Co Extrusion Films

What is coextruded multilayer film?

Co-extruded multilayer films with excellent inner surface cleanliness and pinhole resistance

Co-extruded multilayer films are made of melting multiple resins with different properties by layering them in a mold to form a single film.By designing the resin type and composition ratio, various functions can be added to a single film, such as heat sealability, flexibility, heat resistance, cold resistance, pinhole resistance, and gas barrier properties, according to the customer's required performance.

Advantages of Manufacturing with Co-Extruded Multilayer Films

In co-extrusion blown film production, the inner surface does not come into contact with the outside air, resulting in an aseptic and hygienic film. This is why it is widely used in the medical and food industries.

Transparency
Moisture Resistance
Waterproofing
Chemical Resistance
Oil Resistance
Cold Resistance
Oxygen Barrier
Aroma Retention
Odor Prevention

Flexible and Pinhole-Resistant Films

Friction pinholes, caused by contact between bag folds and cardboard surface, can cause air leakage and liquid spills, contaminating the contents and surrounding area.Co-extruded multilayer film is a non-oriented, flexible film that is less prone to folding and has fewer "friction pinholes". This is a key advantage of this type of film.

Advantages of manufacturing with coextruded multilayer films

Co-extruded multilayer films offer the advantage of tailor-made functionality for diverse applications.While lamination involves bonding films of standard thickness, making it challenging to adjust the ratio of specific layers, co-extrusion technology enables precise control over layer ratios. This versatility allows for the creation of films with precisely tuned properties to meet the specific requirements of various industries.In the food packaging sector, co-extruded multilayer films deliver essential properties such as safety and gas barrier performance. For medical applications, safety, heat resistance, and strength are prioritized. And in the electronics industry, anti-static properties and cleanliness are crucial.The ability to seamlessly integrate these diverse functionalities into a single film is a key strength that has earned co-extruded multilayer films widespread recognition and continued support across a broad range of industries.

Multi-layer film produced with minimal labor and low impact on the environment

Laminated multilayer films are made by first extruding raw materials into a base film (single-layer film). These base films are then laminated together with adhesive in a laminating plant. Co-extrusion, on the other hand, is a more environmentally friendly process that produces multilayer films in one step from raw materials, without the need for a base film. This eliminates the use of adhesives and the associated organic solvents, which can remain in the film.

Comparison of Co-extruded Multilayer Films and Laminated Multilayer Films

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Co-extruded multilayer films

Multilayer films are formed from multiple raw materials using extruders, resulting in a simpler manufacturing process compared to laminated multilayer films

Laminated multilayer films

Molding method: The raw material pellets are melted and layered in the mold in a one-step process.; Manufacture by laminating two or more films (substrates) using adhesive.
Features: Non-oriented film is soft and flexible with excellent pinhole resistance.; Color photo printing is possible.
Advantage: The resin and layer ratios can be easily adjusted to meet specific needs.; Layering of metals such as aluminum foil and paper is also possible.

Disadvantages of Co-extruded Multilayer Films

Mold design is complex due to the simultaneous extrusion of multiple resins.
Advanced molding techniques are required to adjust thickness and layer ratios.
There are limitations to film printing. Color photo printing is difficult, and the production process results in "surface printing" (printing on top of the film).

Co-extrusion multilayer film manufacturing process

Co-extruded multilayer film is a type of film created through extrusion molding. It's made by melting two or more types of plastic and joining them in a mold to form a multilayer structure.Extrusion molding is a continuous process where molten plastic is forced through a mold, shaping it into a desired cross-section. It consists of three steps: melting the raw material → extruding it from the mold → cooling and solidifying. "Co-extrusion" refers specifically to the use of two or more extruders (machines that melt plastic) to create multilayer films in a single mold.

Three types of coextrusion multilayer film manufacturing methods

Water-Cooling blown film method

This manufacturing method involves extruding a tube and then rapidly cooling it with water. This rapid cooling process produces a transparent film. Additionally, the inside of the tube is not exposed to air until it is used by the customer, ensuring exceptional hygiene. This method is primarily used for packaging food and medical products.
Air-Cooling blown film method

This method involves cooling extruded tubes with air. It is used in applications where cleanliness is crucial, such as for displays, semiconductors, and electronic components.
T-die method

This method involves cooling extruded film with cooling rolls to produce sheet-shaped film. This film is used for food and medical container packaging.