Phosphor-containing nitrogen-containing structural type flame retardant polyhydric alcohol as well as preparation method and application thereof

The invention discloses a phosphor-containing nitrogen-containing structural type flame retardant polyhydric alcohol as well as a preparation method and application thereof, and relates to a flame retardant polymer. The preparation method comprises the following steps of carrying out heat-up reaction on paraformaldehyde and ethanol amine under protection of a nitrogen gas after mixing and reacting, then, adding alcohol liquor of aromatic phenol compounds, and refluxing and reacting to obtain an Mannich polyhydric alcohol intermediate; adding phosphite ester compounds to continuously react with paraformaldehyde after cooling the temperature of the system to 50 DEG C-55 DEG C, removing alcohol and moisture produced by reaction by distilling under reduced pressure to obtain a product. The phosphor-containing nitrogen-containing structural type flame retardant polyhydric alcohol can be applied to manufacturing hard polyurethane foam plastic. A benzene ring structure with good thermal stability and P, N flame-retardant elements are introduced into a PU (poly urethane) structure by virtue of a chemical bond mode by using the polyhydric alcohol without a mobility problem, so that lasting flame resistance is realized on the condition of ensuring material processing performances. A catalyst is not used for synthesizing the flame retardant polyhydric alcohol, materials are cheap and easily available, process is simple; and the retardant polyhydric alcohol is easy for industrial production without producing pollutants, and satisfies environment-friendly requirements.