Contents Olefins Process Aromatics Process Polymer Process 2008013426 Lee Tae Ho

Olefins Olefin Process Olefin is a chain-type unsaturated hydrocarbon that has one or more double bonds within a molecule. Olefin is manufactured through the process of pyrolyzing naphtha, the key ingredient, in a naphtha-cracking facility, and then separating and extracting it.

Aromatic Aromatic Process Aromatics is a collective term for hydrocarbon compounds that hold an hexagonal loop-type molecular structure, such as benzene, toluene and xylene. Aromatics are manufactured by converting TPG(treated pyrolysis gasoline) and heart-cut naphtha, the byproducts of the naphtha cracker, into reformates that possess a number of aromatic properties. Then the aromatics are extracted in liquid form from the reformates at the aromatics extraction process.

Polymer Injection Molding Process The cycle begins when the mold closes, followed by the injection of the polymer into the mold cavity. Once the cavity is filled, a holding pressure is maintained to compensate for material shrinkage. In the next step, the screw turns, feeding the next shot to the front screw. This causes the screw to retract as the next shot is prepared. Once the part is sufficiently cool, the mold opens and the part is ejected.

Polymer Extrusion Molding Process The process begins by heating the stock material (for hot or warm extrusion). It is then loaded into the container in the press. A dummy block is placed behind it where the ram then presses on the material to push it out of the die. Afterward the extrusion is stretched in order to straighten it. If better properties are required then it may be heat treated or cold worked.

Polymer The film blowing Process A single screw extruder is used to melt the polymer and pump it into a tubular die, as shown in cross-section at right. Air is blown into the center of the extruded tube and causes it to expand in the radial direction. Extension of the melt in both the radial and down-stream direction stops at the freeze line (frost line) due to crystallization of the melt. The nip rolls collect the film, as well as sealing the top of the bubble to maintain the air pressure inside. This process is used extensively with polyethylene and polypropylene.

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