HDPE or High-Density Polyethylene is part of a widely-used family of thermoplastics, HDPE ‘Polyolefin’, which is produced through polymerizing ethylene and propylene for properties that are excellent in applications such as food handling, food preparation equipment, wear resistance, consumer goods, and much more.
Why this thermoplastic is so popular
HDPE is known for its excellent strength-to-density ratio, as well as its strong intermolecular forces, high impact and tensile strength. These properties combine for a hard, durable plastic that is excellent for many applications from containers for consumer goods to chemical and structural tanks components. At the same time, HDPE is lightweight and highly resistant to stains, odor, moisture, chemicals, and abrasion. Most importantly, HDPE doesn’t contain harsh or toxic chemicals that could be harmful to users, making it excellent for a wide variety of consumer and commercial products. Specifically, HDPE does notcontain: BPA, Phthalates, Allergens, Heavy Metals or Harmful fumes.
HDPE has excellent wear and chemical resistance. HDPE is a commonly used material for rub strips, chute liners and bottling plant components. An example of wear resistance is the yellow plastic playground slides which are made of HDPE. This versatile plastic material is often the choice for use for chemical and toxic containers and bottles.
The HDPE material is the common material used to make the one gallon milk jugs. These are easily recycled, and 8 – 10 milk jugs is equal to about one pound of recycled HDPE material. On average, over 115 million milk jugs are recycled each year.
Some common uses of HDPE
HDPE is FDA, USDA, and NSF compliant, making it especially popular for making components such as cutting boards, food preparation surfaces and equipment components. HDPE is often used in a wide range of food processing equipment, food containers and bottles, as well as valve and pump components. However, the Food processing industry isn’t the only industry relying on HDPE. Its excellent impact strength makes this plastic popular for everything from impact parts to dasher boards in ice rinks, to personal protection gear.
In addition, HDPE has excellent properties that make it perfect for heat-formed or vacuum-formed parts, producing food trays and containers and much more. The plastic’s durability and impact resistance makes it an excellent choice for the linings of conventional freezers, bed liners for heavy trucks, and liners in silos. The marine industry is an active user of HDPE due to its toughness and very lightweight to size ratio.
As one of the most used plastics, HDPE has a density of just .941 – .965 per ASTM D792. While many think of Aluminum as a lightweight material, it actually is 2.8 times the weight of HDPE plastic material.
HDPE also has been successfully used in a variety of cement molds and various types of transfer and storage boards. This plastic can be found in crates and bottles for holding not just food products, but also detergents and cosmetics. Industrial pallet wrapping benefits from HDPE film durability, while petrol tanks benefit from this plastic’s inherent chemical resistance.
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Industrial Plastic Supply, Inc. is an expert in performance plastics, and has one of the largest material inventories in the World. To learn more, check out full line Performance Plastic materials on our website.
Acetal Copolymer vs Dupont Delrin® Homopolymer: Properties and Benefits of Each
Industrial Plastic Supply, Inc. has been supplying a vast inventory of plastics to a wide customer base since 1975. Today, we put the spotlight on two products that are incredibly similar, but have key differences that result in each performing optimally in certain applications: the Acetal Copolymer and the Delrin® Homopolymer.
Both of these acetal materials are incredibly similar, with similar beneficial properties. They are both compliant with FDA, ITAR, and RoHS standards. Both are very stiff plastics with excellent dimensional stability in average environments. They are self-lubricating, easy to cut with standard tools, and abrasion and wear resistant. The major differences between them however are a result of their differing structures.
What Is Polyoxymethylene
Polyoxymethylene (also known as POM for short) is an important and commonly used engineering plastic material. There are two distinct types of POM; the first is Homopolymer Acetal and is commonly called Dupont Delrin®. The other is Copolymer Acetal and is referred to by the trade names Celcon®, Sustarin® C, Tecaform®, Ultraform®, Kepital® and many others. Both versions of POM are very popular thermoplastic materials. They both are commonly used for parts that need to be stiff, dimensionally stable and have low surface friction.
The homopolymer possesses much more regularity in its structure, with a repeated, crystalline pattern throughout the plastic. As a result of its strong, crystalline makeup, the Delrin® Homopolymer has superior physical properties, such as better fatigue and creep resistance, and bearing properties. Also, it has better short-term heat resistance compared to the acetal copolymer, with a much higher melting point.
However, this homopolymer does experience minor and inherent center-line porosity. This is basically a band area of tiny porous holes along the center of a rod or sheet. Depending on the severity of the porosity, these holes could weaken a finished part or cause other problems with its performance.
We’ve found that our customers tend to gravitate towards the acetal copolymer when they require a wider processing window, lower costs, and better long-term resistance to heat and alkaline environments. The acetal copolymer is not as crystalline in its structure, which causes it to not only have a generally lower melting point, but when incorporated with other materials, also increases the tolerance for high melting temperatures.
The less crystalline structure of the copolymer means that this plastic isn’t quite as strong. However, its mixed molecular structure has several benefits. The acetal copolymer has improved resistance to oxidation, improved chemical resistance, and much better long-term resistance to heat. That difference in chemical resistance is much more pronounced with exposure to hot water, especially chlorinated water. The acetal copolymer survives much longer than the homopolymer in these conditions.
Both the Acetal Copolymer and the Delrin® Homopolymer have their benefits. Depending on your application and requirements, you can choose the best acetal based plastic for your needs. In need of a supplier of plastics and plastic materials? Check out the rest of Industrial Plastic Supply today!