BOPP (biaxially oriented polypropylene) and CPP (cast polypropylene) are both common polypropylene (PP) materials, and there are some differences in the production process, physical properties and application areas of plastic packaging bags.
1. Packaging bag production process
BOPP: Plastic packaging bags made by biaxial stretching technology, that is, stretched horizontally and longitudinally during the production process, so that they have higher strength and tear resistance.
CPP: Plastic packaging bags are made by casting process, and the production process is not stretched, so the structure is softer and the transparency is higher.
2. Physical properties
BOPP: Plastic packaging bags have high strength, rigidity, transparency and gloss, strong wear resistance and chemical resistance, and are not easy to tear. The surface of BOPP film is suitable for printing, especially for packaging that requires high transparency and glossy effects.
CPP: Soft and has a certain degree of ductility, high transparency, but not as strong and rigid as BOPP. CPP film has good heat resistance, is suitable for heat sealing, and has moisture and oxygen resistance, so it is often used in packaging that requires high heat sealing performance.
3. Application fields
BOPP: usually used for food packaging (such as candy, biscuits, instant noodles, etc.) and various composite film packaging. Due to its excellent gloss and transparency, it is often used as a printing layer or outer packaging layer.
CPP: mostly used for frozen food, retort packaging, pharmaceutical packaging, etc. CPP film has good heat sealing and moisture resistance, and can be used directly as an inner packaging material, suitable for retort bags, vacuum bags, daily cosmetics packaging, etc.
4. Advantages
BOPP advantages: high strength, tear resistance, wear resistance, excellent gloss and transparency.
CPP advantages: good heat sealing performance, high softness, suitable for lamination.
BOPP and CPP materials each have their own applicable scenarios in the plastic packaging industry. BOPP is mainly suitable for packaging that requires high transparency and strength, while CPP is suitable for inner packaging that requires good heat sealing performance.
