Process for the preparation of substantially amorphous...

Details Process for the preparation of substantially amorphous... Process for the preparation of substantially amorphous...

2000-03-02

2002-07-23

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...

C526S943000, C526S127000, C526S132000, C526S133000, C526S134000, C526S351000, C526S348000

Reexamination Certificate

active

06423796

ABSTRACT:

The present invention relates to a process for the preparation of substantially amorphous polymers of alpha-olefins. In particular, the present invention relates to a process for the preparation of substantially amorphous homo- and copolymers of propylene and compositions containing them together with isotactic polypropylene. The present invention relates also to a convenient process for the preparation of indenyl compounds useful for the preparation of metallocenes, which are used in the process for the preparation of substantially amorphous polymers of alpha-olefins.
Products of the propylene homopolymerization can be either crystalline or amorphous. Whereas the polypropylene having isotactic or syndiotactic structure is crystalline, the polypropylene having essentially atactic structure is amorphous.
Amorphous polypropylene finds applications as a component in hot melt adhesives, paper coatings and as a bitumen additive. Generally, it can be obtained as a side product from the preparation of isotactic polypropylene in the presence of heterogeneous Ziegler-Natta type catalysts. This product, however, has moderate molecular weight, broad molecular weight distribution, and contains some residual cristallinity. Moreover, the separation of the fraction of amorphous polypropylene from the remainder product involves an additional step of separation by means of solvents.
For use in a wider range of applications, notably in blends with crystalline polypropylene for PVC replacement, amorphous polypropylene having high molecular weight is required.
More recently, by polymerizing propylene in the presence of particular metallocene catalysts, amorphous polymers of propylene endowed with high molecular weights and a narrow molecular weight distribution have been obtained.
European patent application 604 917, for example, describes amorphous propylene polymers obtained in the presence of bridged bis-fluorenyl metallocenes. The structure of the polymers is substantially atactic, with the syndiotactic dyads being more numerous than the isotactic dyads.
In International application WO 95/00562 it is described a process for producing amorphous poly-alpha-olefins with a monocyclopentadienyl transition metal catalyst system. Both low and high molecular weight polymers can be obtained, with narrow molecular weight distributions. As for the polymers described in EP-A-604,917, also in this case the syndiotactic dyads are more abundant than the isotactic dyads.
These amorphous polymers of propylene find interesting applications in blends with cristalline polyolefins.
In International application WO 96/23838, for instance, there are described blends of high molecular weight amorphous polypropylene with lower molecular weight isotactic polypropylene. The amorphous polypropylene, which are produced by using the same catalyst as in WO95/00562, have more syndiotactic than isotactic dyads.
It would be desirable to make available amorphous alpha-olefin polymers endowed with high molecular weights and narrow molecular weight distributions, which are more miscible with isotactic poly-alpha-olefins. It would also be desirable to provide amorphous alpha-olefin polymers with improved elastomeric properties.
In European patent application EP-A-0 693 506 the preparation of substantially amorphous polymers of propylene in the presence of unbridged bis-indenyl or bis-4,5,6,7-tetrahydroindenyl compounds substituted in the 2-position on the indenyl or tetrahyroindenyl groups is described. In these polymers, the isotactic dyads are more numerous than the syndiotactic dyads. However, when the polymerization is carried out at temperatures of industrial interest, polymers of propylene endowed with low molecular weight are obtained.
In European patent application EP-A-0 584 609 it is described the preparation of polypropylene by means of a metallocene compound, which is used as a mixture of its racemic and meso isomeric form. The obtained polypropylene compositions contain fractions of amorphous and isotactic polypropylene. The miscibility of those fractions can still be improved.
U.S. Pat. No. 5,516,848 and U.S. Pat. No. 5,539,056 relate to the in situ preparation of polypropylene blends comprising high molecular weight amorphous polypropylene with lower molecular weight isotactic polypropylene. It is mentioned that blends containing low molecular weight amorphous polypropylene with high molecular weight isotactic polypropylene have poor elastic recovery properties, due to the stiffness of the isotactic polypropylene.
It has been surprisingly found that it is possible, operating at conditions of industrial interest, to prepare amorphous polymers of alpha-olefins having high molecular weights, narrow molecular weight distribution, with a predominance of isotactic dyads, by carrying out the polymerization reaction in the presence of metallocene catalysts comprising a particular substituted, single-atom-bridged, bis-indenyl compound.
Therefore, the present invention provides a process for the preparation of polymers of alpha-olefins, particularly of propylene, in the presence of a catalyst comprising the product obtainable by contacting:
(A) a metallocene compound in the racemic form of the formula (I):
 wherein
substituents R
1
are hydrogen atoms;
R
2
and R
3
are, independently from each other, 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;
or where R
2
and R
3
can be joined together to form a 4 to 6 membered ring or a 6 to 20 fused ring system;
R
4
and R
5
, same or different, are hydrogen atoms or —CHR
8
R
9
groups;
R
4
and R
5
can form a ring having 3 to 8 carbon atoms, which can contain hetero atoms;
the R
8
and R
9
substituents, 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
6
and R
7
substituents, same or different, are hydrogen, C
1
-C
10
-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; and optionally two adjacent R
6
and R
7
substituents can form a ring comprising from 5 to 8 carbon atoms;
M is 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, a R
10
, OR
10
, OSO
2
CF
3
, OCOR
10
, SR
10
, NR
10
, or PR
10
2
group, wherein the substituents R
10
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
-alkylaryl radical, optionally containing silicon or germanium atoms;
p is an integer from 0 to 3, p 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.
In the metallocene of formula (I) the transition metal M is preferably selected from titanium, zirconium and hafnium.
More preferably, the transition metal M is zirconium.
The X substituents are preferably chlorine atoms or methyl groups.
The R
6
and R
7
substituents are preferably hydrogen atoms.
Non-limiting examples of metallocene compounds of formula (I) suitable for use in the process of the invention are:
methylene-bis(3-isopropyl-indenyl)zirconium dichloride and dimethyl;
isopropylidene-bis(3-isopropyl-indenyl)zirconium dichloride and dimethyl;
cyclopentylidene-bis(3-isopropyl-indenyl)zirconium dichloride and dimethyl;
cyclohexylidene-bis(3-isopropyl-indenyl)zirconium dichloride and dimethyl;
methylene-bis[3-(1-methylpropyl)-indenyl]zirconium dichloride and dimethyl;
isopropylidene-bis[3-(1-methylpropyl)-indenyl]zirconium dichloride and dimethyl;
cyclopentylidene-bis[3-(1-methylpropyl)-inden

Affiliated with

Also associated with

Rating

Process for the preparation of substantially amorphous... 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 the preparation of substantially amorphous..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the preparation of substantially amorphous... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2838406