HDPE vs UHMW: When to Use High-Density Polyethylene
HDPE and UHMW are popular and well known types of plastics across many different industries for their reliability, so much so that many people have started to use them interchangeably. However, their uses don’t coin cide nearly as often as many think–HDPE has different qualities that lend well to different applications. While both materials are very light, with a density of .94 – which means they both float in water.
When best to use HDPE
High-Density Polyethylene or HDPE is known for its versatility and low moisture absorption, which result from its high-density chemical makeup. Its chemical composition also makes it highly chemical resistant, so it’s excellent for applications that involve moisture or mild chemicals.
HDPE is also very easy to machine and shape. As a result, it has been used successfully to make plastic lumber, milk jugs, containers, cutting boards, and many other products.
In addition to being easy to machine, HDPE sheet and rod are also relatively lightweight, and can be NSF and FDA compliant. This very durable material can not be glued or bonded, and thus must be heat welded together or attached with mechanical fasteners. HDPE is excellent for applications where reduced weight and low costs are paramount. This, combined with its easy machinability, allows HDPE to be cut, drilled, routed and shaped for many different end uses. Food cutting boards, piping, storage vessels, marine components, and many more benefit from HDPE. It’s also been successful in outdoor furniture, signage, playground equipment, structural tanks, food processing equipment, vacuum-formed parts, transfer boards, tank liners–and this is just a small number of its applications.
When not to use HDPE
While HDPE and UHMW have similar properties, they are often better suited to different tasks. Both plastics do have high impact resistance, but UHMW (Ultra-High Molecular Weight Polyethylene) performs better in applications where friction and constant impact are present. The UHMW molecular chain is much longer, thus giving UHMW the extreme wear resistance. This results in UHMW being used more often in functional components, like conveyor systems, concrete chute liners, mated parts, bumpers, and bearing applications. HDPE does not perform as well as UHMW under constant friction, making HDPE better for food processing surfaces, chemical resistant parts, decorative products, or components that will not experience constant friction. If a reduced friction application is needed, the use of UHMW with a coefficient of friction of just 0.08 (compared to HDPE with a coefficient of friction of 0.20) is much more suitable.
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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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Why food safe HDPE plastic replaced glass as the go-to milk container.
Many of you, should you be older than 60, may remember the “Milk Man”. This delivery service from decades ago, was a most common way of transporting milk to the consumer. Back then, suppliers used glass bottles, delivered by this milk man, right to your front door.
HDPE is Food Safe
When looking at alternatives, the milk processing industry found a use and benefit from replacing the glass with a plastic called High Density Polyethylene (HDPE). But what is HDPE, and what are the benefits of using it?
Glass is heavy, HDPE plastic is light
One of the characteristics of this thermoplastic is the weight of the material. The reason this is so beneficial brings us back to the milk jug. Old style glass milk containers could hold 32 oz., with the empty glass weighing 1.25 lbs. An empty gallon water or milk jug (128 oz.) weighs in at only 0.25 lbs, and holds 4 times more volume. When full, the milk jug can hold more volume than the glass bottle without compromising the strength, especially when being transported. This lowers the overall transport time and significantly reduces the cost of shipping.
This drop in weight and large increase in capacity is why the industry made the switch. The attribute of high durability in plastic materials like HDPE is known as the “strength to weight ratio”. As already mentioned, this was a huge benefit from switching to HDPE containers – the impact it has on transport costs. The high impact resistance of the material allows for easy transport. The HDPE jugs can withstand the jarring and bumping that is a natural part of mass transit, with almost zero wear or breakage to the product. Compared to the glass bottle, too hard of a turn or a pothole in the road could lead to the disheartening sound of shattering glass… not an ideal result for the distributing company. The HDPE impact resistance still holds true through out the supply chain, and even when the containers enter a store or home. If a HDPE milk jug should fall, the plastic container may spill, but it won’t cause the harm or damage that glass would. Broken glass poses a hazard and a risk, whereas plastic in this case can be easily cleaned, recycled, and used again.
When discussing this topic, the argument of recycling and sustainability sets its sights on plastics. In reality, the carbon footprint of plastics is much smaller than that of glass. The amount of heat necessary to heat up plastic for recycling is dramatically lower than that of glass, making it more sustainable in the long run. Yes, both are 100% recyclable, but the amount of fuel necessary plays a big factor. The temperature needed for melting and processing HDPE is between 248 and 356°F depending on grade. Whereas glass materials requires a minimum temperature of 2,600°F, according to SeattlePI. As you can see, these temperatures are very different, and shows why the life cycle of plastic is more eco-friendly and a better option to preserve our environment.
