What is Polybutylene Terephthalate (PBT)?
Injection moulded polybutylene terephthalate (PBT) is a strong, semi-crystalline material that exhibits excellent mechanical and electrical properties (high dielectric strength and insulation resistance), all of which are stable over a broad range of environmental conditions.
Mechanical properties
| Typical Value/Unit |
|---|
| Flexural Modulus | 9 GPa |
| Tensile Modulus | 9800 MPa |
| Tensile Strength | 130 MPa |
| Elongation at Break | 2.5% |
| Flexural Strength | 210 MPa |
| Hardness (Shore D) | 170 |
Physical Properties
| Typical Value/Unit |
|---|
| Density | 1.52g/cm3 |
Advantages of PBT injection moulding
- Excellent Mechanical Properties: PBT exhibits high tensile strength, stiffness and impact resistance. This makes it suitable for applications that require structural integrity and durability.
- Good Heat resistance: PBT has a relatively high melting point and good heat resistance. It can withstand temperatures ranging from -30°C to 150°C, making it suitable for applications exposed to heat, including under-the-hood automotive parts and electrical components.
- Chemical Resistance to Many Chemicals: Polybutylene Terephthalate shows good resistance to a wide range of chemicals, including solvents, oils, acids and bases.
- Great Electrical Insulation Properties: PBT is an excellent electrical insulator with good dielectric strength, low moisture absorption and high volume resistivity.
- Good Surface Finish: PBT can be easily moulded to achieve a smooth and glossy surface finish, reducing the need for additional post-processing or surface treatments.
Disadvantages of PBT injection moulding
While polybutylene terephthalate has many advantages, its not without its disadvantages. It’s important to evaluate these limitations against the specific requirement of the application of your part before selecting PBT as a material choice.
- Limited Chemical Resistance: While PBT exhibits good resistance to many chemicals, it’s not as chemically resistance as engineering plastics like PEEK or PPS. PBT may experience degradation or swelling when exposed to aggressive chemicals, including strong acids and bases.
- Higher in Cost: PBT is generally more expensive than commodity plastics like polypropylene (PP) or polyethylene (PE). Its higher cost can make it less suitable for price-sensitive applications where lower-cost alternatives can meet the required specifications.
- Tendency to Warp: polybutylene terephthalate, especially when reinforced with glass fibres (GF), has the tendency to warp or undergo dimensional changes.
What is PBT material used for?
Polybutylene terephthalate is a versatile material with a wide range of applications across the automotive, electronics and many other industries. Some typical applications of PBT include:
- Connectors, sockets, switches, and circuit breakers
- Under-the-hood automotive components such as engine covers
- Pump housings, pipe fittings, valve bodies
- Components with biocompatible properties
Get injection moulding parts in PBT material
At HLH Rapid, we offer an extensive selection of resins to cater to your specific custom injection moulding needs, including Polybutylene Terephthalate. To obtain a quote, simply upload your CAD file HERE and provide us with the details of your project including quantity, material and any surface finish requirements. Our dedicated team will then get back to you with a quote within a day.
