What is the difference between PET and PP plastic bottles

Information summary

There are many materials of plastic bottles, and the functions and characteristics of plastic bottles of different materials are also different. Let's make a comparison between PET plastic bottles and PP plastic bottles.

Polypropylene (PP) is used in microwave oven tableware, basins, plastic barrels, thermos shells, woven bags, etc. Features High chemical stability, good hygiene performance, and high heat resistance. Microwave tableware can be made of plastic products marked with PP. Toxic and non-toxic, harmless to human body. The polymer can have three three-dimensional structures: isotactic, syndiotactic and atactic polypropylene, the former two can be crystallized, the latter cannot. Commercially available polypropylene products basically have an isotactic structure, melting point ~ degrees Celsius, density of crystalline part. g/cm3, non-clean part. g/cm3. The biggest disadvantage of PP is that it is easy to oxidize and age. Now it is overcome by adding antioxidants and ultraviolet light absorbers.

Polyester (PET) application plastic cosmetic bottles, medicine bottles, cosmetic bottles, oil bottles and various bottle caps and thermal insulation caps. The characteristics are good transparency, not easy to break, good chemical stability, suitable for a variety of liquid or solid medicine packaging. It has good shielding properties to ultraviolet rays. Toxic and non-toxic.

PET plastic bottles are the mainstream of cosmetic packaging. The leading position in China's cosmetic packaging industry should be PET plastic bottles. So far, no better or better packaging material has been found to replace PET plastic bottles. PP bottles are mainly molded by one-step injection stretch-blow molding and two-step heating stretch-blow molding machines. The PP bottles have the advantages of transparency, robustness, heat resistance, and low cost.

PP plastic bottles have better high temperature resistance, sensitive bottle shape description, inferior safety, hygiene, and taste persistence of the contents. The price is cheaper than PET, PS, PE and other materials. The scale of use of PP plastic bottles in the cosmetics packaging market has gradually approached PET bottles. The continuous development of modified resins, antireflection agents, and mechanical equipment skills have enabled PP containers to replace glass, PET and PVC containers.