摘要:
A process for polymerizing an olefin is disclosed. The olefin is polymerized with a catalyst precursor in the presence of an activator and an organosilane modifier. Use of the organosilane increases polyolefin molecular weight. The process is easy to practice and affords polyolefins with conventional polymerization methods such as slurry polymerizations or gas-phase polymerizations.
摘要:
A supported olefin polymerization catalyst system and a method of making it are disclosed. The catalyst system comprises: (a) a support having mean particle size less than about 30 microns chemically treated with alumoxane; (b) an organometallic complex comprising a Group 3 to 10 transition or lanthanide metal, M, and at least one indenoindolyl ligand that is &pgr;-bonded to M; and (c) an activator. Chemical treatment with alumoxane and support mean particle size less than 30 microns are key to making supported indenoindolyl containing catalysts having high activity.
摘要:
A method for making ethylene polymers and copolymers is disclosed. The method uses a catalyst system comprising a low level of an aluminum-containing activator, a bridged indenoindolyl transition metal complex, and a treated silica support. The method enables economical preparation of ethylene copolymers having very low density. The silica-supported, bridged complexes incorporate comonomers efficiently and are valuable for a commercial slurry loop process. Use of a bridged indeno[2,1-b]indolyl complex provides exceptionally efficient comonomer incorporation, and gives polymers with a substantial and controlled level of long-chain branching. The method facilitates the production of a wide variety of polyolefins, from HDPE to plastomers.
摘要:
A supported olefin polymerization catalyst system and a method of making it are disclosed. The catalyst system comprises: (a) a support chemically treated with an organoaluminum, organosilicon, organomagnesium, or organoboron compound; (b) a single-site catalyst that contains a polymerization-stable, heteroatomic ligand; and (c) an activator. Chemical treatment is a key to making supported heterometallocenes that have high activity and long shelf-lives, and can effectively incorporate comonomers.
摘要:
Disclosed is a method of preparing an ultra-high molecular weight, linear low density polyethylene with a catalyst system that comprises a bridged indenoindolyl transition metal complex, a non-bridged indenoindolyl transition metal complex, an alumoxane activator and a boron-containing activator. The ultra-high molecular weight, linear low density polyethylene has a weight average molecular weight greater than 1,000,000 and a density less than 0.940 g/cm3.
摘要:
A process for polymerizing ethylene is disclosed. A magnesium chloride-alcohol is used to support an organometallic complex comprising a Group 3 to 10 transition metal and an indenoindolyl ligand. The supported organometallic complex is mixed with an activator and ethylene and the ethylene is polymerized. Use of magnesium chloride containing an alcohol as the support provides an unexpected boost in catalyst activity and improves polymer rheological properties.
摘要:
Ethylene and optional comonomers are polymerized using a supported metallocene catalyst, an alumoxane activator, and triisobutylaluminum (TIBAL). A silica support is first pretreated with a silane compound and then with an organoboron compound. The treated silica is then combined with a Group 4 metallocene complex and an alumoxane to generate a supported, activated catalyst. While it was previously thought that the particular support treatment technique used herein provided benefits only for polymerizations catalyzed by non-metallocene single-site complexes, it has now been found that similar benefits can be realized even with conventional metallocenes if TIBAL is selected as the scavenger.
摘要:
The invention relates to a process for the in-situ preparation of alkylated single-site transition metal catalysts by contacting a precatalyst with an alkylating agent in the presence of one or more olefin monomers in the polymerization system. The precatalyst, which is produced prior to introducing into the polymerization system, is obtained by contacting a transition metal complex and boron-containing ionizing agent, optionally, with a support.
摘要:
A single-site olefin polymerization catalyst is described. The catalyst comprises an activator and an organometallic compound that includes a Group 3 to 10 transition or lanthanide metal, M, and a modified boraaryl ligand. We surprisingly found that the catalyst is more active in olefin polymerization compared to other catalysts containing non-modified boraaryl ligands. Most surprisingly, the supported catalyst gives polyolefins with a multimodal molecular weight distribution having separate components of distinct molecular weight.
摘要:
A gas phase copolymerization of ethylene is disclosed. The process uses a supported single-site catalyst that contains a heteroatomic ligand and produces polyethylene that has a reduced density. Suitable heteroatomic ligands include boraaryl, azaborolinyl, pyridinyl, pyrrolyl, indolyl, carbazolyl and quinolinyl.