The adhesion from PVB to glass is ensured through hydrogen bonding between hydroxyl groups from PVB and silanol groups from glass.
Alkaline and Earth Alkaline metal ions (on the glass surface) interact with the silanol groups. Rendering them unavailable for bonding with hydroxyl groups from the PVB. It gives us a way to control the adhesion of the PVB to the glass. Through the tin bath of the float process, the presence of tin-ions can observably reduce the adhesion of PVB to the glass.
In addition, PVB has a large number of Hydroxyl-groups (from PVA), providing it a high affinity to water molecules, and making PVB hygroscopic. Also, glass has a large amount of silanol groups, creating the same surface phenomenon of hygroscopy. When the glass gets wet, water competes for bonding sites on the glass surface and as a consequence reducing the potential adhesive bond.
So if you want a better adhesion, you need to be careful about the ambient moisture.
























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