Advanced acoustic absorption technologies for automotive
Acoustiflex® MDI-based polyurethane technologies from Huntsman are a significant advance in lightweight acoustic absorption. Because Acoustiflex can be used in lower thicknesses than traditional fibrous materials, bulk and weight can be dramatically reduced. There are different technologies in the Acoustiflex range:
 
Acoustiflex VEF and VEF+
These are MDI-based Visco Elastic Foams with vibration damping characteristics for effective sound absorption in automotive applications such as carpet back foaming. VEF and VEF+ are formulated systems, which simplify production.
Acoustiflex VEF+ features a unique ratio between hardness (CLD) and stiffness (E modulus), with one-half the stiffness expected of viscose foam at the same level of hardness. This means that VEF+ better absorbs vibration, lowering noise levels. It also maintains its vibration damping properties, even at higher hardnesses.
 
 
Acoustiflex HR and HR+
Acoustiflex HR is an MDI-based foam providing a range of acoustic solutions to meet different OEM process, density, physical property and acoustic requirements. It is used in dash insulator and under carpet applications, and is available either as a full system or as an isocyanate for self-formulators.
Acoustiflex HR+ is a fully-formulated system, offering processing advantages compared to traditional HR technologies. These include significantly faster demold times, which means increased production efficiency and capacity. In addition, Acoustiflex HR+ works well with water-based release agents, eliminating the need for solvents. Used in dashboard and undercarpet applications, this technology provides enhanced visual appeal and meets most OEM specifications.
 
 
Acoustiflex R
This is a new, rigid, acoustically active PU foam, specifically developed for the automotive roofliner market. It is rigid and sound absorbing, and can be shaped without breaking. It does not release debris following roof airbag deployment, so enhancing passenger safety. Because Acoustiflex R is acoustically active, it absorbs noise without the need for post-treatment (needle punching). It meets OEM roofliner density specifications, and is significantly lighter than traditional materials and meets low emissions specifications.
 
 
Acoustiflex S
A stiff, self-supporting MDI-based foam typically used for the engine compartment as a bonnet liner, as well as for the engine-side dashboard and as a transmission tunnel insulator. It is lighter (up to two-thirds less) than traditional materials, yet stiff enough that it secures easily it to the bonnet, simplifying underhood assembly and increasing production efficiency for OEMs.
 
 
Acoustiflex F
A new MDI-based flexible foam ideal for use in wheel arches and as an acoustic stuffer (including pillar foams), and as a replacement for flexible foam slabs. It provides good sound absorption, meets MVSS 302 fire resistance requirements, and features low emissions.
 
For more detailed information:
Acoustic Absorbers: A third way for the management of sound in automobiles by Chris Skinner, Johan Peters & Jan Vandenbroeck . (PDF, 894 KB)