Polyimide resin and preparation method thereof

The invention discloses polyimide resin and a preparation method thereof, the resin is thermoplastic crystalline resin, and is obtained by copolycondensation of special aromatic diamine 4, 4 '-bis (3-aminophenoxy) biphenyl, another aromatic diamine monomer, a dianhydride monomer and an end-capping reagent. The logarithmic viscosity of the liquid crystal composition is 0.25-0.95 dL/g, and the glass transition temperature of the liquid crystal composition is 210-410 DEG C. The polyimide resin product can be used for a long time at 240 DEG C, and compared with a PI product with the same temperature-resistant grade, the polyimide resin product has the advantages of excellent processability, good film-forming property and good fiber-forming property, can meet extrusion and injection molding conditions, is expected to be widely applied to the fields of engineering plastics, films, fibers and the like, and is especially suitable for manufacturing light high-temperature-resistant precision parts. 本发明公开了一种聚酰亚胺树脂及其制备方法