The invention discloses a preparation method of a multi-layer low-gloss black
polyimide thin film. The preparation method comprises the following main steps: I, preparing a
polyamide acid film; II, preparing a black blending
polyamide acid resin solution; III, evenly
coating the upper and / or lower surface of the
polyamide acid film with the black blending polyamide acid resin solution, heating andcuring to obtain a multi-layer black polyamide acid film; IV, and stretching in two ways, conducting imidization and
sizing to obtain the multi-layer low-gloss black
polyimide thin film. The preparation of the black blending polyamide acid resin solution in the step II comprises the following steps: preparing the polyamide acid resin solution, a black
slurry and a delustrant dispersion solution,adding a flocculant into the three, blending, stirring at the low temperature, defoaming, preheating, and agglomerating. The average particle size of a black
pigment and a delustrant is 0.01-0.8 [mu]m, the delustrant is added into the condensation
polymerization synthesis process of a polyamide acid resin, and the light
transmittance, the glossiness, the electrical property and the physical and
mechanical property of the obtained multi-layer thin film are obviously improved.