Preparation method of water-soluble blocked isocyanate crosslinking agent

The invention discloses a preparation method of a water-soluble blocked isocyanate crosslinking agent. A plurality of existing blocked isocyanates are not suitable for a fabric coating, and has poor binding strength between a coating glue and the fabric. The preparation method provided by the invention comprises the steps of: first grafting hydrophilic groups into an isocyanate structure; blocking excessive isocyanate groups with a sealant; and finally emulsifying, dispersing and distilling to removal a solvent, so as to obtain the water-soluble blocked isocyanate crosslinking agent. The water-soluble blocked isocyanate crosslinking agent provided by the invention can be applied to a fabric coating process to significantly improve the peeling strength of the coating, and improve hydrostatic pressure, wet rubbing fastness, tensile strength and washing fastness of the coating by different degrees.