There are many kinds of food packaging bags used for food packaging. They have their own unique properties and characteristics. Today, we will discuss some common knowledge about food packaging bags for your reference. So what is a food packaging bag? Food packaging bags generally refer to sheet plastics with a thickness of less than 0.25mm as film. Flexible packaging made of plastic film is widely used in the food industry. There are various kinds of food packaging bags. They are transparent, flexible, with good water resistance, moisture resistance and gas resistance, good mechanical strength, stable chemical properties, oil resistance, easy to fine print, and can be heat sealed for bag making. And the commonly used food flexible packaging is usually composed of two or more layers of different films, which can be generally divided into outer layer, middle layer and inner layer according to the location.  

What are the requirements of the commonly used flexible food packaging film on the performance of each layer. First of all, the outer film is generally printable, scratch resistant and media resistant, and commonly used materials include PA, PET, OPP, coating film, etc. The middle layer film should generally have the functions of blocking, shading, physical protection, etc. The commonly used materials are PA, EVOH, VMPET, AL, etc. Then there is the inner film, which generally has the functions of barrier, sealing, anti medium, etc. The commonly used materials are CPP, PE, etc. In addition, some materials have the combined effect of outer layer and intermediate layer. For example, PA can be used as the outer inner seal and also as the intermediate layer to play a certain role in blocking and physical protection.