PURPOSE: To provide the titled compsn. which can form a laminated sheet having excellent low-temperature heat sealing properties and high strength when laminated on the surface of a crystalline PP substrate, containing a crystalline random propylene copolymer and a random 1-butene copolymer.

CONSTITUTION: The titled compsn. contains a crystalline random propylene copolymer (A) composed of a major portion of propylene and a minor portion of an α-olefin other than propylene and a random 1-butene copolymer (B) composed of a 1-butene component and a 5C or higher α-olefin component. Component B is composed of 50W99mol% of the 1-butene component and 50W1mol% of the α-olefin component and has an intrinsic viscosity η of 0.5W6dl/g (at 135°C in decalin), a m.p. Tm of 30W120°C as measured with a differential scanning calorimeter, crystallinity of 5W60% as measured by X-ray diffraction a boiling methyl acetate soluble content W1 of 2wt% or below and a content W2 of acetone/n-decane solvent mixture (1:1 by volume) solubles at 10°C of less than 5×[η]-1.2wt%.