Environment-friendly polyurethane flame-retardant glue and preparation method thereof

The invention discloses environment-friendly polyurethane flame-retardant glue and a preparation method thereof. The invention relates to a polyester polyol, which is prepared from the following components in parts by mass: 20.5 to 25.7 parts of polyester diol; 24.6 to 30.8 parts of diisocyanate; 0.5 to 0.56 part of a stepwise polymerization reaction catalyst; 4.6 to 5.7 parts of a hydrophilic chain extender; 1.1 to 1.5 parts of a cross-linking agent; 11.2 to 20.9 parts of acetone; 22.4 to 28.4 parts of emulsified water; in the synthesis process of the product, bio-based 2, 5-dimethylolfuran is used as a raw material to synthesize polyester diol, a petroleum-based product is replaced, energy conservation and environmental protection are achieved, and the product 2, 5-dimethylolfuran has excellent flame retardant property and participates in the synthesis process of the product as a reactant, so that the production cost is reduced, and the production efficiency is improved. Under the condition that the structu