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Continuous Type EPS Pre Expander extrusion foaming process

Views: 2     Author: Site Editor     Publish Time: 2022-09-29      Origin: Site

Continuous Type EPS Pre Expander is widely used in various instruments and packaging blocks for various light industrial products, most of which are made of compressed EPS foam. It can be formed directly into the shape corresponding to the packaging and has reliable shock, heat, and pressure resistance. There are other characteristics. The molding process of EPS plastic packaging pads can be carried out on a hydraulic press.


When the mold drives the cylinder of hydraulic press to close the mold, low speed, high speed, low speed off to start work, the mold closed with a gap, locked by adjusting the cylinder. When feeding, first open the exhaust port and blow the mold cavity with air. After preheating the mold cavity with 0.1-0.2 MPa steam for 30 seconds, feed the EPS into the mold cavity with the feed gun. The charged air is discharged through the air vent and the gap left by the closed mold. After feeding, the mold is closed, and the air chamber is heated with 0.1-0.2 MPa steam for 10-30 minutes.

EPS Pre Expander

EPS expansion fills the mold cavity. Cooling water is sprayed into the mold wall for cooling, then the product is demolded and sent to the drying chamber, where it is dried in hot air at 50-60°C for 24 hours to cure the mold.


The foamed plastic paper or sheet has a fine pore structure and glossy surface, light and soft, with heat insulation and water resistance: it can be used as decorative material; it can be made into trays, cups, and various types of containers, snack boxes, etc. by vacuum forming Continuous Type EPS Pre Expander is formulated so that the extruded foamed paper or sheet has fine pore structure with The nucleating agent can be uniformly distributed in EPS in powder form. On the bead surface, to avoid interaction, oily substances such as liquid paraffin, silicone oil, or dioctyl phthalate are usually added, or stearic acid, starch, and other powdery substances are added to separate them. In addition, various additives can be added; dyes can also be added to obtain different colors of foamed paper or sheets.


Continuous Type EPS Pre Expander in the molding process, the prepared material is added to the bin and extruded continuously by the extruder screw. The foam is continuously extruded from the head die and blown into a cylindrical shape. The extruder is usually a single-screw extruder, and the compression ratio should be controlled appropriately, not too big or too small. Too large will make the foaming agent escape from the funnel. Too small will produce bubbles because the pressure of the blowing agent in the barrel is too small; the gap between the screw and the barrel should be small; the head screw shape, which can improve the mixing effect, prevent the flow of materials, and fast traction speed. The extruded foam is cooled under blowing wind, so the polystyrene macromolecules are oriented along the channel, and the ionic direction improves the mechanical strength of the product.


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