Process for polymerizing alpha-olefins

Details Process for polymerizing alpha-olefins Process for polymerizing alpha-olefins

2000-03-10

2002-12-17

Lu, Caixia (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S163000, C526S165000, C526S352000, C526S943000, C526S132000, C526S133000, C502S132000

Reexamination Certificate

active

06495640

ABSTRACT:

The present invention relates to a process for polymerizing alpha-olefins.
It is known practice to polymerize alpha-olefins using solid catalysts comprising a transition metal compound containing one or more cyclopentadienyl ligands, an aluminoxane and a support. Patent application EP-A-0 206 794 describes a process for polymerizing ethylene, in which a solid catalyst of this kind is used together with methylaluminoxane or triethylaluminium, which are added to the polymerization medium to capture poisons therein, such as oxygen and water. Such a process leads to the manufacture, in relatively low catalytic yields, of polyethylenes with a low bulk density (BD), which has a negative impact on the production efficiency of the polymerization plants.
Patent application EP-A-314 797 describes a process for polymerizing ethylene using a supported catalyst based on a compound containing cyclopentadiene ligands, an aluminoxane and a dialkylaluminium alkoxide. Such a process leads to the manufacture, in relatively low catalytic yields, of resins containing a large amount of fines.
A polymerization process has now been found which does not have the abovementioned drawbacks and which gives higher catalytic yields of &agr;-olefin polymers with a bulk density which is markedly higher than that obtained in the known processes.
To this end, the present invention relates to a process for polymerizing alpha-olefins, in which at least one alpha-olefin is placed in contact, under polymerizing conditions, with a catalytic system comprising
(a) a solid catalyst comprising (i) a compound of a transition metal from groups 4 to 6 of the Periodic Table, containing at least one cyclopentadiene ligand which may be substituted, (ii) an activator chosen from aluminoxanes and ionizing agents, and (iii) a porous polymeric support with an intraparticulate pore volume, generated by pores with a radius of from 1000 to 75,000 Å, of at least 0.2 cm
3
/g, and
(b) at least one organoaluminium compound corresponding to the general formula R
3−n
Al(Y′)
n
in which 0.9<n≦3; Y′ represents a group chosen from —OR′, —SR′ and —NR′R″; R and R′ independently represent an alkyl group comprising from 1 to 20 carbon atoms, an aryl, alkylaryl or arylalkyl group comprising from 6 to 30 carbon atoms, and R″ represents a hydrogen atom, an alkyl group comprising from 1 to 20 carbon atoms or an aryl, alkylaryl or arylalkyl group comprising from 6 to 30 carbon atoms.
According to the present invention, the term “alpha-olefin” means olefins with terminal unsaturation containing from 2 to 20 carbon atoms, preferably from 2 to 8 carbon atoms, such as, more particularly, ethylene, propylene, 1-butene, 1-pentene, 1-hexene and 1-octene.
The solid catalyst (a) used in the process according to the present invention comprises the transition metal compound (i) and the activator (ii) on the support (iii). It goes without saying that compounds other than compounds (i) and (ii) can be supported on the support (iii). Similarly, several compounds (i) and/or (ii) can be supported on the same support.
The transition metal compound (i) which can be used according to the present invention is usually chosen from the compounds of formulae
Q
a
(C
5
H
5−a−b
R
1
b
)(C
5
H
5−a−c
R
2
c
)MeXY  (1)
and
Q′
a
(C
5
H
5−a−d
R
3
d
)ZMeXY  (2)
in which
Q represents a divalent linking group between the two cyclopentadiene ligands (C
5
H
5−a−b
R
1
b
) and (C
5
H
5−a−c
R
2
c
),
Q′ represents a divalent linking group between the cyclopentadiene ligand (C
5
H
5−a−d
R
3
d
) and the group Z,
a is 0 or 1,
b, c and d are integers which satisfy the conditions 0≦b≦5, 0≦c≦5 and 0≦d≦5 when a is 0 and 0≦b≦4, 0≦c≦4 and 0≦d≦4 when a is 1,
R
1
, R
2
and R
3
