The present invention relates to a process for preparing a propylene
random copolymer comprising polymerization of propylene with a comonomer,
said comonomer being ethylene or an .alpha.-olefin comprising at least
four carbon atoms, in the presence of a catalyst in a multistage process
comprising polymerization of propylene with a comonomer in a first
reaction zone including at least one slurry reactor to give a first
polymerization product, transferring said first product to a second
reaction zone including at least one gas phase reactor and
polymerisations of propylene with a comonomer in said gas phase reactor
in the presence of said first polymerization product, wherein the
temperature in the gas phase reactor is at least 10.degree. C. higher
than in the slurry reactor and to a polymer obtainable by this process.
Furthermore, the invention relates to a propylene random copolymer
prepared by copolymerization of propylene with a comonomer wherein the
distribution of the comonomer determined according to the TREF method is
multimodal, preferably bimodal, a propylene random copolymer prepared by
copolymerization of propylene with a comonomer wherein the copolymer is
having an elution interval determined according to the TREF method of
50.degree. C. or more, a propylene random copolymer prepared by
copolymerization of propylene with a comonomer, wherein the random
copolymer is a unimodal polymer and the elution interval determined by
the TREF method is given by the equation Y.ltoreq.4.5m+16 wherein Y is
the elution interval in .degree. C. and m is the percentage of ethylene
in the copolymer in wt. %, and to the use of such a copolymers for the
production of a film, of an article by blow moulding or injection
moulding, of a fiber or of a pipe.