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Laminated Films: These are multi-layer films created by extruding one type of material onto an already formed film or by bonding different types of pre-formed films together using adhesives.

Co-extruded Films: While they share most characteristics with laminated films, the key difference is that all the layers in co-extruded films are extruded and formed simultaneously, with the layers bonded together through heat without the need for adhesives.

Under certain conditions, laminated films can delaminate, but co-extruded films do not, leading to different behaviors under tensile stress. Additionally, because co-extruded films are bonded through heat, squeezing them forcefully can create bubble-like formations, whereas laminated films, bonded with adhesives, do not produce such bubbles when squeezed.

Performance Differences:

1. Laminated films have a wider range of applications. If you need aluminum foil packaging or paper-plastic packaging, laminated films are the only choice. Laminated films can basically achieve functional and personalized packaging, meeting the requirements for shelf life, processing performance, transportation, and storage of the contents.

2. Co-extruded films are commonly used in pure milk bags, courier bags, and metal protective films. A type of co-extruded black-and-white film is often used for courier bags or milk bags. Since courier bags may contain hard objects or face various stresses, regular PE films are unsuitable, making co-extruded films the better choice. For milk bags, co-extruded films must meet food safety standards and be resistant to tearing.

Now, let’s talk about what laminated and co-extruded mean:

The lamination process was the earliest method for making vacuum bags, where adhesives are used to bond the layers. The type of adhesive varies; it could be imported or locally produced in regions like Zhejiang, China. During the cooking process, the adhesive might become visible, although this was a characteristic of earlier methods. The process has since matured, making this issue almost unnoticeable.

Consumer Feel: Laminated films feel hard and thick to the touch.

The co-extrusion process doesn’t use adhesives; instead, the bag is directly produced by compressing multiple layers, usually seven.

Consumer Feel: Co-extruded films feel soft, thin, and flexible.

Fun Fact: The softer the material, the stronger its toughness.