Polycarbonate Film, Polished One Side

This is polycarbonate film rather than sheet: thin gauge, transparent, polished on one face and velvet-textured on the other. The velvet side gives mar resistance and takes ink without pretreatment, which is why the film is used for printed graphic overlays and membrane switch faces, labels and nameplates, floor graphics, in-mould decoration, and diffuser layers over LEDs.

Published properties: light transmission 90% with haze 42% and a yellowness index of 0.9 by ASTM D1003 and D1925 - note that the high haze is the velvet texture doing its job, and it is why transmission stays high while the film still diffuses. Density is 1,200 kg per cubic metre, the glass transition temperature is 307F, Vicat B softening is 323F, and heat deflection measured by TMA at 1.8 MPa is 290F. Gauge tolerance is plus or minus 3% at 0.020 to 0.030 inch, tightening from plus or minus 10% at 0.005 inch.

Film is a different product from sheet in handling as well as thickness. It is supplied with an interleaf or masking that should stay on until fabrication, it will take a set if stored rolled too tightly, and the velvet face is directional - print and bond to the face your process calls for, because the two sides behave differently with ink and adhesive.

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.