POM Hengli Petrochemical HLMC90
POM Hengli Petrochemical HLMC90
POM Hengli Petrochemical HLMC90 is a high‑performance polyoxymethylene copolymer with high flowability and low‑warpage characteristics. Featuring balanced mechanical performance, excellent wear resistance and dimensional stability, it is applied in multiple fields.
Main Applications
Automotive industry: fuel‑pump gears, seat‑belt buckles (passing 100 000‑cycle durability test with wear loss＜0.1 mm), universal‑joint bearings, motor gears, crankshafts, handles, instrument panels, window lifter assemblies, electrical switches.
Industrial components: wear‑resistant, self‑lubricating engineering parts such as gears, bearings, cams, sliders, pump housings and valves. Especially suitable for precision transmission parts including printer cams and automation‑equipment guide rails, improving precision retention cycle by 30 %.
Electrical‑electronic: electrical components, connectors and housings requiring good insulation and mechanical strength.
Home appliances: washing‑machine gear sets, power‑tool housings; capable of 1000‑hour salt‑spray test, operating noise＜50 dB.
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 (24 h) | ISO 62 | 0.22 | % | |
| MFR (190 °C / 2.16 kg) | ISO 1133 | 9.0‑10.0 | g/10 min | |
| Molding shrinkage (flow direction) | ISO 294‑4 | 2.0‑2.2 | % | |
| Mechanical Properties | Tensile strength at yield | ISO 527‑2 | 62.0‑65.0 | MPa |
| Elongation at break | ISO 527‑2 | 50‑70 | % | |
| Flexural strength | ISO 178 | 85.0‑92.0 | MPa | |
| Flexural modulus | ISO 178 | 2400‑2650 | MPa | |
| Charpy notched impact strength (23 °C) | ISO 179/1eA | 7.0‑9.5 | kJ/m² | |
| Rockwell hardness (M‑scale) | ISO 2039‑2 | 78‑80 | — | |
| Thermal Properties | HDT @1.8 MPa | ISO 75‑2 | 95‑110 | °C |
| Melting point (DSC) | DSC | 166‑167 | °C | |
| Coefficient of linear thermal expansion | ISO 11359‑2 | 11‑13×10⁻⁵ | cm/cm/°C | |
| Electrical Properties | Volume resistivity | IEC 60093 | 10¹⁴‑10¹⁶ | Ω·cm |
| Dielectric strength | 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 | Although POM moisture absorption is low (0.22‑0.3 %), drying is recommended especially for damaged packaging or humid storage environment, to avoid part defects and improve dimensional stability. | |
| Drying temperature | 80‑90 °C | Dehumidifying dryer preferred. |
| Drying time | 2‑4 h | Ensure moisture content ＜0.2 %. |
| Barrel Temperature | POM has narrow processing window. Temperature shall never exceed 220 °C, otherwise irritating formaldehyde gas will generate. Material residence time inside barrel ≤20 minutes. | |
| Rear zone (feed zone) | 160‑180 °C | Near feed throat; avoid over‑temperature to prevent bridging. |
| Middle zone (compression zone) | 180‑195 °C | Main plasticizing zone. |
| Front zone (metering zone) | 190‑205 °C | Close to nozzle. |
| Nozzle temperature | 190‑200 °C | Usually slightly lower than front‑zone temperature. |
| Melt temperature | ~190‑210 °C | Must not exceed 220 °C. Avoid high temperature and long residence time to prevent POM degradation. |
| Mold temperature | 60‑80 °C (or 80‑100 °C) | Higher mold temperature (80‑100 °C): higher crystallinity, better dimensional stability & surface gloss, longer cooling cycle. |
| Injection pressure | 80‑120 MPa | High melt viscosity requires sufficient injection pressure. Hold‑up pressure: 50‑70 % of injection pressure. |
| Injection speed | Medium | Excessively fast speed causes turbulence and burning; slow speed leads to short shots and obvious weld lines. Multi‑stage speed control available. |
| Back pressure | 0.5‑2.0 MPa | Low back‑pressure improves melt homogeneity and degassing; excessive back‑pressure causes overheating‑induced degradation. |
| Screw speed | 30‑70 rpm | High rotational speed shall be avoided to prevent shear‑heat degradation. |
| Cooling time | 10‑30 s | Adjust according to part thickness and mold temperature to guarantee full cooling and deformation‑free ejection. |
Note: All data above is for reference only.
