When Nippon A&L UNIBRITE® ASA UA-1300 Replaces Chromium-Plated ABS in Automotive Mirror Housings

In exterior mirror housings, cowl grille covers and roof ditch mouldings, Nippon A&L UNIBRITE® ASA UA-1300 is specified as a 100 wt% base resin where the acrylate ester elastomer phase retains notched Charpy impact above 10 kJ/m² under ISO 179-1/1eA after 2000 h xenon arc exposure, whereas electroplated ABS and painted ABS exhibit delamination at sawcut edges and gloss loss after stone chipping. Compliance is driven by SAE J2527:2017 exterior weatherability testing, ISO 4892-2:2013 cycle 2 with a total radiant exposure of 3000 kJ/m² measured in the 300–400 nm range, ISO 527-2/1A/50 tensile modulus for boss pullout calculations, ISO 178 flexural modulus for clip tower design, and ISO 11469 marking together with ISO 1043-1 abbreviation ASA. Formulation addition ratios are 100 phr of UA-1300 pellets, 1.0–3.0 wt% exterior-grade colour masterbatch, 10–20 wt% clean post-industrial regrind recovered from sprues and runners, and no additional UV absorber unless a custom colour above 3 wt% is selected because the base polymer already carries a stabilizer package. Production is injection moulding on a reciprocating screw machine with L/D 20:1 to 25:1 and compression ratio 2.2:1 to 2.6:1; moisture after desiccant drying at 80–85 °C for 3–4 h must remain below 0.05 wt%, with dryer dew point at −30 °C or lower, because moisture contents above that threshold generate silver streaks on Class A surfaces. Melt temperature is maintained at 235–250 °C, mould temperature at 50–70 °C, cavity pressure at 35–50 MPa, and shot volume at 50–70% of barrel capacity to limit residence time and thermal history. The critical process conflict occurs at the weld line behind the mirror glass adjustment boss: at 20 wt% regrind and 60 °C mould temperature, weld-line Charpy impact is typically 80–90% of virgin values, but raising regrind above 20 wt% or lowering mould temperature below 45 °C reduces cold-impact resistance at −30 °C and causes microcracking around screw bosses after thermal cycling. Production-scale experience on 350 cm² projected-area mirror shells shows clamp force of 120–175 t is required at 35–50 MPa cavity pressure, and mould temperature variation of ±3 °C across the cavity creates batch-to-batch gloss variation on unpainted surfaces. Terminal product types include unpainted and painted exterior mirror shells, cowl top covers, windshield side trims, roof ditch mouldings, and painted rear quarter trim plates.

Coastal outdoor HVAC condenser cabinets and electrical disconnect boxes moulded from UV-stabilised UNIBRITE® ASA UA-1300 are specified for salt-spray and ultraviolet service where flame-retardant ABS is documented in polymer weatherability literature to chalk and lose impact before ASA grades reach comparable failure endpoints. The compliance framework includes UL 746C outdoor suitability and UV water-exposure conditioning, IEC 60529 IP65/IP66 enclosure ingress requirements, ISO 4892-2:2013 for colour stability, and RoHS Directive 2011/65/EU Annex II in electrical and electronic equipment end uses; grade-specific UL 746C recognition must be verified because ASA grades vary in UV stabilizer loading and UA-1300 should not be assumed to carry an f1 rating without a current UL yellow card. Formulation for these enclosures is 100 phr of UA-1300, 2–3 wt% of black or dark-grey masterbatch for opacity, and 0.5–1.0 wt% external processing lubricant only where mould friction on deep draw ribs otherwise causes haze; white and light-grey versions may require 4–6 wt% rutile TiO₂ concentrate to prevent UV breakthrough at wall stock below 2.5 mm. Downstream production is carried out on large-platen injection moulding machines with hot runner valve gates and sequential fill; melt temperature is 235–245 °C, mould temperature is 50–65 °C, injection pressure is 70–110 MPa, and holding pressure is 55–70 MPa for 5–8 s/mm of nominal wall. Deep ribs around latch bosses are prone to sink and stress whitening; field adjustments reduce pack time by 15% and use gas counterpressure or foam core where part weight exceeds 2.0 kg. Terminal product types include outdoor condensing unit top panels, louvered discharge grilles, disconnect boxes, heat pump deflectors, and sealed enclosure shells for outdoor control electronics.

What Limits Capstock Melt Temperature in ASA/PVC Coextrusion?

