WHAT ARE HDPE, LDPE, AND LLDPE?

As you prepare to order your extruded plastic parts, you may find that the process is more complicated than you had anticipated. One significant place you might find confusing is the type of plastic you need to buy. If you order polyethylene products, you will likely see some sub-categories: HDPE, LDPE, and LLDPE. Take some confusion out of your process and learn about the differences between them. 

What Do They Mean?

HDPE stands for high-density polyethylene, and it means what it sounds like. Out of the three, HDPE has the highest density, and the polymer chains branch the least. This gives the plastic a linear structure with tightly packed molecules, which creates a dense and rigid shape. HDPE has a lot of strength to it but little flexibility because of the density.

LDPE is the opposite: low-density polyethylene. The plastic's polymer chains branch significantly more, which spreads the molecules further from each other and gives it less density and weight. The resulting material is not as strong as HDPE, but it is easy to form and mold without breaking it apart.

LLDPE indicates linear low-density polyethylene. The polymer chains of this material create a lot of branches, but they are shorter and move together well without tangling together. The combination of multiplied, less-tangled chains gives LLDPE more density than LDPE because the molecules can pack closer together. This makes LLDPE stronger and more resistant to damage.

What Are They Good For?

HDPE is one of the most common plastics in the USA. Manufacturers use the substance to create anything they plan to last a while, such as garbage containers, reusable water bottles, jugs, jars, water pipes, and baby toys. Packaging products can also use HDPE, such as milk bottles, soap dispensers, or even firework tubes.

LDPE goes into more disposable and flexible products than HDPE, like grocery bags and plastic wrap. The lining of cereal boxes usually is from LDPE as well. The material does not have to be so flimsy, though; you can also find LDPE as the material for many kinds of plastic bowls, bottles, and buckets.

LLDPE's combined strength and flexibility make it uniquely suitable for planters and products that will spend their time outside. The plastic is resistant to UV rays, which will keep the colors bright for longer, and its durability means the product will not wear away as fast from exposure to the elements. With LLDPE's resistance to force and impact damage, an object from this substance should last a long time.

What Should You Use?

Each of the plastics is useful in different ways. You may have formed an opinion already based on the description of each type, but consider the project you want to complete and the tools you'll need to make it happen. Your best chance of getting the right material is to discuss your needs with your plastic supplier and let them help you figure out what you need.

If you work on something that will need to stay in place for a long time, like a pipe system, you may need HDPE to withstand the everyday pressure of water or oil. On the other hand, if you plan to rearrange and re-sort the parts of the whole often, look for a sturdy LDPE so it can bend without breaking.

Need experts in HDPE, LDPE, LLDPE, and plastic extrusion? Seiler Plastics has you covered. With over 40 years of experience, our company can make your design into a reality, working with you to create your most challenging pieces on time and with quality. Get a quote today and see where Seiler Plastics can take you.