Page 158 - Engineering Plastics Handbook

Chapter
7

Polybutylene Terephthalate (PBT)

Dr. Gi-Dae Choi
LG Chemicals Ltd.
Tech Center EP Team
Daejeon, Korea (Rep.)

Introduction

Polybutylene terephthalate (PBT) resin is a semicrystalline thermoplas-
tics polyester derived from 1,4-butanediol with either terephthalic acid or
dimethyl terephthalate (see Fig. 7.1). The commercial production of PBT
compound for engineering plastic applications was started in the United
States by Celanese in 1970 and grew rapidly as it found utility in various
applications, most commonly in the automotive, electrical, and electron-
ics industries. As engineering thermoplastic polyesters, polyethylene
terephthalate (PET) compounds are also produced. Because of rapid crys-
tallization and easy processing, PBT compounds are more popular engi-
neering thermoplastics than other polyesters. The main difference between
PBT and other commercial polyesters is its fast crystallization character-
istics. This ability to crystallize very fast allows fast cycle times during
injection molding, and complete crystallization during molding leads
to high productivity [1].
PBT is noted for its high heat resistance, stiffness and hardness, excel-
lent electrical properties, and good resistance to environmental influences.
PBT resins are high-performance engineering thermoplastics that can be
used in a variety of applications, most commonly in functional compo-
nents and structural parts that are formed by injection molding. In addi-
tion to unfilled neat PBT grades, impact-modified, glass-reinforced,
mineral-filled, flame-retardant grades and blends based on PBT are

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