Polypropylene composition for buried drainage pipelines and preparation method thereof

The invention discloses a polypropylene composition for buried drainage pipelines and a preparation method thereof. The polypropylene composition comprises the following components by weight: 100 parts of ethylene-propylene block copolymer polypropylene resin, 0.6-0.7 part of an antioxidant, 0.05-0.1 part of a nucleating agent and 0.15 part of a processing aid. In the ethylene-propylene block copolymer polypropylene resin, the ethylene content measured according to C13 nuclear magnetic resonance is 3.5%-4.3%, the mm structure content in a propylene continuous three-unit (PPP) sequence is 91.8mol%-93.1mol%, the mmmm structure content in a propylene continuous five-unit (PPPPP) sequence is 89.3mol%-91.2mol%, the number-average molecular weight measured according to a GPC method is 9.2-11.4 thousand, and the weight average molecular weight is 640,000-750,000. The polypropylene composition provided by the invention enables the buried drainage pipelines to have high rigidity and high toughness. 本发明公开了一种用于埋地排水管道的聚丙