Preparation of Binders from Inexpensive By-products for Use in High-Pressure Phenolic Laminates: Reactive Phenosolvan Pitch-Lignin Derived Products for Use in Impregnating Varnishes and Testing of 6-Ply Hessian-Paper Laminates

SYNOPSIS Equal mixtures of phenosolvan pitch and autohydrolysis bagasse lignin in the presence of either acid or alkaline catalyst and without catalyst were submitted to a thermal treatment stage at 230°C (Phenolation). Each of the phenolated products was mixed with phenol resol varnish (ratio 50: 50) for impregnation into 6-ply hessian Kraft paper laminates. Laminates impregnated with phenol resol and phenolated pitch/lignin with a hexamine hardener addition solely served as references. Laminates impregnated with each mixture produced adequate tensile and flexural strength, while the mixtures containing either the acid or alkaline phenolated product were superior in stiffness to phenol resol and the mixture without catalyst. All mixtures and the phenolated pitch/lignin with hexamine lacked the toughness of the phenol resol system.