Modified polyolefin resin composition

An unsaturated carboxylic acid-modified polyolefin resin composition consisting essentially of polypropylene modified with an unsaturated carboxylic acid and satisfying the following formulae (I) and (II) with respect to a small-angle X-ray scattering which is incident perpendicularly on said composition melted at 170° C.:

• when a wave number vector (s) is in the range of 0.003 Å−1 to 0.006 Å−1,
• −5.0≦A≦−3.0 (I)
• wherein A represents a gradient of a characteristic curve obtained by plotting logarithms of a corrected scattering intensity (I1(s)) on Y (ordinate) axis and the wave number vector (s) on X (abscissa) axis, and wherein said corrected scattering intensity (I1(s)) is a value obtained by subtracting a product of an air scattering intensity and an X-ray transmittance and a background intensity based on thermal diffuse scattering, from the small-angle X-ray scattering intensity:
• 0.001≧Qn/P≧0.0001 (II)
• wherein Qn and P are values calculated from the following formulae (1) and (2):
• Qn = ∫ 0.003 0.007 ⁢ s 2 ⁢ I 1 ⁡ ( s ) ⁢ ⅆ s / ∫ 0.02 0.04 ⁢ s 2 ⁢ I 2 ⁡ ( s ) ⁢ ⅆ s ( 1 )
• wherein s is a wave number vector, I1(s) is a corrected scattering intensity, and I2(s) is a scattering intensity at 170° C. of polyolefin before modification, P = ∫ 0.003 0.007 ⁢ s 2 ⁢ I 1 ⁡ ( s ) ⁢ ⅆ s / M ( 2 )
• wherein M is an average value of s4I1(s) when s is in the range of 0.003 Å−1 to 0.004 Å−1.