To provide propylene random copolymers capable of producing films and sheets which exhibit excellent low temperature heat-sealing properties equal to those of straight chain low density polyethylenes and are excellent in antiblock properties, slip characteristics and rigidity as well without adversely affecting the favorable properties inherent in polypropylene films and sheets and compositions thereof.

In a copolymer of propylene and a ≥5 α-olefin, the copolymer is characterized I that the melting point [Tm(°C)] of the copolymer measured by a differential scanning calorimeter and the content [α(mol.%)] of the ≥5 α-olefin units in the copolymer satisfy the formula: Tm≤140 and Tm≤160-7α and the crystallization temperature [Tc(°C)] of the copolymer [Tm(°C)] and the melting point [Tm(°C)] satisfy the formula: Tc≥0.75Tm-15.