Clear Laminating Film: Polyvinyl Butyral Plasticised with Tributyl Citrate and Extruded (Nason, Monsanto, US 2,126,028)

The clear layer inside safety glass must stay rubbery from frost to summer heat and stick to glass on its own. Nason softened polyvinyl butyral with tributyl citrate, which stays in the film far better than the usual phthalate. Result: a clear, rubbery, non-tacky film that bonds glass under heat and pressure without glue. Source: Nason, US 2,126,028 (Monsanto, 1938). He used Butvar resin; ours is the polyvinyl butyral we make. Not given: film thickness. Picture drawn by Youblob.