Technology Guide

This section introduces Lotte Chemical’s production and processing technology and processes for each plant.


HDPE film molding involves melting thermoplastic resin by an extruder, blowing air into it to make a tube,

cooling it as it passes through the pulling or winding roll, and yielding a product.

■ Process

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HDPE film Molding Device

The HDPE film molding device consists of 4 units: extrusion, blow, pulling, and winding.

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Extrusion Unit

It supplies raw material resin through the hopper of the extruder. The resin supplied within the extruder is transferred to the die/head of the extruder as it is melted by the screw and heated within the extruder. The transferred resin is extruded from the die/head vent in a cylindrical form.

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By opening the valve of the air supply device, it injects air into the resin that is extruded from the extruder in a cylindrical form. Depending on the amount of the injected air, the width and thickness of the molded film varies. More air injection increases the width of the film but reduces its thickness.

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Pulling Unit

Hold the edge of the resin that is swollen from air injection, put it through the stabilizer and insert it into the pulling roll. The width and thickness of the film are adjusted as well by the speed of the pulling roll.

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Winding Unit

Once the thickness and width of the film are fixed, the winding unit winds it to be made into a product. Unlike other molding devices, the HDPE film is cooled by air exposure. There is no need for a separate cooling system since it is thin and its surface has large exposure area to air.