From flexible food packaging that can extend the shelf life of your favorite snacks to the bottles that hold your milk and everything in between, polyethylene’s properties make it the ideal material for an array of both consumer and industrial applications.
Polyethylene (PE) is available in a wide range of melt indexes and densities. That’s why it’s usable in a variety of applications from roll-out carts to lids. The versatility of the material is enabled by the way it’s produced, giving it a distinct advantage over other polymers such as polypropylene and polyvinyl chloride.
Converters can produce goods for a wide variety of applications with polyethylene resins. Popular PE variants include:
In a plant that runs different resins, the unintentional mixing of resin types is a common cause of contaminated products. For example, if PET resin is accidentally mixed in during an HDPE process, it will be present on the final product as an unmelt. This is because PET resin requires a higher melt temperature than HDPE.
Outside contamination can quickly compromise the quality and usability of a product, both in the development process and once the product is made. For example in the blow molding process, a leading cause of product quality complaints is contamination, which can be caused by a variety of factors, such as:
These issues are incredibly common and can result in defects such as die lines, streaks, bubbles, bottle in mold shutdowns, parison blow-outs, and off-coloring.
In a plant that runs different resins, the unintentional mixing of resin types is a common cause of contaminated products. For example, if PET resin is accidentally mixed in during an HDPE process, it will be present on the final product as an unmelt. This is because PET resin requires a higher melt temperature than HDPE.
Proper training on how to eliminate the unintentional transfer of contaminant substances is a positive practice to protect products in the development stage.
In its end-use form, polyethylene can be extremely resistant to outside contaminants such as chemicals or moisture. In fact, moisture resistance is one of the high-density polyethylene properties that makes it shine over similar materials. For example, it can be made into a film to protect sensitive electronics during shipping. In some instances, HDPE is used to make school lockers since they are bacteria resistant and can be easily power washed or steamed. 1 In the home care sector, HDPE bottles are typically made to contain household chemical products such as laundry or dish detergent. This is because HDPE withstands exposure to the chemicals in cleaning agents without corroding. We see HDPE bottles in industries like personal care for similar reasons.
One of the earliest developments in synthetic thermoplastics, polyethylene has several defining properties that set it apart from competing products: density and molecular weight. In particular, HDPE is available in a wide range of melt indexes and densities. This kind of versatility is a major benefit to converters because they can use different grades of PE in the variety of end-uses they produce.
In addition to molded applications like bottles and buckets, PE makes a durable film that can be used to make flexible plastic packaging for consumer products such as food and electronics.
Meet Senior Technical Service Engineer, Carl Baker. Carl Baker is a polymers visionary and industry veteran who has spent more than 30 years in the field. In roles throughout his career, his responsibilities have included working with HDPE, MDPE, and LLDPE in pipe applications and the development of PE-RT technology for the North American market.
With most consumer products, there is a risk of products falling in transit, dropping off shelves, and costing brands or stores in damaged products. That's why polyethylene’s properties (especially HDPE) make it great for a retail environment. It tougher than other plastics, while maintaining a variety of other benefits distributors and sellers look for.
In an article shared by MATEC Web of Conferences, researchers explained that the basis of their study was “HDPE is often used in a variety of impact strength demanding applications such as pipe protection for oil and gas transportation, load-bearing biomedical implants, liquid food containers, industrial vessels and automotive fuel tanks.”2
HDPE’s high impact resistance and ductility are especially great in injection molding applications. In fact, it’s why HDPE is often the material of choice for demanding industries such as medical or automotive. And due to HDPE’s high drop impact resistance, the material won’t break if dropped during use. Combining HDPE and injection molding best practices can lead to a strong part needed for exacting use.
1 https://continuingeducation.bnpmedia.com/courses/scranton-products/school-hallway-lockers-made-of-highdensity-polyethylene-hdpe/2/
2 https://www.matec-conferences.org/articles/matecconf/pdf/2017/39/matecconf_cscc2017_02050.pdf
