IMPROVING THE PERFORMANCE OF HOT MELT PSAs USING EXTRUSION OR CROSSLINKING TECHNOLOGIES

摘要

The traditional deficiencies of hot melt pressure sensitive adhesives (PSA) are due to the use of relatively low molecular weight polymers, resulting in limited heat and plasticizer resistance. Two methods of overcoming this deficiency are the development of high molecular weight, extrudable PSAs, and post-crosslinking the hot melt after application. Higher molecular weight raw materials can be used to produce high viscosity PSAs with improved performance. These PSAs are processed using extrusion. This adhesive technology provides fast slot die processing speeds, very high cohesive strength, and relatively high heat resistance. Some grades offer improved plasticizer resistance over conventional hot melt PSA. The materials are now available in a convenient pellet form. Crosslinkable hot melt PSAs that are designed to be crosslinked by UV light or electron beam, are also now available. These products offer high processing speeds, relatively low application viscosity, high resistance to plasticizers and solvents, aggressive tack, and very high heat resistance. Performance data compared with alternative adhesive technologies will be provided along with performance on a variety of release liners.