PBT IM (Impact modified)
Grade
also Crastin, Pocan
Use where notch sensitivity or cold (-30 °C) impact is the failure mode — snap fits, exterior clips, mirror housings.
Values for the IM condition
Other PBT grades and fills
PBT is listed in 10 conditions; see the grade overview at PBT.
Compare all 10 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
IMThis page Impact modified | Use where notch sensitivity or cold (-30 °C) impact is the failure mode — snap fits, exterior clips, mirror housings. | 42 | 200 | ||
PTFE/silicone lubricated bearing grade | Choose for sliding gears, cams and bushings needing low friction and wear without external lubrication. | 48 | 48 | 20 | 78 Shore D |
Flame retardant, UL 94 V-0 | Choose for electrical housings, relay bases and connectors that must carry a UL 94 V-0 listing at 0.8–1.5 mm wall. | 52 | 8 | ||
Heat stabilized | Pick for automotive electrical parts that must survive thousands of hours at 130–150 °C without embrittlement. | 55 | 55 | 80 | 82 Shore D |
ESD / conductive | Use for static-dissipative fixtures, fuel-system and electronics handling parts requiring 10^4–10^9 Ω surface resistivity. | 60 | 60 | 5 | 84 Shore D |
Mineral / glass-mineral filled, low warpage | Choose for flat, dimensionally accurate covers and lids where isotropic shrinkage and good surface beat maximum strength. | 85 | 3 | ||
15% short glass fiber reinforced | Mid-way grade when you need roughly double the stiffness and 200 °C HDT but want lower warpage and better surface than GF30. | 95 | 3.5 | 85 HRM | |
30% glass fiber, UL 94 V-0 | Standard for connectors, coil bobbins and switchgear needing both V-0 and >200 °C HDT with high stiffness. | 125 | 2.2 | ||
30% short glass fiber reinforced | The workhorse structural PBT: choose for stiff, creep-resistant, heat-resistant parts (connectors, housings, brackets) where warpage can be managed by gating. | 135 | 2.8 | 90 HRM | |
40% short glass fiber reinforced | Maximum stiffness/strength PBT for metal-replacement structural parts; accept higher warpage, brittleness and tool wear. | 155 | 2.3 |
What is PBT IM?
PBT IM is PBT in the IM grade — use where notch sensitivity or cold (-30 °C) impact is the failure mode — snap fits, exterior clips, mirror housings. PBT IM has a yield strength of 55 MPa (7.98 ksi) and a tensile strength of 42 MPa (6.09 ksi) — stronger than 62% of polymer grades. Elongation at break is 200% and the elastic modulus is 1.9 GPa (0.276 Msi). PBT IM has a density of 1.26 g/cm³ (0.0455 lb/in³), heavier than 66% of polymer grades. Its glass-transition temperature is 55°C (131 °F).
Advantages
- Low moisture uptake — 0.09%, better than 79% of polymer grades
- Ductile — tolerates forming and impact — 200%, better than 76% of polymer grades
PBT IM properties
Typical room-temperature values for PBT IM; 11 are specific to this condition. Other listed values are PBT reference data and may not represent this condition. Bars are the position among polymer grades.
Physical5
PBT IM has a density of 1.26 g/cm³ (0.0455 lb/in³), heavier than 66% of polymer grades. Its glass-transition temperature is 55°C (131 °F).
Mechanical17
PBT IM has a yield strength of 55 MPa (7.98 ksi) and a tensile strength of 42 MPa (6.09 ksi) — stronger than 62% of polymer grades. Elongation at break is 200% and the elastic modulus is 1.9 GPa (0.276 Msi).
Thermal11
PBT IM is rated for continuous service to 110°C (230 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), better than 72% of polymer grades. Thermal expansion is 80 µm/m·K (44.4 µin/in·°F).
Electrical7
PBT IM is an electrical insulator with a dielectric strength of 23 kV/mm (584.2 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (82/100), better than 56% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of PBT IM takes about 105 MJ of energy and emits 5 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 5%.
