LG Chem ABS RS-600 is an unfilled acrylonitrile-butadiene-styrene resin supplied for injection moulding and selected extrusion applications. The grade is designated within the ISO 2580-1 styrene-acrylonitrile copolymer system as a modified thermoplastic containing a dispersed polybutadiene rubber phase grafted with styrene-acrylonitrile copolymer. The rubber phase contributes impact strength through crazing and shear yielding, while the continuous SAN phase provides rigidity, chemical resistance, and dimensional stability. The resin is supplied as natural-colour pellets and is normally combined with colour masterbatch at the moulding machine, although pre-compounded colours may be available through approved compounding channels. Density of the unfilled material is typically reported as 1.05 g/cm³ when tested according to ISO 1183-1. Melt viscosity is positioned in the medium-to-high flow segment for ABS; the melt volume-flow rate is commonly stated as 55 cm³/10 min at 220 °C under a 10.0 kg load using ISO 1133-1. Typical room-temperature mechanical values include a tensile stress at yield of 44 MPa under ISO 527-2, a flexural modulus of 2300 MPa under ISO 178, and a notched Izod impact strength of 18 kJ/m² at 23 °C under ISO 180/A. Low-temperature notched Izod impact is reported near 8 kJ/m² at -30 °C, which is a relevant boundary for freezer and cold-climate components. Thermal performance is typically characterised by a Vicat softening temperature of 95 °C under ISO 306/B50 and a heat deflection temperature of 88 °C at 1.8 MPa using ISO 75-2/A. Mould shrinkage is generally observed in the range of 0.4 % to 0.7 % when measured on ISO 294-4 plaques, although gate geometry, holding pressure, and wall thickness produce measurable batch-to-batch and tool-to-tool variation. Published data for this specific configuration is limited; the values above should be verified against the current manufacturer’s certificate of analysis and product datasheet before tool design or part qualification.

What Rheological and Mechanical Properties Define RS-600 in Injection Moulding?

Because the grade is intended for large-area and moderately thin-walled mouldings, flow length and pressure drop are more informative than single-point melt-flow index. Spiral-flow testing on production tooling has shown that RS-600 fills wall sections down to approximately 1.2 mm at a melt temperature of 240 °C and a mould temperature of 40 °C, provided the gate diameter is not less than 0.8 mm. Above 260 °C, the butadiene phase begins to show thermal degradation, producing silver streaks and brown discoloration at the gate area. The practical upper melt-temperature boundary is therefore 250 °C for continuous operation. Notched impact retention depends on rubber-particle crosslinking and grafting efficiency. In RS-600, the notched Izod value at 23 °C is lower than that of high-impact extrusion grades but higher than many high-flow styrene-acrylonitrile copolymers. This positions the material for internal structural brackets, appliance housings, and electrical enclosures where thin-wall flow is required but the part is not subjected to repeated high-energy impact at sub-zero temperatures. Notched impact testing according to ISO 180/A indicates that dry-as-moulded parts retain approximately 70 % of their room-temperature impact once the mould temperature is lowered from 60 °C to 30 °C; processors balancing gloss and toughness therefore maintain mould temperature above 40 °C for cosmetic surfaces. Flexural modulus is comparatively linear at low strain, and the grade does not exhibit yield-point drop that would produce gross dimensional instability during ejection. The tensile strain at yield is typically 2.5 % under ISO 527-2. For parts requiring snap-fit engagement, the allowable strain should be kept below the yield strain with a safety factor of at least 1.5; repeated snap-fit deflection beyond yield can produce stress whitening at the hinge boss and eventual crack initiation along the flow-weld line. Pre-drying is the first processing control applied to RS-600. Residual moisture above 0.05 % produces splay, gate-area haze, and reduced surface gloss in moulded parts. The resin should be dried in a desiccant dryer at 80 °C for 2 h to 4 h, with a dew point of ≤ -40 °C and sufficient airflow to reach the hopper residence time. Hopper capacity should be matched to shot weight so that dried material is not held at temperature for more than 8 h; prolonged residence can shift the rubber-phase morphology and reduce notched impact. Barrel temperature profiles on a general-purpose screw with an L/D ratio of 20:1 to 24:1 are typically set from 200 °C at the rear zone to 240 °C at the nozzle. Back pressure is held at 5–10 bar and screw speed is limited to 30–60 rpm to avoid viscous heating. Injection speed is set from medium to high for thin-wall fill, but excessively high speed increases shear heating at the gate and can create jetting on untextured surfaces. Hold pressure is normally 50–70 MPa, with hold time adjusted to gate freeze; for a 2.0 mm wall and a 1.0 mm gate, gate freeze is typically reached in 3–6 s. On production machines with clamp forces from 80 t to 180 t, observed bottle-neck failures are more frequently caused by inadequate drying or excessive regrind than by melt-temperature variation. Regrind addition up to 20 wt% is generally tolerated when the regrind is dried and free of dust; higher regrind levels lower melt viscosity and notched impact, and increase the visual occurrence of black specks from degraded rubber particles. Vented-barrel machines are not required, but hopper magnet and screen pack filtration of regrind are recommended for thin-wall cosmetic parts.

