1. There are many kinds of plastics. It's hard to tell if they are harmful. Replacing plastics with ceramics, glass or metal, the answer is the same, maybe, so it's meaningless.
2. Long time and hot water are not quantitative, so be smart and understand it as repeated use of more than three months and boiled water, which is a good contrast, because if used for more than two years, it is recommended to use glass and ceramics, plastic has aging problems;
3. According to the above standards, there are several kinds of plastics that can be used, PP (No. 5), HDPE (No. 2) and TRITAN. Among them, PP is the most common in the food industry, that is, microwave oven-specific plastics. In the normal processing process, they do not contain excessive harmful substances.
4. The main concerns are No. 1 plastic PET and No. 7 plastic PC. The most common type of PET water bottle is the mineral water bottle. It will soften when heated, which seems harmful, but it doesn't matter. The problem of PC is BPA, but if viewed rationally, the real release of BPA will not affect the health of adults, but the existing evidence shows that BPA is harmful to infants and children. It is suggested that infants and young children should use less water bottles made of PC.
5．There is also a kind of PS polystyrene in common plastic, that is, the material of foam lunch box. The beverage cup on the airplane is also generally this kind of material. In theory, it is not suitable for long-term use, because the aging resistance is worse.