Propylene pentene-1 copolymers, its producing process and composition containing the same

The invention provides a copolymer of propylene and pentene, together with a process for producing such copolymer and a polymer composition. In the process, propylene and pentene are reacted in a reaction zone at a pressure of 60 kg/cm2 and temperature of 0-100° C. for 20-480 minutes in the presence of a Ziegler-Natta catalyst or catalyst system. The polymer composition has several components, namely the above copolymer, a phenolic stabilizer, an organic phosphite stabilizer, a thioether stabilizer and at least one metal salt of a higher aliphatic acid, with the proviso that at least one of the organic phosphite stabilizer, the thioether stabilizer and said salt must be present, so that up to two thereof can optionally be omitted.