Catalysis in high density polyethylene (HDPE) manufacturing

• Published in: Applied catalysis. A, General Vol. 542; pp. 389 - 390
• Main Author: Jensen, Michael D.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science SA 25.07.2017
• Subjects: Addition polymerization; Biological evolution; Catalysis; Catalysts; Chromium; Formulations; High density polyethylenes; Inorganic materials; Magnesium chloride; Molecular weight; Molecular weight distribution; Porous materials; Silicon dioxide; United States > US
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2016.12.013

Two types of catalyses have dominated the HDPE industry for 65 years: Phillips (discovered at Phillips Petroleum Co. in 1951) and Ziegler (discovered by Karl Ziegler in 1953). During this time both have evolved from their initial formulations. For example. Phillips catalysts, initially chromium species deposited on amorphous silica, still contain chromium but are now supported on a multitude of other porous inorganic materials, including silica-titania, silica-magnesia, aIuminophosphates, aluminosulfates and halogenated matrices, all of which can be further tailored by the addition of alkylmetal cocatalysts in the polymerization reactor. Likewise, Ziegler catalysts, initially TICI3 and alkylaluminum, now usually contain MgCI2 or MgCl2 on SiO2 to boost activity and control polymer morphology. Additionally, various donor ligands can be added to tailor the molecular weight or comonomer distribution and the activity response to hydrogen. Because they serve different HDPE markets, these two catalyst types are not usually considered in competition with each other.