Glass-filled PET is the engineering injection grade of the same polyester family used in bottles. At 30% glass it is stiffer than PBT GF30, with higher heat deflection and a glossy surface when molded hot.
Typical PET GF30 properties
| Property | Typical value | US units | Test method |
|---|---|---|---|
| Density | 1.56–1.58 g/cm³ | 0.056–0.057 lb/in³ | ASTM D792 / ISO 1183 |
| Tensile strength | 140–160 MPa | 20,300–23,200 psi | ASTM D638 / ISO 527 |
| Flexural modulus | 9.0–10.5 GPa | 1,310,000–1,520,000 psi | ASTM D790 / ISO 178 |
| Notched Izod impact | 80–110 J/m | 1.5–2.1 ft·lb/in | ASTM D256 |
| Heat deflection, 1.8 MPa (264 psi) | 220–230°C | 428–446°F | ASTM D648 / ISO 75 |
| Water absorption, 24 h | 0.05–0.10% | ASTM D570 / ISO 62 | |
| Mold shrinkage | 0.2–0.9% | 0.002–0.009 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 | 520–570°F / 271–300°C |
| Mold temperature | 200–250°F / 95–121°C |
| Drying | 250–275°F / 120–135°C, 2–4 h virgin; 4–6 h regrind |
| Target moisture | <0.02% (200 ppm) |
| Max barrel residence | Interruption >15 min: empty the barrel |
| General | Typical |
|---|---|
| Clarity | Opaque |
| Chemical resistance | Good: oils, fuels, many solvents |
Starting points only. See the full processing temperature chart and drying guide for every resin.
What changes these numbers
- Hot mold is not optional. PET needs a mold around 95–121°C to crystallize. In a cold mold it stays partly amorphous, and parts are weaker and can warp or shrink later.
- Bottle numbers do not apply. Engineering PET is nucleated and almost always glass- or mineral-filled. Do not use bottle resin data for molded parts.
- Dry it well. Above 0.02% moisture, strength drops with no visible surface defect.
- Blends. PBT/PET blends combine PET’s stiffness and gloss with PBT’s easier molding.
Common PET GF30 grades
- GF15 to GF55
- Glass and mineral grades
- Flame-retardant grades
- PBT/PET blends
Common questions
What is the heat deflection temperature of PET GF30?
Typically about 220–230°C (428–446°F) at 1.8 MPa.
Is glass-filled PET the same as bottle PET?
Same polymer family, different grades. Injection grades are nucleated to crystallize in the mold and are almost always filled. Bottle resin is made to stay clear and amorphous.
How do you dry glass-filled PET?
About 120–135°C (250–275°F) for 2–4 hours, 4–6 hours with regrind, to below 0.02% moisture.
Need PET 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