The number 1-7 represents a common plastic variety, and its meaning is as follows: 1: PET (polyethylene terephthalate). The container made of this material is a common plastic bottle for soda, also known as "Bot bottle". 2.HDPE (high density polyethylene), containers for detergents, shampoos, bath milk, edible oil, pesticides, etc. Most of them are made of high density polyethylene. Most containers are opaque and feel like wax. 3.PVC (polyvinyl chloride) is mostly used to make water pipes, raincoats, schoolbags, building materials, plastic films, plastic boxes and other utensils. 4.LDPE (low density polyethylene), plastic bags are everywhere, and most of the materials are LDPE. 5: PP (polypropylene) is mostly used to make buckets, trash cans, laundry baskets, baskets, microwave food containers, etc. 6: PS (polystyrene), because of its low water absorption, is mostly used to make building materials, toys, stationery, rollers, and cups and boxes of drinks or disposable tableware in fast food restaurants. 7: Other. PC is the abbreviation of polycarbonate. Since polycarbonate does not belong to the material range of 1-6 mentioned above, the number marked in the middle of the triangle of the periodic sign is 7. At the same time, in order to facilitate the classification of circulation, the material name PC is marked next to the circulation mark.