The present invention provides a preparation method of a
polypropylene foaming plate or sheet. According to the preparation method, high melt strength homopolymerization
polypropylene is adopted as a matrix resin and a
foaming agent is adopted to foam to prepare the
polypropylene foaming plate or sheet, wherein the homopolymerization polypropylene preparation method comprises: in two or more than two reactors having the series connection operation, carrying out a two-stage or multi-stage propylene homopolymerization reaction, wherein the external
electron donors used in the two-stage reaction are respectively a
silane compound and a diether compound. According to the present invention, the high melt strength polypropylene having the wide molecular
weight distribution is adopted as the
raw material to achieve the stabilization of the polypropylene
raw material, such that the foaming window is effectively expanded, the process is easy to adjust, the polypropylene foaming plate or sheet having the smooth self-skinning, the uniform foam hole
diameter, the closed hole
rigid structure, the density of 0.2-0.9 g / cm<3> and the thickness of 0.1-400 mm can be prepared, and the polypropylene foaming plate or sheet can be widely used in the fields of heat-insulation tableware, automotive interiors, building templates, camping supplies, decoration material sandwiches, product vibration reduction packaging and the like.