Polyethylene (PE)
is a polymer produced through the polymerization of ethylene. PE is
widely used in various forms of flexible protective packaging, including
shrink wrap and stretch wrap, with significant performance variations
among different types.

PE can be produced in multiple forms, the three most common being Low-Density Polyethylene (LDPE), Linear Low-Density Polyethylene (LLDPE), and High-Density Polyethylene (HDPE). Each type is suited to different industrial applications, with LDPE being the most commonly used form for shrink wrapping.

A
key advantage of LDPE for shrink wrapping is its enhanced strength and
durability, making it ideal for larger, heavier items such as beverage
multipacks. These films can also be printed with high-quality graphics
while maintaining both visual appeal and structural integrity.

PE films are typically available in thicknesses of 40, 60, 80, 100, and 120 microns. However, PE shrink film has certain limitations: its shrinkage rate is relatively low, generally not exceeding 20%, and it offers lower transparency compared to other shrink film materials.

Polyethylene is categorized based on polymerization methods, molecular weight, and chain structure into:

• HDPE

• LDPE

• LLDPE

LDPE,
commonly known as high-pressure polyethylene, is soft and low in
density. It is primarily used in plastic bags and agricultural films.

HDPE,
often referred to as low-pressure polyethylene, offers higher heat
resistance, oil resistance, steam barrier properties, and environmental
stress crack resistance compared to LDPE and LLDPE. It also excels in
electrical insulation, impact resistance, and cold temperature
performance, making it suitable for blow molding and injection molding
applications.

LLDPE
is a copolymer of ethylene and a small amount of higher olefins
polymerized with a catalyst. While similar in appearance to LDPE, LLDPE
has slightly lower transparency but better surface gloss. It offers
excellent low-temperature toughness, high modulus, resistance to bending
and stress cracking, and improved impact strength at low temperatures.