Of sulfate - or sodium carbonate - black liquor shown, and a method in order to glue it

摘要

1382964 Phenolic resin adhesive T U E ENKVIST 10 July 1973 [10 July 1972] 32843/73 Heading C3R A process for preparing an aqueous adhesive based on Kraft or soda black liquor from the pulping industry, with a dry matter content greater than 25% by weight, comprises treating the black liquor with formaldehyde and mixing it with a separately prepared phenol-formaldehyde resin in a proportion such that the amount of phenol used in the preparation of the resin is 15-50% by weight of the sum of the organic matter of the black liquor and the phenol used. The black liquor may be heated with formaldehyde and then added to the phenolic resin, or the black liquor and formaldehyde may be added to the phenolic resin and heated in the same vessel. Formalin or paraformaldehyde may then be added to the adhesive reaction mixture, and the pH is then preferably adjusted to a value of 7-11 measured after 1:10 dilution with water. Conventional additives may also be added. In the examples the black liquors used in the preparation of the adhesives are prepared from a kraft digestion of (1) a mixture containing Scotch pine and spruce; (2) birch wood; and (3) a mixture containing birch, pine and spruce; the additives used are powdered coconut shell (VAVANITE, R.T.M.), Quebracho extract, wheat flour, pine-bark flour and chalk. The adhesives of the examples are used to glue birch plywood.