ABS grade selection decides whether an injection-molded part fills easily, survives a drop, passes a flame test and keeps its gloss. Every ABS is the same three monomers, but producers shift the rubber content, the acrylonitrile level, the melt flow and the additive package to make grades for very different jobs. Picking by price or by a single datasheet number leads to rejected parts or an over-specified material. As a formulation development partner, SYCHEM TECH supplies the main grade types and the additives that tune them.
Short answer: start from the one requirement the part cannot fail. General-purpose ABS covers gloss and balanced toughness; high-flow grades fill thin walls; high-impact or chemical-resistant grades handle drops and cleaning agents; flame-retardant grades meet UL94 V-0 or 5VA; high-heat grades take Vicat up to about 115 °C; plating grades take chrome; ASA goes outdoors; MABS is transparent. Then compare melt flow, notched impact and Vicat on the TDS.
How ABS works: the basis of ABS grade selection
ABS is a two-phase material. A rigid matrix of styrene-acrylonitrile (SAN) copolymer gives stiffness, hardness and chemical resistance. Dispersed in it are small particles of polybutadiene rubber, grafted with SAN so that they bond to the matrix. When the part is struck, the rubber particles absorb the energy and stop cracks.
Each grade type moves this balance. More rubber raises impact strength but lowers stiffness and melt flow. More acrylonitrile raises chemical and heat resistance but makes the melt stiffer. Particle size and its distribution set the trade-off between gloss and toughness, and decide whether the surface can be etched for plating.
ABS grade selection table: 8 grade types compared
| Grade type | What is different | Typical spec | Typical parts | Example grades |
|---|---|---|---|---|
| General-purpose | Balanced rubber and AN content; high gloss | Vicat about 93–104 °C | Appliance and electronics housings, interior trim, consumer goods | CHIMEI POLYLAC® PA-757 |
| High-flow / thin-wall | Lower viscosity for long, thin flow paths; some impact traded away | MFI about 30–80 | Laptop and TV frames, large thin housings | POLYLAC® PA-756H, PA-737 |
| High-impact / chemical-resistant | More rubber and/or AN; resists cleaners and oils | Higher notched impact | Power tools, chemical-exposed and medical housings | POLYLAC® PA-797, PA-758R |
| Flame-retardant | Halogen or non-halogen FR package | UL94 V-0 at 1.0–2.5 mm, or 5VA | Power outlets, TV frames, printer and battery housings | POLYLAC® PA-765, PA-764B |
| High-heat | Heat-resistant comonomer raises softening point | Vicat about 105–115 °C | Coffee machines, small kitchen appliances | High-heat series from several producers |
| Plating | Rubber phase tuned for etching and chrome plating | Plating adhesion | Grilles, emblems, plumbing fixtures | Plating grades from several producers |
| ASA | Acrylic rubber instead of butadiene | UV and weather resistance | Exterior automotive and building parts | KIBILAC® ASA |
| MABS | MMA added for transparency | Optical clarity | Transparent housings, medical devices | POLYLAC® MABS |
Spec ranges and example grades are from our ABS resin page, which also lists grades from LG Chem, INEOS Styrolution and Chinese producers. They are typical values, not specifications; ask for the TDS of the exact grade.
The trade-offs behind every ABS grade
- Flow vs impact. High-flow grades fill long, thin cavities and shorten cycles, but carry less rubber or a lower molecular weight, so impact strength is lower. If a thin part must also survive drops, look for a high-flow, medium-impact grade rather than the highest-flow grade.
- Impact vs stiffness. More rubber makes the part tougher and less notch-sensitive, but softer. Screw bosses and snap fits need enough stiffness to hold.
- Chemical and heat resistance vs flow. Higher acrylonitrile content or a heat-resistant comonomer resists cleaners, oils and heat better, but needs higher melt temperatures.
- Flame retardancy vs toughness. FR packages lower impact strength and can narrow the processing window; FR grades are balanced for this, so avoid adding FR to a standard grade yourself.
- Gloss vs matte. Fine, narrow rubber particles give high gloss; low-gloss grades or texture suit interior parts where reflections matter.
