PROCESS FOR THE PREPARING HETEROPHASIC PROPYLENE COPOLYMERS

• US 20200131284A1
• Filed: 06/14/2018
• Published: 04/30/2020
• Est. Priority Date: 07/07/2017
• Status: Active Grant

• Current Assignee: Borealis AG (Government of ABU Dhabi)
• Original Assignee: Borealis AG (Government of ABU Dhabi)
• Inventors: Resconi, Luigi Maria Cristoforo, Toltsch, Wilfried, Virkkunen, Ville, Lehtiniemi, Ismo, Ajellal, Noureddine
• Granted Patent: US 11,078,304 B2
• Time in Patent Office: Days
• CPC Class Codes: C08F 2/001 Multistage polymerisation processes characterised by a change in reactor conditions without deactivating the intermediate polymer C08F295/00, C08F297/00 take precedence
• CPC Class Codes: C08F 2/01 characterised by special features of the polymerisation apparatus used
• CPC Class Codes: C08F 2/34 Polymerisation in gaseous state
• CPC Class Codes: C08F 210/06 Propene
• CPC Class Codes: C08F 210/16 Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
• CPC Class Codes: C08F 2500/17 Viscosity
• CPC Class Codes: C08F 4/65912 in combination with an organoaluminium compound
• CPC Class Codes: C08F 4/65927 two cyclopentadienyl rings being mutually bridged
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 2207/02 Heterophasic composition
• CPC Class Codes: C08L 23/12 Polypropene
• CPC Class Codes: C08L 23/16 Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
• CPC Class Codes: C08L 2314/06 Metallocene or single site catalysts

Abstract

Process for producing a heterophasic propylene copolymer using a specific class of metallocene complexes in a multistage polymerization process including a gas phase polymerization step. The invention further relates to the use of catalysts which comprise a specific class of metallocene complexes to produce a heterophasic propylene copolymer in a multistep process including a gas phase polymerization step.

Claims

1. :

A process for the preparation of a heterophasic propylene copolymer, the process comprising;

preparing the heterophasic propylene copolymer in the presence of a single site catalyst comprising;

(i) a complex of formula (I);

2. The process as claimed in claim 1, wherein in the formula (I) each X is independently a hydrogen atom, a halogen atom, C_1-6 alkoxy group, C_1-6 alkyl, phenyl or benzyl group.

3. :

The process according to claim 1, wherein in the formula (I) L is dimethylsilyl, methylcyclohexylsilyl (i.e. Me-Si-cyclohexyl), ethylene or methylene.

4. :

The process according to claim 1, wherein in the formula (I);

R³ and R^3′

are the same and are linear C₁ to C₄ alkyl group, and

R⁴ and R^4′

are each independently a branched C₄ to C₆ alkyl group.

5. :

The process according to claim 1, wherein in the formula (I);

M is zirconium,

X is independently a halogen atom, C_1-4 alkoxy group, C_1-4 alkyl, phenyl or benzyl group,

L is dimethylsilyl,

R¹ and R^1′

are the same and are hydrogen or a group —

CH₂R^x wherein R^x is either H or a C_1-3 alkyl group,

R² and R^2′

are the same and are hydrogen or a group —

CH₂R^x wherein R^x is either H or a C_1-3 alkyl group,

whereby either R¹ and R^1′

or R² and R^2′

are hydrogen,

R³ and R^3′

are the same and are a linear C₁ to C₄ group,

R⁴ and R^4′

are each a tert.-butyl group, and

R⁵ and R^5′

are each a linear C₁ to C₄ alkyl group.

6. :

The process according to claim 1, wherein the complex of formula (I) is rac-Me₂Si(2-Me-4-(3,5-Me₂Ph)-5-OMe-6-tBu-Ind)₂ZrCl₂ or rac-Me₂Si(2-Me-4-(4-tBu-Ph)-5-OMe-6-tBu-Ind)₂ZrCl₂

7. :

The process according to claim 1, wherein the cocatalyst is an aluminoxane cocatalyst.

8. :

The process as claimed in claim 7, wherein in the formula (I) X is Zr and the ratio of Al/Zr is from 150 up to 1000 mol/mol.

9. :

The process according to claim 1, wherein the catalyst used is in solid particulate form free from an external carrier.

10. :

The process as claimed in claim 9, wherein the catalyst is prepared by forming a liquid/liquid emulsion system, which comprises a solution of catalyst components (i) and (ii) dispersed in a solvent, and solidifying said dispersed droplets to form solid particles.

11. :

The process according to claim 1, wherein the heterophasic copolymer is produced in a multistage process comprising at least two reactors connected in series including at least one gas phase polymerization step.

12. :

The process according to claim 1, wherein the heterophasic copolymer comprises;

(a-1) a matrix (M) being a polypropylene homo- or ethylene copolymer, and

(a-2) and elastomeric propylene-ethylene copolymer (E) dispersed in said matrix (M),

wherein the elastomeric propylene-ethylene copolymer (E) has;

(i) an intrinsic viscosity (iV) determined according to DIN ISO 1628/1 (in decalin at 135°

C.) in the range of from 3.1 to 8.0 dl/g,

(ii) an ethylene comonomer content in the range of from 10.0 to 80.0 wt %,

(iii) optionally a second comonomer selected from 1-butene in an amount of from 0.0 up to 20.0 wt % or 1-hexene in an amount of from 0.0 up to 10.0 wt %, and

(iv) a xylene soluble (XS) fraction (determined according to ISO 16152 at 25°

C.) of at least 50.0 wt %, and

wherein the xylene soluble (XS) fraction (determined according to ISO 16152 at 25°

C.) of the heterophasic propylene copolymer is in the range of from 5.0 to 50.0 wt %.

3-1. :

The process according to claim 12, wherein the matrix (M) of the heterophasic polypropylene copolymer is a polypropylene homopolymer with a molecular weight distribution (MWD;

M_w/M_n as measured with GPC) is in a range of from 2.5 to 7.0.

14. :

The process as claimed in claim 12 comprising;

(A) polymerizing propylene and optionally ethylene in at least a first reactor and optionally a second reactor to form a propylene homopolymer component or propylene-ethylene random copolymer component, said homopolymer or copolymer component forming the matrix (M), and

(B) polymerizing propylene and ethylene in a gas phase reactor in the presence of the polymer prepared in step (A) so as to form a elastomeric propylene-ethylene copolymer component (E).

15. :

The process according to claim 14, wherein;

(a) in a first reactor propylene and optionally ethylene are polymerized obtaining a first propylene homo- or copolymer fraction (R-PP1),

(b) transferring said first propylene homo- or copolymer fraction (R-PP1) in a second reactor,

(c) polymerizing in said second reactor in the presence of the first propylene homo- or copolymer fraction (R-PP1) propylene and optionally ethylene obtaining a second propylene homo- or copolymer fraction (R-PP2), said first propylene homo- or copolymer fraction (R-PP1) and said second propylene homo- or copolymer fraction (R-PP2) form the matrix (M),

(d) transferring said matrix (M) into a third reactor, said third reactor being a gas phase reactor,

(e) polymerizing in said third reactor in the presence of the matrix (M) propylene, and

ethylene obtaining an elastomeric propylene copolymer (E), said matrix (M) and said elastomeric propylene copolymer (E) form the heterophasic propylene copolymer.

16. (canceled)