The main materials of food packaging bags are :PVDC(polyvinylidene chloride), PE(polyethylene), PP (polypropylene), PA(nylon), EVOH(ethylene alcohol copolymer), aluminized film (aluminum +PE) and so on. Film production is divided into stretch film and blow molding film. General composite bag materials include polyethylene (PE), polytene, nylon and polycool. These are the main membranes. Film production is divided into stretch film and blow molding film. Dry goods frozen goods, generally with PET/PE. Such as high temperature cooking, generally with nylon composite CPP, or other composite.
At present, the most important food packaging is PP and PE, that is, polypropylene and polyethylene plastics. Compared with the safety performance, the safety performance can meet the food packaging in the world has not been reported on PP and PE product problems. There has been a heated debate on the issue of bisphenol a on the reproductive development of children. Some countries have banned the use of bisphenol A in food packaging plastics.
Relative to dry non-food packaging, PP and PE plastic additives do not release toxic substances in the process of making the field, such as the previous comparison of XK plasticizer on PVC packaging. The plastic wrap used in the past was PVC, but due to its insecurity, it is now gradually being replaced by PE plastic wrap. PE is soft, mechanical properties are worse than PP, representing products such as shopping bags, plastic wrap, garbage bags, etc. PP is relatively hard, anisotropic (there is a gap easy to open), good mechanical properties, high temperature performance is better than PE, on behalf of bread bags. Generally according to the material structure, the inner layer is PE or CPP, the outer layer is PA, PET, there may be EVOH or PVDC in the middle, and some use aluminum film or aluminum foil reason: PE and CPP heat sealing performance is better, that is, easy to seal. PA, PET printing good, can be used in the outer printing beautiful picture. PVDC and EVOH have good barrier to prevent oxidation. Aluminized film, good shading of aluminum foil, suitable for products that are not easy to see light.
Various materials have different properties and different uses. Generally speaking, food packaging bags are not a single material, but multi-layer composite. Dry and frozen goods generally use PET/PE. Such as high temperature cooking, nylon composite CPP, or other composites are generally used. Ham sausage red casing is a single material of PVDC. Transparent paper /PP, kraft paper /PE/AI/PE, AI/PE, etc., are usually used in candy chocolate.
