Branched propylene-based polymer and production method therefor

A branched propylene-based polymer having the following properties (1) to (5):

• property (1):
• a melt flow rate (MFR) measured at a temperature of 230° C. and a load of 2.16 kg is 10 g/10 min or more and 100 g/10 min or less;
• property (2):
• a ratio (Mw/Mn) between a weight average molecular weight (Mw) and a number average molecular weight (Mn), both of which are obtained by gel permeation chromatography (GPC), is 2.5 or more and less than 3.5;
• a ratio (Mz/Mw) between a z average molecular weight (Mz) and a weight average molecular weight (Mw), both of which are obtained by GPC, is 3.0 or more and 4.7 or less;
• and the z average molecular weight (Mz) is 50.0×104 or more and 94.0×104 or less;
• property (3):
• in an integral molecular weight distribution curve obtained by GPC, a percentage (W100×104) of a component having a molecular weight of 100×104 or more, is 1.5 mass % or more and 4.0 mass % or less;
• property (4):
• in a molecular weight distribution curve obtained by 3D-GPC, a branching index g′(100×104) at an absolute molecular weight M a b s of 100×104 is more than 0.70 and 0.85 or less;
• and
• property (5):
• a ratio [η*(0.01)/η*(100)] between a complex viscosity η*(0.01) at an angular frequency ω of 0.01 rad/s (ω=0.01 rad/s) and a complex viscosity η*(100) at an angular frequency ω of 100 rad/s (ω=100 rad/s) in dynamic viscoelasticity measurement, is 4.0 or more and 20 or less, and η*(0.01)/η*(100) and the MFR satisfy the following formulae (1) and (2):
• η*(0.01)/η*(100)≤−21×Log(MFR)+45 Formula (1)
• η*(0.01)/η*(100)≥−21×Log(MFR)+38 Formula (2).