Preparation method and application of collagen-based adhesive

The invention provides a production method for synthesizing an aqueous adhesive by using collagen modified by polyurethane and epoxy resin. The method includes: firstly, extracting a collagen hydrolysate from raw materials, such as leftover material of leather manufacturing, bones and the like, which contain the collagen, number-average molecular weight being 10,000 to 30,000; then at 50-80 DEG C,synthesizing an isocyanate-terminated polyurethane prepolymer containing a hydrophilic group and mixing the prepolymer with a certain amount of epoxy resin, and adding a salt-forming agent so as to form salts with carboxylic group; finally, adding deionized water, so that during dispersion and emulsion, the collagen hydrolysate can be subjected to grafting reaction with the polyurethane and epoxyresin, thereby synthesizing the aqueous adhesive based on the collagen modified by polyurethane and epoxy resin. In application, a curing agent and filler are not added, or are added to a certain amount, for adhesion of plywo