ABS is sold in grade families rather than a fixed number of types: general-purpose, high-impact, high-flow, heat-resistant, flame-retardant, plating, UV-stabilized, transparent and filled grades, many of them in injection and extrusion versions, plus blends with polycarbonate, nylon and other polymers. Each family is the same acrylonitrile-butadiene-styrene base tuned for one property, usually at some cost to another.
No standard fixes the list. A type is a position on datasheet numbers such as Vicat softening temperature, melt mass-flow rate and Charpy notched impact strength, so the datasheet value and its test condition matter more than the label on an offer. The values below are typical values for named grades, not limits for the type.
Types of ABS by Property
Producers make one type of ABS differ from another by changing one of four things:
- The rubber phase: more polybutadiene, or rubber particles of a different size and structure, raises impact strength.
- The matrix: the molecular weight and acrylonitrile content of the styrene-acrylonitrile matrix move flow, stiffness and chemical resistance.
- A third monomer: alpha-methylstyrene raises heat resistance, and methyl methacrylate makes the material transparent.
- Additives and fillers: flame retardants, UV stabilizers, glass or carbon fiber and conductive fillers add a property the base polymer lacks.
Food-contact suitability is a regulatory status that a specific grade either has or lacks. In the US, 21 CFR 181.32 permits ABS with less than 30 percent acrylonitrile in films and coatings, and in rigid containers only as piping for food products and repeated-use articles, subject to limits on extractable acrylonitrile monomer.
General-Purpose ABS
General-purpose ABS is the balanced grade that sets the baseline for every other type: medium flow, good impact and heat resistance, molded into appliance housings, household goods, toys and automotive parts. INEOS Styrolution’s Terluran GP-22 has a melt volume rate of 19 cm³/10 min at 220 °C/10 kg and a notched Izod impact strength of 26 kJ/m² (ISO 180/A, 23 °C).
High-Impact ABS
High-impact ABS is a grade whose butadiene rubber phase is built up for toughness, so it absorbs more energy before it cracks, most of all below freezing. Terluran HI-10 has a notched Izod impact strength of 36 kJ/m² at 23 °C against 26 kJ/m² for GP-22, and 14 against 8 kJ/m² at −30 °C, both by ISO 180/A.
The toughness costs stiffness and flow. Terluran HI-10’s tensile modulus is 1,900 MPa against 2,300 MPa for GP-22, and its melt volume rate is 5.5 against 19 cm³/10 min at 220 °C/10 kg. HI-10 is also sold for extrusion and blow molding, processes that work with its low flow.
High-Flow ABS
High-flow ABS is a grade with a higher melt flow, made for thin walls and long flow lengths such as telecom and electronics housings. Terluran GP-35 has a melt volume rate of 34 cm³/10 min at 220 °C/10 kg against 19 for GP-22, at some loss of impact: GP-35’s notched Izod impact strength is 22 kJ/m² against 26 kJ/m² for GP-22 (ISO 180/A, 23 °C).
Heat-Resistant ABS
Heat-resistant ABS raises the heat deflection temperature a few degrees above general-purpose grades, enough for automotive lamp housings, mirror housings and exterior trim. In INEOS Styrolution’s Novodur High Heat grades, the heat deflection temperature at 1.8 MPa runs 99–102 °C, against 94 °C for the general-purpose Terluran GP-22 under the same annealed test.
The Novodur High Heat grades, like GP-22, read higher at 0.45 MPa and on Vicat B/50 than at 1.8 MPa, so a heat figure quoted without its load cannot be compared with one that has it.
Against GP-22, the Novodur High Heat grades are lower in both toughness and flow. Their notched Charpy impact strength is 11–18 kJ/m² against 22 kJ/m² for GP-22 (ISO 179/1eA, 23 °C), and their melt volume rates are 5.5–9.5 against 19 cm³/10 min at 220 °C/10 kg.
Flame-Retardant ABS
Flame-retardant ABS is compounded with flame-retardant additives so that molded parts reach a UL 94 vertical-burn class, a common requirement on electrical and electronic housings. The class belongs to a thickness: Chi Mei’s POLYLAC PA-765 is rated V-1 at 1.0 mm, V-0 at 1.5 mm and 5VA at 2.5 mm. Check that the rated thickness is at or below the thinnest wall of the part.
Plating-Grade ABS
Plating-grade ABS is ABS made and sold for electroplating, for chrome-finished parts such as automotive trim and sanitary fittings. A plating grade is qualified by the producer’s electroplating listing and by trials on the plating line rather than by a datasheet number.
UV-Stabilized ABS
UV-stabilized ABS is ABS compounded with UV absorbers and hindered-amine light stabilizers to slow the yellowing, chalking and loss of impact strength that sunlight causes in the butadiene rubber phase.
For parts that stay outdoors for years, the usual choice is ASA, which uses an acrylate rubber in place of butadiene. UV protection can also be added at the press through a UV masterbatch when the base grade carries none.
Transparent ABS
Transparent ABS is MABS: methyl methacrylate is copolymerized into the ABS structure so the matrix and rubber phase match in refractive index and light passes through without scattering at the rubber particles. INEOS’s Terlux 2802 transmits 89% of light at 550 nm with haze below 3%, both by ASTM D 1003.
Filled ABS
Filled ABS is ABS compounded with glass fiber, carbon fiber, glass beads or conductive fillers to raise stiffness or control static. Glass-fiber ABS grades on producers’ lists run from 4% glass (INEOS’s ABS-GF4 grades) to 40% (RTP Company’s glass-fiber ABS).
Glass raises stiffness and cuts toughness. INEOS’s Novodur P2HGV, at 16.5% glass fiber, has a tensile modulus of 5,500 MPa against 2,300 MPa for the unfilled Novodur P2M-AT (ISO 527), and a notched Charpy impact strength of 6 against 22 kJ/m² (ISO 179/1eA, 23 °C).
Static-dissipative ABS is marked by surface resistivity. RTP’s static-dissipative ESD A 600 and ESD A 680 grades read 10⁵ to 9.9 × 10¹¹ ohm/sq by ASTM D 257.
Extrusion Grades vs Injection Grades
Extrusion grades of ABS have much lower melt flow than injection grades: sheet and profile need melt strength to hold their shape out of the die, while molding needs flow to fill thin walls. On Versalis’s SINKRAL data sheets, the three extrusion grades run at 8 cm³/10 min or less at 220 °C/10 kg, against 26 cm³/10 min for the injection grade SINKRAL L 322.
Extrusion sheet grades are also sold on low gel content and surface finish.
Compare extrusion and injection grades only on the same quantity and condition. Producer sheets print melt volume rate in cm³/10 min at 220 °C/10 kg, which is a different number from a melt mass-flow rate in g/10 min, and some vendor pages quote ABS at 200 °C/5 kg, a figure that cannot sit in the same column.
ABS Blends and Alloys
ABS is sold blended with polycarbonate, nylon and acrylic, and these blends often sit in a producer’s ABS range although they behave as separate materials:
- PC/ABS and ABS/PC: polycarbonate adds heat and impact resistance.
- ABS/PA: a blend with nylon 6 for chemical resistance and flow, sold for example as INEOS’s Terblend N, including glass-filled versions.
- ABS/PMMA: a blend with acrylic for surface hardness and gloss.
Blend melt flow is often measured at a different condition from ABS, such as 260 °C/5 kg, so check the condition before setting a blend’s figure beside an ABS grade.
ASA, ACS and MBS, which some vendor pages count as modified ABS, are separate materials.