Most plastics need to be sorted before recycling used plastics by various plastic recycling methods. Due to the complexity and complexity of plastic consumption channels, some post-consumer plastics are difficult to distinguish by simple appearance. Therefore, it is best to indicate the variety of materials on plastic products. China has formulated the GB/T16288-1996 "Recycling Mark for Plastic Packaging Products" with reference to the material variety label proposed and implemented by the American Plastics Association (SPE). Although the above marking method can be used to facilitate sorting, there are still many unmarked in China. The plastic products bring difficulties to the sorting. In order to separate the different varieties of plastics for classification and recycling, we must first grasp the knowledge of identifying different plastics. The following describes the simple identification method of plastics:
By observing the appearance of plastics, it is possible to initially identify a large category of plastic products: thermoplastics, thermosets or elastomers. Generally, thermoplastics have both crystalline and amorphous types. The appearance of the crystalline plastic is translucent, opaque or opaque, and it is transparent only in the state of the film, and the hardness is soft to horny. Amorphous is generally colorless, completely transparent when no additives are added, and hardness is harder than horny rubber (additives such as plasticizers are often added at this time). Thermoset plastics usually contain a fill that is impervious to the material and is transparent if it is free of filler. The elastomer has a rubbery feel and a certain stretch ratio.