Multifunctional polymer additive and preparation method thereof

The invention provides a multifunctional polymer additive. The multifunctional polymer additive is prepared from the following components in parts by mass: 40 to 55 parts of modified acrylic resin, 8 to 15 parts of modified phenolic resin, 0.3 to 1 part of cellulose ether, 0.5 to 2 parts of wood fiber, 1.0 to 2.0 parts of auxiliaries and water, wherein the modified acrylic resin is obtained by reacting epoxy resin, lignin and an acrylic monomer; the modified phenolic resin is lignin modified phenolic resin. The modified acrylic resin and phenolic resin have groups similar to those of cellulose ether and wood fibers, so that the compatibility is good, and meanwhile, the modified acrylic resin and phenolic resin contain various functional groups such as double bonds, carbonyl, phenolic hydroxyl groups and alcoholic hydroxyl groups, so that chemical crosslinking can be carried out among the components, or intermolecular acting force is formed, and a synergistic effect is generated; the adhesive property and the