Process for the preparation of copolymers of ethylene with...

Details Process for the preparation of copolymers of ethylene with... Process for the preparation of copolymers of ethylene with...

1999-12-17

2002-09-10

Wu, David W. (Department: 1713)

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S159000, C526S348200, C526S348500, C526S348600

Reexamination Certificate

active

06448350

ABSTRACT:

The present invention relates to a process for the preparation of copolymers of ethylene with alpha-olefins.
Metallocene compounds with two bridged cyclopentadienyl groups are known as catalyst components for the homo- and copolymerization reaction of olefins.
For exanmle, U.S. Pat. No 5,001,205 discloses the prepa ration of copolymers of ethylene with alpha-olefins in the presence of a catalytic system comprising a bis-cyclopentadienyl compound of Zr, Ti and Hf and methylalumoxane (MAO) as cocatalyst. The working examples describe the copolymerization of ethylene with propylene in the presence of bridged or unbridged (tetrahydroindenyl)zirconium dichloride.
Although the homogeneity of the alpha-olefin distribution in the chain is improved with respect to copolymers obtained from conventional titanium- or vanadium-based Ziegler-Natta type catalysts, it is still not satisfactory and a further improvement is highly desirable. Metallocene compounds having two cyclopentadienyl moieties bridged by a single atom are also known.
For example, PCT application WO 96/22995 discloses a class of single carbon bridged metallocenes, and their use in catalysts for the polymerization of olefins, particularly of propylene. The class of metallocene compounds which is indicated as especially suitable for use in propylene polymerizations is that of the single-carbon-bridged bis-indenyls wherein the indenyl moieties are substituted in the 3-position with carbon, silicon or germanium atoms having three hydrocarbon substituents. Neither are reported examples of copolymerizations of ethylene with an alpha-olefin, nor is given any information about the properties of the obtainable ethylene copolymers. Particularly, there are no data about the comonomer distribution along the polymer chain.
It would be desirable to select catalysts capable of yielding ethylene copolymers having an improved homogeneity of the distribution of the comonomer units along the polymer chain. It has now been unexpectedly found that it is possible to prepare ethylene-based copolymers having high molecular weight, and in which the distribution of the comonomer units in the polymeric chain is extremely homogeneous, operating at temperatures of industrial interest, by carrying out the polymerization reaction of ethylene in the presence of metallocene catalysts comprising particular single atom bridged bis-indenyl compounds substituted in the 3-position on the indenyl group.
Therefore, according to a first aspect, the present invention provides a process for the preparation of copolymers of ethylene, comprising the polymerization reaction of ethylene with at least one comonomer selected from alpha-olefin, cycloolefins and polyenes, in the presence of a catalyst comprising the product obtainable by contacting:
(A) A Metallocene Compound of the Formula (I):
wherein
substituents R
1
are hydrogen atoms or C
1
-C
20
-alkyl groups,
substituents R
2
are CHR
10
R
11
, SiR
12
R
13
R
14
or GeR
15
R
16
R
17
groups,
wherein: R
10
, R
11
, R
12
, R
15
are hydrogen atoms, C
1
-C
20
-alkyl, C
3
-C
20
-cycloalkyl, C
2
-C
20
-alkenyl, C
6
-C
20
-aryl, C
7
-C
20
-alkylaryl or C
7
-C
20
-arylalkyl radicals, optionally silicon or germanium atoms;
R
13
, R
14
, R
16
, R
17
are C
1
-C
20
-alkyl, C
3
-C
20
-cycloalkyl, C
2
-C
20
-alkenyl, C
6
-C
20
-aryl, C
7
-C
20
-alkylaryl or C
7
-C
20
-arylalkyl radicals, optionally containing silicon or germanium atoms;
R
3
and R
4
, same or different, are hydrogen atoms or —CHR
5
R
6
groups;
R
3
and R
4
can form a ring having 3 to 8 carbon atoms which can contain hetero atoms;
R
5
and R
6
, same or different, are hydrogen atoms, C
1
-C
20
-alkyl, C
3
-C
20
-cycloalkyl, C
2
-C
20
-alkenyl, C
6
-C
20
-aryl, C
7
-C
20
-alkylaryl or C
7
-C
20
