Preparation of adhesive for bamboo plywood using the concentrated papermaking black liquor or lignin

Current status of adhesive for bamboo plywood and the treatment of papermaking black liquor were analyzed synthetically. Adhesive for bamboo plywood prepared using lignin existing in the black liquor as a kind of material replacing part of phenol was proposed, on the basis of the same structural properties of lignin and phenol. There are two technique routes: for the concentrated black liquor, methylation and then applied to preparation of adhesive directly. Both alkali and lignin are utilized without second pollution; for black liquor cannot be used for adhesive preparation, firstly acidulating and precipitating lignin from black liquor, methylation and then applied to preparation of adhesive. The process of adhesive preparation was studied in detail. The technique has applied to the industrial production successfully. All terms of performance of bamboo plywood prepared using black liquor phenolic resin or lignin phenolic resin are better than that of the excellent bamboo plywood of national criteria. Using this technique, the cost depresses up to 30-40% without altering the traditional adhesive producing technique flow, and without adding additional equipments.