1. Basic sealed box. Made of polypropylene (PP), the temperature range is -20-+ 120 degrees. The microwave oven can't heat high-fat food for a long time, and it will burn. The same material brand is Tuporware of the United States.
2. Advanced sealed box. The material is polycarbonate (PC), and the temperature resistance range is -40-+ 140 degrees. Transparency is higher than PP, and it is also more resistant to grease.
3. Glass style. The material is boric acid heat-resistant glass. The temperature range is -20-+300 degrees. Grease can be heated in the microwave oven for a long time and put in the oven. But it can't be heated directly with open flame, and it is not resistant to falling.
The * * * nature of Lok Kou is food-grade safety, acid and alkali resistance, good sealing and good price. The disadvantage is not keeping warm (sometimes not keeping warm is also an advantage).
Stainless steel lunch box (here refers to 18/ 10 medical stainless steel. Inferior stainless steel products are not discussed), and the advantages are durability, high grade and better sealing. And the heat preservation effect is excellent (sometimes a disadvantage). Representative brands are Japanese Tiger Brand, Zojirushi and Thermos Bottle. The price is the same.
As for the disadvantages, it is not allowed to use microwave oven to heat, and it is not allowed to store foods with high pH value and high salt content for a long time. The price is also expensive.
For reference.