each represent hydrocarbon-based groups containing from 1 to 20 carbon atoms, which can be linked to the cyclopentadiene ring in the form of a monovalent group, or which can be linked to each other so as to form a ring adjacent to the cyclopentadiene ring, halogen atoms, alkoxy groups containing from 1 to 12 carbon atoms, hydrocarbon-based groups containing silicon, of formula
—Si(R
4
)(R
5
)(R
6
), phosphorus-containing hydrocarbon-based groups of formula —P(R
4
)(R
5
), nitrogen-containing hydrocarbon-based groups of formula —N(R
4
)(R
5
) or boron-containing hydrocarbon-based groups of formula —B(
4
)(R
5
) in which R
4
, R
5
and R
6
represent hydrocarbon-based groups containing from I to 24 carbon atoms, provided that when b, c or d is 2 or more and/or when there is a plurality of groups R
1
, R
2
or R
3
, these groups may be identical or different,
Me represents a transition metal from groups 4 to 6 of the Periodic Table,
Z represents an oxygen atom, a sulphur atom, an alkoxy group or thioalkoxy group containing from 1 to 20 carbon atoms, a nitrogen-containing or phosphorus-containing hydrocarbon-based group containing from 1 to 40 carbon atoms or a hydrocarbon-based group containing from 1 to 20 carbon atoms, provided that one bond of the group Z is linked to the group Q′ when a is 1, and
X and Y, which may be identical or different, each represent a hydrogen atom, a halogen atom, a hydrocarbon-based group, an alkoxy group, an amino group, a phosphorus-containing hydrocarbon-based group or a silicon-containing hydrocarbon-based group containing from 1 to 20 carbon atoms.
The preferred compounds (i) of fon-nula (1) are generally such that
Q represents an alkylene group containing 1 or 2 carbon atoms which can be substituted with alkyl or aryl groups containing from 1 to 10 carbon atoms, or a dialkylgermnanium or dialkylsilicon group containing from 1 to 6 carbon atoms,
a is 0 or 1,
b, c and d are integers which satisfyr the conditions 0≦b≦5, 0≦c≦5 and 0≦d≦5 when a is 0 and 0≦b≦4, 0≦c≦4 and 0≦d≦4 when a is 1,
R
1
and R
2
represent alkyl, alkenyl, aryl, alkylaryl, alkenylaryl or arylalkyl groups containing from 1 to 20 carbon atoms, several groups R
1
and/or several groups R
2
possibly being linked to each other so as to form a ring containing from 4 to 8 carbon atoms,
Me is zirconium, hafiiium or titanium,
X and Y represent halogen atoms or hydrocarbon-based groups chosen from alkyls, aryls and alkenyls containing from 1 to 10 carbon atoms.
The compounds which are particularly preferred are those of formula (1) in which Q is a linking group chosen from dimethylsilyl and diphenylsilyl, ethylene and methylenes and ethylenes substituted with alkyl or aryl groups containing from 1 to 8 carbon atoms. Compounds of formula (1) which are particularly suitable are the compounds in which the ligands (C
5
H
5−a−b
R
1
b
) and (C
5
H
5−a−c
R
2
c
) are chosen from cyclopentadienyls, indenyls and fluorenyls which may be substituted.
The preferred compounds (i) of formula (2) are usually such that
a is 1,
Q′ represents an alkylene linking group containing 1 or 2 carbon atoms which may be substituted with alkyl or aryl groups containing from 1 to 10 carbon atoms, or a dialkylgermanium or dialkylsilicon group containing from 1 to 6 carbon atoms,
R
3
represents an alkyl, alkenyl, aryl, alkylaryl, alkenylaryl or arylalkyl group containing from 1 to 20 carbon atoms, two groups R
3
possibly being linked to each other to form a ring containing from 4 to 8 carbon atoms,
Me is zirconium, hafriium or titanium,
X and Y represent halogen atoms or hydrocarbon-based groups chosen from alkyls, aryls, and alkenyls.
Compounds (i) of formula (2) which give good results are the compounds in which the ligand (C
5
H
5−a−d
R
3
d
) is a cyclopentadienyl, indenyl or fluorenyl which may be substituted and Z is an amino group.
Preferred compounds (i) according to the present invention are the compounds of formula (1).
The activator (ii) is chosen from aluminoxanes and ionizing agents. The term “aluminoxanes” means compounds corresponding to the formulae R
7
—(AlR
7
—O)
m

Affiliated with

Also associated with

Rating

Process for polymerizing alpha-olefins does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for polymerizing alpha-olefins, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for polymerizing alpha-olefins will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2953998