The logo on the bottom of Tupperware Cai Ying Cup is No.7. What are the other materials?

There is a triangle with an arrow at the bottom of the plastic bottle. There is a number in the triangle, which represents the material used in the bottle. The number 5 in the triangle is made of PP material, but the bottom of Tupperware Cai Ying water cup is marked with the number 7 of other materials. This material can't be heated, and it is toxic after heating, but the instructions of Tupperware Cai Ying water cup say that it can be heated. Why? Satisfied answer ☆ Love Yao → Eternal Level 3 2010/-13 All plastic products are divided into 7 grades, and 1~3 cannot be recycled. 4~7 are recyclable. 1: disposable beverage bottle 2: disposable plastic bag 3: PVC engineering material 4: PE low density polyethylene 5: PP polypropylene 6: PS polystyrene 7: other kinds -PC, PEI+PET (this is a whole, a patented product specially developed by American General Motors Company, with high temperature resistance 180). The label of Cai Ying Suixin Cup is 7, and the material is PC.