-arylalkyl radicals, which can form a ring having 3 to 8 carbon atoms which can contain hetero atoms;
the R
7
substituents, same or different, are a C
1
-C
20
-alkyl, C
3
-C
20
-cycloalkyl, C
2
-C
20
-alkenyl, C
6
-C
20
-aryl, C
7
-C
20
-alkylaryl or C
7
-C
20
-arylalkyl radical, optionally containing silicon or germanium atoms; and optionally two adjacent R
7
substituents can form a ring comprising from 5 to 8 carbon atoms, n being an integer from 0 to 4;
M is an atom of a transition metal selected from those belonging to group 3, 4, 5, 6 or to the lanthanide or actinide groups in the Periodic Table of the Elements (new IUPAC version), X, same or different, is a monoanionic ligand, such as a hydrogen atom, a halogen atom, an R
8
, OR
8
, OSO
2
CF
3
, OCOR
8
, SR
8
, NR
8
2
or PR
8
2
group, wherein the substituents R
8
are a C
1
-C
20
-alkyl, C
3
-C
20
-cycloalkyl, C
2
-C
20
-alkenyl, C
6
-C
20
-aryl, C
7
-C
20
-alkylaryl or C
7
-C
20
-aryl-alkyl radical, optionally containing silicon or germanium atoms;
p is an integer of from 0 to 3, being equal to the oxidation state of the metal M minus two; and
(B) An Alumoxane and/or a Compound Capable of Forming an Alkyl Metallocene Cation.
The transition metal M is preferably selected from titanium, zirconium and hafnium.
The X substituents are preferably chlorine atoms or methyl groups.
The R
1
and R
7
substituents are preferably hydrogen atoms.
Non-limiting examples of metallocene compounds suitable for use in the process of the invention are:
methylene-bis(3-methyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-methyl-indenyl)zirconium dichioride and dimethyl;
methylene-bis(3-ethyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-ethylndenyl)zirconium dichloride and dimethyl;
methylene-bis(3-dimethylsilyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-dimethylsilyl-indenyl)zirconum dichioride and dimethyl;
methylenie-bis(3-dimethylgermnyl-indenyl)zirconium dichioride and dimethyl;
isopropylidene-bis(3-dimethylgermyl-indenyl)zirconiumn dichioride and dimethyl;
methylene-bis(3-trimethylsilyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-trimethylsilyl-indenyl)zirconium dichioride and dimethyl;
methylene-bis(3-triethylsilyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-triethylsyl-indenyl)zirconium dichloride and dimethyl;
methylene-bis(3-trimethylgermylindenyl)zircornum dichioride and dimethyl;
isopropylidene-bis(3-trimethylermyl-indenyl)zirconium dichioride and dimethyl;
methylene-bis(3-diphenylsilyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-diphenylsilyl-indenyl)zirconium dichloride and dimethyl;
methylenc-bis(3-diethylsilyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-diethylsilyl-indenyl)zirconium dichloride and dimethyl;
methylene-bis(2-methyl-3-trimethylsilyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(2-methyl-3-trimethylsilyl-indenyl)zirconium dichloride and dimethyl;
methylene-bis(2-methyl-3-diethylsilyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(2-methyl-3-diethylsilyl-indenyl)zirconium dichloride and dimethyl;
methylene-bis(3-benzylsilyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-benzylsilyl-indenyl)zirconium dichloride and dimethyl;
methylene-bis(3-cyclopentylsilyl-indenyl)zirconium dichioride and dimethyl;
isopropylidene-bis(3-cyclopentylsilyl-indenyl)zirconium dichloride and dimethyl;
methylene-bis(2-ethyl-3-diethylsilyi-indenyl)zirconiun dichloride and dimethyl;
isopropylidene-bis(2-ethyl-3-diethylsilyl-indenyl)zirconium dichloride and dimethyl.
In the metallocene compound of formula (I) in which R
2
is a CHR
10
R
11
group, preferably R
10
is different from a hydrogen atom. More preferably, both R
10
and R
11
are different from an hydrogen atom.
Particularly interesting metallocenes of formula (I) for use in the process of the invention are those in which R
1
is an hydrogen atom and R
2
is a CHR
10
R
11
group.
Non-limiting examples belonging to this class are:
methylene-bis(3-isopropyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-isopropyl-indenyl)zirconium dichloride and dimethyl;
methylene-bis(3-isobutyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-isobutyl-indenyl)zirconium di

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