Process for the preparation of high purity propylene polymers

• US 10,221,261 B2
• Filed: 09/17/2012
• Issued: 03/05/2019
• Est. Priority Date: 09/23/2011
• Status: Active Grant

• Current Assignee: Basell Poliolefine Italia Srl (Lyondellbasell Industries NV)
• Original Assignee: Basell Poliolefine Italia Srl (Lyondellbasell Industries NV)
• Inventors: Galvan, Monica, Pantaleoni, Roberto, Fusco, Ofelia, Gaddi, Benedetta, Neumann, Andreas, Mazzucco, Antonio, Collina, Gianni, Sartori, Gabriella
• Primary Examiner(s): Lee, Rip A
• Application Number:
  US14/346,648
• Publication Number:
  US 20140235802A1
• Time in Patent Office: 2,360 Days
• Field of Search: 526351
• CPC Class Codes: B01J 31/0204 Ethers
• CPC Class Codes: B01J 31/0209 Esters of carboxylic or carbonic acids
• CPC Class Codes: C08F 10/06 Propene
• CPC Class Codes: C08F 110/06 Propene
• CPC Class Codes: C08F 2500/04 Broad molecular weight distribution, i.e. Mw/Mn > 6
• CPC Class Codes: C08F 2500/12 Melt flow index or melt flow ratio
• CPC Class Codes: C08F 2500/15 Isotactic
• CPC Class Codes: C08F 4/651 Pretreating with non-metals or metal-free compounds
• CPC Class Codes: C08F 4/6543 halides of magnesium
• CPC Class Codes: C08J 2323/14 Copolymers of propene C08J2323/16 takes precedence
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets

Abstract

A process for the preparation of high purity propylene polymers carried out in the presence of a catalyst comprising the product obtained by contacting:

(a) a solid catalyst component comprising Mg, Ti and at least a first internal electron donor compound (1ID) selected among the succinates and a second internal electron donor compound (2ID) selected among the 1,3-diethers, wherein the molar ratio of first internal donor over second internal donor 1ID:2ID is comprised between 4:6 and 9:1, with
(b) an organo-aluminum compound, and optionally with
(c) an external electron donor compound,
said process being carried out at a temperature equal or higher than 78° C. and by employing a molar ratio of organo-aluminum compound over solid catalyst component (b):(a) of lower than 5.

Claims

1. A low ash process for the preparation of a high purity propylene copolymer comprising copolymerizing propylene in the presence of a catalyst system comprising:

(a) a solid catalyst component comprising Mg, Ti, a first internal electron donor compound (1ID) comprising a succinate and a second internal electron donor compound (2ID) comprising a 1,3-diether, wherein the molar ratio of the first internal donor compound and the second internal donor compound 1ID;

2ID is from 4;

6-9;

1 and the solid catalyst component comprising an average particle size of 25-65 μ

m; and

(b) an organo-aluminum compound;

wherein the process is carried out at a temperature equal to or higher than 78°

C. with a weight ratio of organo-aluminum compound to propylene from 0.005-0.020 kg/ton, and wherein the propylene copolymer comprises an M_w/M_n greater than 6.0, a rheological polydispersity index (PI) greater than 3.5, an isotacticity greater than 98.0%, a Mg content lower than 2 ppm, a Cl content lower than 5 ppm, a Ti content lower than 1 ppm, and an Al content lower than 3 ppm.

2. The process according to claim 1, wherein the succinate for use as internal electron donor compound 1ID is selected from those belonging to the following formula (I):

3. The process according to claim 1, wherein the 1,3-diether for use as internal electron donor compound 2ID is selected from those belonging to the following formula (II):

4. The process according to claim 1, wherein the organo-aluminum compound (b) is selected from trialkyl aluminum compounds.

5. The process according to claim 1, wherein a weight ratio of organo-aluminum compound to solid catalyst component (b):

(a) is lower than 5.0.

6. The process of claim 1, further comprising contacting the solid catalyst component with an external electron donor compound.

7. The process according to claim 6, wherein the external electron donor compound (c) is selected among the silicon compounds of formula R_a⁵R_b⁶Si(OR⁷)_c, wherein a and b are integer from 0 to 2, c is an integer from 1 to 3 and the sum (a+b+c) is 4;

R⁵, R⁶, and R⁷, are alkyl, cycloalkyl or aryl radicals with 1-18 carbon atoms optionally containing heteroatoms.

8. The process according to claim 1, wherein the propylene copolymer comprises an ash content lower than 40 ppm.

9. The process of claim 1, wherein the propylene copolymer comprises an M_w/M_n greater than 6.5.

10. The process of claim 1, wherein the propylene copolymer comprises a rheological polydispersity index (PI) greater than 4.

11. The process according to claim 1, wherein the process includes a step of forming a film comprising the high purity propylene copolymer.