Process for the production of copolymers of propylene and but-1-ene, products resulting therefrom and uses thereof

A process for the production of copolymers of propylene and but- 1-ene, wherein the proportion by weight of units derived from but-1-ene is from 10 to 40% and wherein the proportion, denoted by the symbol "PRE" of isolated ethyl branches is at least equal to the square of the proportion (P) of units derived from propylene which are contained in said copolymers, said process being characterized as a continuous process in which a gaseous mixture of propylene and but-1-ene is introduced into a fluidization vessel for admixture in a dry fluidized state with a catalytic system which is stereospecific in the polymerization of propylene alone and consists essentially of a solid titanium trichloride and one or more organo-metallic compounds of the metals of groups II and III of the periodic table of elements, continuously withdrawing unreacted monomers and solid polymer particles from the reaction vessel, separating unreacted monomers from the remainder, recycling separated unreacted monomer to the reaction vessel, and adding monomer for introduction with the recycle gaseous monomer in an amount to maintain relatively constant the ratio of monomers introduced into the reaction vessel for polymerization, and maintaining the fluidized materials in the reaction vessel under pressure of less than 40 bars during the polymerization reaction.