Material guide
PE, polyethylene
PE is the workhorse among plastics. Tough, with good sliding properties and resistant to most chemicals, cheap enough for big parts. The group runs from PE-HD in the cutting board in an industrial kitchen to PE-1000 in a slide rail that grinds heavy material around the clock.
What it is
PE, polyethylene, is one of the most used plastics there is, both in industry and in everyday life. It is a thermoplastic with good sliding properties that takes up almost no moisture and does not care about acids, bases or salts in everyday concentrations. That makes PE a first choice when you need something hard-wearing and chemically resistant without paying for an engineering specialty plastic. The difference between the grades is mostly molecular weight: the heavier the molecule, the better the abrasion resistance.
Properties
The material does not want to stick to itself or to anything else
Takes most chemicals, acids and bases in normal concentrations
Takes up almost no moisture, the dimensions hold even in a wet environment
Tough and impact resistant, even in the cold
Easy to machine, cut, weld and mill
Food approved in suitable grades
Common applications
PE is used where things wear, get wet or meet chemicals. Typical parts are cutting boards and worktops in food environments, wear plates and slide rails in conveyors, liners in pockets and chutes, plus tanks and vats in environmental and process engineering. When a customer wants something tough with good sliding properties that does not rust and takes hosing down, we usually land in PE. The material is also common in water and sewage, in manhole rings and cable protection, and outdoors in playground parts and facade panels.
Limitations
PE is not a high-temperature material. It softens long before engineering plastics like PEEK or POM do, so keep it away from hot environments. It is not stiff enough either for parts with tight tolerances under load; POM suits that better. The raw material is sensitive to UV over time if it is not stabilized, so for outdoor use in the sun you want a UV grade. Gluing is awkward on the slippery surface, and mechanical fasteners or welding work better. Think about the fire behavior too: PE burns with a clear flame and drips, so in places with fire requirements it is not the right material.
Our PE grades take 80 °C in continuous service. How far down they go varies a lot between the grades, from around -20 °C and for PE-1000 all the way down toward cryogenic temperatures, so raise it with us if the part is going to sit in the cold.
Grades and variants
PE is divided by molecular weight and use. The heavier the molecule, the better the abrasion resistance. The group runs from the standard grade PE-HD to the ultra high molecular weight grades for heavy wear parts.
Base grades
- PE-HD, high density polyethylene (sometimes written HDPE). The most common grade for most wear and chemical parts, and the one that comes in the most formats.
- PE-100, the pressure tube grade for PE tubes in pressure classes (SDR). For tubes and fittings in water and process lines.
- PE-500, the most common material in kitchens, restaurant kitchens or environments with high hygiene demands. We carry it as sheet only.
- PE-1000, the most common material in heavy applications, for example where you want to protect steel structures from wear. Ultra high molecular weight polyethylene (UHMW), the best abrasion resistance in the group.
- PE Ultra, a further development of PE-1000 with roughly twice the molecular weight. Considerably tougher and more abrasion resistant, and available in an antistatic version too.
- PE Bulk, a further development of PE Ultra with the same base material and targeted additives.
Additives and variants
- Bulk Bead, microscopic glass beads for higher abrasion resistance.
- Bulk MoS2, molybdenum disulfide as a dry lubricant for lower friction.
- Bulk UV, the antistatic version. The name is a leftover from the launch: all Bulk grades are UV resistant, it is the antistatic property that sets this one apart. The additives that give the low friction and the high abrasion resistance are the supplier's.
- Reg, recycled material where it fits, for example PE-1000 Reg.
Not all grades come in all formats, and PE grades are typically supplied in natural or black unless something else is stated.
Machining
PE saws, mills, drills and welds easily. Gluing is another matter: the surface is so slippery that adhesive gets no grip, so welding or mechanical fasteners are the way. The material is soft, so sharp tools and plenty of chip clearance give the cleanest cut.
Formats we can supply
PE comes in a wide span: sheets, round rods, tubes and hollow bars, plus roll, welding rod and Twin-Wall for welded structures. Not all grades come in all formats, see the grades above. Want a piece cut to size? Put the measurements into VisualCutter and you see the price straight away.
In depth
PE-1000 or PE-HD as the wear plate?
In hoppers, chutes, pockets and conveyors the question is often the same: should the bottom plate be PE-1000 or PE-HD? What decides it is abrasiveness, service life and price per operating hour, not the list price per square meter.
The difference is the molecular weight. PE-HD sits around 200 000 g/mol, while PE-1000 (also called PE-UHMW) sits at 5 to 9 million g/mol. The long chains make the material so tough that abrasive particles bounce instead of cutting. In sand slurry testing (ISO 15527) PE-1000 wears down 7 to 10 times more slowly than PE-HD, which in practice gives 5 to 8 times longer service life in a hopper with wet sand and gravel.
PE-1000 Reg costs roughly 1.8 to 2.2 times more per kilo than PE-HD Reg, but with 7 times the service life the cost per operating hour lands 70 to 75 percent lower. Count in changeover time and production stoppages and the saving is often more than 90 percent. That assumes wear is what drives the replacement.
PE-HD is still the right choice in several cases:
- Thin parts that have to be bent or thermoformed. PE-1000 welds poorly and does not bend below 5 mm.
- Short-term applications under about 12 months of service life, where wear never has time to become the deciding factor.
- FDA approved food parts, where PE-HD is available in virgin quality with a complete certificate.
PE-1000, on the other hand, is the obvious pick in truck beds for construction and demolition waste, sand silos, screw conveyors for cement and floor lining in crushing plants. Everywhere abrasive flows by the ton are everyday work. Work out how many hours the equipment stands still for a replacement and what a production stop costs, and the calculation gets clear.
When is recycled PE-HD (Reg) good enough?
Reg is our suffix for recycled polymer. Reg material sells today at 30 to 50 percent below virgin PE-HD and has around 80 percent lower carbon footprint. PE-1000 Reg and PE-HD Reg are post-industrial recycled material, that is offcuts from extrusion, cutting and injection molding that are regranulated and pressed into new sheets.
The raw material normally holds the same quality as virgin granulate, but the molecular weight may have dropped somewhat through the heat cycle. That gives marginally lower impact toughness and a somewhat wider spread in density from batch to batch. Yield strength and the tensile modulus stay within 5 percent of the virgin material. The color is rarely completely even: Reg sheets are supplied in gray, dark green or black, seldom white.
Reg works very well for:
- Wear plates in hoppers and chutes, where Reg and virgin come out practically even.
- Cutting boards in industrial food environments without direct contact with the end product.
- Non safety critical structural parts such as bumpers, spacer blocks, bottom plates and lids.
Reg should not be used in direct food contact where FDA or EU 10/2011 is required, since Reg has no traceability back to the original polymer. Nor in impact critical components at temperatures below 0 degrees, where the impact toughness is 10 to 15 percent lower, or where color and transparency matter to the design, since the batch can vary from gray to dark gray.
On the certificate you want to see density (0.93 to 0.95 g/cm3 for PE-HD Reg), melt index (typically 4 to 8 g/10 min) and tensile tests. A good Reg certificate reports the same parameters as a virgin certificate. If something is missing, ask us.