Noise Reduction by Polyvinyl Butyral Interlayers
Polyvinyl Butyral (PVB) is a thermoplastic polymer obtained by the condensation reaction of polyvinyl alcohol and butyraldehyde. It is typically used as an interlayer between two or more layers of glass, often found in the windshield of a vehicle.
The glass and the PVB are sealed by a series of pressure rollers and then heated. This combination of pressure and heat chemically and mechanically bonds the PVB to the glass. This interlayer offers strong elasticity, high impact resistance, penetration resistance, and optimal adhesion properties.
Laminating glass with PVB is one of the most effective ways to reduce unwanted noise. The interlayer dampens vibrations in the windshield, acting an as energy absorber and also reverts the sound back toward the source from which it came. This ultimately reduces traffic, road and wind noises while driving, improving the overall acoustic quality of the passenger’s ride. PVB is typically found on the windshield, but is now commonly offered as an option for side and rear windows as well.
PVB systems target the 1000-3000 Hz range, also known as the “noise transparency” range, which allow for some of the most distracting sounds to penetrate through the glass. By eliminating about 10 decibels within the “transparency” range, it can result in a 50% reduction of recognizable sounds.
Not only do PVB interlayers control sound, but they are also a safety feature among many modern automobiles. The shards and shattered glass caused by a traumatic accident will remain stuck together within the film, retaining the safety of the laminated glass.
Another notable feature of PVB systems are light transmittance properties. PVB interlayer systems can absorb 99% of ultraviolet rays, protecting people, plastics, and upholsteries from its damaging effects. Infrared rays are also absorbed, acting as an insulator and/or a cooling agent within the vehicle.