Celanese GUR UHMWPE 2122 is an ultra-high-molecular-weight polyethylene powder supplied for industrial processes that consolidate the resin without a measurable melt flow. Density by ASTM D792 is 0.930–0.935 g/cm³; average molecular weight is approximately 4.5 × 10⁶ g/mol. No melt flow rate is measurable under ASTM D1238 condition 190/21.6, and the bulk density of the as-supplied powder is 0.42–0.48 g/cm³. These properties determine the downstream production routes covered below: ram extrusion, compression moulding, pressure-free sintering, gel casting and biaxial stretching, and machining of consolidated stock.

When GUR 2122 Enters Ram Extrusion Tooling for Beverage Conveyor Guide Rails

In beverage filling and packaging lines, guide rails and wear strips are ram-extruded from GUR 2122 because the polymer cannot be screw-pumped or injection-moulded at shear rates available on standard equipment. Production-scale ram extruders use a hydraulic horizontal barrel, a heated die block, and a cooled sizing section; the powder is fed in batches, advanced by a ram at 20–40 MPa compaction pressure, and sintered against the die wall at 180–250 °C. The die wall temperature is the controlling variable because heat transfer into the core occurs by conduction through the compacted powder bed rather than by viscous shear heating. Powder lot bulk density and median particle size are monitored because a shift in packing density changes the compaction ratio and the ram pressure required to maintain a continuous profile. Surface condensation at RH > 60% in the feed hopper can generate steam pitting in the die section, so the hopper is kept under dry air. The formulation in this sector is 100 wt% GUR 2122 for natural guide rails; when black or UV-stabilised profiles are specified, 0.5–1.5 wt% carbon black masterbatch is dry-blended into the resin powder before the feed hopper. No wax, plasticizer, or heat stabiliser is used because low-molecular-weight additives migrate to the rail surface and alter the coefficient of friction. Food-contact compliance is established under 21 CFR 177.1520(c) for olefin polymers, and European conformity uses Regulation (EU) No 10/2011 with overall migration limits under Annex III/IV, provided the carbon black masterbatch has independent food-contact approval. Mechanical conformity is referenced to ASTM D4020-18 and ISO 21304-1:2020; tensile yield and elongation are measured by ASTM D638-14 on compression-moulded plaques from the same powder lot. Terminal products include guide rails of 20–80 mm width, wear strips of 5–25 mm thickness, and custom profiles cut to length for bottling and canning conveyors.

What Limits Compression Moulded Sheet Thickness in Bulk Solids Handling Liners?

Compression moulding of GUR 2122 for hopper, silo, and truck bed liners is performed in hydraulic presses with steel platens heated to 190–210 °C. The powder is loaded into the mould cavity and consolidated under 5–12 MPa; after the core reaches the set-point temperature, the platen is cooled to below 40 °C while holding pressure to suppress internal voiding and warpage. Sheet thickness is constrained by the thermal conductivity of the compacted powder, approximately 0.40–0.50 W/(m·K); sections above 80 mm require staged heating or extended soak cycles to prevent a cold unsintered core that fails in impact at the centre of the liner. In this sector, natural white liner stock is produced with 100 wt% GUR 2122; where lower thermal expansion or reduced sliding friction is needed, 5–20 wt% glass bead or 2–10 wt% molybdenum disulphide is dry-blended before mould filling, with GUR 2122 forming the remaining 80–98 wt%. Filled grades are compression-moulded rather than screw-compounded because high filler load develops black specks and particle agglomeration in a melt that cannot be homogenised. Export compliance for bulk solids handling is covered by REACH and RoHS declarations; mechanical acceptance is based on ASTM D4020-18, tensile properties under ASTM D638-14, and abrasion resistance by ASTM G65 dry sand/rubber wheel or ASTM G75 slurry abrasion ranking. Terminal products are sheets of 6–100 mm thickness that are cut, routed, or butt-welded into chute liners, hopper liners, silo transition plates, and aggregate truck bed liners. Stress relieving at 80–100 °C for 2–4 h after machining is required when the liner is intended for continuous service above 60 °C.

For sintered porous filtration media, GUR 2122 powder is screened into controlled particle-size fractions before mould filling because the final pore diameter is determined by particle size distribution, packing density, and sintering time. The powder is consolidated in steel or aluminium tooling at room temperature under 1–5 MPa and heated in an oven at 160–200 °C for 20–120 min, depending on wall thickness; no binder or porogen is required in standard grades because the pore network forms from the interstitial voids between partially fused particles. Where a bimodal pore structure is required, a second UHMWPE or HDPE powder with a different d50 is admixed at 10–30 wt%, with GUR 2122 constituting 70–100 wt% of the mould charge. Pore diameter and bubble point are characterised by ASTM F316, and multipass filter performance is validated under ISO 16889:2022; potable water contact components require NSF/ANSI 61 certification where municipal water systems are involved. The tensile strength of sintered porous parts is deliberately lower than solid moulded stock, commonly 5–12 MPa under ASTM D638-14 depending on porosity, so these components are applied as low-pressure filtration and venting elements rather than structural bearings. Terminal finished products include cylindrical filter tubes, flat filter plates, muffler vents, air diffusion stones, and sparger plates used in water treatment, pneumatic silencers, and laboratory fluid handling. Production-scale limitation: sintering above 200 °C with standard GUR 2122 causes rapid particle coalescence and collapses the pore throat, reducing air permeability by more than 30% without a corresponding strength increase.

