The plastic scrap recycling process starts from the classification. After that, the plastic is cut into small flakes and melted at high temperature to be molded, pelletized and packed finally.
Our whole recycling procedure is:
Plastics for recycling come from two main sources: post consumer plastics and post industrial plastics. Post consumer plastics are those which have already been used by people. These are the plastics collected in plastics recycling bins and at domestic roadside collections. Post industrial plastics, on the other hand, are rejects from industry — offcuts, damaged batches etc. These plastics are collected either directly from the industry or collected by the local council, squashed into bales.
In theory, every type of plastic can be recycled. The incoming plastic is manually sorted by machines or labour forces. It is particularly important that one type of material is removed from the another one, as the more sophisticated sorting used later on cannot differentiate between two types of plastic.
Each sorted stream of plastic is then sent separately to a chipper. This is a cylinder of blades somewhat like an old-fashioned lawnmower in a vessel with a 10 mm grill floor. The blades cut the material until it is small enough to fall through the grill.
The chips are then washed to remove glue, paper labels, dirt and any remnants of the product they once contained. Both the “other” stream and the PET stream are washed at around 90oC for at least twelve minutes, while the HDPE (which has a much lower melting point) must be washed below 40oC to prevent discolouration.
This is done by melting the chips and extruding them out first through a fine grill to remove any solid dirt or metal particles that have made it through the treatment thus far and then through a die of small holes. If the plastic was simply allowed to extrude from these holes it would come out as spaghetti-like strings and quickly tangle together. However, it is sprayed with water as it comes out (to prevent the plastic from sticking together) and cut off by rotating knives to give small, oval pellets.
Recycled pellets can be widely used for making products by extrusion, injection and etc. When plastics are recycled, they are usually used to make a lower quality form of plastic. For example, plastic water bottles cannot be recycled into new plastic water bottles but the resins from them can be used to make fibers for pillows. Other common products that are made from recycled plastics include toys, drainage pipes, tables, car parts, etc.