Preparation method of white matte polyimide film

The invention discloses a preparation method of a white matt polyimide film, which comprises the following steps of: adopting bicyclo [2, 2, 2] octyl-7-ene-2, 3, 5, 6-tetracarboxylic dianhydride (BCDA), 2, 3, 5, 6-tetracarboxylic dianhydride (BCDA), 2, 3, 5, 6-tetracarboxylic dianhydride (BCDA), 2, 3, 5, 6- The preparation method comprises the following steps: by taking BCDA as a raw material, 2, 2 ', 5, 5'-dimethyl-[1, 1 ': 4', 1 '-terphenyl]-4, 4'-diamine (TMTD), titanium dioxide white powder and silicon dioxide matting powder as raw materials, reacting BCDA with TMTD in an aprotic polar solvent gamma-butyrolactone in a nitrogen protection environment, adding the white powder and the matting powder in an intermediate step, and controlling the final molar ratio of dianhydride to diamine to be (0.98-0.995): 1; and filtering the obtained resin, carrying out vacuum defoaming, uniformly coating a glass substrate with the resin, and carrying out wet film preparation and imidization to obtain the final white matte