Polyurethane hot melt adhesive and preparation method thereof

The invention discloses a polyurethane hot melt adhesive and a preparation method thereof, and the polyurethane hot melt adhesive comprises the following components in terms of total 100 parts by mass: 10-25 parts of polyether polyol; 5 to 15 parts of isocyanate; 30 to 55 parts of a tackifying resin; 10 to 30 parts of a thermoplastic resin; 0.05 to 0.5 part of an antioxidant; 0.05 to 0.3 part of a defoaming agent; 0.01 to 0.1 part of a stabilizing agent; and 0.01 to 0.3 part of a catalyst. The raw material components of the polyurethane hot melt adhesive do not contain crystalline polyester polyol, so that the volume shrinkage of the polyurethane hot melt adhesive caused by crystallization can be avoided, the adhesion improvement of a base material is facilitated, and the final adhesion stress is improved; the high-proportion tackifying resin is adopted in the raw material components, so that the viscosity of the polyurethane hot melt adhesive in a hot melt state is effectively reduced, meanwhile, good operat