SOLID CATALYST FOR PROPYLENE POLYMERIZATION AND A METHOD FOR PREPARATION OF POLYPROPYLENE USING THE SAME
A solid catalyst for propylene polymerization includes titanium, magnesium, halogen and a maleate compound as an internal electron donor. A method for preparing propylene using the catalyst is also described. According to the present invention, it is possible to prepare polypropylene having a wide molecular weight distribution.
1 . A solid catalyst for propylene polymerization, which comprises titanium, magnesium, halogen and maleate compounds represented by the following formula (II) as an internal electron donor:
wherein, R 1 , R 2 , R 3 and R 4 , which may be same or different from each other, are independently linear, branched or cyclic C1-20 alkyl, alkenyl, aryl, arylalkyl or alkylaryl group.
2 . The solid catalyst for propylene polymerization according to claim 1 , comprising magnesium 5-40 wt %, titanium 0.5-10 wt %, halogen 50-85 wt % and the internal electron donor 2.5-30 wt %.
3 . Method for preparing polypropylene comprising polymerizing propylene or copolymerizing propylene with other alpha-olefins, in the presence of a solid catalyst according to claim 1 , AlR 3 , wherein R is C1-6 alkyl group as a cocatalyst and R 1 m R 2 n Si(OR 3 ) (4-m-n) , wherein R 1 and R 2 , which are same or different, linear, branched or cyclic C1-12 alkyl or aryl group; R 3 is linear or branched C1-6 alkyl group; m and n are 0 or 1, respectively, provided that m+n is 1 or 2, as an external electron donor.
4 . Method for preparing polypropylene comprising polymerizing propylene or copolymerizing propylene with other alpha-olefins, in the presence of a solid catalyst according to claim 2 , AlR 3 , wherein R is C1-6 alkyl group as a cocatalyst and R 1 m R 2 n Si(OR 3 ) (4-m-n) , wherein R 1 and R 2 , which are same or different, linear, branched or cyclic C1-12 alkyl or aryl group; R 3 is linear or branched C1-6 alkyl group; m and n are 0 or 1, respectively, provided that m+n is 1 or 2, as an external electron donor.