Eco-friendly adhesives for wood panels: advances in lignin, tannin, protein, and rubber-based solutions
Aakash Kumar, Pranit B. Patil, Dipak V. Pinjari
Abstract
Wood adhesives have been pivotal in enhancing wood utilization for panel production over the past five decades. The increasing global demand for wood-based panels is expected to push the market to $21.8 billion by 2028. Traditionally, adhesives like urea-formaldehyde (UF), phenol-formaldehyde (PF), melamine-formaldehyde (MF), phenol-resorcinol-formaldehyde (PRF), and resorcinol-formaldehyde (RF) resins have dominated due to their strong bonding properties. However, their toxicity and fossil fuel origins have driven research into eco-friendly alternatives. This review explores the potential of ‘green’ adhesives for wood panels, focusing on lignin, tannin, protein, natural rubber, emulsion polymer isocyanate (EPI), 1 C PUR polyurethane, PMDI, carboxylic acid, and vegetable oil-based options. We examine the physical and mechanical properties of these bio-based adhesives and highlight recent advancements in developing sustainable, high-performance alternatives to conventional resins. Uniquely, this review synthesizes comparative performance data, identifies key formulation challenges, and outlines critical innovation trends that could accelerate the commercial adoption of bio-based adhesives in wood panel manufacturing.