Page 273 - Engineering Plastics Handbook

Thermoplastic Polyimide (TPI) 235

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TABLE 10.7 Aurum Wear and Friction Grades
Properties Unit JCL3030 JCF3030 JNF3020

Filler Carbon fiber lubricant Carbon fiber PTFE PTFE
Features High PV High speed
Mating metal Steel, cast iron Steel, cast iron Aluminum
Environment Oil and dry Oil Dry
Specific gravity — 1.42 1.44 1.44
Tensile strength MPa 230 170 72
Flexural modulus GPa 17.1 10.8 2.4
Izod impact J/m 110 110 137

technology has led to its reasonable cost, although the raw material is
expensive.

Processing
Flowability
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Aurum is a thermoplastic, and there are three basic grades of neat
resin, depending on the melt viscosity (Table 10.8).
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Since Aurum is a heat-resistant resin, it is necessary to set the pro-
cessing temperatures high enough. The polyimide has similar spiral
flow length to PES with processing temperatures about 72°F (40°C)
higher than that of PES. Although flow length changes with mold tem-
perature, the degree of such change is relatively small compared with
the influence of processing temperature or pressure. A 54°F (30°C)
change in mold temperature corresponds to approximately a 9°F (5°C)
change in processing temperature.

Predrying conditions before molding
Drying conditions. Required drying time is dependent on the thickness
of resin layer. Normally 10 h or more at 356°F (180°C) is recommended.

Dryer. A shelf-type dryer with hot air circulation with a temperature
control range of 392°F (200°C) or more is recommended.

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TABLE 10.8 Aurum Melt Viscosity and Molecular Weight
Melt viscosity, Melt flow, Molecular weight,
Grade P, at 752°F (400°C) g/10 min, at 752°F (400°C) LALLS*
PL400C 3,000–4,000 12–28 25,000
PL450C 6,000 4.5–9.0 28,000
PL500C 10,000 2.5–4.5 30,000
* LALLS: low-angle light scattering.