Polymer composition with high XS, high Tm suitable for BOPP processing

Patent metadata

Field	Value
Publication number	US-10040930-B2
Application number	US-201415022664-A
Country	US
Kind code	B2
Filing date	Sep 23, 2014
Priority date	Sep 27, 2013
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

Polypropylene copolymer for biaxially oriented polypropylene (BOPP) with low isotacticity, high melting temperature and low comonomer content.

First claim

The invention claimed is:

1. A polypropylene copolymer (R-PP) having
(a) a comonomer content in the range from 0.1 to 3.0 mol-% based on the weight of the polypropylene copolymer (R-PP), wherein the comonomer is ethylene,
(b) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range from 1.0 to 10.0 g/10min,
(c) a melting temperature T m of more than 150.0° C. and
(d) an isotacticity of not more than 92.0%,
(e) a xylene cold soluble fraction (XCS) in the range from 4.0 to 10.0 wt.-%.

2. The polypropylene copolymer (R-PP) according to claim 1 , wherein the polypropylene copolymer (R-PP) has
(a) a Vicat A softening point of below 154.0° C. and/or
(b) a molecular weight distribution (MWD) in the range of 3.0 to 10.0.

3. The polypropylene copolymer (R-PP) according to claim 1 , wherein said polypropylene copolymer (R-PP) comprises two fractions, a first propylene homopolymer fraction (R-PP1) and a second propylene copolymer fraction (R-PP2), wherein said first propylene homopolymer fraction (R-PP1) differs from said second propylene copolymer fraction (R-PP2) in the melt flow rate.

4. The polypropylene copolymer (R-PP) according to claim 3 , wherein
(a) the first propylene homopolymer fraction (R-PP1) and the second propylene copolymer fraction (R-PP2) fulfill together the inequation (Ia),

MFR
⁡

(

R
-

PP
⁢

⁢
1

)

MFR
⁡

(

R
-

PP
⁢

⁢
2

)

≥
1.5

(
Ia
)

wherein
MFR (R-PP1) is the melt flow rate MFR 2 (230° C.) [g/10min] of the first propylene homopolymer fraction (R-PP1) and
MFR (R-PP2) is the melt flow rate MFR 2 (230° C.) [g/10min] of the second propylene copolymer fraction (R-PP2)
and/or
(b) the polypropylene copolymer (R-PP) and the second propylene copolymer fraction (R-PP2) fulfill together the inequation (IIa)

MFR
⁡

(

R
-

PP
⁢

⁢
1

)

MFR
⁡

(

R
-
PP

)

≥
1.3

(
IIa
)

wherein
MFR (R-PP) is the melt flow rate MFR 2 (230° C.) [g/10min] of the polypropylene copolymer (R-PP) and
MFR (R-PP1) is the melt flow rate MFR 2 (230° C.) [g/10min] of the first propylene homopolymer fraction (R-PP1).

5. The polypropylene copolymer (R-PP) according to claim 3 , wherein the second propylene copolymer fraction (R-PP2) has a comonomer content in the range from more than 0.1 to 6.0 mol-%.

6. The polypropylene copolymer (R-PP) according to claim 3 , wherein the first propylene homopolymer fraction (R-PP1) has a higher melt flow rate than the second propylene copolymer fraction (R-PP2).

7. A process for preparing a polypropylene copolymer (R-PP) according to claim 3 , comprising a first propylene homopolymer fraction (R-PP1) and a second propylene copolymer fraction (R-PP2), wherein said process is 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)
(a1) propylene obtaining thereby said first propylene homopolymer fraction (R-PP1),

(b) transferring said first propylene homopolymer fraction (R-PP1) and unreacted monomers from the first reactor (R-1) into a second reactor (R-2),
(c) feeding to said second reactor (R-2)
(c1) propylene and
(c2) ethylene,

(d) polymerizing in said second reactor (R-2) and in the presence of said first propylene homopolymer fraction (R-PP1)
(d1) propylene and
(d2) ethylene,

obtaining said polypropylene copolymer (R-PP) comprising the first propylene homopolymer fraction (R-PP1) and the second propylene copolymer fraction (R-PP2),
wherein the polymerization takes place in the presence of a solid catalyst system (SCS), said solid catalyst system (SCS) comprises
(i) a transition metal (TM) selected from one of the groups 4 to 6 of the periodic table (IUPAC),
(ii) a metal which is selected from one of the groups 1 to 3 of the periodic table (IUPAC),
(iii) an internal electron donor (ID)
(iv) a cocatalyst (Co), and
(v) an external donor (ED).

8. The process according to claim 7 , wherein the solid catalyst system (SCS) comprises a cocatalyst (Co) and a transition metal (TM) in the molar ratio [(Co)/(TM)] above 95.

9. The process according to claim 7 , wherein the solid catalyst system (SCS) comprises a cocatalyst (Co) and a an external donor (ED) in the molar ratio [(Co)/(ED)] above 50.

10. The process according to claim 7 , wherein the solid catalyst system (SCS) comprises an external donor (ED) and a transition metal (TM) in the molar ratio [(ED)/(TM)] below 10.

11. A biaxially oriented polymer film comprising a polypropylene copolymer (R-PP) according to claim 1 .

12. A process for preparing a biaxially oriented polypropylene (BOPP) according to claim

Assignees

• Borealis Ag
• Abu Dhabi Polymers Co Ltd Borouge Llc

Inventors

• Gloger Dietrich
• Horill Thomas
• Francis Vijay
• Sakkaraiyappan Gurusamy
• Dixit Niraj
• Alastalo Kauno
• Vestberg Torvald
• Defoer Johan

Classifications

• C08J2323/16

  Ethene-propene or ethene-propene-diene copolymers · CPC title

• C08F210/06

  Propene · CPC title

• C08L2205/02

  containing two or more polymers of the same C08L -group · CPC title

• C08L2308/00

  Chemical blending or stepwise polymerisation process with the same catalyst · CPC title

• C08L23/12 Primary

  Polypropene · CPC title