Rigidity and tensile strength of the HDPE resins are considerably higher than those properties in the low and medium density materials. Impact strength is slightly lower, as is to be expected in a stiffer material, but values are high, especially at low temperatures, compared to those of many other thermoplastics.

HDPE resins are available with broad, intermediate, and narrow molecular-weight distribution, which provides a selection to the processor to meet specific performance requirements. As with the other polyethylene grades, very high molecular weight copolymers of HDPE resins are available with improved resistance to stress cracking.

Applications of HDPE range from film products to large, blow-molded industrial containers. The largest market area is in blow-molded containers for packaging milk, fruit juices, water, detergents and various household and industrial liquid products. Other major uses include high-quality, injection-molded housewares, industrial pails, food containers and tote boxes; extruded water and gas-distribution pipe, wire insulation and structural-foam housings.

Mechanically ground HDPE resins are used to rotationally mold large, complex shaped products such as fuel tanks, trash containers, dump carts, pallets, agricultural tanks, highway barriers and water and waste tanks for RV's.

A specific category of HDPE known as high-molecular-weight HDPE (HMW-HDPE) offers outstanding toughness and durability. These characteristics result from a unique combination of high average molecular weight (250,000 to 500,000) a broad molecular weight distribution and generally, a distribution that is bimodally shaped.

In blow-molding applications, HMW-HDPE allows drum manufacturers to meet DOT and OSHA specifications. The primary market, however, for HMW-HDPE is in film applications, where its toughness allows down gauging in merchandise bags and trash bags. The material is also suited for use in T-shirt-type grocery sacks where high handle strength is required. HMW-HDPE has the potential for significant paper and metal replacement on the basis of both cost and performance.