New High Performance Tie-Layer Adhesives Selected for Multilayer Pipe Applications

Keywords : pipe, multi-layer pipe, tie-layer, adhesive, adhesion This paper describes the use of tie-layer adhesives in multi-layer pipe (MLP) and barrier pipe applications. Tie-layers are used to provide strong bonding between the polyolefin layer and the metal in MLP applications, and between the polyolefin and the barrier layer such as ethylene vinyl alcohol (EVOH) in barrier pipe applications. The newly developed high-performance tie-layer product under study demonstrates strong adhesion to polar and non-polar substrates under varying temperatures. Detailed studies show a good correlation between pipe adhesion performance and interactions on a microscale and molecular level. Results show that the use of a high-performance tie-layer (HP-tie) together with optimized processing and substrates can reduce or eliminate blisters and maintain high adhesion after thermal cycling. This paper also describes the effect of substrates on the performance of the pipe. Additionally, the effect of the extrusion process and its relationship to material and pipe performance is discussed.