High density polyethylene, HDPE processing

The slurry suspension and the gas phase processes are the two main categories of processes to produce high density polyethylene. HDPE processes can be further sub-categorised into ... 

High density polyethylene (HDPE) is defined by ASTM D1248-84 as a product of ethylene polymerisation with a density of 0.940 g/cm or higher. This range includes both homopolymers of ethylene and its copolymers with small amounts of a-olefins. The first commercial processes for HDPE manufacture were developed in the early 1950s and utilised a variety of transition-metal polymerisation catalysts based on molybdenum (1), chromium (2,3), and titanium (4). Commercial production of HDPE was started in 1956 in the United States by Phillips Petroleum Company and in Europe by Hoechst (5). HDPE is one of the largest volume commodity plastics produced in the world, with a worldwide capacity in 1994 of over 14 x 10 t/yr and a 32% share of the total polyethylene production. 

High-density polyethylene (HDPE) is produced by a low-pressure process in a fluid-bed reactor. Catalysts used for HDPE are either of the Zieglar-type (a complex of A1(C2H5)3 and a-TiCl4) or silica-alumina impregnated with a metal oxide such as chromium oxide or molybdenum oxide. 

To demonstrate this technology, we targeted a copolymer with blocks of both high density polyethylene (HDPE, density 0.94 g cm 3) and very low density polyethylene (VLDPE, density -0.88 g cm 3). Process and product characterization details are given in Table 6. We chose the pyridylamide precatalyst 18 [41] for this study due to its high comonomer reactivity, high M°, and demonstrated CCTP ability. 

Sclair A process for polymerizing ethylene. Depending on the co-monomer used, the product can be linear low-density polyethylene (LLDPE) or high-density polyethylene (HDPE). Developed by DuPont in 1960 and widely licensed. Engineered by Uhde under the name Sclairtech. Nova Chemicals (Alberta) acquired the technology in 1994. 

High-density polyethylene (HDPE) is a commodity chemical that is produced on a very large scale in one of two catalytic processes the Ziegler-Natta and the Phillips process. The latter accounts for about one third of all polyethylene. It uses a catalyst consisting of small amounts of chromium (0.2-1.0 wt% Cr) on a silica support, developed by Hogan and Banks at the Phillips Petroleum Company in the early 1950s [84,85]. 

Mixed C4 olefins (primarily iC4) are isolated from a mixed C olefin and paraffin stream. Two different liquid adsorption high-purity C olefin processes exist the C4 Olex process for producing isobutylene (iCf ) and the Sorbutene process for producing butene-1. Isobutylene has been used in alcohol synthesis and the production of methyl tert-butyl ether (MTBE) and isooctane, both of which improve octane of gasoHne. Commercial 1-butene is used in the manufacture of both hnear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE)., polypropylene, polybutene, butylene oxide and the C4 solvents secondary butyl alcohol (SBA) and methyl ethyl ketone (MEK). While the C4 Olex process has been commercially demonstrated, the Sorbutene process has only been demonstrated on a pilot scale. 

The process developed at CPRR is said to be similar in its layout to those used in private industry. Most plastic reclamation systems are designed to work with rigid containers, such as PET beverage bottles, and HDPE milk or household product containers, because they are currently the easiest postconsumer items to collect and sort. PET beverage bottles are actually not one, but several materials a PET body (clear or green), a pigmented high-density polyethylene (HDPE) base cup, aluminum cap, label, and adhesives. To separate these components, either a dry or wet separation method based on one or more of the different physical properties of the materials can be used. 

Ethylene Polymers. Depending on the polymerization conditions, three major types of polyethylene are manufactured low-density polyethylene (LDPE) by free-radical polymerization, linear low-density polyethylene (LLDPE) by copolymerization of ethylene with terminal olefins, and high-density polyethylene (HDPE) by coordination polymerization. The processes yield polymers with different characteristics (molecular weight, molecular weight distribution, melt index, strength, crystallinity, density, processability). 

High-density polyethylene (HDPE) bottles in multi-serve and single-serve sizes are used for juice drinks that appeal- mainly in the chill cabinet (short shelf-life distribution) section. This is probably more to do with the product process... 

Polyethylene (PE) is the largest synthetic commodity polymer in terms of annual production and is widely used throughout the world in a variety of applications. Based on the density, PE is classified as LDPE at 0.910-0.930g/cm3, high-density polyethylene (HDPE) at 0.931-0.970g/cm3, and linear low-density polyethylene (LLDPE) based on the polymer chain microstructure. At present, processes that produce PE use the following raw materials ... 

Other applications for THV are flexible liners (drop-in liners or bag liners), used in chemical process industries and other industries, and blow-molded containers, where it enhances the resistance to permeation when combined with a less expensive plastic (e.g., high-density polyethylene-HDPE), which provides the structural integrity.61 Optical clarity, excellent weatherability, and flexibility make THV suitable as a protection of solar cell surface in solar modules.63... 

Application To produce high-density polyethylene (HDPE) using the stirred-tank, heavy-diluent Hostalen process. 

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