Multistage process for the (CO) polymerization of olefins
AssigneeMontell Technology Company BV
InventorsGabriele Govoni, Mario Sacchetti, Stefano Pasquali
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Abstract
Multistage process for the polymerization of olefins CH.sub.2 .dbd.CHR, where R is hydrogen or an alkyl, cycloalkyl or aryl radical with 1-10 carbon atoms, comprising two stages of polymerization. In a first stage, in the presence of a titanium or a vanadium catalyst and working in one or more reactors, an olefinic polymer with particular values of porosity is prepared; in a second stage, in the presence of the said porous polymer and a metallocene compound and/or their reaction products, one or more olefins, that are equal to or different from those polymerized in the first stage, are polymerized in one or more reactors.
Claims22
Process for the polymerization of one or more olefins CH.sub.2 .dbd.CHR, where R is hydrogen or an alkyl, cycloalkyl or aryl radical with 1-10 carbon atoms, characterized in that it comprises:
- (I) a first stage of polymerization, in which one or more of said olefins CH.sub.2 .dbd.CHR are polymerized, in one or more reactors, in the presence of a catalyst comprising the product of the reaction between an Al-alkyl compound and a solid component comprising at least one compound of a transition metal M.sup.I selected from Ti and V and not containing M.sup.I -.pi. bonds and a Mg halide in active form, said catalyst being capable of producing an olefin polymer having porosity, expressed as percentage of voids, greater than 5%;
- (II) a treatment stage, in which the product obtained in said first stage of polymerization (I) is contacted with a compound of a transition metal M selected from Ti, V, Zr and Hf containing at least one M-.pi. bond and optionally with an alkyl-Al compound;
- (III) a second stage of polymerization, in which one or more of the said olefins CH.sub.2 .dbd.CHR are polymerized, in one or more reactors, in the presence of the product obtained in said stage (II).
Process for the preparation of heterophase copolymers of propylene comprising at least two stages of polymerization in which:
- (A) in at least one reactor, propylene or its mixtures with ethylene and/or one or more olefins CH.sub.2 .dbd.CHR.sup.II, where R.sup.II is a hydrocarbon radical with 2-10 carbon atoms, are polymerized in the presence of a catalyst comprising the product of the reaction between an alkyl-Al compound, optionally an electron-donor compound and a solid component comprising at least one compound of a transition metal M.sup.I selected from Ti and V and not containing M.sup.I -.pi. bonds, a halide of magnesium in active form and optionally an electron-donor compound obtaining an olefinic polymer having porosity, expressed as percentage of voids, greater than 5%, content of units derived from the ethylene and/or from the CH.sub.2 .dbd.CHR.sup.II olefin less than 20% by weight, content of units derived from the propylene greater than 80% by weight and insolubility in xylene higher than 60%;
- (B) the product obtained in said stage (A) is contacted with a compound of a transition metal M selected from Ti, V, Zr and Hf containing at least one M-.pi. bond and optionally an alkyl-Al compound;
- (C) in at least one reactor, one or more olefins CH.sub.2 .dbd.CHR, where R is hydrogen or an alkyl, cycloalkyl or aryl radical with 1-10 carbon atoms, are polymerized in the presence of the product obtained in said stage (B), obtaining a substantially amorphous olefinic (co)polymer in a quantity of between 20 and 80% by weight relative to the total amount of the polymer produced in stages (A) and (C).
Dependencies are inferred from the claim text.