In wet-process lithium-ion battery separator manufacturing, Asahi Kasei SUNFINE QUH972 is handled as a high-solids polymer dispersion rather than a conventional melt-flow thermoplastic. The powder is suspended in paraffin oil at an UHMWPE mass fraction of 12% to 25%, corresponding to an oil-to-polymer mass ratio of 3:1 to 7:1. Before mixing, the powder is vacuum-dried at 70–80 °C for 4–8 h when storage relative humidity has exceeded 60%, because moisture pockets nucleate pinhole defects during casting. The slurry is converted into a microporous membrane through a phase-separation and biaxial stretching sequence. A twin-screw extruder with a screw length-to-diameter ratio of 40:1 to 60:1, vacuum venting, and a melt filtration pack rated at 20–40 µm delivers the slurry to a T-die. Barrel temperatures are held between 180 °C and 230 °C; the cast gel film is cooled on a chill roll set between 15 °C and 40 °C, extracted with n-hexane or methylene chloride, and stretched biaxially at draw ratios of 5× to 7× in both machine and transverse directions. Heat setting at 110–130 °C narrows the pore-size distribution and reduces residual solvent. When methylene chloride is used as the extraction solvent, the line must meet the applicable REACH restriction and vapour-emission permit conditions; n-hexane extraction lines require explosion-proof equipment under ATEX 2014/34/EU.

Finished separators are validated under IEC 62619 for industrial battery cells, UL 1642 for lithium cell construction, and ASTM D882-18 for film tensile properties. Residual solvent limits are cell-specific and are set by the separator buyer rather than by a universal resin specification. Terminal products are lithium-ion separators for electric vehicle packs, stationary energy storage systems, and portable electronic cells.

What Limits the Dissolution Temperature Window for QUH972 in Decalin During Gel Spinning?

The upper limit is set by solvent vapour pressure and thermo-oxidative chain scission; the lower limit is constrained by incomplete crystalline melting. SUNFINE QUH972 is slurried in decalin or paraffin oil at 3–5 wt%, equivalent to a solvent-to-polymer mass ratio of 19:1 to 32:1. The mixture is heated under nitrogen blanketing at 130–160 °C until a homogeneous gel forms. At temperatures above 160 °C, decalin volatility rises and localized gel defects form at the spinneret; below 130 °C, undissolved high-molecular-weight particles survive and cause filament breakage. The gel is extruded through a spinneret with hole diameters from 0.5 mm to 2.0 mm at upstream pressure up to 12 MPa, quenched in a water bath at 5–15 °C, and extracted. Drawing is performed in two stages: first-stage draw ratios of 5:1 to 15:1 at 90–110 °C, followed by second-stage drawing at 130–150 °C to a total draw ratio of 30:1 to 60:1. The extraction solvent is removed before high-temperature drawing to avoid relaxing the gel structure and lowering final tenacity.

Ballistic applications are assessed under NIJ Standard 0101.06 or STANAG 2920; cut-resistant gloves under EN 388:2016+A1:2018; high-modulus rope under ISO 9554:2019. Terminal products include unidirectional ballistic prepregs, cut-resistant textiles, high-strength rope, and fishing line.

Ram Extrusion Pressure Drop and Die-Land Sintering Integrity

Ram extrusion does not use melt pumping. SUNFINE QUH972 powder is metered into a heated die under reciprocating piston pressure; the polymer is not plasticated to a homogeneous melt but is consolidated by particle compaction and sintering at the die wall. This conversion route requires a compression ratio of 2.5:1 to 4:1 and a die temperature profile from 190 °C to 220 °C, with back-pressure between 8 MPa and 25 MPa depending on cross-section. Heating must be graduated; an abrupt temperature rise above 220 °C creates surface degradation and internal voids, while temperatures below 190 °C leave unfused powder particles in the core. Production machines use a heated die land and a controlled cooling section. For rod diameters from 20 mm to 50 mm, ram stroke cycle times of 10 s to 15 s prevent over-compaction and thermal history drift. The powder hopper is maintained at 40–60 °C and low humidity to avoid electrostatic clumping and moisture pockets.

Stock shapes converted into food-contact wear strips are evaluated under FDA 21 CFR 177.1520 and, for the European Union, Regulation (EU) No 10/2011. The base resin is characterized by dilute-solution viscosity using ISO 1628-3 or ASTM D4020-18; melt flow rate under ISO 1133-1:2022 is not a valid quality-control parameter for this grade. Finished components include chain guides, star wheels, screw conveyor flights, wear strips, and guide rails for bottle filling lines.

When Compression Molding Replaces Injection Molding for Aqueous Slurry Pump Liners

Compression molding is the default conversion route for SUNFINE QUH972 because the ultra-high molecular weight prevents flow through runner systems and gates. The powder is charged into a mold cavity with a volume fill ratio of 2.0:1 to 2.5:1, cold-compacted at 5–10 MPa, heated to 200–215 °C, and held at 8–15 MPa for a time proportional to section thickness. Pressure is maintained during cooling until the part core falls below 60 °C; premature pressure release causes voiding and dimensional springback. Section thickness above 50 mm requires vacuum or inert-gas purging in the mold cavity because surface oxidation can produce a brittle, white degraded layer. The molding cycle for a 100 mm-thick liner can extend from 4 h to 10 h including cooling; this long thermal residence time is a known production bottleneck on compression presses.

Pump liners are dimensionally checked against customer drawings and material standards; the molded stock is specified under ISO 21304-1:2019 for PE-UHMW moulding and extrusion materials, while tensile and impact properties are measured using ISO 527-2 and ISO 179-1. End-use items are slurry pump liners, hopper liners, marine dock fender pads, and internal baffles for chemical storage tanks.

Porous sintered elements are produced from SUNFINE QUH972 by free sintering in closed stainless-steel molds at 195–210 °C for 30–60 min, with no sustained mechanical load beyond tooling contact. The powder particles fuse at contact points while retaining interstitial voids. Pore size and flow resistance are controlled by the particle size distribution and the packing density of the powder in the mold; increasing packing density from 0.45 g/cm³ to 0.60 g/cm³ produces a measurable reduction in mean flow pore diameter. Particle size distribution of the incoming powder is measured by ISO 13320:2020; finished porosity is calculated from bulk density and polymer density using ISO 1183-1:2019. Material compliance follows Regulation (EU) No 1935/2004 and FDA 21 CFR 177.1520 where the sintered part is intended for repeated food-contact use. Terminal products are pneumatic silencers, air distribution plates, wastewater aeration diffuser media, and low-pressure filter cartridges.

Solid-Phase Orientation of Compression-Molded Sheet for Cut-Resistant Tape

Oriented tape starts with a compression-molded SUNFINE QUH972 sheet, not with a gel-spun filament. The sheet is produced at 200–215 °C under 8–15 MPa, cooled under pressure, and then drawn in a forced-air oven at 120–140 °C across a temperature-controlled draw plate. Drawing is performed in discrete passes to avoid necking instability; cumulative draw ratios of 10:1 to 30:1 raise tensile modulus and reduce elongation to break. The process window is narrow because draw temperatures above 140 °C produce thermal relaxation, while temperatures below 120 °C cause fibrillation and edge cracks. Cut-resistant tapes are tested under EN 388:2016+A1:2018; tensile properties are evaluated using ISO 527-3 for film and sheet. Finished goods include high-modulus tape for braided ropes, cut-resistant arm sleeves, lightweight ballistic composite reinforcement, and industrial strapping.