Propylene polymer-based composite film, preparation method therefor, and application thereof

A propylene polymer-based composite film, comprising at least layer a and layer b that are different from each other;

• wherein each of layer a and layer b comprises at least one propylene polymer, and
• at least one layer among layer a and layer b comprises a propylene impact copolymer;
• wherein the propylene impact copolymer comprises an elastic part, the elastic part being in the form of a plurality of strip-like rubber phases dispersed in the composite film, said plurality of rubber phases are arranged parallel to each other and each has an average size of the transverse axis of 20-200 nm and an average value of the aspect ratio of 5-20, as determined by observing the cross section of the composite film cut along the transverse direction (TD) via an atomic force microscope,
• said propylene impact copolymer comprises a propylene homopolymerized part and a copolymerized part comprising ethylene units, and the copolymerized part comprising ethylene units is the elastic part, and
• wherein the composite film has a film haze of less than 7%.