Mechanical Testing of Liquid Cold-Poured Interlayer Adhesives for Laminated Safety Glass

Abstract

Research and development in the field of structural glass engineering is constantly exploring new materials and innovations to improve the performance and versatility of laminated safety glass (LSG). Liquid cold-poured interlayer adhesives (LCPI) are emerging as an alternative to film-based interlayers, such as PVB, EVA, and Ionomers, and are gaining increasing attention in research. These products are cured at room temperature without the need for additional pressure. Their mechanical and physical properties can be adjusted depending on the intended application. Therefore, they can range from highly flexible, allowing for the integration of elements such as photovoltaics or screens, to very stiff, in order to enhance the load-bearing behavior of LSG. In this paper, three LCPIs covering this range are investigated with respect to their mechanical properties. Each adhesive is tested under different stress states, including bulk material tests (uniaxial and biaxial tension tests) as well as shear tests on small-scale laminated glass specimens. Since all investigated materials exhibit viscoelastic behavior, strain-rate- and time-dependent effects are studied in the uniaxial stress state using different strain rates, cyclic loading, and relaxation tests. To evaluate the suitability of the adhesives for laminated safety glass, pendulum tests on large-scale laminated glass specimens are conducted. All three adhesives show promising mechanical performance and post-breakage behavior within the Pendulum tests, indicating their potential for use in laminated safety glass.