PTMT GF-MIN
Reinforced grade
GF-MIN = glass + mineral filled
Compromise grade: near-GF stiffness with much flatter parts for large thin covers and housings.
Values for the GF-MIN condition
Other PTMT grades and fills
PTMT is listed in 17 conditions; see the grade overview at PTMT.
Compare all 17 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Impact-modified | Use where notched impact and cold-temperature toughness dominate — snap fits, handles, exterior clips. | 40 | 42 | 200 | 68 Shore D |
PBT/ASA (or PBT/ABS) blend | Blend for weatherable, low-warp cosmetic housings needing better surface than glass-filled PBT. | 45 | 45 | 40 | 74 Shore D |
PTFE / silicone lubricated bearing grade | Internally lubricated compound for gears, cams and slide bushings running dry against metal. | 47 | 48 | 15 | 78 Shore D |
FR V-0 unfilled | For live-part enclosures and switch bodies needing V-0 at 0.75–1.5 mm without reinforcement. | — | 50 | 15 | — |
PBT/PC blend | Alloy for tough, dimensionally stable painted exterior parts (bumper fascia, trims) with better impact than neat PBT. | 55 | 55 | 120 | 76 Shore D |
Mineral-filled | Choose when flatness and isotropic shrinkage matter more than strength — flat covers, lids, painted parts. | 58 | 60 | 4 | 85 Shore D |
ESD / conductive | For electronics trays, fuel-system parts and housings needing static dissipation (10^4–10^9 Ω/sq). | — | 70 | 3 | 85 Shore D |
10 % glass-fiber reinforced | Light stiffening with modest warpage penalty; used where the unfilled grade is just too soft. | — | 80 | 5 | — |
15 % glass-fiber reinforced | Balance of stiffness and low warpage for connector bodies and covers. | — | 95 | 4 | — |
GF-MINThis page Glass + mineral filled | Compromise grade: near-GF stiffness with much flatter parts for large thin covers and housings. | 95 | 95 | 2.5 | 88 Shore D |
20 % glass-fiber reinforced | Common automotive/electrical structural grade when GF30 warps too much. | — | 110 | 3.5 | — |
flame-retardant, 30 % glass reinforced | Most-specified E&E grade: V-0 plus HDT > 200 °C for relay bases, breaker parts and connectors. | — | 125 | 2.2 | — |
Hot rolled | Carbodiimide-stabilized grades for automotive connectors and pumps exposed to hot humid air or coolant mist. | — | 130 | 2.5 | 86 Shore D |
30 % glass-fiber reinforced | The standard reinforced PBT for connectors, bobbins, brackets and under-hood parts needing HDT > 200 °C. | — | 135 | 2.8 | 90 HRM |
40 % glass-fiber reinforced | Maximum stiffness/creep resistance for metal-replacement brackets; expect anisotropic shrink and abrasive wear on tooling. | — | 150 | 2.2 | — |
50 % glass-fiber reinforced | Highest-modulus PBT compound for load-bearing housings; surface quality and toughness are the trade-off. | — | 165 | 2 | — |
CF20/CF30 | Pick for high stiffness at low weight plus static-dissipative surface; costlier and more anisotropic than glass. | — | 175 | 1.8 | — |
What is PTMT GF-MIN?
PTMT GF-MIN is PTMT in the GF-MIN grade — compromise grade: near-GF stiffness with much flatter parts for large thin covers and housings. PTMT GF-MIN has a yield strength of 95 MPa (13.8 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 93% of polymer grades. Elongation at break is 2.5% and the elastic modulus is 8 GPa (1.16 Msi). PTMT GF-MIN has a density of 1.6 g/cm³ (0.0578 lb/in³), heavier than 92% of polymer grades. Its glass-transition temperature is 50°C (122 °F).
Advantages
- High strength — 95 MPa (13.8 ksi), better than 93% of polymer grades
- Stiff — 8 GPa (1.16 Msi), better than 91% of polymer grades
- Conducts heat well — 0.31 W/m·K (0.179 BTU/hr·ft·°F), better than 87% of polymer grades
- Low moisture uptake — 0.08%, better than 80% of polymer grades
- High service temperature — 140°C (284 °F), better than 76% of polymer grades
Limitations
- Heavy — 1.6 g/cm³ (0.0578 lb/in³), worse than 92% of polymer grades
- Limited ductility — 2.5%, worse than 89% of polymer grades
- Limited formability — 12/100, worse than 83% of polymer grades
- Difficult to machine — 48/100, worse than 75% of polymer grades
PTMT GF-MIN properties
Typical room-temperature values for PTMT GF-MIN; 26 are specific to this condition. Other listed values are PTMT reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
PTMT GF-MIN has a density of 1.6 g/cm³ (0.0578 lb/in³), heavier than 92% of polymer grades. Its glass-transition temperature is 50°C (122 °F).
Mechanical16
PTMT GF-MIN has a yield strength of 95 MPa (13.8 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 93% of polymer grades. Elongation at break is 2.5% and the elastic modulus is 8 GPa (1.16 Msi).
