Patent ID: 7517938

Claim:
A process for polymerizing, in a first polymerization, ethylene or a mixture of ethylene with at least one olefinic monomer selected from propylene, 1-butene, 1-pentene, 1-hexene, or 1-octene in a first loop reactor in the presence of a polymerization catalyst at from 20 to 150° C., but below the melting point of a polymer to be formed, and a pressure of from 43 to 80 bar, wherein the polymer formed is present in a suspension in a liquid or supercritical suspension medium, wherein the suspension is circulated by means of an axial pump, wherein the polymerization is carried out at an average solids concentration in the reactor of more than 53% by weight, based on the total mass of the contents of the reactor, in the case of continuous product discharge, and at an average solids concentration in the reactor of more than 45% by weight, based on the total mass of the contents of the reactor, in the case of discontinuous product discharge, and wherein the polymerization is carried out at an ethylene concentration of at least 10 mol %, based on the suspension medium.