POM DuPont Delrin 500T
POM DuPont Delrin® 500T
POM DuPont Delrin® 500T is a toughened, medium‑viscosity homopolymer‑acetal grade. It provides good dimensional stability, broad service‑temperature range, excellent wear‑resistance and balanced mechanical properties。
Main Applications
Automotive: gears, bearings, engineering fittings, pipes, handle‑parts, power‑window components and other auto‑parts. Electrical & electronic: gears, bearings and structural components for home‑appliances such as washing‑machine / juicer parts, keyboards, timer assemblies and audio‑video equipment. Precision‑machinery & industrial components: gears, bearings, cams, screws, levers and pulleys. Consumer & others: toys, sports‑equipment, zippers, lighters; extruded profiles including sheets, strips and tubes。
Physical‑Mechanical‑Thermal‑Electrical Properties
| Property Category | Item | Test Standard | ASTM Data | ISO Data | Unit |
|---|---|---|---|---|---|
| Physical Properties | Density | ASTM D‑792 / ISO 1183 | 1.39 | 1.38 | g/cm³ |
| Water absorption (24 h immersion) | ASTM D‑570 / ISO 62 | 0.31 | 0.82 | % | |
| Water absorption (50 % RH equilibrium) | ASTM D‑570 / ISO 62 | 0.27 | 0.21 | % | |
| MFR (190 ℃ / 2.16 kg) | ASTM D‑1238 / ISO 1133 | 9.0 | 12.0 | g/10 min | |
| Molding shrinkage (flow) | — / ISO 294‑4 | 1.7‑1.9 | 1.7 | % | |
| Molding shrinkage (transverse) | — / ISO 294‑4 | — | 1.6 | % | |
| Mechanical Properties | Tensile yield strength @23 ℃ | ASTM D‑638 / ISO 527‑2 | 58 | 56.0 | MPa |
| Elongation at break @23 ℃ | ASTM D‑638 / ISO 527‑2 | 91 | 35 | % | |
| Tensile modulus @23 ℃ | ASTM D‑638 / ISO 527‑2 | 2330 | 2300 | MPa | |
| Flexural strength @23 ℃ | ASTM D‑790 / ISO 178 | 70 | 60.0(3.5 % strain) | MPa | |
| Flexural modulus @23 ℃ | ASTM D‑790 / ISO 178 | 2420 | 2100 | MPa | |
| Izod notched impact @23 ℃ | ASTM D‑256 / ISO 180/1A | 143 | 14 | J/m ; kJ/m² | |
| Izod un‑notched impact @23 ℃ | ASTM D‑256 / ISO 179/1eU | ＞5300 | No break | J/m ; — | |
| Compressive strength (10 % strain) @23 ℃ | ASTM D‑695 | 82 | — | MPa | |
| Rockwell hardness M‑Scale | ASTM D‑785 / ISO 2039‑2 | 79 | 79 | — | |
| Rockwell hardness R‑Scale | ASTM D‑785 | 117 | 117 | — | |
| Thermal Properties | HDT (1.8 MPa) | ASTM D‑648 / ISO 75‑2/A | 85 | 78.0 | ℃ |
| HDT (0.45 MPa / 0.5 MPa) | ASTM D‑648 / ISO 75‑2/B | 174 | 146 | ℃ | |
| Melting point | ASTM D‑2133 / ISO 11357‑3 | 175 | 178 | ℃ | |
| CLTE | ASTM D‑696 / ISO 11359‑2 | 12.4(60‑104℃) | 1.3E‑4(flow) | 10⁻⁵ m/m·℃ | |
| Electrical Properties | Volume resistivity | ASTM D‑257 / IEC 60093 | 2.3×10¹⁵ | ＞1.0E+15 | Ω·cm |
| Dielectric strength(2.3 mm) | ASTM D‑149 | 15.1 | — | kV/mm | |
| Dielectric constant(1 MHz) | ASTM D‑150 / IEC 60250 | 3.6 | 3.60 | — | |
| Dissipation factor(1 MHz) | ASTM D‑150 | 0.005 | — | — | |
| Flammability | UL94 rating | UL 94 | HB | HB | — |
Injection Molding Parameters
| Process Stage | Parameter | Recommended Range | Unit | Remarks |
|---|---|---|---|---|
| Pre‑drying | Drying requirement | Normally not required | — | Low moisture absorption(0.27‑0.31 %). Pre‑heat ~80 ℃ improves dimensional stability. |
| Barrel temperature | Rear zone | 190‑210 practical | ℃ | ⚠️Raw‑document barrel‑setting range(193‑238/249/254℃) is erroneous for homopolymer‑POM. Practical safe melt range: 190‑210 ℃; never exceed 220 ℃, otherwise formaldehyde decomposition occurs. |
| Middle zone | 190‑210 practical | ℃ | ||
| Front zone | 190‑210 practical | ℃ | ||
| Nozzle temperature | Slightly lower than front zone | ℃ | Prevent drooling. | |
| Melt temperature | 190‑210 | ℃ | Valid for homopolymer‑POM‑H. | |
| Mold temperature | 50‑82 practical:80‑100 preferred | ℃ | Higher mold temperature improves crystallization, gloss and reduces sink‑marks. | |
| Injection parameters | Injection pressure | 80‑130 | MPa | Higher value for thin‑wall parts; lower for thick‑wall. |
| Hold‑up pressure | Close to injection pressure | MPa | Sufficient hold‑pressure to minimize sink‑marks. | |
| Back pressure | 0.5‑2.0 | MPa | Low back‑pressure to avoid shear‑thermal degradation. | |
| Injection speed | Medium | — | Strategy: medium pressure, medium speed, low melt temperature, high mold temperature. Slow causes flow‑marks; excessive speed causes jetting & degradation. | |
| Screw speed | 30‑60 | rpm | Avoid high rpm; keep small cushion to reduce shear heat. | |
| Barrel residence time | As short as possible (＜20) | min | Max residence ≤20 min to prevent degradation. | |
| Shutdown procedure | Short‑term shutdown | Drop barrel temperature to 150 | ℃ | Purge barrel fully for long‑term shutdown. |
| Purging material | PE / PP | — | Purge completely after halogen‑containing / acidic polymers to avoid violent chemical reaction. |
Note: All data above is for reference only！
