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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The quick answer is: the opposite of single use plastic.
Performance plastics are a wide range of materials that are designed for use in mechanical, engineering, aerospace, food processing, and many other applications. These performance plastic materials generally have superior physical properties, and frequently are used to replace other materials like metals, wood and glass.
Most performance plastic sheets and rods are machinable, and can be used to replace other substrates that can not stand up to the same demanding applications that these performance plastics can. Performance plastics are the natural choice when considering replacement for traditional materials, such as bronze, stainless steel, glass, wood and copper, for not just one reason but rather a combination of features and benefits.
Nearly all Performance Plastic grades can be recycled.
Because of their cost-effectiveness as well as their reliability, durability, and special characteristics like resistance to chemicals and corrosion the high performance plastic materials are steadily replacing metals in the oil and gas industry. The constant development of new and better high performance plastics is therefore closely linked to the development and economic production of the range of available performance plastic materials. High performance plastics can be divided in amorphous and semi-crystalline polymers, just like all polymers.
Performance Plastics properties
Single Use Plastic properties
Long life – up to 50 years of service
Very short, often instant throw away
Little to no physical properties
High Heat Resistance
Very low melting point
Very light weight
Can be Very UV Resistant
Very Long Life
Extremely short life
Tough and Durable
Very High Impact Strength
Flimsy, low value
Why use a Performance Plastic?
Performance plastics are designed for repeated or multi-use applications and generate a smaller carbon footprint than glass, steel, or wood. High performance plastics are plastics that can perform well under extreme environments. Because most performance plastics are considered ‘self lubricating’, these materials can be made into parts that replace metals, and don’t require the continual maintenance and lubrication that metals require.
Over the past few decades Mechanical Plastics have increasingly replaced metals due to their strength-to-weight ratios, and resistance to wear have surpassed aluminum and steel, respectively. When certain additives are blended with thermoplastic polymers, this performance plastic can meet code and compliance requirements for smoke, flammability, and even toxic gas release. Several high end performance plastics can meet the stringent FM-4910 flame and smoke rating.
Performance Plastic materials are not ‘cheap’
As opposed to ‘single use’ plastics, the performance plastic materials are not inexpensive or ‘throw away’. Rather these high performance materials are designed for specific applications, and out perform most other substrates. Other characteristics of high performance plastics can be extraordinary resistance to wear and tear, high purity or particular electrical insulation. High performance plastics are plastics that can perform well under extreme circumstances. High performance plastics are best known for their temperature, chemical and wear resistance.
Performance Plastics offers high performance plastics for high performance applications, at economical prices, made by quality American made engineering plastics manufacturers. High-performance plastics are formulated to operate under extreme chemical, high temperature and heavy load applications or any combination of these. Most performance plastics are used where the highest demands are placed on thermal or chemical resistance, product mechanics, or on the self-lubrication of products. Several of our key North American suppliers are: Ensinger Plastics, Rochling Plastics, Z/L Engineering Plastics, Simona-America, Plaskolite, and many more.
In the performance plastic market, one size does not fit all. With over 50 high performance plastics, each with its own physical properties, several materials may be proper choices for your performance plastic requirement. Please feel free to call one of our certified and trained customer service personnel for assistance in choosing the best performance plastic for your application.
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.
There are several manufactures of Gray PVC Sheet in North America. One of the best knows name for over 60 years has been Boltaron®. They have produced a high quality PVC sheet that is well know and respected. In 2004, Boltaron® acquired the assets of Empire Plastics, an Ohio based PVC Sheet producer, adding to Boltaron® overall production capacity. This acquisition was designed to also add to their already robust product line. In early 2014, Simona® America Group (also known at Simona AG) acquired all of Boltaron® Performance Products, and Simona® also acquired Laminations, Inc. of Hazleton, PA.
Simona® America is a leading producer of a wide variety of Performance Plastics including: PVC Sheet, HDPE Sheet, Polypropylene Sheet and Kynar® PVDF Sheets. The purchase of Boltaron® Plastics boosted the width and breadth of the product lines already supplied by Simona® America. With the addition of Laminations Inc., Simona® America added an industry leader in high tech plastics that meet the FM-4910 fire ratings, including: PVC, Polypropylene and Kynar® PVDF sheet materials.
For the last 3 years, Simona® America has been actively combining the product lines that Simona produced along with Boltaron® and Laminations® production, and trimming duplicate productions. A concerted effort was made to harmonize the materials, so all materials would be from the same resins and will look and perform in a similar fashion, and as a result will optimize manufacturing efficiencies.
This is just a name change and the PVC sheet will continue to be the same great product as before. There is no difference between the two materials, the name change only reflects the transition from the 2 manufacturing companies to the combined manufacturing capacity of Boltaron® and Simona® Type 1 Gray PVC Sheet and Sheeting. Type 1 PVC Sheet continues to offer one of the lowest priced materials that meets the difficult UL 94 V-0 fire rating.
There will be no change to quality or lead times, and the PVC Type 1 sheet will still be available from .060” – 4.0” thickness. One key to the Simona acquisition is that Boltaron® Performance Products has been the only North American company to produce products using extrusion, calendaring and press lamination all under one roof. Boltaron® can produce the widest thickness range of standard and specialty PVC plastic sheeting in the industry, from .003” to 4.0” thickness. They also possess the capacity to produce sheets of multi-layer composites, which can provide a broad range of physical properties.
