Water-based epoxidized lignin and process for its production and its use as phenol-formaldehyde replacement in adhesives and cross-linkers

Abstract

The invention is the synthesis and use of epoxidized lignin (EL) preferably with but also without colloidal lignin nanoparticles (CLP, plural CLPs). The invention is divided in two parts, synthesis and utilization. The synthesis of the invention is performed in the following general steps: Preparation of an aqueous solution of lignin and a base. Combining the lignin solution with epichlorohydrin at 1-90° C., where the amount of epichlorohydrin should be within 1-20 ml per gram of lignin. Allowing the epoxidation reaction to take place between 1 minutes to 5 hours, while stirring the mixture. Removal of excess epichlorohydrin from epoxidized lignin solution by e.g. solvent extraction. EL functions as a cross-linker and may be used e.g. to prepare adhesives, surface coatings, and composite materials. EL may also be used as foaming agent in water-based solutions.

Dependencies are inferred from the claim text.