1. From a conceptual perspective:

PC (Polycarbonate): It is a colorless, transparent, smooth and aesthetically pleasing plastic. Due to its non-toxic and odorless properties, as well as its ability to prevent ultraviolet rays from penetrating and maintain moisture and fragrance, PC has a wide temperature resistance range and is not brittle at -180 ℃. It can be used for a long time in an environment of 130 ℃, making it an ideal food packaging material.

PET: A material with good crystallinity, colorless, transparent, and extremely tough properties. It has a glass appearance, odorless, odorless, non-toxic, flammable, and has a yellow flame with a blue edge during combustion, with good airtightness.

2. From the perspective of characteristics and usefulness:

PC: With excellent impact resistance and easy molding, it can be manufactured into bottles, cans, and various forms of containers, used for packaging fluid substances such as beverages, alcohol, milk, etc. The biggest drawback of PC is its stress cracking. In addition to selecting high-purity raw materials and strictly controlling various processing conditions in production, the use of resin modification with low internal stress, such as a small amount of polyolefin, nylon, polyester and other melt blending, can significantly improve stress cracking resistance and water resistance.

PET: has a small expansion coefficient and a low molding shrinkage rate of only 0.2%, which is one tenth of polyolefin and smaller than PVC and nylon. Therefore, the size of the product is stable. The mechanical strength can be considered the best, and its degree of expansion is similar to that of aluminum. The film strength is 9 times that of polyethylene, 3 times that of polycarbonate and nylon, and the impact strength is 3-5 times that of ordinary films. And its film also has moisture-proof and fragrance retention properties. Although polyester has the above advantages, its thin film is expensive, difficult to heat seal, and prone to static electricity, so it is rarely used alone. Most of them are made of composite thin films by coating with resin with good heat sealing properties.

Therefore, PET bottles using the biaxial extension blow molding method can fully utilize the characteristics of PET, which has good transparency, high surface gloss, and a glassy appearance. It is the most suitable plastic bottle to replace glass bottles.