Traditional plastic bags are normally manufactured with polyethelene (PE). There are different types of PE. HDPE, LDPE and LLDPE are used to make plastic shopping grocery bags and trash bags, etc.
In practice the very thin bags are normally made with HDPE and thick or shiny bags are made with LDPE. LLDPE is usually mixed with other material.
Difference between HDPE, LDPE, LLDPE Resins
- LDPE (Low Density Polyethylene) has the most excessive branching. This causes the low density to have a less compact molecular structure which is what makes it less dense. It has a density of 0.910-0.925 g/cm3. The LDPE bags are more flexible but with less tensile strength.
- HDPE (High Density Polyethylene) has minimal branching of its’ polymer chains. Because it is denser it is more rigid and less permeable then the LDPE. It has a density of 0.941-0.965 g/cm3. The HDPE bags has better tensile strength but is not as flexible as LDPE bags.
- LLDPE (Linear Low Density Polyethylene) has a significant number of short branches. Because it has shorter and more branches its chains are able slide against each other upon elongation without becoming entangled like LDPE which has long branching chains that would get caught on each other. This gives LLDPE higher tensile strength and higher impact and puncture resistance than the LDPE. It has a density of 0.91-0.94 g/cm3. It is somewhere between HDPE and LDPE.
HDPE vs LDPE Bags
- LDPE Bags are shinier, thicker, more stretchable
- HDPE bags are crispy, thinner, less stretchable
Biodegradable / Compostable Bags To Replace PE Bags
Biodegradable bags are trending in the United States and Europe. It is also termed as compostable bags. They are made with corn based PLA rather than petroleum based PE. Conforming to ASTM D6400 standard.
Buy Compostable Bags and Creat Your Own Brand!
We recommend compostable for new business. It is a trending product which can be sold on Amazon or wholesale. We are a plastic bag factory in China exporting poly bags since 2005. As a manufacturer, our abundant experience make sure you get the best plastic bag for the market. The main product is plastic t-shirt bag, garbage bags, shopping bags, food bags on roll, vest bags singlet bags and so on.