Ⅰ. Performance advantages:
1. Good mechanical properties: PET sheets have excellent toughness, high strength, and impact resistance. Their impact strength is 3-5 times that of other films, and they are very fold-resistant. In contrast, the toughness and impact resistance of PVC sheets are relatively weak.
2. High transparency and gloss: PET sheets have extremely high transparency, can block ultraviolet rays, and have good gloss, which can well display the items in the package and enhance the visual appeal of the product. Although PVC sheets also have a certain degree of transparency, they are usually not as good as PET sheets in terms of transparency and gloss.
3. Excellent barrier properties: It has good barrier properties against oxygen, water vapor, and various odors, which can effectively protect the items in the package and extend their shelf life. For example, food packaging can better maintain the freshness and flavor of food, while the barrier properties of PVC sheets are relatively poor.
4. Good chemical resistance: PET sheets can withstand the erosion of a variety of chemical substances, and are not easy to react chemically with the items in the package, ensuring the stability and safety of the package. PVC sheets also have good chemical resistance, but may not be as stable as PET sheets in certain specific chemical environments.
5. Non-toxic, odorless, hygienic, and safe: PET sheets are non-toxic, have reliable hygienic properties, and can be directly used for packaging food, drugs, and medical equipment, which is harmless to human health. However, some additives, such as plasticizers, may be added to PVC sheets during processing. If these additives migrate to the items in the package, they may pose potential risks to human health.

Ⅱ. Environmental advantages:
1. Recyclable and reusable: PET sheets are environmentally friendly materials. After being discarded, they can be recycled and reprocessed to achieve resource recycling and reduce environmental pollution and waste of resources. In contrast, the recycling of PVC sheets is more difficult, and some harmful substances may be produced during the recycling process.
2. No harmful gases are produced during combustion: PET sheets are easy to burn, and no harmful gases such as chlorine produced when PVC is burned are produced during combustion, which is more environmentally friendly.

III. Processing advantages:
1. Excellent surface decoration performance: PET sheets can be printed without surface treatment, are easy to emboss patterns, easy to metalize (such as vacuum metallization), can meet various complex packaging design and decoration requirements, and provide more creative and personalized options for product packaging. PVC sheets also have good surface decoration performance, but in some special decorative process applications, they may not be as convenient and diverse as PET sheets.
2. High melting point: Although this feature may bring certain difficulties in some processing links, such as high-frequency packaging, from another perspective, the high melting point also makes PET sheets have better stability in high-temperature environments, not easy to deform or soften, and can ensure the integrity and beauty of the packaging.

However, PET sheets are not perfect, and their prices are relatively high, which may increase packaging costs. However, considering its advantages in performance, environmental protection, and processing, PET sheets are often more popular in areas with high packaging requirements, such as packaging of high-end food, medicine, cosmetics, electronics, and other products, and gradually stand out in the packaging field and become an ideal packaging material. PVC sheets are still used in some fields where packaging requirements are not particularly high, such as some low-end daily necessities packaging and temporary packaging, due to their low cost, high transparency, and easy molding.