CPP film is cast polypropylene film, also known as unoriented polypropylene film. Depending on the application, it can be divided into ordinary CPP film, aluminized CPP film and steaming grade CPP film.CPP film is a polypropylene film produced in the plastics industry by the cast extrusion process. This film, unlike BOPP (bi-oriented polypropylene) film, is a non-oriented film. Strictly speaking, CPP films are only somewhat oriented in the machine direction (MD) direction, mainly due to the nature of the process. Good transparency and smoothness are developed in the film by rapid cooling on cold casting rolls.
CPP Film Production Process
CPP film is an undrawn polypropylene film made by casting method. At present, China’s CPP film after decades of accumulation, there has been a significant development, compared with the developed countries, the domestic CPP film no matter in the production process and its production equipment have reached the international advanced level.
The production process of cast film generally adopts T-shaped die head method, which is characterized by:
(1) The cast method eliminates the blown film stage of tube film method, easy to drive and less waste;
(2) cast method of production, the chemical molecules arranged in an orderly manner, so it is conducive to improve the transparency of the film, gloss and thickness uniformity, suitable for high-level packaging;
(3) The flow extension part adopts electric up and down swinging and forward and backward moving structure, which is easy to operate;
(4) The corona part adopts air-cooled and water-cooled methods, and the products are not easy to be deformed.
The extruder first melts the raw material resin, and the molten resin is rapidly cooled into a film by the machine head flow extension to the cooling roller with smooth surface. After thickness measurement, haul-off, corona treatment, and spreading, the thicker edge material is cut off, and then it is unfolded and wound up again as a film roll.
Main characteristics of CPP films
Lower cost and higher yield than other films such as LLDPE, LDPE, HDPE, PET, PVG, etc;
Higher stiffness than PE films;
Excellent moisture and odor barrier properties;
Multi-functional, can be used as a composite base film;
Can be metallized;
Excellent demonstration as packaging and overwrap for food and daily necessities, where the product can still be clearly seen under the packaging.
Application of CPP film
1. Laminating film industry: mainly used for clothing, knitwear and flower bags, documents and albums film, food packaging;
2. Aluminized film industry: mainly used for barrier packaging and decorative metallized film. After vacuum aluminizing, it can be compounded with BOPP, BOPA and other substrates and used for high-grade packaging of tea, deep-fried crispy food, cookies and so on;
3. Cooking film industry: mainly used in hot filling, cooking bags, aseptic packaging and other fields;
4. Specialty film industry: mainly used in food outer packaging, candy outer packaging (twisted film), pharmaceutical packaging (infusion bags), in the albums, folders and documents in the field instead of PVC, synthetic paper, self-adhesive tapes, business card holders, circular folders and stand-up pouches composite materials.
Conclusion
CPP film is a kind of functional film with excellent performance and wide range of applications, which has a broad development prospect.
#CPP film #Cast polypropylene film