# US 10,308,731 B2 · Method for feeding an antistatic compound to a polymerization reactor

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- Number: US 10,308,731 B2
- Document ID: US10308731B2
- Status: Granted
- Kind: B2
- Application number: 13/876,719
- Filed: 2011-09-26
- Published: 2013-08-01
- Granted: 2019-06-04
- Earliest claimed: 2010-09-28
- Assignees: Basell Polyolefine GmbH
- Applicants: Pietro Baita; Paolo Ferrari; Ines Mingozzi; Lorella Pedriali; Maria Di Diego; Roberta Pica
- Inventors: Pietro Baita; Paolo Ferrari; Ines Mingozzi; Lorella Pedriali; Maria Di Diego; Roberta Pica
- Web page: https://patentgrep.com/patent/US10308731B2

## CPC

- C08F 4/16: of silicon, germanium, tin, lead, titanium, zirconium or hafnium
- C08F 10/00: Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F 110/02: Ethene
- C08F 210/16: Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
- C08F 2410/02: Anti-static agent incorporated into the catalyst
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS

## Abstract

A method for feeding an antistatic compound to a polymerization reactor comprising the steps of: a) dispersing, under mixing conditions, a catalyst powder and an antistatic compound in an oil, so as to form a suspension of catalyst powder and antistatic compound in said oil; b) successively adding, under mixing conditions, a molten thickening agent to said suspension from step a), while maintaining said suspension at a temperature such that said thickening agent solidifies on contact with said suspension; c) transferring the product obtained from b) to a polymerization reactor.

## Claims

### Claim 1

A method for feeding an antistatic compound to a polymerization reactor comprising:
a) dispersing, under mixing conditions, a catalyst powder and an antistatic compound comprising an ester in an oil, wherein the oil has a dynamic viscosity at 20° C. in a range of 10-250 centiPoise, to produce a suspension of the catalyst powder and of the antistatic compound in the oil;
b) successively adding, under mixing conditions, a molten thickening agent to the suspension of step a) wherein the feed temperature of the molten thickening agent in step b) ranges from 75-110° C. for obtaining a catalytic paste; and
c) transferring the catalytic paste of step b) or its separate components to a polymerization reactor;
wherein the catalytic paste, before entering the polymerization reactor, is optionally separated into its components by a flow of liquid alkane;
the thickening agent has a melting point in a range of 30-70° C.; and
the components of step a), the components of step b), oil and thickening agent cannot react,
wherein the oil comprises a mixture of hydrocarbons having a molecular weight distribution comprised between 100 and 1000, with an average molecular weight Mw ranging from 200 to 500 as measured at 150° C. and a flow rate of 1.0 mL/min as measured by gel permeation chromatography, and
wherein the weight ratio antistatic/catalyst is between 0.01 and 5.0.

### Claim 2 (depends on 1)

The method of claim 1, wherein the antistatic compound is incorporated in the suspension of step a) as a solid component.

### Claim 3 (depends on 1)

The method of claim 1, wherein step a) comprises the sequence of:
feeding an oil to a dispersion tank equipped with a stirring device;
loading said catalyst to said dispersion tank, while maintaining the dispersion tank under stirring conditions;
mixing the catalyst suspension for a time comprised between 30 and 150 minutes.

### Claim 4 (depends on 3)

The method of claim 3, wherein step a) comprises the sequence of:
after mixing the catalyst suspension for 30-90 minutes, cooling the catalyst suspension to a temperature ranging from 5 to 40° C.;
after the cooling step, adding said antistatic compound in the form of powder or microbeads to the catalyst suspension, while maintaining the suspension under stirring conditions;
subjecting the suspension to mixing conditions for a time comprised between 10 and 120 minutes.

### Claim 5 (depends on 1)

The method of claim 1, wherein in step a) the antistatic/catalyst weight ratio ranges from 0.10 to 3.0.

### Claim 6 (depends on 1)

The method of claim 1, wherein during the addition of said molten thickening agent in step b) the temperature of said suspension is kept at a value ranging from 10 to 30° C.

### Claim 7 (depends on 1)

The method of claim 1, wherein:
(i) the weight ratio (thickening agent)/oil is between 0.20 and 0.90; and
(ii) the weight ratio antistatic/catalyst is between 0.10 and 3.0.

### Claim 8 (depends on 1)

The method of claim 1, wherein the thickening agent is selected from the group consisting of petrolatum, greases and waxes.

### Claim 9 (depends on 1)

The method of claim 1, wherein the method includes the step of polymerizing at least one olefin in the presence of the catalyst paste.

### Claim 10 (depends on 9)

The method of claim 9, wherein the polymerization step includes polymerizing one or more α-olefins of formula CH2═CHR, where R is hydrogen or a hydrocarbon radical having from 1 to 12 carbon atoms, in one or more polymerization reactors in the presence of the catalytic paste.

### Claim 11 (depends on 3)

The method of claim 3, wherein the oil is fed to the dispersion tank at a temperature ranging from 5 to 40° C.

### Claim 12 (depends on 4)

The method of claim 4, wherein the oil is fed to the dispersion tank at a temperature ranging from 40 to 90° C.

### Claim 13 (depends on 1)

The method of claim 1, wherein the thickening agent is a mineral oil/wax blend.

### Claim 14 (depends on 1)

The method of claim 1, wherein the ester is selected from a hydroxyester and a polyglycerol ester.

### Claim 15 (depends on 14)

The method of claim 14, wherein the hydroxyester is selected from glycerol monostearate and glycerol monopalmitate.

### Claim 16 (depends on 14)

The method of claim 14, wherein the polyglycerol ester is diglycerol monooleate.