Copolymerization of ethylene and an alpha-olefin having six carbon atoms comprising hexene-1 or 4-methyl-pentene-1 in a fluidized bed

• US 4,987,212 A
• Filed: 11/03/1987
• Issued: 01/22/1991
• Est. Priority Date: 09/07/1982
• Status: Expired due to Term

• Current Assignee: BP Chimie Societe Anonyme
• Original Assignee: BP Chimie Societe Anonyme
• Inventors: Morterol, Frederic, Vidal, Jean-Louis
• Primary Examiner(s): Michl, Paul R.
• Assistant Examiner(s): Wright, Lee C.
• Application Number:
  US07/117,400
• Time in Patent Office: 1,176 Days
• Field of Search: 526/348.4
• US Class Current: 526/348.4
• CPC Class Codes: C08F 2/34 Polymerisation in gaseous state
• CPC Class Codes: C08F 210/14 Monomers containing five or more carbon atoms
• CPC Class Codes: C08F 210/16 Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
• CPC Class Codes: C08F 2410/06 Catalyst characterized by its size
• CPC Class Codes: C08F 2500/03 Narrow molecular weight distribution, i.e. Mw/Mn < 3
• CPC Class Codes: C08F 2500/09 Long chain branches
• CPC Class Codes: C08F 4/6355 and magnesium or compounds thereof
• CPC Class Codes: Y10S 526/901 Monomer polymerized in vapor state in presence of transition metal containing catalyst
• CPC Class Codes: Y10S 526/903 Monomer polymerized in presence of transition metal containing catalyst and hydrocarbon additive affecting polymer properties of catalyst activity
• CPC Class Codes: Y10S 526/904 Monomer polymerized in presence of transition metal containing catalyst at least part of which is supported on a polymer, e.g. prepolymerized catalysts

Abstract

Process for the preparation of copolymers of ethylene and an alpha-olefin having six carbon atoms comprising hexene-1 or 4-methyl-pentene-1 with a density comprised between 0.910 and 0.940, involving a copolymerization of ethylene and an alpha-olefin having six carbon atoms comprising hexene-1 or 4-methyl-pentene-1 in the gas phase by means of a fluidized bed, in the presence of a catalyst system comprising on the one hand a co-catalyst consisting of at least one organo-metallic compound of a metal of Groups, II and III of the Periodic Table of Elements and on the other hand a supported catalyst comprising a special support based essentially on magnesium chloride and optionally aluminum chloride, on which support there has been precipitated a derivative of a transition metal of Groups IV, V and VI of the Periodic Table of Elements.

Claims

1. A co-polymer of ethylene and 4-methyl-pentene-1, characterised in that it is the form of a powder consisting of non-sticky particles having a mean diameter by mass, Dm, comprised between 300 and 1500 microns, and a particle size distribution such that the ratio Dm:

Dn is less than or equal to 3.5, and characterised in that it has;

(a) a content of units derived from 4-methyl-pentene-1 comprised between 4 and 15% by weight,

(b) a density comprised between 0.910 and 0.940,

(c) a bulk density comprised between 0.35 and 0.45 g/cm³,

(d) an unsaturation level of less than 0.2 double bonds per 1000 carbon atoms,

(e) a single melting point comprised between 116° and

128°

C., determined by scanning differential calorimetric analysis after re-heating to 200°

C., cooling at the rate of 16°

C. per minute and heating at the rate of 16°

C. per minute,

(f) a structure with a small amount of long-chain branches such that g* is greater than or equal to 0.90 wherein g* is the ratio η

