Polyethylene, the most type of common plastic, is thermoplastic polymer with variable crystalline structure and an extremely large range of applications depending on the type. As of 2017 over 100 million tons of PE resin is produced and accounts for 34% of the total plastics market. PE is commonly categorized into 3 major categories of LDPE, LLDPE, and HDPE.

Low-Density Polyethylene (LDPE) is a thermoplastic made from the monomer ethylene and is the first grade of polyethylene. LDPE was first manufactured in 1933 by a British company. LDPE is commonly used because it’s a flexible thermoplastic that offers stress resistance and pliability, along with strength and toughness through a wide range of temperatures.

High-Density Polyethylene (HDPE)  is a thermoplastic polymer produced from the monomer ethylene. With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, and geomembranes. USA Lining Inc. uses HDPE, LDPE, and LLDPE in manufacturing Geomembrane liner which is used for canal linings, landfills, hazardous landfills, agriculture pond lining, floating covers, mining leach pads, etc.

 

Common Uses LDPE Common Uses HDPE
Geomembrane Liner/Pond liner (USA lining Inc) Geomembrane Liner/Pond liner (USA lining Inc)
Food containers/lids Toys
Toys Water pipes
Consumer goods Food storage containers
Medical products laundry and house cleaning bottles
Food service and storage Shampoo bottles
Industrial parts Milk, water, and juice jugs
Automotive parts Detergent bottles

 

LDPE Resin identification code:

 

 

 HDPE Resin identification code:

 

LDPE and HDPE: Specifications:

  Material
  LDPE HDPE
Melt Temperature 110 °C (230 °F) 130 °C (266 °F)
Typical Injection Molding Temperature 21 - 66 °C (70 - 150 °F) 21 - 66 °C (70 - 150 °F)
Tensile Strength 7 MPa (1000 PSI) 20 MPa (2900 PSI)
Flexural Strength 6 MPa (800 PSI) 21 MPa (3000 PSI)
Specific Gravity 0.92 0.95
Shrink Rate 2.4 - 3.1 % (.024 - .031 in/in) 1.7 - 2.9% (0.017 - 0.029 in/in)

*At standard State