In coextruded window lineals and siding, UNIBRITE® ASA UA-1300 is processed as a capstock by feeding pellets to a 24:1 single-screw extruder with a barrier screw, while the PVC core is plastified on a 32:1 counter-rotating twin-screw extruder; the two melt streams combine in a feedblock at 225–235 °C and pass through a coat-hanger or profile die. The upper melt temperature is constrained by the PVC core: when the ASA stream exceeds 235 °C, conductive heat at the feedblock accelerates PVC dehydrochlorination, producing hydrochloric acid that causes brown streaks at the interface and degrades the capstock melt. The lower limit is 220 °C; below this melt elasticity and melt strength of ASA fall sufficiently to create interfacial instability, edge tear and longitudinal gauge variation in the vacuum calibration tank. The processing window is therefore approximately ±5 °C, and production-scale experience on lines with haul-off speeds of 1.2–3.5 m/min shows that melt pump pressure variation must remain below ±0.5% to avoid visible thickness bands. Formulation is 100 phr UA-1300 for the cap layer, 1.0–2.0 phr acrylic processing aid, 0.5–1.0 phr external paraffin wax, and 6–10 phr rutile TiO₂ for light-coloured surfaces or 1–2 phr carbon black for dark brown/black capstock. The cap layer is maintained at 8–12% of the total wall thickness and no less than 0.15 mm; below 0.12 mm UV shielding becomes insufficient and microcracks propagate from calibration tank impingement points after outdoor exposure. Vacuum calibration water temperature is held at 15–20 °C; lower water temperatures increase capstock skin stress and produce frosty bands after sunlight exposure, while higher water temperatures reduce cooling efficiency and cause profile bow. Compliance anchors for building products include EN 12608-1:2016 for unplasticized PVC profiles, ISO 4892-2:2013 for accelerated weathering, ASTM D3679-19 for rigid PVC siding, and EN 13501-1 reaction-to-fire classification when the profile is installed in regulated façade applications. Terminal product types include coextruded window main profiles, lineal cladding, soffit boards, fascia capping, and siding panels; dark capstock colours are limited to north-facing elevations in some fire-classified façade systems because surface temperatures above 60 °C can increase heat ageing and lower creep resistance.

Where heavy-gauge sheet is thermoformed into agricultural body panels, UNIBRITE® ASA UA-1300 is processed at 3.2 mm to 8.0 mm gauge because thinner sheet lacks impact at −30 °C and thicker sheet exceeds the heating capacity of infrared quartz ovens. The sheet is first produced on a vented single-screw extruder with L/D 30:1 to 32:1, screen changer and melt pump; pellets are dried at 80–85 °C for 4 h to 0.04 wt% moisture or below, and the melt temperature at the sheet die is held at 230–240 °C. Formulation is 100 phr UA-1300, 10–20 wt% reprocessed sheet skeleton regrind, and 1.5–3.0 wt% exterior-grade colour concentrate; light-coloured grades include 5–8 phr TiO₂, while black grades use 1–2 phr carbon black. The sheet is cut to blank size and thermoformed on a shuttle or rotary machine at a sheet surface temperature of 165–200 °C; the lower limit is set by stress whitening at sharp draw radii, and the upper limit by bubble formation at the sheet surface. Aluminium moulds are maintained at 60–80 °C with vacuum holes below 1.0 mm diameter to limit surface marking. A critical process conflict occurs when the sheet is heated above 200 °C for more than 120 s; the stabilizer package at the surface is consumed, and cross-machine shrinkage after demoulding exceeds 1.5%, causing edge lift against metal mounting frames. Compliance for the agricultural and construction segments is anchored to ISO 6603-2 for puncture impact, ISO 178 flexural modulus for panel stiffness, ISO 4892-2:2013 for weathering, and REACH Regulation (EC) No 1907/2006 for substances of very high concern. Terminal product types include tractor fender extensions, combine side shields, skid-steer cab roof covers, road sweeper side panels, and aftermarket utility vehicle body cladding.

Mower Hoods, Portable Genset Panels, and the Fuel-Weatherability Trade-Off

Outdoor power equipment components such as riding mower hoods, portable generator enclosures, pressure washer shrouds and garden machinery control boxes use UNIBRITE® ASA UA-1300 for the combination of UV resistance, low-temperature impact, and moderate chemical resistance. Compliance is driven by ISO 175:2010 chemical resistance testing for intermittent fuel splashes, ISO 4892-2:2013 for weathering, ISO 179-1/1eA for notched impact at −30 °C, and RoHS Directive 2011/65/EU Annex II where the equipment is classified as electrical. Formulation addition is 100 phr UA-1300, 1.0–2.5 wt% masstone colour masterbatch, 10–20 wt% regrind from recycled sprues, and 0.2–0.5 wt% external mould release where tool draft is below 1°; flame-retardant packages are not added because this grade is intended for non-ignition-facing panels unless separately certified. Injection moulding uses a melt temperature of 235–250 °C, mould temperature of 50–70 °C, compression ratio of 2.2:1 to 2.6:1, and a shot weight not exceeding 70% of barrel capacity; long thin hood surfaces require sequential valve gating to avoid knit lines that reduce tensile strength by more than 10% under ISO 527-2/1A/50. The operational boundary for fuel exposure is significant: intermittent splash contact with gasoline and ethanol blends up to E10 is generally acceptable for non-loaded surfaces, but continuous immersion in fuel, contact with brake fluid, or exposure to aromatic solvents is not recommended because stress cracking can occur at moulded-in stresses above 20 MPa; published data for UA-1300 under constant ethanol exposure at elevated temperature is limited, and qualification should include environmental stress cracking testing per ISO 22088-3 or ISO 22088-4. Terminal product types include riding mower hoods, portable generator side covers, pressure washer shrouds, garden tractor dash panels, and outdoor power equipment belt guards.