When you hear the word “polyester,” what’s the first thing that comes to mind? If you’re like most people, it’s clothing. You may not know that polyester — including polybutylene terephthalate (PBT) — isn’t just fabric. 
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⁠PBT is a type of plastic and an incredibly versatile member of the polyester family. The polybutylene terephthalate market is vast — you’ll find it in everything from your car to kitchenware. 
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⁠Now, let’s look at the unique properties of PBT resin that make it such a popular material.
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Where did polybutylene terephthalate come from? 

The most recently engineered plastic, polybutylene terephthalate (PBT) was first discovered in the mid-20th century by a team studying synthetic polymers at General Electric Company (USA). Nearly 20 years after its initial discovery, Celanese Corporation (USA) began commercially producing glass fiber-reinforced PBT in 1971 under the name “Celanex.” Since its introduction to the consumer market, PBT has significantly evolved leading to processing upgrades, improved properties, sustainability advancements and more.
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How is PBT made?

Compared to other plastics, polybutylene terephthalate isn’t relatively complex, with just two main ingredients: liquid 1 1,4-butanediol (BDO) and solid terephthalic acid (TPA). A similar solid — dimethyl terephthalate (DMT) — can also be used. Both mixtures result in an intermediate substance, but TPA will produce water, and DMT will produce methanol.
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⁠The process is as follows:

1. Mix and heat 1,4-butanedio and TPA or DMT to form an intermediate substance
2. Polymerize intermediate substance to form long chains
3. Cool and cut into plastic pellets
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What are the different types of PBT?

Thanks to its versatility, modifications to the production process — including additives and fillers — will result in different PBT resins. Based on final product needs, common types of PBT include, but are not limited to:
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• Unfilled: No additives; chemical resistant
• Glass Filled: Glass fiber additives; enhanced strength and rigidity
• Mineral Filled: Additives include talc, mica and others; increased stability and reduced warpage
• Flame retardant: Combination of compound additives; flame and heat resistant
• Impact modified: Rubber or other modifiers added; improved resilience and resistance
• UV stabilized: Combination of compound additives; absorbs light and resists breakdown
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Why is PBT Used?

PBT adaptability means it is easy processed using injection molding, extrusion, blow molding and other processes. Its characteristics include:

• High strength and elasticity
• Minor creep deformation with significant creep rupture strength 
• Elevated heat resistance
• Low water absorption
• Dimensional stability
• Resistance to organic solvents and oils
•  Excellent arc resistance and tracking resistance
•  High flame-retardant performance
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These versatile properties make PBT material widespread in manufacturing across different industries, like:

•  Automotive: Fuel systems, sensors, interior trim, electrical connectors
• Electronics: Sockets, switches, circuit breakers, coil formers
• Consumer Goods: Tools, toys, sporting good, fabric, kitchenware, medical devices
• Packaging: Food containers, bottles, closures
• Machinery: Gears, bearings, rollers, pump parts
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Polybutylene Terephthalate FAQ

Q: Is PBT resin safe?
⁠A: When used as intended and safety guidelines are adhered to, PBT is considered safe.
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⁠Q: Is PBT biodegradable?
⁠A: No, PBT is not considered biodegradable.
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⁠Q: What is PBT fabric?
⁠A: This refers to textiles made from PBT, including swimwear, activewear, undergarments, bedding and upholstery.
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⁠Q: What are PBT medical uses?
⁠A: Products made with PBT (including PBT-GF30) are used in medical device components, surgical instruments, prosthetics, dental implants, packaging and more.
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⁠Q: What are the pros and cons of PBT?
⁠A: PBT is easy to process, chemical and heat resistant, durable and visually appealing. However, PBT tends to be more expensive than other plastics, has limited flame resistance, suffers from color stability and brittleness in cold climates.