Laminated glass is produced by bonding layers of glass together under pressure and heat, with a resin called PVB (polyvinyl butyral). This technique is usedto create single sheets of glass with multiple layers. The PVB keeps the glass from breaking apart easily and provides high sound insulation. Laminated glass will flex before shattering. Laminated glass is strong but not as strong as tempered glass. Also, laminated glass blocks nearly 99 percent of ultraviolet light transmission.
Tempered glass is commonly used in frameless glass doors used in commercial settings. Passenger windows in vehicles are usually made of tempered glass. The windshields in automobiles are typically made of laminated glass, as is the glass commonly used in skylights. Laminated glass is often used in applications where there is a severe risk of high winds.
Tempered glass is also sometimes called toughened glass. It is very strong and is often used as safety glass. When tempered glass is broken, it will usually break into very small pieces instead of into big shards. This makes it less likely to cut a person. Tempered glass is known to be several times stronger than laminated glass. Tempered glass is created using chemical and thermal treatments. The treatments give it more balanced internal stress capabilities.
Laminated glass is generally more expensive then tempered glass. Until recently, laminated glazings used to cost three to four times as much as tempered glass. It is mandatory for car manufacturers to use laminated glass in windshields. More companies are using laminated glass in side and rear windows.
The science behind laminated glass and tempered glass can be combined to make laminated glass that is also tempered. When manufacturing this type of glass, the thickness of PVB used has to be just right or some level of bubbling can occur at the edges. This is a difficult process but if successful, laminated tempered glass can have many useful applications. Many car manufacturers are using this technology in their windows now. However, most car companies still choose to use one method over the other.