Patent ID: 6214939
Filing Date: 2001-04-10
Classification: C08F,Y02P,Y10S

Abstract:
A process for preparing a propylene block copolymer, comprising the steps of polymerizing propylene to form a polypropylene component and a step of copolymerizing ethylene and an .alpha.-olefin of 3 to 20 carbon atoms to form an ethylene/.alpha.-olefin copolymer component in an optional order, wherein the polymerizing and copolymerizing steps are carried out in the presence of an olefin polymerization catalyst (3) formed from:(I-3) a contact product obtained by contacting:(A) a solid titanium catalyst component comprising magnesium, titanium, halogen and an electron donor,(B) an organometallic compound catalyst component, and(D) a compound having at least two ether linkages spaced by plural atoms;(II-3) (D) a compound having at least two ether linkages spaced by plural atoms; and optionally,(III) an organometallic compound catalyst component,the polymerizing step to form the polypropylene component and the copolymerizing step to form the ethylene/.alpha.-olefin copolymer component are carried out using (I-3) the contact product in an amount of about 0.0001 to 50 mmol, in terms of titanium atom, based on 1 liter of the polymerization volume, (II-3) (D) the compound having at least two ether linkages in an amount of 0.001 to 5,000 mol and the organometallic compound catalyst component (III), when it is used, in an amount of 1 to 2,000 mol. both based on 1 mol of the titanium atom, at a temperature of about -50 to 200.degree. C. and a pressure of atmospheric pressure to 100 kg/cm.sup.2 ; and wherein the resulting propylene block copolymer has the following properties:(i) a pentad isotacticity (M.sub.5) of a boiling heptane-insoluble component in said copolymer determined by the following formula (1) using a .sup.13 C-NMR spectrum is not less than 0.97: ##EQU8##wherein(Pmmmm) is absorption intensity of methyl groups on a third propylene units in five propylene unit sequences where the five units are bonded isotactically to each other,(Pw) is absorption intensity of all methyl groups in propylene units,(S.alpha..gamma.) is absorption intensity of secondary carbons in a main chain, with the proviso that one of two tertiary carbons nearest to each of said secondary carbons is situated at the .alpha. position and the other is situated at the .gamma. position,(S.alpha..delta..sup.+) is absorption intensity of secondary carbons in a main chain, with the proviso that one of two tertiary carbons nearest to each of said secondary carbons is situated at the .alpha. position and the other is situated at the .delta. or farther position, and(T.delta..sup.+.delta..sup.+) is absorption intensity of tertiary carbons in a main chain, with the proviso that one of two tertiary carbons nearest to each of said tertiary carbons is situated at the .delta. or farther position and the other is also situated at the .delta. or farther position;a pentad tacticity (M.sub.3) of the boiling heptane-insoluble component determined by the following formula (2) using a .sup.13 C-NMR spectrum is in the range of 0.0020 to 0.0050; ##EQU9##wherein, (Pw), (S.alpha..gamma.), (S.alpha..delta..sup.+) and (T.delta..sup.+.delta..sup.+) have the meanings as defined in the formula (1),(Pmmrm) is absorption intensity of methyl groups on third propylene units in five propylene unit sequences represented by .right brkt-bot..right brkt-bot..right brkt-bot..right brkt-top..right brkt-top. in which .right brkt-bot. and .right brkt-top. are each a propylene unit,(Pmrmr) is absorption intensity of methyl groups on third propylene units in five propylene unit sequences represented by .right brkt-bot..right brkt-bot..right brkt-top..right brkt-top..right brkt-bot. in which .right brkt-bot. and .right brkt-top. are each a propylene unit,(Pmrrr) is absorption intensity of methyl groups on third propylene units in five propylene unit sequences represented by .right brkt-bot..right brkt-bot..right brkt-top..right brkt-bot..right brkt-top. in which .right brkt-bot. and .right brkt-top. are each a propylene unit,(Prmrr) is absorption intensity of methyl groups on third propylene units in five propylene unit sequences represented by .right brkt-top..right brkt-bot..right brkt-bot..right brkt-top..right brkt-bot. in which .right brkt-bot. and .right brkt-top. are each a propylene unit,(Prmmr) is absorption intensity of methyl groups on third propylene units in five propylene unit sequences represented by .right brkt-top..right brkt-bot..right brkt-bot..right brkt-bot..right brkt-top. in which .right brkt-bot. and .right brkt-top. are each a propylene unit,(Prrrr) is absorption intensity of methyl groups on third propylene units in five propylene unit sequences represented by .right brkt-bot..right brkt-top..right brkt-bot..right brkt-top..right brkt-bot. in which .right brkt-bot. and .right brkt-top. are each a propylene unit; and(ii) a 23.degree. C. n-decane-soluble component in said copolymer has an intrinsic viscosity (.eta.), as measured in decahydronaphthalene at 135.degree. C., of not less than 4 dl/g.