ABS grade selection by application
Medical and laboratory device housings
Housings for monitors, pumps and diagnostic devices are wiped with alcohol, disinfectants and cleaning agents many times a day. Standard ABS can develop environmental stress cracks around screw bosses and snap fits under that exposure. Chemical-resistant ABS, such as CHIMEI POLYLAC® PA-797 or PA-758R, is the usual starting point; MABS covers transparent covers and windows, and ABS/PC alloys add toughness and heat resistance where needed.
Medical use brings documentation requirements. Biocompatibility and regulatory statements are specific to each grade and come from the producer, so confirm them for the exact grade before you design it in. We can email the available documents with the TDS.
Automotive interiors
Trim, consoles, vents and pillar covers need a consistent surface, low warpage, heat resistance in a closed car and low odor. General-purpose and high-heat grades cover most parts, plating grades go into chrome trim, and ASA takes over on exterior parts exposed to sunlight.
Electronics and household appliances
Thin-wall housings for laptops, TVs and printers use high-flow grades; parts near mains voltage or batteries need FR grades rated V-0 or 5VA at the actual wall thickness; coffee machines and kettles need high-heat grades. Check the UL rating at your wall thickness, not just the grade name.
Additives that fine-tune an ABS grade
- Impact for recycled or filled ABS. Our SY-AR toughening agent, a high-rubber butadiene terpolymer, is mixed with virgin or recycled ABS at 3–10% to restore impact strength.
- Glass-fiber and mineral-filled ABS, PC/ABS. MAH-grafted ABS compatibilizers SY-AC and SY-AD bond ABS to fillers and help PC/ABS blends; SY-AE compatibilizes PA/ABS. See compatibilizer vs toughening agent for which one you need.
- Flow, release and scratch. EBS wax works as an internal lubricant and release agent; a SAN-carrier silicone masterbatch at 0.5–5% improves flow, surface slip and scratch resistance, and anti-squeak grades help PC/ABS interior parts.
- Heat and light. Butadiene is sensitive to oxidation and UV. Add antioxidants for processing and heat ageing, and use ASA or a UV package for outdoor parts.
ABS grade selection checklist
- Environment: service temperature, cleaning agents or chemicals, sunlight, drop or impact risk.
- Part and mold: wall thickness, flow length to thickness ratio, gate positions.
- Rules: UL94 rating at your thickness, automotive odor and VOC limits, medical or food-contact documents.
- Finish: high gloss, texture, painting, plating or laser marking.
- Trial: mold sample plaques or real parts under your own conditions before you approve a grade.
Frequently asked questions
What is the difference between high-impact and high-flow ABS?
High-impact grades carry more rubber and resist drops and notches better, but flow less easily. High-flow grades fill thin walls fast but are less tough. Medium-impact, high-flow grades sit between the two for thin parts that still need some toughness.
How do I compare ABS grades from different producers?
Check the test standard first. ISO notched Izod is reported in kJ/m² and ASTM Izod in J/m, and the two cannot be converted directly. Melt flow can be given in g/10 min or ml/10 min under different loads. Compare grades tested to the same standard, or mold your own plaques.
Which ABS grade is best for medical device housings?
Usually a chemical-resistant grade, because disinfectants cause stress cracking in standard ABS. Use MABS for transparent parts and ABS/PC where more heat or toughness is needed, and confirm the producer’s regulatory documents for the exact grade.
Can I use ABS outdoors?
Standard ABS yellows and loses impact strength in sunlight. Use ASA for unpainted outdoor parts, or paint or UV-stabilize ABS.
Can recycled ABS replace virgin grades?
For many non-cosmetic parts, yes, if the impact loss is corrected. A high-rubber toughening agent such as SY-AR at 3–10% restores much of it; test colour, odor and flame rating separately.
Get an ABS grade recommendation
Need help with ABS grade selection? Tell us the part, wall thickness, service temperature, chemicals it meets and any UL or medical requirements. We will suggest an ABS grade type and grade, email you the TDS and arrange samples. Contact our technical team or write to info@sychemtech.com.
Related products: our ABS resin grades, GPPS and HIPS, PPO/PPE, SY-AR toughening agent and ABS compatibilizers, and the full engineering plastics range. For nylon, see PA6 vs PA66; for styrenic elastomers, see SEBS vs SBS.
