Process for producing propylene polymer compositions

Patent metadata

Field	Value
Publication number	US-10233271-B2
Application number	US-201615578599-A
Country	US
Kind code	B2
Filing date	Jun 10, 2016
Priority date	Jun 12, 2015
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

The present invention relates to a process for producing polypropylene polymer composition by polymerizing propylene with a C4 to C8 a-olefin comonomer and with ethylene in a sequential polymerization process with at least two reactors connected in series in the presence of a solid Ziegler-Natta catalyst component being free of external carrier material and any phthalic compounds, and wherein the C4 to C8 a-olefin comonomer content in the propylene polymer composition is at least 4.5 wt-%.

First claim

The invention claimed is:

1. A process for the preparation of propylene polymer compositions (P) by polymerizing propylene with a C4 to C8 α-olefin comonomer and ethylene in a sequential polymerization process comprising at least two reactors connected in series, wherein said process comprises the steps of:
(A) polymerizing in a first reactor (R-1) propylene, optionally a C4 to C8 α-olefin comonomer and optionally ethylene, and obtaining a propylene polymer fraction (A),
(B) transferring said propylene polymer fraction (A), optionally with unreacted propylene monomers and optionally with the unreacted ethylene and C4 to C8 α-olefin comonomers from the first reactor into a second reactor (R-2),
(C) feeding to said second reactor (R-2) additional propylene, optionally additional C4 to C8 α-olefin comonomer and optionally additional ethylene,
(D) polymerizing propylene, optionally C4 to C8 α-olefin comonomer and optionally ethylene in said second reactor (R-2), in the presence of said propylene polymer fraction (A), and
obtaining the propylene polymer composition (P) comprising the propylene polymer fraction (A) and a propylene polymer fraction (B) produced in said second reactor (R-2),
wherein the C4 to C8 α-olefin and the ethylene comonomers are fed at least to one of the reactors (R-1) and (R-2), and wherein the propylene composition (P) is a terpolymer that comprises C4 to C8 α-olefin comonomer in an amount of at least 4.5 wt-%, and
wherein,
the polymerization takes place in the presence of a solid catalyst component (SC),
i) having a surface area measured according to ASTM D 3663 of less than 20 m 2 /g,
ii) that is free of any external carrier material, and
iii) comprising:
(a) a transition metal compound selected from one of the groups 4 to 6 of the periodic table (IUPAC),
(b) a compound of a metal selected from one of the groups 1 to 3 of the periodic table (IUPAC), and
(c) a non-phthalic internal electron donor (ID), and

wherein said solid catalyst component (SC) does not contain any phthalic compounds.

2. The process according to claim 1 , wherein the non-phthalic internal electron donor (ID) is selected from (di)esters of non-phthalic (di)carboxylic acids, 1,3-diethers, and derivatives thereof.

3. The process according to claim 1 wherein the transition metal compound is a compound of the group 4 metal and the compound of a group 1 to 3 metal is compound of group 2 metal.

4. The process according to claim 1 , wherein the catalyst comprises a cocatalyst of an organoaluminium compound and an external donor selected from silanes of the general formula:
R a p R b q Si(OR c ) (4-p-q)
wherein R a , R b and R c are chosen independently from one another and can be the same or different and denote a linear alkyl or cycloalkyl group, and wherein p and q are numbers ranging from 0 to 3 with their sum p+q being equal to or less than 3.

5. The process according to claim 1 , wherein the first reactor (R-1) is a slurry reactor and the second reactor (R-2) is a gas phase reactor.

6. The process according to claim 1 , wherein in the first reactor (R-1) the polymerization temperature is in the range of 60° C. to 85° C., and in the second reactor (R-2) the polymerization temperature is in the range of 65° C. to 85° C.

7. The process according to claim 1 , wherein the propylene polymer composition (P) is a terpolymer having a C4 to C8 α-olefin comonomer content in the range of 4.5 wt % to 14 wt %, and ethylene content in the range of 0.5 to 3.0 wt-%.

8. The process according to claim 1 , wherein the propylene terpolymer composition has a combined content of ethylene and C4 to C8 α-olefin comonomer in the range of 5.0 to 17 wt %.

9. The process according to claim 1 , wherein the C4 to C8 α-olefin comonomer is 1-butene or 1-hexene.

10. The process according to claim 1 , wherein the catalyst is prepared by a method comprising:
a) providing a solution of:
a 1 ) at least a Group 2 metal alkoxy compound (Ax), the Group 2 metal alkoxy compound (Ax) being the reaction product of a Group 2 metal compound and an alcohol (A) comprising in addition to the hydroxyl moiety at least one ether moiety optionally in an organic liquid reaction medium; or
a 2 ) at least a Group 2 metal alkoxy compound (Ax′), the Group 2 metal alkoxy compound (Ax′) being the reaction product of a Group 2 metal compound and an alcohol mixture of the alcohol (A) and a monohydric alcohol (B) of formula ROH, where R is an alkyl of 2 to 16 C-atoms, optionally in an organic liquid reaction medium; or
a 3 ) a mixture of the Group 2 metal alkoxy compound (Ax) and a Group 2 metal alkoxy compound (Bx) that is the reaction product of a Group 2 metal compound and the monohydric alcohol (B), optionally in an organic liquid reaction medium; or
a 4 ) Group 2 metal alkoxy compound of formula M(OR 1 ) n (OR 2 ) m X 2-n-m or mixture of Group 2 alkoxides M(OR 1 ) n′ X 2-n′ and M(OR 2 ) m′ X 2-m′ where M is Group 2 metal, X is halogen, R 1 and R 2 are different alkyl groups of C 2 to C 16 carbon atoms, and 0<n<2, 0<m<2 and n+m<2, provided that both n and m are not simultaneously zero, 0<n′<2 and 0<m′<2; and

b) adding said solution from step a) to at least one compound of a transition metal of Group 4 to 6 and
c) obtaining the solid catalyst component particles,
and adding a non-phthalic internal electron donor (ID) at any step prior to step c).

11. The process according to claim 1 , wherein the propylene polymer composition (P) has a melting temperature in the range of 120° C. to 145° C.

12. The process according to claim 1 , wherein the propylene composition (P) has a MFR 2 in the range of 1 to 50 g/10 min.

Assignees

• Borealis Ag

Inventors

• Leskinen Pauli
• Wang Jingbo
• Lilja Johanna
• Gahleitner Markus

Classifications

• C08F4/6546

  organo-magnesium compounds · CPC title

• C08F110/06

  Propene · CPC title

• C08F210/06 Primary

  Propene · CPC title

• C08F4/6492

  containing aliphatic unsaturation · CPC title

• C08F210/08

  Butenes · CPC title