Immensely versatile HDPE applications
HDPE has many more uses, like in structural tanks, FDA approved cutting boards and industrial piping systems. This material outweighs most alternatives in benefits due to it’s cost and performance, and is produced in sheet and rod by many major manufacturers in the USA. HDPE plastics are FDA and NSF approved for food applications, making HDPE a food safe product for most food processing and packing applications. For more details on HDPE and it’s benefits see Industrial Plastic Supply or call 866-832-9315
What other applications could benefit from newer and improved materials to make our world safer, cleaner and more efficient?
The history of metals is thought to have begun with the use of copper about 11,000 years ago. Gold, silver, iron, lead, and even some brass began to be used before the first known appearance of bronze in the 5th millennium BCE
Artifacts made of smelted iron have been found dating from about 3000 BC in Egypt and Mesopotamia. In those times, iron was a ceremonial metal; it was far too expensive to be used in everyday life. Metals are commonly very stiff, tough and strong. However, they are also generally quite heavy. Also, the cost to heat metal to production temperatures is extremely high, over 5 times that of Performance Plastic materials. When metals corrode they get smaller, and many can decompose to yield rust.
In comparison, plastics only were first made in the early 1900’s. The world’s first known fully synthetic plastic was bakelite (now days considered Phenolic), and was invented in New York in 1907 by Leo Baekeland who coined the term ‘plastics’. Since this date, thousands of chemists and material scientists have synthesized dozens of plastic base materials. Plastic materials are currently available in over 80 types, and each of these are molded or processed at slightly different temperatures. The wide range of performance plastic materials will allow you to choose the perfect material for your next application.
Some of The Advantages of New Performance Plastic Materials
New Higher Temperature Performance Plastic Materials
New Performance Plastic materials like Victrex 450g PEEK and Sabic Ultem 1000 have much higher use temperatures over previous performance plastic materials. The Ultem 1000 unfilled has a continual use temperature above 400 degrees F, while the newer Victrex 450g PEEK materials work well at 480 degrees F on a continuous basis. In addition to the higher temperatures, they are still food grade materials.
Most plastic materials can typically be molded in a temperature range of 400 to 600 degree F. While steel starts to melt at 2,500 degrees F. This is five times the temperature, meaning it takes 5 times the energy to convert steel instead of plastic. Lower temperatures equates to lower costs of production.
New Lower Weight Materials
The average plastic weighs just 20% of the average metal product. Many plastics have exceptional weight to strength ratios, meaning that for the weight of the product they are very strong. This low weight means much less raw materials and less impact on the environment if using plastics over metals. This results in lower cost to manufacture parts from plastics over metal.
For instance, new UV grades of HDPE or High Density Polyethylene are very light, with a density of just .96, so light it floats in water. And yet, this new UV grade of HDPE is a workhorse in the plastic market, and is used to replace wood and metals in outdoor furniture.
New Detectable Materials For Food Contact Approved
Most Performance Plastic materials were engineered to be food contact compliant, and in most cases FDA approved for food contact. With the increase in food recalls, finding the proper materials to ensure that our foods are safe is imperative. Materials like Acetal Copolymer, Acetal Homopolymer, Nylon, Ultem 1000 and Victrex 450g PEEK are all FDA approved for direct food contact.
Which Performance Plastic Will Work The Best
Here are some new performance plastic material grades that include additives to make these materials detectable during food processing. These newly released detectable products include Tecaform AH UD (copolymer acetal base), Tecapeek UD Blue (PEEK based) and Hydex 4101 UD Blue PBT – Polyester base). Each of these new performance plastic materials comes in Blue color to be detected by color sensors during food processing. The “UD” portion allows these materials to be detected by X-Ray and Metal Detection scanners in food processing production lines. Using these new detectable performance plastic materials in food processing plants can help to eliminate food contamination issues and massive food recalls.
Recent Rising Costs Of Transportation
Changes in transportation rules and regulations since 2018 have made shipping raw materials significantly more expensive. Weight, size restrictions and surcharges for longer packages have more than doubled in the last year.
This has made one of the most expensive components of materials reaching the marketplace is transportation costs, and over the last several years the costs of moving materials across the country has skyrocketed. Metals are heavy, and this weight makes many items very expensive to transport.
Each step in the production of a finished good generally involves shipping to the next step. Raw material converted into base material, then base material converted into usable shape. Later this shape is turned into a component or part. Each time there is a conversion, there normally is shipping to the next processor. Metal weight can limit the amount of metal that can be moved at one time, where plastics can ship up to five times more product per truckload.
