Why does saran wrap have better stretch than grocery bag?
Saran resins for food contact can be extruded, coextruded or coated by a processor to meet specific packaging needs. About 85 percent of PVDC is used as a thin layer between cellophane, paper and plastic packaging to improve barrier performance. For non-food contact, Saran resins can be used for molding and melt adhesive bonding. In combination with polyolefins, polystyrene and other polymers, Saran can be coextruded into multilayer sheets, films and tubes. Plastic bags are made of polyethylene. Many kinds of polyethylene can be made from ethylene. Plastic bags typically are made from one of three basic types: high-density polyethylene (HDPE), low-density polyethylene (LDPE), or linear low-density polyethylene (LLDPE). Those thick, glossy shopping bags from the mall are LLDPE, while grocery bags are HDPE, and garment bags from the dry cleaner are LDPE. The major difference between these three materials is the degree of branching of the polymer chain. HDPE and LLDPE are composed of line
