Polypropylene composition and preparation method thereof, and polymer film

The invention relates to the field of a propylene polymer and discloses a polypropylene composition and a preparation method thereof, and a polymer film. The polypropylene composition comprises a random copolymer; in the random copolymer, the content of a structure unit from 1-butene is 10 to 20 percent by weight, the content of a structure unit from propylene is 80 to 90 percent by weight and thecontent of a structure unit from ethylene is 0 to 5 percent by weight when the total weight of the random copolymer is 100 percent by weight. In the polypropylene composition provided by the invention, the content of an N-hexane soluble substance is low; and the polymer film prepared by using the polypropylene composition has low initial heat sealing temperature, low haze, high light transmittance and high specular glossiness. 本发明涉及丙烯聚合物领域，公开了种聚丙烯组合物及其制备方法、由该方法制备得到的聚丙烯组合物和种聚合物膜。聚丙烯组合物含有无规共聚物，以所述无规共聚物的总重量为100重量％时，在所述无规共聚物中，来自于1-丁烯的结构单元的含量为10-20重量％，来自于丙烯的结构单元的含量为80-90重量％，来自于乙烯的结构单元的含量为0-5重量％。本发明提供的聚丙烯组合物正己烷可溶物的含量低；采用本发