USEON's own technology for PET extrusion

Learn something about PET recycling process

Firstly sorting and grinding must be done, dirty flake passes through a series of sorting and cleaning stages to separate PET from other materials that may be contained on the bottle or from contaminants that might be present. First, regrind material is passed through an “air classifier” which removes materials lighter than the PET such as plastic or paper labels and “fines” -- very small PET particle fragments that are produced during granulating. The flakes are then washed with a special detergent in a “scrubber.” This step removes food residue that might remain on the inside surface of PET bottles and containers, glue that is used to adhere labels to the PET containers, and any dirt that might be present.

Next, the flakes pass through what is known as a “float/sink” classifier. During this process, PET flakes, which are heavier than water, sink in the classifier, while base cups made from high-density polyethylene plastic (HDPE) and caps and rings made from polypropylene plastic (PP), both of which are lighter than water, float to the top. Following the float/sink stage the flakes are thoroughly dried. After they have dried, the PET flakes pass through what is known as an electrostatic separator, which produces a magnetic field to separate PET flakes from any aluminum that might be present as a result of bottle caps and tennis ball can lids and rings. Some recyclers use a number of different particle separation technologies where PET flakes are further processed to remove any residual contaminants that may still be present, such as x-ray separation devices for PVC removal, or optical sorting devices to remove other contaminants. The purity level to which PET flakes are processed depends on the endue applications for which they are intended.

To get the highest value end-uses for recycled PET

Recycled PET is manufactured into numerous products. The five major generic end-use categories for recycled PET plastic are

1) packaging applications (such as new bottles),
2) sheet and film applications (including some thermoforming applications, such as laundry scoops),
3) strapping,
4) engineered resins applications (such as reinforced components for automobiles), and,
5) fiber applications (such as carpets, fabrics and fiberfill).

USEON's best extruders for PET extrusion to protect initrisic viscosity

How to avoid the negative depolymerization processes -- like glycolysis and methanolysis – break down the PET plastic into its individual chemical components, is the most critic requriement to extrude PET virgin chips or clean flakes. Anyway, the key for all possible extruders is the good condition for granules to be plasticated and pumped at high temperature. Since 5 years ago, we have tested co-rotating twin screw extruders, venting single screw extruders, and counter-rotating twin screw extruders. Finally, we got the best one, high speed counter-rotating twin screw extruders. Addionally, with such kind mahcines, strong pumping capacity is easily available to provide possiblity to avoid gear pump in some extrusion process. More details, please approach our TDY-A series extruders.