LG Chem ABS AT-560 is an unfilled acrylonitrile-butadiene-styrene copolymer supplied for injection moulding. The grade belongs to the manufacturer’s AT-series, which is directed toward automotive trim and technical mouldings where melt processability and impact retention must be held in a controlled balance. The material consists of a styrene-acrylonitrile continuous phase and grafted polybutadiene rubber domains; the rubber domains contribute low-temperature ductility, and the SAN matrix contributes stiffness, surface hardness, and chemical resistance. The resin is typically supplied as natural or colour-compounded pellets, and the lot certificate of analysis remains the controlling document because colourants and additives shift melt flow, notched impact, and mould shrinkage. Under ISO 1183-1, the density of the natural grade is normally 1.04–1.06 g/cm³. The melt mass-flow rate measured under ISO 1133-1:2022 at 220 °C/10 kg is specified by the supplier and for this series commonly falls within 15–30 g/10 min. The unfilled grade is not a flame-retardant ABS; it typically carries UL 94 HB at 1.5 mm. These values are adequate for initial material-balance and capacity calculations but do not replace grade-specific data from the current datasheet.

Regulatory conformity is governed by the supplier’s safety data sheet and lot-specific declarations. The unfilled AT-560 grade is generally supplied in accordance with EU REACH Regulation (EC) No 1907/2006 and EU RoHS Directive 2011/65/EU for the six restricted substances: lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ethers. Food-contact status under EU Regulation (EU) No 10/2011 is not automatic for automotive-grade ABS; if the part is used in food-contact or potable-water service, migration testing under the applicable food-contact standard should be performed.

What Injection Moulding Parameters Govern AT-560 Processing?

Moisture control is the first critical parameter. ABS is hygroscopic enough to produce splay, silver streaking, and surface blisters when residual moisture exceeds 0.05 wt% at the hopper. The resin should be dried in a desiccant dryer with a dew point at or below -30 °C at 80–90 °C for 2–4 h. When ambient relative humidity exceeds 60%, drying should be extended to 4–6 h or the machine hopper maintained under dry air. Moisture content should be verified by ISO 15512:2019 or a calibrated moisture balance; wet pellets are a common cause of lot rejection when colour streaks appear after moulding. The barrel temperature profile for a general-purpose screw with 20:1–24:1 L/D is rear 190–210 °C, centre 210–230 °C, front 220–240 °C, and nozzle 220–230 °C. Melt temperature from an air shot should be 220–250 °C, with an upper limit of 260 °C.

Thermo-oxidative degradation of the polybutadiene phase accelerates above that threshold, producing brown streaks, gloss shifts, and notched impact loss. Residence time at 240 °C should not exceed 8 min; above 250 °C, residence time should be kept below 5 min. Shot size should be 50–70% of the barrel capacity to limit residence time. Screw compression ratio should be 2.0:1–2.5:1, and back pressure should be limited to 1–5 bar unless colour dispersion requires higher shear. An open nozzle is preferred; long shut-off nozzles or hot-runner dead spots increase the likelihood of stagnant material degradation. Hot-runner manifolds should be externally heated and free of sharp corners, with manifold temperatures within 220–240 °C.

Mould temperature controls surface gloss and weld-line strength. A mould temperature of 40–60 °C is preferred for high-gloss automotive trim; temperatures below 30 °C can generate flow lines, jetting, and weak weld lines in thin sections. Injection speed should be set to fill 95–98% of cavity volume before switchover to holding pressure, with hold pressure at 50–70% of peak injection pressure. Injection pressure should be adjusted to maintain consistent shear rates; excessive pressure at the gate can create jetting and surface defects. Venting at the perimeter of the cavity should be 0.02–0.03 mm for unfilled ABS. Clamp force is calculated from the projected area and cavity pressure; for thin-wall components with wall stock 0.8–1.5 mm, cavity pressure at the end of fill commonly falls in the 30–50 MPa range. For thicker sections above 2.5 mm, sink marks should be controlled by packing pressure and gate location rather than by excessive mould temperature.

