Polyurethane latex as well as preparation method and application thereof

The invention discloses polyurethane latex as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out primary polymerization reaction on polyester polyol and toluene diisocynate; adding a chain extender and a solvent, and carrying out chain extension reaction; the preparation method comprises the following steps: uniformly dispersing polyisocyanate with the functionality of more than 3, mixing with an emulsion, emulsifying and cross-linking, and removing acetone to obtain the polyurethane latex. According to the preparation method of the polyurethane latex provided by the invention, ternary isocyanate is added before emulsification, in the subsequent emulsification process, a prepolymer can be crosslinked with triethylene tetramine to form a net structure while emulsification is carried out, and the crosslinking degree is controlled by an emulsification reaction, so that the cohesion of polyurethane can be obviously improved, and the flexibility