Metallocene products

Deals can create value on the technology side if they unite players with different (and, ideally, complementary) skills and strengths. That has been the rationale behind a number of recent technology-focused alliances, such as the one between Union Carbide and Exxon in polyolefines the former excels in process technology, the latter in metallocene technology. Clear synergies exist, since a producer can tailor a process to the specific needs and opportunities of new metallocene products. 

These materials are potent antivirial agents [37,38]. More recently we reported the synthesis of Group IVB metallocene products and the synthesis of Group IVB acyclovir polymers of the following structure from reactions with titanocene dichloride shown in (10) [39],... 

Cycloolefin copolymer (COC) is an amorphous, clear metallocene product of norbomene and ethylene with a spectrum of attractive performance characteristics. Thus, COC (MFI at 190 °C and 2.16 kg = 1.7 dg min, p = 1,020 kg m ) was blended with C2+6 LLDPE (MFI at 190 °C and 2.16 kg = 3.2 dg min , p = 920 kg m ). The mechanical properties of the blends indicate immiscibility, despite the increased LLDPE crystallinity. The presence of COC improved the thermo-oxidative stability. Quasi-static tensile tests showed that increasing fraction of COC in the blends accounts for an enhancement of the elastic modulus and a decrease in the strain at break, while tensile strength passes through a minimum. A significant reduction of the creep compliance of LLDPE could be achieved only for the COC fractions exceeding 20 wt% (Dorigato et al. 2010). 

Exxon Chemical and Union Carbide formed a joint venture to develop metallocene technologies. Exxon and DSM also set up a metallocene joint venture in 1996. Dow began production of 65,000 t/yr of metallocene products at Tarragona, Spain in 1996. 

Metallocene-catalyzed polyolefins represent the latest wave of developments in the history of the polyolefins industry. Developments began in 1942 with the introduction of LDPE, followed by HDPE and PP in 1957, and LLDPE in 1978. Today s embryonic metallocene products represent a basic renewal for polyolefin technology in general. 

TABLE 16 Narrow MW Distribution is a Prime Metallocene Product Attribute (Product Grades Tailored to Meet Application Needs)... 

Metallocene product Leading producers Commercial status Competitive materials... 

Most importantly, there is no output penalty using existing extrusion equipment. This is key since metallocene products are going to be widely accepted in the volume markets. Innovene with INSITE technology is clearly unique in this respect. 

Although metallocene types of structures have been known for several decades [18,19], their potential as commercial catalysts remained unrealized until 1980, when Kaminsky and coworkers [20,21] discovered that methylalumoxane improved their catalytic activity dramatically. Since that discovery, massive and intense research programs have been undertaken to bring metallocene products to coimnercial fruition. Reviews of the development of metallocene catalysts can be found in papers by Horton [22] and Kaminsky [23]. The reason for this enormous interest lies in the ability of metallocene catalysts to provide well-dehned polymer products, opening the way to the molecular engineering of resins with properties tailored to the precise needs of the end user. Particular effort has been expended to replace conventional (Ziegler-Natta-type) linear low density poly-... 

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