POM DuPont Delrin 900P
POM DuPont Delrin® 900P
POM DuPont Delrin® 900P is a high‑flow, low‑viscosity homopolymer‑acetal material. It features good mechanical properties, excellent wear‑resistance and dimensional stability, and is especially suitable for molding thin‑wall articles and complex‑structure components。
Main Applications
Automotive: handle components, power‑window parts, pipeline valves, sliders, oil‑pump bearing seats, impellers, gas‑switch valves, interior & exterior door handles, crank‑type window transmission mechanisms. Electrical & electronic: washing‑machine and juicer components, timer assemblies, keyboards, audio‑video‑equipment parts, connector housings, switch parts, electric‑fan components, heating plates, instrument knobs, bearings for audio‑video tapes. Precision‑machinery & industrial components: high‑precision, wear‑resistant, low‑friction mechanical structural parts including gears, bearings, cams, screws, levers, pulleys, sprockets and engineering fittings. Consumer & others: daily‑use articles such as toys, sports‑equipment, zippers, lighters, buckles, keyboard‑keys, push‑buttons and thermostats; thin‑wall containers and packaging containers。
Physical‑Mechanical‑Thermal‑Electrical Properties
| Property Category | Item | Test Standard | Typical Data | Unit |
|---|---|---|---|---|
| Physical Properties | Density | ASTM D‑792 / ISO 1183 | 1.42 | g/cm³ |
| MFR (190 ℃ / 2.16 kg) | ASTM D‑1238 / ISO 1133 | 9.0(ASTM) / 25(ISO) | g/10min | |
| MVR (190 ℃ / 2.16 kg) | ISO 1133 | 21.0 | cm³/10min | |
| Molding shrinkage (flow) | ISO 294‑4 | 1.9 | % | |
| Molding shrinkage (transverse) | ISO 294‑4 | 1.9 | % | |
| Water absorption (24 h immersion) | ASTM D‑570 / ISO 62 | 0.25(ASTM) / 1.4(ISO,2mm) | % | |
| Water absorption (50% RH, equilibrium) | ASTM D‑570 / ISO 62 | 0.22(ASTM) / 0.30(ISO) | % | |
| Mechanical Properties | Tensile yield strength (23 ℃) | ASTM D‑638 / ISO 527‑2 | 69(ASTM) / 71.0(ISO) | MPa |
| Elongation at break (23 ℃) | ASTM D‑638 / ISO 527‑2 | 25(ASTM) / 23(ISO) | % | |
| Tensile modulus (23 ℃) | ASTM D‑638 / ISO 527‑2 | 3640(ASTM) / 3300(ISO) | MPa | |
| Flexural strength (23 ℃) | ASTM D‑790 / ISO 178 | 97(ASTM) | MPa | |
| Flexural modulus (23 ℃) | ASTM D‑790 / ISO 178 | 3220(ASTM) / 3000(ISO) | MPa | |
| Izod notched impact (23 ℃) | ASTM D‑256 / ISO 180/1A | 71(ASTM) / 7.0(ISO) | J/m ; kJ/m² | |
| Izod un‑notched impact (23 ℃) | ASTM D‑256 / ISO 179/1eU | 1620(ASTM) / 200(ISO) | J/m ; kJ/m² | |
| Compressive stress (23 ℃,10% strain) | ASTM D‑695 | 121 | MPa | |
| Rockwell hardness M‑Scale | ASTM D‑785 / ISO 2039‑2 | 94(ASTM) / 92(ISO) | — | |
| Rockwell hardness R‑Scale | ASTM D‑785 | 120 | — | |
| Dynamic friction coefficient | ASTM D‑1894 | 0.25 | — | |
| Thermal Properties | HDT (1.8 MPa) | ASTM D‑648 / ISO 75‑2/A | 136(ASTM) / 94.0(ISO) | ℃ |
| HDT (0.45 MPa / 0.5 MPa) | ASTM D‑648 / ISO 75‑2/B | 172(ASTM) / 162(ISO) | ℃ | |
| Melting point | ASTM D‑2133 / ISO 11357‑3 | 175(ASTM) / 178(ISO) | ℃ | |
