Phosphorus-based flame-retardant waterborne polyurethane material and preparation method thereof

The invention belongs to the field of modified waterborne polyurethane materials, and particularly relates to a phosphorus-based flame-retardant waterborne polyurethane material and a preparation method thereof. According to the preparation method provided by the invention, polyhydric alcohol is taken as a raw material, a long-chain alkane structure of the polyhydric alcohol is introduced into the polyurethane coating through a prepolymerization reaction, then reactive phosphorus-containing polyhydric alcohol is taken as a chain extender in a chain extension reaction, and a group with flame retardant property is introduced. The waterborne polyurethane emulsion which is stable, free of migration of flame-retardant elements and excellent in flame-retardant performance can be obtained, the waterborne polyurethane emulsion can be suitable for various fields such as fabric coatings and leather impregnation, and meanwhile the preparation method is simple, convenient and easy to implement and suitable for large-scal