No. 1 PET (polyethylene terephthalate): mineral water bottles, carbonated beverage bottles. Heat-resistant to 70 ° C, only suitable for warm or frozen drinks, easy to deform when loaded with high-temperature liquid or heated, which is harmful to human body substance dissolves.
No. 2 HDPE (High Density Polyethylene): Cleaning supplies, bath products. Can be reused after careful cleaning, but these containers usually have a small mouth and are not easy to clean.
No. 3 PVC (polyvinyl chloride): It is rarely used in food packaging at present, and it is easy to produce harmful substances at high temperatures.
No. 4 LDPE (low density polyethylene): cling film, plastic film, etc. Heat resistance is not strong, usually qualified PE plastic wrap will appear hot melt when the temperature exceeds 110 ℃. Therefore, when food is put into the microwave oven, the plastic wrap must be removed first.
No. 5 PP (Polypropylene): The only plastic box that can be placed in the microwave.
No. 6 PS (polystyrene): bowls of instant noodle boxes, fast food boxes. They are heat-resistant and cold-resistant, but cannot be placed in microwave ovens, and cannot be used to hold strong acids and strong alkaline substances, so try to avoid fast food Boxes pack piping hot food.
No. 7 PC (other categories): kettle, water cup, feeding bottle. A widely used material, especially for baby bottles, is controversial because it contains bisphenol A. Do not heat it when using it, and do not expose it to direct sunlight.

Commonly used food grade plastics are:
1. PET plastic is often used to make plastic boxes, beverage bottles and other products. The transparent fruit boxes and cake boxes that people often buy are packaging products made of PET sheets and are food-grade safe plastic materials.
2. PP plastic is one of the common plastics. It can be made into any plastic packaging for food, such as special plastic bags for food, plastic boxes for food, straws for food, etc. It is safe, non-toxic and has good low temperature and high temperature resistance. PP is the only plastic that can be heated in a microwave oven, and has high-strength and folding resistance. Food-grade PP sheets are commonly used in quick-frozen dumplings and microwave-heated food packaging.
3. HDPE plastic is commonly known as high-density polyethylene, which has higher operating temperature, hardness, mechanical strength and chemical resistance. It is a non-toxic and safe material and is often used in the production of plastic food containers.
4. LDPE plastic is commonly known as low density polyethylene. The products made of it have the characteristics of tasteless, odorless, non-toxic and dull surface. Commonly used in plastic parts for food, composite film for food packaging, food cling film, medicine, pharmaceutical plastic packaging, etc.
5. PS is often used to make bowl instant noodle boxes, fast food boxes, disposable food packaging boxes, etc., and has good cold resistance. Food grade PS sheets are commonly used in containers such as yogurt cups.
6. PC plastic can be used to make sports water cups, bottles, etc. It is widely used in the production of plastic containers and is a safe material.