A Guide
to PBT
Reference
Sheet
Material Safety Data Sheet
UL Information
What is PBT?
The letters PBT stand for polybutylene terephthalate, an engineering
thermoplastic.
What are the properties of PBT?
PBT has a high crystallinity which determines much of its properties.
PBT has low polarity and thus low water absorption. PBT is degraded
by prolonged exposure to hot water or steam via chemical reaction.
PBT's high crystallinity gives it excellent chemical resistance
to most organic solvents. At low temperatures (less than 130°F),
PBT has excellent wear resistance. Its electrical properties
are stable under varying conditions. PBT takes fillers and additives
well, and it can be dyed. Properties of PBT include the following:
- good physical properties
- excellent wear resistance
- excellent chemical resistance
- high heat resistance (reinforced grades only)
- opaque
- moderate price
- fair processing
What are the applications of PBT?
An important application of PBT is keyboard buttons. PBT has
the wear resistance, chemical resistance, and strength for the
application; and perhaps more importantly, it can be dyed. With
other plastics, it was necessary to make a separate mold for each
button. Since PBT can be dyed, one can use a single mold for
every button; and the graphic for a particular button can be died
onto the button by a process called sublimation printing. Typical
applications of PBT include the following:
- typewriter, computer keybuttons
- gears, cams, and bushings
- electrical bobbins and rotors
- electrical connectors and relays
- pump housings and impellers
- auto distributors and starters
- automotive headlight brackets
UL Information on Trivox®
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