POM Celanese M90
POM Celanese M90
POM Celanese M90 is a medium‑viscosity, high‑strength, high‑rigidity polyoxymethylene copolymer. It is widely used for balanced mechanical performance, outstanding wear resistance and dimensional stability.
Main Applications
Automotive industry: fuel‑system components (pumps, valves), interior & exterior automotive fittings, seat‑belt fasteners. Industrial components: wear‑resistant, self‑lubricating engineering parts such as gears, bearings, cams, sliders, pump housings, valves and springs. Electrical‑electronic: electrical components, connectors and housings requiring good insulation and mechanical strength. Home appliances: household‑appliance parts including washing‑machine gears and coffee‑machine components. Others: precision mechanical parts, tubes, films and other thin‑wall applications.
Physical‑Mechanical‑Thermal‑Electrical Properties
| Property Category | Test Item | Test Standard | Test Data | Unit |
|---|---|---|---|---|
| Physical Properties | Density | ISO 1183 | 1.41 | g/cm³ |
| Water absorption (saturated, 23 °C) | ISO 62 | 0.75 | % | |
| Water absorption (equilibrium, 23 °C, 50 %RH) | ISO 62 | 0.20 | % | |
| MVR (190 °C / 2.16 kg) | ISO 1133 | 8.0‑9.0 | cm³/10min | |
| MFR (190 °C / 2.16 kg) | ASTM D1238 | 9.0 | g/10 min | |
| Molding shrinkage (flow direction) | ASTM D955 | 2.2 | % | |
| Molding shrinkage (transverse direction) | ASTM D955 | 1.8 | % | |
| Molding shrinkage (flow direction) | ISO 294‑4 | 2.0 | % | |
| Molding shrinkage (normal direction) | ISO 294‑4 | 1.9 | % | |
| Mechanical Properties | Tensile modulus | ISO 527‑2/1A/1 | 2760 | MPa |
| Tensile stress at yield (23 °C) | ASTM D638 | 60.7 | MPa | |
| Tensile stress at yield | ISO 527‑2/1A/50 | 66.0 | MPa | |
| Tensile strain at yield | ISO 527‑2/1A/50 | 10 | % | |
| Flexural modulus (23 °C) | ISO 178 | 2550 | MPa | |
| Charpy notched impact strength (23 °C) | ISO 179/1eA | 6.0 | kJ/m² | |
| Charpy notched impact strength (-30 °C) | ISO 179/1eA | 6.0 | kJ/m² | |
| Charpy unnotched impact strength (23 °C) | ISO 179/1eU | 190 | kJ/m² | |
| Charpy unnotched impact strength (-30 °C) | ISO 179/1eU | 180 | kJ/m² | |
| Izod notched impact strength (23 °C) | ISO 180/1A | 5.7 | kJ/m² | |
| Tensile creep modulus (1 h) | ISO 899‑1 | 2450 | MPa | |
| Tensile creep modulus (1000 h) | ISO 899‑1 | 1350 | MPa | |
| Thermal Properties | HDT @0.45 MPa (unannealed) | ISO 75‑2/B | 158 | °C |
| HDT @1.8 MPa (unannealed) | ISO 75‑2/A | 101 | °C | |
| HDT @1.8 MPa (unannealed) | ASTM D648 | 110 | °C | |
| Melting temperature | ISO 11357‑3 / ASTM D3418 | 165 | °C | |
| Coefficient of linear thermal expansion (flow) | ISO 11359‑2 | 1.2E‑4 | cm/cm/°C | |
| Coefficient of linear thermal expansion (transverse) | ISO 11359‑2 | 1.2E‑4 | cm/cm/°C | |
| Electrical Properties | Volume resistivity | ASTM D257 | 1.0E+14 | Ω·cm |
| Volume resistivity | IEC 60093 | 8.0E+14 | Ω·cm | |
| Surface resistivity | IEC 60093 | 3.0E+16 | Ω | |
| Flammability | UL94 rating (1.5 mm) | UL 94 | HB | — |
Injection‑Molding Parameters
| Parameter | Typical Value / Range | Remarks & Instructions |
|---|---|---|
| Drying Treatment | Although POM has low moisture absorption, drying is recommended. Moisture at high temperature causes degradation, bubbles and silver streaks; drying also improves dimensional stability. | |
| Drying temperature | 80‑100 °C | Dehumidifying dryer is recommended. |
| Drying time | 3.0 h | Ensure sufficiently low moisture content (normally ＜0.2 %). |
| Barrel Temperature | POM has a narrow processing window. Temperature shall never exceed 220 °C; otherwise irritating formaldehyde gas will be generated. Material residence time inside barrel shall not exceed 20 minutes. | |
| Rear zone (feed zone) | 170‑180 °C | Near feed throat. Avoid over‑temperature to prevent bridging. |
| Middle zone (compression zone) | 180‑190 °C | Main plasticizing zone; keep uniform temperature. |
| Front zone (metering zone) | 180‑190 °C | Close to nozzle. |
| Nozzle temperature | 190‑200 °C | |
| Melt temperature | 180‑200 °C | Must not exceed 220 °C. Avoid high temperature and long residence time to prevent POM degradation (decomposition temperature approx. 220‑240 °C). |
| Mold temperature | 80‑120 °C | Higher mold temperature improves crystallinity, dimensional stability and surface gloss, yet prolongs cooling cycle. |
| Injection pressure | 60.0‑120 MPa | Higher injection pressure is required due to high melt viscosity. Hold‑up pressure is generally 50‑70 % of injection pressure. |
| Hold‑up pressure | 60.0‑120 MPa | Compensates POM shrinkage, reduces sink marks and dimensional deviation. |
| Injection speed | Slow‑to‑medium | Too‑fast speed brings turbulence and burning; too‑slow speed causes short shots and prominent weld lines. Multi‑stage speed control is suggested. |
| Back pressure | 0.00‑0.500 MPa | Low back‑pressure improves melt homogeneity and degassing; excessive back‑pressure results in overheating and degradation. |
Note: All data above is for reference only.