Thermal11
PTMT GF-MIN is rated for continuous service to 140°C (284 °F). It conducts heat at 0.31 W/m·K (0.179 BTU/hr·ft·°F), better than 87% of polymer grades. Thermal expansion is 80 µm/m·K (44.4 µin/in·°F).
Electrical7
PTMT GF-MIN is an electrical insulator with a dielectric strength of 22 kV/mm (558.8 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (78/100), worse than 61% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of PTMT GF-MIN takes about 95 MJ of energy and emits 4.4 kg of CO₂ — less than 70% of polymer grades. Typical recycled content is 5%.
Manufacturability8
PTMT GF-MIN's machinability is fair (48/100, worse than 75% of polymer grades); weldability fair (40/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PTMT GF-MIN
Is PTMT easy to machine?
Machines cleanly like acetal with sharp positive-rake tools and air cooling; glass-filled grades are abrasive — use carbide/PCD and expect edge chipping on thin sections.
Can PTMT be welded?
Ultrasonic, vibration, hot-plate and laser (with laser-transparent/absorbing pairs) welding all work well; solvent bonding is impractical, use epoxy or cyanoacrylate on abraded, flame/plasma-treated surfaces.
Can PTMT be formed, bent or molded?
Dry to <0.02 % moisture (120 °C, 3–4 h) to avoid hydrolytic MW loss; mold at 250–265 °C melt, 60–100 °C tool; fast crystallization gives short cycles but 1.4–2 % shrinkage and anisotropic warpage in GF grades.
What surface finishes work on PTMT?
Takes pad printing and laser marking readily; paint and metallize only after plasma/flame or primer treatment because of the low-energy, chemically resistant surface.
PTMT chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| terephthalic acid / dimethyl terephthalaaromatic diacid segment of the repeat unit (wt % basis of neat polymer) | ≈ 62 | 62 |
| titanium/antimony catalyst residuepolycondensation catalyst, ppm level | ≈ 0.02 | 0.02 |
| glass fiberreinforcement in GF variants; chopped E-glass with silane sizing | 0 – 50 | 0 |
| flame retardant (brominated + Sb2O3 or hFR variants only | 0 – 20 | 0 |
| impact modifier / stabilizer packageelastomer, antioxidant, carbodiimide hydrolysis stabilizer, HALS | 0 – 20 | 0.5 |
| 1,4-butanediol (tetramethylene glycol) ugives the 'PTMT' (polytetramethylene terephthalate) name | balance | — |
PTMT GF-MIN — frequently asked
What is PTMT GF-MIN used for?
PTMT GF-MIN is typically used for electrical bobbins and connectors, precision gears and bushings, automotive electrical components and consumer electronics parts. In short: legacy designation for PBT; fast-cycling engineering polyester; wide filled-grade range.
What is the yield strength of PTMT GF-MIN?
PTMT GF-MIN has a typical yield strength of 95 MPa (13.8 ksi) and a tensile strength of 95 MPa (13.8 ksi) — stronger than 93% of polymer grades. Strength varies by condition: see the 17 listed tempers.
Is PTMT GF-MIN easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 75% of polymer grades). Machines cleanly like acetal with sharp positive-rake tools and air cooling; glass-filled grades are abrasive — use carbide/PCD and expect edge chipping on thin sections.
Can PTMT GF-MIN be welded?
With care — weldability is rated fair (40/100). Ultrasonic, vibration, hot-plate and laser (with laser-transparent/absorbing pairs) welding all work well; solvent bonding is impractical, use epoxy or cyanoacrylate on abraded, flame/plasma-treated surfaces.
What surface finishes work on PTMT GF-MIN?
Takes pad printing and laser marking readily; paint and metallize only after plasma/flame or primer treatment because of the low-energy, chemically resistant surface.
Can PTMT GF-MIN be formed, bent or molded?
Dry to <0.02 % moisture (120 °C, 3–4 h) to avoid hydrolytic MW loss; mold at 250–265 °C melt, 60–100 °C tool; fast crystallization gives short cycles but 1.4–2 % shrinkage and anisotropic warpage in GF grades.
What is the maximum service temperature of PTMT GF-MIN?
PTMT GF-MIN is rated for continuous use to about 140°C (284 °F), and briefly to 160°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ISO 7792-1/-2 Plastics — Thermoplastic polyester (TP) moulding and extrusion materials — ISO (2012)
- ASTM D5927 Standard Specification for Thermoplastic Polyester (TPES) Injection and Extrusion Materials — ASTM (2020)
- Ultradur (PBT) product range brochure and property tables — BASF (2023)
- Crastin PBT thermoplastic polyester resin datasheets — DuPont / Celanese (2023)
- CAMPUS plastics database — PBT unfilled and GF grades — CWFG (2024)
- Engineered Materials Handbook Vol. 2 — Engineering Plastics — ASM International (1988)
- TECADUR PBT stock shapes datasheet — Ensinger (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.