tanninbased

Tannin-based refers to materials and products derived from tannins, a class of polyphenolic compounds abundant in many plants. Tannins are divided into hydrolyzable tannins (gallotannins, ellagitannins) and condensed tannins (proanthocyanidins). Common natural sources include gall nuts, quebracho, mimosa, chestnut wood, and bark extracts. Tannins are valued for their ability to bind proteins and metals, form stable complexes, and crosslink under certain conditions.

Tannin-based materials are used in several sectors. In leather tanning, tannins convert animal hides into durable leather. In wood products, tannin-based resins serve as bio-based binders; they can partially substitute phenol in phenol-formaldehyde resins, enabling formaldehyde-reduced or formaldehyde-free adhesives for plywood, particleboard, and other composites. Tannins also appear in coatings and finishes, where they may act as natural precursors for UV-absorbing or antioxidant functionalities. In wood protection and preservation, tannins contribute to natural decay resistance. In environmental applications, tannins are explored as natural coagulants and adsorbents for dye and metal removal from water.

Advantages include renewability, lower fossil-fuel dependence, and potential for lower emissions. Challenges include variability in tannin quality, color and odor, processing requirements, and sometimes inferior performance relative to synthetic resins unless modified or blended. Ongoing research focuses on improved processing methods, formaldehyde-free formulations, and expanding uses in sustainable materials and composites.