Laminated glass is a combination of two or more glass sheets with one or more interlayers of plastic (PVB) polyvinyl butyrate (which can be uncolored and transparent or colored, xerigrafato, and so on) or resin. The first provides good adhesion to glass and a high level of lengthening before breaking.In case of breakage, the interlayer holds the fragments together and continues to provide resistance to the passage of persons or objects.