Aqueous wax emulsions and dispersions and uses thereof
An aqueous wax emulsion or dispersion comprising, wax, water and an emulsifier wherein the emulsifier comprises purified kraft lignin and a water-soluble base. A process for preparing said aqueous wax dispersions and their use.
1 . A method of manufacturing a composite wood panel comprising the steps of (i) resinating lignocellulosic material in the presence of an adhesive resin and an aqueous wax emulsion or dispersion, (ii) forming the resinated lignocellulosic material containing adhesive and aqueous wax dispersion, and (iii) consolidating the formed lignocellulosic material using pressure and temperature;
wherein the aqueous wax emulsion or dispersion comprises:
wax;
water; and
an emulsifier, wherein the emulsifier comprises lignin and a water-soluble base; and wherein
the water-soluble base is present in an amount sufficient to dissolve the lignin.
2 . The method of claim 1 , wherein the lignin is a Kraft lignin that can be solubilized in water.
3 . The method of claim 1 , wherein the lignin is purified Kraft lignin wherein the purification is by a LignoForce or LignoBoost process.
4 . The method of claim 1 , wherein the water-soluble base is selected from the group consisting of mono-functional amines, multi-functional amines, alkali metal salts, alkaline earth metal salts, and combinations thereof.
5 . The method of claim 1 , wherein the amount of base is determined by the acid dissociation constant (pKa) of the base.
6 . The method of claim 1 , wherein the base has a pKa≥9.4.
7 . The method of claim 6 , wherein the base is potassium hydroxide, sodium hydroxide, or monoethanolamine.
8 . The method of claim 7 , wherein a minimum equivalent base mass ratio is about 0.07.
9 . The method of claim 1 , wherein the base has a pKa<9.4.
10 . The method of claim 9 , wherein the base is diethanolamine or triethanolamine.
11 . The method of claim 10 , wherein a minimum equivalent base mass ratio is in the range of 0.17 to 0.095.
12 . The method of claim 1 , wherein the base is a volatile base.
13 . The method of claim 1 , wherein the wax is paraffin slack wax, refined paraffin wax, Fisher Tropsch wax, polyethylene wax, synthetic wax, natural wax, or mixtures thereof.
14 . The method of claim 13 , wherein the polyethylene wax is oxidized polyethylene wax or maleated polyethylene wax.
15 . The method of claim 13 , wherein the natural wax is a vegetable wax or animal fat.
16 . The method of claim 1 , wherein an equivalent solubilized lignin mass ratio is greater than 0.008 and less than or equal to 0.25.
17 . The method of claim 16 , wherein the equivalent solubilized lignin mass ratio is greater than 0.01 and less than or equal to 0.1.
18 . The method of claim 17 , wherein the equivalent solubilized lignin mass ratio is greater than 0.02 and less than or equal to 0.04.
19 . The method of claim 1 , wherein the wax comprises between 20 wt % to 60 wt % of the total solids of the aqueous wax dispersion.
20 . The method of claim 1 , wherein an equivalent solubilized lignin mass ratio is greater than 0.002 and less than or equal to 0.25.