US Patent 7470757 Olefin polymerization process in the presence of an anti-fouling agent

An olefin polymerisation process carried out in the presence of an anti-fouling agent and a chromium-type catalyst or Ziegler Natta catalyst; characterised in that the anti-fouling agent comprises an anti-fouling polymer having an average molecular weight (Mw) of greater than 1000 daltons and containing: (1) one or more blocks —(CH2—CH2—O)k— where each k is in the range from 1 to 50; and (2) one or more blocks —(CH2—CH(R)—(O)n− where R comprises an alkyl group having from 1 to 6 carbon atoms and each n is in the range from 1 to 50, and terminated by a R′ and a R″ end groups, wherein R′ is OH or an alkoxy having from 1 to 6 carbon atoms and R″ is H or an alkyl having from 1 to 6 carbon atoms.