Cast CPP film

Application of CPP film for food packaging
January 4th Plastic Material Technology
CPP is a polypropylene (PP) film produced by a cast extrusion process in the plastics industry. This type of film is a non-oriented film unlike BOPP (bidirectional polypropylene) film. Strictly speaking, the CPP film has only a certain orientation in the machine direction (MD) direction, mainly due to the nature of the process. Excellent clarity and finish are formed on the film by rapid cooling on the chill roll.

(1) The main characteristics of CPP film include:

- Lower cost and higher output compared to other films such as LLDPE, LDPE, HDPE, PET, and PVC.

- Higher stiffness than PE film.

- Excellent moisture and odor barrier.

- Multi-functional, can be used as a base film for composite materials.

- Metallization is possible.

- As a food and commodity packaging and packaging, with excellent demonstration, the product is still clearly visible under the packaging.

Although some PP films are produced by a casting process for use in the sanitary field or as synthetic papers containing fillers and other additives, the term CPP film generally refers to high definition films suitable for applications such as lamination, metallization and packaging. .

(2) Current use and potential use

Current uses for CPP include: garment, knitwear and flower bags; pouches; outer packaging; documents and photo albums; food packaging; and metallized films for barrier packaging and decoration.

Potential uses include: blister packaging (instead of PVC); food packaging; candy packaging (twisted film); pharmaceutical packaging (infusion bag); replacing PVC in areas such as photo albums, folders and documents; synthetic paper; Report cover; business card holder; ring folder and standing bag composite.

CPP films are so attractive because of their low cost and price advantages over materials such as PET, LLDPE, and LDPE. Compared to LLDPE, a 5% to 10% spread plus a 2% density difference is attractive. Furthermore, due to the inherent rapid cooling properties of the cast film, excellent finish and transparency can be formed. This feature makes PP film the material of choice for packaging applications requiring high definition. It provides a transparent window that makes the contents clearly visible, making it ideal for the flexible packaging market. After corona treatment, it is easy to print using various processes. This special feature improves the final appearance of the film.

CPP is excellent in heat resistance. Since the PP softening point is about 140 ° C, such films can be used in the fields of hot filling, retort pouch, aseptic packaging and the like. Plus acid, sputum and grease resistance make it the material of choice for bread packaging or laminates. Its food contact safety, excellent performance, will not affect the flavor of the food, and can choose different grades of resin to obtain the desired characteristics.

(3) Market size

According to CMAI estimates, the global demand for thermoplastics in 2001 was 135.7 million tons, and PP accounted for 22% of total polymer use. Western Europe, North America and Asia are major consumers of polypropylene, accounting for 78% of global demand. Among them, only Japan, Southeast Asia, China and South Korea accounted for 39% of the total global PP demand.

According to the US market research firm Freedonia Group, as of 2002, the total demand for PP film in the United States was about 4.5%, an average annual growth rate of 671,500 tons. However, most of the above films belong to the BOPP film. Food packaging is expected to account for 85% of this demand. In the United States, CPP film is not as popular as other regions, but it has recently begun to expand its use in the field of laminates. According to Borealis figures, the Western European PP market is expected to reach 8.1 million tons. The market size of CPP film in 2003 is expected to reach 423,000 tons, the main application areas are laminates and food packaging.

Cast PP films, especially metal grades, are highly advantageous in the Asian food packaging market. For example, in 1997, the amount of CPP film in Japan was as high as 120,000 tons.

In Latin America, CPP film is also beginning to be favored by the market and used more and more widely. According to the Freedonia Group, packaging PP is around 400,000 tons.
For the future, the development trend of CPP film will be:

- Market share growth, PVC, PS and PE market share declines;

- A large number of co-extrusion structures are used in demanding applications;

- improved sealing characteristics;

- Processing problems such as fouling are resolved;

- Increased productivity in areas such as film production, auxiliary operations and end use;

- enhanced metal adhesion;

- PP increases market share in non-traditional markets such as desserts, salads, canned foods, fruit purees, snacks, candy pouches, peeling structures, and kink films;

- In the field of packaging, such as bread, biscuits, pasta products, snacks, etc., as a low-cost alternative to BOPP film.

2 organic antibacterial film

1 antibacterial mechanism

The main mechanism of action of organic antibacterial agents is to gradually enter the cells by binding to the surface of the microbial cell membrane, or react with groups such as sulfhydryl groups on the cell surface to destroy the synthesis system of proteins and cell membranes and inhibit the proliferation of microorganisms.

Application of organic antibacterial film

At present, TBZ (2-benzimidazole) produced by American Mike, OBPA (10,10, oxydiphenol oxime) produced by AkcrosChemical, and IRGAGUARD produced by Ciba are all certified by the US FDA for food. The packaged organic antibacterial agent can be added to the resin to form a food antibacterial packaging film.

3 catalytic catalytic inorganic antibacterial film