Rheological Behavior and Adhesion Properties of EVA Based Hot Melt Adhesives: Use of Computation Tools, 1991 Hot Melt Symposium Proceedings

Hot Melt Adhesives for applications such as packaging or book-binding are complex mixtures of polymers, resins and waxes, The Melt Flow Index (MFI) is the basis for choosing the polymer, as it reflects the processing melt viscosity and gives cohesion to the material. A compatible resin is supposed to give better adhesion and determines the lowest temperature of use. “Oils” are also used to plastify the mixture. At last, crystalline waxes allow a fine tuning of the

processability of the material, where the crystallinity and melting point are key factors.

In this paper, a general relationship is established between the physical parameters of a formulation (Tg, melt viscosity and viscoelastic properties) and its composition. The given computational tools may help choosing the right polymer and components ratio to fullfill the processing and mechanical requirements for a given application. This has been applied to the case of HMA based on Vinyl Acetate and Alkyl Acrylate Ethylene copolymers. The effects of polymer molecular weight, wax content and resin content on the processing and mechanical properties are examplified using the basic concepts given in the paper.