Ultraviolet light (UV) or electron beam (EB) curing laminating adhesives are creating significant interest for flexible packaging. Acrylate / methacrylate monomers and oligomers as well as photoinitiators are essential components of UV adhesives. Similar monomers and oligomers are used in EB adhesives, but they do not require photoinitiators. Aliphatic urethane acrylates are commonly used in laminations since they have good adhesion to most films and are non-yellowing. These adhesives are also characterized by a very low application viscosity, on the order of 350-450 cps.
RESULTING PROPERTIES
The above table shows a starting formulation for a general purpose UV/EB cured laminating adhesive. Upon curing, these adhesives offer a non-tacky film that provides excellent adhesive strength to a number of different substrates. However, when a specific application requires laminating opaque substrates, EB-curing adhesives may be necessary, since EB cure is not negatively affected by an opaque substrate.
