# US 12,110,359 B2 · Continuous process for metallocene preliminary polymerization for gas-phase polymerization process

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- Number: US 12,110,359 B2
- Document ID: US12110359B2
- Status: Granted
- Kind: B2
- Application number: 17/866,410
- Filed: 2022-07-15
- Published: 2023-02-02
- Granted: 2024-10-08
- Earliest claimed: 2021-07-15
- Assignees: Braskem S.A.
- Applicants: Braskem S.A.
- Inventors: Olavo Martins Junior; Fabio Andre Kunrath; Márcia Silva Lacerda Miranda
- Web page: https://patentgrep.com/patent/US12110359B2

## CPC

- C08F 4/14: Boron halides or aluminium halides; Complexes thereof with organic compounds containing oxygen
- C08F 4/65916: {supported on a carrier, e.g. silica, MgCl2, polymer}
- C08F 210/02: Ethene
- C08F 210/16: Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
- C08F 4/65912: {in combination with an organoaluminium compound}
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS

## Abstract

A process for preliminary polymerization may include washing a catalyst mud comprising a supported metallocene catalyst with at least one saturated hydrocarbon at a temperature from 0° C. to 40° C., a pressure from 20 to 40 kgf/cm2, and a residence time of at least 30 minutes; continuously feeding the washed catalytic mud to a continuous pre-polymerization reactor; and pre-polymerizing, in the continuous pre-polymerization reactor, ethylene and at least one C4 to C10 α-olefin as comonomer, with the washed catalytic mud, to produce a pre-polymer; wherein an average residence time in the continuous pre-polymerization reactor is more than 90 minutes and less than 240 minutes, a reactor temperature is from 10° C. to 50° C., and a reactor pressure from 20 to 40 kgf/cm2.

## Claims

### Claim 1

A process for preliminary polymerization, comprising:
washing a catalyst mud comprising a supported metallocene catalyst with a solvent at a temperature from 0° C. to 40° C., a pressure from 20 to 40 kgf/cm2, and a residence time of at least 30 minutes;
continuously feeding the washed catalytic mud to a continuous pre-polymerization reactor; and
pre-polymerizing, in the continuous pre-polymerization reactor, ethylene and at least one C4 to C10 α-olefin as comonomer, with the washed catalytic mud, in the presence of an inert diluent, to produce a pre-polymer.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the catalyst mud comprises the supported metallocene catalyst mixed with mineral oil, grease, wax, or paraffin, or a combination thereof.

### Claim 3 (depends on 1)

The process according to claim 1, wherein the solvent comprises a saturated hydrocarbon selected from the group consisting of propane, butane, iso-butane, pentane, iso-pentane, hexane, heptane and combinations thereof.

### Claim 4 (depends on 1)

The process according to claim 1, wherein the inert diluent is selected from the group consisting of C3-C7 alkanes and combinations thereof.

### Claim 5 (depends on 1)

The process according to claim 1, wherein the continuous pre-polymerization reactor is a tubular reactor, a continuous stirred tank reactor (CSTR), or a loop reactor.

### Claim 6 (depends on 1)

The process according to claim 1, wherein an amount of hydrogen ranging from 0 to 0.05 gram of hydrogen per kilogram of ethylene is present in the continuous pre-polymerization reactor.

### Claim 7 (depends on 1)

The process according to claim 1, wherein the supported metallocene catalyst, after washing, has:
a d50 ranging from 35 to 70 μm;
a d10 ranging from 14 to 40 μm;
a total intrusion volume less than or equal to 1 mL/g; and
a total pore area less than or equal to 100 m2/g.

### Claim 8 (depends on 1)

The process according to claim 1, wherein washing the catalytic mud uses from 1 to 10 kg of solvent per gram of the supported metallocene catalyst.

### Claim 9 (depends on 1)

The process according to claim 1, wherein an ethylene/supported metallocene catalyst mass ratio fed into the continuous pre-polymerization reactor is in the range of 5 to 150; and a comonomer/ethylene mass ratio fed into the continuous pre-polymerization reactor is in the range of 0.1 to 1.2.

### Claim 10 (depends on 1)

The process according to claim 1, wherein a polymerization degree of the pre-polymerized polymer is less than 60 g of polymer per gram of supported metallocene catalyst.

### Claim 11 (depends on 1)

The process according to claim 1, further comprising continuously feeding the pre-polymerized polymer to a polymerization reactor.

### Claim 12 (depends on 11)

The process according to claim 11, wherein the polymerization reactor is a gas phase reactor.

### Claim 13 (depends on 11)

The process according to claim 11, wherein an amount of unreacted comonomer transferred from the continuous pre-polymerization reactor to the polymerization reactor is no more than 10 wt % of the total amount of comonomer continuously fed into the polymerization reactor.

### Claim 14 (depends on 1)

The process according to claim 1, wherein the preliminary polymerization is carried out in presence of an antistatic agent in the range of 1 to 10 wppm based on the total amount of monomer, comonomer, and inert diluent present in the pre-polymerization reactor.

### Claim 15 (depends on 1)

The process according to claim 1,
wherein an average residence time in the continuous pre-polymerization reactor is more than 90 minutes and less than 240 minutes, a reactor temperature is from 10° C. to 50° C., and a reactor pressure is from 20 to 40 kgf/cm2.