245 °C to 260 °C and a mold temperature of 70 °C to 80 °C to reduce post-mold distortion in flat lid areas above 400 mm span. Shrinkage after 24 h is measured from 0.4 % to 0.6 %; fixtures accept textured surfaces with draft angles of 1.5° per side. Because the grade is unfilled, enclosure designers use creep-modulus-based deflection calculations rather than short-term tensile data. Outdoor exposure is validated by ISO 4892-2 Cycle 2 for 2,000 h; CIELAB ΔE after exposure is specified below 3.0. Unfilled LI911 is recognized for outdoor use in electrical equipment enclosures under UL 746C and carries a UL 94 HB flame classification at 3.0 mm; the HB classification is not acceptable where V-0 or 5VA ratings are required, and published evidence for LI911 with phosphorus-based flame-retardant packages is limited. Fastening bosses require brass inserts or thread-forming screws with a pilot-hole diameter equal to 70 % of the thread outside diameter to prevent low-temperature boss cracking. Terminal components are pole-mounted antenna covers, fiber distribution box doors, and EV charger housing bezels exposed to rain and UV.

Assessment	Test method or directive	LI911 condition or acceptance
Outdoor enclosure suitability	UL 746C	f1 outdoor suitability for non-structural enclosures; no cracking after UV and water cycling
Flame classification	UL 94	HB at 3.0 mm minimum thickness
Xenon arc weathering	ISO 4892-2 Cycle 2	ΔE < 3.0 after 2,000 h
Hazardous substances	RoHS 2011/65/EU Annex II	No intentional addition of restricted lead, cadmium, mercury, hexavalent chromium, PBB, PBDE, or specified phthalates
Empty enclosure impact	IEC 62208	IK08 after conditioning to -25 °C

When Unpainted ASA Replaces Painted ABS on Commercial Vehicle Cab Exteriors

Because truck cab side fairings and roof deflectors are sensitive to coating adhesion loss at sharp radii and to gloss mismatch between adjacent metal panels, the switch from painted ABS to integrally pigmented LI911 removes primer and topcoat application, cutting one bake cycle of 80 °C for 30 min and reducing volatile organic compound emissions from the paint line. The ASA compound is dried for 4 h at 85 °C and processed with a melt temperature of 250 °C and mold temperature of 70 °C on an injection machine with clamp force of 3,000 kN to 4,000 kN for parts with projected areas near 1,200 cm². Gate locations are shifted toward the part center, and cold slug wells are placed at runner ends to prevent surface streaking. Antistatic and UV packages are pre-compounded; downstream dry blending is not used because minor constituent segregation in the hopper produces visible tiger striping. Appearance is inspected under D65 lighting at 1,000 lux, with no flow lines, sink marks, or splay permitted, and color difference is measured by ISO 11664-4 with ΔE below 1.5 against an approved master. Weathering is tested per DIN EN ISO 4892-2 with 1,800 kJ/m²; the unpainted black surface retains a minimum 60° gloss of 75 GU after exposure. Continuous service temperature in the upper fairing zone is limited to 90 °C; above this threshold, thermal expansion and UV-induced oxidation accelerate surface chalking. Terminal applications include roof caps, cab side fairings, mirror arms, and wind deflector end caps on Class 5-7 trucks.Recreational vehicle window frame extrusions and roof hatch trims are produced from high-flow ASA to balance UV durability during prolonged outdoor storage and low-temperature impact during winter transit. LI911 is injection molded into frames with wall thicknesses from 1.8 mm to 3.5 mm and corner joints that are either heat-staked or ultrasonically welded. Because ASA is slightly hygroscopic, drying to 0.02 % moisture content at 80 °C for 4 h is mandatory before processing; failure to dry produces silver streaks near the gate and reduces Charpy impact strength by more than 25 % compared with optimally dried material. The mold surface is textured to VDI 3400 reference 24 to 27 to hide minor flow marks; ejection draft is 1° to 1.5° on textured surfaces. Melt temperature is 235 °C to 250 °C, and mold temperature is 60 °C to 70 °C. Impact resistance after 1,000 h of xenon arc exposure is checked by ISO 179-1/1eA at -30 °C; parts are expected to show no brittle fracture. The terminal products include vertical sliding window sash covers, roof vent bezels, and compartment door outer skins for caravans and motorhomes. For white and beige formulations, titanium dioxide is added at 3 wt% to 5 wt%; this loading raises viscosity slightly and requires a 5 °C increase in nozzle temperature to maintain the same filling pressure. No painting is required, and aftermarket replacement parts can be molded in low annual volumes without maintaining color-matched paint inventory.

Controlling Gate Blush in High-Flow ASA Spa Equipment Housings

Spa heater housings and salt-chlorine generator enclosures, both water-contact covers, are molded from LI911 with multiple edge gates or a single submarine gate to minimize visible gate blush. The high melt-flow rate, approximately 20 g/10 min under ISO 1133-1:2022 at 220 °C and 10 kg, makes gate-induced jetting more likely when the gate land length is below 1.0 mm. The molder should use a spherical or fan gate with a land length of 1.2 mm to 1.8 mm and a gate diameter not exceeding 80 % of the wall thickness. Melt temperature is set at 240 °C to 260 °C, while mold temperature is 65 °C to 75 °C; filling speed is profiled from 30 mm/s to 60 mm/s to control the flow front. The unfilled ASA grade has limited hydrolytic stability in permanent immersion above 60 °C, so the design should avoid direct contact with pressurized water lines; gasketed covers and external shrouds are acceptable. Exposure to chlorinated water at 3 mg/L free chlorine for 2,000 h at 40 °C generally produces minor surface haze but no significant tensile strength loss; however, published grade-specific long-term data for this configuration is limited. Terminal parts include spa pump lids, heat pump cabinets, pool chemical dispenser covers, and salt cell housing shells. Molded-in inserts should be brass and placed at least 1.5 times the insert diameter from the edge to prevent stress cracking.