Condensed tannin-resorcinol adducts and their use in wood-laminating adhesives: An exploratory study

Abstract

The reaction of a tannin extract (containing about 30% carbohydrate) from loblolly pine (Pinus taeda L.) bark (two parts) and resorcinol (one part) at 120°C for 24 h with acetic acid catalyst gave a product containing predominantly oligomeric procyanidin-4-resorcinol adducts (39%), unreacted resorcinol (22%), carbohydrate (20%). the resorcinol adduct 2R,3R,4S-4-(2,4-dihydroxyphenyl)-flavan-3,3',4',5,7-pentaol (8%)its 2,3-trans isomer (4%), and catechin and epicatechin (7%). The above mixture was used as a resorcinol replacement in a conventional phenolresorcinol-formaldehyde laminating adhesive as used in the manufacture of laminated wood beams. Preliminary gluing results suggest that, with some modification of adhesive formulation and resin synthesis conditions, room-temperature curing adhesives for wood-laminating purposes could be produced successfully using such condensed tannin-resorcinol adducts to replace more than 60% of the resorcinol requirement.

Citation

Hemingway, Richard W.; Kreibich, R.E. 1984. Condensed tannin-resorcinol adducts and their use in wood-laminating adhesives: An exploratory study. Journal of Applied Polymer Science: Applied Polymer Symposium 40:79-90