UHMW Sheet, IPX 2000

IPX 2000 enhanced-wear UHMW sheet, sold by the full sheet.

IPX 2000 is an enhanced-wear UHMW compound, supplied in a distinctive burgundy so you can tell it apart on the rack. It is a single-source proprietary grade and the additive package is not disclosed on the datasheet.

The wear claim is the maker's, not ours, and we will attribute it as such: they publish a sand-slurry abrasion index of 7 against 16 for standard UHMW on their own scale, and claim up to 40 percent more wear resistance than competing UHMW grades. For reference, the index for standard UHMW across other mills runs 10 to 12 and the best branded liner grade sits at 8, so an index of 7 would make this the most wear-resistant unfilled UHMW in this catalogue. We have no independent test of it. Other published figures: tensile 5,400 to 6,000 psi, elongation 340 to 370 percent, flexural modulus 110,000 to 130,000 psi, coefficient of friction 0.09 to 0.19, notched Izod no break.

Not food contact. The manufacturer states plainly that this UHMW is not approved for food contact, so there is no FDA, 3-A, USDA or NSF route on this grade. For a food-contact wear surface, use the natural virgin grade or the metal-detectable blue.

It is for the severe-wear end of the liner and wear-strip business - chutes and hoppers handling abrasive aggregate, high-cycle conveyor wear surfaces, and anywhere standard UHMW is wearing out faster than the maintenance window allows.

UHMW is the wear material. Molecular weight in the millions - typically 3 to 6 million g/mol, ten to thirty times HDPE - gives it an abrasion life nothing else in this price range touches, and an impact behavior that simply does not break. If something slides against it, tumbles down it, or hits it, this is the material.

Friction is low but let us be accurate about it. Dynamic coefficient against dry steel is 0.10 to 0.20. PTFE is about 0.10, so PTFE equals or slightly beats UHMW - anyone telling you UHMW is slipperier than PTFE is overselling. What UHMW gives you is friction in the same range with vastly better abrasion resistance and impact strength, at a fraction of the cost. Limiting PV is about 3,000 psi-ft/min at a 4:1 safety factor.

Impact is where it is genuinely unmatched. Under the standard notched Izod test, ASTM D256 Type A, UHMW does not break - the industry had to move to double-notch methods just to get a finite number out of it, and on that method it reads around 18 ft-lb/in. Treat those as two different tests, because they are. It stays tough cold, too: brittleness temperature is below -38C and minimum service runs to -150C.

Temperature is the real ceiling and it is lower than people expect. Maximum continuous service in air is 180F. Heat deflection at 264 psi is only 116F. And the number worth pausing on: tensile strength is published at 5,800 psi at 73F and 400 psi at 150F - a 93 percent loss, and five separate grade datasheets print the same figure. We would treat anything warm and loaded as something to test rather than calculate. It melts around 270F, which is not a service temperature.

It creeps. Deformation under load runs 6 to 8 percent at 2,000 psi and 122F over six hours, and the figure the trade calls "compressive strength" - 2,400 to 3,000 psi - is itself measured at 10 percent deformation, not at failure. For a real design number use compressive stress at low strain: about 1,015 psi at 1 percent, 1,595 at 2 percent and 2,540 at 5 percent. The practical failure mode is not cracking but material flowing out from under a bolt head or a point load.

Thermal expansion is high enough to design around: 110 microinches per inch per degree F, roughly fourteen times steel. That works out to about an eighth of an inch per foot per 100F. A ten-foot liner panel moves 1.3 inches over a 100F swing, and a four-foot width moves about a third of an inch over 60F. So bolt holes want to be oversized and counterbored, fasteners must not be torqued down hard enough to stop the panel sliding, and panel joints need a gap. Ask your mill for their installation instructions - we will not invent an oversize figure for you.

Outdoor service needs a UV-stabilized grade, and color is not a substitute - black UHMW is not automatically UV-stabilized. One maker published 2,000-hour exposure data on unstabilized UHMW: its Taber abrasion index went from 2 to 182, and tensile behavior went from no break to breaking at 2,940 psi. The material that would not break now breaks. For sustained sun, specify a UV-stabilized grade and ask us.

Chemically it is good rather than universal. Acceptable in weak acids, alcohols, alkalis, chlorinated solvents, aliphatic hydrocarbons and inorganic salts. Limited in strong acids at pH 1 to 3, in hot water and steam, and in ketones and esters. Aromatic hydrocarbons are unacceptable. Water absorption is under 0.01 percent, so unlike nylon it does not swell or lose tolerance in a wet environment.

It cuts easily and holds tolerance badly, and those are two separate facts. Machinability rates 3 on a 1-to-10 scale, so a sharp tool and a high feed rate will get through it - the trick is clearing the swarf before it wraps. But it is elastic and it moves: diameters grow, so set to the low side; drilled holes close up, which makes taps tight; and residual stress redistributes after a cut and warps the part. For anything tight, rough it out, let it rest a day, then take a light finish cut.

It cannot be solvent cemented - nothing practical dissolves it at room temperature, which is the same property that makes it chemically resistant. Joining is by hot-gas welding with polyethylene rod, or mechanical fastening, which is how liners are normally installed. Adhesive bonding does work but needs the surface conditioned first: abrading at 100 to 120 grit is usually enough, with corona or flame treatment needed in a minority of cases, and a flexible epoxy is the right choice because it has to absorb that fourteen-fold expansion mismatch against steel.