/η

₁, η

being the intrinsic viscosity of the copolymer and η

₁ being the intrinsic viscosity of a liner polyethylene having the same weight average molecular weight as the said copolymer, and is obtained by a co-polymerisation process comprising providing a catalyst system comprising on the one hand a co-catalyst consisting of at least one organo-metallic compound of a metal of Groups II and III of the Periodic Table of Elements and on the other hand a catalyst comprising a support based essentially on magnesium chloride and optionally containing an aluminium chloride, consisting of particles of spheroidal shape having a mean diameter by mass comprised between 10 and 100 microns and showing a particle size distribution such that the ratio Dm/Dn of the mean diameter by mass, Dm, to the mean diameter by number, Dn, of the particles is less than or equal to 3, on to which support there has been precipitated a derivative of a transition metal of Groups IV, V and VI of the Periodic Table of Elements which is known for its catalytic properties in the polymerisation and co-polymerisation of alpha-olefins,

wherein before the said co-polymerisation is carried out, subjecting the catalyst to a pre-polymerisation of the ethylene or a pre-co-polymerisation of the ethylene and 4-methyl-pentene-1 in suspension in an inert liquid medium so as to obtain a prepolymer having from 0.1 to 500 g. of polymer or co-polymer per milli-gramme-atom of transition metal,

recovering said prepolymer as a dry powder,

co-polymerising ethylene and said 4-methyl-pentene-1 in the gaseous state in admixture with said prepolymer powder, an inert gas such as nitrogen, methane or ethane and optionally with hydrogen, the gaseous mixture circulating from bottom to top through a fluidised bed of the co-polymer being formed, the co-polymerisation being effected at a temperature comprised between 50° and

90°

C., in the presence of said catalyst, and

the partial pressure (pp) of the various constituents of the gaseous mixture being such that;

pp 4-methyl-pentene-1 is in the range 0.05 MPa to 0.15 MPa, pp 4-methyl-pentene-1/pp ethylene is in the range 0.15 to 0.5, pp hydrogen/pp ethylene is in the range 0.05 to 0.5, pp inert gas/total pressure is in the range 0.2 to 0.9.

2. A co-polymer as claimed in claim 1, characterised in that it occurs in the form of spheroidal particles.

3. A co-polymer as claimed in claim 1, characterised in that it has a particle size distribution such that the ratio Dm:

Dn is comprised between 1.2 and 3.

4. A co-polymer of ethylene and 4-methyl-pentene-1 characterised in that it is in the form of a powder consisting of non-sticky particles having a mean diameter by mass, Dm, comprised between 300 and 1500 microns, and a particle size distribution such that the ratio Dm:

Dn is less than or equal to 3.5, and characterised in that it has;

(a) a content of units derived from 4-methyl-pentene-1 comprised between 4 and 15% by weight,

(b) a density comprised between 0.910 and 0.940,

(c) a bulk density comprised between 0.35 and 0.45 g/cm³,

(d) an unsaturation level of less than 0.2 double bonds per 1000 carbon atoms,

(e) a single melting point comprised between 116°

C. and 128°

C., determined by scanning differential calorimetric analysis after re-heating to 200°

C., cooling at the rate of 16°

C. per minute and heating at the rate of 16°

C. per minute,

(f) a structure with a small amount of long-chain branches such that g* is greater than or equal to 0.90 wherein g* is the ratio η

/η

₁, η

being the intrinsic viscosity of the co-polymer and η

₁ being the intrinsic viscosity of a linear polyethylene having the same weight average molecular weight as the said co-polymer.

5. A copolymer of ethylene and a hexene-1 characterized in that it is in the form of a powder consisting of non-sticky particles having a mean diameter by mass, Dm, comprised between 300 and 1500 microns, and a particle size distribution such that the ratio Dm:

Dn is less than or equal to 3.5, and characterized in that it has;

(a) a content of units derived from hexene-1 comprised between 4 and 15% by weight,

(b) a density comprised between 0.910 and 0.940,

(c) a bulk density comprised between 0.35 and 0.45 g/cm³,

(d) an unsaturation level of less than 0.2 double bonds per 1000 carbon atoms,

(e) a single melting point comprised between 116°

C. and 128°

C., determined by scanning differential calorimetric analysis after reheating to 200°

C., cooling at the rate of 16°

C. per minute and heating at the rate of 16°

C. per minute,

(f) a structure with a small amount of long-chain branches such that g* is greater than or equal to 0.90 wherein g* is the ratio η

/η

₁, η

being the intrinsic viscosity of the co-polymer and η

₁ being the intrinsic viscosity of a linear polyethylene having the same weight average molecular weight as the said co-polymer.