Drying polycarbonate sheet
Polycarbonate sheet readily absorbs moisture from the air. Eventually the water content will reach 0.2% by weight. In most applications this water content is not a problem, however, in applications where you need to process the sheet above a temperature of 250F, this water can vaporize within the sheet during processing and lead to small bubbles forming. As little as 0.05% water can cause these bubbles. Two processes that require the sheet to be heated above 250F are lamination of the Polycarbonate and thermoforming of the Polycarbonate. Both of these processes can have problems with bubbles if the sheet is not dried correctly. This article discusses drying polycarbonate sheet before either lamination or thermoforming.