VERFAHREN ZUR POLYMERISATION UND KOPOLYMERISATION VON OLEFINE

Method of prodn. of a homopolymer of propylene or a copolymer of polypropylene with up to 20 wt. % polyethylene, by polymerisation in the presence of a catalyst system and a silane. The process comprises two final stages (a) and (b) where polypropylene with a wt. average mol. wt. of 350,000-4,000,000 and 50,000-340,000 is produced. The final product has a wt. average mol. wt. 150,000-1,500,000 and comprises at least 50 wt. % (a) and (b) with Mw/Mn = 6.0. The silane pref. is diisopropyldimethoxysilane, diisobytylmethoxysilane, t-butyltrimethoxysilane or di-t-butyldimethoxysilane. The catalyst system comprise a solid HC insol. composite of a Ti-contg. component on a Mg-contg. cpd. with a co-catalyst of a Gp. II or III metal alkyl. The catalyst system may opt. comprise an organic ester such as alkyl, alicyclic, alkenyl, aryl, alkaryl, aralkyl mono-, di- or tri-ester of an aliphatic or aromatic carboxylic acid or a substd. aromatic carboxylic acid. The mol. wt. is controlled by diethyl zinc or H2 is pref. in stages (a) and (b). Polymerisation is performed in the gas phase or in the slurry phase where the liq. comprises an alkane, cycloalkane, alkylaromatic, halogenated or hydrogeated aromatic, a high mol. wt. paraffin or mixt. thereof.