From a conceptual perspective:
PC (Polycarbonate) : This is a colorless, transparent plastic that is aesthetically pleasing and smooth. Due to its non-toxic and odorless nature, as well as its excellent UV-blocking and moisture-retaining properties, PC has a wide temperature range. It remains unbreakable at -180°C and can be used long-term at 130°C, making it an ideal material for food packaging.
PET (Polyethylene Terephthalate) : This is a highly crystalline, colorless, and transparent material that is extremely tough. It has a glass-like appearance, is odorless, tasteless, and non-toxic. It is flammable, producing a yellow flame with a blue edge when burned, and has good gas barrier properties.
From the perspective of characteristics and applications:
PC: It has excellent impact resistance and is easy to mold, allowing it to be manufactured into bottles, jars, and various container shapes for packaging liquids such as beverages, alcohol, and milk. The main drawback of PC is its susceptibility to stress cracking. To mitigate this during production, high-purity raw materials are selected, and various processing conditions are strictly controlled. Additionally, using resins with low internal stress, such as small amounts of polyolefins, nylon, or polyester for melt blending, can significantly improve its resistance to stress cracking and water absorption.
PET: It has a low coefficient of expansion and a low molding shrinkage rate of only 0.2%, which is one-tenth that of polyolefins and lower than PVC and nylon, resulting in stable dimensions for the products. Its mechanical strength is considered the best, with expansion properties similar to aluminum. The tensile strength of its films is nine times that of polyethylene and three times that of polycarbonate and nylon, while its impact strength is three to five times that of standard films. Additionally, its films possess moisture barrier and aroma retention properties. However, despite these advantages, polyester films are relatively expensive, difficult to heat seal, and prone to static electricity, which is why they are rarely used alone; they are often combined with resins that have better heat sealability to create composite films.
Therefore, PET bottles produced using a biaxial stretching blow molding process can fully utilize the characteristics of PET, offering good transparency, high surface gloss, and a glass-like appearance, making them the most suitable plastic bottles to replace glass bottles.
Post time: Nov-04-2024