Polyethylene or PE is the largest volume commodity thermoplastic and cheapest packaging film. It is used for a wide variety of applications. PE is soft, very flexible, clear, and has good tear and moisture resistance but only fair gas barrier properties. The two most important grades are low density polyethylene(LDPE) and linear low density polyethylene (LLDPE). These two resins are often thought to be the same because they have very similar properties. For example, both have good to fair clarity, excellent chemical resistance, good moisture barrier but poor gas barrier properties. Both types can be heat-sealed and are strong, tough and highly flexible.
APPLICATIONS
Both LDPE and LLDPE films are used for similar applications, including stretch- and shrink-wraps, bags, liners, and packaging films. Both find uses for countless produce and applications including carryout bags, candy wrap, food packaging, trash and can liners, grocery bags, bubble packaging, overwrap and envelope films, industrial liners, shipping sacks, mattress bags, and agricultural and construction film.
ULDPE is often used for very specific film applications, such as stretch wrap and food packaging. Important applications for ULDPE resins and resin blends include heavy-duty sacks, consumer bags, turf bags, mulch films, silage wrap, and packaging for cheese, meat, coffee, and detergents. They are also widely used for injection-molded products such as heating and water pipes.
Due to the low odor, high chemical resistance and inertness, many PE grades are suitable for packaging applications under FDA regulations.