PBT (unfilled)
Polybutylene Terephthalate — semi-crystalline polyester with fast crystallization (short cycle times), very low moisture absorption (0.15%), excellent dimensional stability, and good electrical properties. Key advantage over PA: properties nearly independent of humidity. Trade names include Ultradur (BASF), Celanex/Crastin (Celanese/DuPont), Valox (SABIC), Arnite T (DSM). Used for electrical connectors, relay housings, automotive sensors, and any precision part in humid environments.
International equivalents
| Flag | Standard | Country | Grade | Number | Match |
|---|---|---|---|---|---|
| ISO | INT | PBT | — | REF | |
| 🇩🇪 | TRADE | Germany | Ultradur B4520 (BASF) | — | 95% |
| 🇺🇸 | TRADE | USA | Celanex 2000 / Crastin S600 (Celanese/DuPont) | — | 95% |
| 🇺🇸 | TRADE | USA | Valox 310 (SABIC) | — | 95% |
Sources: ISO 7792, BASF TDS, Celanese TDS, SABIC TDS
Chemical composition comparison (wt%)
Side-by-side: PBT (unfilled) (COMPOSITION) (ISO 7792) vs Ultradur B4520 (BASF) (TRADE)
| Element | PBT (unfilled) (COMPOSITION) | Ultradur B4520 (BASF) (TRADE) | Overlap |
|---|---|---|---|
| Base Polymer (Polybutylene Terephthalate) | 99–99.9% | — | — |
Mechanical properties
Injection Molded
| Property | Value | Unit |
|---|---|---|
| Tensile Strength | 50–65 | MPa |
| Yield Strength | 50–62 | MPa |
| Elongation | 50–100 | % |
| Elastic Modulus | 2.3–2.8 | GPa |
| Density | 1.3–1.32 | g/cm3 |
| Melting Point | 220–225 | °C |
| Glass Transition Temp (Tg) | 22–43 | °C |
| Water Absorption (24h) | 0.08–0.16 | % |
General
| Property | Value | Unit |
|---|---|---|
| Tensile Strength | 55–60 | MPa |
| Tensile Modulus | 2500–2800 | MPa |
| Elongation at Break | 50–200 | % |
| Charpy Impact (notched) | 3–5 | kJ/m² |
| Density | 1.3–1.32 | g/cm³ |
| Melting Point | 223–227 | °C |
| HDT/A (1.8 MPa) | 50–60 | °C |
| Water Absorption (24h) | 0.05–0.1 | % |
Compatibility verdict
PBT (unfilled) and Ultradur B4520 (BASF): 95% composition match
Close equivalents but NOT identical.
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