The film material used for the production of retort pouch is the basis for satisfying the cooking conditions. It is usually determined according to the cooking conditions of the high-temperature retort pouch and the characteristics of the contents to determine which substrates, what specifications, the order of combination, which type of ink and glue to use, etc. .
The film substrates of common cooking bag materials are: BOPET, B0PA, HDPE, RCPP, AL, co-extruded EVOH, co-extruded PVDC, co-extruded PE, etc. There are also new five-layer co-extruded films such as PP/AC/EV0H/ AC/PP, PP/AC/PA/EV0H/PA/AC/PP, etc.; in addition, copolymerized nylon MXD6, ceramic vapor-deposited film such as SiOxPET12um, multi-layer co-extruded film and ceramic vapor-deposited film are limited by technical process and price factors. The current application on high temperature cooking bags is still rare.
According to the order of the surface layer (or the printing layer), the barrier layer and the heat sealing layer, the structure of the composite packaging material can be combined, and the single layer material can be used as both the printing layer and the barrier layer, so the packaging bag can be designed as two layers and three according to requirements. Layer, four or more layers, such as: BOPET//RCPP, BOPA//RCPP, BOPET//BOPA//RCPP, BOPET//A1//RCPP, BOPET//A1//BOPA//RCPP, etc.
For the thickness of the substrate, it is usually selected as: BOPET12um, BOPA15um, AL7um or AL9um, RCPP50um, RCPP70um, RCPP80um, RCPP100um, etc. BOPA and AL are usually selected for the barrier layer, and BOPA25um and AL12um are also selected according to actual needs, large capacity and special requirements. The RCPP thickness selected for the high temperature cooking bag also exceeds 100 um. In order to overcome the defects that RCPP is not resistant to falling, the liquid packaging bag generally adds an auxiliary agent to the film to enhance its drop resistance.