1. Chemistry and production of PVB interlayers for laminated glass

Until 1935, the only interlayer used was cellulose nitrate (known as "Pyralin"). The first PVB patents were filed by the Union Carbide/Shawinigan Corporation chemical company in 1935. This new thermoplastic polymer was an immediate success, replacing cellulose nitrate (then known as "Pyralin") in laminated automotive safety glass. Since then, the four main PVB manufacturers (PVB Butacite ^® by DuPont (1937) / PVB Saflex ^® by Monsanto (1938) / PVB Trosifol ^® by HT Troplast (1953) and PVB S'LEC™ by Sekisui (1958)) have developed their range of PVBs to suit different types of processing (degassing by calendering or vacuum, processes with or without autoclave) and to the growth and productivity requirements of the automotive (from the 1960s), building (from...