Microporous Separator Substrate Processing Through Twin-Screw Extrusion and Biaxial Stretching

Because the wet-process separator requires a gel film that can survive sequential biaxial orientation without web breakage, GUR 2122 is selected as the base resin in lithium-ion battery separator production. The resin is not dry-blended; it is metered into a co-rotating twin-screw extruder at 180–230 °C with paraffinic white oil. The polymer phase is 15–35 wt% of the polymer–oil gel, with oil at 65–85 wt%; when inorganic filler is used to raise puncture resistance, 1–5 wt% silica or alumina is compounded relative to the polymer fraction. The extruded gel sheet is cast onto a chilled roll at 10–30 °C, then stretched sequentially or simultaneously in machine and transverse directions at draw ratios between 5×5 and 7×7. The plasticiser is extracted with methylene chloride or hexane, and the microporous film is heat-set at 110–135 °C. Cell-level compliance for this downstream sector is governed by IEC 62660-2 for cycle life, IEC 62660-3 for safety, and UL 2580 for battery packs; separator substrate tensile properties are measured under ASTM D882 and ISO 527-3, and REACH/RoHS documentation is required for export. Terminal finished products are single-layer and multilayer microporous separator films of 7–25 µm thickness, porosity of 35–50%, and Gurley numbers from 150 to 450 s/100 mL, depending on extraction and heat-setting conditions. Process limitation: the gel must be filtered through a fine-mesh breaker plate upstream of the casting die; agglomerates larger than 20 µm create pinholes that may result in a zero-voltage cell during production. Published data for GUR 2122 in multilayer separator coextrusion is limited; the values above reflect single-layer wet-process production and may shift with coextruded structures.

Paper machine suction box covers machined from GUR 2122 sheet are installed in the wet end where the polymer surface must withstand continuous wire friction, vacuum-induced abrasion, and wet-end chemical exposure. The sheet stock is produced by compression moulding at 190–210 °C under 8–10 MPa using 100 wt% GUR 2122; anti-static covers are manufactured by dry-blending 1–2 wt% conductive carbon black into the powder bed, with GUR 2122 forming 98–99 wt% of the charge, and surface resistivity is measured by ASTM D257 to confirm static dissipation. The moulded slab is cut to 20–60 mm thickness, stress-relieved at 90 °C for 2 h, and then Blanchard-ground or fly-cut to a flatness tolerance of 0.05 mm/m. Compliance for paper machine components is primarily set by equipment manufacturer specifications rather than food-contact regulations; wear ranking is performed by ASTM D3702 thrust washer wear rate and ASTM G77 block-on-ring sliding wear, while material properties are verified under ASTM D4020-18 and ISO 21304-1:2020. Terminal products include suction box covers, foil strips, forming board ledges, and dewatering strips for paper and board machines. Operational boundary: machining must be performed with sharp carbide tooling at low cutting speed because GUR 2122 does not produce a continuous chip; smeared or burnished surfaces reduce vacuum slot edge sharpness and create sheet marking.

In chemical dosing and transfer systems, GUR 2122 is machined into pump wear plates, valve seats, and plunger guides from ram-extruded rod or compression-moulded slab. The stock shape is produced from 100 wt% GUR 2122 for general chemical service; where the pumpage contains abrasive slurries, compounds are produced with 3–8 wt% graphite or 10–20 wt% glass bead, with GUR 2122 forming the remaining 80–97 wt%. The machining cell uses CNC lathes and milling centres with diamond or carbide tooling; after machining, the parts are annealed at 80–100 °C for 2–4 h to release residual stress. Chemical compatibility is evaluated according to ISO 175:2010 by immersion in the specific process fluid at the service temperature; mechanical acceptance is based on ASTM D638-14 for tensile properties and ASTM D790-17 for flexural modulus. Export compliance requires REACH and RoHS declarations, and the finished parts are inspected for dimensional stability after a 24-h soak in the target fluid. Terminal product types include centrifugal pump wear plates, reciprocating pump valve seats, and piston guides in chemical transfer, water treatment, and mineral processing. Operational boundary: continuous service temperature is limited to 80 °C under load; above this, creep under ASTM D2990 controls the design, and the component should be externally supported or replaced with a higher-temperature polymer.