Commonwealth Scientific and Industrial Research Organisation

Huntsman Chemical Company Australia Limited

Chemplex Australia Limited

Peter J Collins

Yoshikazu Yazaki

Michael J Delaney

Adhesive composition

A method for producing a relatively low viscosity tannin extract from bark and/or wood and suitable for use in formaldehyde-condensation adhesives comprises providing tannin extract obtained from bark and/or wood, separating from the tannin extract the high molecular weight material, subjecting the high molecular weight material to treatment with one or more sulphite compounds to reduce the molecular weight and recombining the sulphited material with the tannin extract. The tannin extract may be recovered by subjecting bark and/or wood to a first stage hot aqueous tannin extraction process, thereby obtaining a first stage tannin extract, subjecting the extracted bark and/or wood to a second stage hot aqueous extraction process at a higher pH than the first stage, thereby obtaining a second stage tannin extract, and optionally recombining the first and second stage tannin extracts.

Tannin extraction and processing

A wood adhesive composition including an effective amount of a phenol-formaldehyde resin; and a modifying agent which agent renders the composition capable of bonding to a hard wood.

Growing community of inventors

Melbourne, Australia

Peter J Collins