Quantification of the linear viscoelastic behavior of multilayer polymer interlayers for laminated glass

Abstract

In order to meet the qualifications of an acoustic interlayer to EN 12758 (2019), interlayers must have a high damping capacity. For PVB interlayers this is typically achieved by using an increased amount of plasticizer. Since this softens the interlayer and decreases the process ability of the interlayer, trilayer acoustic interlayers comprising relatively stiff skins and a soft core are often used. This paper deals with the characterization of the temperature-dependent linear viscoelastic material behavior of multilayer polymer interlayers using a trilayer acoustic PVB as an example. For this purpose, both the multilayer as a structure and the individual layers were investigated by means of dynamic mechanical thermal analysis. 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 generalized Maxwell models of the individual layers. In addition, a simplified rule-of-mixtures-based 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.