Polycarbonate Roll Stock

Translucent white polycarbonate passes light while hiding whatever is behind it, which is what a backlit sign face or a light diffuser needs. It is used for illuminated signage and light boxes, luminaire diffusers, LED panels where hot spots have to be evened out, and backlit displays. The white is a volumetric diffuser rather than a surface texture, so it scatters light through the thickness and gives an even glow instead of a visible lamp image.

The industry white used for this is a long-standing cross-manufacturer colour convention, and the light transmission that goes with it is 27% measured at 0.118 inch - but transmission is strongly thickness-dependent, so take that as the figure for that gauge rather than a property of the colour. A lighter industry white at 50% at the same gauge exists if 27% is too dense for your lamp spacing. Tell us the look you need and we will match the opacity rather than guess from a colour code.

Other published properties: notched Izod 16 ft-lb/in, heat deflection 270F at 264 psi and 280F at 66 psi, specific gravity 1.20, and UL 94 V-2 at 0.093 inch rising to V-0 at 0.236 inch. Instrumented impact is 47 ft-lb by ASTM D3763 at 0.125 inch, far above acrylic or glass, which is the real reason to use it in a ceiling or a sign face that somebody might hit.

Chemical compatibility and cleaning, which is where most polycarbonate failures start. Clean it with mild diluted dish soap and a soft microfibre cloth, or an ammonia-free glass cleaner. Do NOT use ammoniated glass cleaner - the common blue kind - because ammonia attacks polycarbonate, and the resin maker's own testing shows 0.1% ammonia is enough to do damage in the presence of water. Also avoid abrasive or high-alkaline cleaners, scrapers and squeegees, dry rubbing, and solvent in direct sun. Isopropyl alcohol diluted 50/50 with water handles oil and tar. Acetone, MEK, methylene chloride, chloroform, toluene, xylene and aromatic fuels all attack it, and so do amines and the plasticisers that migrate out of flexible PVC - which is why PVC gasket, tape and cable tie contact is a real failure mode. The important subtlety is that chemical resistance is not a fixed property: stress cracking only develops where the part is in tension, so a cold-bent, over-torqued or tightly framed part will fail with chemicals a compatibility chart calls safe.