With performance plastics, often the conversion in small factories that can be located near final assembly of components limits the amount of shipping of plastic parts. Also, due to the light weight of plastics, trucks can hold up to five times the amount of plastic over metals for shipping. Many plastic parts are made very close to where they will be consumed, cutting logistics fees. This five times the weight also translates to five times higher cost to ship metals. This reduction of transportation costs moves more profit to the bottom line.
New Performance Plastic Materials Eliminate Need For Lubrication
Often, on large metal parts or assemblies, grease ports are added to make lubricating the metal parts easy. Metal on metal parts will wear out very quickly, and therefore require regular service and lubrication.
Newly released performance plastic materials have made lubrication obsolete. One such material is a new compounded Nylon material, called Nylatech PVM has FDA approved oil additives. This new Cast Nylon material runs well for extended periods without external lubrication. This material runs quieter and smoother than previously used metal parts due to a much lower coefficient of friction, and requires no regular maintenance.
Another new grade of Performance Plastic material that is rated as ‘self-lubricating’, and have excellent wear resistance is Lub-X UHMW, which now makes curves in bottling plants move smoother, quieter and require no lubrication. These long wearing and high strength materials outperform most other substrate for low cost, high performance, low weight and self lubrication.
Each of these plastic advantages yield cost savings and long product life. Along with these new areas of advantage, Performance Plastics are 100% recyclable, and can be reprocessed into high strength parts again and again. The plastic recycling industry is still in its infancy, and as it becomes more adept at recycling and reusing valuable plastic materials, our planet and our pocket books will benefit.
Yes, UV Resistant Recycled Plastic Lumber lasts and lasts
What happens to your ‘blue recycled trash’ materials? A common question regarding recycling is, ‘Does It Work’?
The answer is ‘YES’ it certainly works.
One of the most recycled plastic materials is HDPE. This is the material that laundry detergent bottles, milk jugs, opaque vitamin bottles and many more common household containers are made from. The HDPE is a FDA and NSF approved resin, and is the go to material for cutting boards, margarine containers, food storage containers, and many of your milky colored drinking cups.
So, what happens to these items after you put them into your recycle bin?
Your local recycling center sorts through your clean recyclables and segregates the materials by the type of plastic. HDPE has the recycle code of #2, and this can be found on the bottom of many of your plastic items. The other plastic items are sorted out based on the recycle number and type of material. This allows for better and more efficient reprocessing of these resins into new and re-purposed items.
The reprocessing of plastic scrap or discarded post consumer products generated a large quantity of plastic material. The HDPE recycling market is a fast growing area of the recycled plastic sector. The other common plastic that is recycled is PET, which has the code of #1, and this is the very clear water bottles and soda bottle material.
Once the discarded containers and other HDPE scraps are collected, they are sent to a recycle plant. This is where the containers are cleaned, sent to the grinder, and converted into small pieces that can be used in the manufacture of new products. This reprocessing of post consumer goods into a usable plastic lumber is the first step in the recycling process. Much later, after the very long life of the HDPE recycled lumber is over, it can be again reprocessed into another recycled HDPE product, maybe even another piece of HDPE plastic lumber. The cycle of using an already produced plastic product, and then reusing, recycling or re-purposing this material is as environmentally responsible as any consumer can be. This ‘closed loop’ recycling eliminates the use of other natural resources, and cuts the impact on our planet.
In a recent press release, HDPE recycled content from milk jugs, laundry detergent bottles, shampoo bottles and other post consumer content are gathered. Then it is ground to usable sizes, and then reprocessed into Recycled HDPE Plastic Lumber. The only additive are the colorant and a UV stabilizer or UV resistant additive. The material is sent threw an extruded or molding process, and the result is a plastic boards that look like real wood, but will out last any wood product by 5 – 10 times, and not require the maintenance that we know is required with wood lumber. The premium recycled HDPE plastic lumber, made by Bedford Technologies, has a 50 year warranty.
That’s a long time, our UV Resistant Recycled Plastic Lumber will last.
Plastic lumber does not rot, splinter, require paint or sealants annually, nor any other regular maintenance. Perhaps a semi-regular washing down is all that would be needed to have this material continue to look like new.
What are popular items that are made from this recycled HDPE plastic lumber? The limit to uses is only limited by your imagination. Some of the most common HDPE plastic lumber products are: outdoor decks, outdoor furniture, docks for lakes and marinas, trellises, walkways, playground components, parking bumpers, sign posts and many more. All of these items outperform the lumber products previous used for these applications.
Call us for more information on the available sizes and colors of recycles HDPE plastic lumber, 866-832-9315.