About UV coating of polycarbonate sheets
- May 23, 2017
- Posted by: ympcsheet, ympcsheet
- Category: Others
Polycarbonate sheets are manufactured under rigid quality control specifications to meet the desired criteria. Quality control begins from the extrusion process through to the final treatment stages where they are coated with various protective layers to prolong their service lifespan.
The polycarbonate sheets UV coating protects these sheets from loss of mechanical integrity. Some of the essential mechanical integrity of polycarbonates includes high impact strength and durability. When a polycarbonate sheet is exposed to UV-B radiation, the photo-degradation transforms the polymers’ chain scission. As the molecular strength decreases, the molecular weight decreases significantly. Furthermore, the presence of certain metal compounds act as a catalyst in this process. This is one of the main reasons why the polycarbonate manufacturers do indicate those cleaning agents which should be used during the cleaning process.
The UV-A is responsible for the yellowing wavelengths. As the ozone layer depletes due to global warming, the amount of UV-A and UV-B increases significantly. Normally, the UV rays do not “penetrate” these sheets. They mainly attack the outer layer of the polycarbonate sheet.
Since the amount of UV radiation varies from one place to the other, PC sheets may have different degrees of polycarbonate sheets UV coating. Therefore, you need to specify the exact region where you’re planning to install these sheets. The nature the thin microscopic layer which is used to coat the PC sheets will determine the warranty period. It is also an important aspect which differentiates various types of PC sheets in the market. The degradation process is determined based on the yellow index (YI) of the sheet. The YI is calculated from the spectrometric data and it indicates the change which exists between the test sample and the clear color (white).
Anyway, If no UV on the polycarbonate sheet, there will no any quality warranty, when you buy polycarbonate sheet, remember check how thickness your supplier will add the UV layers, this is the key factor to affect your sheet quality.