In all areas of our daily life and agricultural production, plastic products are ubiquitous, and when these products reach the end of life or purpose of use, they are discarded and become waste plastic. Of course, the source of used plastics is not limited to this. As stated in the Waste Recyclers Network, wastes or waste products will be generated at each stage of plastics synthesis, molding, circulation, and consumption. Its specific sources mainly include the following aspects.
Resin generated during resin production generates waste in the following three aspects:<1>1. The attached material (commonly known as "rice pan") scraped off the inner wall of the reactor during the polymerization process. And failed material.
2. During the compounding process, the extruder's cleaning waste and unqualified compounding materials.
3. Falling material (dumping material) and slag removal during transportation and storage. The amount of waste depends on the complexity of the polymerization reaction, the number of manufacturing processes, the production equipment, and the proficiency of the operation. In all types of resin production, polyethylene produces the least waste, and PVC produces the most waste.
In the molding process, various types of waste products, external products and scraps are generated in various molding processes of thermoplastics. Such as six injection molding cold materials, sprue cold solid material, cleaning machine waste, waste edge, etc.; in the molding machine cleaning waste, trimming material and the end product on the cut off material; blow molding process Blanking mouth on blow molding machine, cold solid material and cleaning waste in equipment, and flashing of hollow container, etc. (The production rate of the worn-out waste of the bottle can reach up to %40); from the mixing machine during calendering , Falling scraps, trimmings, and waste products from calenders; spigots, edgings, and scraps from moulding counties in rotational molding. The amount of waste generated in the molding process depends on the processing technology, molds, and equipment. In general, this waste recycling rate is relatively high. They have a clear variety, a clear amount of fillers, and a small amount of pollution in Chengdu. The performance is close to that of the original materials, and the pretreatment work is small. Usually, they are only used for comminution. They can be used as a back-up material for incorporation into new materials, as well as performance and quality of products. Less affected. Thermosetting plastics also generate waste products and wastes during molding. If cross-linking reactions occur in waste products, the recycling of these waste products is very difficult. The waste generated during compounding and reprocessing is only a small part of all used plastics. The waste generated during the compounding and reprocessing process is the waste that is removed when the compounding equipment is unloaded and it is not properly operated. In the case of defective products, most of them are recyclable waste plastics.
Secondary processing in secondary processing is usually a transfer of a semi-finished plastic product purchased from a molding plant (to the effect that the toner image formed on the drumhead is transferred to paper). The process is called transfer), sealing, thermoforming, machining, etc. The finished waste is often more difficult to handle than the waste generated by the molding plant. For example, the waste after processing such as printing and electroplating should be processed. The difficulty and cost of taking out the printing layer and the plating layer are very large, and the direct retrieving or pelletizing to obtain the reclaimed material is of much lower value. The waste edges and waste particles generated by thermoforming and mechanical cutting processes are relatively easy to recycle and recycle, and the value of the recovered waste materials is also relatively high.
After consumption, this type of waste plastics has a wide range of sources and is complex to use. It must be treated before it can be recycled. Such wastes include: (1) Bags, barrels, etc. used in the chemical industry. (2) Containers, rayon filaments, etc. in the textile industry.
(3) Packaging materials, foam cushions, etc. in the household appliance industry.
(4) Construction materials, pipe materials, etc. in the construction industry.
(5) Shrink film, stretched film, etc. in the canning industry.
(6) Turnover boxes, egg trays, etc. in food processing.
(7) Agricultural plastic film, greenhouse film, chemical fertilizer bag and so on.
(8) Fishing nets, floats, etc. in the fishery.

(9) Bumpers, fuel tanks, battery boxes, etc. removed from scrapped vehicles.
Produced in municipal solid waste This type of waste plastic also belongs to post-consumer plastics. Due to its large quantity and difficulties in recycling, it poses a serious threat to the environment and is the focus of future recycling work. class. In China's urban domestic waste, waste plastics account for more than 2% to 4%, most of which are disposable packaging materials. They are basically polyethylene (PE), polypropylene (PP), polystyrene (PS), and poly. Vinyl chloride (PVC), polyethylene terephthalate (PET), etc. Among these waste plastics, polyolefin (PO) accounts for %70.
There are many kinds of used plastic products in domestic garbage. They include various packaging products such as bottles, films and cans; daily products such as barrels, pots, cups, plates, etc.; toy accessories and entertainment articles. , Clothing and footwear, tying ropes, packing belts, woven bags, health care products, etc.