Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1995-07-19
2002-05-21
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...
C526S170000, C526S127000, C526S943000, C526S134000, C526S351000, C526S348000, C502S152000
Reexamination Certificate
active
06391991
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for the preparation of amorphous polymers of propylene.
The invention also relates to a process for the preparation of indene compounds suitable as metallocene ligands.
2. Description of the Prior Art
As it is well known, products of propylene homopolymerization can be either crystalline or amorphous. Whereas the polypropylene having isotactic or syndiotactic structure is crystalline, the polypropylene having essentially atactic structure appears to be amorphous. The atactic polypropylene, in the representation by the Fischer formula as described in “M. Farina, Topics Stereochem., 17, (1987), 1-111” shows methyl groups casually arranged from one or the other side of the polymeric chain. As described in the above mentioned publication, useful information on the structure can be obtained from N.M.R. analysis.
The amorphous polypropylene available on the market is mainly used in adhesive compositions and as additives for bitumens. Generally, it is a by-product of the isotactic polypropylene obtained in the presence of catalysts of the Ziegler-Natta type. The separation of small fractions of amorphous polypropylene from the remainder product however involves inconvenient separation processes with solvents.
More recently, in the polymerization reaction of olefins, catalysts based on metallocene compounds and alumoxane compounds have been used. Operating in the presence of these catalysts, polymers characterized by a narrow molecular weight distribution and endowed with structural characteristics of interest can be obtained.
In particular, by polymerizing propylene in the presence of metallocene catalysts, depending on the metallocene used crystalline or amorphous polypropylene can be obtained. However, the amorphous polypropylene obtainable in the presence of metallocene catalysts is generally endowed with low molecular weight.
U.S. Pat. No. 4,542,199 describes a catalytic system for the polymerization of olefins comprising a bis(cyclopentadienyl)zirconium and an alumoxane. From the polymerization reaction of propylene carried out in the presence of this catalyst, low molecular weight atactic polypropylene is obtained.
European patent application 283,739 describes a catalytic system for the polymerization of olefins comprising a partially substituted bis(cyclopentadienyl)zirconium and an alumoxane. From the polymerization reaction of propylene carried out in the presence of this catalyst, low molecular weight atactic polypropylene is obtained.
In U.S. Pat. No. 4,931,417, catalysts for the polymerization of olefins comprising a metallocene compound wherein two cyclopentadienyl rings are joined through a radical containing a silicon or germanium atom are described. The polymerization reaction of propylene carried out in the presence of these compounds partially substituted on the cyclopentadienyl rings gives rise to isotactic polypropylene, whereas with dimethylsilandiylbis(cyclopentadienyl)zirconium dichloride, low molecular weight atactic polypropylene is obtained.
In European patent application 399,347 a process for the polymerization of propylene in the presence of a catalyst comprising a metallocene having a cyclopentadienyl ring and a fluorenyl ring joined by a bridge, such as isopropylidene-(9-fluorenyl)(3-methylcyclopentadienyl)zirconium dichloride is described. An amorphous polypropylene is obtained, the structure of which however is not atactic, but is defined as syndioisoblocks. Namely, it is a structure wherein syndiotactic and atactic sequences alternate.
The international application WO 94/11406 describes a class of indenyl compounds substituted in the 2-position on the indenyl group. In the application it is stated that these compounds can be used as catalyst components for the polymerization of olefins. However, in the polymerization examples only homopolymers of ethylene and elastomeric copolymers of ethylene with propylene are prepared.
SUMMARY OF THE INVENTION
It has now been found that it is possible to prepare substantially amorphous polymers of propylene having high molecular weight, operating at temperatures of industrial interest, by carrying out the polymerization reaction of propylene in the presence of metallocene catalysts comprising particular bis-indenyl or bis-4,5,6,7-tetrahydroindenyl compounds substituted in the 2-position on the indenyl or tetrahydroindenyl groups.
