The Differences Between LLDPE, LDPE & HDPE

Polyethylene is the cornerstone of the polyolefin resins family. It holds unparalleled significance in the domain of polymers. Indeed, it stands as the most utilized polymer globally. You will find its ubiquitous presence in modern manufacturing. You can find Polyethylene’s application in plastic bags to container. It is also used in films, tubes, toys, and automobiles.

If you further explore the world of polyethylene, you are likely to unveil its myriad applications across industry. PE encompasses a spectrum of types such as HDPE, LDPE, and LLDPE granules. Understanding the distinctions between these variations and their respective uses is pivotal. It is particularly important to comprehend the diverse landscape of PE-based products. We can classify the various types of polyethylene into three main compounds. They are HDPE, LDPE and LLDPE granules. Let’s dive into each compound in detail:

What is HDPE?

High-Density Polyethylene (HDPE) finds widespread usage in numerous applications, including plastic pipes. HDPE resins offers several advantages such as sustainability, resistance, flexibility, and food safety. However, they also present certain drawbacks. These drawbacks include bonding difficulty and sensitivity to stress cracking. It also exerts nonflammability, and poor weather resistance features.

What is LDPE?

Low-Density Polyethylene (LDPE) is extensively utilized in various applications such as tubing. LDPE features numerous branches compared to HDPE. LDPE material offers advantages like excellent electrical insulation. These advantages also include easy molding and processing, and waterproof properties. However, it is susceptible to crack stress and lacks UV resistance. It also exhibits poor performance under extreme temperatures,

What is LLDPE?

Linear Low-Density Polyethylene (LLDPE) is commonly employed in applications like stretch wraps. LLDPE granules offers advantages such as chemical and mechanical resistance and a natural milky color. It also offers flexibility with high impact strength. Nonetheless, it faces challenges in processing compared to LDPE. It also exhibits lower heat-sealed characteristics.

Applications 

The above section shed light on the diverse properties and applications of each type of polyethylene. Thus, offering valuable considerations for various industrial and commercial uses.  Each type of polyethylene presents a distinct array of benefits. Thus, making PE suitable for diverse industrial applications.

• LDPE granules finds extensive use in lightweight packaging materials. Its application includes waterproof carton lining and plastic wraps. Additionally, it serves applications such as computer hardware covers, packaging, wash bottles, and more.
• HDPE is employed in robust packaging materials. Its application includes plastic milk bottles, drums, bulk containers, and industrial bottle caps. Moreover, it finds utility in pipes, tubing, and the fabrication of plastic chairs and tables.
• LLDPE granules are utilized in extrusion coating applications. It helps in safeguarding the contents of liquid containers. Simultaneously, it also provides flexibility and durability.

Density

• LDPE exhibits a low density ranging from 0.91 to 0.925 g/cm³.
• HDPE displays a higher density within the range of 0.941 to 0.965 g/cm³.
• LLDPE falls within the density range of 0.91 to 0.94 g/cm³.

Chemical structure

• LDPE granules are manufactured via free radical polymerization. Thus, yielding chains with varied lengths of branching. This characteristic grants LDPE high ductility. LDPE possesses lower durability and tensile strength compared to other types.
• HDPE comprises polymer chains with fewer branches. Thus, leading to tightly packed and bonded molecules. Making it more sturdy and rigid.
• LLDPE granules, distinguished by its increased flexibility compared to LDPE and HDPE. LLDPE owes this attribute to its multiple short branches. These branches facilitate smooth sliding against each other without tangling. Thereby enhancing LLDPE’s overall flexibility.

Chemical Resistance

HDPE, LLDPE, and LDPE – all these plastic materials exhibit excellent resistance to most alcohols, solvents, alkalis, and acids. But they have low resistance to most selected hydrocarbons.

Heat Resistance

• LLDPE exhibits the lowest heat resistance among the three. Its density significantly decreases when exposed to temperatures exceeding 20 degrees Celsius.
• HDPE can endure temperatures exceeding 100 degrees Celsius.
• LLDPE demonstrates superior resistance to low-temperature heat.

Melting Points 

Polyethylene transitions into a liquid state at its melting point. Thus, facilitating effortless injection molding and subsequent recycling.

• The melting point of LDPE and HDPE typically ranges between 110 and 135 degrees Celsius.
• LLDPE granules has a melting point of 122 degrees Celsius.

Flexibility and Thickness

• HDPE exhibits flexibility but is relatively more rigid compared to LDPE.
• LDPE is highly flexible.
• Similarly, LLDPE granules also demonstrate high flexibility.

Color

• HDPE naturally appears as milky white. It may be semi-translucent based on its density.
• LDPE exhibits a natural milky color and is translucent.
• LLDPE granules also present a natural milky color and is translucent.

Recycling Polyethylene (PE)

1. HDPE (High Density Polyethylene)

HDPE is highly recyclable, allowing for multiple recycling cycles. It stands out as one of the easiest plastics to recycle and can be reused repeatedly. Most recycling programs worldwide accept HDPE materials.

2. LDPE (Low Density Polyethylene)

Recycling LDPE presents certain challenges. This includes -plastic bags becoming entangled in recycling machinery. The recycling process for LDPE typically takes longer compared to other materials. Before recycling, LDPE granules require extensive preparatory steps such as cleaning and sorting.

3. LLDPE (Linear Low-Density Polyethylene)

LLDPE is among the most commonly recycled materials. Its properties remain largely unaffected by the recycling process. Thus, allowing for multiple recycling cycles.

Conclusion

HDPE is an ideal choice if your project demands durability. It is also suitable for projects looking for chemical resistance. However, if you seek ease of installation and do not require the same level of strength as HDPE, LLDPE may prove to be the better option. Here at AVH, we strive to deliver high quality polymer. If you don’t know what to choose, contact experts at AVH. We can help you choose the right products for your project.