Process for the preparation of polymer of 1-butene
A process for the preparation of 1-butene homopolymers or 1-butene/alpha olefin copolymers wherein the alpha olefins are selected from ethylene, propylene or alpha olefins of formula CH 2 ═CHZ wherein Z is a C 3 -C 20 alkyl radical, comprising contacting 1-butene or 1-butene and one or more alpha olefins under polymerization conditions in the presence of a catalyst system comprising: (a) a solid component comprising a Ti compound and an internal electron-donor compound supported on MgCl 2 (b) an alkylaluminum cocatalyst; and (c) a compound of formula (I) as external donor.
1. A process for the preparation of 1-butene homopolymers or 1-butene/alpha olefin copolymers comprising the step:
contacting
(i) 1-butene or
(ii) 1-butene and at least one alpha olefin wherein the alpha olefin is present in 0.1 to 20 mol % and wherein the alpha olefin is selected from ethylene, propylene or alpha olefins of formula CH 2 ═CHZ wherein Z is a C 3 -C 20 alkyl radical
with a catalyst system under polymerization conditions wherein the catalyst system comprises:
(a) a solid component comprising a Ti compound and an internal electron-donor compound supported on MgCl 2 ;
(b) an alkylaluminum cocatalyst; and
(c) a compound of formula (I) as external donor
wherein:
R 1 , R 2 , R 3 R 4 and R 5 equal to or different from each other, are hydrogen atoms or C 1 -C 20 hydrocarbon radicals; or two R 1 , R 2 , R 3 and R 4 can be joined to form a C 5 -C 20 , saturated or unsaturated ring.
2. The process according to claim 1 wherein in the compound of formula (I), R 1 , R 2 , R 3 and R 4 are hydrogen atoms or linear or branched, C 1 -C 20 -alkyl, or two R 1 , R 2 , R 3 , R 4 are joined to form a C 5 -C 10 saturated or unsaturated ring.
3. The process according to claim 1 wherein the internal donor is selected from alkyl, cycloalkyl or aryl esters of mono carboxylic acids, the said alkyl, cycloalkyl or aryl groups having from 1 to 18 carbon atoms.
4. The process according to claim 3 wherein the internal donors are C 1 - C 20 alkyl esters of phthalic acids.
5. The process according to claim 1 wherein the external electron donor compound (C) is fed in such an amount to give a molar ratio between the organoaluminum compound and said electron donor compound (Al/ED) higher than 2.
6. The process according to claim 5 wherein the molar ratio between the organoaluminum compound and the electron donor compound C (Al/ED) is between 4 and 1000.
7. The process of claim 3 wherein the internal donor is selected from benzoic acids, or polycarboxylic acids.
8. The process according to claim 4 wherein the internal donors are substituted C 1 -C 20 alkyl esters of phthalic acids.