Method for reducing expansion and shrinkage difference of base material for manufacturing multi-layer printed circuit board

The invention belongs to the technical field of circuit boards, and particularly relates to a method for reducing the expansion and shrinkage difference of a multi-layer printed circuit board manufacturing base material, a plurality of core layers and a press-fit heat conduction layer are included, each core layer comprises a base material and substrates arranged on the two sides of the base material, the core layers are used for circuit manufacturing and detection, and the press-fit heat conduction layer is arranged on the base material. The press-fit heat conduction layer comprises a second polypropylene layer and a press-fit copper foil layer; comprising the following steps that S1, a first polypropylene layer is arranged between every two adjacent core layers, and second polypropylene layers are arranged on the two sides of the outermost core layer; s2, arranging a laminated copper foil layer on the outer side of the second polypropylene layer to obtain a laminated plate; and S3, the laminated plate is pl