Control of a solution process for polymerization of ethylene

• US 5,589,555 A
• Filed: 07/07/1995
• Issued: 12/31/1996
• Est. Priority Date: 10/03/1991
• Status: Expired due to Fees

• Current Assignee: Novacor Chemicals (International SA (Nova Chemicals)
• Original Assignee: Novacor Chemicals (International SA (Nova Chemicals)
• Inventors: Brown, Stephen J., Zboril, Vaclav G.
• Primary Examiner(s): Delmendo, Romulo H.
• Application Number:
  US08/499,646
• Time in Patent Office: 543 Days
• Field of Search: 526/64, 526/65, 526/124.7, 526/124.9, 526/142, 526/153, 526/125.2, 526/116, 526/125.7
• US Class Current: 526/64
• CPC Class Codes: C08F 10/00 Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
• CPC Class Codes: C08F 10/02 Ethene
• CPC Class Codes: C08F 110/02 Ethene
• CPC Class Codes: C08F 2/06 Organic solvent
• CPC Class Codes: C08F 2400/02 Control or adjustment of polymerization parameters
• CPC Class Codes: C08F 2500/01 High molecular weight, e.g. >800,000 Da.
• CPC Class Codes: C08F 4/642 Component covered by group C08F4/64 with an organo-aluminium compound C08F4/64003 - C08F4/64196 take precedence
• CPC Class Codes: C08F 4/6546 organo-magnesium compounds
• CPC Class Codes: C08F 4/6555 and magnesium or compounds thereof
• CPC Class Codes: C08F 4/685 Vanadium or compounds thereof in combination with titanium or compounds thereof

Abstract

A solution process for the preparation of high molecular weight polymers of alpha-olefins selected from the group consisting of homopolymers of ethylene and copolymers of ethylene and C₃ -C₁₂ higher alpha-olefins is disclosed. Ethylene and/or mixtures of ethylene and C₃ -C₁₂ higher alpha-olefins are polymerized under non-isothermal conditions in a tubular reactor or in a system of reactors which operate under different conditions, in the presence of a catalytic amount of a titanium-containing coordination catalyst in an inert solvent at a temperature in excess of 105° C. The improvement is characterized in that:

(a) the catalyst is activated with a solution of a mixture of aluminum alkyl and alkoxy aluminum alkyl in inert solvent; and

(b) the process is controlled by adjusting the ratio of aluminum alkyl to alkoxy aluminum alkyl in the mixture of (a). The aluminum alkyl is of the formula AlR_n X_3-n and the alkoxy aluminum alkyl is of the formula AlR'"'"'_m OR"_3-m, in which each of R, R'"'"' and R" is alkyl or aryl of 1-20 carbon atoms, X is halogen, n is 2-3 and m is 0-3.

Claims

1. A process for the solution polymerization of high molecular weight polymers of alpha olefins selected from the group consisting of homopolymers of ethylene and copolymers of ethylene and C_3-12 alpha olefins at a temperature from 105°

to 320°

C. and a pressure from 4-20 MPa, said process comprising feeding to a tubular reactor kept under non-isothermal conditions or a series of reactors which operate under different conditions, monomer, selected from the group consisting of ethylene and mixtures of ethylene and at least one C_3-12 alpha olefin, a hydrocarbon solvent and a catalyst;

wherein said catalyst is prepared by in-line mixing at a temperature of less than 30°

C.;

(i) a catalyst precursor prepared by the in-line mixing at a temperature of less than 30°

C. of a mixture consisting of;

(a) MgR¹₂ and AIR²₃ wherein each R¹ and R² is the same or different and is a C_1-10 alkyl radical;

(b) a reactive halide; and

(c) titanium tetrachloride;

to provide a molar ratio of halide to magnesium from 2.2 to 2.4;

magnesium to titanium of 5; and

aluminum to titanium of 0.9;

with

(ii) a catalyst activator prepared by in-line mixing at a temperature of less than 30°

C. a composition consisting of;

(d) a first component which is an aluminum alkyl of the formula AIR₃ wherein R is an alkyl radical of the 2-8 carbon atoms;

with

(e) an alcohol of the formula R⁴ OH wherein R⁴ is a C_1-20 alkyl radical in a ratio of alcohol to aluminum from 0.1 to 1.