Propylene copolymer composition with excellent optical and mechanical properties

Patent metadata

Field	Value
Publication number	US-2022135779-A1
Application number	US-201917273687-A
Country	US
Kind code	A1
Filing date	Aug 7, 2019
Priority date	Sep 26, 2018
Publication date	May 5, 2022
Grant date	—

Abstract

The present invention is directed to a polypropylene composition (P) comprising a copolymer (C) of propylene and 1-hexene comprising a first random propylene copolymer (A) of propylene and a 1-hexene, and a second random propylene copolymer (B) of propylene and 1-hexene having a higher 1-hexene content than the first random propylene copolymer (A) as well as a plastomer (PL) being an elastomeric copolymer of ethylene and at least one C4 to C10 α-olefin. Further, the present invention is directed to an article comprising said polypropylene composition (P) and the use of said polypropylene composition (P) as a sealing layer in a multi-layer film.

First claim

1 - 16 . (canceled)

17 . A polypropylene composition (P), comprising
a) 80.0 to 99.0 wt. %, based on the overall weight of the polypropylene composition (P), of a copolymer (C) of propylene and 1-hexene, comprising
i) a first random propylene copolymer (A) of propylene and a 1-hexene, and
ii) a second random propylene copolymer (B) of propylene and 1-hexene having a higher 1-hexene content than the first random propylene copolymer (A),
wherein the copolymer (C) has a xylene soluble content (XCS) of at least 8.0 wt. %, and
b) 1.0 to 20.0 wt. %, based on the overall weight of the polypropylene composition (P), of a plastomer (PL) which is an elastomeric copolymer of ethylene and at least one C 4 to C 10 α-olefin having a density in the range of 0.860 to 0.930 g/cm 3 .

18 . The polypropylene composition (P) according to claim 17 , wherein the copolymer (C) has an amount of 2,1 erythro regio-defects of at least 0.4 mol. %.

19 . The polypropylene composition (P) according to claim 17 , wherein the copolymer (C) has a melt flow rate MFR 2 (230° C., 2.16 kg) determined according to ISO 1133 in the range of 0.4 to 12.0 g/10 min.

20 . The polypropylene composition (P) according to claim 17 , wherein the weight ratio between the first random propylene copolymer (A) and the second random propylene copolymer (B) within the copolymer (C) is in the range of 30:70 to 70:30.

21 . The polypropylene composition (P) according to claim 17 , wherein the copolymer (C) fulfils in-equation (1)
MFR( C )/MFR( A )≤1.0  (1),
wherein MFR(A) is the melt flow rate MFR 2 (230° C., 2.16 kg) determined according to ISO 1133 in [g/10 min] of the first random propylene copolymer (A) and MFR(C) is the melt flow rate MFR 2 (230° C., 2.16 kg) determined according to ISO 1133 in [g/10 min] of the copolymer (C).

22 . The polypropylene composition (P) according to claim 17 , wherein the copolymer (C) has a 1-hexene content of the xylene soluble fraction C6 (XCS) in the range of 2.0 to 8.0 wt. %.

23 . The polypropylene composition (P) according to claim 17 , wherein
i) the first random propylene copolymer (A) has a melt flow rate MFR 2 (230° C., 2.16 kg) determined according to ISO 1133 in the range of 0.3 to 12.0 g/10 min, and/or ii) the second random propylene copolymer (B) has a melt flow rate MFR 2 (230° C., 2.16 kg) determined according to ISO 1133 in the range of 0.1 to 14.0 g/10 min.

24 . The polypropylene composition (P) according to claim 17 , wherein the copolymer (C) fulfils in-equation (2)

4
.
5

≤

C
⁢
6
⁢

(
C
)

C
⁢
6
⁢

(
A
)

*

[
A
]

[
C
]

≤

9
.
0

(
2
)

wherein
C6(A) is the 1-hexene content of the first random propylene copolymer (A) based on the total weight of the first random propylene copolymer (A) [in wt. %];
C6(C) is the 1-hexene content of the copolymer (C) based on the total weight of the copolymer (C) [in wt. %]; and
[A]/[C] is the weight ratio between the first random propylene copolymer (A) and the copolymer (C) [in g/g].

25 . The polypropylene composition (P) according to claim 17 , wherein the plastomer (PL) has a density in the range of 0.865 to 0.920 g/cm 3 .

26 . The polypropylene composition (P) according to claim 17 , wherein the plastomer (PL) is a copolymer of ethylene and 1-octene.

27 . An article comprising at least 90.0 wt. % of the polypropylene composition (P) according to claim 17 .

28 . The article according to claim 27 , wherein the article is a film.

29 . The article according to claim 28 , wherein the film has
i) a haze before steam sterilization determined according to ASTM D 1003-00 measured on a 50 μm blown film below 10.0%, and ii) a haze after steam sterilization determined according to ASTM D 1003-00 measured on a 50 μm blown film below 12.0%.

30 . A sealing layer in a multi-layer film, the sealing layer comprising a film comprising at least 90.0 wt. % of the polypropylene composition (P) according to claim 17 .

31 . A process for the preparation of the polypropylene composition (P) according to claim 17 , wherein the process is a sequential polymerization process comprising at least two reactors connected in series, wherein said process comprises:
(A) polymerizing in a first reactor (R-1) being a slurry reactor (SR), propylene and 1-hexene, obtaining a first random propylene copolymer (A), (B) transferring said first random propylene copolymer (A) and unreacted comonomers of the first reactor (R-1) in a second reactor (R-2) which is a gas phase reactor (GPR-1), (C) feeding to said second reactor (R-2) propylene and 1-hexene, (D) polymerizing in said second reactor (R-2) and in the presence of said first random propylene copolymer (A) propylene and 1-hexene obtaining a second random propylene copolymer (B), said first random propylene copolymer (A) and said second random propylene copolymer (B) form the copolymer (C), and (E) blending the copolymer (C) with the plastomer (PL) and obtaining the polypropylene composition (P), wherein further in the first reactor (R-1) and second reactor (R-2), the polymerization takes place in the presence of a solid catalyst system (SCS), said solid catalyst system (SCS) comprising a transition metal compound of formula (I)
R n (Cp) 2 MX 2   (I)

wherein: each Cp independently is an unsubstituted or substituted and/or fused cyclopentadienyl ligand, substituted or unsubstituted indenyl or substituted or unsubstituted fluorenyl ligand, wherein the optional one or more substituent(s) is/are independently selected from the group consisting of halogen, C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl, C 2 -C 20 -alkynyl, C 3 -C 12 -cycloalkyl, C 6 -C 20 -aryl, C 7 -C 20 -arylalkyl, C 3 -C 12 -cycloalkyl which contains 1, 2, 3 or 4 heteroatom(s) in the ring moiety, C 6 -C 20 -heteroaryl, C 1 -C 20 -haloalkyl, —SiR″ 3 , —OSiR″ 3 , —SR″, —PR″ 2 , —OR″, and —NR″ 2 , wherein each R″ is independently a hydrogen or a hydrocarbyl selected from the group consisting of C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl, C 2 -C 20 -alkynyl, C 3 -

Assignees

• Borealis Ag

Inventors

• Wang Jingbo
• Gahleitner Markus
• Bernreitner Klaus
• Niedersüss Peter
• Leskinen Pauli

Classifications

• C08L2205/03

  containing three or more polymers in a blend · CPC title

• C08F2/00

  Processes of polymerisation · CPC title

• B29C48/08

  flexible, e.g. films · CPC title

• C08F210/06

  Propene · CPC title

• C08L23/14 Primary

  Copolymers of propene (C08L23/16 takes precedence) · CPC title