Methods for preparing a lignin dispersion and a resin from the lignin dispersion

Abstract

The present invention relates to an improved process for preparing an aqueous dispersion of lignin and the use of said suspension in the preparation of a resin.

1 . A method for preparing a lignin dispersion comprising the steps of
 a) providing an aqueous medium having a pH of 1 to 7;   b) adding lignin to the aqueous medium;   c) mixing until a dispersion of lignin in the aqueous medium has been obtained.   
     
     
         2 . A method for preparing a resin comprising the steps of
 a) providing an aqueous medium having a pH of 1 to 7;   b) adding lignin to the aqueous medium;   c) mixing until a dispersion of lignin in the aqueous medium has been obtained;   d) adding alkali, phenol and/or formaldehyde to the aqueous medium and   e) maintaining the mixture at a temperature of from 30° C. to 95° C. for at least 30 minutes.   
     
     
         3 . A method according to  claim 1 , wherein steps a), b) and c) are carried out without actively heating the aqueous medium. 
     
     
         4 . A method according to  claim 1 , wherein the amount of lignin in the dispersion in step c) is 5-60 wt %. 
     
     
         5 . A method according to  claim 4 , wherein the amount of lignin in the dispersion in step c) is 35-60 wt %. 
     
     
         6 . A method according to  claim 1 , wherein the pH of the aqueous medium in step a) is pH 2 to 5. 
     
     
         7 . A dispersion obtainable by the method of  claim 1 . 
     
     
         8 . A resin obtainable by the method of  claim 2 . 
     
     
         9 . Laminate, engineered wood product or insulation product manufactured using a resin according to  claim 8 . 
     
     
         10 . A method according to  claim 2 , wherein steps a), b) and c) are carried out without actively heating the aqueous medium. 
     
     
         11 . A method according to  claim 2 , wherein the amount of lignin in the dispersion in step c) is 5-60 wt %. 
     
     
         12 . A method according to  claim 2 , wherein the pH of the aqueous medium in step a) is pH 2 to 5.