| Vicat softening temperature | ISO 306/B50 | 160 | ℃ | |
| Linear thermal expansion coefficient (flow) | ASTM D‑696 / ISO 11359‑2 | 10.4‑14.9×10⁻⁵(ASTM) / 1.2E‑4(ISO) | m/m·℃ ; cm/cm/℃ | |
| Linear thermal expansion coefficient (transverse) | ISO 11359‑2 | 1.2E‑4 | cm/cm/℃ | |
| Electrical Properties | Volume resistivity | ASTM D‑257 / IEC 60093 | 1×10¹⁵(ASTM) / 1.0E+14(IEC) | Ω·cm |
| Dielectric strength (2.3 mm) | ASTM D‑149 | 19.7 | kV/mm | |
| Dielectric constant (1 MHz) | ASTM D‑150 / IEC 60250 | 3.7 | — | |
| Dissipation factor (1 MHz) | ASTM D‑150 | 0.005 | — | |
| CTI | IEC 60112 | 600 | V | |
| Flammability | UL94 rating | UL 94 | HB | — |
| Limiting oxygen index | ASTM D‑2863 | 23 | % |
Injection Molding Parameters
| Process Stage | Parameter | Recommended Range | Unit | Remarks |
|---|---|---|---|---|
| Pre‑drying | Drying temperature | 80‑90 | ℃ | Low moisture absorption (0.2‑0.5 %). Drying recommended for stable dimension and surface quality, avoid bubbles or silver streaks. |
| Drying time | 2‑4 | h | ||
| Target moisture content | ＜0.15‑0.2 | % | ||
| Barrel temperature | Rear zone | 150‑180 | ℃ | Homopolymer‑POM has narrow processing window; do not exceed 220 ℃, otherwise irritant formaldehyde gas will be generated by decomposition. |
| Middle zone | 170‑190 | ℃ | ||
| Front zone | 180‑200 | ℃ | ||
| Nozzle temperature | 170‑190 | ℃ | Slightly lower than front‑zone temperature to prevent drooling. | |
| Melt temperature | 190‑210 | ℃ | Typical range for homopolymer‑POM(POM‑H). | |
| Mold temperature | 80‑100 | ℃ | Higher mold temperature improves crystallization, dimensional stability, surface gloss and reduces sink marks. | |
| Injection parameters | Injection pressure | 70‑130 | MPa | Higher(120‑150 MPa) for thin‑wall parts; lower(80‑120 MPa) for thick‑wall parts. |
| Hold‑up pressure | 80‑100 | MPa | Sufficient hold‑pressure to reduce pressure drop and sink marks. | |
| Back pressure | 0.5‑2.0 | MPa | Keep low; excessive back‑pressure causes thermal‑shear degradation. | |
| Injection speed | Medium‑to‑high | — | Multi‑stage speed suggested; slow speed causes flow marks; excessive speed induces jetting and shear degradation. | |
| Screw speed | 30‑80 | rpm | Avoid high rotational speed to prevent excessive shear heat and material degradation. | |
| Barrel residence time | As short as possible (＜20) | min | Do not exceed 20 min at processing temperature to avoid degradation. | |
| Shutdown procedure | Short‑term shutdown | Drop barrel temperature to 150 | ℃ | Thoroughly purge barrel for long‑term shutdown. |
| Barrel purging material | PE / PP | — | Turn off heating, move screw forward. Keep barrel and screw clean. After halogen‑containing or acidic polymers, purge fully with PE before POM processing to avoid violent reaction. | |
| Post‑treatment | Annealing (if required) | — | — | Thermal treatment is required for high‑quality parts working under non‑ambient‑service condition to release internal stress. |
Note: All data above is for reference only！