Due to the wide range of products that Boltaron® has the capacity to produce; Simona® can now add to their offerings these additional products. The Boltaron® plant has extreme proficiency in producing PVC Sheet as well as PVC Alloys and Composites. These materials generally carry very high flame resistant ratings, and some of Boltaron® materials carry the highest ratings available from UL. Some of the most common PVC materials are the Type 1 Gray PVC Sheet, Type 2 PVC Sheet, Clear PVC Sheets, and CPVC Sheet materials. Much like a standard sheet of plywood, PVC sheet materials are normally produced in 48” X 96” sheets.
Use the best available tools to narrow down the best plastic sheet material for your application.
What are the best methods to pick the proper plastic sheet material? Use the tools that the professionals use to find the best plastic material for your application.
Where To Begin
The process of picking the proper plastic material starts with determining the ‘must have’ physical properties needed for your application. Designing a part with the minimum performance factors in mind will help to eliminate an overly expensive part.
Critical factors to consider are:
Temperature requirements (short term and long term)
Chemical or Environmental Requirements
UV resistance (Will it be in direct sunlight)
Color or Transparency
Strengths (Impact and Compression)
Compliance Issues (Certification for FDA, NSF, Dairy, etc.)
Review The Plastic Property Comparison Guide
The first tool suggested is a chart produced by the IAPD (International Association of Plastic Distribution – http://iapd.org/) linked in picture below, and listed on this chart are the most common plastic sheet and plastic rod materials that are commonlyavailable. In addition, the chart compares the physical properties of these common plastic materials. Click on picture to access chart. Included in this chart is a relative cost comparison, which will assist in limiting the materials to proper plastics for a application without over-designing and using an expensive ‘over kill’ material. Some common plastic sheet materials can be very expensive. Materials like PEEK (PolyEtherEtherKetone) can be in the $100 per pound range or more.
Start Search With Temperature Resistance
After looking over the IAPD (International Association of Plastic Distribution) Physical Properties Chart above, now it is time to evaluate specifics for your application. The critical factors listed above are ranked by most important to least important. If your part needs to handle a continuoustemperature of 300 degrees F, this is a critical physical property. Picking a material that softens at 250 degrees is a recipe for disaster. Pick a material that can handle the temperature first.
Will Part Have Chemical Exposure
Next, look at environmental requirements. Parts exposed to chemicals are important to research. Find the chemical make up and the concentration of the chemical to insure the material you pick can handle this solution. Many plasticshave excellent chemical resistance as evidenced by evaluating the container the chemicals are stored in already. Acommon plastic that is chemical resistant is Polypropylene, the same material used for automotive batteries. While Polypropylene and HDPE sheets are excellent in chemical resistance, their temperature range is quite limited. Also,these two plastics can not be easily bonded or glued, and would require heat welding for assembly.
Does Your Part Live In The Sun
Most plastics do not handle long exposure to direct sunlight without an additional UV additive. The one exception is Acrylic, which is the most UV resistant plastic sheet available. Some plastics handle UV well if they have a carbonblack additive, or a extra UV package added at time of production.
How Critical Is The Color
The most common colors in many plastic sheets are Natural (white to tan) and Black. While other colors are available with a special run, this may require a large minimum order. Some plastics, like HDPE are available in many colors andtextures for use in marine, playground and food processing applications. In many plastic applications, a machined partis being made, and the color is the least important factor. If it is an internal part of a machine, no one really cares about the color of the part. Some clients look for materials in a specific color to help ‘brand’ their parts for easy replacementand identification.
Nylon with huge amount of stress, cooled too quickly.
How Much Stress Will The Part See
Strength is a wide range of physical properties covering many stresses a part may be exposed to. From impact to compression, expansion to tensile strength, all of these can be critical in designing a plastic part. There are otherfactors in the ‘Strength’ realm, like Notched Izod and water absorption. If your part will be exposed to crushing pressure, pulling apart force or impact, these are critical things to consider prior to picking your plastic part.
PTFE is asoft and slippery plastic, but will ‘cold flow’ under high pressure, and High Pressure Laminates like G-10 FR 4 sheetcan withstand some of the highest pressures. The Notched Izod tests for materials that break easily if a scored mark has been made in the surface. Acrylics break very easily if scored, but UHMW will not break at all under the same test.
What Agency Approval May Be Required
In many applications a part may require approval or testing to meet a third party certification. One such common application is for materials in food processing applications. Common requests included UL ratings, Fire Ratings, Military specifications and many more. Food contact is a popular request, covering material that is either FDA (Foodand Drug Administration) or NSF (National Sanitation Foundation) approved. These agencies insure that materials are rigorously tested and comply with their requirements for safety. Some common materials used in food processing that meet the FDA certification are Acetal Copolymer – Acetal Homopolymer, HDPE, UHMW and Nylon, plus many others. Once these steps have been completed, several materials should present themselves as meeting your criteria andphysical property requirement. Unfortunately there is no one perfect plastic that works in all applications. However, for almost every application, there is a material that will work, and work better than most other substrates.