LG Chem ABS HI-140 is a high-impact acrylonitrile-butadiene-styrene moulding compound intended for injection-moulded components in which notched impact strength and low-temperature toughness are specified alongside conventional dimensional and aesthetic requirements. The material consists of a styrene-acrylonitrile copolymer continuous phase and a dispersed polybutadiene-rich rubber phase; this structure raises energy absorption during crack propagation compared with standard ABS while retaining melt processability on reciprocating-screw equipment. Representative supplier-published property data for injection-moulded specimens conditioned at 23 °C and 50 % relative humidity under ISO 291 are listed in Table 1.

The values in Table 1 should be interpreted as typical ranges for natural-grade injection-moulded specimens, not as lot-specific contractual minima. The notched Izod range of 25–35 kJ/m² at 23 °C is substantially above the 15–20 kJ/m² range commonly associated with general-purpose ABS, and the retention of 8–12 kJ/m² at −30 °C indicates a shift of the ductile-to-brittle transition toward lower service temperatures. This behaviour is directly relevant for snap-fit covers, screw bosses, and mounting lugs subjected to drop loading during assembly or service. The flexural modulus range of 2000–2200 MPa provides sufficient stiffness for structural housings, but designers should not select HI-140 as a load-bearing engineering polymer above approximately 85 °C because heat deflection temperature under 1.8 MPa load is in the 84–88 °C range.

How Does HI-140 Differ from General-Purpose and High-Heat ABS Grades?

Compared with general-purpose ABS, HI-140 shifts impact performance upward by increasing the rubber-phase contribution to crack-Blunting mechanisms. General-purpose ABS grades typically exhibit notched Izod values below 20 kJ/m² at 23 °C, whereas HI-140 remains in the 25–35 kJ/m² band under ASTM D256-23. The exact rubber-phase content and particle-size distribution are proprietary, but the practical consequence is that living hinges, snap fits, and moulded-in inserts are less likely to initiate brittle fracture during assembly. Melt volume-flow rate is retained at 16–20 cm³/10 min, which is intentionally lower than high-flow ABS grades above 25 cm³/10 min; this preserves impact strength because excessive melt-flow modification in ABS generally reduces molecular weight and low-temperature toughness.

High-heat ABS grades shift the heat deflection temperature upward, often above 95 °C under 1.8 MPa, but they can sacrifice melt flow and low-temperature impact. HI-140 is not a high-heat resin; its 84–88 °C HDT range places it in the standard ABS thermal class. Selection of HI-140 over a high-heat ABS should therefore be made only when the service environment does not require continuous dimensional stability above approximately 85 °C. Where chemical resistance to aromatic hydrocarbons, ketones, or esters is required, neither HI-140 nor general-purpose ABS is generally sufficient; styrenic copolymers, ASA, or PC/ABS may be more appropriate depending on the stress state and exposure duration.

Injection-moulded applications for HI-140 are concentrated in small appliance housings, power-tool shells, vacuum cleaner bodies, automotive interior trim, and electrical enclosures. Selection is commonly driven by the need for crack resistance around moulded-in inserts and snap joints; for electrical enclosures, a UL 94 HB classification at 3.0 mm wall thickness is typical for non-flame-retardant ABS. Where the end-use standard is IEC 62368-1 or IEC 61010-1, the enclosure impact test is usually conducted on finished parts at the minimum specified wall thickness; moulded-part performance can be influenced by gate location, weld lines, and orientation. Published data for this specific configuration are limited, so component-level testing is required when impact performance is safety-critical.

Thermal and Rheological Boundaries for Injection Moulding

Predrying is an operational boundary, not a recommendation, at ambient relative humidity above 60 %. The resin should be dried in a desiccant-wheel or dehumidifying hopper dryer with a dew point of −30 °C or lower at 80 °C for 2–4 h. Maximum residual moisture before melt processing is <0.02 wt%; higher moisture produces silver streaks, splay, unstable shot weight, and surface defects. The drying time should be extended when bulk storage containers are opened in high-humidity conditions or when regrind is introduced without separate drying.

Melt temperature should be maintained between 220 °C and 240 °C, with barrel zones staged from rear to front at approximately 200–210 °C, 210–220 °C, and 220–230 °C. The nozzle should be held at 220–240 °C. Mould temperature is normally controlled between 30 °C and 60 °C; lower mould temperatures improve surface gloss and cycle time, while higher mould temperatures improve weld-line strength and dimensional stability. Prolonged residence time above 260 °C should be avoided because butadiene rubber undergoes thermal oxidation, producing yellowing, brown streaks, carbon specks, and loss of notched impact.

Regrind incorporation up to 20 wt% is common on production lines, but repeat heat history causes measurable decline in notched Izod impact; moulders should re-qualify impact-critical parts when regrind content exceeds this level. Dedicated purging with acrylic, HDPE, or ABS-based purge compound is preferred. Avoid purging with polyoxymethylene because residual POM releases formaldehyde and can create surface voids or odour. PVC contamination in regrind should be excluded because hydrochloric acid generated from PVC degradation attacks the ABS backbone and accelerates embrittlement.

When HI-140 Is Used in Thin-Wall Electrical Housings and Automotive Interior Trims

In thin-wall electrical housings with nominal wall thickness of 2.0–2.5 mm, mould-filling is controlled by melt temperature and injection speed rather than holding pressure alone. Published spiral flow data for this specific grade are limited; therefore, mould-filling simulation should be calibrated against capillary rheometry or in-mould pressure sensors instead of relying on the single-point melt volume-flow rate of 16–20 cm³/10 min. Weld-line impact strength is lower than bulk notched Izod because the rubber particles are not effective across the weld plane; when a gate system produces weld lines in a drop-impact area, mould temperature should be increased to 50–60 °C and gate dimensions should be enlarged to promote molecular diffusion at the weld interface.

For automotive interior trim such as door map pockets and centre console side covers, low-temperature impact retention at −30 °C is important but surface scratch resistance is limited relative to high-heat ABS or ASA. Pencil hardness measured under ISO 15184 is typically lower than that of higher-heat styrenic grades; textured surfaces and graining are commonly specified to manage visible scuffing. Dimensional control uses the 0.4–0.7 % mould shrinkage range from ISO 294-4; toolmakers should apply this range to both free and constrained shrinkage regions, and critical snap-fit dimensions should be verified after 24 h post-moulding conditioning because shrinkage continues after demoulding.

Chemical exposure limits the use of HI-140 in parts that contact aromatic hydrocarbons, ketones, esters, or chlorinated solvents; these solvents induce environmental stress cracking in loaded ABS components. Dilute aqueous cleaners and aliphatic hydrocarbons are generally less aggressive, but compatibility testing under ASTM D543 at the actual stress state is required for critical applications. Regulatory compliance is not inherent to the base resin; RoHS Directive 2011/65/EU, REACH SVHC, and food-contact clearances such as FDA 21 CFR 180.22 or (EU) No 10/2011 must be confirmed with the supplier for the specific lot and colour concentrate combination.