PBT Resin

What is PBT Resin?

PBT  (polybutylene terephthalate) is a semi-crystalline engineering thermoplastic material that offers very good chemical resistance with high levels of mechanical and thermal properties. PBT material  has good dimensional stability and is unaffected by ambient humidity. This semi-crystalline thermoplastic also has low friction and resistance to abrasion. The addition of additives can further enhance pbt material properties

The rigidity of Polybutylene terephthalate can be increased by the addition of glass fibers in a loading range of 10% to 40%. Flame retardants can be added to TP to provide performance profiles required for electrical/electronics applications. Although TP is not as ductile as other materials, such as polycarbonate, impact modifiers can be added to provide high impact products. Additives can also be combined to give the products broad property profiles. Examples of this include flame retardant glass filled TP, and flame retardant impact-modified Polybutylene terephthalate.

The semi-crystalline nature of PBT material  causes it to have both higher shrinkage values and higher specific gravity values than amorphous thermoplastics. These factors should be taken into account when designing parts.

Additives, Modifiers, and Reinforcing Agents:
  • Additives – UV stability, easy release (mold releases), colorants, and other stability additives
  • Modifiers – Flame retardants, impact modifiers, flow enhancers
  • Reinforcing Agents – Glass fibers, mineral fillers

Datasheets with full PBT Material Properties

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Q. What are the advantages and disadvantages of PBT?
A. This semi-crystalline engineering thermoplastic offers excellent resistance to a wide range of chemicals. Its semi-crystalline structure helps to promote processing. Fiber reinforcement can be used to enhance both mechanical and thermal properties, and impact modifier technology can be used to improve impact properties. As thermal properties go, PBT falls in the middle range of engineering thermoplastics. Disadvantages include a tendency to warp when glass fiber reinforcement is used. The resin also has a low Notched Izod impact relative to most engineering thermoplastics. The semicrystalline structure of PBT results in higher mold shrinkage compared to that of amorphous engineering thermoplastics.
Q. How does PBT compare to polyethylene terephthalate (PET)?
A. Both PBT and PET are classified as polyesters, but PBT has an advantage in that it crystallizes more easily than PET. This property allows PBT to be processed more easily than PET. On the other hand, when PET is allowed to crystallize, it has a higher melting point (250C – 260C) than PBT (220C – 230C). This slow crystallization allows PET to be used for transparent applications, while the semi-crystalline structure of PBT prevents this material from being transparent.
Q. What is PBT used for?
A. Polybutylene terephthalate can be used for interior and exterior automotive parts, particularly electrical components such as sensor housings, switches and connectors, and under-hood parts exposed to harsh conditions, such as fuel system components. The material is also a good option for signal and power applications in the electrical and electronics (E/E) sector. Additionally, it is used in consumer goods, including small appliances and tools.
Q. Is PBT flame retardant?
A. Polybutylene terephthalate is not inherently flame retardant but can be enhanced with additives. While flame retardants containing bromine (a halogen) are commonly used for PBT, non-halogenated technology is available.

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My mission at Polymer Resources has not changed since I founded this company more than four decades ago. It includes continuing our tradition of financial stability, sustainable growth and visionary leadership that compounds success for customers, suppliers and employees. It also means proudly manufacturing our products in America, and making them available to the global marketplace.

Les Klein, Chief Executive Officer, Polymer Resources, Ltd.


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