The original cup was just a plastic tube. During blowing, one end needs a point to fix the pipe. When the compression is completed, the fixed point remains on it and becomes a stubble.
When a plastic cup is filled with hot water, the cup expands, and so does the bottom. Small depressions can relieve and absorb thermal expansion, so that the bottom will not bulge and the cup can be balanced when placed on a flat surface.
Extended data:
Classification of plastic cups:
1, serial number: "01"PET (polyethylene terephthalate)
Uses: bottles of pure water, mineral water and carbonated drinks.
Features: Can't hold hot water, heat resistant to 70℃, disposable.
It is easy to deform when it exceeds 70℃, and DEHP may be released after it is used for more than 10 months. Can't be exposed in the car; Don't pack alcohol, oil and other substances.
2. Serial number: "02" HDPE (high density polyethylene)
Uses: cleaning containers and supermarket packaging bags for products and bath products.
Characteristics: Heat resistance is 1 10℃. The contained non-food substances can be reused.
Most containers are opaque and feel like wax. It is easy to remain after cleaning and cannot be used as a cup or other liquid.
3. Serial number: "03" PVC (polyvinyl chloride)
Uses: mostly used in water pipes, raincoats, building materials, plastic boxes and other utensils; It is rarely used in food packaging.
Features: when packaging food, it is forbidden to use high temperature and grease, and it cannot be used when heated.
Excellent plasticity, low price, heat resistance of 865438 0℃, rarely used in food packaging. It is difficult to clean and easy to remain, so it cannot be reused.