Application of Mannich base in flame-retardant polyurethane material

A method for preparing a flame-retardant polyurethane material, comprising preparing a polyether polyol from a Mannich base, and preparing a flame-retardant polyurethane material from the polyether polyol, wherein the Mannich base has a structure represented by a formula (I):

• wherein, Ar is hydroxyl or hydroxyl substituted C1˜C16 alkyl, R
• is
• and X1, X2 and X3, independently of each other, represent a halogen,
• wherein the Mannich base is prepared by a method comprising the following steps:
• (1) performing a reaction by heating diethanolamine, then adding paraformaldehyde into the diethanolamine in batches, and controlling a temperature of 50-60° C., producing 3-hydroxyethyl-1,3-oxazolidine;
• and
• (2) performing a reaction by adding a phenyl compound into the 3-hydroxyethyl-1,3-oxazolidine, producing the Mannich base with a structure represented by the formula (I);
• wherein the phenyl compound has a structure represented by a formula (I′) as follows:
• wherein, Ar is hydroxyl or hydroxyl substituted C1˜C16 alkyl and X1, X2 and X3, independently of each other, represent a halogen.