Wood adhesives from peanut skin tannin-formaldehyde resins modified with phenols

Peanut skin tannin extract-formaldehyde condensates were modified with resorcinol and cashew nut shell liquid. The copolymer resins formed were used as thermosetting and cold-setting exterior grade wood adhesives for Sapele veneer panels. Results obtained showed that, on addition of paraformaldehyde, the resins modified with resorcinol cured at ambient temperatures while those modified with cashew nut shell liquid cured at higher temperatures. The bonded panels developed strength and durability satisfying the requirements of International Standard Specification for phenolic resin adhesives.