POM Polyplastics DURACON M25‑44
POM Polyplastics DURACON® M25‑44 (Japan Polyplastics)
POM Polyplastics M25‑44 is a high‑viscosity general‑purpose injection‑molding grade polyoxymethylene copolymer material, renowned for outstanding mechanical strength, good heat resistance, wear resistance and dimensional stability.
Main Applications
Automotive industry: fuel‑system components (e.g. fuel pumps, fuel‑tank caps), seat‑belt parts, universal‑joint bearings, motor gears, crankshafts, handles, instrument panels, automotive window‑lift assemblies, electrical switches and other auto accessories. Home appliances: household appliances such as washing‑machines, refrigerators and electric shavers. Office equipment: mechanism gears for office equipment such as printers and copiers. Electrical‑electronic & AV equipment: AV devices including DVD players and Blu‑ray disc players; electrical components, connectors and housings requiring good insulation and mechanical strength. Other applications: residential‑sector articles such as window‑frame and shutter components, as well as game consoles.
Physical‑Mechanical‑Thermal‑Electrical‑Tribological Properties
| Property Category | Item | Test Standard | Test Data | Unit |
|---|---|---|---|---|
| Physical Properties | Density | ISO 1183 | 1.41 | g/cm³ |
| Water absorption (24 h, 23 °C) | ISO 62 | 0.50 | % | |
| MFR (190 °C / 2.16 kg) | ISO 1133 | 2.5 | g/10 min | |
| MVR (190 °C / 2.16 kg) | ISO 1133 | 2.20 | cm³/10 min | |
| Molding shrinkage (flow direction) | ISO 294‑4 | 2.2 | % | |
| Molding shrinkage (transverse direction) | ISO 294‑4 | 1.8 | % | |
| Mechanical Properties | Tensile strength (yield) | ISO 527‑2 | 59.0 | MPa |
| Elongation at break | ISO 527‑2 | 40 | % | |
| Tensile modulus | ISO 527‑2 | 2500 | MPa | |
| Flexural strength | ISO 178 | 81.0 | MPa | |
| Flexural modulus | ISO 178 | 2350 | MPa | |
| Charpy notched impact strength (23 °C) | ISO 179/1eA | 8.0 | kJ/m² | |
| Rockwell hardness (M Scale) | ISO 2039‑2 | 80 | — | |
| Dynamic friction coefficient (against POM) | JIS K7218 | 0.37 | — | |
| Dynamic friction coefficient (against steel) | JIS K7218 | 0.40 | — | |
| Thermal Properties | HDT (1.8 MPa, unannealed) | ISO 75‑2/A | 90.0 | °C |
| Coefficient of linear thermal expansion (flow, 23‑55 °C) | Internal method | 1.2E‑4 | cm/cm/°C | |
| Coefficient of linear thermal expansion (transverse, 23‑55 °C) | Internal method | 1.2E‑4 | cm/cm/°C | |
| Electrical Properties | Volume resistivity | IEC 60093 | 1.0E+14 | Ω·cm |
| Surface resistivity | IEC 60093 | 1.0E+16 | Ω | |
| Dielectric strength (3.00 mm) | IEC 60243‑1 | 19 | kV/mm | |
| Flammability | UL94 rating (1.5 mm) | UL 94 | HB | — |
Injection‑Molding Parameters
| Parameter | Typical Value / Range | Remarks & Instructions |
|---|---|---|
| Drying Treatment | Drying is not mandatory before processing, but preheating (approx. 80 °C) during processing benefits product dimensional stability. If drying is required, follow the conditions below. | |
| Drying temperature | 80.0‑90.0 °C | Dehumidifying dryer is recommended. |
| Drying time | 3.0‑4.0 h | Ensure sufficiently low moisture content (target moisture: 0.010 %). |
| Barrel Temperature | POM has a narrow processing temperature window (up to 215 °C). Temperature shall never exceed 220 °C; otherwise irritating formaldehyde gas will be generated by decomposition. Material residence time in barrel shall be limited (≤20 minutes). | |
| Rear zone (feed zone) | 180‑200 °C | Near feed throat; avoid excessive temperature. |
| Middle zone (compression zone) | 180‑195 °C | Main plasticizing zone. |
| Front zone (metering zone) | 185‑210 °C | Close to mold side. |
| Nozzle temperature | 180‑210 °C | Normally slightly lower than front‑zone temperature. |
| Melt temperature | 190‑210 °C | Do not exceed 220 °C. Avoid high temperature and long residence time to prevent POM degradation (decomposition temperature approx. 220‑240 °C). |
| Mold temperature | 60.0‑80.0 °C | Higher mold temperature (e.g. 80‑105 °C) improves crystallinity, dimensional stability and surface gloss. Take precautions against burns due to hot‑part ejection. |
| Injection pressure | 49.0‑98.0 MPa | Higher injection pressure is required due to high melt viscosity of POM. Hold‑up pressure is generally 50‑70 % of injection pressure. Relatively high hold‑up pressure (comparable to injection pressure) is needed to reduce pressure drop. |
| Injection speed | 5‑50 mm/s or high speed | Excessively fast speed causes turbulence and burning; too‑slow speed leads to short shots and prominent weld lines. |
| Hold‑up pressure | 50.0‑150 MPa | Compensates POM shrinkage, reduces sink marks and dimensional deviation. |
| Back pressure | 0.00‑3.00 MPa | Low back‑pressure improves melt homogeneity and degassing; excessive back‑pressure causes overheating and degradation. |
| Screw speed | 100‑150 rpm | Excessively high screw speed generates excessive shear heat and triggers POM degradation. Keep cushion volume low. |
Note: All data above is for reference only.
