 Use of thermoplastic elastomers for improving the stability of polyolefins to ionizing radiation |
| What is claimed is: 1. A method for improving the stability of a polyolefin base polymer to ... |
|
| Blends of linear low density ethylene copolymers |
| I claim: 1. A polymer blend comprising a linear low density copolymer of ethylene with an olefin ... |
|
| Impact copolymer compositions |
| What is claimed is: 1. A polypropylene impact copolymer composition consisting essentially of a ... |
|
| Molding composition |
| OF THE INVENTION The molding composition of the present invention employs mixtures of several ... |
|
| Asbestos-free friction material |
| What we claim is: 1. An asbestos-free friction material comprising 5 to 25% by weight of a ... |
|
| Composition comprising a metal salt and metal powder therefrom by the calcining thereof |
| OF THE INVENTION Disclosed herein is a composition that is non-fluid substance of an essentially ... |
|
| Process for the production of modified polyolefin |
| OF THE INVENTION A feature of the present invention is that the organosilane compound added to ... |
|
|
***WITHDRAWN PATENT AS PER THE LATEST USPTO WITHDRAWN LIST*** *** NO IMAGES AVAILABLE*** Homogeneous-heterogeneous catalyst system for polyolefins
| Details |
Inventors: Shamshoum, Edwar S.; Elder, Michael J.; Reddy, Baireddy R.; Rauscher, David J.;
Assignee: Fina Technology, Inc. (Dallas, TX)
Primary Examiner: Schofer; Joseph L.
Assistant Examiner: Wu; David
Attorney, Agent or Firm: Wheelington; Jim D., Cheairs; M. Norwood, Abokhair; John K.
This invention concerns a catalyst system comprising at least one homogeneous catalyst and at least one heterogeneous catalyst, specifically, a metallocene catalyst and a conventional Ziegler-Natta catalyst, respectively. This invention is useful in the polymerization of any polymer in which separate polymerizations with a homogeneous catalyst and with a heterogeneous catalyst are possible, but preferably, polymerization of olefins, more preferably, .alpha.-olefins, and, most preferably, propylene. This invention provides a catalyst system which facilitates use of a homogeneous catalyst but eliminates the disadvantages of such a system. This invention produces a polymer with molecular weight distribution (MWD) as broad or broader than the MWD of the heterogeneous catalyst alone. Hydrogen can be used to control molecular weight distribution of a polymer produced with this invention. |
|
DETAILED DESCRIPTION OF THE INVENTION The multi-catalyst system of the present invention is useful in the polymerization of any polymer in which separate polymerizations with a homogeneous catalyst and with a heterogeneous catalyst are possible.
Preferably, the multi-catalyst system is useful in the polymerization of olefins, more preferably, .
alpha.
-olefins, and, most preferably, propylene.
The multi-catalyst system of the present invention is obtained by mixing the components of at least one homogeneous catalyst system and at least one heterogeneous system.
The components may be combined in any order.
Generally, the components of a homogeneous catalyst system are a metallocene compound and an ionizing agent.
Generally, the components of a heterogeneous catalyst system are an aluminum alkyl and a transition metal compound with, optionally, an electron donor.
Any of the conventional heterogeneous Ziegler-Natta transition metal compound catalyst components can be used as the heterogeneous catalyst of the catalyst system of the present invention.
The compound is preferably of the general formula MR.
sup.
+.
sub.
x where M is the metal, R.
sup.
+ is a halogen or a hydrocarbyloxy and x is the valence of the metal.
Preferably, M is a Group IVB, VB or VIB metal, more preferably a Group IVB, and most preferably titanium.
Preferably, R.
sup.
+ is chlorine, bromine, an alkoxy or a phenoxy, more preferably chlorine or ethoxy and most preferably, chlorine.
Illustrative examples of the transition metal compound catalyst components are TiCl.
sub.
4, TiBr.
sub.
4, Ti(OC.
sub.
2 H.
sub.
5).
sub.
3 Cl, Ti(OC.
sub.
2 H.
sub.
5)Cl.
sub.
3, Ti(OC.
sub.
4 H.
sub.
9).
sub.
3 Cl, Ti(OC.
sub.
3 H.
sub.
7).
sub.
2 Cl.
sub.
2, Ti(OC.
sub.
6 H.
sub.
13).
sub.
2 Cl.
sub.
2, Ti(OC.
sub.
2 H.
sub.
5).
sub.
2 Br.
sub.
2 and Ti(OC.
sub.
12 H.
sub.
25)Cl.
sub.
3.
Mixtures of the transition metal compounds may be used.
No restriction on the number of transition metal compounds is made as long as at least one transition metal compound is present.
The transition metal compound may be either supported or unsupported
|
| Related patents |
|
|
Catalyst for polymerizing an olefin and method for producing an olefin polymer
We claim: 1. A catalyst for polymerizing an olefin which consists essentially of a product obtained by contacting (A) a metallocene transition metal compound, (B) at ...
|
|
|
Process for preparing biaxially oriented polypropylene film suitable for twist wrapping
It is therefore an object of the instant invention to provide a multilayered, coextruded, highly transparent, biaxially oriented polypropylene film which has good ...
|
|
|
Process for the production of a biaxially highly oriented polypropylene film
The propylene polymer of the base ply (or single ply, if there are no top plies) is preferably essentially a homopolymer; that is, there are preferably essentially no ...
|
|
|
Process for making a drag shield for a power mower
With the problems of the prior art in mind, the present invention includes two opposing and spaced apart rigid members of a first polymer material connected together by ...
|
|
|
Process for producing a chloromethylated polymer
We claim: 1. A process for producing a chloromethylated polymer by reacting styrene polymer particles with chloromethyl methyl ether in the presence of a catalyst, ...
|
|
|
Graft polymers of vinyl chloride on unsaturated olefinic elastomers and process for the preparation thereof
Having thus described our invention, what we desire to secure by Letters Patent and hereby claim is: 1. An impact resistant polymeric composition comprising a mixture of ...
|
|
|
Method of polymerizing vinyl halide with olefin polymers and copolymers and compositions thereof
What is claimed is: 1. In a process for the preparation of a vinyl chloride polymer comprising polymerizing in bulk in liquid phase in the presence of a trunk polymer ...
|
|
|
Method of preparing vinyl halide polymers and copolymers with polyolefins
OF THE INVENTION AND PREFERRED EMBODIMENTS THEREOF Except for the above-defined improvements of the invention, the reactants and reaction conditions, e.g. reaction ...
|
|
|
Ceramic tile adhesive water resistant compositions based on copolymers emulsions
I claim: 1. A ceramic tile adhesive composition containing from 20 to 90% by weight of the total weight of the composition of at least one filler, a zinc compound and an ...
|
|
|
Thermoplastic molding materials based on polyamide blends
We claim: 1. A thermoplastic molding material containing, as essential components, A) 20-98% by weight of a partly aromatic amide copolymer essentially consisting of a....
|
|
|
Adhesives and Rubbers 