Gate position and number are determined by flow length and weld-line location. For unfilled ABS, flow length at 1.5 mm wall and 230 °C melt temperature can exceed 100–150 mm under moderate pressure; thinner sections 0.8 mm may require multiple gates or higher injection speed. Fan gates, tab gates, and subgates are acceptable; direct sprue gating can produce high local stress and should be limited to centre-gated knobs or circular parts. Weld lines should be placed away from impact-loaded bosses and snap-fit features because notched impact at a knit line can be 30–50% lower than bulk material.

The following representative property envelope is compiled from LG Chem ABS technical literature for the AT-series and should be confirmed against the current product data sheet for AT-560.

These values are not specification limits. The supplier’s certificate of analysis for each lot controls the actual melt flow rate, impact strength, moisture content, and shrink. Coloured or custom-compounded versions may differ from the natural resin data; ultraviolet stabilisation, antistatic additives, or flame-retardant packages alter viscosity and mechanical properties.

Comparative Position Against General-Purpose and High-Heat ABS Grades

The primary distinction of AT-560 relative to general-purpose ABS is the balance between melt flow and room-temperature impact. General-purpose ABS grades may display lower melt mass-flow rates, often in the 8–20 g/10 min band, increasing filling pressure in long thin-wall flow paths but retaining slightly higher notched impact and heat deflection. High-heat ABS grades can extend HDT to 95–110 °C, but melt flow typically falls to 5–15 g/10 min, requiring higher barrel temperatures and more gate pressure. AT-560 occupies the middle ground for automotive interior and appliance housings where processability at moderate tool temperatures is more important than continuous service above 90 °C. The lower melt temperature relative to high-heat ABS also reduces energy input and shortens cycle time.

The comparison is based on class-level data; individual grade data must be taken from the manufacturer’s current datasheet before material substitution.

In electrical and electronics housings, AT-560 is commonly evaluated for wireways, terminal covers, and small appliance chassis. Because the unfilled grade is not inherently flame-retardant, the enclosure design must either operate below the ignition resistance threshold or specify a flame-retardant ABS grade. Surface resistivity is typical of unfilled ABS, generally above 10¹³ Ω under IEC 62631-3-1; the material does not provide an antistatic or static-dissipative function unless a conductive filler is compounded. Comparative tracking index for unfilled ABS is commonly reported in the 400–600 V range under IEC 60112, which is relevant for live-part separation. The material is not recommended for direct outdoor exposure without ultraviolet stabilisation because ABS degrades under UV; weatherable ASA or UV-stabilised ABS should be selected for exterior components tested under ISO 4892-2.

When AT-560 Is Evaluated as a Replacement for PC/ABS in Thin-Wall Housings

When evaluating AT-560 as a replacement for PC/ABS in non-structural thin-wall housings, the service temperature, impact load, and chemical exposure must be reviewed. PC/ABS typically provides HDT at 1.80 MPa in the 105–125 °C range and notched Izod impact at 23 °C in the 35–60 kJ/m² range, while the ABS grade is constrained to 80–90 °C HDT and 15–30 kJ/m² notched Izod impact under the same test standards. The substitution becomes viable when the housing wall thickness is below 1.5 mm and the dominant design requirement is filling pressure rather than elevated-temperature load. AT-560 also has lower density, 1.04–1.06 g/cm³, compared with 1.12–1.16 g/cm³ for PC/ABS, which can reduce part mass but also reduces stiffness and creep resistance. The melt temperature for AT-560 can be held at 230–245 °C, avoiding the 260–280 °C melt temperatures common for PC/ABS and reducing thermal stress on colourants and additives. However, the ABS grade is less resistant to aromatic hydrocarbons, ketones, and esters than PC/ABS; chemical contact should be limited to diluted aqueous solutions, alcohols, or aliphatic hydrocarbons unless testing under ISO 175 demonstrates acceptable retention of tensile properties.

Low-temperature impact must also be verified. PC/ABS retains higher ductility at -30 °C, while unfilled ABS notched impact falls sharply below 0 °C. For enclosures that may be dropped or struck at subzero temperatures, a PC/ABS or high-impact ABS grade may be required. If AT-560 is selected, gate position should be placed away from impact-loaded bosses, and knit lines should be tested under ISO 179/1eA or ISO 180/A on tooled specimens rather than on edge-gated plaques.