Therefore, an object of the present invention consists of a process for the preparation of substantially amorphous polymers of propylene, comprising the polymerization reaction of propylene in the presence of a catalyst comprising the product of the reaction between:
(A) a metallocene compound selected from the bis-indenyl compounds of formula (I):
and the corresponding bis-4,5,6,7-tetrahydroindenyl compounds, wherein:
on each indenyl or tetrahydroindenyl group the substituents R
1
and R
2
, same or different from each other, are hydrogen atoms, —CHR
2
groups or —CHR— groups form a cycle comprising from 3 to 8 carbon atoms, wherein the R substituents are hydrogen atoms, C
1
-C
20
alkyl radicals, C
3
-C
20
cycloalkyl radicals, C
2
-C
20
alkenyl radicals, C
6
-C
20
aryl radicals, C
7
-C
20
alkaryl radicals or C
7
-C
20
aralkyl radicals and can contain Si or Ge atoms;
the substituents R
3
, R
4
, R
5
and R
6
, same or different from each other, are defined as R substituents, in addition two adjacent R
3
, R
4
, R
5
and R
6
substituents on the same ring can form a ring comprising from 5 to 8 carbon atoms; M is a transition metal atom of groups IVb, Vb or VIb of the Periodic Table;
substituents X, same or different from each other, are hydrogen atoms, halogen atoms, —R
7
, —OR
7
, —SR
7
, —NR
7
2
or —PR
7
2
groups where substituent R
7
are defined as substituent R; optionally pre-reacted with an organometallic compound of aluminium of formula AlR
8
3
or Al
2
R
8
6
, wherein substituents R
8
, same or different, are defined as substituent R or are halogen atoms; and
(B) at least a compound selected from (a) the organo-metallic compounds of aluminum containing at least a heteroatom selected from oxygen nitrogen and sulphur, optionally in admixture with an organometallic compound of aluminum of formula AlR
8
3
or Al
2
R
8
6
, wherein substituents R
8
, same or different, are defined as above, and (b) compounds capable of producing a metallocene alkyl cation.
Another object of the present invention is a process for the preparation of indene compounds of formula (VII):
suitable as metallocene ligands, which comprises the reaction of an aromatic compound of formula (VIII) with a compound of formula (IX), to obtain the indan-1-one of formula (X), wherein R
3
, R
4
, R
5
and R
6
have the above defined meaning, R
10
is a hydrogen atom or an alkyl radical C
1
-C
3
, Y is an halogen atom, according to the following reaction scheme:
and the following conversion into the corresponding indene (VII).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Among the metallocene compounds of formula (I), the preferred are those wherein, in each of the indenyl or tetrahydroindenyl groups the substituents R
3
are the same as substituents R
6
, and substituents R
4
are the same as substituents R
5
. More preferred are those in which all the substituents R
3
and R
6
are hydrogen atoms.
The transition metal M is preferably selected from titanium, zirconium, hafnium and vanadium, more preferably zirconium.
The substituents X are preferably chlorine atoms or a methyl radical.
Non limiting examples of metallocene compounds which can be used in the process of the present invention are:
bis(2-methyl-indenyl)zirconium dichloride,
bis(2,4,7-trimethyl-indenyl)zirconium dichloride,
bis(2,4,6-trimethyl-indenyl)zirconium dichloride,
bis(2,5,6-trimethyl-indenyl)zirconium dichloride,
bis(2,4,5,6,7-pentamethyl-indenyl)zirconium dichloride,
bis(2-ethyl-indenyl)zirconium dichloride,
bis(2-ethyl-4,7-dimethyl-indenyl)zirconium dichloride,
bis(2-ethyl-4,6-dimethyl-indenyl)zirconium dichloride,
bis(2-ethyl-5,6-dimethyl-ind
Balboni Davide
Piemontesi Fabrizio
Resconi Luigi
Basell Technology Company BV
Bryan Cave LLP
Choi Ling-Siu
Wu David W.
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