Manufacturability8
PBT IM's machinability is good (60/100, better than 51% of polymer grades); weldability very good (70/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PBT IM
Is PBT easy to machine?
Machines cleanly with sharp, positive-rake carbide tools and air cooling; glass-filled grades are abrasive and need diamond or coated tooling, and sharp internal corners must be avoided due to notch sensitivity.
Can PBT be welded?
Excellent for ultrasonic, hot-plate, vibration, spin and laser welding (with laser-transparent/absorbing pairs); no solvent bonding — use cyanoacrylate/epoxy on abraded, primed surfaces.
Can PBT be formed, bent or molded?
Dry to <0.02% moisture (120 °C, 3–4 h) to prevent hydrolytic MW loss; mold at 240–260 °C melt and 60–90 °C tool, fast fill, and expect anisotropic shrinkage in GF grades — gate to control warp.
What surface finishes work on PBT?
Takes pad printing and laser marking well; painting/metallizing needs plasma or primer pretreatment because of the low-energy, solvent-resistant surface; molded-in texture is usually preferred over polishing.
PBT 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 |
|---|---|---|
| 1,4-butanediol (BDO) unitdiol comonomer of the polyester backbone | ≈ 40 | 40 |
| glass fiber0 for unfilled default; 15/30/40 wt% in GF variants | 0 – 40 | 0 |
| flame retardant + synergistbrominated or halogen-free P-based system + Sb2O3 in FR V-0 grades | 0 – 20 | 0 |
| stabilizers / nucleant / pigmentantioxidant, hydrolysis stabilizer, mold release, carbon black | 0.2 – 2 | 0.8 |
| terephthalic acid / DMT unitdiacid comonomer; balance of resin | balance |
PBT IM — frequently asked
What is PBT IM used for?
PBT IM is typically used for automotive electrical connectors, relay and switch housings, coil bobbins and formers, automotive electronic control unit housings, appliance structural components and sensor bodies. In short: stronger precise PBT.
What is the yield strength of PBT IM?
PBT IM has a typical yield strength of 55 MPa (7.98 ksi) and a tensile strength of 42 MPa (6.09 ksi) — stronger than 62% of polymer grades. Strength varies by condition: see the 10 listed tempers.
Is PBT IM easy to machine?
Reasonably — machinability is rated good (60/100, better than 51% of polymer grades). Machines cleanly with sharp, positive-rake carbide tools and air cooling; glass-filled grades are abrasive and need diamond or coated tooling, and sharp internal corners must be avoided due to notch sensitivity.
Can PBT IM be welded?
Yes — weldability is rated very good (70/100). Excellent for ultrasonic, hot-plate, vibration, spin and laser welding (with laser-transparent/absorbing pairs); no solvent bonding — use cyanoacrylate/epoxy on abraded, primed surfaces.
What surface finishes work on PBT IM?
Takes pad printing and laser marking well; painting/metallizing needs plasma or primer pretreatment because of the low-energy, solvent-resistant surface; molded-in texture is usually preferred over polishing.
Can PBT IM be formed, bent or molded?
Dry to <0.02% moisture (120 °C, 3–4 h) to prevent hydrolytic MW loss; mold at 240–260 °C melt and 60–90 °C tool, fast fill, and expect anisotropic shrinkage in GF grades — gate to control warp.
What is the maximum service temperature of PBT IM?
PBT IM is rated for continuous use to about 110°C (230 °F), and briefly to 160°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in PBT IM?
Yes — PBT IM is available for injection molding with instant online pricing. Upload a STEP file to get a price and a DFM check.
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 CAMPUS data — BASF (2023)
- Crastin PBT thermoplastic polyester resin product guide — Celanese (DuPont Performance Materials) (2023)
- Valox resin product data / processing guide — SABIC (2022)
- Pocan PBT technical information — LANXESS (2023)
- CAMPUS plastics database — PBT ISO 10350 single-point data — CWFG (2024)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
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.