Biobased epoxy resins for computer components and printed wiring boards

Lignin, a by-product of paper manufacturing, has been used to develop a new series of resins for various computer components, particularly printed wiring boards (PWB). PWBs are commonly fabricated from epoxy/fiberglass laminates onto which electrical components are mounted. Replacement of the current petroleum derived phenolic epoxy resins with bio-based materials would reduce the environmental concerns with the fabrication, assembly, and disposal of PWBs. Resins used in PWBs must have a high glass transition temperature, low moisture absorption, high thermal stability, flame retardancy and good dielectric properties. Lignin is the only common phenolic-based biopolymer, thus it is naturally hydrophobic and has good thermal stability. Resin formulations which are lignin/epoxy copolymers (containing at least 50% lignin) exhibit acceptable physical and electrical properties for a wide range of applications, including PWBs. Laminates formed from lignin based resins can be processed in a similar fashion to current laminates, minimizing the financial considerations of converting to this resin system.