To exhibit good acoustic properties, PVB interlayers must contain a high plasticizer content. Since this makes handling in the lamination process more difficult, multilayers with stiff surfaces and a soft core are often used.
The following paper deals with the characterization of the temperature-dependent linear viscoelastic material behavior of multilayer interlayers. For this purpose, both the multilayer as a package and the individual layers were investigated by means of DMTA. It was shown that the temperature-dependent linear viscoelastic material behavior of the multilayer can be calculated from the material behavior of the individual layers by combining the generalized Maxwell models of the individual layers. In addition, a simplified formula was used to approximate the material behavior of the multilayer from those of the individual layers. The calculation method presented is generally valid and therefore also transferable to materials other than PVB.