PBT GF30 is polybutylene terephthalate with 30% glass fiber. It is the standard resin for connectors, sensor housings and electrical parts because it absorbs very little water, holds its size and crystallizes fast for short cycles.
Typical PBT GF30 properties
| Property | Typical value | US units | Test method |
|---|---|---|---|
| Density | 1.52–1.54 g/cm³ | 0.055–0.056 lb/in³ | ASTM D792 / ISO 1183 |
| Tensile strength | 120–140 MPa | 17,400–20,300 psi | ASTM D638 / ISO 527 |
| Flexural modulus | 8.0–9.5 GPa | 1,160,000–1,380,000 psi | ASTM D790 / ISO 178 |
| Notched Izod impact | 70–100 J/m | 1.3–1.9 ft·lb/in | ASTM D256 |
| Heat deflection, 1.8 MPa (264 psi) | 200–210°C | 392–410°F | ASTM D648 / ISO 75 |
| Water absorption, 24 h | 0.06–0.08% | ASTM D570 / ISO 62 | |
| Mold shrinkage | 0.3–1.1% | 0.003–0.011 in/in | ASTM D955 / ISO 294-4 |
Typical ranges for standard grades, dry as molded, from published data sheets. Your grade’s own data sheet and the lot COA are what count. Notched Izod uses 3.2 mm (1/8 in) bars.
Processing and drying
| Processing | Typical |
|---|---|
| Melt temperature | 460–527°F / 238–275°C |
| Mold temperature | 140–212°F / 60–100°C |
| Drying | 250°F / 121°C typical / (176–284°F / 80–140°C published), 2–4 h |
| Target moisture | 0.02% |
| Max barrel residence | 5–10 min |
| General | Typical |
|---|---|
| Clarity | Opaque |
| Chemical resistance | Good: oils, fuels, many solvents; poor in hot water |
Starting points only. See the full processing temperature chart and drying guide for every resin.
What changes these numbers
- Low moisture uptake. PBT GF30 absorbs only about 0.06–0.08% water in 24 hours, so its properties do not drop the way nylon’s do.
- Still dry it. Hot, wet PBT breaks down in the barrel (hydrolysis) and parts lose strength without looking different. Dry to 0.02%.
- Hot and humid service. Standard PBT can lose properties over time in hot water or steam. Hydrolysis-resistant grades exist for that.
- Warp varies by supplier. The ratio of cross-flow to flow shrinkage ranges from about 1.3:1 to 3.7:1 between producers, so a grade switch can change how flat parts come out.
Common PBT GF30 grades
- GF10 to GF50
- Flame-retardant grades for electrical parts
- Hydrolysis-resistant grades
- Impact-modified grades
- Laser-markable grades
- PBT/PET blends
Common questions
What is the density of PBT GF30?
Typically about 1.52–1.54 g/cm³ (0.055–0.056 lb/in³).
PBT GF30 or PA66 GF30?
PA66 GF30 is stronger and handles more heat. PBT GF30 absorbs far less water (about 0.06–0.08% in 24 hours vs. 0.7–1.0%), so it holds tighter dimensions and steadier electrical properties. See glass-filled nylon vs. PBT.
How do you dry PBT GF30?
About 121°C (250°F) for 2–4 hours, to 0.02% moisture. Drop to about 93–100°C (200–212°F) if it will sit in the dryer overnight.
Need PBT GF30, or something close?
A polymer chemist reviews every request, then matches your grade or finds a qualified equivalent and prices it.
What to send for an accurate quote
- The grade name, from any supplier, or a data sheet
- Color (natural, black or a custom match)
- Fill type and percentage, if any
- Melt flow, if you know it
- Quantity for this order and what you use in a year
- Ship-to city and state or province