Polypropylene resin composition and monolayer and multilayer film

A polypropylene resin composition, comprising a propylene polymer (A) satisfying the following requirement (a);

• a soft propylene copolymer (B) satisfying the following requirement (b);
• and
• a polyolefin (C) selected from polypropylene and an ethylene propylene α-olefin copolymer and containing a structural unit derived from an unsaturated carboxylic acid and/or a derivative thereof, and having 95 to 100 mol % of a content proportion of the structural unit derived from propylene in the structural units excluding the structural unit derived from the unsaturated carboxylic acid and/or the derivative, wherein
• the polyolefin (C) contains 0.05 to 5% by mass of the structural unit derived from an unsaturated carboxylic acid and/or a derivative thereof,
• the propylene resin composition contains 2 to 10 parts by mass of the polyolefin (C) (provided that a total of (A), (B), and (C) is 100 parts by mass),
• (a) a melting point observed by differential scanning calorimetry is 100° C. or more, and
• (b) an MFR measured at 230° C. and a load of 2.16 kg according to ASTM D-1238 is in the range of 0.01 to 100 g/10 min, and at least one of the following requirements (b-1) and (b-2) is satisfied:
• (b-1) a syndiotactic triad fraction (rr fraction) measured by 13C-NMR is 60% or more, and
• (b-2) a structural unit derived from propylene is contained at 55 to 90 mol % and a structural unit derived from at least one olefin selected from α-olefins having 2 to 20 carbon atoms (excluding propylene) is contained at 10 to 45 mol % (provided that a total of the structural unit derived from propylene and the structural units derived from α-olefins having 2 to 20 carbon atoms (excluding propylene) is 100 mol %), and relation between a intrinsic viscosity [η] (dL/g) measured at 135° C. in decalin and the MFR (g/10 min, 230° C., load:
• 2.16 kg) satisfies the relation represented by an expression:
• 1.50×MFR−0.20≤[η]≤2.65×MFR−0.20.