Chemical resistance data for unfilled ABS should be generated under ISO 175:2010 or ISO 22088-3 for environmental stress cracking. The SAN matrix is resistant to dilute aqueous solutions, aliphatic hydrocarbons, and alcohols under short-term contact but is attacked by ketones, esters, chlorinated solvents, aromatic hydrocarbons, and concentrated acids. Stress cracking can occur when external stress and chemical exposure overlap; parts under load should not be wiped with solvent-based cleaners. For applications that require repeated cleaning with disinfectants or hydrocarbon-based oils, contact testing should be performed at the upper service temperature to verify tensile property retention. The unfilled grade has no ionic corrosion risk but can exhibit surface haze after prolonged hot-water contact above 60 °C.

Continuous heat exposure is bounded by the heat deflection temperature. For unfilled ABS, dry-heat ageing above 80–90 °C can cause colour shift, gloss loss, and embrittlement as the butadiene phase oxidises. Short-term excursions to 100 °C may be tolerated for limited hold times in automotive paint ovens, but the part should be unsupported because creep modulus falls with temperature. Long-term service at 60–80 °C is generally acceptable for interior trim; above this range, a high-heat ABS, ASA, or PC/ABS grade should be selected. Thermal ageing validation should be based on ISO 178:2019 flexural modulus retention and ISO 180/A impact retention after oven ageing, not solely on visual inspection.

Evaluating Lot-to-Lot Variation Through Melt Flow and Impact Data

Batch-to-batch consistency in an injection-moulding supply chain is best monitored through melt flow rate and notched impact testing. A shift in melt mass-flow rate of more than ±2 g/10 min from the approved lot reference can change fill pressure in thin-wall tools and alter the position of the switchover point. In production-scale moulding of ABS with wall sections below 1.2 mm, melt flow variability is more likely to produce short shots or flash than tensile strength variation. Notched Izod impact testing under ISO 180/A at 23 °C and -30 °C provides a second control point; a drop of more than 3 kJ/m² at low temperature should trigger a review of rubber-phase dispersion and regrind level. Tensile stress at yield under ISO 527-2:2012 and flexural modulus under ISO 178:2019 are less sensitive to minor lot variation but are useful for annual material qualification. The melt volume-flow rate under ISO 1133-1:2022 can also be used to detect contamination with polycarbonate or other high-melt-temperature resins during changeover; mixed feedstocks often show unstable melt flow and visible streaking.

Surface appearance of moulded AT-560 parts depends on mould temperature, polish, and fill velocity. High-gloss automotive trim requires mould steel polished to SPI A-1 finish and mould temperature at the upper end of 50–60 °C. Mould temperature too low creates melt-flow lines; too high can increase cycle time but improves gloss replication and knit-line appearance. For textured surfaces, the draft angle should be increased by 1–2° over polished surfaces to allow release from the rubbery ABS melt. Mould shrinkage should be measured after conditioning at 23 °C and 50% RH for 24 h. Annealing at 70–80 °C for 1–2 h may reduce moulded-in stress but can increase shrinkage; it should be validated on production tooling.

For automotive interior parts, volatile organic compound and fogging behaviour are specified by vehicle manufacturers. The supplier may provide thermal desorption or fogging data under ISO 6452 and VDA 278. AT-560 should be evaluated in the finished part configuration because moulding temperature, residence time, and colourant package influence emissions. Lower melt temperatures and short residence times generally reduce low-molecular-weight degradation products. Published data for the specific absorbed-compound configuration is limited, so part-level validation remains necessary.

Post-industrial regrind from AT-560 mouldings can be re-used at 10–30 wt% when the regrind is clean, dried, and free of degraded material. Higher regrind fractions reduce notched impact and increase the risk of black specks. Purging between colours or from ABS to another polymer should use a polystyrene or SAN-based purge compound at 230–250 °C; purging at temperatures above 260 °C can carbonise butadiene residues. Tools should be cleaned with mild alkaline aqueous solutions and not with chlorinated solvents, which can attack ABS and cause stress cracking. For parts requiring tight dimensional stability, post-mould shrinkage should be accounted for under ISO 294-4:2018; annealing is not normally required for unfilled ABS but may be used at 70–80 °C for 1–2 h to relieve moulded-in stress when dimensional checks show excessive movement.