PVB film is generally stored in refrigerated condition between 2 to 10 ℃. Below 2 ℃, dew may form on the surface if it is exposed in an ambient above 30 % Relative humidity. As advised, 30 % Relative humidity is in relation with the moisture content of most commercial PVB films, as delivered. And if storage temperature is above 10 ℃, refrigerated PVB rolls start showing blocking after some storage time (Blocking means tendency not to be able to unwind without excessive forces).

PVB does not have a shelf life, so theoretically there is no chemical or physical change of the material over time. But a “best use before” time is recommended, purely related to potential roll blocking.

Another way to avoid blocked rolls is to interleave the PVB rolls with embossed Polyethylene film. This also allows to transport and store without needing cooling capacity. It’s an alternative choice when you don’t have refrigerated warehouse. But we still advise to have the roll (in the original moisture proof bag, 24 hours before using) stored at ambient temperature of 20° C. When stored at high ambient temperatures, there is a risk of surface pattern collapse, due to rheology/stiffness’ changes in the PVB.