LG Chem ABS HI-1210 is an acrylonitrile-butadiene-styrene copolymer supplied as injection-molding pellets. The grade is positioned for applications that require a balance of room-temperature notched Izod impact, moderate melt flow, and moderate heat resistance. Typical density at 23°C is 1.04 g/cm³ when tested under ASTM D792. Supplier-published melt volume-flow rate under ISO 1133-1:2022 at 220°C with 10 kg load is approximately 13–14 cm³/10 min. The unreinforced tensile modulus remains below 2.5 GPa; therefore HI-1210 is not a direct substitute for glass-filled nylon, polycarbonate, or other engineering resins in load-bearing components. Published data for high-speed multi-axial impact of this specific grade is limited, and energy-management parts should be tested under ASTM D3763 using production-molded plaques. The material is commonly supplied in natural or black; custom color concentrates may be introduced at the press. Material handling and drying procedures directly influence surface quality and mechanical consistency, particularly in humid environments.

The impact response of HI-1210 arises from dispersed polybutadiene rubber particles grafted with styrene-acrylonitrile copolymer. This phase arrangement increases energy absorption during crack initiation but reduces modulus, hardness, and resistance to organic solvents compared with unmodified SAN. The rubber phase is thermally sensitive; prolonged residence time at elevated temperatures can crosslink or degrade the polybutadiene domains and lower notched Izod impact. Consequently, melt temperature control is more critical than for unreinforced polystyrene or SAN. Low-temperature impact is less robust than at room temperature; below -20°C, notched impact values fall, and the ductile-to-brittle transition must be evaluated under ASTM D256 at the intended service temperature. Outdoor unpainted service is limited by ABS weathering behavior; UV exposure induces yellowing and surface gloss loss. For exterior parts, painted ABS, UV-stabilized ASA, or AES grades are preferred.

What Distinguishes This Grade from General-Purpose and Flame-Retardant ABS?

Relative to medium-impact general-purpose ABS used in thin-wall appliance parts, HI-1210 shifts the fracture response toward higher room-temperature notched Izod impact while retaining melt flow within a range compatible with standard injection molds. The dispersed rubber phase is the controlling variable: higher butadiene content increases notch toughness but reduces flexural modulus and surface hardness. A flame-retardant ABS rated V-0 under UL 94 at 3.0 mm typically contains halogenated or phosphorus-based additives; these additives raise melt viscosity, lower notched Izod impact, and can corrode tooling if processing temperatures are excessive. HI-1210 is generally classified HB under UL 94 at 3.0 mm; it is not suitable for enclosures requiring V-0 at 1.5 mm or 2.0 mm. When converting from a flame-retardant ABS to HI-1210, tooling should be checked for shrinkage differences and the part must be revalidated for flammability compliance.

Within the ABS HI series, it is not valid to infer a linear relationship between the numerical grade suffix and impact performance. Different grades may be optimized for high flow, heat resistance, low gloss, or electroplating. Direct comparison must use identical specimen thickness, conditioning, and test standard because notched Izod values vary with notch radius and moisture state. Grades with higher melt flow generally exhibit lower impact toughness, while grades with higher Vicat softening normally sacrifice processability.

The following supplier-published typical values are not design limits and should be verified against the certificate of analysis for the production lot.

Processing Boundaries Observed on Injection Molding Lines

Pre-drying must reduce residual moisture below 0.1 % by weight. Desiccant drying at 80°C for 2–4 h is conventional for fresh material. A closed-loop desiccant dryer with a dew point at or below -20°C is preferred. At ambient relative humidity above 60%, open hoppers allow rapid moisture uptake; this produces splay, silver streaks, and reduced surface quality. Moisture levels above 0.15 % are particularly visible at melt temperatures near 240°C, where water vapor expands at the flow front and interrupts the surface morphology.

The nozzle melt-temperature window is 200–240°C. Below 200°C, high melt viscosity promotes short shots in wall sections thinner than 2.0 mm and weakens weld lines at converging flow fronts. Above 240°C, the polybutadiene phase undergoes thermal-oxidative degradation, producing brown specks, yellowing, and a measurable reduction in notched Izod impact. The optimum set point for many tools is 220°C with a mold temperature between 30°C and 60°C. Higher mold temperatures improve surface gloss and weld-line strength but increase cycle time and may increase molded-in stress after cooling. Low mold temperatures below 30°C increase frozen-in orientation and cause post-molding dimensional drift.

A general-purpose screw with L/D between 20:1 and 24:1 and compression ratio 2.5:1–3:1 is adequate. Back pressure should be limited to 0.5–1.5 MPa for homogeneous melt without excessive shear heating. Screw rotation speed of 50–100 rpm is typical for medium-size machines; higher speeds reduce melt viscosity through shear heating but can degrade the rubber phase. Injection speed should be moderate to high for thin-wall filling, but excessive velocity may cause jetting, silver streaks, and gate blush. Residual melt cushion of 3–5 mm and controlled decompression after recovery are used to prevent drool and gate stringing.

Regrind may be used if clean, dry, and free of surface contamination. Published supplier guidance for this specific grade is limited; a conservative production limit of 20% regrind is often applied with notched impact data checked on first-run parts. Higher levels increase variability in melt flow and color shift.

When Moisture Content Exceeds 0.1%

Splay defects are often misdiagnosed as injection-speed or gate-size problems. The first check should be residual moisture. If splay appears at normal melt temperatures, re-dry at 80°C for 4 h and verify dryer dew point. Do not raise melt temperature above 240°C to burn off moisture; this accelerates degradation of the butadiene phase and increases dark specks. In high-humidity regions, use hopper loading with a dry-air purge and minimize hopper residence time. A moisture analyzer using loss-on-drying at 105°C can be used to track moisture before molding.

Electrical housing parts molded from HI-1210 are typically rated HB under UL 94 at 3.0 mm. If the enclosure specification includes V-0 at 1.5 mm or 2.0 mm, conversion to a flame-retardant ABS must be revalidated for flame penetration and mechanical integrity after heat aging. The supplier-reported mold shrinkage of 0.4–0.7 % under ASTM D955 is a range for specified plaque geometry; actual shrinkage varies with gate size, hold pressure, wall thickness, and mold temperature. Multi-cavity tool compensation should be based on a dimensional capability study on the intended press, not on catalog values.

For decorative electroplating, the polybutadiene particle-size distribution and bulk rubber content control chromic acid etch pit morphology. Published data for HI-1210 under chromic acid etch protocols is limited, and a dedicated electroplating ABS generally provides more consistent adhesion. If plating is specified, adhesion testing under ASTM B533 or the applicable OEM standard should be performed on production-molded plaques. For painting, surface compatibility depends on mold release residues and texture; low-molecular-weight silicone release agents may interfere with topcoat adhesion unless removed by a validated cleaning process.

During cleaning and service, contact with ketones, esters, and chlorinated hydrocarbons should be avoided. These solvents attack the styrene-acrylonitrile matrix and cause environmental stress cracking, especially at sharp corners, weld lines, and molded-in stress concentrations. Aromatic hydrocarbons can cause swelling and surface tack. When switching from higher-temperature engineering resins to HI-1210, purge with acrylic or general-purpose ABS; residual ABS exposed to temperatures above 260°C during later high-temperature runs may degrade and produce black specks. For long production interruptions, reduce barrel temperatures to 150°C or purge to prevent stagnation degradation.