Enhanced Continuous Lamination Process for Composites
Original Publication Date: 1988-Mar-01
Included in the Prior Art Database: 2005-Feb-14
The construction of multilayered printed circuit boards is typically accomplished by interleaving copper layers and dielectric layers consisting of glass cloth impregnated with an epoxy (prepreg). The impregnation process involves the use of solvents and latent curing agents, such as dicyandiamide (DICY), which has severe solubility problems in impregnation solvents. The improper removal of these solvents during processing causes crystallization of the DICY. This makes the prepreg susceptible to moisture problems due to the hygroscopic nature of DICY. Latent curing agents can be avoided by using a continuous lamination process which uses a photolytic curing mechanism. The process works as described in the following two variations.