摘要:
It has been found that the use of at least one unsupported metallocene polymerization catalyst with at least one supported metallocene polymerization catalyst in the polymerization of olefins allows for better control of the polymerization, especially gas phase polymerization. Such a system takes advantage of the high activity of the unsupported catalyst and the stability of a supported catalyst. Additionally, the relative timing of the addition of the supported and unsupported catalysts to a reaction system can be used to control a continuous polymerization reaction by stabilizing the reactor bed with the supported catalyst prior to addition of the unsupported catalyst.
摘要:
A mixed catalyst composition comprising a) a solid Ziegler-Natta catalyst; b) a liquid single site catalyst; and c) at least one activating cocatalyst is provided. Polymers having a broad or bimodal molecular weight distribution may be made with this catalyst composition.
摘要:
This invention comprises a metallocene catalyst system for the production of high molecular weight polyolefins, particularly polyethylene and higher poly-alpha olefins, and copolymers of ethylene and/or alpha olefins with other unsaturated monomers, including diolefins, acetylenically unsaturated monomers and cyclic olefins. The catalyst system is highly active, at low ratios of Al to transition metal, and hence catalyzes the production of a polyolefin product containing low levels of catalyst metal residues. The catalyst system comprises (i) a metallocene precursor (Component A), aluminoxane (Component B), and phenolic modifier (Component C) or (ii) the reaction product of a metallocene precursor with a phenolic compound (Component A′) and aluminoxane (Component B). There is also provide a polymerization process using the catalyst and the product so produced.
摘要:
A process for the production of a catalyst precursor comprising reacting (a) a metallocene dihalide; (b) a compound of the formula: ##STR1## wherein each Q is the same or different and is independently selected from the group consisting of O, NR, CR.sub.2, and S; E is either C or S; Z is selected from the group consisting of --OR, --NR.sub.2, --CR.sub.3, --SR, --SiR.sub.3, --PR.sub.2, --H, and a substituted or unsubstituted aryl group; and each R is independently a group containing carbon, silicon, nitrogen, oxygen, and/or phosphorus; and (c) a trialkylamine.
摘要:
Bimodal polyethylene compositions and methods for making the same are provided. In at least one specific embodiment, the bimodal polyethylene composition can include a high molecular weight component having a weight average molecular weight (Mw) of from about 400,000 to about 950,000. The bimodal polyethylene composition can also include a low molecular weight component having a weight average molecular weight (Mw) of from about 3,000 to about 100,000. The high molecular weight component can be present in an amount ranging from about 25 wt % to about 40 wt % of the bimodal polyethylene composition. The bimodal polyethylene composition can also have a percent die swell of less than about 80%.
摘要:
A polymerization catalyst system and polymerization processes using the catalyst systems are disclosed. The polymerization catalyst systems may include a) a first catalyst compound, and b) a second catalyst compound, wherein the first catalyst compound includes an oxadiazole-containing compound. In some embodiments, the oxadiazole-containing compound has essentially no hydrogen response, thus allowing better and/or tailored control of product properties when producing polymers using the catalyst system.
摘要:
A supported catalyst composition having improved flow properties is disclosed comprising an alkylalumoxane, a metallocene-alkyl an inorganic oxide support having an average particle size of from 0.1 to 50 μm and calcined at a temperature greater than 600° C., and optionally an antifoulant agent and. In one embodiment, the metallocene-alkyl is a Group 4, 5 or 6 metallocene-alkyl, and in another embodiment is a hafnocene-alkyl. Also disclosed is a method of polymerization using such a supported catalyst composition.
摘要:
The invention provides for polymerization catalyst compositions, and for methods for introducing the catalyst compositions into a polymerization reactor. More particularly, the method combines a catalyst component containing slurry and a catalyst component containing solution to form the completed catalyst composition for introduction into the polymerization reactor. The invention is also directed to methods of preparing the catalyst component slurry, the catalyst component solution and the catalyst compositions, to methods of controlling the properties of polymer products utilizing the catalyst compositions, and to polymers produced therefrom.
摘要:
The invention provides for polymerization catalyst compositions, and for methods for introducing the catalyst compositions into a polymerization reactor. More particularly, the method combines a catalyst component containing slurry and a catalyst component containing solution to form the completed catalyst composition for introduction into the polymerization reactor. The invention is also directed to methods of preparing the catalyst component slurry, the catalyst component solution and the catalyst compositions, to methods of controlling the properties of polymer products utilizing the catalyst compositions, and to polymers produced therefrom.
摘要:
A polymerization catalyst system and a method for preparing the catalyst system is disclosed. The catalyst system includes a bulky ligand metallocene catalyst compound, preferably containing a single cyclopentadienyl or substituted cyclopentadienyl-type ring system, a Group 13 element containing first modifier, and a cycloalkadiene second modifier. The present invention also provides a process for polymerizing olefin(s) utilizing the catalyst systems described herein.