Patent ID: 7183332

Claim:
A process for preparing porous olefin polymers, having a porosity of greater than 0.54 cc/g, comprising putting into contact in a polymerization reactor having a reactor temperature initially at a temperature T 1 , one or more olefins of formula CH 2 ═CHR 1 , R 1 being hydrogen, a C 1 –C 20 -alkyl or a C 6 –C 12 -aryl group with a catalyst obtained by reacting a solid catalyst component in the form of spheroidal particles comprising a compound of Ti or V not containing metal -π bonds and a Mg halide, optionally containing one or more electron donor compounds, with an aluminum-alkyl (Al-alkyl) compound, then raising the reactor temperature up to a polymerization temperature, wherein (I) if the temperature T 1 is lower than 40° C., the reactor temperature is raised up to the polymerization temperature in such a way that, for a time of at least one minute after the introduction of the catalyst system into the reactor, the reactor temperature is raised up to T 2 under the following condition: T 2 - T 1 m > 10 wherein m is the time, expressed in minutes, employed for reaching the temperature T 2 ; or (II) if the temperature T 1 is 40° C. or higher, the reactor temperature is maintained for a time of at least one minute at a temperature ranging from 45° C. to 65° C., wherein the process produces at least about 500 grams of the porous olefin polymers per gram of the solid catalyst component.