When Thin-Wall Housings Require a Balance of Melt Flow and Envelope Stability

When wall thickness falls below 2.0 mm, the limiting processing variable is not melt pressure but frozen-layer formation at the mould wall. RS-600 has sufficient melt-flow to fill a 1.5 mm wall over a length of 200 mm from a centre gate when the mould temperature is 45 °C and the melt temperature is 245 °C. The flow front remains coherent at linear speeds above 150 mm/s, but lower injection speeds produce premature freezing and weld-line weakness where opposing fronts meet. Weld-line impact strength can be 40–50 % lower than that of the bulk material, which is a critical design boundary for snap-fit features located downstream of holes and ribs. For electronic enclosures and refrigerator display trims, the material is processed with negative draft allowance no greater than 0.5° on textured surfaces to avoid ejection damage. Textured mould surfaces increase the effective coefficient of friction and require additional draft or ejection force. Parts ejected above 80 °C may show dimensional instability after cooling; the ejector plate should therefore be sequenced with sufficient cooling time to reduce part-surface temperature below 70 °C. Thermal cycling between -20 °C and 60 °C on assembled enclosures produces differential expansion between ABS and metal inserts; design clearance around inserts should be at least 0.1 mm per 100 mm of insert length. Regulatory assessments for RS-600 are normally based on the current RoHS Directive 2011/65/EU Annex II and REACH Regulation (EC) No 1907/2006 SVHC Candidate List. For the standard unpigmented grade, lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ethers are not intentionally added; laboratory verification uses IEC 62321 methods. The material is typically classified as UL 94 HB at 1.6 mm, and the manufacturer’s yellow-card listing should be referenced for the exact colour and thickness.

Requirement	Assessment	Standard or method
RoHS 2011/65/EU, Annex II	No intentionally added restricted substances	IEC 62321-5 to IEC 62321-8
REACH SVHC	Not intentionally added	ECHA Candidate List
Flammability	Typical classification HB	UL 94
Melt volume-flow rate	Nominal 55 cm³/10 min	ISO 1133-1
Density	Typical 1.05 g/cm³	ISO 1183-1

Food-contact suitability of RS-600 is not automatically established by a resin designation alone. Finished articles intended for repeated food-contact use must be evaluated for composition, surface-to-volume ratio, temperature, and time under the applicable regulatory framework. Published data for this specific configuration is limited, and manufacturer confirmation is required before food-contact claims are made. The grade is not recommended for medical implant applications or for parts exposed to strong oxidising acids, ketones, or aromatic solvents; immersion in methyl ethyl ketone can cause swelling and loss of load-bearing properties within minutes.

Comparative Placement Against High-Impact, High-Gloss and Plating ABS Grades

The main structural difference between RS-600 and high-impact ABS grades such as HI-121H lies in the balance between melt flow and rubber-phase content. High-impact grades typically show lower melt volume-flow rate and higher notched Izod impact, sometimes above 25 kJ/m² at 23 °C, but they require higher melt temperature and injection pressure to fill thin-wall sections. RS-600 sacrifices a portion of that impact reserve for better flow length and lower internal stress in complex mouldings. For parts with wall thickness above 3.0 mm and impact exposure at sub-zero temperatures, a high-impact grade remains the lower-risk selection. Compared with high-gloss ABS grades that use smaller rubber particles, higher methyl methacrylate content, or surface-lubricated formulations, RS-600 exhibits lower specular gloss but better retention of mechanical properties after thermal ageing. Gloss readings on polished tools are typically lower than high-gloss grades because the dispersed rubber particles cause micro-scale surface roughness after ejection. The result is a matte-to-satin appearance that hides fingerprint marks and minor sink marks, which is often specified for control panels and appliance bodies where light reflectance is secondary to dimensional repeatability. Against electroplating ABS grades, RS-600 does not provide the tailored butadiene particle-size distribution and etchable rubber morphology required for uniform palladium-tin activation in chromic acid etching. Plating adhesion on RS-600 is generally lower and less reproducible; surface roughness after etching varies with local rubber-particle density. Chrome-plated decorative mouldings should therefore use a dedicated plating grade. RS-600 is better suited to non-plated structural and trim components, painted applications where solvent adhesion is controlled by surface treatment, or parts with in-mould labelling.