The windshield (North American English) or windscreen (Commonwealth English) of an aircraft, car, bus, motorbike or tram is the front window, which provides visibility whilst protecting occupants from the elements. Modern windshields are generally made of laminated safety glass, a type of treated glass, which consists of, typically, two curved sheets of glass with a plastic layer laminated between them for safety, and bonded into the window frame.

About PVB

PVB means PolyVinylButyral which was developed  in the early 1930’s and has been produced ever since by a select group of manufacturers worldwide. PVB resin is a non-toxic, non-corrosive product. It has excellent characteristics of transparence, insulation, film-forming properties, impacting resistance and drawing performance.
It has good tensile strength, adhesiveness, elasticity, and is free from inorganic and aliphatic acids. It also owns combination properties of light-proofness, freezing and aging resistance, etc.
PVB resin is not dissolvable in water but is soluble in organic solvents, such as alcohols, esters, ketones, benzene, and in mixed solvents like for example ethyl alcohol and aromatic hydrocarbons.