Polymerization process

Details Polymerization process Polymerization process

2000-11-30

2004-04-13

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...

C526S070000, C526S124300, C526S129000, C526S352000, C526S907000, C526S090000

Reexamination Certificate

active

06720396

ABSTRACT:

FIELD OF THE INVENTION
This invention relates generally to a process for polymerizing olefin(s) in the presence of a catalyst composition prepared in a manner that substantially reduces the time and the cost for making a catalyst composition. Most importantly, the method of making the catalyst composition results in improved process operability, particularly in a slurry process.
BACKGROUND OF THE INVENTION
Supported catalyst systems are widely used in olefin polymerization processes, particularly in a gas phase or a slurry phase. Typically for a supported catalyst, preparation of the catalyst involves dissolving a catalyst in a solvent, dissolving an activator or co-catalyst in a solvent and placing a support in a solution or reaction mixture with the catalyst and activator. Many techniques are known in the art that include adding each of these catalyst components in different orders, solutions, amounts, support materials, other components, etc., however, invariably the final catalyst composition is oftentimes washed in various solvents and/or dried to a solid state.
Examples of conventional supporting techniques are described in U.S. Pat. Nos. 4,701,432, 4,808,561, 4,912,075, 4,925,821, 4,937,217, 5,008,228, 5,238,892, 5,240,894, 5,332,706, 5,346,925, 5,422,325, 5,466,649, 5,466,766, 5,468,702, 5,529,965, 5,554,704, 5,629,253, 5,639,835, 5,625,015, 5,643,847, 5,665,665, 5,698,487, 5,714,424, 5,723,400, 5,723,402, 5,731,261, 5,759,940, 5,767,032, 5,770,664, 5,846,895 and 5,939,348 and U.S. application Ser. Nos. 271,598 filed Jul. 7, 1994, now U.S. Pat. No. 5,468,702, and 788,736 filed Jan. 23, 1997, now U.S. Pat. No. 6,090,740, and PCT publications WO 95/32995, WO 95/14044, WO 96/06187 and WO 97/02297, and EP-B1-0 685 494 all of which are herein fully incorporated by reference.
It is common practice to dry and/or evaporate the solvents in final stage for preparing a supported catalyst system. The drying and/or evaporating step is generally accomplished by elevating the temperature, using a vacuum, purging of inert gas or combinations thereof. The drying procedures generally result in the catalyst and activator being deposited on or in a support material resulting in a dry powder or granule supported catalyst system. It is in this physical form under an inert atmosphere that the supported catalyst system is typically stored and/or shipped for use in a polymerization process. The amount of time necessary for drying a supported catalyst system adds many hours to a catalyst manufacturing plant production schedule and adds a substantial energy cost.
There is much discussion in the literature on forming a supported catalyst system, and in addition re-slurrying the supported catalyst system in various liquids for use in particular a slurry polymerization process.
Thus, there is a need for an improved method for making a useful catalyst composition having improved performance and operability in the polymerization of olefin(s).
SUMMARY OF THE INVENTION
The invention is directed to a polymerization process utilizing a catalyst composition formed in a way that eliminates various steps conventionally used in the formation of a supported catalyst system.
In one embodiment, the invention relates to a process for polymerizing olefin(s) in the presence of a catalyst composition, the catalyst composition comprising a liquid, a catalyst compound, an activator, and a support, wherein the catalyst composition is utilized as is without drying or washing the catalyst composition. In a preferred embodiment, the catalyst composition of the mixture of the liquid, catalyst compound, activator and support is maintained for a period of time prior to introducing the catalyst composition to the polymerization process. In a most preferred embodiment, the polymerization process is a slurry process.
DETAILED DESCRIPTION OF THE INVENTION
Introduction
It has been discovered that a catalyst composition of a liquid, a support, a catalyst compound, and an activator that is maintained as a mixture for a period of time, and subsequently, used, as is, in a polymerization process results in better process operability and improved catalyst productivity in a polymerization process. The reduction, preferably the elimination, of the typical drying step in a conventional supported catalyst manufacturing process results in improved process economics and improved polymerization process, particularly in the slurry phase. These catalyst preparation techniques offer reduced catalyst manufacturing times and lower costs stemming from lower energy costs, lower vacuum costs, pressure reducing costs, lower purge gas costs, storage costs, etc. Furthermore, without being bound to any particular theory, it is believed that supporting a catalyst system often results in the lowering the overall productivity of a particular catalyst. Also, it is believed that that the support materials used deactivate some of the active catalyst species, and that a drying or dehydration step also lowers catalyst performance.
The inventive use of the catalyst composition of the invention in a polymerization process, in particular a slurry process, surprisingly results in better process operability and catalyst performance.
Catalyst Compounds
Any type of polymerization catalyst or catalyst system may be used to form the catalyst composition of the invention. Bulky ligand metallocene catalyst compounds and Group 15 containing bidentate or tridentate transition metal catalysts are preferred; however, catalyst compounds or activators that are sufficiently soluble in a liquid are desirable.
Conventional Transition Metal Catalysts
Conventional-type transition metal catalysts are those traditional Ziegler-Natta catalysts and Phillips-type chromium catalyst well known in the art. Examples of conventional-type transition metal catalysts are discussed in U.S. Pat. Nos. 4,115,639, 4,077,904, 4,302,565, 4,302,566, 4,482,687, 4,564,605, 4,721,763, 4,879,359 and 4,960,741 and British Patent Application 2,105,355, all of which are herein fully incorporated by reference. The conventional-type transition metal catalyst compounds that may be used in the present invention include transition metal compounds from Groups III to VIII, preferably IVB to VIB of the Periodic Table of Elements.
These conventional-type transition metal catalysts may be represented by the formula: MR
x
, where M is a metal from Groups IIIB to VIII, preferably Group IVB, more preferably titanium; R is a halogen or a hydrocarbyloxy group; and x is the valence of the metal M. Non-limiting examples of R include alkoxy, phenoxy, bromide, chloride and fluoride. Non-limiting examples of conventional-type transition metal catalysts where M is titanium or vanadium include TiCl
4
, TiBr
4
, Ti(OC
2
H
5
)
3
Cl, Ti(OC
2
H
5
)Cl
3
, Ti(OC
4
H
9
)
3
Cl, Ti(OC
3
H
7
)
2
Cl
2
, Ti(OC
2
H
5
)
2
Br
2
, TiCl
3
.1/3AlCl
3
and Ti(OC
12
H
25
)Cl
3
, and VOCl
3
, VCl
4
and VOCl
2
—OR where R is a hydrocarbon radical.
Conventional-type chromium catalyst compounds, often referred to as Phillips-type catalysts, suitable for use in the present invention include CrO
3
, chromocene, silyl chromate, chromyl chloride (CrO
2
Cl
2
), chromium-2-ethylhexanoate, chromium acetylacetonate (Cr(AcAc)
3
), and the like. Non-limiting examples are disclosed in U.S. Pat. Nos. 2,285,721, 3,242,099 and 3,231,550,which are herein fully incorporated by reference.
Still other conventional-type transition metal catalyst compounds and catalyst systems suitable for use in the present invention are disclosed in U.S. Pat. Nos. 4,124,532, 4,302,565, 4,302,566 and 5,763,723 and published EP-A2 0 416 815 A2 and EP-A1 0 420 436, which are all herein incorporated by reference
Typically, these conventional-type transition metal catalyst compounds excluding some convention-type chromium catalyst compounds are activated with one or more of the conventional-type cocatalysts described below.
Conventional-type Cocatalysts
Conventional-type cocatalyst compounds for the above conventional-type transition metal catalyst compounds may be represented by the formula

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