A multipurpose material that can be adapted to a wide variety of functions

Key properties

• High dimensional accuracy
• Electrical property
• Acid resistance
• High tracking resistance
• Heat-shock resistance
• Non-halogen
• Glow wire property
• Long-term durability
• Low water absorbability
• Flame resistance
• Superior formability

PBT is a linear thermoplastic saturated polyester containing ester bonds in its main chain. PBT stands for polybutylene terephthalate. It is a polymer belonging to the same family as PET resin.

Structural Formula

PBT possesses a high melting point and high degree of crystallinity, while a low water absorption rate and thermal expansion coefficient give the resin superior dimensional stability. Electrical properties are also superior, and only small changes in electrical properties are exhibited as a result of moisture absorption. Dielectric breakdown voltage is also high.

Both crystalline and non-crystalline structures coexist in PBT. As a result, additives can be readily employed to improve properties and produce various functionalities. Its varied grades include flame resistant grades, fast molding cycle grades, and high impact strength grades. PBT is adopted in a wide variety of familiar products used in everyday life such as electrical components (connectors, micro-switches and condenser cases), office equipment like keyboards, telephones, automotive parts such as in-car electronics and electric vehicle charger guns, medical devices, construction materials, and precision equipment.

Raw ingredients and production method

As PBT is an ester polymer, it is polymerized from esters, themselves synthesized from acids and alcohols. With terephthalic acid used as the acid ingredient and 1, 4-butanediol as the alcohol ingredient, PBT polymer is made via polycondensation. This method is known as the esterification method.

Terephthalic acid is a solid that possesses sublimability and, because purification is difficult, a method also exists whereby terephthalic acid is esterified using methanol, with resulting dimethyl terephthalate and 1, 4-butanediol polycondensated to form the PBT polymer. This method is “ester interchange.” Regardless of which method is employed to manufacture the PBT polymer, the same properties and performance are exhibited if the molecular weight is the same.

While unreinforced PBT is used widely, in general, the addition of reinforcing material improves mechanical and thermal properties. By incorporating various reinforcing materials, many grades of the PBT polymer with various characteristics are made.

List of leading grades

^*grade introduction

Applications

Product information

• Unreinforced / Flame resistant
  High shock grades

• Laser welding technology

• Metal adhesion technology