Non-Formaldehyde, Bio-Based Adhesives for Use in Wood-Based Panel Manufacturing Industry—A Review

Abstract

There is a strong need to develop and implement appropriate alternatives to replace formaldehyde-based adhesive systems, such as phenol–formaldehyde, in the industry of wood-based panels (WBPs). This is due to the toxicity and volatility of formaldehyde and restrictions on its use associated with some formaldehyde-based adhesives. Additionally, the current pressure to reduce the dependence on polymeric materials, including adhesives, from petrochemical-based sources has led to increased interest in bio-based adhesives, which, in some cases, already provide acceptable properties to the end-product. Among the potential raw materials for good-quality, renewable-based adhesive formulations, this paper highlights tannins, lignin, and protein sources. However, regarding renewable sources, specific features must be considered, such as their lower reactivity than certain petrochemical-based sources and, therefore, higher production costs, resource availability issues, and the need for toxicological investigations on alternative systems, to compare them to conventional systems. As a result, further research is highly encouraged to develop viable formaldehyde-free adhesive systems based on renewable sources, either at the technical or economical level. Moreover, herein, we also showcase the present market of WBPs, highlighting the obstacles that the alternative and new bio-based adhesives must overcome.

Formaldehyde-Free Resins for the Wood-Based Panel Industry: Alternatives to Formaldehyde and Novel Hardeners

“…Thermosetting resins are used as binders. Amino resins (urea–formaldehyde and melamine–formaldehyde), phenol–formaldehyde, isocyanate-based, and epoxy resins are the most common adhesives in the wood industry [ 2 , 3 ]. Urea– (UF), melamine– (MF) or melamine–urea– (MUF) formaldehyde resins are economically advantageous, and their synthesis and processing pose no technological problems, although the emission of formaldehyde is an inherent feature [ 4 ].…”

Improving Bond Performance and Reducing Cross-Linker Dosage of Soy Protein Adhesive via Hyper-Branched and Organic–Inorganic Hybrid Structures

“…The development of biomass adhesives to replace carcinogenic formaldehyde adhesives is a significant advancement [ 1 , 2 , 3 ]. Vegetable protein adhesives, especially soy protein-based adhesives (SPIAs) have attracted significant attention from the scientific community because of their richness, degradability, and lack of toxicity as harmless substitutes for formaldehyde-based adhesives [ 4 , 5 , 6 ]. However, the poor water resistance and inadequate mechanical properties of SPIAs limit the practical application in wood panel fabrication industry [ 7 , 8 , 9 ].…”

Preparation and characterization of wet adhesives based on (poly (vinyl butyral-co-vinyl alcohol-co-vinyl acetate)/castor oil/styrene butadiene rubber) using gamma irradiation for trapping of reptiles and rodents

“…The capacity of global market of adhesives absorbed more than 14.7 million tons in 2019, with the Asia Pacific region consumed for nearly 38% of the global share, then North America and Western Europe [1].The construction sector consumed more than 26% of the global need in 2019 [2]. Various applications of adhesives need adhesion to take place and continue in wet and underwater media.…”