PC/ABS is one of the most widely used engineering blends in manufacturing, and one of the most commonly mis-specified. Buyers often arrive with a requirement written as "ABS with better impact" or "PC that flows easier" — which is, roughly, what the blend delivers. But PC/ABS blend properties are not a simple average of the two resins: the alloy behaves differently on heat, flow, impact and processing, and the exact ratio, the compatibiliser package and the grade family change the numbers a buyer is relying on. This guide explains what the blend is, how its properties compare with the parent resins, and what to specify when sourcing.
What PC/ABS Actually Is
PC/ABS is a two-phase alloy of polycarbonate and ABS. The PC phase carries impact resistance and heat performance; the ABS phase — technically the SAN copolymer inside it — improves flow, processability and cost balance. Because the two polymers are immiscible, the blend only works with a compatibiliser, usually a small fraction of PC-grafted SAN or an equivalent reactive copolymer. That compatibiliser is invisible on a data sheet, yet it decides the blend's real toughness: an under-compatibilised alloy can show fine notched impact in the laboratory and still crack on a dropped part. Most commercial grades run somewhere between 60/40 and 30/70 PC to ABS, and the blend is named for whichever phase dominates — a 70/30 grade is usually called PC/ABS, a 30/70 grade ABS/PC, and the two are not interchangeable on property.
How PC/ABS Blend Properties Compare With the Parents
| Property | ABS | PC/ABS | PC |
|---|---|---|---|
| Notched impact | Moderate | Good at low temperature | Very high, but notch-sensitive |
| Heat resistance (HDT) | ~95-110 C | ~110-125 C | ~130-145 C |
| Melt flow | Excellent | Good | Moderate, high viscosity |
| Dimensional stability | Good | Good | Very good |
| UV stability (unmodified) | Fair | Fair to good | Poor |
| Cost position | Low | Mid | High |
The practical reading: PC/ABS sits between the two parents on nearly every axis, which is exactly why it appears in products that would fail in ABS on impact and would be awkward in PC on flow or cost. The figures above are indicative ranges for unfilled grades — the exact values belong to the specific grade, and any supplier quoting a property without naming the grade is quoting marketing.
Processing: What the Blend Asks of the Moulder
PC/ABS processes more like PC than like ABS. It must be dried — two to four hours at 100-110 C is typical — because both phases hydrolyse at melt temperature, and wet material shows up as streaks, brittle parts and molecular weight loss. Melt temperatures commonly run 240-270 C, with mould temperatures of 60-80 C to balance flow against gloss and residual stress. The blend is more sensitive to mould temperature than ABS: too cool, and weld lines and brittleness appear; too hot, and cycle time suffers with little gain. Screw design matters less than drying discipline, which is why an audit of a PC/ABS programme should start at the dryer.
Where PC/ABS Is Used
- Automotive interiors — dashboard substrates, console parts and vent grilles where impact at low temperature matters more than gloss.
- IT and office equipment — laptop chassis, monitor housings and copier panels, the classic application for the blend's flow-toughness balance.
- Appliances — vacuum cleaner housings, power tool shells and control panels with painted or plated finishes.
- Telecom enclosures — housings needing a flammability rating with better flow than FR PC.
Specifying and Sourcing
Start from the duty, not the resin name: the drop height the part must survive, the service temperature, the flammability rating and the wall thickness it is quoted at, the finish required. Flame-retardant PC/ABS grades follow the additive families covered in our guide to flame retardant plastic grades, and the comparison with the parent resins in the ABS vs PC selection guide is a useful companion. Ask suppliers for notched impact at the part's actual wall thickness and temperature, heat deflection temperature under load, and the drying and moulding window — then verify the first shots against those numbers rather than the brochure. Resin suppliers are listed under plastic raw materials, and factory-level screening is available through the supplier directory.
