Claims
- 1. A process for preparing a propylene block copolymer, which comprises a first polymerization stage for homopolymerizing propylene or copolymerizing propylene with ethylene and/or α-olefin of 4 to 10 carbon atoms to prepare a crystalline polymer and a second polymerization stage for copolymerizing two or more monomers selected from α-olefin of 2 to 20 carbon atoms to prepare a low-crystalline or non-crystalline copolymer, in the presence of a catalyst for olefin polymerization comprising:(I) a prepolymerized catalyst obtained by prepolymerizing at least one reactive monomer represented by the following formula (I) or (ii) using (a) a solid titanium catalyst component containing magnesium, titanium, halogen and an electron donor as essential components, (b) an organometallic catalyst component and an organosilicon compound represented by the following formula (c-i); RnSi(OR′)4−n (c-i) wherein each of R and R is a hydrocarbon group, and n is a number satisfying the condition of 0<n<4, said reactive monomer being prepolymerized in an amount of 0.1 to 1,000 g per 1 g of the solid titanium catalyst component (a);H2C═CH—X (i) H2C═CH—CH2—X (ii) wherein X is a cycloalkyl group, an aryl group or M is carbon or silicon, R1 and R2 are each a hydrocarbon group, and R3 is hydrogen or a hydrocarbon group;(II) the organometallic catalyst component (b); and (III) a silicon compound represented by the following formula (iii) or a compound having at least two ether linkages existing via plurality of atoms: Ran—Si—(ORb)4−n (iii) wherein, n is 1, 2 or 3; when n is 1, Ra is a secondary or a tertiary hydrocarbon group; when n is 2 or 3, at least one of Ra is a secondary or a tertiary hydrocarbon group, Ra may be the same or different, and Rb is a hydrocarbon group of 1 to 4 carbon atoms; and when 4−n is 2 or 3, Rb may be the same or different.
Parent Case Info
This application is a division of applicants copending application Serial No. 08/351,548, filed Dec. 7, 1994, now U.S. Pat. No. 6,274,678, which is a continuation of application Ser. No. 08/164,757, filed Dec. 10, 1993, now abandoned, which is a division of application Ser. No. 08/094,977, filed Jul. 22, 1993, now abandoned to all of which applicants claim priority.
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Continuations (1)
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Number |
Date |
Country |
Parent |
08/164757 |
Dec 1993 |
US |
Child |
08/351548 |
|
US |