Polycarbonate chemical resistance covers mild detergents and stops well short of solvents. A food plant replaced its machine guard windows with 6 mm polycarbonate, then cleaned them each shift with the same caustic foam used on the line. Within three months every panel had a stress-crack pattern radiating from the fixing holes. The impact performance was irrelevant; the cleaning agent had won.
Polycarbonate chemical resistance is a narrow window compared with acrylic. It handles water, mild detergents, alcohols and dilute acids; it does not handle strong alkali, ketones or chlorinated solvents, and it is particularly vulnerable when the part is under stress.
Polycarbonate chemical resistance: the compatible list
- Safe: water, neutral detergent, diluted isopropyl alcohol, silicone polish
- Short contact only: dilute acids, mild bleach solutions, wiped and rinsed
- Avoid: ammonia, caustic soda, acetone, MEK, aromatic and chlorinated solvents
- Never: abrasive cream cleaners, scouring pads, solvent-based degreasers
Two variables decide whether a chemical that looks acceptable in a chart will actually damage a panel: concentration and dwell time. A 1 percent detergent wiped and rinsed is harmless. The same product at 5 percent, left to dry on the surface overnight, can haze a stressed panel.
The engineering response is to remove stress and choose the cleaner. Annealed, machined parts resist far better than parts cut and clamped with residual stress. Where the cleaning regime cannot change, a hard-coated polycarbonate is worth the premium.
A coupon test before any rollout
Before specifying panels across a plant, take three 100 x 100 mm coupons of the exact grade, clamp one to a stressed condition with a screw at 2 Nm, and expose the set to the real cleaning chemical at the real concentration and dwell time for 30 days. Check for haze, crazing and colour shift.
This costs almost nothing and settles the argument. Sites that skip it usually discover the answer on a full installation, when the panels are already drilled and fitted.
One more interface: chemical resistance and scratch resistance are not the same property. A panel that survives the cleaner may still haze from wiping. The polycarbonate scratch resistance guide covers coating options, and the cleaning and maintenance guide lists the cloth and agent combinations we recommend on site.
If the environment also carries a fire specification, the chemical question has to be answered alongside the flame rating, which the PC UL94 guide explains.
Send us the cleaning chemicals used on your site at oversales@rpplexiglass.com and we will advise on grade and coating.
Frequently Asked Questions
What cleaners are safe on polycarbonate?
Water with a mild neutral detergent, isopropyl alcohol diluted, and most silicone polishes. Avoid ammonia, strong alkali, ketones and aromatic solvents, and never use an abrasive cream cleaner.
Why does polycarbonate crack where it is clamped?
Stress cracking. A clamped or drilled edge is under load, and an alkaline cleaner lowers the surface energy enough for a crack to start. Annealing the part and using a neutral cleaner prevents most cases.
Does hard coat improve chemical resistance?
Yes, a hard coat resists both abrasion and many mild chemicals. It does not make the panel resistant to strong solvents, and coated sheet must still be cleaned with compatible agents.