POM Celanese Hostaform C9021
POM Celanese Hostaform® C9021
POM Celanese Hostaform® C9021 is a widely‑used injection‑molding polyoxymethylene copolymer with high rigidity and high hardness. It is well‑known for good thermal stability, anti‑oxidative degradation performance, favorable toughness, as well as outstanding chemical resistance and wear resistance.
Main Applications
Automotive engineering: various automotive components. Precision engineering: precision components requiring high dimensional accuracy and durability. Electrical / electronic industry: components for electrical and electronic products, such as connectors and housings. Home appliances: manufacturing of various household‑appliance parts. Engineering fittings: multiple engineering fittings requiring wear resistance and chemical resistance.
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 | 0.65 | % | |
| MVR (190 °C / 2.16 kg) | ISO 1133 | 8.0 | cm³/10min | |
| Molding shrinkage (flow direction) | ISO 294‑4 | 2.0 | % | |
| Molding shrinkage (normal direction) | ISO 294‑4 | 1.8 | % | |
| Mechanical Properties | Tensile modulus | ISO 527‑2/1 | 2850 | MPa |
| Tensile stress at yield | ISO 527‑2/50 | 64.0 | MPa | |
| Tensile strain at yield | ISO 527‑2/50 | 9.0 | % | |
| Nominal tensile strain at break | ISO 527‑2/50 | 30 | % | |
| Flexural modulus (23 °C) | ISO 178 | 2700 | MPa | |
| Charpy notched impact strength (23 °C) | ISO 179/1eA | 6.5 | kJ/m² | |
| Charpy notched impact strength (-30 °C) | ISO 179/1eA | 6.0 | kJ/m² | |
| Charpy unnotched impact strength (23 °C) | ISO 179/1eU | 180 (partial break) | kJ/m² | |
| Charpy unnotched impact strength (-30 °C) | ISO 179/1eU | 160 | kJ/m² | |
| Tensile creep modulus (1 h) | ISO 899‑1 | 2500 | MPa | |
| Tensile creep modulus (1000 h) | ISO 899‑1 | 1300 | MPa | |
| Thermal Properties | HDT @1.8 MPa (unannealed) | ISO 75‑2/A | 104 | °C |
| Melting temperature | ISO 11357‑3 | 166 | °C | |
| Coefficient of linear thermal expansion (flow) | ISO 11359‑2 | 1.1E‑4 | cm/cm/°C | |
| Coefficient of linear thermal expansion (transverse) | ISO 11359‑2 | 1.1E‑4 | cm/cm/°C | |
| Electrical Properties | Volume resistivity | IEC 60093 | 1.0E+14 | Ω·cm |
| Surface resistivity | IEC 60093 | 1.0E+14 | Ω | |
| Dielectric strength | IEC 60243‑1 | 35 | kV/mm | |
| Relative permittivity (100 Hz) | IEC 60250 | 4.00 | — | |
| Relative permittivity (1 MHz) | IEC 60250 | 4.00 | — | |
| Dissipation factor (100 Hz) | IEC 60250 | 0.002 | — | |
| Dissipation factor (1 MHz) | IEC 60250 | 0.005 | — | |
| Comparative tracking index (CTI) | IEC 60112 | 600 | V | |
| Flammability | UL94 rating (1.5 mm) | UL 94 | HB | — |
| UL94 rating (3.0 mm) | UL 94 | HB | — |
Injection‑Molding Parameters
| Parameter | Typical Value / Range | Remarks & Instructions |
|---|---|---|
| Drying Treatment | Although POM has low moisture absorption (0.65 %), drying is recommended. Moisture under high‑temperature conditions will cause degradation, bubbles and silver streaks. | |
| Drying temperature | 100‑120 °C or 80‑100 °C | Refer to the latest TDS for recommended drying temperature. Dehumidifying dryer preferred. |
| Drying time | 3‑4 h | Ensure moisture content ＜0.2 %. Material bed thickness ≤30 mm. |
| Barrel Temperature | POM has a narrow processing temperature 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 or 150‑170 °C | Near feed throat. Avoid over‑temperature to prevent bridging. |
| Middle zone (compression zone) | 180‑190 °C or 170‑190 °C | Main plasticizing zone; keep uniform temperature. |
| Front zone (metering zone) | 190‑200 °C or 180‑200 °C | Close to nozzle. Excess temperature causes POM degradation. |
| Nozzle temperature | 190‑210 °C or 170‑190 °C | Usually slightly lower than front‑zone temperature to prevent drooling. |
| Melt temperature | 190‑210 °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 | 60‑120 MPa | Higher injection pressure is required due to high melt viscosity. Hold‑up pressure is generally 50‑70 % of injection pressure. |
| Hold‑up pressure | 60‑120 MPa | Compensates POM shrinkage, reduces sink marks and dimensional deviation. |
| Injection speed | Slow‑to‑medium or medium (30‑80 mm/s) | 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 | 0.0‑0.5 MPa or 0.5‑2.0 MPa | Low back‑pressure improves melt homogeneity and degassing; excessive back‑pressure results in overheating and degradation. Adjust per TDS. |
| Screw speed | To be confirmed (30‑80 rpm recommended) | Avoid excessive rotational speed to prevent shear‑heat‑induced degradation. |
Note: All data above is for reference only.
