PE has many uses such as wires, cables, hoses, pipes and profiles. Pipe applications range from small cross-section yellow pipes for natural gas to thick wall black pipes with a diameter of 48in for industrial and urban pipelines. Large diameter hollow wall pipe is growing rapidly as a replacement for concrete storm drains and other sewer lines. Sheets and Thermoforming: The thermoformed liners of many large picnic coolers are made of PE, which offers toughness, light weight, and durability. Other sheet and thermoformed products include fenders, tank liners, pan guards, shipping boxes and tanks. A large and rapidly growing sheet application is mulch or pool bottoms, which are based on MDPE's toughness, chemical resistance and impermeability.
Blow molding is commonly used to create smaller containers (less than 16oz) for packaging pharmaceuticals, shampoos and cosmetics. An advantage of this process is that the produced bottles are automatically trimmed without the need for post-finishing steps as in general blow molding processes. Medium to wide MWD grades are generally used, although some narrow MWD grades are used to improve surface finish. HDPE has countless applications, ranging from reusable thin-walled beverage cups to 5-gsl cans, and consumes 1/5 of the HDPE produced domestically. Injection molding grades generally have a melt index of 5 to 10, and there are lower fluidity grades with toughness and higher fluidity grades with machinability. Uses include thin-walled commodity and food packaging; tough, durable food and paint cans; high resistance to environmental stress cracking applications such as small engine fuel tanks and 90-gal trash cans. PE film processing generally uses ordinary blown film processing or flat extrusion processing. Most PEs are used for films, general purpose low density PE (LDPE) or linear low density PE (LLDPE) are available. HDPE film grades are generally used where superior stretchability and excellent barrier properties are required. For example, HDPE film is commonly used in merchandise bags, grocery bags and food packaging.
