METHODS FOR PREPARING A LIGNIN DISPERSION AND A RESIN FROM THE LIGNIN DISPERSION
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.