UV Curable Laminating Adhesives for Transparent and Nontransparant Materials

Non-transparent materials can not be laminated by means of radical photo cunng due to the fact that this system is based on a non-living polymerization. The dark cure of cationic UV systems however allows for an initiation of the polymerization and continuation of the reaction after radiation. Formulations can be designed to control this post cure and consequently the "open" time using cure retardants. These products are selected on different criteria: functionality, molecular weight and their influence on the reactivity, adhesion and epoxy/hydroxyl ratio (EHR) of the final formulation. It is demonstrated that epoxy-functional acrylics improve adhesion and contribute to the strength of the laminate. It is also demonstrated that the cure-laminate principle can be used on a variety of flexible and non-flexible substrates.